Publisher: AIP   (Total: 28 journals)   [Sort alphabetically]

Showing 1 - 27 of 27 Journals sorted by number of followers
Physics Today     Hybrid Journal   (Followers: 77, SJR: 0.66, CiteScore: 1)
J. of Applied Physics     Hybrid Journal   (Followers: 69, SJR: 0.739, CiteScore: 2)
Physics of Fluids     Hybrid Journal   (Followers: 58, SJR: 1.19, CiteScore: 3)
Applied Physics Letters     Hybrid Journal   (Followers: 52, SJR: 1.382, CiteScore: 3)
J. of Chemical Physics     Hybrid Journal   (Followers: 37, SJR: 1.252, CiteScore: 2)
J. of Mathematical Physics     Hybrid Journal   (Followers: 26, SJR: 0.644, CiteScore: 1)
Review of Scientific Instruments     Hybrid Journal   (Followers: 21, SJR: 0.585, CiteScore: 1)
Applied Physics Reviews     Hybrid Journal   (Followers: 15, SJR: 4.156, CiteScore: 12)
J. of Laser Applications     Full-text available via subscription   (Followers: 14, SJR: 0.741, CiteScore: 2)
J. of Renewable and Sustainable Energy     Hybrid Journal   (Followers: 14, SJR: 0.44, CiteScore: 1)
Physics of Plasmas     Hybrid Journal   (Followers: 11, SJR: 0.576, CiteScore: 1)
Acoustics Today     Hybrid Journal   (Followers: 10)
APL Materials     Open Access   (Followers: 10, SJR: 1.63, CiteScore: 4)
AIP Advances     Open Access   (Followers: 7, SJR: 0.472, CiteScore: 1)
Biomicrofluidics     Open Access   (Followers: 6, SJR: 0.592, CiteScore: 2)
Low Temperature Physics     Hybrid Journal   (Followers: 6, SJR: 0.264, CiteScore: 1)
Structural Dynamics     Open Access   (Followers: 6, SJR: 1.625, CiteScore: 4)
Chaos : An Interdisciplinary J. of Nonlinear Science     Hybrid Journal   (Followers: 4, SJR: 0.716, CiteScore: 2)
J. of Physical and Chemical Reference Data     Hybrid Journal   (Followers: 3, SJR: 1.046, CiteScore: 3)
Virtual J. of Quantum Information     Hybrid Journal   (Followers: 3)
AIP Conference Proceedings     Full-text available via subscription   (Followers: 2)
Biointerphases     Open Access   (Followers: 1, SJR: 0.558, CiteScore: 2)
Chinese J. of Chemical Physics     Hybrid Journal   (Followers: 1, SJR: 0.24, CiteScore: 1)
Surface Science Spectra     Hybrid Journal   (Followers: 1, SJR: 0.416, CiteScore: 1)
APL Photonics     Open Access   (Followers: 1)
Scilight     Full-text available via subscription  
APL Bioengineering     Open Access  
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AIP Advances
Journal Prestige (SJR): 0.472
Citation Impact (citeScore): 1
Number of Followers: 7  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2158-3226
Published by AIP Homepage  [28 journals]
  • Reduced order model for hard magnetic films

    • First page: 025001
      Abstract: In the pursuit of rare earth-lean permanent magnets for green technologies, microstructural optimisation offers a promising strategy to enhance coercivity while minimising critical element content. For this approach, the combination of experimental work on hard magnetic films and numerical investigations is necessary. However, computational limitations restrict micromagnetics to small systems, motivating the development of a reduced order model for investigating large multigrain systems. The model is based on the embedded Stoner-Wohlfarth method and is used to investigate the influence of a nonmagnetic grain boundary phase thickness and the aspect ratio of the magnetic grains on the overall coercivity. It is possible to simulate large NdFeB multigrain structures which can be compared to hard magnetic films. We derive design recommendations to increase coercivity by increasing the grain boundary phase thickness and the aspect ratio of the grains in hard magnetic materials.
      PubDate: Thu, 01 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000816
      Issue No: Vol. 14, No. 2 (2024)
       
  • Optimization of the 3D multi-level SOT-MRAMs

    • First page: 025002
      Abstract: With the development of electronic technology, semiconductor memory is gradually shifting toward smaller area with less power consumption. SOT-MRAM is one of the competitive substitutes for DRAM and SRAM due to its superior endurance and switching speed. In contrast to STT-MRAM, the separation of read and write routes allows SOT-MRAM to have a lower error rate and higher lifetime, but this comes at the expense of the memory density. In recent years, vertical integrated circuits have relied on TSV to complete 3D stacking to ease the pressure of Moore's Law on scaling circuits. SOT-MRAM can take advantage of 3D stacking to reduce power and latency. More importantly, the density of SOT-MRAM can be improved at the same time. In the paper, simulation is conducted based on DESTINY, with the TSV model supplemented to NVSIM to evaluate the performance of MRAM 3D structures. The 3D SOT-MRAM structure in DESTINY can be implemented with a bus layer and interconnect structure between layers, which greatly reduces the expense of area. However, the 3D structure requires a more complex interconnect structure to truly meet the requirements of high density. For this reason, 3D model of unit interconnection using TSV is presented in the paper. Memory has several components, of which the memory array is the one with the largest area share. This paper explores the spatial structure of the array and proposes a new model which allows more complex interconnect structures to be accomplished on the same area.
      PubDate: Thu, 01 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000708
      Issue No: Vol. 14, No. 2 (2024)
       
  • 151 Eu Mössbauer study of magnetic ordering in flux-grown ferromagnetic
           and antiferromagnetic forms of EuCd 2 As 2

    • First page: 025003
      Abstract: EuCd2As2 is a remarkably complex magnetic semimetal that may behave as a topological insulator or host two pairs of Weyl points, depending on the growth conditions and the final magnetic state. Both antiferromagnetic (AFM) and ferromagnetic (FM) forms have been grown, and we show here, using 151Eu Mössbauer spectroscopy, that the differences between the AFM and FM forms extend well beyond their ground state magnetic structures. Whereas the AFM form undergoes a conventional AFM → paramagnetic transition on warming, the FM form passes through a complex incommensurate modulated state before becoming paramagnetic.
      PubDate: Thu, 01 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000623
      Issue No: Vol. 14, No. 2 (2024)
       
  • Machine learning based classification of vector field configurations

    • First page: 025004
      Abstract: Magnetic materials at the nanoscale are important for science and technology. A key aspect for their research and advancement is the understanding of the emerging magnetization vector field configurations within samples and devices. A systematic parameter space exploration—varying for example material parameters, temperature, or sample geometry—leads to the creation of many thousands of field configurations that need to be sighted and classified. This task is usually carried out manually, for example by looking at a visual representation of the field configurations. We report that it is possible to automate this process using an unsupervised machine learning algorithm, greatly reducing the human effort. We use a combination of convolutional auto-encoder and density-based spatial clustering of applications with noise (DBSCAN) algorithm. To evaluate the method, we create the magnetic phase diagram of a FeGe disc as a function of changing external magnetic field using computer simulation to generate the configurations. We find that the classification algorithm is accurate, fast, requires little human intervention, and compares well against the published results in the literature on the same material geometry and range of external fields. Our study shows that machine learning can be a powerful tool in the research of magnetic materials by automating the classification of magnetization field configurations.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000686
      Issue No: Vol. 14, No. 2 (2024)
       
  • Combining annealing temperature and interface engineering for improving
           anisotropic magnetoresistance in Ta/NiFe/Ta films

    • First page: 025005
      Abstract: Anisotropic magnetoresistance (AMR) sensors are pivotal in various applications due to their low power consumption, scalability, and cost-effectiveness due to the simple sensor structure, comprising one NiFe film, usually encased in a buffer and cap layer. In this work, we explore the effects of inserting MgO and Pt dusting layers between the NiFe sensing layer and adjacent capping and buffer layers, on the electric, magnetic and structural properties of AMR sensors. We describe results on sensors based on Ta/NiFe/Ta, with an as-processed AMR value of 2.0 %. The insertion of Pt thin films had a positive impact, with AMR values increasing to 2.2 %, contrary to the observed with MgO dusting films. Magnetic annealing up to 370 °C caused an increase of the resistivity and reduction in AMR (with Pt dusting layers), on the contrary, MgO dusting layers improved the sensor performance upon annealing, with AMR increasing to 2.5 % (5 h at 370 °C). In light of the findings, the incorporation of Pt and MgO dusting layers enables tailoring the grain size and resistance of Ta/NiFe/Ta films, while combined with proper annealing, which is relevant for applications where Ta and NiFe are available for AMR sensor fabrication.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000692
      Issue No: Vol. 14, No. 2 (2024)
       
  • Experimental evidence for ultrashort-lived spin polarons in EuSe

    • First page: 025006
      Abstract: We investigated the time evolution of the density of giant spin polarons in a magnetic semiconductor. Spin polarons (SPs) were photoexcited and observed using time-resolved Faraday rotation. We find the existence of two types of SPs, a short-lived spin polaron with a lifetime of around τsl = 0.5 ns and a long-lived spin polaron with a lifetime of τll = 0.45 ± 0.03 µs, at T = 5 K. The stark difference of three order of magnitude between these lifetimes suggests that in the long lived SP the electron-hole pair is relaxed and its recombination is forbidden. The short-lived SP is probably associated with SP recombination before such relaxation has occured. An extraordinary finding is that the magnitude of τsl, as well as its decrease with increasing temperature, reproduces exactly the characteristic time for SP growth. This suggests that the thermal fluctuations, responsible for SP magnetic moment growth, are also responsible for increasing the recombination probability of SPs.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000820
      Issue No: Vol. 14, No. 2 (2024)
       
  • A pole-changing flux reversal permanent magnet motor

    • First page: 025007
      Abstract: In this paper, a pole-changing (PC) flux reversal permanent magnet (FRPM) motor is proposed for obtaining a wide speed range. According to the general air-gap field modulation theory, the permanent magnet (PM) magnetic field is modulated into a series of harmonics with different pole numbers by rotor teeth. By introducing an especial PM arrangement, two groups of working harmonics with different pole-pair numbers are generated in the proposed 12-7 PC-FRPM motor due to the modulation of rotor teeth. Based on the calculated slot pitch angles of these harmonics, two winding connections can be obtained for PC operation to achieve two operating modes. The electromagnetic performance of PC-FRPM motor before and after PC are analyzed using finite element analysis and verified by the experimental test results.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000679
      Issue No: Vol. 14, No. 2 (2024)
       
  • Magnetic properties of (Sm, Zr)(Fe, Co) 10−x Ti x (x = 0, 0.5, 1)
           bulk magnets

    • First page: 025008
      Abstract: It would be desirable if the magnetic properties of Sm–Fe alloys could be increased without the need for nitrogenation. In this experiment, Sm–Fe bulk magnets were prepared from the Sm–Fe powders by the spark plasma sintering (SPS) technique without nitrogenation. The structures and magnetic properties of the Sm–Fe bulk magnets prepared by the SPS technique were investigated. By optimization of the composition and production process, it was found that the (Sm0.7Zr0.3)(Fe0.7Co0.3)9Ti magnet with the fine Th2Zn17-type phase showed a high coercivity of 4.35 kOe.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000629
      Issue No: Vol. 14, No. 2 (2024)
       
  • Characteristics of blood flow velocity in the radial artery and finger
           capillaries using magnetoplethysmogram and photoplethysmogram

    • First page: 025009
      Abstract: The Hall element and optical sensor, which can detect the magnetic field change caused by the minute fluctuations of the permanent magnet according to the periodic movement of the radial artery and the light absorption and reflection intensity according to the change in wrist blood flow, respectively, are used as key elements in digital healthcare devices. The pulse waves of the radial artery inside the wrist were measured and analyzed using a clip-type pulsimeter, magnetoplethysmogram (MPG). The pulse wave, which is the change in blood flow obtained by photoplethysmogram (PPG), was measured on the dorsal side of the wrist or the fingers simultaneously with MPG. The ABFV (artery blood flow velocity) is a few ten cm/s as DH (distance between MPG and PPG) divided by ΔT(a) which is the time difference between the first peaks of MPG and PPG waveforms on the dorsal side of the wrist. The PBFV (peripheral blood flow velocity) is a few mm/s as LH (hand length) divided by ΔT(p), which is the time difference between the first peak of MPG waveform and the third peak PPG waveform on the finger. For four subjects of 20s, SPWV was approximately 0.98∼1.19 m/s, ABFV in the radial artery was approximately 0.40∼0.44 m/s, and finger capillary PBFV was approximately 6.3∼8.6 cm/s. These results show reasonable values similar to the blood velocity of many blood vessels flowing through the human body.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000793
      Issue No: Vol. 14, No. 2 (2024)
       
  • Acoustic metamaterials for realizing a scalable multiple phi-bit unitary
           transformation

    • First page: 025010
      Abstract: The analogy between acoustic modes in nonlinear metamaterials and quantum computing platforms constituted of correlated two-level systems opens new frontiers in information science. We use an inductive procedure to demonstrate scalable initialization of and scalable unitary transformations on superpositions of states of multiple correlated logical phi-bits, classical nonlinear acoustic analog of qubits. A multiple phi-bit state representation as a complex vector in a high-dimensional, exponentially scaling Hilbert space is shown to correspond with the state of logical phi-bits represented in a low-dimensional linearly scaling physical space of an externally driven acoustic metamaterial. Manipulation of the phi-bits in the physical space enables the implementation of a non-trivial multiple phi-bit unitary transformation that scales exponentially. This scalable transformation operates in parallel on the components of the multiple phi-bit complex state vector, requiring only a single physical action on the metamaterial. This work demonstrates that acoustic metamaterials offer a viable path toward achieving massively parallel information processing capabilities that can challenge current quantum computing paradigms.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0188462
      Issue No: Vol. 14, No. 2 (2024)
       
  • The influence mechanism of leakage inductance and distributed capacitance
           on nanosecond pulse transformer-type trigger

    • First page: 025011
      Abstract: The pulse trigger generator exerts a significant impact on the Marx generator’s output pulse (OP). In this paper, a pulse transformer (PT)-type trigger device is intended to give a pulse of front steepness below 30 ns, a half-width of more than 300 ns, and a magnitude of 50 kV to a 4 MV Marx generator. A steepening circuit is modeled on the output side of the PT equivalent circuit to reduce the OP front steepness, establishing the model of a closed-core PT-type trigger generator. The influence of distributed capacitance and leakage inductance (parasitic parameters) of the PT winding on the OP magnitude, triggering delay time, and front steepness are analyzed, and the design scheme of the PT is decided accordingly. Then, the pulse trigger generator model is simulated, and the trigger pulses are obtained in accordance with the design index. The OP waveforms are tested using a newly developed pulse trigger device prototype.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0180161
      Issue No: Vol. 14, No. 2 (2024)
       
  • The effect of gamma ray irradiation on few layered MoSe 2 : A material for
           nuclear and space applications

    • First page: 025012
      Abstract: In recent years, emerging two-dimensional (2D) materials, such as molybdenum diselenide (MoSe2), have been at the center of attention for many researchers. This is due to their unique and fascinating physicochemical properties that make them attractive in space and defense applications that include shielding harsh irradiation environments. In this study, we examined the effects of gamma (γ) rays at various doses on the structural, chemical, and optical properties of MoSe2 layers. After the samples were exposed to intense gamma radiation (from a 60Co source) with various exposure times to vary the total accumulated dosage (up to 100 kGy), Raman and photoluminescence spectroscopies were used to study and probe radiation-induced changes to the samples. When compared to pristine materials, very few changes in optical properties were typically observed, indicating good robustness with little sensitivity, even at relatively high doses of gamma radiation. The imaging using scanning electron microscopy revealed a number of nano-hillocks that were connected to substrate alterations. X-ray photoelectron spectroscopies revealed that Mo’s binding energies remained the same, but Se’s binding energies blueshifted. We associated this shift with the decrease in Se vacancies that occurred after irradiation as a result of Mo atoms creating adatoms next to Se atoms. When compared to pristine materials, very few changes in optical, chemical, and structural properties were typically observed. These findings highlight the inherent resilience of MoSe2 in hostile radioactive conditions, which spurs additional research into their optical, electrical, and structural characteristics as well as exploration for potential space, energy, and defense applications.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0170064
      Issue No: Vol. 14, No. 2 (2024)
       
  • Investigation of the influence of different liquid temperatures on the
           dynamics of long-pulse laser-induced cavitation bubbles

    • First page: 025013
      Abstract: Long-Pulse Laser-induced cavitation bubbles have been identified to hold significant applications in various fields, such as industry and medicine. In this study, the dynamics of cavitation bubbles, induced by a 2.94 μm wavelength Er:YAG laser with an energy of 20 ±1 mJ and transmitted via sapphire fiber optics into distilled water at different temperatures, were investigated. The adiabatic expansion theory was utilized to predict the maximum length (Lmax) and the maximum width (Wmax) of the cavitation bubbles at different liquid temperatures. Excellent alignment was observed between the theoretical predictions and the experimental data. Using this theory, the local overheated liquid temperature was deduced to be ∼180 °C during the formation of cavitation bubbles. It was found that as the liquid temperature increased, the collapse position of the cavitation bubbles, relative to the normalized distance (γ) from the fiber end face, decreased. This study reveals the importance of considering the potential risk of damage to fiber optics from the shockwaves and microjet streams generated by cavitation bubbles in high-temperature conditions.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0185608
      Issue No: Vol. 14, No. 2 (2024)
       
  • Early mechanical properties and strength calculation method of slag-based
           alkali activated concrete

    • First page: 025014
      Abstract: The use of slag-based alkali-activated concrete (AAC) could effectively address the issues of resource extraction and carbon emissions caused by traditional Portland cement. In this study, the effects of the fly ash content, water–binder ratio, and alkali activation modulus on the early mechanical properties of AAC were investigated. A total of 105 cube specimens (35 sets) were designed and subjected to compressive strength tests, scanning electron microscope tests, and x-ray diffraction composition analysis. The results indicated that excellent early strength was observed in AAC, with a compressive strength reaching ∼90% of the 28th day strength before 14 days. An increase in the fly ash content and a decrease in the water–binder ratio significantly improved the compressive strength within the same age period. The impact of a lower alkaline activation modulus on strength was found to be insignificant. Based on the experimental results, a calculation method and a constitutive model for early strength were proposed, and the theoretical values exhibited a high level of agreement with the measured values.
      PubDate: Tue, 06 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0194129
      Issue No: Vol. 14, No. 2 (2024)
       
  • Design considerations for magnetic field generators for future switching
           applications

    • First page: 025015
      Abstract: Widespread adoption of Magnetic Field Generators (MFG) will require most electro-optical systems to incorporate high current devices, thereby demanding decreased power consumption due to loss reduction. Recent progress in magnetic field generator typologies has shown ways of reducing form factor while meeting better performance in terms of max current and magnetic field level based on selected transistor technologies. However, developments in the standardization of MFGs need to be considered for optoelectronic industrial-scale applications. This work describes a strategy for identifying the optimum condition for a high magnetic field, form factors contributing to power consumption, and the feasibility of such magneto optical.
      PubDate: Wed, 07 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000698
      Issue No: Vol. 14, No. 2 (2024)
       
  • Omega motion, rolling, and active standing of a worm-inspired robot under
           the action of the magnetic field

    • First page: 025016
      Abstract: With the rapid development of origami technologies, worm-inspired robots have attracted a great deal of attention due to their flexible locomotion characteristics. In the present work, we have prepared a soft robot inspired by the worms, which can achieve various locomotion patterns under the actuation of magnetic field. First, the origami technique is used to form the backbone of the robot, and two NdFeB discs are adhered on its two ends. Next, the experiments for controlling the Omega motion and rolling of the robot are performed, and the mechanical analyses are given. In the experiments, the Omega locomotion speed and rolling speed can reach ∼5 mm/s and 2π rad/s, respectively. Then, two typical examples on the composite motion, including the Omega motion and rolling, are demonstrated, where the robot can realize the tasks of sweeping objects and obstacle crossing in unstructured environments. We further design a system to mimic the situation when the worm-like robot detects and responds to the dangerous signal, and the power of the electromagnet can be accurately controlled. These findings cast a new light on engineering intelligent robots and devices originating from the inspirations of living creatures.
      PubDate: Thu, 08 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0186342
      Issue No: Vol. 14, No. 2 (2024)
       
  • The preparation and properties of photocatalytic composites based on
           palygorskite/molybdenum disulfide

    • First page: 025017
      Abstract: The pollution problem resulting from advancements in science and technology is increasingly severe, particularly concerning organic pollution. Photocatalytic technology is considered one of the most effective methods for treating organic pollution due to its cost-effectiveness, simplicity of operation, high efficiency, and versatility. In this study, palygorskite was purified and extracted using techniques such as ultrasonication, high-speed stirring, centrifugation, and others. Molybdenum disulfide (MoS2) was synthesized in situ on the palygorskite surface through hydrothermal synthesis, resulting in palygorskite/MoS2 nanocomposites. The structure and apparent morphology of the palygorskite/MoS2 composites were analyzed using characterization methods such as transmission electron microscopy, x-ray diffraction, Fourier transform infrared spectroscopy, and others. MoS2 interacted with the hydroxyl groups on the palygorskite surface through amino groups, leading to the dispersion of MoS2 nanosheets on the palygorskite surface, forming a unique nanoflower structure. To assess the photocatalytic degradation performance of palygorskite/MoS2 composites, Rhodamine B was employed as the target pollutant. Under conditions of a pH of 6, a reaction time of 170 min, and a solution concentration of 1500 mg/l, palygorskite/MoS2 composites achieved a Rhodamine B removal amount of 371.73 mg/g. Notably, these composites facilitated the degradation of Rhodamine B into intermediate chain-broken products. The findings of this study hold significant implications for the advancement of clay mineral-based photocatalytic composites and the effective removal of organic pollutants.
      PubDate: Thu, 08 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0187789
      Issue No: Vol. 14, No. 2 (2024)
       
  • Ultrafast spin–orbit torque-induced magnetization switching in a
           75°-canted magnetic tunnel junction

    • First page: 025018
      Abstract: We investigate the switching dynamics of a 75°-canted Spin–orbit torque (SOT) device with an in-plane easy axis using the micro-magnetic simulation. The switching time (τ) is evaluated from the time evolution of the magnetization. The device with a strong out-of-plane magnetic anisotropy (μ0Hkeff = −0.08 T) shows τ = 0.19 ns while a device with a strong in-plane magnetic anisotropy (μ0Hkeff = −0.9 T) shows τ = 0.32 ns. The increase of the damping constant (α) results in the increase of τ for both devices and the sub-nanosecond switching could be retained as α < 0.14 in the device with μ0Hkeff = −0.08 T, while this was achieved as α < 0.04 in the device with μ0Hkeff = −0.9 T. Furthermore when the field-like coefficient (β) is increased, it leads to a decrease in τ, which can be reduced to 0.03 ns by increasing β to 1 in the device with μ0Hkeff = −0.08 T. In order to achieve the same result in the device with μ0Hkeff = −0.9 T, β must be increased to 6. These results indicate a way to achieve ultrafast field-free SOT switching of a few tens of picoseconds in nanometer-sized magnetic tunnel junction (MTJ) devices.
      PubDate: Thu, 08 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000789
      Issue No: Vol. 14, No. 2 (2024)
       
  • L 1 0 FePd-based perpendicular magnetic tunnel junctions with 65% tunnel
           magnetoresistance and ultralow switching current density

    • First page: 025019
      Abstract: L10 FePd is increasingly recognized as a potential candidate for magnetic tunnel junctions (MTJs), yet there remains room for enhancing device performance. In this work, we fabricated fully-integrated L10 FePd-based perpendicular MTJ devices and achieved a significant increase in tunnel magnetoresistance, reaching ∼65%, compared to the previous record of 25%. Notably, we observed bi-directional switching with a low switching current density of about 1.4 × 105 A/cm2, which outperforms the typical spin-transfer torque (STT) MTJ by about one order of magnitude. We propose two possible mechanisms to elucidate the switching process and associated device performance: (1) The voltage-controlled exchange coupling-driven switching of the bottom CoFeB layer; (2) The STT-driven switching of the exchange-coupled L10 FePd–CoFeB composite. While additional research is necessary, these findings may further advance the integration of L10 FePd into spintronic devices, potentially enabling low-energy memory and logic technologies.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000818
      Issue No: Vol. 14, No. 2 (2024)
       
  • Reduction effect of coercivity of electroplated Fe-Pt film magnets by
           chloride ion in plating baths

    • First page: 025020
      Abstract: We recently reported the electroplating of Fe-Pt thick films using plating baths with varying concentrations of NaCl, suggesting the potential for coercivity enhancement by Na ions. In the present study, our focus shifted to not Na ions but Cl ones, and we investigated the effect of the Cl ions on the crystal structures and magnetic properties of electroplated Fe-Pt films. With the increasing concentration of Cl ions, the coercivity of the films decreased. Furthermore, XRD analysis suggested that the Cl ions in the plating baths prevent the L10 ordering of the Fe-Pt crystalline phase, leading us to conclude that a Cl-free bath is favorable for preparing Fe-Pt thick-film magnets with high coercivity.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000776
      Issue No: Vol. 14, No. 2 (2024)
       
  • Role of interdiffusion on the magnetism of ultrathin LaMnO 3 films

    • First page: 025021
      Abstract: We present a detailed study of the magnetic, spectroscopic and structural properties of ultrathin LaMnO3 films deposited on SrTiO3(001) substrates by oxide molecular beam epitaxy. We find that the as-grown LaMnO3 films are slightly reduced and present a significant magnetic moment, while annealing to 600 °C fully oxidizes and enhances its magnetic properties. From synchrotron x-ray photoemission spectromicroscopy, we find the presence of Sr, Ca and Si in the LaMnO3 film that diffuse from the SrTiO3 substrate; these impurities act as hole dopants, and can explain the presence of ferromagnetism in LaMnO3. This work highlights the importance of cation mobility at the elevated growth temperature in modifying the magnetic properties of ultrathin LaMnO3 films.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000803
      Issue No: Vol. 14, No. 2 (2024)
       
  • The magnetic anisotropy of field-assisted 3D printed nylon strontium
           ferrite composites

    • First page: 025022
      Abstract: Magnetic Field Assisted Additive Manufacturing (MFAAM), 3D printing in a magnetic field, has the potential to fabricate high magnetic strength anisotropic bonded magnets. Here, 10, 35, and 54 wt% strontium ferrite bonded magnets using polyamide 12 binder were developed by twin screw compounding process and then printed via MFAAM samples in zero, and in 0.5 Tesla (H parallel to the print direction and print bed). The hysteresis curves were measured using a MicroSense EZ9 Vibrating Sample Magnetometer (VSM) for 3 different mount orientations of the sample on the sample holder to explore the magnetic anisotropy. The samples printed in zero field exhibited a weak anisotropy with an easy axis perpendicular to the print direction. This anisotropy is caused by the effect of shear flow on the orientation of the magnetic platelets in the 3D printer head. For the MFAAM samples, the S values are largest along the print bed normal. This anisotropy is caused by the field. The alignment of the magnetic particles happens when the molten suspension is in the extruder. When the material is printed, it is folded over on the print bed and its easy axis rotates 90° parallel to the print bed normally. Little realignment of the particles happens after it is printed, suggesting a sharp drop in temperature once the composite touches the print bed, indicating that field-induced effects in the nozzle dominate the anisotropy of MFAAM deposited samples.
      PubDate: Mon, 12 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000791
      Issue No: Vol. 14, No. 2 (2024)
       
  • Apparent ferrimagnetism in Sr(Fe 0.2 Mn 0.2 Co 0.2 Ti 0.2 V 0.2 )O 3
           high-entropy oxide perovskite thin films

    • First page: 025023
      Abstract: We present a study on the structural and magnetic properties of Sr(Fe0.2Mn0.2Co0.2Ti0.2V0.2)O3 (S5BO) high-entropy oxide perovskite thin films. We use synchrotron-based x-ray absorption spectroscopy employing x-ray magnetic circular dichroism (XMCD) and reveal an enhanced presence of high-spin Co2+, which appears to feature a magnetic response opposing that of the two other magnetic transition metal elements, Fe and Mn. This is marked by both opposite XMCD signals and an inverted XMCD hysteresis loop for Co, while Fe and Mn show regularly shaped hysteresis curves, as the picture of a ferrimagnetic ground state emerges for S5BO.
      PubDate: Mon, 12 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0181333
      Issue No: Vol. 14, No. 2 (2024)
       
  • Design of directional transmission channel models for breast photoacoustic
           signals based on defect state structure

    • First page: 025024
      Abstract: In the photoacoustic detection of breast cancer, the weak intensity and severe energy attenuation of photoacoustic signals excited by the breast tissue become an important factor limiting the efficient acquisition of the ultrasound transducer. To overcome this problem, we proposed a linear defect channel and bifurcated acoustic transmission channel models at the front of the ultrasonic transducers based on the phononic crystal bandgap characteristics and defect state structure. The results of numerical analyses and simulations carried out using COMSOL demonstrated that the photoacoustic signal transmission channel proposed could confine the acoustic energy within the defects, while achieving the directional transmission and local enhancement of the acoustic field of high-frequency breast photoacoustic signals. This design effectively reduces the signal transmission loss and amplifies the mammographic signal intensity, which is conducive to efficient acquisition. In addition, the directional transmission effect is found to be strongly dependent on frequency, which makes the channel have great frequency selectivity. Through the flexible modulation of the transmission path of the artificial acoustic structure, breast photoacoustic signals of specific frequencies can be exported in separate paths to reduce the interference of noise signals. This study combines biomedical tumor detection with phononic crystals to present a novel method for efficient acquisition and deep detection of acoustic signals in tissue photoacoustic detection from the signal perspective, which is conducive to improving the sensitivity of breast cancer detection.
      PubDate: Wed, 14 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0186071
      Issue No: Vol. 14, No. 2 (2024)
       
  • Terahertz spectral characteristics of photosensitive resin based on
           microfluidic technology

    • First page: 025025
      Abstract: Photosensitive resin is a kind of polymer gel material. Due to its excellent UV curing performance, it is widely used in the emerging 3D printing industry. This article combines terahertz technology with microfluidic chip technology to study the terahertz spectral characteristics of liquid and solid photosensitive resins under different electric fields. In the experiment, it was found that an electric field can also cause polymerization of photosensitive resin monomers to form cross-linked polymers, increasing their curing degree. For solid photosensitive resins, the orientation of polymer molecules is enhanced under an electric field, and the molecular arrangement changes from a disordered state to an ordered state. Meanwhile, it was found that both liquid and solid photosensitive resins subjected to electric fields exhibit absorption coefficients below zero within a very small frequency range. We explain this from two aspects: energy and the Fabry Pérot effect. This article uses terahertz spectra to study the curing and structural changes in photosensitive resins under an electric field, laying a foundation for further improving 3D printing technology.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/7.0001316
      Issue No: Vol. 14, No. 2 (2024)
       
  • Superconductors and the periodic penetration parameter: Defining and
           utilizing in diverse applications

    • First page: 025026
      Abstract: There are various types of materials that have different levels of electrical conductivity, and one category is known as superconductors or superconducting materials. Superconducting materials are characterized by their complete lack of electrical resistivity. These materials are highly important due to their wide range of applications in electricity transmission, although they do have certain limitations. The Bardeen–Cooper–Schryver theory and the Ginzburg–Landau theory are two significant theories used to explain the nature of superconducting materials. Of particular interest in this study is the Ginzburg–Landau differential equation, which is considered a vital equation in this field. This equation belongs to a class of nonlinear differential equations. Our research focuses on simulating solutions to the Ginzburg–Landau equation under steady-state conditions. We conducted simulations for several superconducting materials, including aluminum, niobium, lead, tin, niobium germanide, niobium tin, vanadium silicate, lead hexa-molybdenum octa-sulfur, magnesium diboride, uranium triplatinum, potassium, barium copper oxide, yttrium, calcium copper oxide, and barium mercury. We define a new parameter of the superconductor conduction materials, which is the periodic parameter of the superconductor. By analyzing the periodic solutions obtained from the Ginzburg–Landau differential equation, we were able to determine the values of the periodic penetration parameters for each material. Notably, monatomic superconducting materials exhibited periodic penetration parameters in the range of tens of micrometers, while tetra- and penta-elements materials had values in the tens of nanometers. Superconducting materials of two or three different elements showed average values for these parameters. These findings provide valuable insights into the characteristics and behavior of various superconducting materials.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0186939
      Issue No: Vol. 14, No. 2 (2024)
       
  • Spin dynamics of room temperature van der Waals (vdW) ferromagnets and
           their usage in microwave devices

    • First page: 025027
      Abstract: Quasi-two-dimensional van der Waals (vdW) materials exhibiting room-temperature (RT) long-range ferromagnetic nature have emerged as a significant research field to explore fundamental condensed matter physics due to their intriguing physical properties. These vdW materials enable a futuristic platform for implementing novel spintronics devices. Here, we examined the spin dynamics of polycrystalline Fe5GeTe2 and Fe4.8Co0.2GeTe2 vdW materials using ferromagnetic resonance (FMR) spectroscopy. Vibrating Sample Magnetometer (VSM) study reveals that both materials have a soft ferromagnetic character at room temperature. From room temperature FMR measurements, the effective magnetization of Fe5GeTe2 and Fe4.8Co0.2GeTe2 derived ∼0.54 ± 0.056 and 0.50 ± 0.017 kOe, respectively. These results are consistent with reported VSM data. Fe5GeTe2 and Fe4.8Co0.2GeTe2 exhibit broad FMR linewidths of 0.697 ± 0.036 and 0.748 ± 0.056 kOe, respectively, which can be due to inhomogeneous line broadening. Besides its intrinsic contribution to linewidth, it is also affected by extrinsic Gilbert damping (αext). The value of αext is influenced by conflicting intra-band and inter-band electronic transitions, according to Modified Kambersky's theory. Furthermore, the effective Gilbert damping constant (α) obtained is 0.0513 ± 0.0046 for Fe5GeTe2 and 0.0526 ± 0.0031 for Fe4.8Co0.2GeTe2 at RT. Additionally, we developed microwave signal processing devices using these materials and evaluated their functionality both as a microwave band-reject filter and an adjustable phase shifter. The stop-band response was studied across the 5 to 25 GHz frequency range under an applied magnetic field as high as 7 kOe. For these flip-chip-based devices, attenuation is −5 dB/cm for the Fe5GeTe2-based filter and −3.2 dB/cm on sample Fe4.8Co0.2GeTe2 at 6.95 and 5.37 kOe, respectively. The same micro-strip filter was used as a tunable phase shifter in the off-resonance region. The optimal differential phase shift studied for Fe5GeTe2 and Fe4.8Co0.2GeTe2-based phase shifters in the high-frequency region (22 GHz for Fe5GeTe2 and 18 GHz for Fe4.8Co0.2GeTe2) is 23°/cm and 14°/cm, respectively, at high magnetic fields. These versatile devices find integration across a wide spectrum of applications, such as phased-array antennas, radar systems, and wireless communication systems, offering their benefits to diverse fields.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000786
      Issue No: Vol. 14, No. 2 (2024)
       
  • Luminous characteristics of high-voltage blue mini-light-emitting diodes

    • First page: 025028
      Abstract: The luminous characteristics of flip-chip type high-voltage (HV) blue mini-light-emitting diodes (LEDs), which consist of three serially connected sub-mesas, have been investigated for the first time. The cryogenic electroluminescence below 100 K partially originates from localized excitons. As the driving current reaches 1 μA, the contributions of Shockley–Read–Hall nonradiative recombination and radiative recombination exhibit a remarkably inverse temperature dependence, while the contributions of Auger recombination and carrier leakage are relatively negligible. The mesa corresponding to the anode of the HV blue mini-LED exhibits the lowest temperature among the three sub-mesas due to its smaller thermal resistance. To minimize the temperature-induced shift in chromaticity coordinates, it is necessary to adjust the driving current based on the operating temperature.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0180877
      Issue No: Vol. 14, No. 2 (2024)
       
  • Numerical simulation of void elimination in the billet during hot shape
           rolling processes based on the Gurson–Tvergaard–Needleman model

    • First page: 025029
      Abstract: The presence of voids can compromise the strength and continuity of downstream products. The Gurson–Tvergaard–Needleman model was utilized to obtain the relevant parameters. A 3D finite element model was then employed to investigate the elimination of voids in a porous free-cutting steel 1215MS during the hot shape rolling process. The center distribution of voids in the billet was considered in the finite element model, and the relationships between the void elimination and the pressure stress in the billet were analyzed. The influences of rolling reduction, rotation speed, and friction between the work roller and billet on the void elimination were also discussed. The results revealed that the pass reduction has a significant influence on the ultimate value of void volume fraction, which is beneficial for better material self-healing during the shape-rolling process. These findings suggest that accurate predictions of void elimination in the workpiece can be achieved using the finite element method for successful simulation of the hot shape rolling process.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0186700
      Issue No: Vol. 14, No. 2 (2024)
       
  • Towards fully electrically controlled domain-wall logic

    • First page: 025030
      Abstract: Utilizing magnetic tunnel junctions (MTJs) for write/read and fast spin-orbit-torque (SOT)-driven domain-wall (DW) motion for propagation, enables non-volatile logic and majority operations, representing a breakthrough in the implementation of nanoscale DW logic devices. Recently, current-driven DW logic gates have been demonstrated via magnetic imaging, where the Dzyaloshinskii-Moriya interaction (DMI) induces chiral coupling between perpendicular magnetic anisotropy (PMA) regions via an in-plane (IP) oriented region. However, full electrical operation of nanoscale DW logic requires electrical write/read operations and a method to pattern PMA and IP regions compatible with the fabrication of PMA MTJs. Here, we study the use of a Hybrid Free Layer (HFL) concept to combine an MTJ stack with DW motion materials, and He+ ion irradiation to convert the stack from PMA to IP. First, we investigate the free layer thickness dependence of 100-nm diameter HFL-MTJ devices and find an optimal CoFeB thickness, from 7 to 10 Å, providing high tunneling magnetoresistance (TMR) readout and efficient spin-transfer torque (STT) writing. We then show that high DMI materials, like Pt/Co, can be integrated into an MTJ stack via interlayer exchange coupling with the CoFeB free layer. In this design, DMI values suitable for SOT-driven DW motion are measured by asymmetric bubble expansion. Finally, we demonstrate that He+ irradiation reliably converts the coupled free layers from PMA to IP. These findings offer a path toward the integration of fully electrically controlled DW logic circuits.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000811
      Issue No: Vol. 14, No. 2 (2024)
       
  • Reversal of optical binding force on a plasmonic heterodimer with
           dipole–dipole type Fano resonance

    • First page: 025031
      Abstract: In the present work, we theoretically and numerically investigate the near field optical binding force on Au–Ag nanorod heterodimers, which can support the electrical dipole–dipole type Fano resonance, under a normally plane wave or polarized laser beam. The numerical results show that the optical binding force between the heterodimer can be reversed near the position of the Fano dip when the incident wave is polarized along the dimer axis, indicating an attractive to repulsive transition. Compared with the Au–Ag heterodimer, the Au and Ag homodimers with the same material show no repulsive binding force. Using the multipole decomposition method, we find that the sign of optical binding force is completely determined by the phase difference of the separated electric dipole plasmon modes excited in the different particles, which can be strongly affected by the wavelength of the incident wave. In addition, we demonstrate the effects of three geometrical parameters (including the length, radius, and gap of the heterodimer) on the Fano-mediated optical binding force in detail. Finally, the numerical results indicate that the reversal of attractive and repulsive forces can also be obtained when the heterodimer is illuminated with a laser beam. Our findings are important for not only a deep understanding of plasmonic-mediated optical binding force but also stable optical manipulation of the plasmonic particles.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0185916
      Issue No: Vol. 14, No. 2 (2024)
       
  • Analysis of factors influencing electric energy measurement in power
           systems

    • First page: 025032
      Abstract: This article focuses on summarizing and analyzing the causes of errors in electric energy meters under harmonic conditions, clarifying the relationship between errors and frequency characteristic curves, and pointing out that the positive and negative errors mainly depend on the direction of each harmonic power relative to the fundamental power, the properties of the load, the differences in physical properties of electric energy meter manufacturing and material formation, etc.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0190948
      Issue No: Vol. 14, No. 2 (2024)
       
  • Low-temperature Raman studies of graphene oxide: Analysis of structural
           properties

    • First page: 025033
      Abstract: This work is devoted to the low-temperature Raman studies of a bright representative of 2D materials—graphene oxide (GO) film in the range of 5–325 K. The performed analysis of the temperature evolution of the peak positions as well as linewidths of two Raman modes D (∼1300 cm−1) and G (∼1600 cm−1) was described in terms of the anharmonic model. The temperature behavior of the G mode demonstrated a slight deviation from the anharmonic model below ∼50 K in contrast to the D mode, which could be explained by involving an additional phonon decay channel. The analysis of the linewidth of the Raman modes showed that the distribution of defects in GO is inhomogeneous and surface functionalization effectively separates neighboring layers. The average value of the distance between defects and the defect density was estimated. The obtained results can be useful for understanding phonon dynamics for the development of nanodevices based on 2D materials where confinement of propagation of phonon excitations plays a key role.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0188838
      Issue No: Vol. 14, No. 2 (2024)
       
  • Non-enzymatic electrochemical sensor based on ZnO nanoparticles/porous
           graphene for the detection of hypoxanthine in pork meat

    • First page: 025034
      Abstract: In this study, we developed a pioneering non-enzymatic electrochemical sensor utilizing a flexible porous graphene electrode modified with ZnO nanoparticles (ZnO/fPGE sensor) to assess hypoxanthine (HXA) content in pork at post-mortem time. The ZnO/fPGE sensor was synthesized via hydrothermal method and direct laser writing with a CO2 laser on a polyimide film at ambient conditions. Its characterization was analyzed by Raman, Fourier-transform infrared spectroscopy, field-emission scanning microscopy, energy-dispersive x-ray spectroscopy, and cyclic voltammetric techniques. Linear response, the limit of detection, and sensitivity to the HXA were enhanced with the values of the range from 1.5 to 150, 0.14 µM, and 6.6 µA μM−1 cm−2, respectively. Effective resistance to common physiological interferences (such as uric acid, ascorbic acid, dopamine, glucose, and xanthine) was indicated, and additionally, the determination of HXA concentration in real samples with good selectivity is attributed to the synergistic effects between ZnO nanoparticles and fPGE. Therefore, the ZnO/fPGE has provided a favorable electrical environment for developing high-performance electrochemical biosensors to determine hypoxanthine in pork meat.
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0190293
      Issue No: Vol. 14, No. 2 (2024)
       
  • Exploring the critical behavior of the anomalous spin-glass transition in
           Ga 1− x Mn x S

    • First page: 025035
      Abstract: Single-crystalline Ga1−xMnxS is a quasi-two-dimensional system that exhibits an anomalous spin-glass transition temperature compared with the other well-known spin-glass systems. In contrast to the other known spin-glasses that all have three-dimensional structures, our host chalcogenide GaS system is quasi-two-dimensional. Recent interest in utilizing spin-glass materials for applications in short-term, low-energy memory and processing power make this new 2-D system important for further exploration. We report on the critical behavior of the anomalous spin-glass transition in a single-crystalline Ga0.91Mn0.09S system. Using the scaling equation of state describing the spin-glass transition in Ga1−xMnxS, we obtained the relation χnl = C1H2/δ and extract the value δ = 5.5 ± 0.5 for this critical exponent as well as a value of ϕ = 4.8 for another critical exponent. We find this value of delta for the critical temperature Tc = 11.2 K, combined with the other critical exponents γ = 4.0 and β = 0.8 form a self-consistent description of the spin-glass transition in this unusual 2-D spin-glass system. Interestingly, these results represent convincing evidence that, despite Ga1−xMnxS having a quasi-two-dimensional structure, Ga1−xMnxS undergoes a true spin-glass transition and is related to the class of semiconducting spin-glass materials with short-range interactions. The spin-glass transition in Ga1−xMnxS is characterized by critical exponents similar to the three-dimensional spin-glass systems.
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000832
      Issue No: Vol. 14, No. 2 (2024)
       
  • On the physical meaning of the geometric factor and the effective
           thickness in the Montgomery method

    • First page: 025036
      Abstract: The Montgomery method is extensively employed to determine the electrical resistance tensor of anisotropic samples. This technique relies on two essential parameters describing an isotropic system: the geometric factor (H1) and the effective thickness (E). The numerical values of these parameters are intricately linked to the dimensions of an isotropic block equivalent to the studied anisotropic specimen. While these parameters hold importance, the physical interpretation of these terms still lacks clarity. In this study, we utilized the finite element method to simulate electrical transport experiments across samples of various shapes. Utilizing the Electric Currents physics interface in the COMSOL program, we were able to provide a comprehensive analysis of the physical meaning of these parameters to accurately determine the electrical properties of thin films and wafers. The presented findings related to the physical interpretation of H1 and E terms make substantial contributions to the field of electrical transport experimental techniques, which are fundamental to design advanced materials for technological applications and understand their physical properties.
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0156453
      Issue No: Vol. 14, No. 2 (2024)
       
  • Advancements in neural network techniques for electric and magnetic field
           reconstruction: Application to ion radiography

    • First page: 025037
      Abstract: In the realm of high-energy-density laboratory plasma experiments, ion radiography is a vital tool for measuring electromagnetic fields. Leveraging the deflection of injected protons, ion imaging can reveal the intricate patterns of electromagnetic fields within the plasma. However, the complex task of reconstructing electromagnetic fields within the plasma system from ion images presents a formidable challenge. In response, we propose the application of neural network techniques to facilitate electromagnetic field reconstructions. For the training data, we generate corresponding particle data on ion radiography with diverse field profiles in the plasma system, drawing from analytical solutions of charged particle motions and test-particle simulations. With these training data, our expectation is that the developed neural network can assimilate information from ion radiography and accurately predict the corresponding field profiles. In this study, our primary emphasis is on developing these techniques within the context of the simplest setups, specifically uniform (single-layer) or two-layer systems. We begin by examining systems with only electric or magnetic fields and subsequently extend our exploration to systems with combined electromagnetic fields. Our findings demonstrate the viability of employing neural networks for electromagnetic field reconstructions. In all the presented scenarios, the correlation coefficients between the actual and neural network-predicted values consistently reach 0.99. We have also learned that physics concepts can help us understand the weaknesses in neural network performance and identify directions for improvement.
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189878
      Issue No: Vol. 14, No. 2 (2024)
       
  • Experimental study on subwavelength focusing optical field detection
           methods for micro-Fresnel zone plate

    • First page: 025038
      Abstract: In this paper, the detection methods and detection systems for the subwavelength focusing optical field of the micro-Fresnel zone plate (FZP) are experimentally studied. First, a comparison is made between the micro/nanofabrication methods for micro-FZP, namely, focused ion beam (FIB) and electron beam lithography, and the results show that FIB is better suited for the amplitude-type micro-FZP fabrication. Subsequently, the experimental detection devices based on the wide-field microscopy amplification (WFMA) imaging method (indirect detection method) and scanning near-field optical microscopy (direct detection method) are, respectively, constructed for the detection of the subwavelength focusing optical field of micro-FZP. The experimental results are compared and analyzed with theoretical calculation results, indicating that the WFMA method is more suitable for the detection of micro-FZP subwavelength focusing optical field that is not sensitive to radial components. This study provides an experimental reference for the micro/nanofocusing optical field detection of micro/nano-optical components similar to micro-FZP and promotes the practical application of micro-FZP.
      PubDate: Wed, 21 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0193428
      Issue No: Vol. 14, No. 2 (2024)
       
  • A miniaturized-slotted planar MIMO antenna with switchable configuration
           for dual-/triple-band notches

    • First page: 025039
      Abstract: This paper outlines the design and validation of a four-port compact Multi-Input Multi-Output (MIMO) antenna engineered to provide reconfigurable band notches within the ultra-wideband spectrum. The antenna features a circular monopole engraved with split ring slots along its radiating section, while a U-shaped slot is etched onto the feed line to facilitate band notches at specific frequencies—4.3 GHz (corresponding to INSAT), 6.8 GHz (aligned with Wi-Fi-6E), and 8.3 GHz (pertaining to X-band satellite). To ensure proper isolation, the MIMO elements are arranged orthogonally, and a decoupling periodic structure is strategically interposed between these elements to enhance isolation further. The incorporation of a PIN diode within the U-shaped slot introduces reconfigurability into the band notching mechanism. The MIMO antenna operates in two distinct modes depending upon the state of the PIN diode, either activated (ON) or deactivated (OFF). In the former mode, the antenna offers switchable band notches across three frequencies, while in the latter mode, it offers band notches at two specific frequencies. The validity of the antenna’s performance is validated through real-time fabrication and measurement. Both simulated and measured results exhibit a notable correlation. The antenna stands as an appropriate candidate for future cognitive radio applications.
      PubDate: Wed, 21 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0190950
      Issue No: Vol. 14, No. 2 (2024)
       
  • Characterization of carbon-coated core-shell iron nanoparticles annealed
           by oxygen and nitrogen

    • First page: 025040
      Abstract: Nanocomposites consisting of nanoparticles of iron oxide (Fe3O4) and iron carbide (Fe3C) with a core-shell structure (Fe core, Fe3O4 and/or Fe3C shells) coated with additional graphite-like carbon layer dispersed in carbon matrix have been synthesized by solid-phase pyrolysis of iron-phthalocyanine (FePc) and iron-porphyrin (FePr) with a pyrolysis temperature of 900°C, and post-annealing conducted at temperatures ranging from 150°C to 550°C under controlled oxygen- and/or nitrogen-rich environments. A comprehensive analysis of the samples’ morphology, composition, structure, size, and magnetic characteristics was performed by utilizing scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-STEM) with elemental mapping, X-ray diffraction analysis (XRD), and magnetic measurements by utilizing vibrating sample magnetometry (VSM). The effect of the annealing process on magnetic performance and efficient control of the hysteresis loop and specific absorption rate (SAR) are discussed.
      PubDate: Thu, 22 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000845
      Issue No: Vol. 14, No. 2 (2024)
       
  • Spin glass state in Co doped NdMnO 3

    • First page: 025041
      Abstract: The temperature-dependent ac susceptibility studies of in-phase component (χ′ac) and out of phase component (χac″) was done on a single phase polycrystalline NdMn0.6Co0.4O3 sample. The measurements were conducted in 4 Oe ac field and 0 Oe dc field at frequencies of 111, 311, 1011, and 1311 Hz. As the frequency increases, the magnitude of χ′ac decreases, and its peak position, corresponding to Tf, moves towards higher temperatures. This strongly suggests the presence of a spin glass (SG) state and the absence of long-range ferromagnetic ordering. The value of relative shift in freezing temperature (δTf) is found to be δTf = 0.0089, which suggests the existence of canonical SG state in NdMn0.6Co0.4O3 sample. To confirm it the ac susceptibility data was further analyzed using Arrhenius, Vogel Fulcher, and Power–law.
      PubDate: Fri, 23 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000810
      Issue No: Vol. 14, No. 2 (2024)
       
  • On the feed-forward neural network for analyzing pantograph equations

    • First page: 025042
      Abstract: Ordinary differential equations (ODEs) are fundamental tools for modeling and understanding a wide range of chemistry, physics, and biological phenomena. However, solving complex ODEs often presents significant challenges, necessitating advanced numerical approaches beyond traditional analytical techniques. Thus, a novel machine learning (ML)-based method for solving and analyzing ODEs is proposed in the current investigation. In this study, we utilize a feed-forward neural network (FNN) with five fully connected layers trained on data samples generated from the exact solutions of specific ODEs. To show the efficacy of our suggested method, we will conduct a thorough evaluation by comparing the anticipated solutions of the FNN with the exact solutions for some ODEs. Furthermore, we analyze the absolute error and present the loss functions for some ODE examples, providing valuable insights into the model’s performance and potential areas for further development.
      PubDate: Fri, 23 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0195270
      Issue No: Vol. 14, No. 2 (2024)
       
  • Comparison of excitation temperature of a laser-produced plasma by
           combining emission and absorption spectroscopy

    • First page: 025043
      Abstract: Measurement of the temporal evolution of laser-produced plasma temperature is very important for many of its applications, and several plasma diagnostic tools are routinely used by researchers. However, it is very challenging to measure the properties of the plasma at the early and late times of its evolution using a single diagnostic tool. In this study, we combined emission and laser absorption spectroscopy to compare the excitation temperatures of a laser-produced uranium plasma system. Several U I transitions in the near-infrared spectral range (775–800 nm) were considered, and the Boltzmann plot method was used to measure the excitation temperatures using both emission and absorption spectroscopy. Emission spectroscopy provided early-time temperature measurements of the plasma up to times 2–20 µs, while absorption spectroscopy provided temperature measurements at late times of plasma evolution (for times 5–80 µs). The emission and absorbance of U I transitions were found to follow the Boltzmann distribution, indicating the plasma is likely in the state of local thermodynamic equilibrium even at late times of its lifetime. The emission and absorption-based time-resolved excitation temperatures demonstrated good agreement at earlier times (≤15 µs) in the overlapped temporal region, while a deviation in the measured values was seen at times (≥15 µs), and potential reasons for such a disagreement are discussed.
      PubDate: Mon, 26 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0190522
      Issue No: Vol. 14, No. 2 (2024)
       
  • An efficiently excited Eu 3+ luminescent site formed in Eu,O-codoped GaN

    • First page: 025044
      Abstract: For the development of III-nitride-semiconductor-based monolithic micro-light-emitting diode (LED) displays, Eu,O-codoped GaN (GaN:Eu,O) is a promising material candidate for the red LEDs. The luminescence efficiency of Eu-related emission strongly depends on the local atomic structure of Eu ions. Our previous research has revealed that post-growth thermal annealing is an effective method for reconfiguring luminescent sites, leading to a significant increase in light output. We observed the preferential formation of a site with a peak at ∼2.004 eV by the annealing process. In this study, we demonstrate that it is a previously unidentified independent site (OMVPE-X) using combined excitation–emission spectroscopy and time-resolved photoluminescence measurements. In addition, we perform excitation power-dependent photoluminescence measurements and show that this OMVPE-X site dominates the emission at a low excitation power region despite its small relative abundance, suggesting a high excitation efficiency. Most importantly, applying our annealing technique to an LED exhibits a reasonably increased electroluminescence intensity associated with OMVPE-X, confirming that this site has a high excitation efficiency also under current injection. These results demonstrate the importance of OMVPE-X as a notable luminescent site for brighter and more efficient GaN:Eu,O-based LEDs.
      PubDate: Tue, 27 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0183774
      Issue No: Vol. 14, No. 2 (2024)
       
  • Study on the effect of magnetic needle grinding process on the service
           properties of medical Mg-1.6Ca-2.0Zn alloy

    • First page: 025045
      Abstract: Magnesium alloy, valued for its superior mechanical properties and biocompatibility in biomaterials, faces limitations such as rapid corrosion, poor wear resistance, and unfavorable cell adhesion. To address these challenges and enhance medical magnesium alloy development, this study investigates a magnetic needle grinding process on magnesium alloy. Mg-1.6Ca-2.0Zn alloy, prepared through powder metallurgy and T6 aging treatment, undergoes milling, and magnetic grinding using various needle sizes. The impact is assessed through Vickers hardness, residual stresses, surface roughness, friction and wear tests, electrochemical assessments, and contact angle tests. Results indicate a 22.59% microhardness increase, 30.43 MPa residual compressive stress, increased surface roughness, improved wear and corrosion resistance, and improved hydrophilia after magnetic needle grinding. This research provides a theoretical foundation for advancing medical magnesium alloy industrially.
      PubDate: Tue, 27 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0195553
      Issue No: Vol. 14, No. 2 (2024)
       
  • Synthesis of nano-selenium and its effects on germination and early
           seedling growth of four crop plants

    • First page: 025046
      Abstract: In this work, nano-selenium (NSe) with different shapes (wires, rods, and spherical particles) was synthesized by a wet chemical method. These synthesized products were characterized by x-ray powder diffraction (XRD) analysis, a field emission scanning electron microscope (FE-SEM) with an energy dispersive x-ray analyzer, and Raman spectroscopy. FE-SEM images revealed that nanowires with an average diameter of 30–50 nm and length of 3–5 µm, nanorods with lengths of 400–800 nm and diameters of about 20–50 nm, and spherical-shaped nanoparticles (NPs) with diameters ranging from 40 to 60 nm were successfully synthesized. The XRD and Raman analysis confirmed that all the produced NSe samples exhibited hexagonal single-phase crystalline structure with no impurity phase. All three NSe products (SeNWs, SeNRs, and SeNPs) with a concentration range of 25–150 mg/l were used to investigate the impact of shape and concentration on seed germination and seedling vigor of four different crop species, namely, green bean, okra, wheat, and radish. The results revealed that NSe at low concentrations (≤50 mg/l for SeNWs and ≤100 mg/l for SeNRs and SeNPs) can promote seed germination, plant growth, and development of all the studied crop species. However, NSe can adversely affect the growth of plants at higher concentrations (≥75 mg/l for SeNWs).
      PubDate: Wed, 28 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0188848
      Issue No: Vol. 14, No. 2 (2024)
       
  • Layered carbon nitride films deposited under an oxygen-containing
           atmosphere and their electronic properties

    • First page: 025047
      Abstract: Layered carbon nitride (g-C3N4) is a novel semiconducting and functional material for optoelectronic applications. The physical and chemical properties of g-C3N4 films differ depending on the preparation atmosphere. Herein, we deposited g-C3N4 films under a mixed oxygen (O2)-nitrogen (N2) gas atmosphere and studied their effects on the carrier transport properties. Although no significant change in the film orientation was observed, the deposition rate decreased as the O2 gas ratio in the mixed N2/O2 atmosphere increased. Despite their thinness, the luminescence intensity of g-C3N4 films deposited under an O2-containing atmosphere increased by 3.5–5.0 times compared to that deposited under an N2 atmosphere. With respect to voltage application, carrier transport owing to the thermionic emission and/or direct tunneling initially followed ohmic conduction, followed by insufficient trap-filled conduction. As the applied voltage increased further, fully trap-filled conduction was confirmed owing to Fowler–Nordheim tunneling. Moreover, the conductivity type could be changed to p-type and n-type using N2 gas and mixed N2/O2 gas atmospheres, respectively, during film deposition. In addition to the intrinsic transport properties, the intentionally formed Schottky barrier also affected the carrier transport; therefore, the diode-like rectifying behavior of the current density was achieved.
      PubDate: Wed, 28 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0193419
      Issue No: Vol. 14, No. 2 (2024)
       
  • Short rise- and decay-time Z-pinch currents for soft x-ray laser
           excitation

    • First page: 025048
      Abstract: The article addresses how to create inductance-free plasma and use it to excite soft x-ray lasers. The method employs a bifilar phenomenon in which one part of the pulsed current flows via the plasma column while the other part runs in the opposite direction via the closely placed external conductor. The electromagnetic fields formed by the plasma and return conductor are adjusted by lowering the distance between them to neutralize the magnetic field of the bifilar. Because the net transient magnetic field is drastically reduced, the plasma-conductor mutual inductance is near zero during current rise and decay. The inductance-free (L ∼ 2 nH) 35 cm-long Z pinches in a 3.1 mm-diameter argon-filled alumina capillary with current rise and decay times of 15 ns, dI/dt > 1012 A/s, and amplitudes up to 17 kA were predicted, realized, and verified to be suitable for pumping soft x-ray Ar+8 lasers. Without the bifilar phenomenon, the 35 cm Z pinches obey a 200 nH inductance that restricts the rise and decay durations of currents to 150 ns. The 35 cm Z pinches with 2 nH inductance generated 46.9 nm laser pulses with up to 4 μJ of energy and a beam divergence of 2 mrad at a low operating voltage of 35–45 kV, compared to 0.1–0.8 MV for similar lasers. The bifilar method could find applications in many research and technological fields, where the rise and decay times of discharge currents play a key role.
      PubDate: Wed, 28 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0191533
      Issue No: Vol. 14, No. 2 (2024)
       
  • Enhanced orbital magnetic moment of Co film grown on Fe 3 O 4 (001)

    • First page: 025049
      Abstract: We investigate the magnetic and electronic properties of Co films on Fe3O4(001) achieved through epitaxial growth using magnetron sputtering. X-ray magnetic circularly dichroism measurements characterize the atomic magnetism. Compared to Co films on the MgO substrate, Co on Fe3O4 exhibits a 96% enhancement in orbital magnetic moment (from 0.25 to 0.49 µB/atom) and an increase in spin magnetic moment (from 1.37 to 1.53 µB/atom), resulting in an increased mratio(ml/ms) from 0.18 to 0.32. This enhancement of the orbital moment emerges as a consequence of the interface interaction between Co and Fe3O4. Density functional theory calculations attribute this heightened orbital magnetic moment to the robust electronic exchange interactions. Our findings not only offer insights into the modulation of magnetic and electronic characteristics in Co-based magnetic heterostructures but also provide valuable implications for the potential application of magnetic oxide/ferromagnetic heterostructures in future spintronic devices.
      PubDate: Wed, 28 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0176740
      Issue No: Vol. 14, No. 2 (2024)
       
  • Multifunctional platform for photothermal therapy combined with
           luminescence nanothermometry probes

    • First page: 025101
      Abstract: The design of multifunctional magnetic nanoparticles (NPs) that can generate and monitor heat release in real-time during thermal therapy is a major challenge in nanomedicine. In this work, a trimodal system that combines magnetic hyperthermia (MH), photothermal therapy (PT) and luminescence nano-thermometry (LT) has been set up in a single platform. Magnetite NPs were optimized focusing on MH and PT; then, the NPs have been coated with embedded Nd3+ cations to enhance the PT and to act as LT probe. Nd3+ is an interesting luminescent probe, with excitation around 800 nm and emission at the second biological window. Such hybrid system could act as heat mediator and imaging probe for in situ thermometer during the PT and MH, since these wavelengths belong to the biological windows.
      PubDate: Thu, 01 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000729
      Issue No: Vol. 14, No. 2 (2024)
       
  • Suppression of in-plane (001) texture component in FePt-oxide granular
           films by adding a carbon buffer layer

    • First page: 025102
      Abstract: Investigation of magnetic properties and nanostructure of FePt-B2O3 granular film with carbon buffer layer (BL) of various thicknesses is reported. When the thickness of carbon BL is varied from 0 to 0.6 nm, saturation magnetization (Msfilm) is almost constant at around 750 emu/cm3 and perpendicular magnetic anisotropy (Ku⊥film) changes from around 1.0×107 to 2.0×107 erg/cm3. For the granular film with the carbon BL thicker than 0.6 nm, both Msfilm and Ku⊥film decrease. The reduction of Msfilm for the granular film by adding a carbon BL may be due to the alloying of carbon into the FePt magnetic grains. The enhancement of Ku⊥film for the film with a 0.6 nm carbon BL is considered due to the reduction of the in-plane texture component which is supported by the in-plane XRD. The reduction of Ku⊥film for the film with a carbon BL thicker than 0.6 nm is considered due to random growth of magnetic grains on a continuous carbon BL which is supported by the TEM cross-section images. According to these results, the employment of an un-continuous thin carbon BL is a promising method to enhance c-axis texture orientation of the FePt-oxide granular films.
      PubDate: Thu, 01 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000752
      Issue No: Vol. 14, No. 2 (2024)
       
  • Analysis of magnetostriction of oriented silicon steel under motor
           magnetic field

    • First page: 025103
      Abstract: The performance requirements of motors are gradually increasing, and anisotropic soft magnetic materials have been applied in motors to improve performance, The magnetostriction of anisotropic soft magnetic materials is one of the main contributors in extensive research on anisotropic soft magnetic material transformers. Compared to transformers, the magnetic field in motors has more complex harmonic and multi-directional characteristics. In this paper, the magnetic field of motors stator teeth under both no-load and load conditions is calculated and analyzed to research magnetostriction of anisotropic soft magnetic materials in motor magnetic field and predict the NVH performance of anisotropic soft magnetic material motors accurately. Furthermore, the magnetostriction in different magnetization angles is investigated for the multi-directional characteristics, and the result is explained from microscopic principles. This paper focuses on a splicing oriented silicon steel (OSS) motor, the magnetization angle of OSS in motor varying from 0° to 90°. Firstly, the equivalent formulas of magnetic field are obtained under the analytical and finite element calculations. After that, the frequency and direction of experiment magnetic field are confirmed and the magnetostriction of OSS in different magnetization angle and frequency is measured. In the end, the variation character of magnetostriction of OSS is summarized.
      PubDate: Thu, 01 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000759
      Issue No: Vol. 14, No. 2 (2024)
       
  • Influence of surface acoustic wave (SAW) on nanoscale in-plane magnetic
           tunnel junctions

    • First page: 025104
      Abstract: The use of voltage induced strain to switch magnetic tunnel junctions (MTJs) is a promising solution for reducing the switching energy in MRAM technologies. The MTJ is integrated with a piezoelectric layer to generate the strain. A very thin layer is needed to switch with small voltages and small energy dissipation. It is challenging to synthesize ultrathin piezoelectric layers that retain a high degree of piezoelectricity. An alternate approach is to use time-varying strain generated by a surface acoustic wave (SAW). This approach does not require a thin piezoelectric layer since the SAW is confined to the surface of the layer. In this study, we fabricated in-plane MTJs on piezoelectric LiNbO3 substrates and used IDTs to generate the SAW signal within the substrate. Our results showed that the SAW signal had a significant influence on the resistance and the tunneling magnetoresistance (TMR) ratio of the MTJs. The influence was much less significant in nanometer size MTJs than in micrometer sized ones. Most surprisingly, the SAW signal caused the tunneling magnetoresistance ratio (TMR) to drop below zero for the micrometer size MTJ, meaning that the antiparallel resistance RAP is temporarily less than the parallel resistance RP under SAW excitation. Our results provide insight into the dynamic behavior of MTJs under periodic strain and the dependence of this behavior on the device dimensions as they are scaled down to nanometer sizes.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000823
      Issue No: Vol. 14, No. 2 (2024)
       
  • Repulsive magnetic levitation-based electromagnetic energy harvesting of a
           low-frequency ocean wave

    • First page: 025105
      Abstract: In this study, an electromagnetic energy harvester for a low-frequency ocean wave was developed in a compact 3D-printed structure. Ocean wave energy conversion technologies exist, but maintaining them in the harsh marine environment is crucial for business. Friction increases maintenance costs. Therefore, magnetic levitation, being friction-free, is used for cost-effective, low-maintenance electromagnetic energy harvesting applications. Low-frequency oscillating energy is captured using repulsive magnetic levitation with a buoy and generating electricity using a permanent magnet and copper coil. A levitating magnet is repelled by a fixed one, inducing electricity as it passes through a coil. Experiments with a 0.1 Hz sine wave mimic the average frequency of ocean waves, showing successful voltage peaks at intervals. The output voltage and measured power from the harvester exhibit variations influenced by multiple parameters. The maximum output voltage observed was 3.4 V and an average of 99 mW of power was calculated. The experiment demonstrates the feasibility of using repulsive magnetic levitation for low-frequency wave energy harvesting and also encompasses various harvester configurations, including transfer magnet forces and top magnets.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000826
      Issue No: Vol. 14, No. 2 (2024)
       
  • Winding-MMF-based design and investigation of dual-winding hybrid-tooth
           vernier permanent magnet motor with reduced torque ripple and improved
           power factor

    • First page: 025106
      Abstract: In this paper, in order to further reduce torque ripple and improve power factor, a new vernier permanent magnet motor is proposed, in which the design concept of dual-winding hybrid-tooth configuration is incorporated. In order to clarify motor torque ripple and power factor, the winding-magnetomotive-force-based design and analysis method is proposed, in which harmonic characteristics are considered as key factors during the magnetic field modulation process. The relationship between harmonics generated by winding MMF, torque ripple, and power factor are investigated. In addition, the split-tooth vernier permanent magnet motor is also investigated as a referenced motor. Detailed comparisons between the DWHT-VPM motor and ST-VPM motor are carried out, including air gap magnetic field, torque, and power factor. Both theoretical and simulation results verify the reasonability of the proposed DWHT-VPM motor, and the effectiveness of the proposed winding-MMF-based analysis method, which provide a new potential research path for the design and analysis of flux modulation motors.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000785
      Issue No: Vol. 14, No. 2 (2024)
       
  • Sedimentation evaluation of high-viscosity linear polysiloxane-based
           magnetorheological fluids using automated vertical axis inductance
           monitoring system

    • First page: 025107
      Abstract: The sedimentation evaluation of magnetorheological fluids (MRFs) is a key component to developing successful commercial MRF-based engineering applications. In this study, the long-term sedimentation stability of highly stable high-viscosity linear polysiloxane-based MRFs (HVLP MRFs) was experimentally investigated by using an automated vertical axis inductance monitoring system (AVAIMS). The sedimentation evaluation of the HVLP MRFs with high particle loadings up to 45 vol% was tracked for 295 days, and the four different sedimentation zones such as supernatant, original concentration, variable concentration, and sediment were identified. To this end, the automated identification method to determine the sedimentation zone boundaries of highly stable MRFs was proposed. Three HVLP MRF samples with two different high particle loadings of 35 vol% and 45 vol% and two different high carrier viscosities of 5k and 10k cSt were selected as testing samples and one commercial MRF with a particle loading of 40 vol% (i.e., LORD MRF-140CG) also was tested as a baseline.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000769
      Issue No: Vol. 14, No. 2 (2024)
       
  • Integration of fiber tracts in anatomically accurate brain models during
           transcranial magnetic stimulation

    • First page: 025108
      Abstract: Transcranial magnetic stimulation (TMS) is a noninvasive brain stimulation technique used in the treatment of several neurological conditions. The dosage parameter for TMS protocols is the resting motor threshold (RMT) which has been shown to vary between participants with limited understanding. The goal of this study was to investigate how white matter-derived fiber tracts integrated into finite element analysis simulations influence TMS response in the form of RMT. Ten healthy participants were included in this study who underwent TMS, diffusion tensor imaging, and structural magnetic resonance imaging. Anatomically accurate head models were created, and fiber tracts were extracted from Diffusion tensor imaging and integrated into these head models before finite element analysis simulations were performed to model the effects of empirical TMS. Linear mixed effects models were used to evaluate how the induced electric field strength on the fiber tracts (EFSTract) influenced RMT. We found the induced electric field strength along fiber tracts did influence RMT, however the effect of this relationship on RMT is not clinically relevant due to its small magnitude. This suggests finite element analysis of the fiber tracts is not meaningful when tracts are considered a homogenous material and thus lacking physiology. However, tractography provides a valuable framework within which to organize physiological models of signal transmission, and it is likely a combination of this approach with more physiologically detailed modeling would provide more accurate RMT prediction.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000817
      Issue No: Vol. 14, No. 2 (2024)
       
  • Optimization method of a magnetic field generating a magnetic force field
           for magnetic nanoparticle control

    • First page: 025109
      Abstract: We present a novel method for estimating the magnetic field that can generate the desired magnetic force to move magnetic nanoparticles in a region of interest. The magnetic field is expanded using vector spherical harmonics, and the optimal multipole moments are estimated. The multipole moments are included in quadratic form because the magnetic force is defined as the product of the magnetic field and its gradient. We transform the system of quadratic equations into a rank-one-matrix estimation problem to construct a convex numerical algorithm based on a well-established proximal operation. The proposed method was validated using numerical simulations and can be used to design magnetic force patterns that cannot be generated using a simple coil pair.
      PubDate: Tue, 06 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000746
      Issue No: Vol. 14, No. 2 (2024)
       
  • Equilibrium and locomotion characteristics of multi-modular magnetic
           millirobots with different magnet patterns

    • First page: 025110
      Abstract: This paper investigated a multi-modular magnetic microrobot/millirobot (MMM) with a serial chain structure consisting of multiple identical modules. Depending on the magnet pattern used for the MMM’s modules, an MMM can have different equilibrium postures under an external magnetic field, such as assembled ring and disassembled straight-line postures. In this study, we investigated the equilibrium and locomotion characteristics of the MMM by applying two different representative magnet patterns, considered to be effective for magnetic actuation, to the robots. We established various equations to determine and control the assembly, disassembly, and locomotion of the MMM with each magnet pattern. We also conducted various experiments demonstrating the assembly, disassembly, and cargo delivery capabilities of the MMM under different external magnetic fields. Results confirmed that each MMM and their magnet pattern have distinctive and useful characteristics, demonstrating that the two magnet patterns can be selectively and effectively used as MMM in different applications.
      PubDate: Tue, 06 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000846
      Issue No: Vol. 14, No. 2 (2024)
       
  • Characterization of microbubble aggregation in a double-T microfluidic
           chip

    • First page: 025111
      Abstract: The coalescence phenomenon of air bubbles affects the flow field, bubble morphology, bubble velocity, and mass transfer efficiency in bioreactors, air bubble generators, and other devices. This article combines the level set method with COMSOL to simulate the formation process of two-phase fluid bubbles in microfluidic chips. The result shows that when the contact angle exceeds 90°, significant agglomeration occurs and the size of bubbles decreases with the increase in liquid flow velocity. However, as the gas velocity increases, agglomeration does not occur at liquid flow rates below 0.1 m/s. In addition, the agglomeration phenomenon occurs above the threshold, and when the gas flow rate is less than 0.02 m/s, there is no agglomeration phenomenon. The numerical simulation results exhibit an error rate of less than 10% compared to the experimental values, indicating that microfluidic chips can accurately predict the process of bubble coalescence.
      PubDate: Tue, 06 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189836
      Issue No: Vol. 14, No. 2 (2024)
       
  • Measurement of magnetic properties of grain-oriented electrical steel
           considering multi-physics factors influence

    • First page: 025112
      Abstract: The magnetic properties of electrical steel sheets are strongly affected by the Multi-Physics Factors (MPF), such as bending stress, working temperature, and magnetization patterns. To investigate the complex magnetic properties of the material under MPF magnetizing conditions, a magnetic property measurement system is first developed, considering the effect of bending stress, temperature loading, and non-sinusoidal magnetization waveforms. Then, the magnetic and the loss properties of Grain-Oriented (GO) electrical steels under MPF magnetizing conditions are measured and discussed. Obtained results showed that bending stress and non-sinusoidal magnetization waveforms are positively correlated with the loss properties of electrical steel sheets, and elevated temperatures can mitigate the effects of bending stress and harmonics on magnetic properties and losses.
      PubDate: Wed, 07 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000745
      Issue No: Vol. 14, No. 2 (2024)
       
  • Fe-based amorphous powder cores with low core loss and improvement of
           permeability

    • First page: 025113
      Abstract: Fe-based amorphous powder cores of Fe–Si–B–Cr–C magnetic powder and phenolic binder were fabricated, and the effects of annealing and compaction pressure on the soft magnetic properties and core loss were investigated. The formation of Fe–B and α-Fe (Si) phases was confirmed at the annealing temperature above 773 K. The density gradually increased from 5.3 to 5.5 g/cm3 as annealing temperature increased, resulting in the saturation magnetization 4πMs increased to 1.0 T at 773 K. The effect of compaction pressure was studied by using samples annealed at 723 K. Both the density and 4πMs enhanced with compaction pressure from 980 to 1960 MPa. The real part of permeability µ’ remained constant for the frequency up to 2 MHz. The initial value of µ’ increased from 25 to 38 with compaction pressure. Consequently, at Bm of 50 mT and frequency of 100 kHz, the considerably low core loss of 67 kW/m3 was obtained. The low core loss and moderately high permeability of Fe–Si–B–Cr–C amorphous powder core across a wide frequency range indicate its potential for application in high frequency electronic components.
      PubDate: Wed, 07 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000771
      Issue No: Vol. 14, No. 2 (2024)
       
  • Bit-island arrangement and signal processing in double-layer magnetic
           recording technology

    • First page: 025114
      Abstract: The escalating demand for high-density storage of hard disk drives has prompted the innovation of advanced technologies to significantly boost an areal density (AD). Among these, three-dimensional magnetic recording systems incorporating double recording layers and bit-patterned magnetic recording (BPMR) have currently emerged as one promising solution. Therefore, this article investigates the integration of double-layer magnetic recording and BPMR technologies which is called double-layer BPMR, aiming for a substantial increase in AD. The primary focus lies on minimizing inter-layer interference and mitigating two-dimensional interferences by optimizing bit-island sizes for both upper and lower layers under the incorporation of staggered-like recording media arrangement and an array of magneto-resistive readers. Moreover, we also employ a rate-5/6 modulation code for compensating these effects. Detailed examinations reveal that our proposed system has a superior bit-error rate performance compared with conventional single-layer BPMR system.
      PubDate: Wed, 07 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000774
      Issue No: Vol. 14, No. 2 (2024)
       
  • Electromagnetic induction with time-varying magductance under constant
           magnetic field

    • First page: 025115
      Abstract: Electrical energy is becoming more popular due to the fact that it is economic, practical, clean, and easy to control and convert energy compared to other forms of energy. Currently, however, most of the electrical energy is converted from or to mechanical energy based on the well-known Faraday’s law of electromagnetic induction, which states that a current will be induced in a closed conductive coil exposed to a changing magnetic field. For that purpose, either the magnetic field itself must be changing or the magnetic field must be moving relative to the closed conductive coil. While investigating the physical significance of magductance (or magnetic-inductance), we unearthed a new electromagnetic induction mechanism that the electrical current is induced in a closed conductive coil with the invariant magnetic field by changing the magnetic parameter of magductance of the closed coil. Time-varying magductance is achieved by changing the conductivity of the coil. To demonstrate the feasibility of the electromagnetic induction, both theoretical validation and experimental verification are undertaken. We built a closed superconducting coil and successfully measured the induced electrical currents in the cooling process of the closed superconducting coil under an invariant magnetic field, thus verifying the new law of electromagnetic induction.
      PubDate: Thu, 08 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0185920
      Issue No: Vol. 14, No. 2 (2024)
       
  • A reconfigurable bipolar coil for wireless charging systems with
           interoperability and misalignment tolerance characteristics

    • First page: 025116
      Abstract: Wireless Power Transfer (WPT) technology has been developing rapidly in recent years. Electric Vehicles (EVs), as an emerging mode of transport, also benefit from the WPT technology. Various EV manufacturers have different coupling structures, which can lead to incompatibility problems between the coils. Meanwhile, due to the human parking, misalignment between the transmitting and receiving coils may occur. To solve these problems, this paper proposes a reconfigurable bipolar coil structure with both interoperability and misalignment tolerance. A 200-W experimental prototype is built, which can achieve 84.33% and 84.76% system transmission efficiency with vertical and horizontal bipolar coils. The effectiveness of the proposed reconfigurable bipolar coil is finally verified by comparing the computational and experimental results.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000674
      Issue No: Vol. 14, No. 2 (2024)
       
  • Maximizing the output power of magnetically geared generator in low-speed
           applications using subdomain modeling and particle swarm optimization

    • First page: 025117
      Abstract: This study presents an approach to optimizing the output power in a magnetically geared generator by employing subdomain modeling and particle swarm optimization. Accordingly, the subdomain analytical method is utilized to obtain the induced voltage, inductance which are used to predict output power. Afterward, the swarm intelligence optimization technique is applied to reach the maximum output power point. The 12/17/15 prototype evaluated the proposed model by comparing the calculated results and finite element method simulation.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000690
      Issue No: Vol. 14, No. 2 (2024)
       
  • Integrated approaches for road extraction and de-noising in satellite
           imagery using probability neural networks

    • First page: 025118
      Abstract: Remote sensing plays a crucial role in detecting and monitoring natural resources, extending its applications to various fields, such as geography, topographical surveying, and geoscience disciplines, including land management, forest monitoring, crop identification, soil mapping, and ocean resource finding. Road extraction holds significant importance among these applications, contributing to the development of Geographic Information Systems (GIS). The automatic updating of GIS information has become essential in daily life. Road extraction stands out as a prominent application within remote sensing image systems, addressing challenges related to intensity and width. Intensity challenges involve variations in spectral or color values of roads, while width challenges pertain to the issues associated with the size and structure of roads during the extraction process. Addressing the challenges associated with road extraction from remote sensing imagery is crucial for achieving accurate and efficient results. This paper under consideration compares the conventional and contemporary methods of road extraction, emphasizing completeness and correctness metrics. Conventional methods involve techniques like CLAHistogramEqualization for enhancement and fuzzy c-mean clustering for extraction, resulting in incremental improvements. To enhance results further, images are de-noised using Gray World Optimization and iterative domain-guided image filtering. To improve efficiency in road extraction, the authors proposed a contemporary approach through probability neural networks with de-noised images. The comparison is made based on the completeness and correctness of both conventional and contemporary methods.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0188523
      Issue No: Vol. 14, No. 2 (2024)
       
  • Experimental study and numerical analysis on the axial compression
           performance of CFRP strip reinforced round-end aluminum alloy tube
           concrete column

    • First page: 025119
      Abstract: Round-end aluminum alloy tube concrete columns had good durability and were very economical, but the low strength and elastic modulus of aluminum alloy led to the need for improvement in performance. This paper proposes carbon fiber reinforced plastic (CFRP) strip reinforced round-end aluminum alloy tube concrete (CREAC) columns and investigates their mechanical properties under axial compression loads. A total of eight specimens were tested, including seven CFRP reinforced specimens and one control specimen. The effects of the width, spacing, and number of layers of CFRP strips on the axial compression performance of CREAC under the same amount of CFRP were studied. The experimental results indicate that the main failure modes of the specimen are the buckling of round-end aluminum alloy tubes and the fracture of CFRP strips. The CFRP strip can significantly improve the ultimate bearing capacity of the specimen, with a maximum increase of 15.3% in the test range. When the amount of CFRP is the same, as the number of CFRP strips decreases, the bearing capacity and ductility deteriorate. Increasing the width and thickness of CFRP strips significantly improves ductility. On the basis of the validated finite element model, parameter analysis was conducted, and the calculation method for stability coefficients was fitted. A calculation method for axial compression bearing capacity suitable for CREAC was proposed, with a maximum error of less than 1% between the predicted results and experimental results.
      PubDate: Mon, 12 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0192324
      Issue No: Vol. 14, No. 2 (2024)
       
  • Comparison and research on load characteristics of PM in different
           permanent magnet synchronous machines

    • First page: 025120
      Abstract: PM enable PMSMs to have higher torque-density and power-density, however the machine performance is closely related to its load characteristics. When the armature excitation does not match the load characteristics of the PM and machine, it can lead to demagnetization and performance degradation. By comparing and studying the IPMSM’s and SPMSM’s load characteristics, a more reasonable machine topology of components such as PM can be obtained, and high-performance machines can be designed more efficiently. Based on the material characteristics of the PM, the armature reaction law of different machines and the demagnetization law of the PM at different current angles were analyzed. There are different magnetic field distribution patterns in IPMSM and SPMSM, and their different load characteristics are compared to study the methods for improving the anti-demagnetization ability of PMs based on different machine structures.
      PubDate: Tue, 13 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000805
      Issue No: Vol. 14, No. 2 (2024)
       
  • Effect of junction temperature on 1.3 µ m InAs/GaAs quantum dot lasers
           directly grown on silicon

    • First page: 025121
      Abstract: Laser junction temperature (Tj) is an essential parameter that directly affects the light power and lifetime of semiconductor lasers. Here, we investigate the effect of Tj on an InAs/GaAs quantum dot (QD) laser grown on a Si(001) substrate. Under 1% low pulsed current (1 µs pulse width and 100 µs period), the pure temperature-induced mode shift rate is 0.084 nm/°C. By increasing the duty cycle and measuring the corresponding mode wavelength shift, the laser’s Tj under the continuous-wave (Tj-CW) mode is predicted to be from 31.1 to 81.6 °C when the injection current increases from 100 to 550 mA. Next, the average thermal resistance is 36.2 °C/W. Moreover, the non-negligible increase in Tj-CW is analyzed to significantly reduce the mean-time-to-failure of Si-based QD laser, especially for cases under high CW injection currents. These results provide an accurate reference for the thermal analysis of silicon-based QD lasers and point the way to high performance on-chip light sources by improving the laser heat accumulation.
      PubDate: Tue, 13 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0168625
      Issue No: Vol. 14, No. 2 (2024)
       
  • Effect of nonthermal electron distributions on dust acoustic solitons in
           cometary plasmas

    • First page: 025122
      Abstract: We investigate the effect of nonthermal electrons modeled by two non-Maxwellian distribution functions, i.e., the (r, q) and Cairn’s distributions on the formation of dust acoustic (DA) solitons in an un-magnetized dusty plasma by incorporating the effect of dust streaming. We adopt the pseudopotential technique to obtain solitary wave solutions from fluid equations. It is seen that only rarefactive soliton can be obtained in such plasmas where ions are considered Boltzmannian and electrons non-Maxwellian. We find that soliton characteristics are strongly dependent on the nonthermal spectral indices r, q, and α and dust temperature Td. For (r, q) distribution, it is found that soliton amplitude increases but width decreases when the positive (negative) value of r decreases (increases). For Cairn’s distribution, we find that with the increase in α, soliton amplitude decreases. In space environments, such as cometary tails, solar wind, and Earth’s magnetosphere, where non-Maxwellian populations of electrons are present, our theoretical results show that the amplitude of soliton remains smaller than the Maxwellian case. Thus, Maxwellian distribution overestimates the soliton amplitude in such space environments. Therefore, we feel that our results will better interpret the results of observations, from cometary tails, and other space plasmas where nonlinear DA structures are likely to be observed.
      PubDate: Tue, 13 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0177023
      Issue No: Vol. 14, No. 2 (2024)
       
  • Back-contact perovskite light-emitting diodes

    • First page: 025123
      Abstract: Light-emitting diodes utilizing halide perovskites have experienced rapid advancements in recent years, demonstrating notable external quantum efficiencies. Despite these strides, the practical implementation of such devices remains constrained. In this contribution, we are dedicated to developing perovskite light-emitting diodes with a back-contact architecture using the MAPbBr3 active layer and SnO2 and Ni/NiOx back electrodes. The quantum efficiency of the fabricated devices stands at 0.015%. The operational voltage of the light-emitting diodes is characterized by its pronounced low values, attaining a maximum luminance of 70 cd/m2 at a mere 3.2 V. These results demonstrate the considerable promise of the developed back-contact perovskite light-emitting diodes for prospective applications in advanced display technologies and light communication systems.
      PubDate: Wed, 14 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189309
      Issue No: Vol. 14, No. 2 (2024)
       
  • Estimation method for bit upset ratio of NAND flash memory induced by
           heavy ion irradiation

    • First page: 025124
      Abstract: In order to estimate the bit upset ratio of NAND flash memory induced by heavy ion irradiation, starting from the physical mechanism of the bit upset of NAND flash memory, an analytical model based on statistical methods was developed to describe the relationship between heavy ion energy deposition near the floating gate, the threshold dose distribution of the memory array, and the bit upset ratio. The heavy ion irradiation experiment on NAND flash memory was conducted to verify the effectiveness of the estimation method. The maximum deviation between the fitting result of the analytical model and the experimental result is 5.0%, and the root mean squared error is 1.2 × 10−11. The analytical model can reflect the inflection point in the single event upset cross-section, which, according to the analytical model, is caused by the different proportions of the contribution of large events and small events defined in the model to the bit upset ratio. The analytical model also reflects the characteristics of the multiple-cell upsets from the side and is consistent with experimental results.
      PubDate: Wed, 14 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0188085
      Issue No: Vol. 14, No. 2 (2024)
       
  • A secure SoC architecture design with dual DMA controllers

    • First page: 025125
      Abstract: With the continuous advancement of System-on-Chip (SoC) technologies, the burgeoning data volumes emphasize the paramount importance of safeguarding data security and integrity. In this study, by leveraging Ascon in conjunction with enhancements to the SHA-1 algorithm, two secure Direct Memory Access (DMA) controllers are designed to facilitate data encryption and comparison, respectively, culminating in the proposal of an SoC architecture featuring dual DMA controllers. Simulation outcomes demonstrate the system’s ability to achieve a maximum clock frequency of 120 MHz, offering a throughput rate of up to 3.2 GB/s. The multi-master multi-slave AHB bus matrix within the system operates impeccably, ensuring smooth functionality. Furthermore, the two DMA controllers exhibit independent operation, featuring flexible start-stop capabilities. Notably, they operate harmoniously without conflicts, optimizing the area utilization while adhering to a low power consumption design methodology. The results unequivocally affirm the feasibility of designing a secure SoC integrated with two DMA controllers. This hardware-based approach effectively ensures data security, showcasing promising prospects for real-world applications.
      PubDate: Wed, 14 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0195148
      Issue No: Vol. 14, No. 2 (2024)
       
  • Revisiting the universality law in magnetically detected residual stresses
           in steels

    • First page: 025126
      Abstract: The dependence of residual stresses on differential permeability, determining the so called Magnetic Stress Calibration (MASC) curve, results in the Universal MASC curve after normalizing the stress and permeability axes with the yield stress and the maximum differential permeability of the steel under test, respectively. The motivation of this paper is to illustrate the ability of obtaining the MASC curve of an unknown steel just by measuring its yield stress and maximum differential permeability. The calculated MASC curve of an unknown type of steel, obtained by multiplying the stress and permeability axes of the Universal MASC curve with the yield stress and maximum differential permeability obtained by the stress-strain curve under simultaneous measurement of the permeability, was compared with the actual MASC curve of the same unknown type of steel determined by the classical method, with an agreement better than ±5%. The conclusion is that the actual MASC curve of an unknown type of steel can be determined just by a stress-strain measurement, with simultaneous determination of the maximum amplitude of the differential permeability.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000766
      Issue No: Vol. 14, No. 2 (2024)
       
  • Numerical analysis of horizontal bearing capacity of pile in clay slope

    • First page: 025127
      Abstract: In this study, a series of numerical calculations were performed to investigate the lateral behavior of piles in slopes and in horizontal ground. First, a numerical model is created and then verified by comparing the numerical results with the results of model tests. The numerical results agree well with the results of model tests. Second, numerical calculations of different slopes were conducted to explore the effect of slope angle on the horizontal displacement of pile and bending moment. Then, the effect of slope angle on the foundation stiffness proportional coefficient m is investigated. The stress distribution of soil around the pile and the deformation of pile at different slope angles are also compared. Finally, the p–y curves of the different slope angles are compared. An improved p–y method is proposed to consider the effect of slope angle based on the numerical results. The results show that the bearing capacity of piles decreases with an increase in slope angle. The horizontal displacement of pile nonlinearly decreases along the pile body with the depth of pile. The bending moment of piles increases along the pile body with an increase in pile depth, and until 0.5 times of the pile length, the bending moment reaches the maximum value. As the slope angle increases, the maximum of bending moment tends to decrease. The distance from the slope toe to the pile section has a little influence on the pile bending moment and horizontal displacement. With an increase in slope angle, the horizontal foundation coefficient m gradually decreases.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189318
      Issue No: Vol. 14, No. 2 (2024)
       
  • Results on partial approximate controllability of fractional control
           systems in Hilbert spaces with conformable derivatives

    • First page: 025128
      Abstract: This paper investigates partial approximate controllability of fractional linear and semi-linear control systems involving the conformable derivative. First, we derive sufficient and necessary conditions for partial approximate controllability of fractional linear systems over a small interval. Then, we apply a new approach, different from typical methods involving complexity inequalities and fixed point theorems, to obtain sufficient conditions for partial approximate controllability of semi-linear fractional control systems, assuming that the linear part is partially approximately controllable. The effectiveness of these results is demonstrated through an illustrative example.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0190334
      Issue No: Vol. 14, No. 2 (2024)
       
  • Research on the electro-magnetic protection technique of SCB bridge based
           on vertical punch through PN junction

    • First page: 025129
      Abstract: Pyrotechnic device is the key initiating component of weapon system, and its function reliability will directly affect the triggering of detonation and actuation mechanism. In order to enhance the survival ability of pyrotechnic device in intricate electromagnetic interference environment, it is necessary to carry out in-depth research on the electromagnetic protection technique of pyrotechnic device. In this paper, a new electromagnetic protection circuit based on vertical punch through PN junction device is proposed, which monolithically integrates the circuit with polysilicon semiconductor bridge on a single chip. The Electro-static Discharge (ESD) test was carried out according to the method specified by standard electrostatic standard 500 pF/500 Ω/25 kV, and the ESD capability of the proposed new chip was not less than 25 kV. Compared with the electromagnetic protection circuit by transient voltage suppressor diode based on lateral punch through junction device structure, the new chip increases the effective junction area of PN junction, reduces the current density, and increases the current conduction ability and electrostatic roughness of the diode. The new chip has a larger diode effective junction capacitance, which not only improves the ESD capability but also improves the RF protection capability at the same time.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0191824
      Issue No: Vol. 14, No. 2 (2024)
       
  • SHE-MTJ based ReLU-max pooling functions for on-chip training of
           neural networks

    • First page: 025130
      Abstract: We present a detailed investigation of various routes to optimize the power consumption of the spintronic-based devices for implementing rectified linear activation (ReLU) and max-pooling functions. We examine the influence of various spin Hall effect layers, and their input resistances on the power consumption of the ReLU-max pooling functions, we also access the impact of the thermal stability factor of the free-ferromagnet layer on the power consumption and accuracy of the device. The design for ReLU-max pooling relies on the continuous rotation of magnetization, which is accomplished by applying orthogonal spin current to the free-FM layer. We also demonstrate the non-trivial power-resistance relation, where the power consumption decreases with an increase in SHE resistance. We utilize the hybrid spintronic-CMOS simulation platform that combines Keldysh non-equilibrium Green’s function (NEGF) with Landau-Lifshitz-Gilbert-Slonzewski (LLGS) equations and the HSPICE circuit simulator to evaluate our network. Our design takes 0.343 μW of power for ReLU emulation and 17.86 μW of power for ReLU-max pooling network implementation at a thermal stability factor of 4.58, all while maintaining reliable results. We validate the efficiency of our design by implementing a convolutional neural network that classifies the handwritten-MNIST and fashion-MNIST datasets. This implementation illustrates that the classification accuracies achieved are on par with those attained using the ideal software ReLU-max pooling functions, with an energy consumption of 167.31 pJ per sample.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000685
      Issue No: Vol. 14, No. 2 (2024)
       
  • Fault feature extraction and diagnosis method for gearbox under variable
           operating conditions

    • First page: 025131
      Abstract: In this paper, a fault feature extraction method based on the combination of computational order tracking (COT) and variational mode decomposition (VMD) is proposed to solve the problem of fault feature extraction in a gearbox under variable speed conditions. First, a speed estimation method based on a forward-backward greedy algorithm and Fourier fitting is proposed to solve the speed estimation problem under variable speed conditions. Then, a feature extraction method based on COT, VMD, and fast kurtometry is proposed. COT is used to calculate the order. After the signal is decomposed by VMD, a fast kurtogram is used to filter the modal components with obvious fault features so as to extract fault features. Finally, combined with the analysis of actual equipment examples, the experimental results show that steady-state filtering can effectively filter the background noise and improve the signal-to-noise ratio. The rotation speed estimated by the forward–backward greedy algorithm and Fourier fitting is very close to the actual speed, which verifies that the method proposed in this paper can effectively solve the problem of fault feature extraction of a gearbox under variable speed conditions.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0181188
      Issue No: Vol. 14, No. 2 (2024)
       
  • Fully micromagnetic analysis of voltage-controlled magnetization switching
           in magnetic-topological-insulator-based devices

    • First page: 025132
      Abstract: We numerically investigate magnetization switching behavior in voltage-controlled magnetic-topological-insulator-based (VC-MTI) devices by means of the fully micromagnetic simulation. First, the influence of domain in VC-MTI devices was investigated. When the device size is larger than 1 µm, multidomain structure might appear. However, these domains disappear when the gate voltage and source-drain electric field are applied, which is the refresh operation of the actual VC-MTI device. The switching behaviors of a 100-nm-size VC-MTI device in the fully micromagnetic simulation are in agreement with those of the macrospin model although the gate pulse width is slightly different from that of the macrospin model. When the device is less than 1 µm, the macrospin model is adequate for the investigation of switching behavior in VC-MTI devices and the magnetization switching occurs in rotation mode. Therefore, for the VC-MTI device with less-than-100 nm size, the macrospin model is a good approach for the analysis of device operation and write-error rate.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000798
      Issue No: Vol. 14, No. 2 (2024)
       
  • DABCO-PEG ionic liquid catalyzed synthesis, single-crystal structure, and
           antioxidant activity of a flavanone derivative

    • First page: 025133
      Abstract: Globally, the occurrence of skin cancers has been increasing day by day due to unprotected skin and exposure to UV radiation. This research is focused toward the evaluation of the antioxidant potential of an OH-free flavanone derivative that was synthesized by using 1,4-diazabicyclo[2.2.2]octane–polyethylene glycol (DABCO-PEG) 400. Ionic liquid was prepared via the alkylation of DABCO using 1-pentyl bromide followed by mixing with PEG 400. The structure of the synthesized molecules was characterized through single-crystal XRD. The target flavanone, viz., 2-(4-isobutylphenyl)chroman-4-one, was subjected to free radical activity. In addition, in silico studies were carried out with proteins ribonucleotide reductase and tyrosinase and isobutyl containing flavanone, viz., 2-(4-isobutylphenyl)chroman-4-one. The flavanone 2-(4-isobutylphenyl)chroman-4-one showed significant inhibition at a concentration of 25 μg/ml compared to vitamin C, which was also supported by the molecular docking studies. The flavanones exhibit binding energies of −6.45 and −6.83 kcal/mol for ribonucleotide reductase and tyrosinase, respectively. The results were further validated by molecular dynamic simulations, which recommended that further investigation of this flavanone must be carried out before using it in potent drug discovery in the field of skin cancer.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0176219
      Issue No: Vol. 14, No. 2 (2024)
       
  • Study on the pyrolysis characteristics of styrene-grafted polypropylene
           cable insulation material

    • First page: 025134
      Abstract: Polypropylene (PP) has garnered significant attention as a cable insulation material due to its exceptional electrical performance and recyclability. Styrene-grafted polypropylene (PP-g) emerges as a promising alternative in this context. This study employs thermogravimetric-gas chromatography experiments and reactive molecular dynamics simulations to compare the pyrolysis process and decomposition products of pure PP and PP-g as cable insulation materials. Results indicate that while both materials produce similar pyrolysis products, PP-g exhibits greater resistance to decomposition than PP. The predominant hydrocarbons in the decomposition products include methane (CH4), ethylene (C2H4), propylene (C3H6), and ethane (C2H6). The relative proportion of hydrocarbons decreases with increasing temperature, with a shift toward increased C2H6 production. The ratio of C2H6 to (CH4 + C2H4) molecular weights in thermal decomposition products rises with temperature, suggesting enhanced stability. Graft modification alters the decomposition pathway, specifically increasing the generation of C2H6. This study lays a theoretical foundation for cable aging monitoring and life assessment.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189444
      Issue No: Vol. 14, No. 2 (2024)
       
  • Numerical analysis of discharge gap related fluctuations in a cylindrical
           positive discharge corona

    • First page: 025135
      Abstract: An efficient technique was used to model corona discharges without incorporating flux corrections. A position-state separation (POSS) technique was employed to solve the convection-dominated continuity equations prevalent in designing efficient corona discharges. The suggested approach utilizes an Eulerian scheme to solve the convective acceleration, diffusion, and response subproblems. The exceptional performance of POSS in terms of computing cost, resilience, and resolution is demonstrated by a series of numerical tests in various dimensions and coordinate systems. MATLAB was used to run four tests, namely, the square test, Davies test, general advection-diffusion test, and corona test. The average error in POSS was calculated as 0.06, which is much lower than the error in FEM-FCT (0.2677) and FVM-MUSCL (0.2650) algorithms. A 1 mm thick peak of space charge was formed around the anode after 1.2 ns. For an outer radius of 2 cm, ripples in ionizing waves were seen at t = 5000 ns. All the ionizing peaks were produced at around 0.5 cm away from the anode.
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0193785
      Issue No: Vol. 14, No. 2 (2024)
       
  • Impact of external magnetic field on temperature anisotropy driven Weibel
           instability in a magnetized plasma

    • First page: 025136
      Abstract: In this paper, we investigate the impact of an external magnetic field on the Weibel instability driven by temperature anisotropy in a magnetized plasma. The study provides the influence of electron temperature anisotropy, considering both cold as well as warm ions. We derive expressions for the growth rate Γ (s−1) in each case to quantify the effect of some specific parameters on the instability. For example, the growth rate is plotted against the magnetic field for three distinct cases: considering only electrons, including cold ions, and incorporating warm ions. It is observed that the growth rate decreases as the applied magnetic field increases. Furthermore, the addition of both cold and warm ions to the plasma significantly influences the observed effects. It can be explained as follows: in the presence of cold ions, the growth rate is decreased with an increase in the wave number kz (cm−1). In addition, a decrease in the growth rate is observed with an increasing wave number in the case of warm ions. Therefore, it can be seen that the Weibel instability, propelled by thermal anisotropy, holds significant implications owing to its prevalence in both astrophysical and laboratory plasmas. The findings presented here are expected to contribute to the advancements in magnetic field generation and particle acceleration in various astrophysical phenomena, including gamma-ray bursts, relativistic collisionless shock fronts, radio supernovae, and pulsar winds.
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189656
      Issue No: Vol. 14, No. 2 (2024)
       
  • Polyethylene glycol-stabilized cationic liposome encapsulating glucosamine
           sulfate: A promising nanoformulation for osteoarthritis therapy

    • First page: 025137
      Abstract: Osteoarthritis (OA) is a common orthopedic chronic disease, and the use of nanomaterials as carriers is an effective way to realize slow and controlled release therapy for OA drugs. In this study, we synthesized a polyethylene glycol-stabilized bilayer-decorated cationic liposome (CLis) as a drug delivery system for delivering glucosamine sulfate (GS) drug to achieve the treatment of OA in rats. The CLis encapsulated with GS drug (GS-CLis) was prepared by a reverse evaporation method, and its physical properties, encapsulation rate, and drug release performance were evaluated. The biological properties of GS-CLis were evaluated in vitro. The therapeutic effect of GS-CLis on osteoarthritis was evaluated in vivo, and the in vivo biosafety of the drug was assessed by hematology, blood biochemistry, and hematoxylin-eosin staining. GS-CLis had a particle size of (236.28 ± 4.76) nm, a potential of (27.35 ± 4.86) mv, and a spherical shape. The encapsulation rate was (96.18 ± 5.77)% and the drug-loading capacity was (9.61 ± 0.28)%, which provided a good slow drug release. GS-CLis has low cytotoxicity, low hemolysis rate, and good biocompatibility. GS-CLis can more effectively alleviate joint surface damage and inhibit the expression of inflammatory factors, and has no significant effect on the body weight of rats, with good biological safety. In this study, we successfully synthesized novel GS-CLis for the treatment of OA, which improved the retention time and therapeutic effect of GS in OA and provided a research basis for its development as an OA nanoformulation.
      PubDate: Wed, 21 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189591
      Issue No: Vol. 14, No. 2 (2024)
       
  • Enhancement of photon–magnon coupling strength by inverted
           split-ring resonator at GHz

    • First page: 025138
      Abstract: A series of inverse split-ring resonators (ISRR) loaded with an yttrium iron garnet (YIG) film were numerically and experimentally studied to provide strong photon–magnon coupling strength and cooperativity enhancement. An increase in the photon–magnon coupling strength and cooperativity has been achieved due to the simultaneous increase in the spatial overlapping between the ISRR microwave electromagnetic field magnetic component and the uniform magnon mode in the YIG, and the appearance of spatial areas with higher ISRR electromagnetic field magnetic component strength. Practically, this was reached for the ISRR by increasing the conducting gap length and changing the conducting gap shape by protrusions forming. Higher values of spin-number-normalized photon–magnon coupling strength gN and cooperativity C were reached in all cases for the ISRR with protrusion (compared with ISSR with identical conducting gap length but without protrusion). All resonators presented in this paper seem to be more prospective for the realization in quantum hybrid systems than conventional split-ring resonators and ISRR.
      PubDate: Wed, 21 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0187796
      Issue No: Vol. 14, No. 2 (2024)
       
  • Exploring association of aerosols based on meteorological factors over
           mega city Lahore (Pakistan) and central place of Indo-Gangetic basin

    • First page: 025139
      Abstract: Urban air pollution poses a significant challenge, negatively affecting visibility, agriculture, health, and transportation. This research focused on exploring the variability of aerosols using the autoregressive distributed lag (ARDL) approach. To achieve this, monthly aerosol data were obtained from the Aura satellite’s Ozone Monitoring Instrument (OMI) at a distance of 500 nautical miles. In addition, meteorological factors such as Cloud Fraction (CF), Relative Humidity (RH), Tropopause Height (TH), Total Column Water Vapor (TCWV), Water Vapor Mass Mixing Ratio (WVMMR), Surface Skin Temperature (SST), Surface Air Temperature (SAT), and Geopotential Height (GH) were gathered from the atmospheric infrared sounder (AIRS) onboard the AQUA satellite. The MERRA-2 model provided the Total Surface Precipitation (TSP) and Surface Wind Speed (SWS). To assess the short- and long-term relationship between aerosols and meteorological parameters, the ARDL bounds testing technique was applied. The study found evidence of a long-term relationship and co-integration between the variables of interest and aerosols when aerosols were the dependent variable. Particularly, GH, SST, and SWS exhibited both long-term and short-term impacts on aerosol variability. SWS, in particular, was found to have a significant influence on aerosol variability. Conversely, CF, TSP, and WVMMR were found to have no significant impact on aerosol variability. To ensure the stability of the model, the CUSUM test was employed, confirming its stability. Furthermore, the prediction model demonstrated a good fit, bolstering the reliability of our findings.
      PubDate: Thu, 22 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0187075
      Issue No: Vol. 14, No. 2 (2024)
       
  • Smart nanocomposites: Harnessing magnetically recoverable MWCNT-CF for
           

    • First page: 025140
      Abstract: The accelerating use of organic dyes in various industries has led to a surge in water pollution, especially from non-biodegradable dye effluents discharged into water resources. This study addresses the critical issue of catalyzing the reduction of two prevalent dyes, methylene blue (MB) and rhodamine-B (RhB), using a multiwalled carbon nanotube-cobalt ferrite (MWCNT-CF) nanocomposite. The synthesized nanocomposite demonstrates exceptional catalytic activity, stability, and recyclability. Conventional methods for treating dye-containing wastewater often prove expensive. This study explores the efficacy of catalytic reduction, a relatively fast process facilitated by semiconductor nanoparticles. Structural analyses using X-ray diffraction and high-resolution transmission electron microscopy (HRTEM) confirm the formation of the nanocomposite, revealing unsaturated surface bonds and chains conducive to adsorption. The nanocomposite exhibits a remarkable reduction in both dyes, with easy recyclability for multiple cycles. Magnetization studies confirm the ferrimagnetic nature of the nanocomposite, facilitating its efficient separation from the reaction mixture using a magnet. The study delves into the kinetics of the catalytic reduction following pseudo-first-order kinetics. The surface modifications of the nanocomposite, as revealed by TEM, contribute to enhanced adsorption and catalytic efficiency. Notably, the MWCNT-CF nanocomposite demonstrates negligible loss of catalytic activity during recycling, highlighting its potential for cost-effective and sustainable applications in dye reduction across various industries.
      PubDate: Thu, 22 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0191631
      Issue No: Vol. 14, No. 2 (2024)
       
  • Modeling Fermi energy, free-carrier density, and resistivity in degenerate
           n-Ge

    • First page: 025141
      Abstract: A new expression for Fermi energy vs doping is derived using the standard model for free carriers in n-type semiconductors. The new expression is composed of the Fermi energy in non-degenerate semiconductors, a doping function for bandgap narrowing (BGN), and an adjustable energy variation. In non-degenerate semiconductors, the new expression is equivalent to the standard Boltzmann expression. Calculated curves of Fermi energy are assigned in the Fermi–Dirac expression for the donor ionization ratio, and reported data of electron density and resistivity measured in heavily doped n-Ge layers are fitted. Five reported doping functions for BGN are used. One of the BGN functions allows modeling frustrated incomplete ionization. Another allows modeling bandgap widening.
      PubDate: Thu, 22 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0163730
      Issue No: Vol. 14, No. 2 (2024)
       
  • MPQA method applied to the plasma dispersion function

    • First page: 025142
      Abstract: A new approximation method for the plasma dispersion function Z(ζ) is presented. Multipoint quasi-rational approximation technique is used to find a bridge function that connects the power series and the asymptotic expansion of the function Z(ζ) using rational functions combined with exponential functions. An approximation with a polynomial of degree 10 is performed for the function Z(ζ), and the results obtained are compared with those of previous approximations from the literature. The results of this approximation were a relative error of ɛ = 0.0035 for Re[Z̃(ζ)] and a relative error of ɛ = 0.0011 for Im[Z̃(ζ)], which are lower than those of the other existing approximations.
      PubDate: Mon, 26 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0184424
      Issue No: Vol. 14, No. 2 (2024)
       
  • Shape optimization using the adjoint solver in computational fluid
           dynamics for additive manufacturing of a pollen filter

    • First page: 025143
      Abstract: Pollen filters play an essential role in protecting people from airborne allergens and ensuring indoor air quality. Allergic reactions to pollen can lead to discomfort, reduced productivity, and increased healthcare costs. A low pressure drop of these pollen filters not only enhances the comfort of individuals using the filters but also contributes to energy savings in ventilation systems, thereby promoting environmental sustainability. This research focuses on the shape optimization of pollen filters using the adjoint solver in computational fluid dynamics, aiming to enhance both human health and environmental sustainability. In a previous study, an approach using the adjoint solver was developed to optimize both the separation efficiency and the pressure drop. In the current work, a methodology is presented that exploits these findings and allows the design of initial structures, subsequent optimization, and detailed experimental and numerical comparisons with a reference filter using the example of a pollen filter. To validate the effectiveness of the optimized filter, the initial geometry and the optimized geometry were fabricated and tested on a test bench. Compared to a reference filter, our filter disk was able to separate 2.9% more particles of size 6 μm and the pressure drop was lower by 34.2%. This research work demonstrates that the developed method can effectively be used to improve the performance of pollen filters. The results obtained from the validation suggest that the optimized geometry of the filter exhibits higher separation efficiency while keeping the pressure drop low compared to state-of-the-art pollen filters.
      PubDate: Mon, 26 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0190320
      Issue No: Vol. 14, No. 2 (2024)
       
  • Design and theoretical study of new configuration of photovoltaic/thermal
           (PVT) solar collector

    • First page: 025144
      Abstract: This study aims to compare how well different designs of combined photovoltaic-thermal collectors work in terms of electricity and heat production. One big benefit of photovoltaic-thermal collectors, compared to regular solar panels, is that they cool down the module and make it produce more electricity efficiently. In simple terms, using this method produces heat and electricity in a device, which means one needs less space to install the collector and module. In a recent study, scientists looked at how well different designs of a solar panel that is also used to generate heat performed. They tested using water to keep it cool. To study and understand how different shapes and sizes affect the performance of a solar panel, we used a computer program called MATLAB to create models of the panel. The research shows that the sheet and tube design with a round or rectangular shape is the most efficient in terms of heat and overall performance. Moreover, when a glass cover is present, it causes electricity to be less efficient while making heat efficiency and overall heat energy higher.
      PubDate: Tue, 27 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0187916
      Issue No: Vol. 14, No. 2 (2024)
       
  • Optimization of OpenCV based spot identification method for surface
           plasmon resonance imaging

    • First page: 025145
      Abstract: In this work, we focus on the OpenCV based microarray recognition method for Surface Plasmon Resonance Imaging (SPRi), proposing the hit-ratio of global light pixels and coverage of the potential spots in a microarray as the criteria for identification evaluation in SPRi data. We optimized the design of the ellipse fitting strategy by analyzing the impact of different parameters in the method. After optimization of the parameters, the accuracy of microarray recognition was successfully increased to over 90%. This work not only contributes to reducing errors in microarray signal extraction and improving signal processing quality but also has significant implications for applying computer graphic technology in high-throughput biochemical analysis.
      PubDate: Wed, 28 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0192315
      Issue No: Vol. 14, No. 2 (2024)
       
  • A novel motivation for the unstable nonlinear Schrödinger equation
           through random inputs

    • First page: 025146
      Abstract: We investigate the stochastic unstable nonlinear Schrödinger equation through bi-random sources. Specifically, we solve this equation via Itô sense, with the parameter following Laplace and Gumbel distributions. We provide vital stochastic solutions in applied sciences. We employ He’s semi-inverse technique in order to provide these solutions in a unified way. Actually, this is the first time that the same model has been taken into account in these circumstances. In order to investigate the real relevance of the stochastic unstable nonlinear Schrödinger equation, we provide the simulations for some of the collected solutions using the appropriate parameter settings provided by the MATLAB software. Finally, our renewed drive might expand to incorporate further emerging natural science models.
      PubDate: Wed, 28 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0196489
      Issue No: Vol. 14, No. 2 (2024)
       
  • The effect of powder shape on the magnetic anisotropy in NdFeB bonded
           magnets

    • First page: 025201
      Abstract: The advent of NdFeB bonded magnets with freedom of shape design is effective in achieving motor size and weight reductions. In this paper, the NdFeB bonded magnets were produced through calendaring molding, and the effect of powder shape on degree of alignment (DOA) of NdFeB bonded magnets was investigated. The magnetic measurement results demonstrate that platelet-shaped anisotropic Master Quality Authenticated (MQA) powders exhibit a significantly higher DOA compared to sphere-shaped anisotropic HDDR powders. Microstructural analysis reveals the presence of an oriented structure induced by mechanical stress in MQA bonded magnets, resulting in magnetic anisotropy. This observation is consistent with the difference in X-ray diffraction (XRD) patterns between the cross-section and surface of MQA bonded magnets. Conversely, spherical HDDR particles display minimal orientation and maintain a random distribution, resulting in magnetic isotropy. The XRD pattern of the cross-section of HDDR bonded magnets closely resembles that of its surface. In summary, our findings highlight the superior potential of platelet-shaped anisotropic MQA powders for achieving enhancing magnetic properties during the calendaring molding process, in contrast to sphere-shaped anisotropic HDDR powders. This study provides valuable insights into the determinants of mechanical particle orientation during the fabrication of anisotropic NdFeB bonded magnets, with implications for the development of high-performance bonded magnets.
      PubDate: Thu, 01 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000635
      Issue No: Vol. 14, No. 2 (2024)
       
  • Magnetic and magnetocaloric properties of rare earth intermetallic
           compound Gd 3 Co 4 Ge 13

    • First page: 025202
      Abstract: Magnetic and magnetocaloric properties of polycrystalline Gd3Co4Ge13 (Cubic, Yb3Rh4Sn13-type, Space group Pm-3n, No. 223, cP40) have been studied by carrying out dc magnetization measurements in applied magnetic fields up to 140 kOe. The compound Gd3Co4Ge13 orders antiferromagnetically at 9 K (TN). The antiferromagnetism appears to be weak and with increasing applied magnetic fields, ferromagnetic interactions become dominant. This field-induced antiferromagnetic to ferromagnetic state that is marked as a change from inverse to normal magnetocaloric effect in the isothermal magnetic entropy change vs temperature plot around TN. At 2 K, the magnetization shows a tendency toward saturation in applied magnetic field and a magnetic moment of 5.3 µB per Gd3+ is obtained in 140 kOe field.
      PubDate: Thu, 01 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000806
      Issue No: Vol. 14, No. 2 (2024)
       
  • Development of a high-efficiency and wide-irradiation coil for
           transcranial magnetic stimulation therapy at home

    • First page: 025203
      Abstract: To perform transcranial magnetic stimulation therapy at home, a stimulation coil that is robust against misalignment must be employed. A dome-shaped coil is one such coil; however, it has the disadvantage that the induced electric field is smaller than that of the conventional figure-8 coil. In this study, we developed a double D-shaped coil with a horizontal return path to suppress the influence of the return current, while reducing the inductance of the coil. After optimizing geometric parameters of the double D-shaped coil through numerical simulations, we fabricated the coil and evaluated its performance on healthy subjects. It was confirmed that the developed coil was found to tolerate a wider range of positioning errors than the figure-8 coil when stimulating the motor cortex.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000748
      Issue No: Vol. 14, No. 2 (2024)
       
  • Sintering temperature optimization for enhanced magnetic performance in
           La–Ca–Co doped strontium ferrite

    • First page: 025204
      Abstract: The effectiveness of employing La-Ca-Co co-doping has been demonstrated as the optimal approach for enhancing the magnetic performance of strontium ferrite. However, limited studies have explored the evolution of the magnetoplumbite phase and its correlation with the sintering temperature. In our research, La-Ca-Co doped strontium ferrite permanent magnets were fabricated using a conventional ceramic process and a two-step sintering technique. After sintering at different temperatures, all the samples possess proper c-axis orientation. When the sintering temperature was raised from 1175 °C to 1205 °C, there was an upward trend observed in the remanence Br, increasing from 430 mT to 439 mT. The coercivity Hcj exhibited an increase from 380 kA/m and reached its peak at 397 kA/m at 1185 °C. Although the Br value remained favorable, the coercivity experienced substantial deterioration, reaching its lowest point at 303 kA/m at 1205 °C. Under a sintering temperature of 1195 oC, magnetic performance with optimal energy product was achieved, with Br of 439 mT, Hcj of 379 kA/m, Hcb of 318 kA/m, and (BH)max of 35.5 kJm-3.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000653
      Issue No: Vol. 14, No. 2 (2024)
       
  • Magnetic nanoparticles (MNPs) based additively manufactured memory devices

    • First page: 025205
      Abstract: Magnetic nanoparticles (MNPs) in a suspension have been shown to change resistance by an order of magnitude based on an applied field. We have prepared the MNPs samples with matrices of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PDOT:PSS) or H2O, and Co MNPs and carried out the magnetoresistive measurements. A switch-based model is used to understand the mechanism for the change in resistance. We further propose devices for memory based on MNPs. Building blocks for these devices are then fabricated using additive manufacturing techniques and measurements of change in resistance under the influence of a magnetic field are conducted. Niche applications of additive manufacturing techniques to the fabrication of these devices are proposed. The device uses MNPs suspended in a soft matter matrix. The application of a magnetic field is used to move the MNPs to or away from electrical contacts. Depending on the change of position of the MNPs, a connection is either made or broken, which can act as a 1 or a 0. The measured change in resistance observed in such devices is more than an order of magnitude depending on the matrix solution. The proposed device and its manufacturing process could be feasible for magnetic memory and in-memory computing devices on any flexible substrates.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000758
      Issue No: Vol. 14, No. 2 (2024)
       
  • Investigation of the over-load unintentional remagnetization effect in
           series hybrid magnet variable flux memory machine

    • First page: 025206
      Abstract: Variable flux memory machines (VFMMs) have become a research hotspot due to their adjustable air-gap flux with the employment of low coercive force (LCF) permanent magnets (PMs). Series hybrid magnet VFMMs (SHM-VFMMs) utilizing series-magnetic-circuit high coercive force (HCF) and LCF PMs are extensively investigated due to their excellent unintentional demagnetization (UD) withstand capability. Nevertheless, the existing researches still focus on the UD of LCF PMs under heavy load operation, and the remagnetization issue remains unreported. Therefore, in this paper, the over-load unintentional remagnetization (UR) effect of the a dual-layer-SHM-VFMM (DLSHM-VFMM) is first revealed, and its mechanism is investigated and analyzed in depth based on finite element (FE) analyses. A DLSHM-VFMM prototype is manufactured and tested to verify the effectiveness of the theoretical analyses.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000744
      Issue No: Vol. 14, No. 2 (2024)
       
  • Magnetocaloric effect in aluminum doped ErCr 1−x Al x O 3
           orthochromites

    • First page: 025207
      Abstract: Aluminum-doped ErCr1-xAlxO3 orthochromites prepared via autocombustion technique were investigated for their magnetic and magnetocaloric properties. X-ray diffraction confirmed that samples were orthorhombic phases with the Pbnm space group without a trace of any impurity. As analyzed via Rietveld refinement of XRD data, structural parameters such as lattice parameters, volume, bond angle, and bond lengths were affected by doping nonmagnetic Al3+ in the compound. ErCrO3 possesses the long-range antiferromagnetic ordering with a weak display ferromagnetism at TN =133 K. Low-temperature high-field magnetic study shows a decrease in Neel temperature (TN ∼ 114 K for x = 0.5), suggesting magnetic ordering suppression due to Al3+ doping. The asymptotic paramagnetic Curie temperature Tcw = −25 K suggests the predominance of antiferromagnetic interactions in ErCrO3 orthochromites, which was observed to increase with Al3+ doping. Isothermal magnetization data show changes in magnetic entropy (−ΔSMmax) and relative cooling power (RCP). The magnetic entropy change, −ΔSMmax, for ErCrO3 estimated from magnetization measurements show 11.60 J kg−1 K−1 at 11 K and a relative cooling power (RCP) of 209.4 J kg−1 at 5 T applied field. While ErCr0.75Al0.25O3 show a maximum magnetic entropy of 11.52 J kg−1 K−1 at 11 K with a 5 T applied field and RCP of 186.66 J kg−1, whereas ErCr0.5Al0.5O3 displayed −ΔSMmax of 11.63 J kg−1 K−1 at 5 K with a 5 T applied field and RCP value of 160.78 J kg−1. The results show that nonmagnetic doping, such as Al3+, could maintain the compound’s magnetocaloric property to an extent.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000794
      Issue No: Vol. 14, No. 2 (2024)
       
  • Anomalies in the magnetostrictive modulation of love surface acoustic
           waves

    • First page: 025208
      Abstract: A magnetic surface acoustic wave (SAW) sensor is built by growing a 100 nm galfenol (Fe72Ga28) film by sputtering between the interdigitated transducers of a SAW delay line. Love waves are produced when the shear waves excited on the piezoelectric substrate are guided by a 3.1 μm layer of amorphous SiO2. Due to the magnetostrictive nature of galfenol deposited on top, the application of magnetic fields modulates the propagation of the mechanical excitations along the sensor by the strain coupling. By introducing the delay line in a feedback loop circuit, these changes are studied as resonant frequency variations. Magnetic field cycles of ±40 mT are applied to the sample and the resonant frequency shift is tracked simultaneously. The sensor exhibited hysteretic frequency behavior that depends on the orientation of the applied magnetic field relative to the direction of Love wave propagation. In the configuration in which the wave vector and the applied field form an angle of 45°, the resonant frequency seems to increase with the magnetization induced by the external field. When the wave vector propagation is parallel to the field, two positive peaks appear close to the coercive field of the film, which has not been reported before. This is probably due to a more complex relationship between the acoustic wave and the magnetic state of the film which could be exploited to give rise to new models of magnetic sensors.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000749
      Issue No: Vol. 14, No. 2 (2024)
       
  • Synthesis and characterization of novel iron-modified geopolymer cement
           from laterite clay as low energy material

    • First page: 025209
      Abstract: A new type of geopolymer with an iron–oxygen–silicon linkage is synthesized and reported for the first time. The aim was to enable the iron-rich clay material (laterite) as a raw material for the geopolymerization. Iron was used in different ratios ranging 1–3 wt. % in the raw mix designing geopolymer followed by activation with concentrated alkali solutions of NaOH and KOH in different concentrations. The bonding of Fe–O–Si was confirmed from the FTIR peaks in NaOH- and KOH-based geopolymers. X-ray diffraction studies confirmed the formation of zeolitic, sodalite, and almandite phases. The final product has shown a compressive strength of 2371.8 and 1503 kN/m2 and can be used as a construction material.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0177022
      Issue No: Vol. 14, No. 2 (2024)
       
  • Tunable broadband terahertz absorber based on graphene with bilayer
           hexagonal

    • First page: 025210
      Abstract: An ultra-wideband absorber with an absorption rate of near unit is studied and numerically simulated in the terahertz frequency band. The proposed absorber is a stacked compact structure consisting of a double-layer patterned graphene embedded between two separated dielectric. Under normal incidence, the absorption rate exceeds 99% at 2.31–3.92 THz. The absorption bandwidth can reach 2.54 THz for absorptions greater than 90% (1.91–4.45 THz), and the relative bandwidth achieves 80%. Furthermore, the absorber is tunable, with absorption ranging from 14% to almost 99.9% by altering the Fermi energy of graphene from 0 to 1 eV. The phenomenon of ultra-wideband absorption is analyzed in relation to impedance matching and field distribution. Moreover, the absorber has high polarization-independence and can operate across a broad range of incidence angles. This tunable ultra-wideband absorber has promising functions in modulation, stealth, switching, and imaging technologies.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0191024
      Issue No: Vol. 14, No. 2 (2024)
       
  • Impurity effect on magnetic and thermal properties of S = 3/2 spin gap
           system Ba 3 Ca(Ru 1−x Nb x ) 2 O 9

    • First page: 025211
      Abstract: We have investigated the nonmagnetic impurity effects on magnetic and thermal properties for the spin gap system Ba3CaRu2O9, which has the Ru2O9 dimers composed of two Ru5+ spins (S = 3/2). The measurements of the magnetic susceptibility and specific heat have been carried out for the polycrystalline samples of Ba3Ca(Ru1−xNbx)2O9, where the Ru5+ spins are partially substituted by the non-magnetic Nb5+ ions. We have observed the magnetic behavior of the remained Ru5+ spins derived from breaking the singlet formation by the Nb-doping. These magnetic behaviors can be understood by the S = 3/2 free spin model under an internal magnetic field. Based on the obtained results, the mechanism of the singlet formation of Ba3CaRu2O9 is discussed.
      PubDate: Tue, 06 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000667
      Issue No: Vol. 14, No. 2 (2024)
       
  • Wet chemistry-synthesized Fe/mixed ferrite soft magnetic composites for
           high-frequency power conversion

    • First page: 025212
      Abstract: State-of-the-art soft magnetic (SM) alloy systems such as electrical steels and permalloys exhibit large eddy current losses at high-frequency (kHz range and above), limiting their application in fast switching devices. Eddy current losses can be reduced for metallic alloys through a decrease in characteristic length scale or embedding them in an insulation layer. This work proposes the development of fine-scale core materials consisting of metallic SM nano/microparticles with magnetic, inorganic insulation layers, and their synthesis using a wet chemistry-based, scalable method for high frequency and high-power applications. More specifically, a magnetic ferrite coating (Ni0.5-xMnxZn0.5Fe2O4, x = 0.0–0.5) was applied via deposition of ferrite powder produced using a “wet chemistry-based” co-precipitation method; the ferrite was distributed through the Fe micropowder via either ball milling or ultrasonic mixing. Powder cores were prepared by compaction of the synthesized composites. Relative magnetic permeability and core loss were measured at excitation frequencies to 200 kHz. A core loss of 127 kW/m3 was measured at excitation frequency of 100 kHz and magnetization of 0.02 T. This value improves on the 199.3 kW/m3 reported in literature at identical excitation conditions for a compact formed from a composite comprising Fe microparticles coated with low-permeability Ni0.5Zn0.5Fe2O4. Ultrasonic mixing resulted in slightly lower core loss than ball milling, possibly because ball milling causes loss-increasing deformation of the Fe micropowder. XRD and SEM were used to observe composite composition and core cross-section microstructure.
      PubDate: Tue, 06 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000835
      Issue No: Vol. 14, No. 2 (2024)
       
  • PZT-based flexible piezoelectric sensors for real-time condition
           monitoring

    • First page: 025213
      Abstract: Endowed with high sensitivity, fast response, and excellent flexibility, flexible piezoelectric sensors proffer substantial advantages for establishing efficacious contact with coarse object surfaces. They exhibit remarkable potential for application in wearable devices, motion state recognition, and device vibration monitoring. This paper introduces the development of a novel pliable piezoelectric nanocomposite harnessing modified lead zirconate titanate (PZT) and a flexible photosensitive resin. The PZT-based flexible piezoelectric sensors were fabricated using the light-curing molding technique. By establishing a sensor test platform, the performance parameters of the PZT-based sensors were obtained. Compared to conventional flexible piezoelectric sensors, the output voltage of the PZT-based sensors increased by 1.67 times under the same excitation, resulting in an improved response time and sensitivity. Moreover, the sensors demonstrated an excellent voltage output performance for recognizing human motion states and monitoring electrical equipment vibrations, both in real-time motion state changes and in core vibration under high-frequency operating conditions. These 3D-printed flexible piezoelectric sensors assume paramount significance across diverse domains, including motion science and real-time equipment condition monitoring.
      PubDate: Tue, 06 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0167451
      Issue No: Vol. 14, No. 2 (2024)
       
  • Size dependence of domain wall mediated switching dynamics of
           perpendicular magnetic tunnel junctions in the presence of reference layer
           stray field

    • First page: 025214
      Abstract: Recent investigations on spin-transfer-torque-induced switching dynamics of perpendicular magnetic tunnel junctions (MTJ) have revealed different switching anomalies. Here, the influence of stray field from a synthetic anti-ferromagnet (SAF) based reference layer on the domain wall (DW) mediated switching of the free-layer magnet is studied via finite temperature micro-magnetic simulations for varying MTJ diameters. For larger diameters (∼80 – 120 nm), a stray field gives rise to persistent back-and-forth oscillation of the unswitched domain, delaying the switching process and causing increased write errors. For smaller diameters (∼30 – 56 nm), quasi-coherent switching occurs, as expected. For the intermediate ranges of MTJ diameters (∼60 – 70 nm), another switching mode emerges where a bubble-like feature is observed to evolve during the switching process, causing a very rapid change in magnetization. These paths are observed to originate from DWs partly in Bloch and partly in Néel configuration. We find that at the intermediate ranges of device size, the stray field becomes stronger for a given SAF configuration, and the energy difference between the Néel and Bloch configurations is also lowered. Hence, a stronger stray field could easily distort the DW propagation in the Walker breakdown regime, leading to such magnetization behavior. Our findings present interesting insights into DW-mediated switching modes in perpendicular MTJ structures caused by unoptimized stray fields from the SAF.
      PubDate: Wed, 07 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000822
      Issue No: Vol. 14, No. 2 (2024)
       
  • Magneto-optical characterization of TCO films using standard and enhanced
           configurations

    • First page: 025215
      Abstract: Thin film samples like transparent conducting oxides (TCO) are typically investigated using measurements like Hall Effect and 4-point probe measurements. We use a sensitive AC Faraday rotation (FR) setup to study thin film samples for which a magneto-optic response is challenging to characterize. The experimental setup employs a stabilized He-Ne laser (633 nm) along with an AC magnetic field that enables lock-in detection. We investigate a series of TCO samples that are deposited on a glass substrate. The TCO samples include the more widely used Indium Tin Oxide (ITO) and the relatively newer Fluorine doped Tin Oxide films, usually referred to as FTO. These films have a magneto-optic response due to the presence of free carrier concentration and therefore measurement of this response (Verdet constant) could allow one to determine the carrier concentration of these films. Given that magneto optic responses like FR depend on the length of the sample length traveled by light, these sub-micron films pose considerable challenges in trying to extract the FR response of the film from that of the much thicker glass substrate. Furthermore, we present details of the design and FR characterization of samples using a Michelson interferometer-based measurement setup which enhances the Faraday rotation and affords a new means of studying harmonic peaks of the recorded optical signal in response to a sinusoidally-varying applied magnetic field. We compare some early results from this setup to the typical “single-pass” setup to highlight the difference in the recorded signals from the two setups. To showcase the advantages of the proposed measurements, we also include some early results from a very different type of sample, namely superparamagnetic nanoparticles (SNPs).
      PubDate: Wed, 07 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000751
      Issue No: Vol. 14, No. 2 (2024)
       
  • Magnetic field-induced narrow first-order and metamagnetic phase
           transitions of Nd 5 Ge 3

    • First page: 025216
      Abstract: We report on the magnetic behaviour of Nd5Ge3 by investigating through magnetization, neutron diffraction and muon spin relaxation measurements. Temperature dependent-magnetization, muon depolarization rate (λ), initial asymmetry (A0) and the stretched exponent (β) show a clear anomaly at the Néel temperature TN ∼ 54 K. However, the short-range correlated ferromagnetic interactions below TN are inferred from the diffuse scattering mechanism as revealed by zero-field neutron diffraction data. Narrow first order phase transition is due to the competing interaction of a high temperature weak-antiferromagnetic and low temperature glassy states. Magnetic field-induced reentrant spin glass state from a magnetic glass state is observed, before it transforms to a ferromagnetic state.
      PubDate: Wed, 07 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000636
      Issue No: Vol. 14, No. 2 (2024)
       
  • Path planning of water surface garbage cleaning robot based on improved
           immune particle swarm algorithm

    • First page: 025217
      Abstract: In order to effectively improve the efficiency of surface garbage cleaning robot, an intelligent control algorithm was applied to plan the robot path. To do so, an improved immune particle swarm algorithm was developed based on the robot model. This algorithm introduced the adaptive information dynamic adjustment strategy to dynamically adjust the main link indices, which improved the global searchability and convergence of particles and facilitated the quick identification of the optimal path by the robot. Through comparative simulation experiments with the particle swarm optimization algorithm, genetic algorithm, and immune particle swarm optimization algorithm, it was found that the robot based on the Adaptive Immune Particle Swarm Optimization (AIPSO) algorithm had the shortest planning path and search time, the lowest energy consumption, and the highest efficiency. A robot prototype platform was built. Compared to other algorithms, the efficiency of the robot space search based on the AIPSO algorithm was the highest, the search time was the shortest, and the energy consumption was also the lowest. Especially in the complex level 4 wave water environment, the AIPSO algorithm had the best adaptability and robustness, and the robot had the highest working efficiency and comprehensive performance. The experimental results revealed that the AIPSO algorithm effectively improved the path search and garbage cleaning efficiency of the robots and reduced the working time, which further verified the reliability and accuracy of the designed algorithm.
      PubDate: Thu, 08 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0181605
      Issue No: Vol. 14, No. 2 (2024)
       
  • Damage characteristics of ribbed cylinder in motion under near-field
           underwater explosion

    • First page: 025218
      Abstract: The damage characteristics of a ribbed cylinder in the torpedo compartment shell is explored. An arbitrary Lagrange–Euler method is used to establish the fluid–structure interaction model for analyzing the ribbed cylinder’s response under near-field underwater explosion while in motion. The influence of detonation direction and standoff distance on the dynamic response of the moving ribbed cylinder is considered. The investigation reveals that the cylinder’s motion causes an uneven distribution of bubble load and secondary load, stemming from cavitation zone collapse, on the shell. This imbalance leads to a notable deflection difference between the shell’s front and rear sections, with maximum deformation concentration at the rear. In addition, in comparison to the lateral condition, static state analysis shows reduced average deflection and increased maximum deflection when the explosion point is above or below the shell, while in the sailing state, both average and maximum deflections increase. Notably, when the charge radius is between 6 and 15 times, the average damage rate in the sailing state consistently remains lower than that in the stationary state, while the maximum damage rate is higher at a specific burst distance.
      PubDate: Thu, 08 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189360
      Issue No: Vol. 14, No. 2 (2024)
       
  • Effect of mixed basalt fibers and nano-silica on mechanical properties and
           microstructure of recycled aggregate concrete

    • First page: 025219
      Abstract: In this study, basalt fibers (BFs) and nano-silica (NS) were innovatively combined to reinforce recycled aggregate concrete (RAC) to prepare recycled aggregate concrete (named NBRAC) with better mechanical and microstructural properties as an alternative to ordinary concrete. Different NBRAC specimens were prepared by adjusting the contents of NS and BF; the damage mechanism and mechanical properties of NBRAC were investigated; and the compressive, split tensile, and flexural strengths of NBRAC were evaluated. The microstructure of NBRAC was analyzed by scanning electron microscopy observation. The results showed that the densification of NBRAC was improved under the condition of 50% RA substitution rate and that its compressive, split tensile, and flexural strengths were increased by 6.8%, 16.3%, and 32.7%, respectively, compared with that of natural concrete, which proved that the method was feasible for the preparation of high-performance RAC. Scanning electron microscope image analysis confirmed the improvement effects of NS and BF on RAC, and combined with the experimental data, a composite explanation for the improvement effects of NS and BF on RAC was proposed for the first time.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0181863
      Issue No: Vol. 14, No. 2 (2024)
       
  • Effect of sulfate erosion on shear characteristics of slurry-reinforced
           coal body structural faces

    • First page: 025220
      Abstract: To study the effect of sulfate ion erosion on grouted reinforced coal bodies, downhole grouting reinforcement was simulated by artificially prefabricating regular serrated structural surfaces and grouting them with cement. In addition, sulfate erosion tests were carried out at three erosion ion concentrations (3%, 5%, and 10%) and four erosion times (7d, 14d, 28d, and 40d) at a pressure of 0.2 MPa using self-developed constant pressure accelerated erosion equipment, and then, mechanical property tests were conducted using an MTS816 rock mechanics shear tester, which is the most effective way to test the mechanical properties of coal. The test results are as follows: (1) the shear stress–displacement curves of the specimens were of slip type at lower normal stresses and of peak shear type at higher normal stresses, (2) the shear strength of the specimen was linearly negatively correlated with the erosion time and erosion ion concentration, (3) the effect of erosion time was greater than the effect of erosion concentration on the specimen shear strength parameters, (4) sulfate erosion can only affect the degree of shear shrinkage and shear rise and cannot change the damage behavior, and (5) with an increase in erosion ion concentration and the prolongation of the erosion time, the damage morphology of the specimen was shown as the “coal body destruction–nipping fracture–climbing nipping fracture” (coal–pulp interfacial separation) damage form.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0186066
      Issue No: Vol. 14, No. 2 (2024)
       
  • Thermal simulation and optimization of a Curie-based thermomagnetic motor
           harnessing concentrated solar energy

    • First page: 025221
      Abstract: This work reports on a numerical study of a thermomagnetic motor with the active material being a Nickel (Ni) plate using the Curie effect. The main goal is to use thermal simulation and parameter optimization to increase the motor’s efficiency. With respect to beam width, heat exposure duration, and rotation frequency, the study focuses on multiparametric simulations of a thermomagnetic wheel exposed to a concentrated sun beam. An efficient configuration for real-world application is found using the finite element-based computational tool COMSOL Multiphysics. The outcomes show that, when taking into account n = 5 cycles, the ideal configuration displays parameter settings with the lowest quadratic deviation around the Curie temperature during the thermal excitation process and the lowest quadratic deviation around the ambient temperature during the thermal relaxation process. Furthermore, a cooling method is presented, which includes supporting the active material with an Aluminum (Al) heat sink. In order to speed up the remagnetization of the Curie wheel, this method seeks to decrease heat accumulation and regulate the deposited thermal flux on the Ni plate. We also found that the reduction in quadratic deviation is most pronounced between zAl = 1 mm and zAl = 2 mm. At zAl = 10 mm, the quadratic deviation achieves its lowest value (σθmin=5.65K) at the end of the thermal relaxation process. The results of this study will forward the design of a high-performance thermomagnetic motor for mechanical and electrical applications.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0182779
      Issue No: Vol. 14, No. 2 (2024)
       
  • High-frequency magnetic response of crystalline and nanocrystalline
           antiferromagnetic NiO

    • First page: 025222
      Abstract: Performing micromagnetic simulations, we study the efficiency of response of bulk and polycrystalline nickel oxide (NiO) to high-frequency (up to 100 GHz) magnetic fields with relevance to potential application of the antiferromagnet as a core material to high-frequency coils and resonators. NiO is advantageous due to its insulating property and high Néel temperature. Though the dynamical susceptibility of the antiferromagnet is low, the achievable product of susceptibility and frequency (“performance factor”) appears to be relatively high, comparable to that of previously considered superferromagnetic systems. This makes NiO a potential core material for operating at extremely-high (sub-THz) frequency. The influence of thermal fluctuations on the susceptibility is estimated to be weak up to room temperature even for a nanocrystalline antiferromagnet, whereas, the magnetic response is linear for much wider ranges of frequencies and field amplitudes than for ferromagnetic and superferromagnetic systems.
      PubDate: Mon, 12 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000781
      Issue No: Vol. 14, No. 2 (2024)
       
  • Simulation analysis on magnetic core loss characteristic of valve reactor
           in UHVDC system

    • First page: 025223
      Abstract: Valve reactors (VR) with multiple magnetic cores are important electrical components in ultra-high voltage direct current systems. The impact current and high-order harmonics during their operation can lead to additional losses and temperature rise in the valve reactors, posing a threat to insulation aging, and even causing serious incidents such as combustion and explosions. Therefore, it is necessary to accurately quantify and analyze the loss characteristics of valve reactors under different magnetic materials. This article first theoretically analyzes the electromagnetic and temperature characteristics during the actual operation of VR; then, it analyzes and calculates the magnetic field distribution and electromagnetic losses of a single magnetic core. Finally, it establishes a three-dimensional equivalent model of VR and conducts transient electromagnetic-thermal coupled finite element simulation to reveal the magnitude and spatial distribution of VR temperature changes.
      PubDate: Mon, 12 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000827
      Issue No: Vol. 14, No. 2 (2024)
       
  • Implementing bidirectional logic with backhopping in magnetic tunnel
           junctions

    • First page: 025224
      Abstract: A bidirectional logic gate has been designed based on the backhopping phenomenon observed in magnetic tunnel junctions (MTJ) at high bias. The magnetization dynamics of each magnetic layer of the MTJ—having materials and geometry of a standard spin-transfer torque magnetic random access memory device—is calculated using the coupled Landau–Lifshitz–Gilbert equation-based theoretical framework. A circuit design interconnecting the MTJs has been proposed to simulate a two-input NAND gate. The results in both forward and reverse directions agree well with those found from the Boltzmann distribution, thereby demonstrating the equiprobability of all valid states.
      PubDate: Tue, 13 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0169751
      Issue No: Vol. 14, No. 2 (2024)
       
  • Tuning of magnetosplamon coupling between graphene scatterers for the
           optimal design of adjustable metasurfaces

    • First page: 025225
      Abstract: The resonance characteristics of magnetically-biased graphene micro-scatterers are thoroughly investigated in the present work using both eigenvalue and full-wave solvers. Initially, the graphene surface conductivity is presented in a tensor form due to the application of a magnetostatic bias field, which is perpendicular to the material’s surface. Then, the simple case of a graphene disk scatterer is examined, and a properly modified eigenvalue formulation is utilized to extract the plasmonic fundamental frequencies. The validity of the modal analysis is verified via a full-wave analysis that involves a plane-wave propagation and the extraction of the subsequent absorption cross-section utilizing the Finite-Difference Time-Domain method. Additionally, the dependence of a single disk scatterer resonances with the magnetostatic bias is evaluated, highlighting that as the bias field is increased, every edge mode degenerates into two sub-modes with an augmented difference between the resonant frequencies. Finally, the plasmonic coupling between adjacent scatterers is studied considering a periodic arrangement, similar to a metasurface, indicating the additional coupling modes as well as the adjustability of the properties with multiple degrees of freedom.
      PubDate: Wed, 14 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000808
      Issue No: Vol. 14, No. 2 (2024)
       
  • Effect of Ta buffer layer on the structural and magnetic properties of
           stoichiometric intermetallic FeAl alloy

    • First page: 025226
      Abstract: The magnetostructural phase transition in Fe50Al50 alloy with chemically ordered paramagnetic B2 and disordered ferromagnetic (FM) A2 phase has applications in spintronics such as phase-change magnetic memory and magnonic devices. We first conducted a systematic first-principles density functional theory study of the A2 and B2 phases in the Fe50Al50 alloy. A theoretical understanding of this equiatomic alloy’s electronic and spin-dynamical properties leads us to the experimental exploration of the FM A2 phase. Therefore, we deposit the 50 nm Fe50Al50 alloy thin film using sputtering and investigate the influence of the Ta buffer layer on its structural and magnetic properties. Our results reveal that the film with a buffer layer exhibits the A2 phase with appreciably higher saturation magnetization (848 emu/cc) than the film without a buffer layer (576 emu/cc). However, the surface roughness and Gilbert damping (α) slightly increase with the presence of the buffer layer from 0.41 to 0.56 nm and 4.35 × 10−3–4.94 × 10−3, respectively. The enhancement in α is due to extrinsic contributions induced by surface inhomogeneities.
      PubDate: Wed, 14 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000812
      Issue No: Vol. 14, No. 2 (2024)
       
  • An efficient spectral collocation method based on the generalized Laguerre
           polynomials to multi-term time fractional diffusion-wave equations

    • First page: 025227
      Abstract: In this study, a spectral collocation method is proposed to solve a multi-term time fractional diffusion-wave equation. The solution is expanded by a series of generalized Laguerre polynomials, and then, by imposing the collocation nodes, the equation is reduced to a linear system of algebraic equations. The coefficients of the expansion can be determined by solving the resulting system. The convergence of the method is proved, and some numerical examples are presented to demonstrate the accuracy and efficiency of the scheme. Finally, conclusions are given.
      PubDate: Wed, 14 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0187493
      Issue No: Vol. 14, No. 2 (2024)
       
  • Material gradation effects on twisting statics of bi-directional
           functionally graded micro-tubes

    • First page: 025228
      Abstract: This study aims to characterize the twisting behavior of bi-directional functionally graded (FG) micro-tubes under torsional loads within the modified couple stress theory framework. The two material properties involved in the torsional static model of FG small-scale tubes, i.e., shear modulus and material length scale parameter, are assumed to possess smooth spatial variations in both radial and axial directions. Through the utilization of Hamilton’s principle, the governing equations and boundary conditions are derived, and then, the system of partial differential equations is numerically solved by using the differential quadrature method. A verification study is conducted by comparing limiting cases with the analytical results available in the literature to check the validity of the developed procedures. A detailed study is carried out on the influences of the phase distribution profile and geometric parameters upon twist angles and shear stresses developed in FG micro-tubes undergoing external distributed torques.
      PubDate: Wed, 14 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0194270
      Issue No: Vol. 14, No. 2 (2024)
       
  • Electromagnetic analysis of permanent magnet-assisted synchronous
           reluctance motor based on magnetic equivalent circuit

    • First page: 025229
      Abstract: As rare-earth permanent magnet prices continue to fluctuate, interest in non-rare-earth permanent magnet-assisted synchronous reluctance motors (PMa-SynRMs) is increasing. However, non-rare-earth PMa-SynRMs have a multi-layer structure with interior permanent magnets to compensate for the low magnetic fields. Therefore, the rotor has several design parameters, and electromagnetic analysis is time-consuming. To overcome these challenges, magnetic equivalent circuit analysis was used to perform fast electromagnetic analysis of non-rare-earth PMa-SynRMs. In addition, the validity of the proposed method was confirmed through a comparison of the obtained results with those of finite element analysis.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000711
      Issue No: Vol. 14, No. 2 (2024)
       
  • Mathematical programming model for cost-optimized and environmentally
           sustainable supply chain design

    • First page: 025230
      Abstract: Sustainability is becoming increasingly important as a topic in general supply chains and cold chains. This study addresses the critical need for an integrated and comprehensive approach to supply chain design that simultaneously maximizes cost efficiency and incorporates environmental sustainability, focusing specifically on cold chains. Prior research has identified a gap in existing studies, highlighting the absence of an overarching framework from the logistics providers’ perspective. Our novel mathematical programming model introduces a unique strategy that carefully balances environmental concerns and cost optimization, addressing the shortcomings found in previous works. By integrating variables related to distribution, transportation, and inventory management, the model aims to minimize overall expenses and environmental impact, specifically regarding energy consumption and carbon emissions. We formulate and solve the optimization problem through rigorous mathematical programming, offering a flexible solution applicable to various logistics scenarios. The results demonstrate a significant reduction in overall expenses and environmental effects, providing logistics providers with a powerful tool for informed decision-making and sustainable supply chain management. This research contributes to the evolving field of supply chain sustainability by presenting a practical and effective model for maximizing cost savings while promoting environmental responsibility. The study concludes with compelling statistics, revealing a noteworthy decrease in overall expenses by €25 128 146.73 (100.25%) and environmental impact by 17 359.39 (100.04%). The outcomes show a notable decrease in general expenses and environmental effects, giving logistics providers a strong instrument for wise choices and sustainable supply chain management.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0192256
      Issue No: Vol. 14, No. 2 (2024)
       
  • Investigation of complex hyperbolic and periodic wave structures to a new
           form of the q-deformed sinh-Gordon equation with fractional temporal
           evolution

    • First page: 025231
      Abstract: This paper presents the fractional generalized q-deformed sinh-Gordon equation. The fractional effects of the temporal derivative of the proposed model are studied using a conformable derivative. The analytical solutions of the governing model depend on the specified parameters. The resulting equation is studied with two integration architectures: the sine-Gordon expansion method and the modified auxiliary equation method. These strategies extract hyperbolic, trigonometric, and rational form solutions. For appropriate parametric values and different values of fractional parameter α, the acquired findings are displayed via 3D graphics, 2D line plots, and contour plots. The graphical simulations of the constricted solutions depict the existence of bright soliton, dark soliton, and periodic waves. The considered model is useful in describing physical mechanisms that possess broken symmetry and incorporate effects such as amplification or dissipation.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0191869
      Issue No: Vol. 14, No. 2 (2024)
       
  • Design of dual loop controller for boost converter based on PI controller

    • First page: 025232
      Abstract: Boost converters are widely used in industry for many applications, such as electrical vehicles, wind energy systems, and photovoltaic energy systems, to step up the low voltages. Using the topology structure of the DC–DC boost circuit, this paper studied and designed a dual loop control method based on proportional integral controllers for improving the converter efficiency. The inner loop and outer loop controls of the traditional boost circuit are adopted in MATLAB/Simulink software to make the output of the system more stable. The input voltage is set to 24 V DC, and the desired output voltage varies from 36 to 48 V. Through simulation verification, the influence of a 1 kW sudden load connection by using a switch at a nominal output voltage of 48 V DC is studied, and the results show that it reduces the transient output voltage dips during the sudden load connection. Simulation analysis verifies the design scheme of the system, reduces the fluctuation in output voltage and power, reduces the output current ripple, minimizes the dip in voltage to a minimum possible value, and improves the dynamic characteristics and overall efficiency of the converter.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0191079
      Issue No: Vol. 14, No. 2 (2024)
       
  • Logistic regression analysis of mRNA expression changes and prognosis
           after cervical surgery

    • First page: 025233
      Abstract: Objective: The aim of this study was to investigate the diagnostic value of HPV (human papillomavirus) E6/E7 mRNA combined with thin-layer liquid-based cytology test (TCT) detection in patients with cervical intraepithelial neoplasia (CIN) in the residual and recurrence of lesions after cervical conization. Methods: A total of 154 patients who had undergone cervical conization and were diagnosed with high-grade cervical intraepithelial neoplasia (CIN 1 and CIN 3) by histopathology and had complete follow-up data were enrolled. TCT, HPV-DNA detection, and HPV E6/E7 mRNA detection combined with TCT detection in 12 months can be used to detect abnormal cytology (>atypical squamous epithelium of undetermined significance). Patients with atypical squamous cell of undetermined significance or high-risk HPV-DNA (+) or HPV E6/E7 mRNA combined with TCT (+) underwent colposcopy and cervical biopsy again for pathological diagnosis. Results: There were 9 cases of residual lesions and 22 cases of recurrence. Thirty of the 57 cases with positive HPV-DNA after surgery were still there or came back. Of the 26 cases with positive HPV E6/E7 mRNA combined with TCT, 24 were still there or came back. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy rate of HPV-DNA detection were 96.8%, 78.0%, 52.6%, 99.0%, and 81.8%, respectively; the sensitivity and specificity of HPV E6/E7 mRNA were combined with TCT detection of sex. Conclusion: HPV E6/E7 mRNA combined with TCT detection can be included in follow-up examinations, which can timely and effectively predict the risk of CIN residual or recurrence after cervical conization and reduce excessive examination and treatment.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0177033
      Issue No: Vol. 14, No. 2 (2024)
       
  • Optimizing ultra-wideband balanced power amplifiers through the selection
           of different output impedance transformation based on SiP techniques

    • First page: 025234
      Abstract: In this paper, two improved ultra-wideband (UWB) balanced power amplifiers based on the flip-chip system-in-package technique and electronic design automation (EDA) are proposed. The conventional approach to system-on-chip (SoC) involves integrating all sub-circuit designs into a single manufacturing process. However, in radio frequency circuits, adopting the SoC approach necessitates intricate matching designs, leading to an increase in development costs. In this study, two types of SiGe unit power amplifiers attempted to achieve a flat S21 response using simpler matching for input/output. The cascode architecture was adopted as the main structure for the first type of unit power amplifier (type I). Subsequently, the design of the second type unit power amplifier was built upon the foundation of the first type, with the only difference being the implementation of two parallel cascode structures (type II), and the primary goal is to enhance both gain and output power compared to the first type. In addition, for this second type unit power amplifier, in conjunction with a quadrature hybrid coupler, the optimal impedance matching value was selected to maintain the flatness of gain across the entire UWB range. Furthermore, the poor performance of S11,22 of these two types of unit power amplifiers was improved by using quadrature hybrid couplers using the WIPD process combined with EDA simulation. Therefore, using flip-chip packaging technology can effectively reduce the increased wafer fabrication costs caused by complex matching designs in active circuits. This improved system has the potential to offer a new practical application for UWB power amplifier design.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0194091
      Issue No: Vol. 14, No. 2 (2024)
       
  • Study on the construction of twisted cosine partially coherent beams and
           their propagation characteristics

    • First page: 025235
      Abstract: We propose a novel Schell model source for generating twisted partially coherent beams with an initial radius of curvature, which is called a twisted flat-topped cosine Gaussian Schell-model (TFCGSM) source. The TFCGSM beam comprises a wavefront phase and a flat-top structure, with the source degree of coherence determined by two cosine functions. Based on the Huygens–Fresnel principle, the general analytical expression of the cross-spectral density function of the TFCGSM beam propagating through the paraxial ABCD optical system is derived, and then its propagation properties are studied. The results show that the conversion of the array of the beam and the non-uniform structure can be realized by adjusting the parameters in the source plane. As the propagation distance of the TFCGSM beam increases, it rotates around the axis and increases the intensity of the array distribution. Surprisingly, the initial radius of curvature can cause the beam to rotate. The unique shape and properties of the TFCGSM beam create new possibilities for optical communication and enhanced optical functions.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0186514
      Issue No: Vol. 14, No. 2 (2024)
       
  • Suppressing galloping-induced vibrations by integrating bluff body with
           surface protrusions

    • First page: 025236
      Abstract: As a kind of self-excited large amplitude vibration, galloping is detrimental to engineering structures. Therefore, how to effectively suppress it has been a crucial issue for both industry and academia. In this Letter, a passive method based on integrating rectangular prismatic bluff bodies with different surface protrusions is proposed to mitigate galloping-induced vibrations. Both wind tunnel experiments and numerical simulations prove the validity of this method. Moreover, computational fluid dynamics simulations are also performed to investigate the underlying aerodynamic phenomena. Results reveal that the maximum amplitude and energy suppression ratios can reach 100%, especially for wind speeds higher than 3 m/s. As opposed to previous methods that delay galloping vibrations to higher wind speeds, this technique can directly change the vibration type from conjoint vortex-induced vibration (VIV)-galloping to VIV, which fundamentally eliminates galloping oscillations. Therefore, this method is promising in suppressing galloping vibrations.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0176781
      Issue No: Vol. 14, No. 2 (2024)
       
  • Generation of highly anisotropic physical properties in ferromagnetic thin
           films controlled by their differently oriented nano-sheets

    • First page: 025237
      Abstract: We fabricated ferromagnetic nano-crystalline thin films of Co, Fe, Co–Fe and Co-rich and Fe-rich, Co–MT and Fe–MT (MT = transition metal), constituted by nano-sheets with a controlled slant. Visualization of these nano-sheets by Scanning Tunneling Microscopy and High-Resolution Transmission Electron Microscopy (HRTEM) showed typically tilt angles ≈56° with respect to the substrate plane, and nano-sheets ≈3.0–4.0 nm thick, ≈30–100 nm wide, and ≈200–300 nm long, with an inter-sheet distance of ≈0.9–1.2 nm, depending on their constitutive elements. Induced by this nano-morphology, these films exhibited large uniaxial magnetic anisotropy in the plane, the easy direction of magnetization being parallel to the longitudinal direction of the nano-sheets. In the as-grown films, typical values of the anisotropy field were between Hk ≈ 48 and 110 kA/m depending on composition. The changes in the nano-morphology caused by thermal treatments, and hence in the anisotropic properties, were also visualized by HRTEM, including chemical analysis at the nano-scale. Some films retained their nano-sheet morphology and increased their anisotropies by up to three times after being heated to at least 500 °C: for example, the thermal treatments produced crystallization processes and the growth of CoV and CoFe magnetic phases, maintaining the nano-sheet morphology. In contrast, other annealed films, Co, Fe, CoZn, CoCu… lost their nano-sheet morphology and hence their anisotropies. This work opens a path of study for these new magnetically anisotropic materials, particularly with respect to the nano-morphological and structural changes related to the increase in magnetic anisotropy.
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000813
      Issue No: Vol. 14, No. 2 (2024)
       
  • Antibacterial properties of magnesium oxide nanoparticles and their
           composites

    • First page: 025238
      Abstract: Many different disciplines are very much interested in the antibacterial qualities of magnesium oxide nanoparticles (nano-MgO) and their composites. The mechanics behind these qualities and their uses will be covered in detail in this exposition. Although nano-particulate magnesium oxide (nano-MgO) has received much interest as an antibacterial agent, its exact antibacterial mechanisms are still not fully understood, requiring more in-depth research in the areas of stability, processability, and safety. There is a discernible trend in the field of antibacterial materials that combines conventional materials with natural elements. As a newly developed ceramic antibacterial agent with distinct antibacterial properties and a wide range of uses, nano-MgO has become a major area of research interest. As a result, this paper summarizes the many approaches to synthesizing nano-MgO powder, analyzes its antibacterial properties, and offers a current assessment of new developments in the field and composite manufacturing methods. Moreover, it carefully points out common problems and suggests directions for future study. It is essential to the search for cutting-edge antibacterial materials because of its many qualities and wide range of potential uses. NanoMgO will play an essential role in determining the direction of antibacterial agents in the future, given the mounting concern over antibiotic resistance and the demand for environmentally friendly substitutes. This study explores the subtleties of nano-MgO and antibacterial activity in the realm of antibacterial materials. While navigating the complexities of a changing world, understanding and harnessing the potential of nano-MgO is vital for promoting healthier and more sustainable living environments.
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0171608
      Issue No: Vol. 14, No. 2 (2024)
       
  • Phase stability of a eutectic high entropy alloy under extremes of
           pressures and temperatures

    • First page: 025239
      Abstract: Additively manufactured high-entropy alloys are of interest because of their unique combination of high yield strength and large ductility achieved with far-from-equilibrium crystalline phases and micro/nanostructure morphology. We report on the phase transformation and thermal equation of state of the eutectic high-entropy alloy (EHEA) Al18Co20Cr10Fe10Ni40W2, produced by laser powder-bed fusion (L-PBF). The EHEA was studied in a large-volume Paris–Edinburgh cell using energy-dispersive x-ray diffraction to a pressure of 5.5 GPa and a temperature of 1723 K. Static compression studies in diamond anvil cells using angle-dispersive x-ray diffraction extended the high-pressure structural data to 317 GPa at ambient temperature. The initial dual-phase nanolamellar face-centered cubic (FCC) and body-centered cubic (BCC) structure of Al18Co20Cr10Fe10Ni40W2 transforms into a single FCC phase under high pressure, with the BCC-to-FCC phase transformation completing at 9 ± 2 GPa. The FCC phase remained stable up to the highest pressure of 317 GPa. The measured thermal equation of state for the FCC phase of Al18Co20Cr10Fe10Ni40W2 is presented up to 5.5 GPa and 1473 K. We observed melting of the EHEA at 1698 ± 25 K at a pressure of 5.5 GPa, and the recrystallized sample shows an increased fraction of the CsCl-type (B2) phase at ambient conditions following release from the high-pressure high-temperature state. The BCC-to-FCC phase transition completion pressure is correlated with the nanolamellae thickness of the BCC layer in this diffusion-less transformation at ambient temperature.
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0188644
      Issue No: Vol. 14, No. 2 (2024)
       
  • GPU parallel computing based on PF-LBM method for simulating dendrites
           growth under natural convection conditions

    • First page: 025240
      Abstract: This study introduces a GPU-based parallel computing approach that combines the phase-field model (PF) and the lattice Boltzmann model (LBM). By establishing a coupled multiphase field model incorporating physical external fields such as flow field, temperature field, and solute field, the research simulates the growth of single grains and multiple grains under the influence of natural convection. The variations in dendritic morphology, flow field, and solute field during dendritic solidification processes are observed. Initially, the study analyzes the morphology of equiaxed dendrites and the growth patterns of primary dendrites arms under natural convection conditions. The evolution of equiaxed dendrites in single grains and multiple grains under various conditions is investigated. Furthermore, the study explores the impact of different anisotropy strengths on the growth of single grains and multiple grains under natural convection. Notably, a distinct “necking” phenomenon is observed when the anisotropy strength of a single grain is 0.05. In the case of multiple grains, where competition between dendrites is present in addition to the influence of natural convection, a pronounced “necking” phenomenon is evident at an anisotropy strength of 0.03. Moreover, OpenCL parallel technology is designed on the GPU platform to accelerate the solution of the model. The parallelization of the phase-field model coupled with the LBM model on the GPU demonstrates a clear advantage. The parallel computation based on GPU not only exhibits absolute superiority but also shows more significant acceleration effects as the computational domain increases.
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0194466
      Issue No: Vol. 14, No. 2 (2024)
       
  • Numerical analysis of the powder mixed electrical discharge machining
           

    • First page: 025241
      Abstract: The powder mixed electrical discharge machining (PMEDM) process was simulated via finite element analysis in the current study to assess heat behavior and material removal rate. The goal of this paper is to conduct a thorough experimental and thermal examination of electrical discharge machining (EDM) in order to forecast its cutting characteristics and subsequently optimize the output variables using a response surface methodology for simulations and choosing the most suitable set of process variables related to the PMEDM process. This study’s objective is to design a 2D axisymmetrical transient thermal model that might also describe the physics of material removal in a single spark PMEDM operation on a Titanium Zirconium Molybdenum (TZM) superalloy. ANSYS (version 9.1) software is used to perform transient heat transfer simulations to determine the temperature profile with the amount of material removal at different current, pulse on and off times, gap voltages, and fraction of heat that enters the specimen. The PMEDM process produced craters with a lower diameter and depth, which increased the material removal rate and enhanced the surfacing quality. Compared to the conventional EDM process, the inclusion of powder raised the heat flux given to the work material by 10%–12%. It has been determined that with the single spark modeling technique, the temperature significantly dropped in both the radial and depth directions. The computational results are compared with experimental observations for similar machining conditions, and both results agree satisfactorily.
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0188809
      Issue No: Vol. 14, No. 2 (2024)
       
  • Design and implementation of user task offloading algorithm

    • First page: 025242
      Abstract: After the service provider temporarily selects the required edge nodes based on social and storage capabilities, application execution causes the edge nodes to cache part of the application data. Therefore, offloading part of the application computing tasks to the selected edge nodes can effectively improve application execution performance. However, in cases where the resources of user’s IoT devices are insufficient, tasks can be further offloaded to traditional edge servers or even to the cloud to maximize application execution efficiency. In this paper, the entire uninstall utility is modeled as a weighted sum of task completion time and energy consumption. Under the premise of considering users’ preferences for completion time and energy consumption, a game-based uninstallation algorithm is proposed. The algorithm performs uninstallation by optimizing the uninstallation decision. Based on user preferences, the total system overhead is relatively small. The subsequent simulation experiments show that the algorithm can reduce system overhead on the basis of satisfying user preferences and has relatively good adaptability.
      PubDate: Wed, 21 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0181636
      Issue No: Vol. 14, No. 2 (2024)
       
  • Polynomial chaos expansion for sensitivity analysis of two types of
           transmission line models

    • First page: 025243
      Abstract: This paper presents two sensitivity analyses, one of which is for the time-domain transmission line (TL) model using the latest weight-based algorithm that is a combination of the coherence-optimal sampling (COS) and the l1-minimum problem (l1-M) and the other is for the high-frequency field line coupling model based on the algorithm that combines the Latin hypercube sampling (LHS) with the l1-M for the first time, where the COS and the LHS are employed to draw samples and the polynomial chaos expansion (PCE) coefficients are obtained by solving the l1-M. Both algorithms are within the PCE framework. The results show that for the time-domain TL model, the capacitance has the greatest impact on the voltage response, followed by the resistance. The height and the radius have the least impact, while there is little difference between them. For the high-frequency field line coupling model, the azimuth angle has the greatest impact on the current in the TL, followed by the elevation angle. The terminal load, the conductivity, the field amplitude, the relative permittivity, and the TL radius have the least effect, and there is little difference among them. Additionally, both algorithms only require no more than 0.60% of the total Monte Carlo (MC) computation time when yielding solutions with almost identical accuracy. Compared to performing a sensitivity analysis using the MC method, the use of two algorithms significantly improves efficiency.
      PubDate: Wed, 21 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0191506
      Issue No: Vol. 14, No. 2 (2024)
       
  • A computational model of the human colon for use in medical robotics

    • First page: 025244
      Abstract: This paper reports on the results of modeling the human colon and analyzes its effectiveness as a finite element analysis (FEA) tool for testing conventional and robotic colonoscope technologies. FEA has been used to model colon tissue before, but these analyses have been carried out on smaller tissue samples, such as to fit strain energy functions to mechanical testing data or to explore the inflation-extension response of a section of the colon. The full colon has not yet been modeled in this way, and this study aims to show the usefulness of such a tool for testing endoscopic devices for diagnostic and therapeutic purposes in the colon. Data from the literature and databases have been used to approximate the stress response of the tissues, and a critical analysis of the limitations of the approximations has been carried out. Characteristic colonoscope loops were created to analyze the mechanical response of the colon and provide comparable results to conventional colonoscopy. The results showed how stress would be propagated along the length of the colon and how neighboring structures can affect the stresses and strains experienced by the colon wall, demonstrating the need for and capabilities of a full FEA model of the colon to test endoscopic devices.
      PubDate: Wed, 21 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0179544
      Issue No: Vol. 14, No. 2 (2024)
       
  • Wire texture C-axis distribution of strontium ferrite/PA-12 extruded
           filament

    • First page: 025245
      Abstract: The magnetic anisotropy of strontium ferrite (SF)/PA12 filament, a popular hard magnetic ferrimagnetic composites that is used for 3D-printing of permanent magnets, is studied by vibrating sample magnetometry. The studied filaments have a composition of SF/PA-12 thermoplastic composite with a 40% wt.  ratio of SF. SF particles are non-spherical platelets with an average diameter of 1.3 um and a diameter to thickness ratio of 3. Filaments are produced by a twin-screw extruder and have a diameter of 1.5 mm. SEM images show that the SF particles are homogeneously distributed through the filament. VSM measurements on different parts of the filaments show that the outer part of the cylindrical filament has a higher anisotropy, and the core is mostly isotropic. This conclusion is consistent with computational work by others which suggest that particle alignment predominantly takes place near the walls of the extruder die where shear flow is maximum. Additional hysteresis curve measurement of the outer cylindrical part of the filament parallel to the r and ϕ directions indicates that the squareness of the hysteresis curve (S) is larger in the r-direction. This indicates that the outer surface of the filament has a strong easy axis in the r-direction. We conclude that the SF platelets line up parallel to the walls of the extrusion die.
      PubDate: Thu, 22 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000701
      Issue No: Vol. 14, No. 2 (2024)
       
  • Effect of processing parameters on the defects, microstructure, and
           property evaluation of Ti-6Al-4V titanium alloy processed by laser powder
           bed fusion

    • First page: 025246
      Abstract: In this study, we designed the processing windows for laser powder bed fusion (LPBF) of Ti-6Al-4V (Ti-64) alloy by using central composite design and made a detailed investigation into the influence of processing parameters on the defects. The purpose is to investigate the effect of defects on mechanical properties. It was found that insufficient energy density could lead to the formation of lack of fusion (LOF) defects and produce non-melted powders on the surface, while excessive energy density could lead to cracks that were detrimental to mechanical performance. In addition, the microstructural evaluation found that relatively low energy density could lead to shorter columnar prior-β grains, while prior-β grains in the sample processed by the high energy density extended almost the entire height of the cross-section, which could lead to the strong mechanical property anisotropy. The prior β grains are formed by heterogeneous nucleation on the partially melted material powder. As the energy input increases, all the powder powders in the molten pool can be melted so that these particles do not act as nucleation sites and the prior β grain can grow through more layers without forming new grains being able to nucleate. The prior β-grain in as-built Ti-64 samples consisted of acicular α’ martensite with myriads of lattice distortions, as a precursor to a phase transition, which lead to strong tensile strength and poor ductility. Annealing heat treatment promoted the improvement of the ductile performance of LPBF Ti-64. Overall, this study provides comprehensive views on the effects of processing parameters (laser power, scanning speed, and hatch distance) on the internal (pores and LOF) and external (unmelted powder, sintering neck, and crack), defects, microstructure, and tensile property evaluation of LPBF Ti-64, which offer insights for the development of additive manufactured titanium alloys with excellent mechanical property.
      PubDate: Thu, 22 Feb 2024 00:00:00 GMT
      DOI: 10.1063/7.0001251
      Issue No: Vol. 14, No. 2 (2024)
       
  • A theoretical study of hybrid hydrogen adsorption: Mg
           nanoparticle-inserted Mg-MOF-74

    • First page: 025247
      Abstract: Metal-organic frameworks (MOFs) provide highly selective catalytic activity due to their porous crystalline structure. There is particular interest in metal nanoparticle-MOF composites (M NP@MOF) that could take advantage of synergistic effects for enhanced catalytic properties. We present an investigation into the local structure and electronic properties of Mg NP@Mg-MOF-74, which is composed of Mg nanoparticles and Mg-MOF-74. A theoretical study on the adsorption of multiple Mg2–Mg10 clusters at one pore in a 1 × 1 × 2 Mg-MOF-74 supercell is conducted, clearly showing that the small clusters tend to aggregate together when stabilized by bonds between Mg and O in the MOF. Considering the size and shape of the pore in the MOF, HCP-Mg nanoparticles with 60 Mg atoms are embedded in one pore of 1 × 1 × 2 Mg-MOF-74 to form nanowires. Results show that the mixture Mg NP@Mg-MOF-74 exhibits a better hydrogen adsorption performance than the isolated Mg nanoparticle, with a considerable estimated theoretical hydrogen storage capacity of 3.98 wt. %. The corresponding electronic structure analysis reveals that the accumulation of charges on H in the hybrid system is clearly enhanced with respect to the isolated Mg nanoparticles.
      PubDate: Mon, 26 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0193231
      Issue No: Vol. 14, No. 2 (2024)
       
  • Spectral analysis of spin noise in an optically spin-polarized stochastic
           Bloch equation driven by noisy magnetic fields

    • First page: 025248
      Abstract: We theoretically analyze an optically spin-polarized collection of atoms, which serves as a basis for atomic sensors. Assuming that the intrinsic atomic spin projection noise is negligible, we provide the closed-form autocorrelation function and the power spectral density (PSD) of the solution to a noisy version of an optically pumped Bloch equation, wherein each component of the external magnetic field is subjected to white noise. We conclude that noise in the bias B-field direction does not affect the autocorrelation function, up to first order in white noise covariance amplitudes. Moreover, the noise terms for the remaining two axes make different contributions to the magnetic noise-driven spin PSD; in particular, the contribution corresponding to noises perpendicular to the probing direction dominates at high frequencies. Some results concerning the second (and higher)-order terms are given. In particular, we anticipate a decrease in the effective Larmor frequency despite an increase in the magnetic field magnitude in the case of anisotropic transversal B-field noises. The analytic results are supported by Monte Carlo simulations employing the Euler–Maruyama method. The analytic methodology is applied to the case of a Bell–Bloom magnetometer, which reveals a non-linearity in the PSD of the magnetometer output and also a broadening effect due to magnetic field noise.
      PubDate: Tue, 27 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0190271
      Issue No: Vol. 14, No. 2 (2024)
       
  • An information fractal dimensional relative entropy

    • First page: 025249
      Abstract: Shannon entropy is used to measure information uncertainty, while the information dimension is used to measure information complexity. Given two probability distributions, the difference can be measured by relative entropy. However, the existing relative entropy does not consider the effect of information dimension. To improve the existing entropy, a new relative entropy is presented in this paper. The information fractal dimension is considered in the proposed relative entropy. The new relative entropy is more generalized than the initial relative entropy. When dimension is not considered, it will degenerate to the initial relative entropy. Another interesting point is that the new relative entropy may have negative values when calculating. The physical meaning is still under exploration. Finally, some application examples are provided to exemplify the utilization of the proposed relative entropy.
      PubDate: Tue, 27 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189038
      Issue No: Vol. 14, No. 2 (2024)
       
  • Origin of microscopically coupled ferromagnetic Cu-ions in a distorted
           system of Cu-doped ZnO and their synchrotron-based electronic structures

    • First page: 025250
      Abstract: Spintronics-based studies have produced significant attention in the last decade while claiming the observation of room temperature ferromagnetism (RTFM). Nevertheless, there is a lack of consensus on a mechanism responsible for this phenomenon. In this study, we focus on Cu-doped ZnO (ZCO) to understand the microscopic origin of RTFM and the role of different oxidation states of Cu in RTFM. We have performed different spectroscopic techniques using synchrotron facilities. The values of spin-moment obtained from x-ray magnetic circular dichroism sum-rule truly exhibit a ferromagnetic interaction in the nanocrystalline powder of ZCO with ∼0.58 μB for 5% of Cu concentration in the total fluorescence yield mode. Such an enhanced magnetization is attributed to the presence of Cu2+, which is mainly localized in the bulk region. Cu in ZCO is mostly dominated by the presence of Cu2+. This is clearly reflected by the profiles of x-ray photoemission spectroscopy. Consequently, the weakly magnetized total electron yield mode is attributed to a state of magnetic frustration as the majority of Cu3+ is found on the surface. Some of these Cu3+ when come in the vicinity of Cu2+ ions result in a highly correlated state of double exchange mechanism, which is the microscopic origin of RTFM in ZCO. The coupling between Cu2+-Cu3+ is mediated via oxygen vacancies (VO), the presence of which is confirmed through the features of electron energy loss spectroscopy over different edges. The confirmation of VO is also supported by the deconvolution of E2high-phonon in the Raman spectra. Moreover, the defects in the local electronic structures of ZCO are demonstrated by the deconvoluted spectra of Cu L3 x-ray absorption spectroscopy. The images obtained from high-resolution transmission electron microscopy confirm the incorporation of Cu into the wurtzite crystal of ZnO. A clear enhancement in magnetization upon an increase in carriers of Cu in ZCO indicates carrier-induced ferromagnetism. Cu2+ and VO are the two attributes of RTFM in ZCO.
      PubDate: Wed, 28 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0179935
      Issue No: Vol. 14, No. 2 (2024)
       
  • A hybrid CNN–BiLSTM–AT model optimized with enhanced whale
           

    • First page: 025251
      Abstract: To further improve the remaining useful life forecasting accuracy of fuel cells using classic deep learning models, a convolutional neural network combining bidirectional long and short-term memory networks (BiLSTM) and attention mechanism (AT) is optimized with the enhanced whale optimization algorithm (EWOA). Singular spectrum analysis preprocesses the attenuation data to eliminate noise and enhance its effective information; the CNN–BiLSTM model extracts spatiotemporal features and learns historical and future information; AT further explores the spatiotemporal correlation; and EWOA optimizes its hyperparameters to reduce human intervention error. Results demonstrate that, compared with long and short-term memory, CNN–LSTM, CNN–BiLSTM, CNN–BiLSTM–AT, and CNN–BiLSTM–AT optimized with other algorithms, the CNN–BiLSTM–AT model optimized with EWOA achieves lower root mean square error, mean absolute error, mean absolute percentage error, and relative errors of 0.1951%–0.2059%, 0.1267%–0.1538%, 0.0319%–0.0366%, and 0.026%–0.036%, respectively, with different training data. Importantly, the proposed model still maintains good prediction robustness with over 40% of the missing data.
      PubDate: Wed, 28 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0191483
      Issue No: Vol. 14, No. 2 (2024)
       
  • A novel hybrid magnetic material based on three-phase saturated core fault
           current limiter

    • First page: 025301
      Abstract: Installing a three-phase saturated core fault current limiter (TSFCL) is an effective method to limit the increasing short-circuit current in high-voltage alternating current (HVAC) systems. However, the traditional TSFCL uses silicon steels as its working material for the iron core, resulting in poor current-limiting effects, requiring a large DC excitation current, and having a slow response speed. Nanocrystalline alloys have advantages such as a lower saturation point, higher permeability in the unsaturated zone, and a steep B–H curve, making them highly suitable for TSFCL’s applications. However, their poor capability which withstands fault hindered their large-scale commercialization. Therefore, this paper proposes a novel hybrid magnetic material based on TSFCL (HMTFCL), where the materials of the working limbs are replaced by nanocrystalline alloys. Compared to TSFCL, the DC excitation current of HMTFCL decreases by 60.5%. And, the HMTFCL reduces the peak short-circuit current by 23%. Last, the magnetic flux intensity inside the working limb of HMTFCL is reduced to zero more quickly.
      PubDate: Thu, 01 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000829
      Issue No: Vol. 14, No. 2 (2024)
       
  • Study of grain-patterned and highly ordered L1 0 -FePt HAMR media using
           reactive molecular dynamics method

    • First page: 025302
      Abstract: Embedded Mask Patterning (EMP) has been proposed as a cost-effective fabrication method to be capable of patterning sub-5-nm grain sizes for highly ordered L10-FePt media for Heat-Assisted Magnetic Recording (HAMR). Understanding the etching mechanism of FePt is critical to maintaining the highly ordered L10 structure and low damage to magnetic grains. In this research, a reactive Molecular Dynamics (MD) model is developed to study methanol (MeOH) plasma etching on highly ordered continuous L10-FePt media film. The model describes the reactive interaction mechanism between the plasma products CO/H2 molecules and Fe/Pt atoms. It shows the dominant Fe-C interaction upon the dissociation of CO ligands leads to formation of large and volatile Fen-C clusters contributing to high chemical etch yield.
      PubDate: Thu, 01 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000762
      Issue No: Vol. 14, No. 2 (2024)
       
  • Antimagnonics

    • First page: 025303
      Abstract: Magnons are the quanta of collective spin excitations in magnetically ordered systems, and manipulation of magnons for computing and information processing has witnessed the development of “magnonics.” A magnon corresponds to an excitation of the magnetic system from its ground state, and the creation of a magnon thus increases the total energy of the system. In this perspective, we introduce the antiparticle of a magnon, dubbed the antimagnon, as an excitation that lowers the magnetic energy. On the fundamental side, the introduction of antimagnons paves the way to study phenomena from high-energy physics that are hard to observe with elementary particles, such as the Klein effect, black-hole horizons, and black-hole lasing, in a condensed-matter setting. On the application side, the introduction of antimagnons yields physical intuition for schemes to amplify magnons that may eventually find applications in magnonics, and this is often based on analogies of the aforementioned high-energy phenomena. We investigate the stability and thermal occupation of antimagnons and verify our theory by micromagnetic simulations. We hope that our work stimulates fundamental interest in antimagnons, as well as their applications to spintronic devices.
      PubDate: Thu, 01 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0151652
      Issue No: Vol. 14, No. 2 (2024)
       
  • A study on acceleration of SP decoder using reliability of recording
           sequence by neural network based on parity check result in SMR system

    • First page: 025304
      Abstract: We study signal processing methods to realize ultra-high-density hard disk drives (HDDs). Among them, we have applied the neural network to improve decoding performance in low-density parity-check (LDPC) coding and iterative decoding in the shingled magnetic recording (SMR) system. In this study, we realize acceleration of the sum-product (SP) decoding by updating the decoding reliability of the SP decoding using the reliability of the recording sequence calculated by the neural network based on the parity check results. As a result, the proposed system achieved error-free with the fewest number of iterations in the SP decoder compared to our previous studies.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000710
      Issue No: Vol. 14, No. 2 (2024)
       
  • Data-cell-variation-tolerant triple sampling non-destructive
           self-reference sensing scheme of STT-MRAM

    • First page: 025305
      Abstract: Inevitable process variations (PVT) brought by both the magnetic tunneling junction (MTJ) and MOSFET based on the complementary metal-oxide semiconductor (CMOS) technology become a major obstacle for the mass production of spin transfer torque magnetic random access memory (STT-MRAM). The detriment of the process variations leads to a serious degradation in the fundamental yield with the shrinkage of the technology nodes. However, the conventional data-cell-variation-tolerant (DCVT) sense scheme cannot get the target read yield due to the limited sense margin (SM). To resolve this problem, a DCVT triple sampling non-destructive self-reference sensing scheme (TSNS) is proposed in the paper, which doubles the SM, with lower power consumption and better SM compared with the conventional DCVT sense scheme. Monte Carlo simulation with industry-compatible 65-nm model parameters results show that the proposed sensing scheme shows over 2.5 times higher SM and less power consumption compared to the previous self-reference circuit. The proposed sensing scheme can get the target read yield with lower power consumption.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000664
      Issue No: Vol. 14, No. 2 (2024)
       
  • Computational modelling of a triaxial vibrating sample magnetometer

    • First page: 025306
      Abstract: Magnetic Field Assisted Additive Manufacturing (MFAAM) enables 3D printing of magnetic materials of various shapes which exhibit a complex anisotropy energy surface containing contributions generated from different origins such as sample, particle, and agglomerate shape anisotropy, flow and field induced anisotropy, and particle crystal anisotropy. These novel magnet shapes require the need to measure the x, y, and z components of the magnetic dipole moment simultaneously to fully understand the magnetic reversal mechanism and unravel the complex magnetic anisotropy energy surface of 3D printed magnetic composites. This work aims to develop a triaxial vibrating sample magnetometer (VSM) by adding a z-coil set to a pre-existing biaxial VSM employing a modified Mallison coil set. The optimum size and location of the sensing coils were determined by modeling the sensitivity matrix of the z-coil set. The designed coil set was implemented using 3D printed spools, a manual coil winder, and gauge 38 copper wire. A 3D printed strontium ferrite nylon composite sample was used to estimate the sensitivity of the z-coils (50 mV/emu). The results herein are applicable for any VSM using a modified Mallison biaxial coil configuration allowing for a quick implementation on pre-existing systems.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000787
      Issue No: Vol. 14, No. 2 (2024)
       
  • A metal object detection system for electric vehicle wireless charging
           based on LC oscillating circuit and reverse-winding-incorporated detection
           coils

    • First page: 025307
      Abstract: In magnetically coupled wireless charging systems for electric vehicles, it is common for metal objects to enter the charging system. In this case, the strong magnetic field of wireless charging causes an eddy current effect in the metal object, which generates a large amount of heat. This heat accumulation poses a risk of fire. In this paper, a novel metal object detection system designed for wireless charging of electric vehicles is proposed. The system utilizes the principle that the coil impedance and coupling coefficient change with the presence of metal objects, and a set of composite coils is designed to improve the sensitivity of detection. The detection coil and feedback coil in the composite coil are decoupled by reverse series connection. An LC oscillating circuit based on transformer feedback is used to detect metal objects, and the circuit can make good use of the parameter changes of the composite coil. Finally, an experimental platform for wireless charging metal detection in electric vehicles has been built to validate the proposed system. Through testing, it has been demonstrated that the system can detect the presence of metal objects in a timely and accurate manner.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000673
      Issue No: Vol. 14, No. 2 (2024)
       
  • GdFe-based nanostructured thin films with large perpendicular magnetic
           anisotropy for spintronic applications

    • First page: 025308
      Abstract: In this study, we investigated the impact of geometric factors on the magnetic anisotropy of Gd-Fe alloy thin films deposited on nanoporous alumina membranes. By synthesizing Gd-Fe alloy nanostructure thin films with different hole diameters (ranging from 45 to 90 nm) and keeping the layer thickness and lattice parameters fixed at 45 nm and 105 nm, respectively, we observed a significant perpendicular magnetic anisotropy (PMA) in samples with hole diameter above 65 nm. The transition from in-plane to out-of-plane magnetization in Gd-Fe alloy nanostructure thin films occurred at a critical antidot hole diameter of 75 nm. The observed variations in coercivity and remanence with the nanohole diameter are attributed to substantial changes in the magnetization mechanisms induced by the nanoholes. This novel induction of PMA in Gd-Fe alloy nanostructure thin films through the manipulation of geometric parameters in the antidot arrays opens new possibilities for tailoring the magnetic behavior of ferromagnetic metals with pronounced PMA.
      PubDate: Fri, 02 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000728
      Issue No: Vol. 14, No. 2 (2024)
       
  • Structural and magnetic properties of he x agonal ferrite composites with
           planar and perpendicular anisotropy

    • First page: 025309
      Abstract: In the present work, composites of (x)SrFe12O19(SrM)/(1-x) Ba2Co2Fe12O22(Co2Y) [where x = 0.1, 0.2, 0.3, 0.4] were prepared by physical mixing method. The effect of exchange coupling between SrM and Co2Y phases on composites structural, morphological, and magnetic properties has been investigated. XRD patterns confirmed the co-existence of SrM and Co2Y phases with the presence of a secondary Co2Z phase. Smooth hysteresis loops without kink confirmed that SrM and Co2Y phases in composites are exchange-coupled and signify cooperative magnetic switching among M and Y phase spins. A linear increase in magnetization was observed with an increase in M-phase. On the other hand, a decrease in coercivity was observed due to strong intervening coupling between the phases. A single peak in the switching field distribution curve (SFD) of composites also confirm strong coupling between M and Y phases.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000668
      Issue No: Vol. 14, No. 2 (2024)
       
  • Improved faster R-CNN and adaptive Canny algorithm for defect detection
           using eddy current thermography

    • First page: 025310
      Abstract: Eddy current thermography (ECT) is a non-invasive testing method that combines electromagnetic induction and infrared thermography to identify flaws in materials that conduct electricity. However, ECT faces difficulties in accurately locating and classifying defects owing to its low signal-to-noise ratio and complex defect patterns. In this paper, we propose a new method that integrates an improved faster region-convolutional neural network (R-CNN) and an adaptive Canny algorithm to enhance the defect detection performance of ECT. An improved faster R-CNN is a deep neural network that can automatically detect and locate multiple defects in a single ECT image, whereas the adaptive Canny algorithm is an edge detection technique that can identify defect boundaries. The proposed method was tested using a dataset of ECT images with different types of defects. The results demonstrated that our method achieved better accuracy, precision, and speed than existing methods.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189084
      Issue No: Vol. 14, No. 2 (2024)
       
  • Terahertz quantum cascade laser frequency combs with engineered operation
           frequency around 4.0 THz

    • First page: 025311
      Abstract: Freely engineering the operation frequency of frequency comb sources is crucial for various applications, e.g., high-precision spectroscopy, ranging, communications, and so on. Here, by employing band structure simulations, group velocity dispersion (GVD) analysis, and experimental verifications, we demonstrate that the operation frequency of terahertz (THz) quantum cascade laser frequency combs can be engineered from 4.2 to 4.0 THz. First of all, from the viewpoint of the band structure engineering, we shift the frequency corresponding to the optical transitions in the active region from 4.2 to 4.0 THz by slightly altering the thicknesses of quantum wells. Meanwhile, a GVD analysis is applied to evaluate the potential comb performance. Finally, experimental characterizations, e.g., emission spectra, inter-mode beatnote, dual-comb operation, are performed to validate the exceptional comb operation at 4.0 THz. The advancement in simulations and experimental results present a comprehensive method to customize the desired THz radiative frequency for comb generation, which facilitates the practical development of broadband, high-precision THz comb sources.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0188322
      Issue No: Vol. 14, No. 2 (2024)
       
  • An insight into the solitonic structure of two distinct fractional
           nonlinear Schrödinger models in optical fiber using conformable
           fractional derivative

    • First page: 025312
      Abstract: The goal of this work was to use conformable fractional derivative sense to create some crucial solitary waves for two models of space–time fractional nonlinear Schrödinger equations. We use the unified solver approach to accomplish this goal in a fully unified way. This solution is robust, practical, dependable, and simple to use. The obtained solutions are extremely important for describing critical complicated phenomena in fractional quantum mechanics, optical fiber communications, and energy applications. Some simulations are provided to demonstrate the behavior of the obtained solutions when appropriate physical parameters are used. It was noted that by increasing the fractal factors, the nonlinear wave propagates with a changing phase and wave frequency. Our research may open up new possibilities for optical manipulation in practical applications. Finally, further fractional physical models can be solved using the suggested technique.
      PubDate: Mon, 05 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0187732
      Issue No: Vol. 14, No. 2 (2024)
       
  • Magnetoelectric CoV 2 O 6 —Role of Fe inter-play in Co-based Ising
           spin chain interactions

    • First page: 025313
      Abstract: CoV2O6, a Brannerite-type material, exists in both monoclinic (α) and triclinic (γ) forms. α- CoV2O6 exhibits quasi-1D ferromagnetic chains of octahedrally-coordinated Co2+ions in the higher spin state. Fe2+ doped α-CoV2O6 (3 mol%) single crystals were synthesized using high temperature melt method. The motivation is to investigate whether disruption of 1D Co2+ ferromagnetic chains by small Fe3+ substitution alters the antiferromagnetic ground state and lead to stronger spin-frustration. In this paper, we report the magnetic and magnetodielectric properties of Fe doped α-CoV2O6 in detail. The strongly anisotropic nature of magnetic and magnetodielectric characteristics were captured well in the data through orientation dependent measurements with H being parallel to a and c axes of the crystal. Relative dielectric permittivity (εr) exhibited sharp peaks coinciding with the plateau edges Hc1 ∼2.2 T and Hc2 ∼4.4 T in the magnetization curves (M-H) for applied H parallel to a-axis. For dielectric measurements under applied H parallel to c-axis, relative dielectric permittivity exhibited sharp peak around Hc2 ∼3.1 T, again coinciding with the M-H behavior. Such closely related magnetic field induced dielectric transitions reflected in both M(H) and εr(H) measurements is a rare phenomenon and representative of strong spin-lattice coupling in this phase.
      PubDate: Tue, 06 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000833
      Issue No: Vol. 14, No. 2 (2024)
       
  • High-frequency loss modeling of nanocrystalline core considering
           nonuniform distribution of flux density

    • First page: 025314
      Abstract: Nanocrystalline core is widely used in the design process of high-frequency transformers and inductors due to the attractive magnetic properties of nanocrystalline material. However, the flux density distribution is nonuniform in the core because the reluctance is closely related to its geometric shape. The nonuniformity of flux density distribution may cause huge calculation errors of core losses. In this paper, Finite Element Method (FEM) is used to justify taking into account nonuniform distribution of flux density during the process of core loss calculation. An improved loss separation equation considering nonuniform distribution of flux density is proposed, and the improved equation is verified through calculating and analyzing the losses of nanocrystalline cores with different wound thicknesses. Compared with the traditional loss separation equation, the accuracy is improved, and the average error of improved equation is confined in 10%.
      PubDate: Wed, 07 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000650
      Issue No: Vol. 14, No. 2 (2024)
       
  • Mesoscopic irreversible thermodynamics of aging kinetics of alpha
           polypeptides [DNA] under various constraints: Special reference to the
           simple spring mechanics

    • First page: 025315
      Abstract: The mesoscopic irreversible thermodynamic treatment of α-polypeptides and the helical polynucleotides (DNA) furnishes two sets of analytical expressions, which allow us not only to analyze the reversible force–extension experiments performed by atomic force microscopy (AFM) but also to predict the irreversible “aging” kinetics of the single-stranded and double-stranded polynucleotides (ssDNA and dsDNA) helical conformations exposed to aqueous solutions and applied static stress systems under the various constraints. The present physicochemical cage model emphasizes the fact that the global Helmholtz free energy of the helical conformation acts not only under the stored “intrinsic” unusual torsional and bending elastic energies inherited by the unfolded helical structure of the amino-acid (peptides) or the nucleic-acid (nucleotide) backbone but also reveals the importance of the interfacial Helmholtz free energy density associated with the interaction of the side-wall branches within the surrounding aqueous solutions. The analytical expression obtained for the unfolding force vs extension (FE) shows a strong non-linear elasticity behavior under the twist angle constraint when the interfacial Helmholtz energy term is incorporating into the scenario. This behavior is in excellent quantitative agreement with the AFM test results obtained by Idiris et al. (2000) on the poly-L-glutamic acid [Glu(n)-Cys] exposed to aqueous solutions, which show that acidity increases the degrees of helicity.
      PubDate: Wed, 07 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0183144
      Issue No: Vol. 14, No. 2 (2024)
       
  • Molecular dynamics study of thermal transport at interface between alumina
           and epoxy resin

    • First page: 025316
      Abstract: The study investigates heat transfer within a composite consisting of epoxy resin and alumina filler using all-atom molecular dynamics simulations. Various models of epoxy resin–alumina filler interfaces were analyzed, both with and without silane coupling agents (SCAs), to assess thermal conductivity and resistance. The results reveal that the presence of SCAs enhances heat transfer at the resin/filler interface. Conversely, models lacking SCAs exhibit a distinct temperature gap, indicating thermal resistance. In addition, the study suggests that effective heat transfer in polymer composites is influenced not only by molecular coupling at interfaces but also by the alignment of resin polymers.
      PubDate: Wed, 07 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189335
      Issue No: Vol. 14, No. 2 (2024)
       
  • Li-doping-modulated gelatin electrolyte for biodegradable
           electric-double-layer synaptic transistors

    • First page: 025317
      Abstract: Recent advances in the fabrication of neuromorphic electronic devices using biomaterials have received increasing attention for their prospect in biologically compatible and “green” electronic devices. Here, we proposed a novel electric-double-layer (EDL) synaptic transistor gated with Li-doped natural gelatin membranes, demonstrating larger capacitance at low frequency and extremely strong electrostatic modulation behavior. Experimental results have shown that a concentration of 2 wt. % Li-doping can obtain better electrical performance of EDL synaptic transistor. Ion/Ioff of 4.86 × 105 and threshold voltage of 0.68 V were obtained. Meanwhile, some important synaptic functions such as excitatory postsynaptic current, paired-pulse facilitation, and high-pass filtering characteristic have been successfully implemented. As a result, it can be inferred that the proposed gelatin-based natural polymer EDL electrolyte has demonstrated potential applications in “green” neuromorphic platforms.
      PubDate: Thu, 08 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0187167
      Issue No: Vol. 14, No. 2 (2024)
       
  • Non-Bayesian and Bayesian estimation for Lomax distribution under randomly
           censored with application

    • First page: 025318
      Abstract: This paper centers on the examination of the Lomax distribution in the context of randomly censored data. Our primary objectives include deriving maximum likelihood estimators and constructing confidence intervals based on the Fisher information matrix for the unknown parameters in the context of randomly censored data. Furthermore, we develop Bayes estimators utilizing gamma priors, considering both squared error and general entropy loss functions. We also calculate Bayesian credible intervals for the parameters. To offer practical insights, we apply these methods to a real-world dataset subject to random censorship. Finally, for comparative purposes, we conduct a Monte Carlo simulation to assess the various estimation techniques introduced in this study.
      PubDate: Thu, 08 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0176326
      Issue No: Vol. 14, No. 2 (2024)
       
  • Volume optimization of high-speed surface-mounted permanent magnet
           synchronous motor based on sequential quadratic programming technique and
           analytical solution

    • First page: 025319
      Abstract: This study proposes an innovative approach that integrates the subdomain method with sequential quadratic programming (SQP) to optimize the volume of a high-speed surface-mounted permanent magnet synchronous motor in an air compressor operating at 110 000 rpm. Unlike conventional optimization tools that often rely on finite element analysis (FEA) software, by leveraging the subdomain method for electromagnetic modeling, we obtain an analytical solution that rapidly represents the behaviors of the motor. Subsequently, the SQP technique is applied to optimize the volume of the model while satisfying design constraints. The proposed model is verified by FEA simulation.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000705
      Issue No: Vol. 14, No. 2 (2024)
       
  • Thickness dependent structural, morphological, and magnetic properties of
           PLD grown CoFe thin film

    • First page: 025320
      Abstract: The objective of the present investigation is to optimize the thickness of Pulse Laser Deposition (PLD)-grown CoFe thin films to achieve minimal effective Gilbert damping (αeff) for potential spintronics applications. The effect of the thickness (5-30 nm) of CoFe ultra-thin films on the Si/SiO2 substrate on the structural, morphological and magnetic properties has been reported. The X-ray diffraction (XRD) peak at 44.5° shows the growth of CoFe along the (110) crystal plane. A nearly square M-H loop with high saturation magnetization (Ms) suggests good crystalline growth of CoFe film. A high coercive field (Hc) observed in the thinnest 5 nm film is due to defects such as dislocations and stacking faults that appear at very low thickness. These defects gradually decrease with an increase in CoFe film thickness, as evident from a decrease in the Hc and an increase in the Ms. The value of αeff is largest for the thinnest 5 nm film due to defects and magnetic inhomogeneities present at this thickness. The damping is reduced by approximately one-third for the 10 nm thin film in comparison to the 5 nm film, which signifies a good quality film with fewer disorders.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000809
      Issue No: Vol. 14, No. 2 (2024)
       
  • Temperature-dependent hysteresis model based on temporal convolutional
           network

    • First page: 025321
      Abstract: The variation of temperature modifies the magnetic behavior of ferromagnetic cores which may affect the performance of electrical equipment. Therefore, it is imperative to develop a temperature-dependent hysteresis model to precisely calculate electromagnetic characteristics of electrical equipment. In this paper, a Temporal Convolutional Network (TCN) in combination with the Play operator is developed. The proposed model incorporates the temperature-dependent spontaneous magnetization intensity as the model input to introduce the temperature effect. To enhance the accuracy of model training outcomes, the Bayesian optimization approach for automatically selecting network model parameters is provided. The results show that the proposed model can accurately predict the hysteresis characteristics of materials under varying temperature and frequency conditions.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000824
      Issue No: Vol. 14, No. 2 (2024)
       
  • Mechanical C–C, C–O, and O–O bond formation between methanol
           molecules by laser-driven shock wave

    • First page: 025322
      Abstract: In this paper, all molecules (1,2-ethanediol, ethanol, methoxymethanol, dimethyl ether, and dimethyl peroxide) predicted to be produced as a result of C–C, C–O, or O–O bond formation between methanol molecules induced by laser-driven shock wave were detected and identified by gas chromatography-mass spectroscopy. In this process, the ultrahigh pressure resulting from the shock wave is considered to reduce the interatomic distance between molecules to mechanically create a new chemical bond. Methoxymethanol production was further verified by infrared absorption spectroscopy of the laser-irradiated methanol concentrated by vacuum distillation. In the concentrated sample, polyoxymethylene hemiformals, which are presumably produced by the polymerization of methoxymethanol, were also found.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0185586
      Issue No: Vol. 14, No. 2 (2024)
       
  • Scattering characteristics of silicon nanoprisms: A theoretical
           investigation across monomeric to hexameric structures

    • First page: 025323
      Abstract: Dielectric nanostructures exhibit intriguing optical properties and outstanding advantages in designing optical nanoantennas and metasurfaces compared to plasmonic nanostructures. This study employs classical electrodynamic methods to comprehensively explore the scattering characteristics of silicon triangular nanoprisms in monomer and oligomer forms. For monomeric nanoprisms, the scattering spectra reveal two distinct and prominent resonance peaks attributed to magnetic dipole (MD) and electric dipole (ED) modes. Reducing interparticle gaps within dimeric structures leads to noticeable blueshifts in MD resonance peaks with stable intensities, in contrast to the nearly constant position and significantly reduced intensities of the ED resonance peaks. A pronounced Fano-like resonance was observed upon transitioning to tetrameric and hexameric configurations, resulting from the coupling between MD and ED modes. A broad resonance peak also emerges in the long-wavelength region due to MD-to-MD coupling. The simulations conducted herein hold significant theoretical implications, advancing our comprehension of the scattering properties of dielectric nanoparticles and contributing valuable insights into fundamental nanophotonics.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0191112
      Issue No: Vol. 14, No. 2 (2024)
       
  • Effect of head on the flow state of water in tailwater channel of the
           hydropower station

    • First page: 025324
      Abstract: Hydropower station tailwater channel is often prone to elevated water levels and insufficient energy consumption, which leads to the influence of the output of the unit. To study the intrinsic connection between the water flow state and elevated water level in the tailwater channel, this paper investigates the water flow characteristics inside the tailwater channel of the Mupo Hydropower Station under different heads and verifies the accuracy of numerical calculations by constructing a physical model test platform. The results show that the maximum velocity at the bottom of the fluid domain near the anti-slope section of the tailwater channel decreases with the increase of head, while the velocity at the top of the fluid domain near the anti-slope section of the tailwater channel does not change much with the increase of head; a large vortex is formed in the middle of the upper part of the fluid domain in the anti-slope section of the tailwater channel; and the lower the head, the more obvious the vortex is. The results provide guidance for the design of tailwater channels at hydropower stations.
      PubDate: Fri, 09 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0187115
      Issue No: Vol. 14, No. 2 (2024)
       
  • Optimizing transcranial magnetic stimulator coils for minimal influence of
           individual variability in head geometry

    • First page: 025325
      Abstract: In prior studies focused on transcranial magnetic stimulator (TMS) coils, optimization of coil windings typically occurred on generic curved surfaces, such as planes or cylindrical shapes. However, these surfaces do not consider the challenge of coil misalignment, which arises due to variations in individual head geometries. This misalignment can significantly diminish the coil's effectiveness. To address this issue, we propose a novel coil design approach that identifies the 'best-fit' curved surface, minimizing the likelihood of mismatch with diverse skull geometries. We further enhance the coil winding pattern using the stream function applied to this custom curved surface. Numerical simulations using a hemisphere brain model demonstrate that the coil designed on this 'best-fit' curved surface exhibits a remarkable 22% increase in efficiency and a 41% expansion in stimulation area compared to the conventional butterfly coil. These findings underscore the advantages of our method in crafting high-efficiency and wide-ranging therapeutic TMS coil.
      PubDate: Tue, 13 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000795
      Issue No: Vol. 14, No. 2 (2024)
       
  • Magneto-optic interferometric system: Exploring building blocks and
           subcircuits

    • First page: 025326
      Abstract: Recent developments in the standardization of magnetic field generators have been considered for optoelectronic industrial-scale applications. In this work, a strategy to incorporate all optical components that can be used to implement a broad range of functions for communications applications is presented. We propose a circuit design for a magneto-optic interferometric system based on building blocks and subcircuits consisting of an interferometer with magneto-optic phase shifters and a magnetic field generator. The paper shows the building blocks based on elementary 2 × 2 photonics coupling components. We demonstrate that such a design can be configured as a tunable system based on the phase shift experienced by the incoming signals from two input waveguides and their transitions.
      PubDate: Tue, 13 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000704
      Issue No: Vol. 14, No. 2 (2024)
       
  • Ultra-highly efficient SOT-writing in MTJs with strain-induced magnetic
           anisotropy

    • First page: 025327
      Abstract: In order to break through limits of conventional MRAMs, MTJs with strain-induced magnetic anisotropy were intensively tested as SOT-MRAM cells. Small critical switching-current of 10–25 μA and switching-voltage of about 0.055 V, and almost no retention energy dependence of them were predicted and confirmed by experiments. Finally, high write efficiency of 1750 kBT/V (4.1 kBT/μA) and high write-power efficiency of 100 [kBT/(μA·V)] were obtained.
      PubDate: Wed, 14 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000654
      Issue No: Vol. 14, No. 2 (2024)
       
  • Piezoelectricity of lead-free hybrid perovskite monolayer (ATHP) 2 XY 4 (X
           = Ge, Sn; Y = Cl, Br, I): Cross-scale calculation and simulation

    • First page: 025328
      Abstract: Two-dimensional (2D) piezoelectric material is the core part of all kinds of micro-piezoelectric devices (piezoelectric energy harvesters, piezoelectric sensors, etc.). Based on the first principle, this paper theoretically predicts a kind of organic–inorganic lead-free hybrid perovskite monolayer (ATHP)2XY4 (X = Ge, Sn; Y = Cl, Br, I) with a large out-of-plane piezoelectric coefficient (d31). Combined with the finite element simulation, it shows excellent performance in the piezoelectric energy harvester. Through the first-principles theoretical calculation, the density, elastic tensor, piezoelectric stress tensor, and dielectric coefficient of the (ATHP)2XY4 monolayer can be obtained. The thermodynamic stability and mechanical stability of the materials are judged by ab initio molecular dynamics and stress–strain relationship analysis, respectively. The piezoelectric coefficient of the material is calculated, in which the d31 of (ATHP)2SnBr4 is the largest (d31 = 35.04 pm/V), which is still 7 times that of the bulk AlN and at least one order of magnitude larger than that of other 2D materials. The finite element simulation results of a simple piezoelectric beam show that the voltage output of the piezoelectric beam reaches 27.79 V. Our research shows that lead-free hybrid perovskite monolayer (ATHP)2XY4 has strong competitiveness in the application of environment-friendly and bio-friendly micro-piezoelectric devices. In addition, the cross-scale simulation method from the first principles to the finite element method is of great significance for the optimization of micro-piezoelectric devices.
      PubDate: Wed, 14 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0190029
      Issue No: Vol. 14, No. 2 (2024)
       
  • Electron acoustic counterpropagating multi-solitons and rogue waves
           collision in an unmagnetized plasma in the presence of critical density
           ratios

    • First page: 025329
      Abstract: In this paper, the nonlinear propagation of electrostatic collisional among multi-solitons around the critical values along with their corresponding phase shifts and collision between two rouge waves propagating toward each other is studied in an unmagnetized plasma environment. Using the concept of Hirota’s bilinear method, the useful forms of multi-solitons solutions of the coupled modified Korteweg–de Vries equations (mKdVEs) are determined. Furthermore, the coupled nonlinear Schrödinger equations (NLSEs) are derived from mKdVEs using the appropriate starching coordinates. The analytic solutions of different orders for the coupled NLSEs are also presented. The effects of the parameters related to the plasma environment on the electron acoustic scattered solitons, phase shifts and scattered rouge waves are analyzed. The proposed results provide the theoretical guidance to understand the propagation characteristics of collisional solitons, and their phase shifts around the critical values and collisional rouge waves in the modulated ranges.
      PubDate: Wed, 14 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0191067
      Issue No: Vol. 14, No. 2 (2024)
       
  • Research on target damage evaluation and optimization algorithm based on
           random incomplete information

    • First page: 025330
      Abstract: Timely and accurate assessment of battlefield strikes can improve the utilization of firepower resources and achieve optimal combat effectiveness. However, due to the complexity and uncertainty of the environment in actual war, it is difficult to obtain accurate target damage information, which can be expressed as uncertain, incomplete, or fuzzy decision information in mathematics. In this paper, the stochastic multi-criteria acceptability analysis method is used to evaluate the damage level of the target under an uncertain environment. We establish a set of characteristic indicators for the target damage effect and use the tracking results of maneuvering targets to determine the degree of target damage. Aiming at the uncertainty of the target data, the upper and lower limit dataset of uncertainty is established, and the membership function of the damage characteristic index is given. Combined with the probability density function, the comprehensive membership function of the damage effect is given, the acceptability index of each damage grade is compared, and the damage effect evaluation with uncertain weight information is given. Based on target vulnerability characteristics and combined with multiple damage elements, a target damage assessment model with multiple damage parameters is established, and the damage results are fitted. We study the relationship between target damage efficiency and various damage parameters. For the optimization strike problem of maximum damage to targets with multiple random incomplete information, a maximum damage optimization model is established using the objective function of maximizing damage probability and the missile firepower coverage area as constraint conditions. Experimental results show that the algorithm used in this paper can effectively solve the damage assessment problem under the condition of random incomplete information.
      PubDate: Wed, 14 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0194318
      Issue No: Vol. 14, No. 2 (2024)
       
  • A fabrication process of soft magnetic Ni films electroplated from gel
           electrolyte

    • First page: 025331
      Abstract: We have already reported some electroplated magnetic films using aqueous solutions. In the present study, we proposed a fabrication process for electroplated soft magnetic films (Ni films) using gel electrolytes. We added gelatin to the plating baths and confirmed that adding 22 g/L of gelatin enabled us to obtain gel electrolytes. Using the gel electrolytes, we electroplated Ni films and evaluated their structural and magnetic properties. From the evaluation of magnetic properties, we confirmed spontaneous magnetization of the Ni films prepared from the gel electrolyte. For obtaining thick Ni films (>1 μm), we investigated stirring the gel electrolyte during plating. As a result, we found that stirring increased the thickness, and our result suggests that stirring the gel electrolyte is useful to increase the deposition rate. In our experimental conditions, the deposition rate of the plating process was ∼0.25 μm/min. From XRD analysis, the structure of Ni films for gel electrolytes was oriented in the fcc (220) plane and slightly different from that for liquid electrolytes. From these results, we found that soft magnetic films could be obtained from the gel electrolyte and that gel plating is one of the attractive fabrication processes of the thick films.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000777
      Issue No: Vol. 14, No. 2 (2024)
       
  • Demagnetization analysis of outer-rotor-type BLDC motors considering
           permanent magnet overhang structure

    • First page: 025332
      Abstract: This paper presents an analysis of demagnetization of an outer rotor type brushless DC (BLDC) motor with a permanent magnet (PM) overhang structure. The proposed model converts the operating points of PM to consider such a three-dimensional (3D) structure in two dimensions (2D). In addition, the rotor yoke thickness of the proposed model is increased to consider the housing rotor. Ferrite PMs require demagnetization analysis owing to their decreasing coercivity at lower temperatures compared with rare-earth PMs. Hence, demagnetization analysis is conducted using a proposed model while considering, the PM overhang structure. The demagnetization analysis results are compared with the results of proposed model and 3D FEA analyses.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000732
      Issue No: Vol. 14, No. 2 (2024)
       
  • An efficient quantum circuit implementation of Shor’s algorithm for
           GPU accelerated simulation

    • First page: 025333
      Abstract: In this study, we introduce a novel implementation of Shor’s algorithm specifically designed for the Graphics Processing Unit (GPU) acceleration framework. Our focus lies on achieving efficient execution of the modular multiplication circuit through GPU simulation. To seamlessly integrate our design into the PyQPanda library framework, we made necessary modifications, making a deliberate trade-off by sacrificing a small number of quantum resources to leverage the advantages of GPU acceleration. Subsequently, we conducted simulations and rigorously validated the functionality of our circuit using the PyQPanda library, resulting in a significant speedup compared to a central processing unit-only mode.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0186385
      Issue No: Vol. 14, No. 2 (2024)
       
  • A fractional integral method inverse distance weight-based for denoising
           depth images

    • First page: 025334
      Abstract: Denoising algorithms for obtaining the effective data of depth images affected by random noise mainly focus on the processing of gray images. These algorithms are not distinct from traditional image-processing methods, and there is no way to evaluate the effectiveness of denoising after the point cloud transformation of denoised depth images. In this paper, the principle of fractional-order integral denoising is studied in detail and inverse distance weighted interpolation is introduced into a denoising model, which is based on the G–L (Grünwald–Letnikov) fractional-order integral to construct a fractional-order integral with an inverse distance weighted denoising model. The model is used to solve the blurring problem caused by sharp changes at the edge and achieves an excellent denoising effect. By using the optimized fractional-order integral denoising operator to construct a denoising model for depth images, the results of the experiments demonstrate that the fractional-order integral of the best denoising effect achieved by the model is −0.6 ≤ ν ≤ −0.4, and the peak signal-to-noise ratio is improved from +6 to +13 dB. In the same condition, median denoising has a distortion of −30 to −15 dB. The depth image that has been denoised is converted into an image of point clouds, and subjective evaluation indicates that the noise is effectively removed. On the whole, the results demonstrate that the fractional-order integral denoising operator with inverse distance weight shows the high efficiency and the outstanding effect in removing noise from depth images while maintaining the image related to the edge and texture information.
      PubDate: Thu, 15 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0185438
      Issue No: Vol. 14, No. 2 (2024)
       
  • Precise control of liquid–liquid interface position and geometry in
           open microchannels

    • First page: 025335
      Abstract: Accurate control of liquid–liquid interfaces is of great importance in many scientific fields. Currently, most studies on liquid–liquid interfaces are based on microfluidics in closed channels, and for open systems, it is difficult to form stable liquid–liquid interfaces in microchannels due to the interference of gas-phase molecules. Here, we introduce a new method to manipulate the motion of the liquid–liquid interface under an open microchannel. Under the effect of surface tension, the liquid–liquid interface moves in microchannels until it encounters microstructures in the microchannels, where the force equilibrates and remains stable to form a fixed shape. The shape of the interface is regulated by adjusting the dimensions of the microchannels and microstructures as well as the positions of the microstructures in the microchannels. This spontaneous liquid–liquid interface moves, stops, and remains stable in a very convenient way. The morphology and position of the interface are well manipulated using microstructures, and the liquid–liquid interface with well-defined geometry can be made to stay in different positions to play different roles.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189985
      Issue No: Vol. 14, No. 2 (2024)
       
  • Electrospinning preparation and characterization testing analysis of
           nanofiber biofilms

    • First page: 025336
      Abstract: In order to obtain a fibrous biofilm carrier material with a good water purification effect, the biofilm carrier of PAN and PAN-PEO (mass ratio 9:1) was prepared by the electrospinning process, and the performance differences between the fabric biofilm carriers of PAN, PAN-PEO (mass ratio 9:1), and blank non-woven fabric, including the structure of biofilm carriers (surface morphology, specific surface area, and porosity), surface wettability (water contact angle and water absorbance) and membrane hanging ratio, were tested through various characterization methods. The experimental results show that the nanofiber membrane of PAN and PAN-PEO (mass ratio 9:1) prepared by the electrospinning process has a diameter of 75–375 nm, a specific surface area of 19.2 m2/g, and a porosity of 80%. The fiber diameter of non-woven fabric is in the micrometer range, with a specific surface area of 0.3659 m2/g and a porosity of 60%. This indicates that the nanofiber biofilm of PAN and PAN-PEO (mass ratio 9:1) prepared by electrospinning belongs to the carrier with a small diameter, high specific surface area, and high porosity, which can provide more attachment sites and pores for micro-organisms and is more conducive to their attachment in wastewater treatment. At the same time, the water contact angles of PAN and PAN-PEO (mass ratio 9:1) are 27.97° and 18°, respectively, and the water absorption of both reached 300%. The water contact angle of non-woven fabric is 93.32°, and the water absorption rate is only 75%. This shows that the nanofiber biofilms of PAN and PAN-PEO (mass ratio 9:1) prepared by electrospinning effectively improve the infiltration of the carrier in sewage. Finally, under the same conditions, bacterial growth and biofilm growth experiments were conducted on the nanofiber biofilm carriers of PAN and PAN-PEO (mass ratio 9:1) and the biofilm carriers of non-woven fabric. It was found that the effectiveness of the PAN and PAN-PEO (mass ratio 9:1) nanofiber biofilm carrier was significantly higher than that of non-woven fabric in treating wastewater. After 3 days of bacterial cultivation, the membrane hanging ratio of the PAN nanofiber biofilm carrier was 90.36%, the membrane hanging ratio of the PAN-PEO (mass ratio 9:1) nanofiber biofilm carrier was 82.04%, and the membrane hanging ratio of the non-woven fabric biofilm carrier was only 27.32%. After 15 days of bacterial cultivation, the membrane hanging ratio of the PAN nanofiber biofilm carrier was 147.52%, the membrane hanging ratio of the PAN-PEO (mass ratio 9:1) nanofiber biofilm carrier was 147.52%, and the membrane hanging ratio of the non-woven fabric biofilm carrier was 110.53%.
      PubDate: Fri, 16 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0190239
      Issue No: Vol. 14, No. 2 (2024)
       
  • Drastic enhancement of stable and fast domain wall motion in GdFe
           nanowires through laser-annealing treatment at wire edges

    • First page: 025337
      Abstract: One of the key challenges in racetrack memory (RM) technology is achieving stable and high velocities for domain walls (DWs) while maintaining low power consumption. In our study, we propose a novel laser-annealing (LA) process to modify wire edges for a smoother DW movement along the nanowire. In this regard, a film stack of Pt (5 nm)/Gd26Fe74(20 nm)/SiN(10 nm) was deposited by magnetron sputtering. The DW velocity in the wire was measured by applying single voltage pulses and then observing the DW motion using a Kerr microscope. The current-induced domain walls motion measurements have shown that the LA process significantly enhances the velocity of DW motion. The LA of both edges of the nanowire results in a threefold increase in DW velocity compared to non-LA conditions. Further experiments illustrated that the DW velocity remains stable for the laser-annealed condition across a wide range of applied currents, spanning from 3 × 1011 to 7 × 1011 A/m2. Additionally, our investigation into the magnetic characteristics of laser-annealed nanowire regions exhibited a notable reduction of Hc at the laser-annealed edges. This decrease in Hc indicates greater ease in manipulating the material’s magnetization, which is essential for efficient DW motion. Furthermore, we explored the influence of LA on the Dzyaloshinskii–Moriya Interaction (DMI) field. The DMI finding underscores the strong correlation between DMI fields and DW speed. This achievement, i.e. the stability and consistency of the domain’s velocity (as the components of an RM) in a wide range of applied current, is significant progress in the field of operation and industrialization of RM.
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/9.0000747
      Issue No: Vol. 14, No. 2 (2024)
       
  • A fast closed-form approximate iterative fitting algorithm based on laser
           absorption spectrum

    • First page: 025338
      Abstract: This paper presents a novel approach—an efficient closed-form approximation iterative fitting algorithm based on laser absorption spectra. Through this closed-form approximation iterative fitting, key parameters such as peak value, spectral line width, and normalized signal area serve as indicators for iteration completion, improving the speed without compromising accuracy. Furthermore, it employs the spectral signal of n cycles as a window for further processing, minimizing external interference. The results show that the proposed method averages 9.75 iterations, while the Levenberg–Marquardt fitting method averages 60.17 iterations. The average iteration time for the proposed method is 588.83 ms, a substantial 81.7% reduction compared to the 3210.5 ms required by the Levenberg–Marquardt fitting. These results decisively demonstrate the efficacy of the proposed method in reducing iteration time and enhancing measurement precision.
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189657
      Issue No: Vol. 14, No. 2 (2024)
       
  • Improving the longitudinal spot width of an optimizingly designed
           point-like scatterer-arrayed transcranial ultrasonic lens

    • First page: 025339
      Abstract: As a non-invasive therapy to promote the effect of the thrombolytic agent in the acute phase of cerebral infarction, transcranial irradiation by ultrasonic waves at the site of the occlusion has been validated and is expected to achieve clinical application. Such irradiation may, however, cause damage to the brain by interference of reflected waves within the skull. In order to avoid such a phenomenon, we proposed a transcranial acoustic lens formed by optimizing the arrangement of point-like scatterers. The optimum arrangement of scatterers was determined so that the sound field vanishes within the skull except at the focus(es) and becomes higher at the focus(es) than in the surrounding regions. The ultrasonic waves are strongly scattered by air bubbles in the water-like medium, so we attempted to install a crossbar switch in the medium covering the head and constructed an acoustic lens by producing an instantaneously adaptive air bubble array. This lens can focus an incident plane wave to the diffraction limit in the direction perpendicular to the incident direction, while the peak width in the propagation direction is more than five times higher. In this work, in order to practically improve it, we propose to arrange a point-like scatterer so as to partially cover the head and further increase the number of layers. The shape of the skull is modeled based on CT data, and more realistic parameters are employed than in a previous paper [T. Ueta, J. Appl. Phys. 132, 144504 (2022)].
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0180275
      Issue No: Vol. 14, No. 2 (2024)
       
  • The stabilizing effect of collision on sheet instability in laser
           radiation pressure-based ion acceleration: A theoretical and simulation
           analysis

    • First page: 025340
      Abstract: In the past decade, transverse instabilities in the ion acceleration process using the laser radiation pressure method have been a prominent topic of discussion. These instabilities caused by the coupling between quasi-static ions with oscillating electrons through the ponderomotive force lead to the creation of density ripples in the target, ultimately resulting in the breaking of the target. This article investigates the collisional effects on the instability characteristic through theoretical and two-dimensional PIC simulation analysis. In agreement with our simulation studies, theoretical results show that the collision term enhanced the ion acceleration by decreasing the ion density accumulation and temporal growth rate of instability.
      PubDate: Wed, 21 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0189332
      Issue No: Vol. 14, No. 2 (2024)
       
  • Optimization of the double-slot blown airfoil with jet at the leading and
           trailing edges of the flap

    • First page: 025341
      Abstract: An active lift augmentation technique combining trailing edge blowing and blown flap is explored in this study. A double-slot blown flap airfoil is designed based on NACA23015. By optimizing the configuration parameters via the neural network surrogate model and particle swarm optimization algorithm, the lift coefficient at the 8° angle of attack reaches ∼5.14, which is approximately a 24% increasement relative to the baseline single-slot blown flap airfoil. In the configuration optimization, a longer flap facilitates lower pressure on the upper airfoil surface. Additionally, the aerodynamic flap effect caused by the double-slot jet flow intensifies the lift peaks and the pressure decreases over the airfoil. Ultimately, redistributing the jet momentum to the two slots achieves a highly efficient blown flap airfoil design.
      PubDate: Wed, 21 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0196505
      Issue No: Vol. 14, No. 2 (2024)
       
  • Some statistical properties of aeolian saltation

    • First page: 025342
      Abstract: Aeolian sediment transport is a process that commonly occurs on celestial bodies with atmospheric layers and solid surfaces. At present, it is very difficult to predict the instantaneous mass flux accurately. For the purpose of statistical prediction, the near-surface saltating grain count and the wind velocity above the saltation layer are synchronously measured in two dune fields. The duration and intensity of the saltation event obey exponential distribution, whereas sand transportation via saltation events with a smaller probability for a longer duration is significant. It is found for the first time that the Hilbert marginal energy spectrum of mass flux density follows the “−1” power law in a wide frequency range. In addition, the timescales of the energy-containing mass flux density mode and the strong wind–sand interaction of fluctuations are determined.
      PubDate: Wed, 21 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0192219
      Issue No: Vol. 14, No. 2 (2024)
       
  • Physical model-based ArF photoresist formulation development

    • First page: 025343
      Abstract: Since the logic 28 nm technology and beyond, ArF immersion lithography has been widely used in manufacturing. To fully utilize the potential of the lithographic resolution, process simulation has been used since the lithography process setup step. The accuracy of the model prediction can be a key factor in the process stability, defectivity, and yield of the final product. To get better model prediction, it is very important to develop a process model with as many parameters as possible with physical meanings. Since the analysis of exposure data with a physical model can provide insights into the process and the photoresist material, it may greatly accelerate the photoresist formulation development or improvement process. From another aspect, as the function of the photoresist is to record the aerial image information on wafer, theoretically, the photoresist image should not deviate much from the aerial image or it will inevitably reduce the information content of the aerial image, i.e., through various kinds of averaging, mixing, etc. Since the emergence of Optical Proximity Correction (OPC), the time that takes to finalize a photolithography process has been significantly lengthened and made more complicated. To make the OPC model more reliable and less dependent on patches, a more physical OPC model is necessary. Therefore, it is clear that if we can develop a photoresist formulation to realize a more physical photoresist image, or a photoresist image closer to the aerial image, we can greatly improve the photolithography process performance and the time consumed for the process setup including OPC. In this paper, we focus on several physical model parameters for photoresist, especially the effective photoacid diffusion length and photo decomposable base parameters. We will show that these two parameters can provide a good description of photoresist imaging behavior, and the resist formulation can be improved to match the physical model prediction with more accuracy.
      PubDate: Thu, 22 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0186648
      Issue No: Vol. 14, No. 2 (2024)
       
  • Comparative analysis of selective area grown Ga- and N-polar InGaN/GaN
           nanowires for quantum emitters

    • First page: 025344
      Abstract: In this paper, we report the molecular beam epitaxy-grown InGaN-quantum disks embedded within selective area epitaxy of GaN nanowires with both Ga- and N-polarities. A detailed comparative analysis of these two types of nanostructures is also provided. Compared to Ga-polar nanowires, N-polar nanowires are found to exhibit a higher vertical growth rate, flatter top, and reduced lateral overgrowth. InGaN quantum disk-related optical emission is observed from nanowires with both polarities; however, the N-polar structures inherently emit at longer wavelengths due to higher indium incorporation. Considering that N-polar nanowires offer more compelling geometry control compared to Ga-polar ones, we focus on the theoretical analysis of only N-polar structures to realize high-performance quantum emitters. A single nanowire-level analysis was performed, and the effects of nanowire diameter, taper length, and angle on guided modes, light extraction, and far-field emission were investigated. These findings highlight the importance of tailoring nanowire geometry and eventually optimizing the growth processes of III-nitride nanostructures.
      PubDate: Thu, 22 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0181213
      Issue No: Vol. 14, No. 2 (2024)
       
  • Novel study of inertial forces on MHD peristaltically driven micropolar
           fluid through porous-saturated asymmetric channel: Finite Galerkin
           approach

    • First page: 025345
      Abstract: This focused study investigates the peristaltic motion of a micropolar fluid within an uneven channel filled with a porous medium, incorporating an orthogonal magnetic field to the flow. This research diverges from the traditional assumptions of lubrication theory. The governing equations, encompassing the physical characteristics of micropolar fluid peristalsis, are transformed into nonlinear coupled partial differential equations. These equations are solved using the finite element method, considering inertial effects, such as non-zero wave and Reynolds numbers. This study delves into the influence of various crucial parameters on axial velocity, pressure gradient, microrotation, and stream function, presenting graphical representations. Notably, the incremental phase shift causes an intermingling of upper and lower streamlines within both halves of the channel. As the Reynolds number increases, there is an observed reduction in bolus size, particularly at maximum phase shifts, with a tendency to move toward the central region. An increase in Hartmann number leads the bolus formation to vanish in both channels, reduces microrotation, and leads to increased pressure. Vorticity lines intensify and incline toward the peristaltic walls. An increase in the permeability parameter amplifies velocity, microrotation, volume, and bolus formation regardless of phase differences while countering pressure elevation per wavelength. Reduced concavity is observed as vorticity lines disperse across the entire area.
      PubDate: Thu, 22 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0174973
      Issue No: Vol. 14, No. 2 (2024)
       
  • Dynamic characteristic analysis of the piston pump with the valve plate
           outer dead center damage

    • First page: 025346
      Abstract: The piston pump is one of the key components of the hydraulic system. The valve plate, one of the key friction pairs of piston pumps, contributes most to the dynamical stability and operational reliability of the pump. Existing research on the valve plate of the piston pump does not mention the outer dead center (ODC) damage, which is necessary when considering the dynamic characteristics of the piston pump facing failure. This paper establishes a flow area model and a fluid-domain simulation model of the valve plate of the piston pump under normal and damaged conditions. The dynamic characteristics in the pressure and vibration signals under ODC damage are analyzed. A piston pump testing with ODC damage is carried on to verify the proposed models. The simulation and the experimental signals are compared by extracting the fault features of the valve plate ODC damage.
      PubDate: Thu, 22 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0188659
      Issue No: Vol. 14, No. 2 (2024)
       
  • Investigation of terahertz radiation generation from laser-wakefield
           acceleration

    • First page: 025347
      Abstract: We investigate the generation of terahertz (THz) radiation from laser-wakefield acceleration (LWFA) in a helium gas jet. We consider a three-dimensional setup incorporating a realistic gas density distribution and use particle-in-cell simulations to study the interaction of a femtosecond intense laser pulse with the gas medium. Our results show that LWFA can efficiently produce THz radiation. In the simulations, we use multiple probes to record the electric and magnetic fields arising from the interaction. In addition, we compare the results of fixed and moving window simulation boxes used to capture electromagnetic fields in the THz range. We demonstrate that a moving window with a 600 μm width can be significantly useful for THz studies. We further analyze the spectrum of spatially and temporally resolved electromagnetic radiation and its emission angle. Our results are consistent with experimental data. Our findings provide valuable insights into the potential of LWFA as a strong source of THz radiation.
      PubDate: Fri, 23 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0187339
      Issue No: Vol. 14, No. 2 (2024)
       
  • Nanocomposite thin films containing Pt nanoparticles dispersed in an α-Fe
           2 O 3 matrix by RF sputtering

    • First page: 025348
      Abstract: The preparation of nanocomposite thin films that phase-separate Pt and α-Fe2O3 was investigated. These films were prepared on water-cooled glass substrates by radio frequency sputtering in an Ar atmosphere. X-ray diffraction patterns reveal that iron oxide forms Fe3O4 in the as-deposited state and undergoes a phase transition to α-Fe2O3 after heat treatment in the air. Pt is phase-separated from iron oxides in the as-deposited state and during heat treatment in the air, with a crystallite size of less than 2 nm in the as-deposited state, which varies between 2 and 15 nm after heat treatment in the air, estimated from the x-ray diffraction peaks. High-resolution transmission electron microscopy of the sample after heat treatment in the air reveals that spherical particles with a relatively uniform size are dispersed, which are assigned to Pt from fast Fourier transform analysis, while the surrounding area is assigned to α-Fe2O3. Thus, the thin film forms a nanocomposite thin film in which Pt nanoparticles are dispersed in α-Fe2O3.
      PubDate: Wed, 28 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0184320
      Issue No: Vol. 14, No. 2 (2024)
       
  • Electrical resistance switching of YbFe 2 O 4 single crystal bulk

    • First page: 025349
      Abstract: We report the electrical resistance switching of YbFe2O4, which is one of the electronic ferroelectrics and shows multi-step polarization reversal. The electrical resistance of the single crystal bulk of YbFe2O4 was measured along the c-axis. Three kinds of resistance states were observed: high resistance state (HRS), low resistance state (LRS), and extra low resistance state (ELRS). The as-grown sample was in HRS. The resistance state switched from HRS to LRS under an electric field of ∼180 V/cm. HRS was reproduced under the same magnitude of the electric field in the opposite direction. The switching from LRS to ELRS was assisted by a current flow in the ab-plane, which is orthogonal to the measurement axis (c-axis). The switching from LRS to ELRS was observed under an electric field of ∼140 V/cm during the resistance measurement along the c-axis after a current flow in the ab-plane for a few seconds. The resistance ratio in HRS, LRS, and ELRS was ∼2:1.5:1, which is regarded as a large value considering that the sample size was sub-millimeter order. This multi-step resistive switching is likely due to the multi-step reversal of electric polarization, accompanied by a multi-step change in Schottky barrier height between the sample and electrodes. The currents in the ab-plane are considered to release some pinnings and assist in the polarization reversal.
      PubDate: Wed, 28 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0194423
      Issue No: Vol. 14, No. 2 (2024)
       
  • Erratum: “Acoustic error approximation due to Gouy phase in the sea”
           [AIP Adv. 13, 075310 (2023)]

    • First page: 029901
      Abstract: These corrections in our original article1 do not affect any conclusions.Replace the phrase leading to Eq. (1) (“However, scaling these values is difficult, and there are other more direct methods”) with “RSSP is the radius of curvature due to Snell’s law, based on the wavespeeds (SSPs).”Equation (1): For the two-column format, please remove the “×” that makes the algorithm (second row) incorrectly appear to be a product (using “×”) with the first row of Eq. (1). Explanation: This second row uses the first by averaging the exponents “b” as in E[b], separately; it is not a product of the last term on the first row. This second row makes a threshold decision on that average E[b]. People familiar with logarithms would see the connection that the log(R−b) is proportional to −b. It could be appropriate to add “focus” as in “focus detected if” rather than just “detected if.” However, the final “focus found” result probably makes that clear.Add the phrase “without using Eq. (1)” to the sentence after Eq. (1) that starts “Ocean SSPs….” This should now read “Ocean SSPs (Fig. 6) are similar enough to calculate the foci directly from the SSPs, as in Sec. IV, without using Eq. (1).”The second sentence of the subsection titled “II D. Alternate physics and analysis methods” beginning “A short summary of this reflective convergence serves to contrast our concentration…,” should read “A short summary of this reflective convergence serves to contrast against our concentration….”In the second paragraph of “Sec. II D. Alternate physics and analysis methods,” change SSP to plural to become “The use of example distributions of SSPs and other parameters….”In the last sentence of the second paragraph of “Sec. IV A. The SOFAR, a characteristic example,” change “but are more out-of-phase than a (theoretically) symmetrical focus would appear to be” so that it reads “… yet have more volume of superposition than a (theoretically) symmetrical focus.”Change the title of subsection “IV B. Constant SSP produces a single bounce metric for acoustic lenses” to “Constant-slope SSP produces a single bounce metric for acoustic lenses.”In the final paragraph of Sec. IV C, replace v0x with c0.Add “Eq. (1)” to the final sentence of the Conclusion section so that it reads “So far, use of BSFs (a complicated method not reported here) via Eq. (1) only discovered strong horizontal foci in the deep (the SOFAR).”
      PubDate: Tue, 20 Feb 2024 00:00:00 GMT
      DOI: 10.1063/5.0179793
      Issue No: Vol. 14, No. 2 (2024)
       
 
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Publisher: AIP   (Total: 28 journals)   [Sort alphabetically]

Showing 1 - 27 of 27 Journals sorted by number of followers
Physics Today     Hybrid Journal   (Followers: 77, SJR: 0.66, CiteScore: 1)
J. of Applied Physics     Hybrid Journal   (Followers: 69, SJR: 0.739, CiteScore: 2)
Physics of Fluids     Hybrid Journal   (Followers: 58, SJR: 1.19, CiteScore: 3)
Applied Physics Letters     Hybrid Journal   (Followers: 52, SJR: 1.382, CiteScore: 3)
J. of Chemical Physics     Hybrid Journal   (Followers: 37, SJR: 1.252, CiteScore: 2)
J. of Mathematical Physics     Hybrid Journal   (Followers: 26, SJR: 0.644, CiteScore: 1)
Review of Scientific Instruments     Hybrid Journal   (Followers: 21, SJR: 0.585, CiteScore: 1)
Applied Physics Reviews     Hybrid Journal   (Followers: 15, SJR: 4.156, CiteScore: 12)
J. of Laser Applications     Full-text available via subscription   (Followers: 14, SJR: 0.741, CiteScore: 2)
J. of Renewable and Sustainable Energy     Hybrid Journal   (Followers: 14, SJR: 0.44, CiteScore: 1)
Physics of Plasmas     Hybrid Journal   (Followers: 11, SJR: 0.576, CiteScore: 1)
Acoustics Today     Hybrid Journal   (Followers: 10)
APL Materials     Open Access   (Followers: 10, SJR: 1.63, CiteScore: 4)
AIP Advances     Open Access   (Followers: 7, SJR: 0.472, CiteScore: 1)
Biomicrofluidics     Open Access   (Followers: 6, SJR: 0.592, CiteScore: 2)
Low Temperature Physics     Hybrid Journal   (Followers: 6, SJR: 0.264, CiteScore: 1)
Structural Dynamics     Open Access   (Followers: 6, SJR: 1.625, CiteScore: 4)
Chaos : An Interdisciplinary J. of Nonlinear Science     Hybrid Journal   (Followers: 4, SJR: 0.716, CiteScore: 2)
J. of Physical and Chemical Reference Data     Hybrid Journal   (Followers: 3, SJR: 1.046, CiteScore: 3)
Virtual J. of Quantum Information     Hybrid Journal   (Followers: 3)
AIP Conference Proceedings     Full-text available via subscription   (Followers: 2)
Biointerphases     Open Access   (Followers: 1, SJR: 0.558, CiteScore: 2)
Chinese J. of Chemical Physics     Hybrid Journal   (Followers: 1, SJR: 0.24, CiteScore: 1)
Surface Science Spectra     Hybrid Journal   (Followers: 1, SJR: 0.416, CiteScore: 1)
APL Photonics     Open Access   (Followers: 1)
Scilight     Full-text available via subscription  
APL Bioengineering     Open Access  
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