Authors:Gaoyan Duan et al Abstract: Modern Physics Letters B, Volume 28, Issue 23, 10 September 2014.
In this paper, we show the simulation of a plasmonic band-pass filter which consists of two surface plasmon polaritons (SPPs) waveguides and a resonator in metal–insulator–metal (MIM) structure. The resonator is formed by two square rings and a patch between them. The patch is a tiny rectangle cavity in order to transfer the SPPs from one ring to the other. The finite element method (FEM) method is employed in simulation. The results show that the dual-ring resonator performs better than a single ring does. The 3 dB bandwidth near the peak wavelength λ = 1054 nm is merely 31.7 nm. The resonant wavelength can be shifted by changing the side length of the square ring. This narrow band-pass filter is easy to fabricate and has potential applications in future integrated optical circuits. PubDate: Wed, 10 Sep 2014 10:07:22 GMT

Authors:Wende Cheng Abstract: Modern Physics Letters B, Volume 28, Issue 23, 10 September 2014.
A novel model using support vector regression (SVR) combined with particle swarm optimization (PSO) was employed to construct mathematical model for prediction of the magnetic properties of the NdFeB magnets. The leave-one-out cross-validation (LOOCV) test results strongly supports that the generalization ability of SVR is high enough. Predicted results show that the mean absolute percentage error for magnetic remanence Br, coercivity Hcj and maximum magnetic energy product (BH)max are 0.53%, 3.90%, 1.73%, and the correlation coefficient (R2) is as high as 0.839, 0.967 and 0.940, respectively. This investigation suggests that the PSO-SVR is not only an effective and practical method to simulate the properties of NdFeB, but also a powerful tool to optimatize designing or controlling the experimental process. PubDate: Wed, 10 Sep 2014 10:07:20 GMT

Authors:Jing Li et al Abstract: Modern Physics Letters B, Volume 28, Issue 23, 10 September 2014.
Analysis is given to acoustic directional radiation tuned by rotating square rods in two-dimensional (2D) solid–fluid phononic crystals (PC). The contour line method is introduced which predicts how the acoustic waves propagate at different frequency. As a specific example, for the systems of steel rods with square cross-section in a water host, we employ this approach to the analysis of the directivity successfully. The directional radiation frequency of two lowest bands are studied in this paper. The results show that the directional radiation frequency can be turned in a wide range by rotating the square rods. While the directivity of acoustic propagation keeps unchanged when the acoustic directional radiation frequency is located in the same band. Moreover, PCs exhibit excellent characteristic of single radiation branch as a corner cut off in a finite structure. Our approach may supply a new way to tune the directional radiation frequency. PubDate: Wed, 10 Sep 2014 10:07:19 GMT

Authors:Geng-Hua Yu et al Abstract: Modern Physics Letters B, Volume 28, Issue 23, 10 September 2014.
Magic wavelengths for laser trapping of barium atoms in the optical lattices are investigated while considering the optical clock transition at 877 nm between the 6s21S0 state and 6s5d 1D2 state. Theoretical calculation shows that there are several magic wavelengths with the linearly polarized trapping laser. The trap depths of the optical lattice and the slope of light shift difference with different magic wavelengths are also discussed and analyzed. Some of these magic wavelengths are selected and recommended for the optical lattice trapping laser. PubDate: Wed, 10 Sep 2014 10:07:19 GMT

Authors:L. H. Wang et al Abstract: Modern Physics Letters B, Volume 28, Issue 23, 10 September 2014.
This study proposes a novel beam splitter system based on graded photonic crystals, wherein the GPCs are part of a circular PC. A self-collimating PC structure with a square lattice is added to improve transmissivity. The total transmissivity is increased by extending the defect of the self-collimating PC. This study presents a beam splitter system with low energy loss and the best total transmissivity of almost 90%. Furthermore, the relationship between the beam-splitting ratio and the light position is discovered, and the beam-splitting ratio may be changed discretionarily and expediently. Numerical results are obtained using finite-difference time domain and plane wave methods. The proposed structure has significant application potential in optical integration. PubDate: Wed, 10 Sep 2014 10:07:19 GMT

Authors:Yan Wu et al Abstract: Modern Physics Letters B, Volume 28, Issue 23, 10 September 2014.
Corresponding relation between the electron distributions and the harmonic minimum is established, by taking for example of the harmonic generation of the aligned CO2 molecules in the highest-occupied-molecular-orbital (HOMO). We show that, as the polarization of the driving laser field rotates from parallel to perpendicular to the molecular axis, the harmonic yield first increases then decreases, and the location of the minimum in the harmonic spectrum moves to the higher energy region. These variations are connected with the electron distributions in the molecular orbital (MO) along the laser polarization of the driving laser field. Hence, by varying the laser polarization to scan, one can extract the overall electron distributions of the MOs from the generated harmonics. PubDate: Wed, 10 Sep 2014 10:07:16 GMT

Authors:Wen-Qiang Tian et al Abstract: Modern Physics Letters B, Volume 28, Issue 23, 10 September 2014.
In this paper, different types of noises, the sensing-noise and the acting-noise, are brought into the extended adaptive Attractive/Repulsive (A/R) swarming models to explore the role of noise in swarming formations. The difference between these two extended A/R models consists in the way in which the noise is introduced. The sensing-noise is added to the inputs of the swarming system which results in the uncertainty of the sensed information for agents, and it affects the whole processes of the swarming system. The acting-noise is added to the outputs of the swarming system, which does not affect the information-sensing and decision-making processes of the system, but it directly affects the action of swarms. With numerical simulations and analyses, the results show that the convergence of the expected swarming formation and the cohesiveness of the swarms may be affected to various degrees and suffered from certain negative impact due to the interference of different noises. We conclude that both the convergence and the cohesiveness are much more sensitive to the sensing-noise, and the model with acting-noise will be robust compared with the model with sensing-noise. Meanwhile we point out that, in the model with the interference of sensing-noise, too strong noises will lead to erroneous judgments of A/R function for agents. The sensed neighbor distance may fall into the zone of attraction, the zone of repulsion, or it may even fall into the zone of Non-A/R area. The original definite A/R function which is determined by the definite neighbor distance will evolve into the indefinite A/R function which is determined by the indefinite sensed neighbor distance. Along with the increase of the probability of such misjudgments, the effect of the A/R model will be progressively weakened. However, such phenomenon does not exist in the A/R model with the interference of acting-noise, in which the strong acting-noise leads the agents move randomly and spread apart gradually. PubDate: Wed, 10 Sep 2014 10:07:08 GMT

Authors:Xin Huang et al Abstract: Modern Physics Letters B, Ahead of Print.
Magnetism and transport are two key functional ingredients in modern electronic devices. In oxide heterostructures, ferroelectricity can provide a new route to control these two properties via electrical operations, which is scientifically interesting and technologically important. In this brief review, we will introduce recent progresses on this fast developing research field. Several subtopics will be covered. First, the ferroelectric polarization tuning of interfacial magnetism will be introduced, which includes the tuning of magnetization, easy axis, magnetic phases, as well as exchange bias. Second, the ferroelectric polarization tuning of transverse and tunneling transport will be reviewed. PubDate: Fri, 05 Sep 2014 08:32:58 GMT