Authors:G. Subhashree, S. Sankar, R. Krithiga Abstract: Modern Physics Letters B, Volume 28, Issue 30, 10 December 2014. Self-consistent first principle calculations were carried out to investigate the structural, electronic, thermal and superconducting properties of Mo3X (X = Os, Ir, Pt) compounds of A15 phase that are studied by using the tight-binding linear muffin-tin orbital method. The E and k convergence have been checked to analyze the ground state properties. The band structure and DOS histograms are plotted from the calculated equilibrium lattice parameter. The bulk modulus (BB), Debye temperature (θD), density of states (N(EF)), electron–phonon coupling constant (λ), superconducting transition temperature (Tc) and electronic specific heat coefficient (γ) have been calculated from the electronic band structure results. The calculated values have been compared with the available experimental results of literature. Citation: Modern Physics Letters B PubDate: Thu, 11 Dec 2014 05:53:43 GMT DOI: 10.1142/S0217984914502339

Authors:Yuhong Zhang, Baoyuan Liu, Keqing Lu, Wangyun Liu, Jun Han Abstract: Modern Physics Letters B, Volume 28, Issue 30, 10 December 2014. We numerically simulate the evolution of the dark-notch-bearing optical beam in the logarithmically saturable nonlinear media based on beam propagation method (BPM). The simulation results indicate that the multiple dark spatial solitons are deep, possible in this type of nonlinear media. The number of multiple dark spatial solitons depends on the width of the dark notch, the initial conditions and the peak intensity of the initial input beam. Under the odd and even initial conditions, the odd and even number sequence of multiple dark spatial solitons can be obtained, respectively. For an input beam with fixed optical intensity, the number of dark solitons increases with the width of the initial input dark notch. The behavior of the multiple dark solitons in this type of media is similar to that in a photorefractive nonlinear crystal. Citation: Modern Physics Letters B PubDate: Thu, 11 Dec 2014 05:53:43 GMT DOI: 10.1142/S021798491450239X

Authors:Ann Junghans, Mary Jo Waltman, Hillary L. Smith, Luka Pocivavsek, Noureddine Zebda, Konstantin Birukov, Mariano Viapiano, Jaroslaw Majewski Abstract: Modern Physics Letters B, Volume 28, Issue 30, 10 December 2014. Neutron reflectometry (NR) was used to examine various live cells' adhesion to quartz substrates under different environmental conditions, including flow stress. To the best of our knowledge, these measurements represent the first successful visualization and quantization of the interface between live cells and a substrate with sub-nanometer resolution. In our first experiments, we examined live mouse fibroblast cells as opposed to past experiments using supported lipids, proteins, or peptide layers with no associated cells. We continued the NR studies of cell adhesion by investigating endothelial monolayers and glioblastoma cells under dynamic flow conditions. We demonstrated that neutron reflectometry is a powerful tool to study the strength of cellular layer adhesion in living tissues, which is a key factor in understanding the physiology of cell interactions and conditions leading to abnormal or disease circumstances. Continuative measurements, such as investigating changes in tumor cell — surface contact of various glioblastomas, could impact advancements in tumor treatments. In principle, this can help us to identify changes that correlate with tumor invasiveness. Pursuit of these studies can have significant medical impact on the understanding of complex biological problems and their effective treatment, e.g. for the development of targeted anti-invasive therapies. Citation: Modern Physics Letters B PubDate: Thu, 11 Dec 2014 05:53:42 GMT DOI: 10.1142/S0217984914300154

Authors:Qihui Ye, Chen Wang, Kai Guo, Wenzhi Chen Abstract: Modern Physics Letters B, Volume 28, Issue 30, 10 December 2014. An ultracompact wavelength demultiplexing structure based on the resonator-coupled effect is proposed and demonstrated numerically. The structure consists of a cross plasmonic-waveguide structure with baffles in the output channels, each of which functions as resonator. Due to the strong couplings of different resonators in the structure, a series of continuous sharp transmission spectra occur. This considerably increases the wavelength resolution of wavelength demultiplexing, which is obviously narrower than the full width of the isolated resonator. The proposed structure could be utilized to design of ultracompact wavelength-division multiplexing (WDM) systems for large-scale photonic integration. Citation: Modern Physics Letters B PubDate: Thu, 11 Dec 2014 05:53:42 GMT DOI: 10.1142/S0217984914502364

Authors:Subramanian Ramakrishnan, Thomas Laurent, Manish Kumar, Andrea L. Bertozzi Abstract: Modern Physics Letters B, Volume 28, Issue 30, 10 December 2014. In this paper, we present a generic theoretical chemotactic model that accounts for certain emergent behaviors observed in ant foraging. The model does not have many of the constraints and limitations of existing models for ants colony dynamics and takes into account the distinctly different behaviors exhibited in nature by ant foragers in search of food and food ferrying ants. Numerical simulations based on the model show trail formation in foraging ant colonies to be an emergent phenomenon and, in particular, replicate behavior observed in experiments involving the species P. megacephala. The results have broader implications for the study of randomness in chemotactic models. Potential applications include the developments of novel algorithms for stochastic search in engineered complex systems such as robotic swarms. Citation: Modern Physics Letters B PubDate: Thu, 11 Dec 2014 05:53:41 GMT DOI: 10.1142/S0217984914502388

Authors:Kwok Sau Fa Abstract: Modern Physics Letters B, Volume 28, Issue 30, 10 December 2014. The description of a particle in the quantum system is probabilistic. In the ordinary quantum mechanics the total probability of finding the particle is conserved, i.e. the probability is normalized for all the times. To find a non-constant total probability an imaginary term should be added to the potential energy which is not physical. Recently, generalizations of the ordinary Schrödinger equation have been proposed by using the Feynman path integral and analogy between the Schrödinger equation and diffusion equation. In this work, an integro-differential Schrödinger equation is proposed by using analogy between the Schrödinger equation and diffusion equation. The equation is obtained from the continuous time random walk model with diverging jump length variance and generic waiting time probability density. The equation generalizes the ordinary and fractional Schrödinger equations. One can show that the integro-differential Schrödinger equation can describe a non-constant total probability for a free particle, and it includes the exponential decay which is fundamental for the description of radioactive decay. Citation: Modern Physics Letters B PubDate: Thu, 11 Dec 2014 05:53:39 GMT DOI: 10.1142/S0217984914502340

Authors:F. Nasehnia, M. Seifi Abstract: Modern Physics Letters B, Volume 28, Issue 30, 10 December 2014. Adsorption of molecular oxygen with a triplet ground state on Fe-, Co-, Ni-, Ru-, Rh-, Pd-, OS-, Ir- and Pt-doped graphene is studied using density functional theory (DFT) calculations. The calculations show that O2 molecule is chemisorbed on the doped graphene sheets with large adsorption energies ranging from -0.653 eV to -1.851 eV and the adsorption process is irreversible. Mulliken atomic charge analysis of the structure shows that charge transfer from doped graphene sheets to O2 molecule. The amounts of transferred charge are between 0.375e- to 0.650e-, indicating a considerable change in the structures conductance. These results imply that the effect of O2 adsorption on transition metal-doped graphene structures can alter the possibility of using these materials as a toxic-gas (carbon monoxide, hydrogen fluoride, etc.) sensor. Citation: Modern Physics Letters B PubDate: Thu, 11 Dec 2014 05:53:39 GMT DOI: 10.1142/S0217984914502376

Authors:Yahong Xie, Wenwen Kong, Guang Ji, Bo Gao, Jincheng Yao, Aimin Chang Abstract: Modern Physics Letters B, Volume 28, Issue 30, 10 December 2014. Mn1.56Co0.96Ni0.48O4-δ thin films were deposited on MgO (100) substrate using laser molecular beam epitaxy (LMBE) technique at the temperature range of 300–600°C under oxygen partial pressure of 5 × 10-3 Pa. The effect of growth temperature on microstructure and electrical properties as well as the growth mode were studied using XRD, RHEED, AFM and resistance–temperature measurements. The results showed that all prepared thin films underwent epitaxial growth along the single-(100) orientation direction of the MgO substrate from 3D-island mode to 2D layer-by-layer mode, and exhibited good crystallinity and NTC thermistor behavior. Their resistance at room temperature can be in the range of 10–50 MΩ together with a B-value of about 3300 K, which are desirable for a wide range of practical applications of the NTC thermistors. Citation: Modern Physics Letters B PubDate: Thu, 11 Dec 2014 05:53:38 GMT DOI: 10.1142/S0217984914502352

Authors:Zhenyue Zhu, Steven R. White Abstract: Modern Physics Letters B, Ahead of Print. Searching for spin-liquid states has long been attracting both experimentalists and theorists. In this paper, we review recent density matrix renormalization group studies of the spin-½ XY model on the honeycomb lattice, with first-neighbor (J1 = 1) and frustrating second-neighbor (J2 > 0) interactions. For the intermediate frustration regime 0.22 ≲ J2 ≲ 0.36, there exists a surprising antiferromagnetic Ising phase, with ordered moments pointing along the z-axis, despite the absence of any SzSz interactions in the Hamiltonian. Surrounding this phase as a function of J2 are antiferromagnetic phases with the moments pointing in the xy-plane for small J2 and a close competition between an xy-plane magnetic collinear phase and a dimer phase for large values of J2. No spin-liquid phases was found in the XY model even with the third-neighbor (J3>0) interactions. Citation: Modern Physics Letters B PubDate: Fri, 12 Dec 2014 10:37:20 GMT DOI: 10.1142/S0217984914300166