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An attempt has been made to examine the energetic properties of M center diffusion, excitons near M²⁺, M⁺, M, M^- and M^2- centers and adsorptivity of atomic H and He over defect free and defect containing surfaces of LiH using an ab initio embedded cluster method at the Hatrtree–Fock approximation and Moller–Plesset second order perturbation correction. The results confirm the following, (1) the calculated barriers to diffusion of M center in its lowest triplet excited state is always greater than those in its singlet ground state; (2) the triplet M center is not produced directly by optical processes, but, indirectly by thermal diffusion; (3) the exclusive dependence of exciton bands and the nonexclusive dependence of band gaps on the defect charge; (4) surface relaxation is not more important than bulk relaxation; (5) the M center changes the nature of H adsorption from physical adsorption to chemical adsorption; (6) bulk or surface M^2- changes the nature of LiH from an insulator to a semiconductor; (7) as M center is introduced, the HOMO and LUMO levels of the substrate shift to higher energies and band gaps become narrower. This change in the electronic structure makes charge transfer between adsorbate and substrate levels and spin pairing with atomic H more facile.

The paper deals with Gauss–Bonnet gravity in five dimension without a Cosmological Constant and the coupling parameter is taken to be negative. Cosmological solutions are obtained for both bulk and the brane. The matter in the brane is chosen in the form of perfect fluid with barotropic equation of state (except the one with Modified Chaplygin Gas, which is not solvable) and the solutions are consistent with the recent observations.

In this paper, the magnetic fields end-face effect of high temperature superconducting (HTS) bulk over a permanent magnetic guideway (PMG) is researched with 3D-modeling numerical method. The electromagnetic behavior of the bulk is simulated using finite element method (FEM). The framework is formulated by the magnetic field vector method (H-method). A superconducting levitation system composed of one rectangular HTS bulk and one infinite long PMG is successfully investigated using the proposed method. The simulation results show that for finite geometrical HTS bulk, even the applied magnetic field is only distributed in $x$–$y$ plane, the magnetic field component Hz which is along the $z$-axis can be observed interior the HTS bulk.

This paper presents an investigation on ac losses of superconducting bulk caused by various magnetic wave conditions with the help of finite element software of Comsol Multiphysics. Three different magnetic wave conditions are analyzed, which are standing magnetic field, rotated magnetic field and traveling magnetic field. The calculation ac loss result was compared with that from analytical formulas for type-II superconducting slab and cylinder. The influences of the strength of external magnetic field on the ac losses were investigated. Effects of a relatively stable trapped-field of superconducting bulk on ac losses in time-varying magnetic field are clarified. Effect of spatially inhomogeneous distribution of the external magnetic field on the ac loss is studied.

First-principle calculations have been performed to systematically investigate the electronic and magnetic properties of Mn/C-codoped GaN. The formation energy of five different configurations is studied and the ground state is demonstrated to be ferromagnetic ordering. The ferromagnetic stabilization is largely due to the strong p–d hybridization among Mn 3d, C 3d and N 2p states. Our calculations show that the GaN codoped with Mn and C has a stable FM ground state with a high Curie temperature. These results are positive to design the dilute magnetic semiconductors with codopants in spintronics applications.

Motivated by the operation of bulk terminal in the Pearl River Delta, we study a berth allocation problem (BAP) with 2 berths and overall quay length constraint. The quay length occupied by a vessel depends on its berthing directions. The feasible berthing direction changes in a tide cycle. The objective is to minimize the total service of all vessels. We develop a mixed integer programming (MIP) model for the problem. We also propose an efficient genetic algorithm to tackle the problem. Our computational experiments show that the mixed integral programming model can only be solved by CPLEX for small-size instances, the genetic algorithm obtains good approximation solutions for large-size instances.

We investigate the role of bulk and shear viscosity in the spatially homogeneous anisotropic spacetime, in particular, the Kantowski–Sachs (KS) spacetime. General conditions for the bouncing evolution of universe in anisotropic background have been obtained by using the derived propagation equations of expansion scalar, shear scalar and spatial 3-curvature. We show that the presence of shear viscosity in the model prohibits the energy density to attain its extremum in the bouncing model. We explore the qualitative behavior of KS cosmologies by formulating the Einstein’s field equations into a plane-autonomous system of equations by taking dimensionless equation of state. The stability of the system has been investigated by evaluating and analyzing the eigenvalues at the critical points. The stable solutions exist for the system composed of bulk and shear viscosity. The present analysis through dynamical system method illustrates that the universe does not exhibit synchronous bounce with perfect fluid and/or viscous fluids in the KS spacetime.