The effect of magnetization pinning at corners on spin wave dynamics in a spin wave conduit of yttrium iron garnet is investigated by using micromagnetic simulation. The simulation results reveal that two-magnon scattering brought on by this magnetization pinning scatters spin waves in various directions, resulting in a more dispersed spin wave pattern in k space. The evolution patterns of spin waves suggest that spin waves modes resonate at different applied magnetic fields, and magnetization pinning-induced magnon scattering brings the resonance fields of spin wave modes closer together. In addition, this magnon scattering modifies the intensity of spin wave modes at resonance, by more than 40 percent, for example, though altering their relaxation rate. By lengthening spin wave conduits the effects of this magnetization pinning could be limited, which may improve the performance of spin wave conduits.

An iDdQ(q-1) MRT LB model with external force term is proposed with multi-scale expansion and inverse design method. It recovers to incompressible Navier-Stokes equation with external force term under low Mach number assumption. With simulations of Poiseuille flow, pulsatile flow in a three-dimensional square channel, and two-dimensional Taylor vortex flow in a square box, it is found that numerical results are in good agreement with analytical solutions. In addition, spatial accuracy of the model reaches second order, which verifies effectiveness of the model in simulating steady and unsteady incompressible flows driven by external forces.

The symplectic algorithm in the complex symplectic space is the algorithm that preserves the Wronskian.The Wronskian calculated by using the symplectic scheme keeps unchanged which is in good agreement with theoretical analyses after a long distance of computation.The numerical solutions of the one dimensional model of strong laser field are calculated by using the Wronskian preserving and symplectic scheme.

In regard to the necessity of the study of high energy cosmic ray extensive air showers,a new Monte Carlo software is made which can simulate the hadron component,electromagnetic component and Čerenkov component of extensive air showers.This simulating program aims not only at the physics analysis of the EAS experiment of Mountain Liang-wang,but also at offering some samples that can be commonly used by other EAS experiments.

A high order accurate finite difference scheme is proposed in light of the upwind compact method^[1].The flux vectors in Euler equations are approximated by using upwind compact difference.In order to prevent the nonphysical oscillations in the vicinity of the shock the group velocity control(GVC)method is used.The reason of oscillation production in numerical solutions is nonuniformity of group velocity of wave packets.GVC is for improvement of the shock resolution.The present scheme has third order accruracy in smooth regions.

Taking account of the influence of diffusion and consistency of particles,a computer simulating model is presented based on random successive nucleation growth(RSNG) model of one-dimensional aggregation growth.A series of patterns and their fractal dimensions under nearest-neighbor and next-nearest neighbor conditions have been obtained.

A numerical Program is described. It can display the transport process of ions and the correspond cascade process in solids. It includes principle, physical models, calculation procedure and the range used. A newest nuclear scattering cross-section is used in this program. The Cub-Spline interpolation method is also used in order to raise calculation speed and precision. Some calculation results are given such as the range distribution, energy deposition, radiation damage distribution in semi-infinite medium by included ions with different energy.

The program for computing atomic electric dipole radiative transition probability has been written in Coulomb gauge and length gauge by using the program source ready in original MCDF package, based on the general theory of relativistic radiative transition, It has considered configuration interaction and orbital relaxation effects in the transitions.

A Probability description of an empirical method (called method A in this paper) used in simulations of high energy multiple production processes in which not only single particle momentum distribution but also energy conservation can be satisfied is presented and mathematically deduced. The applicable condition of method A is discussed.