We choose a confined point-contact geometry as research model. Steady-state oscillations of magnetic vortex driven by a spin-polarized current are calculated with analytical calculations based on Thiele's equation. It indicates that magnetic vortex can maintain steady oscillations in a specific current range. Current density range depends on nanocontact dimensions and dot aspect ratios. Both orbital radius and frequency of steady oscillations increases with current density. Adjustable range of oscillation frequency decreases dramatically with increasing nanoeontaet size.

Numerical technique is developed to clean spurious magnetic field divergence ▽·B in full MHD (Magnetohydrodynamics) simulation.Eight-wave equations are solved in basic scheme combined with additional source term ▽·B to keep conservation.A projection scheme is used to clean spurious magnetic field divergence.3D Poisson equation is solved with a finite volume method.For smooth analytical field,▽·B is cleaned efficiently.While for hypersonic MHD blunt flows with shock wave,▽·B error increases sharply in free stream region.A local projection scheme is proposed to clean ▽·B in relatively high divergence region. Flow field converges well and magnetic field divergence in low divergence region is not influenced.

The time step in a molecular dynamic method is defined as a function of the largest acceleration,the largest velocity and the largest allowed space step of a particle.Using this algorithm,the lowest-energy geometries of smaller LJ clusters and H₂O clusters are obtained,and the efficiency of this algorithm is demonstrated.A lowest-energy structure of(H₂O)₁₃ is found.

Based on an initial structural mesh, a data structure for a 3-D body-fitted tree mesh was built. Simplified algorithms were developed for anisotropic self-adaptive split and mergence. In order to reduce the number of mesh cells we set restrictive self-adaptive levels for different zones divided in advance. A method of protective mesh split for structures in flow field was developed. Numerical simulations with different complex supersonic flow patterns were shown. It is proved that the anisotropic self-adaptive tree mesh is effective with less mesh cells and convenient for mesh refinement. High resolution for Now field is obtained.

The Monte Carlo method is used in the single event simulation which describes the processes of the particle transportation and the random sampling. Particularly, the single event upset of a silicon chip induced by 14*!MeV neutrons at a random incident angle is calculated and analyzed. In the mean time, the Monte Carlo error is also considered. By the Monte Carlo method, some information about the physical mechanism of the single event upset is provided.

A 13-speed lattice Boltzmann model is used to investigate Couette flow with a temperature gradient and viscous cavity flow. The Couette flow for Pr=0.91, Re=100,5000 and Pr=0.91,1,1.25 and Re=3000, are simulated with the evolution of driven flow, temperature and viscous heat dissipation. And the distributions of vortex and temperature are shown at Re=3000 the steady flow field for viscous cavity flow.

Based on physical mechanism of the interaction between incident neutrons and silicon atoms, a simulation program of Single Event Upset (SEU) induced by neutrons is compiled by Monte Carlo method. The process of SEU of a 16 K static access memory silicon chip induced by 14 MeV incident neutrons has been simulated by the program. The simulation results show that the program can provide a detailed description of the physical process of SEU of a silicon chip and can produce reference data about SEU cross section in a 14 MeV neutrons evironment.

The Single Event Upset (SEU) of a 16 K random access memory (RAM) silicon chip induced by a beam of incident neutrons with 10-20 MeV energies is simulated by a Monte Carlo method. The angle distributions and energy distributions of the proton and alpha particles from the reactions of (n,p) and (n,α) have been obtained with the average angles and average energies of these outing charged particles. For different critical charge of the 16 K RAM silicon chip and different ratio of width and length of sensitive volume, the calculated results cover the incident neutron flux which can induce one upset of these sensitive volume in the chip, and the cross section of SEU of the chip.

The oscillating solutions of the magnetic fields may arise on an axisymmetric model by using first order finite elements.In addtion,they may also occur for nonuniform grids.The paper analyses the cause of forming oscillating solutions and the behaviour of oscillating solutions.The methods of cancelling the oscillation are suggested.

Free-Lagrange Method is a new attempt to simulate two dimensional compressible flow with large distortion. It gives up the restraint usually required in traditional Lagrangian method to make fixed connectivity among cells. In FLM the neighbor relation among notes is tested and revised in each cycle, therefore adapti flow distortion naturally. In addition we have made special treatments for free surfaces and interfaces. The application of FLM to hydro-elastic-plastic flow proves to be satisfactory.

A phenomenological model of shock initiation and detonation of heterogeneous explosives is implemented in the one-dimensional hydrodynamic code based on the method of characteristics. Since there is no artificial viscous term to smear the shock, we can get a clear picture of the simulated structure of detonation wave. We have calculated Unsteady detonation process of PBX-9404 and the results are quite well consistent with the experiment data.