For finite-difference time-domain (FDTD) scheme in simulation of electromagnetic wave propagation in Cole-Cole dispersive media. Several improvements are made:(1) preserving a term with static ionic conductivity in Cole-Cole model, which is fit for real Cole-Cole media; (2) extending to three-dimensional (3-D) case; (3) selecting parameters of human breast tissues from experiment. Feasibility and validity of the scheme is preliminarily demonstrated by numerical examples. The modified scheme is propitious to wave propagation in general Cole-Cole dispersive media.

We investigate numerically sedimentation of a drop-shaped particle in an infinitely vertical channel with a LB-DF/FD method. In the method, Navier-Stokes equations are solved by lattice Bohzmann method and fluid-solid interactions are handled by fictitious domain scheme. This work focuses on effects of particle shape factor on friction coefficient and drag coefficient of drop-shaped particle in Reynolds numbers ranging from 10^-2 to 10². Comparison with results of a circular particle is presented. It shows that particle friction coefficient keeps constant as Reynolds number is below 1. It increases as Reynolds number increasing as Reynolds number is greater than 1. Furthermore, it shows that both friction coefficient and drag coefficient of a circular particle are smaller than those of a drop-shaped one as Reynolds number is below 30 while it is greater as Reynolds number is greater than 30. To clarify this issue a detail investigation of pressure distribution around particle is presented.

A fluid model including two-temperature electrons was constructed for a collisionless plasma sheath. Effects of two-temperature electrons on sheath of stationary plasma were simulated. It is found that as temperature of cold electron is lower or density of cold electron at sheath adge is smaller critical ion Mach number decreases, sheath width becomes narrow and ion energy flow deposited on wall reduces. In addition, it is discussed that sheath thickness and ion energy flow deposited on wall are affected by cold electron in different plasma species.

We study photocathode of linear induction accelerator.A photoemission model was implemented which takes into account details such as photocathode material and laser source.A relationship between photocathode and macro particle initial condition is established.We achieved this model in LIAPIC code.A photocathode injector model was set up to simulate photoemission.At last,the model is verified.Simulation results are concordant with experiment.

Mathematical model with full tensorial permeability and mixed boundaries is presented to simulate single phase flow in heterogeneous reservoirs.A finite element method based on variational principle is proposed to solve the model.Fluid flows in homogeneous and heterogeneous reservoirs are simulated.It demonstrates that the finite element method is reliable and precise in determining flow behavior in heterogeneous reservoirs.It provides an important theoretical basis for detailed reservoir numerical simulation.

In the framework of Keating model, the effects of the symmetric and asymmetric two-body and three-body interactions between surface and substrate atoms on the formation of asymmetric dimers of Si(001)2×1 surface are discussed.The symmetric interactions induce the symmetric dimers.The results show that formation of asymmetric dimers of Si(00l)2×1 surface is mainly affected by the asymmetric three-body interactions rather than the two-body interactions.

The positions of atoms untill fifth layers of the reconstructed Si(100)2×1 surface are studied by simplex method. In addition, the reconstractions of diamond and Ge(100)2×1 are also investigated.