A local discontinuous Petrov-Galerkin method is proposed for solving three types of partial differential equations with second, third and fourth order derivatives, respectively. They are Burgers type equations, KdV type equations and bi-harmonic type equations. The method extends discontinuous Petrov-Galerkin method for conservation laws by rewriting corresponding equations into a first order system and solving the system instead of the original equation. The method has a fourth order accuracy and maintains advantages of discontinuous Petrov-Galerkin method. Numerical simulations verify that the method reaches optimal convergence order and simulates well complex wave interaction such as soliton propagation and collision.

Meso-scale heavy rain numerical model was studied.Regional atmospheric model parallel program with high hierarchy and modularity was built based on parallel applications infrastructure.With simulation of typical weather event, correctness, improvement of parallel performance and high-resolution simulation are tested.The new parallel model kept well prediction performance of original model and improved parallel performance and extendibility.The model simulated better with higher resolution.

A unified discontinuous Galerkin finite element framework on unstructured grids is developed to simulate gas-liquid twophase flows.In the framework,interior penalty discontinuous Galerkin (IPDG) method is employed to discretize imcompressible Navier-Stokes equations,while Runge-Kutta discontinuous Galerkin (RKDG) method is used to solve Level Set equation.Lid-driven cavity flow is simulated to validate IPDG method.Numerical results of bubble rising indicate the approach can be used to complex twophase flows with low computational efforts and simple implement.Moreover,RKDG method can effectively track deformations of interface without reinitialization.

In an elastic mechanics model,a magnetoelectric composites constitutive equation was established. Longitudinal and transverse ME voltage coefficient formulas of double-layer and three-layer composited thin films of 2-2 type in non-ideal condition were deduced with ferroelectric and magnetic constitutive equation. Composite ME voltage coefficient of ferromagnetic phase material nickel ferrite (NFO) and ferroelectric phase material lead magnesium niobate-lead titanate (PMNT) are studied. Relations between ME voltage coefficient and PMNT volume fraction,interface coupling parameters,two phase volume ratio and total number of layers are analyzed. It shows that performance of two phase material,appropriate volume fraction,coupling coefficient and total layer number are key to ME voltage coefficient.

For parallel computation,two techniques are proposed to couple Fourier transform and fluid dynamics.One is muiti-physics coupled communication technique and the other is parallel Fourier transform.By comparing efficiency of the two techniques,it is shown that the muiti-physics coupled communication technique is better than calling parallel FFTW technique as the number of cores is relatively small,while calling parallel FFTW technique is better as the number of cores is over a thousand.Scalability is demonstrated with a parallel efficiency above 50% on 16 384 processors.Numerical simulation on laser filamentation is shown.

An FFT parallel solver is designed and implemented in JASMIN infrastructure to solve problems,such as computation scale restriction,great change of data structure,different communications among data structures,and arguments' diversity of FFTW functions as using FFTW directly.The solver encapsulates several distributed storages of data,different communications and 1D FFT computations with FFTW.It provides standard functions to users.With this solver FFT parallel computing is realized conveniently.It was used in numerical simulations of laser filament.Scalability was demonstrated with a parallel efficiency above 80% on 2048 processors.

Effects of SEU and SEB are simulated with 0.4μm diameter microbeam. SEU for drain region of MOSFET and CMOS SRAM are calculated. Collective charge depending on LET for specific device structure is calculated for different ions. LET and critical charge are provided. SEB for VDMOS is simulated and electric field, potential line, current, rate of impact ionization are given at different times along ion tracks. It is very important for heavy microbeam test physics models which have been set up.

The MEDICI software of two dimensional simulation of semiconductor device is briefly introduced.Its characteristics and use are described.With the help of MEDICI,effects of total dose for MOSFET and dose rate for pn junction are simulated.Their physical models are set up.A theory approach is provided for the research of ionization radiation effects.