Potential function of Fe_xO-SiO₂-CaO-MgO-"NiO" nickel slag in a two-atom model is constructed with nonempirical parameters. Microstructure and physicochemical properties of nickel slag are explored with molecular dynamics simulation. It shows that the potential energy of Fe_xO-SiO₂-CaO-MgO-"NiO" nickel slag can be characterized well with BMH(Born-Mayer-Huggins) potential function. It is beneficial to diffusion as CaO content of nickel slag is 15 wt.%, at which the coordination number of Si⁴⁺-Si⁴⁺ and the polymerization degree of slag are the lowest. The binding capacity of Fe with O^2- become stronger as Fe element is converted from Fe²⁺ to Fe³⁺, which makes the slag difficult to diffuse. It makes the viscosity of nickel slag increases rapidly and the smelting conditions become deteriorate. Therefore, the ratio of Fe²⁺/Fe³⁺ should be controlled strictly during nickel flash smelting. The simulated viscosity is consistent with measured value. It shows that the potential function reflects physical and chemical properties of nickel slag well.

An HLLC-type approximate Riemann solver is proposed to simulate one-dimensional elastic-perfectly plastic flow with Wilkins model. This Riemann solver introduces plastic wave and has the same wave number with actual physics. The wave speed is determined by characteristic analysis of wave system. The algorithm is simple to implement and does not need iteration. In order to reduce wall heating error in the simulation for strong shock (or rarefaction), wall heating viscosity is designed to effectively suppress the non-physical wall heating phenomenon.

In cell-centered Godunov method,unphysical overheating problem exists in rarefaction flows.We develop a Godunov method with staggered Lagrangian discretization which is applicable to isentropic flows. Velocity and thermodynamic variables are defined in staggered discretization. The velocity averaging process in a cell is avoided,so that the kinetic energy dissipation due to the momentum averaging process is removed. In contrast to the traditional von Neumann staggered grid method, the face flux is provided by a node multidimensional Riemann solver. The difficulty in selecting multidimensional artificial viscosity is overcome. In order to reduce unphysical entropy production of multidimensional Riemann solver in rarefaction problems,we give a reasonable criterion of rarefaction appearance to satisfy the thermodynamic relation. Numerical results show that the method removes overheating problem in rarefaction problems, and retains the property of accurate shock capturing of the original Lagrangian Godunov method as well.

A class of shock wave solutions of Zakharov-Kuznetsov-Burgers (ZKB) equation is obtained with hyperbolic-function-expansion method. Dynamical stability property of shock waves under transverse perturbations is investigated. Firstly, we made linear stability analysis on shock waves. A finite difference scheme with high accuracy is presented to solve numerically the eigenvalue problem. It shows that the shock waves are linearly stable with positive dissipation, while they are linearly unstable with negative dissipation. Secondly, a finite difference scheme is constructed to make long-time nonlinear dynamical evolution of shock waves. The results show that shock waves of ZKB equation are dynamically stable in the case of positive dissipation.

Weighted Laguerre polynomials-finite difference time domain (WLP-FDTD) method is employed to analyze transient response of transmission line in high-speed interconnect circuit system. Based on telegraph equation in equivalent circuit networks model,current and voltage are computed with weighted Laguerre polynomials. According to orthogonality,stability condition is eliminated. Different from finite difference time domain method,WLP-FDTD method is unconditional stable,which separates time and space variables. It is fast in computing large number of dissection networks for a transmission line. It shows that WLP-FDTD method is more efficient than traditional FDTD in analysis of transmission line. At last,a program with GUI is developed.

By using independent component analysis,a suppression method for zero-order term is proposed in off-axis digital holography.At first,two different amplitude frames of holograms are captured by a CCD-camera to form an observation signal.Secondly,a twin-image and a zero-order term are separated by means of independent component analysis.Finally,a separated twinimage is subtracted remnants zero-order term,which eliminates the zero-order term effectively.Computer imitating experiments show that this method is better then actual phase-shift method on advantage and validity.

A zero-order term suppression method for digital holography with Hilbert-Huang transform is proposed.Two-dimensional hologram data are changed into one-dimensional data.The first order of intrinsic mode functions containing high frequency of hologram is obtained by Hilbert-Huang transform through empirical mode decomposition.The second order of intrinsic mode functions containing direct current component of hologram is obtained similarly.Experiments show that reconstructed image of the first order of intrinsic mode functions represents conjugate image with suppressed zero-order term,and the second order of intrinsic mode functions represent the zero-order term.The proposed method preserves effectively information of original complex-wave and shows advantage in computational speed since it decomposes empirical mode decomposition once and obtains suppressed zero-order term in space frequency field well.

Based on two-dimensional domain decomposition with small overlapping,we provide a method in which local lower and upper triangular incomplete factors are combined into an effective approximation for global incomplete lower and upper triangular factors of coefficient matrix.Parallelization method is applicable to any preconditioner of incomplete type. Parallel performance metric of two-dimensional parallel preconditioner is compared to that of one-dimensional ones.Experiments show that it is more efficient than additive Schwarz technique and two-dimensional decomposition is better than corresponding one-dimensional decomposition as more processors are used for parallel computation.

Based on one-dimensional domain decomposition with small overlapping, we approximate local lower and upper triangular incomplete factors and combine these factors into an effective approximation for global incomplete factorization preconditioner of coefficient matrix. Two implementations are considered. One is based on exchange of total boundary values of overlapped domain. The other is based on carefully arranged computation process to reduce communication of whole overlapped domain in one line of grid points. The parallelization method can be used to any incomplete factorization preconditioner. Experiments show that it is more efficient than widely-used additive Schwarz technique.

Considering potential configuration of a silicon nanocrystal based memory and the mixing effect of valence bands,we calculate direct tunneling time of electron and hole with sequential tunnel theory and in the Bardeen's transfer Hamiltonian formalism.The programming and retention times of a silicon nanocrystal based memory are calculated.Influences of structure and bias on the performance of device are discussed.It is shown that new devices are expected in order to improve the retention property of silicon nanocrystal based memories.

In a sparse linear system derived from two-dimensional three-temperature energy equations, the diagonal dominan varies greatly from row to row and so is the magnitude of the elements. We provide a new scaling method to improve the diagonal dominance. As ILUT is used to the derived linear system, it reserves the number of elements in each row and several relatively large elements related to the photon are dropped due to the large difference among elements. To improve the equality of the ILUT, we provide a new method named multiple row ILUT (MRILUT), in which multiple rows are computed before dropping. The provided methods are embedded into a preconditioned Krylov subspace method to solve the actual two-dimensional energy equations with three temperatures. The number of iteration at each time step and the total computation time are both greatly reduced.

The Collar grid method and the virtual grid method are jointly used in the embedding technique to solve the problem of finding the interpolating cells among the internal and external boundary points near the joint regions. With different boundary planes generated along different fixed surfaces, the Collar grid obtained using the hyperbolic partial differential equations can ensure to generate high-quality grids and to provide real interpolating cells for the boundary points on the joint regions. The main purpose of the virtual grid is to convert a solid wall boundary condition into an interface condition while no fluid flow computations are conducted within the virtual grid. The computational results of several configurations show that the currently developed embedding technique with Collar grid and virtual grid can effectively treat the geometrical configuration and can more accurately predict the flow over complex configurations with intersecting surfaces.

A preconditioner of incomplete factorization types and a modified version are provided for the 3-D problems with the help of local block decomposition of a block tridiagonal matrix recursively. Then the existence of both preconditioners is focused on. For the seven point matrix discreted from the 3-D Laplace operator with the seven point difference technique, the actual condition numbers are computed and the results show that for the non-modified preconditioner, the condition number is proportional to N^2／3, where N is the order of the matrix. For the modified version, the condition number is proportional to the cube root of the order of the matrix thereafter. Finally, highly efficient implementation is considered and several effective experiments are done for these preconditioners on personal computers with main frequency of 550MHz and memory of 256M.

Computation of three dimensional fluid interface instability with random perturbation is performed on a 8 CPU personal parallel computer system.The parallel computation platform is a message passage interface (MPI).A second order TVD scheme with Ghost method is applied with a fully parallel algorithm to the 3D Euler equations.Level Set function is used to track the motion of a fluid interface in an Eulerian framework.Buffer zone and data communication are discussed.The number of computation meshes is about 1 million.Bubble evolution with random perturbation in Rayleigh Taylor instability is obtained by numerical simulation.

With the development of massively parallel processing, it is necessary that the parallel applications would be capable of good scalability. It is described how to use the near optimal scalability analysis method with the two dimensional electromagnetic plasma parallel program using particle in cell method as an example. Having known the performance of small parallel systems, one can obtain the information about how many processors which the larger systems are running on can obtain the more"reasonable" performance when using the near optimal scalability analysis. A suit of practical scalability evaluation method is also proposed to find the reason why the practical scalability is bad, and help to optimize the application programs.

A parallel solver for circulant block tridiagonal systems on distributed memory multicomputers is developed.The algorithm is based on matrix block operations.The implementation of this algorithm invokes BLAS3 subroutines.The complexity of the algorithm is analyzed.A sufficient condition guaranteeing the processes not to break down is given.The numerical experiments on a distributed memory multicomputer YH3E show that this algorithm has a high parallel efficiency.

It uses a Level Set function to track the motion of a fluid interface in an Eulerian framework.In addition,the use of Ghost cells (actually Ghost nodes in the difference framework) can keep the density profile from smearing out,while still preserving the scheme robust 2-nd easy to program with and accuracy TVD scheme in spacial and two step Runge Kutta methods.In contrast, the references[6][7] allow the density profile smearing out.This method significantly improves the resolution at the contact discontinuity.

The inverse problem of elliptic partial differential equation in the permeability field is discussed,whose permeability coefficient is nearly uniform.By using Radon transform in computerized tomography technology,the solution to this problem could be found,and some numerical examples are presented.

The LSQ coupled states of l-shell are constructed by (U,D)L-LSQ scheme, where U(D) is the total orbital angular momentum of spin up(down) electrons, the LS and Q are the total orbital angular momentum, spin and quasispin respectively, the (U,D) L-LSQ is unitary transformation. The scalar operators which commute with the total orbital angular momentum, spin and quasispin operators, are constructed from 4 creation-annihilation operators, and the LSQ coupled states are further or complete classified by its eigenvalues. The complete classifications of coupled states for f- and g-shell are obtained, the primary results of complete classifications of coupled states for g-shell are listed.

A parallel algorithm (PAA algorithm) is presented for the solution of diagonally dominant periodic tridiagonal linear systems. Its computation complexity is O(8n) and its communication complexity is O(1). But now the computation and communication complexity of the best parallel algorithm are O(17n) and O (log P) respectively. The PAA algorithm is implemented on the SGI Indy workstation cluster. The results show that the speed up has been improved linearly and the paralleling efficiency reaches to 90%.

By using the formalism ofsecond quantization and irreducible tensor,quasispin angular momentum scalaroperator Z(K),where K=2,…,2j,is constructed from 4 creation-annihilation operators.Theeigenvalues of Z(K) have special ability for classification of coupled states,by angular momentum J and quasispin Q the complete classification can be done only for j≤7/2,but by eigenvalues of Z(K)the complete classification have be donefor j≤15/2.The methods for calculating the eigenvalues of Z(K)are discussed,and the complete classifications for j≤15/2 are presented.

The energy level、wavelength and Oscllatar strength for Highly ionized NiI-like ions 3p⁶3d⁹,3p⁵3d¹⁰ and 3p⁶3d⁸4p configurations are calculated by using Cowan's multiconfiguration selfconsistent field method together with the fitting formula proposed here.

Four different types of serial multigrid preconditioned conjugate gradient algorithms are applied to treat interface problems, and their numerical convergence rates are also compared with respect to interface types, interface degree and stepsize. Schwarz parallelism is used for algorithms, and discussion concerns the convergence rates with respect to the number of subdomains, and the benefits owing to Schwarz parallelism. Detailed performence results are also given.

Four numerical methods for calculating coefficients of fractional parentage(CFP) of nucleons are compared,and the results show that the method of complete space by neutron-proton couplied is much better than that of over complete space,the method of factorization by group chains is much better than that of non factorization,and there are great differences of calculating amonut between different methods.

Visualization In Scientific Computing (VISC) is a rapidly developing application of computer graphics. This paper introduces a Visualization System In Quantum Mechanics-VISQUM, and discusses some methods and techniques used in this system.

A bisection method is presented for solving the eigenvalue problem of symmetric band matrices.This method is especially suitable for the case where only a few eigenpairs are needed. Further more,a modified strategy is also presented.The main idea is that firstly using the bisection for some steps to obtain an approximate eigenvalue,then Rayleigh Quotient Iteration is applied to extract the eigenvalue to a predifined accuracy.

A two parameter numerical inverse method of differential equation with only one complementary condition is presented.According to this principle a simultaneous inverse algorithm of lithology parameter and seismic source function of one dimensional wave equation is given in detail.Theoretical analysis and numerical examples demonstrate the existence of solution,stability and accuracy of the method.The method provides a suitable way to solve the difficulty of unknown source function in practical seismic exploration.The numerical results show the feasibility of the algorithm.

In this paper,the energy level-wavelength and Oscllatar strength for Highly ionized NiⅠ-like ions 3d⁹4s,3d⁹4p and 3d⁹4d configurations are calculated by using multiconfiguration selfconsistent field method together with the fitting formula proposed here. The calculations have a good agreement with observations.