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25 November 1998, Volume 15 Issue 6 Previous Issue    Next Issue

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REVIEW ON A TWO-DIMENSIONAL PARTICLE-SIMULATION PROGRAM OF LASER-PLASMA INTERACTION Liu Daqing, Cao Lihua, Chang Wenwei, Yue Zongwu 1998, 15(6): 641-647.  Abstract ( )   PDF (263KB) ( )   The distinguishing features of the two-dimensionl particle simulation program developed for research on laser-plasma interaction are described.

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THE NUMERICAL OPTIMIZATION COMPUTATION OF FLUID/ELECTROMAGNETIC FIELDS Zhu Ziqiang, Zubair Islam, Zhu Yikun, Xue Xiaochun 1998, 15(6): 648-653.  Abstract ( )   PDF (279KB) ( )   The vector flux splitting scheme is used to calculate the time domain electromagnetic scattered characteristics.Radar cross section(RCS) is then evaluated with equivalence principle and Fast Fourier Transformation.Van Leer's splitting scheme serves to solve the Euler equations to obtain the aerodynamic characteristics.Two obtained solutions are coupled with a simple effective numerical optimization algorithm.

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NUMERICAL SIMULATIONS OF THE COLLISIONS BETWEEN TWO SOLITARY WAVES AND THE TRANSFORMATION OF A SOLITARY WAVE OVER BACKWARD STEP BY VOF METHOD Wan Decheng 1998, 15(6): 654-666.  Abstract ( )   PDF (545KB) ( )   The full 2D Navier Stokes equations and VOF technique are adopted to solve numerically problems of the collisions between two interfacial solitary waves and of the transformation of a solitary wave passing over backward step.

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AN UPWIND FINITE ELEMENT SCHEME ON UNSTRUCTED GRIDS Cai Qingdong 1998, 15(6): 667-671.  Abstract ( )   PDF (257KB) ( )   Based on the modification to the integal domain, an upwind finite element scheme is presented. Just as the first order upwind difference scheme, which is its conterpart in finite difference methods, it applies to construct many numerical schemes on unstructed grids.

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FAST GENERATING TWO DIMENSIONAL NUMERICAL GRIDS LINE BY LINE Xu Tao, Shui Hongshou 1998, 15(6): 672-679.  Abstract ( )   PDF (548KB) ( )   Fast generating two dimensional numerical grids line by line is discussed. Grid generation method which uses parabolic partial differential equations for external region of bodies in References[1] is extended to enclosed region. The idea is also applied to solve more complex elleptic partial differential equations for grid generation. Some generated grids by the method are presented.

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THE AUTOMATIC AND SEMI-AUTOMATIC NUMERICAL INVERSION OF LAPLACE TRANSFORM METHOD BASED ON LAGUERREL POLYNOMIAL Feng Zhigang, Zhou Jianping 1998, 15(6): 680-686.  Abstract ( )   PDF (264KB) ( )   A new automatic and semi automatic numerical inversion of Laplace transform method based on Laguerre polynomial is presented.The optimum choice of transform parameters is introduced and the numerical results are also given.

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COMPUTER SIMULATION OF LIQUID SHEAR VISCOSITY Wang Wen, Liu Zhigang, Chen Zhongqi 1998, 15(6): 687-691.  Abstract ( )   PDF (186KB) ( )   This paper reviews the works about computer simulation of liquid shear viscosity.The Argon at triple point,considered as sphere molecule with Lennard-Jones potential energy,is numerically simulated with NEMD(non equilibrium Molecular dynamics)method.The results are consistent with those in references.

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CONSTRAINED GLOBAL OPTIMIZATION ALGORITHM FOR THE BEAM SHAPING OF UNIFORM ILLUMINATION Liu Li, Deng Xuegong, Li Yongping 1998, 15(6): 692-696.  Abstract ( )   PDF (203KB) ( )   The constrained global optimization(CGO) algorithm is used to optimally design one demension diffrative optical element(DOE).The adopted CGO method is described in detail.The results are also given.

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ELECTRON IMPACT IONIZATION NO-RELATIVISTIC TRANSITION MATRIX ELEMENT FOR H-LIKE IONS Jia Xiangfu, Yang Peilin, Shi Qicun, Xu Kezun 1998, 15(6): 697-703.  Abstract ( )   PDF (272KB) ( )   The non-relativistic transition T-matrix element for electron impact ionization of H-like has been calculated with starting from the formulation of Brauner,Briggs and Klar.The final state wavefunction involving three appropriate confluent hypergeometric functions considers all three two-body interactions on an equal footing and satisfies the proper Coulomb boundary conditions.The long range Coulomb interaction occurring in the initial channel has been taken into account properly.The T-matrix element,including four confluent hypergeometric functions,has been reduced to a three-dimensional integral in real space.The results are of use in a wide class of scattering problems.

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AN IMAGE RECONSTRUCTION ALGORITHM BASED ON VALUE CORELATION TECHNOLOGY IN ELECTRICAL IMPEDANCE TOMOGRAPHY Sun Jinping, Du Yan, Cheng Jikuan 1998, 15(6): 704-710.  Abstract ( )   PDF (260KB) ( )   On the basis of value corelation theory,a new image reconstruction algorithm is proposed for electrical impedance tomography.Theorical analysis and numrical results are also given.

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The Computation of 3-D Hypersonic Ionized Flows in Thermochemical Nonequilibrium Xie Zhongqiang, Ouyang Shuiwu 1998, 15(6): 711-716.  Abstract ( )   PDF (244KB) ( )   A numerical method for the computation of 3-D hypersonic ionized flows in thermochemical nonequilibrium has been developed. The thermodynamic state of real gas is modeled with a translational rotational temperature and an electron vibrational temperature. Numerical investigations are performed for 3-D hypersonic ionized flows around an axisymmetric blunt body and over blunt body at angle of attack. Real gas Navier Stokes computations relies on a finite volume approach based on an Implicit NND scheme. The agreement with other computations has been found to be good. The computed electron densities in the flowfield agree well with experimental results.

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THE GENERALIZED DIFFERENCE METHOD TO SOLVE BIOT CONSOLIDATION EQUATIONS Li Yinghui, Yang Tianxin 1998, 15(6): 717-725.  Abstract ( )   PDF (334KB) ( )   The Generalized Difference Method (GDM) is studied to solve Biot partial differential equations. The GDM has some advantages on the computational simplicity, the accuracy, and preserving the mass conservation. The difference approximation to the Biot equations and corresponding boundary conditions are presented. A numerical example is given to check this method.

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DOMAIN DECOMPOSITION COMPUTATION ON THE IRREGULAR PATCHED GRIDS Li Jin, Chen Zemin, Zhu Ziqiang, Li Zhongze 1998, 15(6): 726-734.  Abstract ( )   PDF (388KB) ( )   An internal coupling condition which can guarantee the conservation of flux on the irregular patched grids for the domain decomposition method is given. The Euler equations are solved by using the finite Volume method combined with van Leer's flux vector splitting. The TVD character and second order accuracy are realized by adopting a new limiter function. Numerical examples are presented as well.

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SRAPN ANGULAR QUADRATURE SET FOR DISCRETE ORDI NATES METHOD AND ITS COMPARISON WITH TN SET Li Benwen, Wei Xiaolin 1998, 15(6): 735-741.  Abstract ( )   PDF (283KB) ( )   A new angular quadrature set, SRAPN,the successive spherical rings anithmetic progression dividing method is presented for discrete ordinates method.Numerical test for double moments and evaluation against the more precise zonal solution are given and analysed.

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A NEW CLASS OF OBJECTIVE FUNCTIONS FOR FINITE DIFFERENCE SCHEME OPTIMIZING Ju Hongbin, Shen Mengyu 1998, 15(6): 742-747.  Abstract ( )   PDF (270KB) ( )   Optimizing finite difference schemes in spectral space is important for numerical simulations in unsteady flow and aeroacoustics.It is proved that optimized schemes are not always better than high order schemes(in the sense of Taylor expansion).There exists a distance Rcr.Only before the numerical wave traveling this distance,its accumulating error is less than that of a higher order scheme.Beyond this distance,the regularity is reversed.This distance is called here the critic distance of an optimized scheme.It is necessary to control this distance in scheme optimizing.The conventional optimizing objective functions are based on amplification factor revealing the error after one time step,by which it is impossible to specify this distance.In this paper,a new class of objective functions is developed based on accumulating errors,which can control the critic distance directly.

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THE CALCULATION OF GROUND STATE He ATOM IN A SMALL AND TIME HARMONIC ELECTRIC FIELD BASED ON HYDRODYAMIC ANALOGY Li Guiqin 1998, 15(6): 748-752.  Abstract ( )   PDF (185KB) ( )   The variation perturbation scheme based on hydrodynamic analogy to Schrödinger equation is adopted and the perturbed wavefunction for He atom in the ground state in a small and time dependent harmonic electric field and the polarizabilities and 1 st resonance frequency are calculated. Comparisons between the calculated results and experimental ones are also given.

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CALCULATION OF DIRECT RADIATIVE EXCHANGE AREAS USING MONTE CARLO METHOD Xing Huawei, Shen Feng, Liu Zhaohui, Zheng Chuguan 1998, 15(6): 753-756.  Abstract ( )   PDF (167KB) ( )   Zone method has been commonly used in radiative heat transfer calculation in industry, but it has difficulty in calculating multi integration for solution of direct radiative exchange areas, and also in treating with non uniformal gas absorbing and scattering. this paper presents Monte-Carlo method for solution of direct radiative exchange areas, compiling the corresponding program such areas between the zones of enclosed square system filled with uniform absorbing medium are calculated, and comparing the numerical results with analytical ones.

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STUDIES ON QUANTUM CHEMISTRY CALCULATIONS OF STRUCTURE AND PROPERTIES OF ALUMINATE CEMENT MINERALS Li Beixing, Feng Xiuji, Min Xinmin 1998, 15(6): 757-760.  Abstract ( )   PDF (157KB) ( )   SCC-DV-Xα computational method of quantum chemistry is used to study the relationship among structure, property and chemical bond of five cement minerals in the system CaO-Al2O3, as well as the effect of sodium ion entering into its lattice on property of the mineral. The calculated results show that the order of Ca-O covalent bond strength is C3A < C12A7 < CA < CA2 < CA6,and the strength of their Ca-O bonds is all less than that of the Al-O bonds, which are consistent with the experimental results of hydration activity of the corresponding cement minerals. After sodium ion entering into the structure of C3A, Al-O bonds will be strengthened, the hydraulic activation energy is increased, and the density of states is decreased. These are believed as the main reasons for the decrease of hydration activity of doped C3A.

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CALCULATING PHYSICAL PROPERTY PARAMETERS OF OIL GAS RESERVOIR BY COMBINING CUSI NETWORK WITH GENETIC ALGORITHM Chen Zunde, Jiang Xianyi, Wang Jianhua 1998, 15(6): 761-768.  Abstract ( )   PDF (250KB) ( )   Physical property parameters of oil gas reservoir(i.e.reservoir parameters) are important in reservoir description. Considering both the complexity of finding reservoir parameters by seismic data and the shortages of the nonlinear mapping of BP network which needs complete sample information and is the low effciency of learning.This paper presents a method combining Complete Utilization of Sample Information (CUSI) with genetic algorithm(GA) to calculate these parameters.

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A MATHEMATICA SOFTWARE FOR THE COMPUTATION OF SU(3) CLEBSCH GORDAN COEFFICIENTS USING GEL'FAND BASIS Jia Yingdong, Min Xinmin, Yan Mulin 1998, 15(6): 769-775.  Abstract ( )   PDF (301KB) ( )   Based on Gel'fand technique and the analysis of phase conventions,a Mathematica programmes worked out for the computation of Su(3) Clebsch Gordan coefficients (CGCs).The results agree with those obtained from the generalized Condon-Shortley Convention.