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25 September 1996, Volume 13 Issue 3 Previous Issue    Next Issue

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NUMERICAL SIMULATION OF DEFLECTION YOKE Lei Wei, Tong Linsu, Tang Hui 1996, 13(3): 257-263.  Abstract ( )   PDF (274KB) ( )   Since the structure of deflection system is complicated, FEM (Finite Element Method) may be suitable to calculate the system. However, the deflection field has no definite boundary, it must be taken as an open boundary problem. In view of some peculiarities of deflection system, an improved method FEM-BEM is proposed for analysis. This method is different from ordinary hybrid method, it not only improves the accuracy of deflection traces, but also decreases the requirement for computer speed and memory.

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SIMULATION OF PULVERIZED COAL COMBUSTION IN A COMBUSTIOR OF LARGE VELOCITY DIFFERENCE JETS BY PARTICLE CONTINUUM-TRAJECTORY MODEL Zhang Jian, Zhou Lixing 1996, 13(3): 269-275.  Abstract ( )   PDF (243KB) ( )   A mathematical model of pulverized coal combustion is formulated and developed based on a particle continuum-trajectory model.An overall iterative solution procedure for reactive two-phase flows is also proposed.The corresponding CCVC computer code has been developed for calculating two-dimensional, recirculating,reactive,two-phase turbulent flows.It is utilized to numerically simulate the pulverized coal combustion in a combustor of large velocity difference jets which at plesent is widely used in coal fired boilers.

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NON-OSCILATION SHOCK-CAPTURING METHOD WITH HIGH ORDER OF ACCURACY Li Haidong, Ren Yuxin, Liu Qiusheng, Shen Mengyu 1996, 13(3): 276-282.  Abstract ( )   PDF (239KB) ( )   A derivate's formula is presented based on the analytical discrete method and can achieve arbitrary order of accuracy firstly.It is combinated with Roe's flux differential splitting technique and high accuracy flux filter midmod,to construct a kind of nonoscillatory shock-capturing method with high order of accuracy and high resolution.

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RECONSTRUCTION OF PROFILE FROM LINE INTEGRAL DATE USING NEURAL NETWORK IN TOKAMAKS Zhu Sizheng, Zhang Lei 1996, 13(3): 283-288.  Abstract ( )   PDF (205KB) ( )   Amultilayer feedforward neural network is used to reconstruct spacial distribution from line integral data along survey chords through the plasma in tokamaks. The BFGS quasi-Newton algorithm is employed to accelerate the convergence of standard error backpropagation (BP) greatly.

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COMPUTER SIMULATION OF μ-PIXE SPECTRA FOR MULTI-LAYER AND INHOMOGEOUS TARGET ANALYSIS Dai Zhongning, Ren Chigang, Yang Fujia 1996, 13(3): 289-294.  Abstract ( )   PDF (205KB) ( )   A computer program is developed for simulation of μ-PIXE spectra for multi-layer and inhomogeneous thick target analysis. The program can allow users to define three dimensions multi-layer and inhomogeneous target in terms of slices and inclusions. Computations of 2D maps and line scan distribution have been performed on a target consisting of a spherical Fe inclusion embedded in a Si block. The Cu mesh is also used to test the program. The line scan result agress well with that obtained from experiment

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ON THE NUMERICAL SOLUTION OF THE SECULAR TRAPPED ION TEMPERATURE GRADIENT MODE EQUATION Li Jiquan, Mu Zongze, Huang Lin 1996, 13(3): 295-299.  Abstract ( )   PDF (186KB) ( )   The eigenvalue problem of the secular trapped ion temperature gradient mode is solved by employing invariant imbedding method. The numerical methods removing the singularity of the eigen equation at zero point are presented for even mode and odd mode, respectively. The calculation for a concrete physical problem is outlined.

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THE EFFECT OF MEDIUM MOTION ON NEUTRON TRANSPORT AND ITS CALCULATION STUDIES (PART 1. EFFECT OF THE THERMAL MOTION) 1996, 13(3): 300-304.  Abstract ( )   PDF (188KB) ( )   In speedy flowing medium at high temperatures the neutron transport behaviour will be affected by the macroscopic motion of the medium and the thermal agitation of the nuclei within the medium. The influence of the-macroscopic motion of the medium on the neutron transport can be described directly by the neutron transport equation (see details in Part 2.). The microscopic characteristic at high temperature can be described by studying the thermal agitation of nuclei, and its effect will be refleeted in the neutron nuclear cross section data, In this paper, the effect of the thermal motio of nuclei on neutron nuclear cross section data is studied. The Doppler broaden-problem of the Breit-Wigner single and multi-level and indinstinguishable resonance cross sections at high temperature are discussed in details.

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THE EFFECT OF MEDIUM MOTION ON NEUTRON TRANSPORT AND ITS CALCULATION STUDIES Part 2. The Problem for Neutron Transport Equation in Speed Flowin Medium and Its Computational Study Liu Chengan, Huang Wenkai, Tian Dongfeng 1996, 13(3): 305-309.  Abstract ( )   PDF (182KB) ( )   The problem of neutron Transport equation in speed flowing medium is outhined The equation of neutron transport in flowing medium is derived and the computer code is developed Taking a ideal high criticality system as an example, numerical results for the given velocity field are presented. The effect of speed flow of medium on the reactivity of system(time constant of neutron multiplication) is also analysed.

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LATTICE MODELS FOR SOLVING-CONVECTION-DIFFUSION EQUATIONS Zou Xiufen 1996, 13(3): 310-314.  Abstract ( )   PDF (182KB) ( )   The lattice method of fluid dynamics is extended to solve general mathematical physics equations, hence the simple and complex models are for build for solving convection-diffusion equtions. Several typical problems are simulated numencelly by using these models. The results compared with those of the lattice gas automata and other numerical methods show good agreement.

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ANALYSIS OF TIME SERIES RECONSTRUCTION FOR FORCED BRUSSELATOR SYSTEM Zhi an Yang, Shi gang Chen 1996, 13(3): 315-322.  Abstract ( )   PDF (268KB) ( )   The topological properties of the delay-time reconstruction transformation of the forced Brusselator system are analysed by means of the Jacobian of the transformation. Topological properties depending on the delay time and on the conditional stability of a time series itself are discussed. The conditional Lyapunov exponent is used to judge whether a time series is good or bad. Results show that the choice of the embedding dimension by using saturation of system invariants is not appropriate.

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SIMULATION OF ELECTRON OPTICAL SYSTEM IN COLOR MONITOR TUBES Lei Wei, Tong Linsu 1996, 13(3): 323-332.  Abstract ( )   PDF (356KB) ( )   In color monitor tubes, electron optical system influences the quality of the whole tube directly. In the wake of development of HDTV and graphic display in workstation, the quality of color monitor (display) tubes must be improved. For achieving display with high resolution, an axiasymmetric electron optical system is adopted to decrease the size of spot on screen. This paper uses SEU-3D program to simulate electron optical system in color monitor tubes. Taking account of the characters of electron optical system in color monitor tubes, this program uses some special methods to analyse the system so that the result obtained from the simulation can fit the actual condition properly.

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APPROXIMATION OF ‖A-1‖∞ Hu Jiagan 1996, 13(3): 333-340.  Abstract ( )   PDF (262KB) ( )   In this paper, a method of approximation of ‖A-1‖∞ is proposed. Some numerical examples are given

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NUMERICAL EXPERIMENTS OF ARTIFICAL VISCOSITY WITH RESPECT TO COMPUTATING SUPERNOVAE EXPLOSION Xie Zuo Heng, Zhang Suo Chun, Wang Wei Zhang, Wang Yi Ren 1996, 13(3): 341-349.  Abstract ( )   PDF (292KB) ( )   In terms of the three basic forms and the eight-various cases of artifical viscosity for the same progenitor madel-"WW88", the numerical simulation has been performed for the whole processes of collapse and explosion of supernovae, and the artifical viscosity influences on compulation of supernovae explosion are investigated through analysis of numerical experimental results.

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SCATTERING RESONANCES IN HOT DENSE PLASMA Yuan Jiankui, Sun YongSheng, Zheng Shaotang 1996, 13(3): 350-354.  Abstract ( )   PDF (177KB) ( )   Using the relativistic self-consistent average-atom model,electron scattering resonances in hot plasma have been studied.For AI plasma at solid density and temperature T=10eV,40eV,70eV,100eV,the resonance scattering structure of phase shift,state density and scattering cross section is given,and the influence upon the dlectron conduction produced by resonance scattering is illuminated by comparing the calculated results with experimental ones.

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OPTICAL FIELD ANALYSIS OF Ge0.05Si0.95/Si HETEROSTRUCTURES SLAB OPTICAL WAVE GUIDE Liu Shuping, Li Guozheng, Liu Enke 1996, 13(3): 355-358.  Abstract ( )   PDF (151KB) ( )   The optical field of Air/Ge0.05Si0.95/Si heterostructures slab optical wave guide is analyzed and its distribution is calculated,which are very useful for design of optical wave guide device

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AN EFFECTIVE ALGORITHM FOR SOLVING (THE LARGEST OR LOWEST) EIGENPROBLEMS OF LARGE SPARSE SYMMETRIC MATRICES Du Yuyue 1996, 13(3): 359-365.  Abstract ( )   PDF (242KB) ( )   An iterative block DL (i.e. Davidson-Lanczos) algorithm is presented for computing a few of the largest (or lowest) eigenvalues and corresponding eigenvectors of very large sparse symmetric matrices. It's convergence rate is also discussed. it overcomes the disadvantages of the DL method which cann't find multiple or clustered eigenvalues, and the convergence speed of the mesent method is far faster than the DL method. Numerical results are compared whith those by the DL algorithm in a few experiments which exhibit a sharp-superiority of the new approach.

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CALCULATION OF THE BOLTZMANN COLLISION MATRIX ELEMENTS Xiang Anping, Zhu Shide, Ren Ji, Xie Wen 1996, 13(3): 366-372.  Abstract ( )   PDF (244KB) ( )   The molecular velocity distribution function and Boltzmann equation in the kinetic theory of gases are expanded in basis of the orthogonal Burnett functions. Hence it is shown that the calculation of Boltzmann collision matrix elements can be realized by computing the reduced integrals, Clebsch-Gordan coefficients and Brody-Moshinsky coefficients. Finally the computatimal mathod of high efficiency and numerical examples are given.

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A NOVEL ALGORITHM FOR COMPOSITION IDENTIFICATION FOR BLENDING PROBLEM Zhang Chenghui, Tan Zhenyu 1996, 13(3): 373-378.  Abstract ( )   PDF (210KB) ( )   A novel parameter identification algorithm is presented which is suitable for raw material blending and batching problem in the industry production. Both application examples and Aimulation results are given

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A MODIFIED IMPLICIT NND DIFFERENCE SCHEME Xia Nan, Chen Peiji, Lu Xiyun, Zhuang Lixian 1996, 13(3): 379-384.  Abstract ( )   PDF (205KB) ( )   An implicit difference scheme solving Euler equations is developed based on NND ideas. Numerical test of diaphragm rupture in one-dimensional shock tube is carried out. The results are compared with those of implicit flux vector fractorization and explicit NND scheme. Extended to axisymmetric Euler equations, this scheme can be used to calculate the transonic flow near M∞=1 for sphere cylinder.