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25 September 1994, Volume 11 Issue 3 Previous Issue    Next Issue

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ADAPTIVE GRID EMBEDDING FOR REFLECTION OF OBLIQUE SHOCK WAVE ON SOLID WALL You Guozhao, Yuan Geying 1994, 11(3): 257-261.  Abstract ( )   PDF (305KB) ( )   Embedding grid is one of adaptive grids. The study makes the Ni's second-order method of finite volume as a base, adopts first-order difference of density as the characteristics Parameter of detecting shock wave, Presents the principles of local fining grids (one divedes into four)and establishes the data structure of fewer memory. The computational results for solid wall reflection of planar oblique shock wave show that the resulotion of shock wave of embedding grid not only appears to be much better than coarse grid, but also slight better than fine grid, and CPU time is slight higher than half of fine grid. Therefore this method facilitates solving of contradiction between computational effeciency and accuracy.

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ANALYSIS OF THE BEAM EMITTANCE ON SG-1 FEL DEVICE Yang Zhenhua, Wu Yupu 1994, 11(3): 262-268.  Abstract ( )   PDF (495KB) ( )   The theoretical analyses of the beam emittance on SG-1 FEL device have been presented in this paper. The measured beam emittance is about (0.4-0.5) rad·cm. From the experimental beam quantity and numerical simulation resalt, it appears that the quantity of beam current is good enough to abandom the 9-m-long beam modulated system, while substituting with 2-m-long drifting focusing regiou.

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THERMAL AND MECHANICAL RESPONSE OF AN INTERNALLY-PRESSED SPHERIC SHELL TO IRRADIATION OF HIGH POWER LASER Chen Faliang 1994, 11(3): 269-277.  Abstract ( )   PDF (510KB) ( )   Tills paper is concerned with the thermal and mechanical response of a spheric shell subjected to an internal pressure and the irradiation of a high power laser beam. In the case of relatively lower intensity laser, the irradiating laser is equivalently regarded as a heat flow conducting into the shell. First, the analytical expressions are induced for the temperature field which varies with time, then with a set of typical geometric and material parameters, heat conduction and thermal elasto-plastic deformation of the shell are numerically analyzed by a large finite element program.As a result, clear patterns of heat conduction are obtained. Finally, the laws of the distribution of the shell deformation with location and time, and the dependence of the shell deformation on the laser inensity and irradiation duration are discussed.

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THE TRAVELING SALESMAN PROBLEM: OPTIMIZATION BY IMPORTANCE SAMPLING SIMULATED ANNEALING METHOD Chen Jun, Chen Tianlun, Huang Wuqun 1994, 11(3): 278-282.  Abstract ( )   PDF (333KB) ( )   The nearest neighbour relation between cities on random triangle lattice has been used to construct a tour subspace and to solve the traveling salesman problem. With importance sampling simulated annealing method and subtour optimization method, the efficiency has been raised obviously. Near optimal solutions are obtained in shorter computation time.

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A NEW CALCULATING METHOD FOR EGUILIBRIUM INGREDIENTS OF SOLID ROCKET PROPELLANT BURNING PORDUCTS Luo Jiting, Ai Chunan 1994, 11(3): 283-289.  Abstract ( )   PDF (394KB) ( )   The calculatin for equilibrium ingredients of solid rocket propellant burning products was performed using the gradient method and Monte Carlo method. By companison between rheir advantages and disadvantages, a new calculating method: gradient-Monte Carlo method is Proposed. numerical results are satisfied with shorter computation and better accuracy.

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THE MULTICHANNEL PREDICTIVE DECONVOLUTION Wang Chengshu 1994, 11(3): 290-296.  Abstract ( )   PDF (347KB) ( )   In this paper,the recurrence formulae for solving partitioning Toeplitz matrix equations are given,and are used in artificial model experiment. Experimental results show that multichannel deconvolution has advantage over single-channel deconvolution. In addition. we defined the meannign of multichannel minimum phase, and verified the definitive stability under one-step prediction case.

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Electron Beam Scattering Trajectories in Langmuir-Blodgett Resists and Substrates: A Monte-Carlo Simulation Lu Wu, Gu Ning, Lu Zuhong, Wei Yu 1994, 11(3): 297-302.  Abstract ( )   PDF (322KB) ( )   The transmitting characteristics of high-energy electron beam in Langmuir-Blodgett (LB) film and multilayer films have been studied. The electron trajectories in LB polymethylmethacrylate (PMMA)resists and Si substrate covered with Cr film have been simulated on computer by applying Monte-Carlo technique.The advantages of LB resists in electron beam exposure lithography have been discussed in this paper.

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INERTIAL CONFINEMENT FUSION-FISSION HYBRID REACTOR AND ITS BLANKET DESIGN Liu Chengsn, Liu Zhongxing 1994, 11(3): 303-308.  Abstract ( )   PDF (360KB) ( )   In this paper the power flow, tritium and plutonium fuel cycle and the possibility of earlier application of the hybrid reactor as fusion energy source have been introduce briefly. A preliminary neutronics study and design of the fast-fission blanket and the suppressed-fission blanket have been performed. The strong and weak point of different blankets and its application prospects have been pointed out.

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THE NUMERICAL CALCULATION OF ATOMIC AND MOLECULAR IONIZATION CROSS SECTIONS IN PARAAL WAVE METHOD Chen Ji, Chen kiaoxi 1994, 11(3): 309-312.  Abstract ( )   PDF (258KB) ( )   Numerical calculations of Partial wave formation for atomic and molecular ionization cross sections are described, specially dealing with high angular momentum terms. Using the extrapolation method, any high angular momentum terms can be included in the calculation and computer time can be saved greatly. The results are satisfatory.

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THE CHARGE TRANSFER AND IONIZATION IN THE COLLISION BETWEEN FULLY IONS AND H ATOM Qiu Yubo, Long Yanqiu 1994, 11(3): 313-320.  Abstract ( )   PDF (424KB) ( )   In this paper, we use classical trajectory Monte-Carlo theory to calculate the collision between fully ions and H atom. By solving the Hamiltonian equations of the system, we obtain the cross sections of charge transfer and ionization. Comparison with the ORNL recommended data shows that our results are in good agreement in the intermediate energy range. The method is correct and the results are satisfactory.

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A MONTE CARLO SIMULATION FOR THE HEAVY-ION INDUCED FISSION AT SUB-BARRIER ENERGIES Qian Xng, Jiang Dongxing, Ye Yanlin, Xu Jincheng, Liu Zuhua, Zhang Huanqiao 1994, 11(3): 321-327.  Abstract ( )   PDF (452KB) ( )   A Monte Carlo simulation code has been written for heavy-ion induced fission at sub-barrier energies with a simple model. The final properties of the heavy fragmemts such as mass, charge, energy, angular distribution and angular correlation have been simulated for complete fusion-fission and transfer-fission. The angles and velocities of the fragments relative to the recoil direction are given in the laboratory system. Consideration covers the combined kinematic effects of the distributions in mass energy and angular for the heavy fragments and pre-scission, post-scission neutron emission. The code can be used as a tool for experiment planning and analysis.

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A VARIABLE MULTIGROUP METHOD FOR CALCULATION IN NON-EQUILIBRIUM RADIATIVE TRANSFER Li Yanwen, Feng Tinggui, Lai Dongxian 1994, 11(3): 328-336.  Abstract ( )   PDF (483KB) ( )   This paper presents a variable multigroup method for calculation in non-equilibrium radiative transfer considered atomic line cross section shift. The use of this method coupling with the conventional multigroup method is descrived and compared with the latter for simple example.

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AN ESSENTIALLY CONSERVATIVE SCHEME FOR 2D HYPERBOLIC CONSERVATION LAWS Jin Baoxia 1994, 11(3): 337-345.  Abstract ( )   PDF (447KB) ( )   In this paper, an essentially conservative scheme is constructed. The scheme can not be written in the usual conservative form but it can be proven that the limit solutions of this scheme are the weak solutions of hyperbolic conservation laws. It is shown that the scheme is second order accuracy, total variation bounded, stable in L1 norm and in L∞ norm, and satisfies the entropy condition.

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NUMERICALLY SOLVING DYNAMICS EQUATIONS OF PLASMA IN FUSION-FISSION HYBRID REACTOR CORE Chen Yiping, Xu Qiang 1994, 11(3): 346-352.  Abstract ( )   PDF (386KB) ( )   Solving dynamics equations of plasma in fusion-fission hybrid reactor core is performed by using Runge-kutta method.Taking different step-length at different time segment is used through computation which can ensure the solution accuracy and save CPU time. There obtained solution curves fully display burning process of plasma in reactor core. In addition, value feedack control method applies to optimization and control of solution curves.

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PARALLEL ALGORITHMS FOR UNSYMMETRIC LINEAR SYSTEMS Liu Xingping 1994, 11(3): 353-361.  Abstract ( )   PDF (479KB) ( )   An algorithm is proposed of the preconditioned generalized conjugate residual method for solving unsymmetric linear systems on a vector multiprocessor, when A is a five, seven or nine-diagonal matrix. The convergence of this iterative method is analysed. In this algorithm the iterations number is vesified to be about the same as for the multiprocessor PGCR algorithms.The resulting preconditioned GCR method has been tested by simulating a parallel-vector computer.Numerical examples indicate that the new algorithm is very efficient, when the vector multiprocessor computation is applied.

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NUMERICAL SIMULATION OF UNDEREXPANDED SUPERSONIC FREE-JET FLOW Ma Dawei, Le Guigao, Yu Shihai 1994, 11(3): 362-366.  Abstract ( )   PDF (297KB) ( )   When a shock wave propagates into a quiescent atmosphere of low pressure from a nozzle orifice, the flow can be simplied by solving a axisymmetric unsteady flow problem. In this paper second order accurate upwind schemes in total variation diminishing (TVD) type is employed for numerically simulating underexpanded supersonic free jet. A satisfactory time-dependent solution has been achieved.

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PLASMA DISPERSION FUNCTION CALCULATION WITH REMOVING SINGULARITY METHOD AND OTHERS Mou Zongze, Zhao Huaiguo 1994, 11(3): 367-374.  Abstract ( )   PDF (365KB) ( )   A numerical method is proposed for calculating singular integrals. It is shown that the procedure is guite powerful for physics calculations with singularity such as the plasma dispersion function and others. In general, the integrals with more complex singularities can be dealt by this method easily.

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THE R-MATRIX PACKAGE AND CALCULATIONS OF ELECTRON IMPACT IONISATION Qian Xingzhong, Pan Shoufu 1994, 11(3): 375-378.  Abstract ( )   PDF (269KB) ( )   The program for Computing electron impact ionization has been written in Coulomb-Born approximation using the program source ready in original R-matrix package,based on the R-matrix theory of electron impact ionization.

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A C-LANGUAGE CODE SIMULATING THE γ-ELECTRON SHOWER Ye Yaming 1994, 11(3): 379-383.  Abstract ( )   PDF (341KB) ( )   A Monte Carlo code writen by C language for simulating the gamma-electron shower in material bas been realized on microcomputer. The programme can actively display the physical process of particle transport and reaction, and can accumulate various spectra selected by the user. The results are stored event by event on the disk and can be retreated afterward. The energy region available is 0.1 to 500MeV, but can easily be extended to lower or higher energies. The code could be used in the area such as gamma detection, protection of nuclear radiation and nuclear medicine.