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25 May 2000, Volume 17 Issue 3 Previous Issue    Next Issue

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A CONSERVATIVE FINITE DIFFERENCE SCHEME FOR RADIAL SYMMETRIC NONLINEAR SCHRÖDINGER EQUATION ZHANG Lu-ming, CHANG Qian-shun 2000, 17(3): 215-220.  Abstract ( )   PDF (159KB) ( )   A new finite difference scheme is proposed for radial symmetric nonlinear Schrödinger equation. This is a scheme of three levels which needn't to iterate. Thus, the new scheme requires less CPU time. Convergence and stability of the new scheme are proved. By means of numerical computation, it is followed that the new scheme is efficient.

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A SIMPLIFIED LINEAR ANALYSIS OF THE HELICAL INSTABILITY OF ARCS GONG Ye, LIU Jin-yuan, WANG Xiao-gang 2000, 17(3): 221-226.  Abstract ( )   PDF (190KB) ( )   A simplified linear analysis of the helical instability of arc plasmas is given. Explicit analytic results are obtained. In case of the applied uniform magnetic field, theoretical results are in good agreement with the experimental measurements. At the same time it also calculates the growth rate of the instability generated by the self magnetic field. The results are in agreement with those of complicated calculations once perfectly.

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AUTOMATIC GENERATION OF THREE-DIMENSIONAL UNSTRUCTURED MESH BY USING INK-SOAK METHOD SU Ming-de, SUN Xi-ming, Hon Y C 2000, 17(3): 227-241.  Abstract ( )   PDF (548KB) ( )   It develops and describes a new method, the ink soak method, for adding boundary points in generation of three dimensional unstructured meshes with Delaunay method. In the Delaunay method, there is an essential defect, i.e., the generated meshes can cross with bound of domain and do not coincide with it, specially in 3D problems. To overcome this difficulty, some complicated methods to check and to correct them were designed. All these method need numerous computational time. This problem is greatly simplified by the present ink soak method. Some 3-D examples are given and demonstrate the efficiency of the ink soak method for unstructured grid generation in complex regions.

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THE PARALLEL ALGORITHM FOR THE CORRELATION ENERGY OF DOUBLE-ELECTRON SYSTEM LIU Lian-jun, XU Jing-wen, LIU Yu-ming, GU Hai-tao, YIN Dong 2000, 17(3): 242-247.  Abstract ( )   PDF (215KB) ( )   The Modified Configuration Interaction method(MCI) is used to calculate the correlated energy of multi-electron systems.For obtaining the higher precision,it calls for huge computings.In order to handle this problem,which will cost much CPU time and memory room if only using one CPU to do it, the parallel multisection recurrence algorithm is adopted by using several CPUs to get the ground state energy of Helium atom at the same time.

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RADIATIVE OPACITY BASED ON THE UTA METHOD SUN Yong-sheng, MENG Xu-jun, YUAN Jian-kui, ZHANG Jing-lin, ZHENG Shao-tang 2000, 17(3): 248-253.  Abstract ( )   PDF (213KB) ( )   The UTA method to calculate radiative opacity is outlined.Some results of Ge and Al are calculated and comparisons with experiments are given.

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NUMERICAL SIMULATION AND DYNAMICAL EFFECTS OF MULTI-COLORED NOISE LIU Shi-jun, BAO Jing-dong 2000, 17(3): 254-258.  Abstract ( )   PDF (179KB) ( )   An approach is proposed for producing a multi-colored noise from red noise to green one, and the correlation and spectral functions of this noise are given. It uses an integral-closed relation to simulate the multi-colored noise, and employs the Runge-Kutta algorithm to solve the Langevin equation itself. The average feature of the transport for a Brownian particle moving in a ratchet periodic potential is studied. The results show that the direction of the current driven by the green noise is opposite to the one driven by the red noise, and there is a noise with certain color which makes the current reversal.

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NONLINEAR LONG-WAVE DISTURBANCES EXCITED BY LOCALIZED FORCING Meng Lu, LU Ke-li 2000, 17(3): 259-267.  Abstract ( )   PDF (434KB) ( )   It generalizes the theory developed by Helfrich and Pedlosky[1] for time-dependent coherent structures in a marginally stable zonal flow by including forcing.Such forcing could be due to topography or to an external source.By using a perturbation method,the nonlinear differential equation is obtained for governing the evolution of a disturbance excited by those forcings.Some general features of the excited disturbance are given by numerically solving the governing equation.It further studies the interaction between solitary wave and topography and reveals that the solitary wave can always climb over the topography,but depending on the initial conditions of solitary wave and the height of topography,the initial solitary wave could keep most of its mass or be fissioned into two solitary waves traveling in opposite directions.

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CHARGE LOSS CROSS SECTIONS FOR 10Neq+(q=1~3) LIU Zhi-jing 2000, 17(3): 268-272.  Abstract ( )   PDF (153KB) ( )   It presents calculation of charge cross sections for multi-charged ion 10Neq+ collision with neutral atom H and He using Thomas-Fermi Approximation and Binary Encounter Approximation,also calculations of electron momentum distribution and ion potential function distribution.

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THE EQUATION AND THE NUMERICAL ANALYSIS OF STATIC FLUID SURFACE IN REVOLVING SYMMETRICAL TANK UNDER LOW GRAVITY CHENG Xu-duo, WANG Zhao-lin 2000, 17(3): 273-279.  Abstract ( )   PDF (197KB) ( )   By equilibrium equation of mechanics, the equation of static fluid surface in revolving symmtrical tank under low gravity has been derived. Boundary condition of contact angle is given. Finally, using Runge-Kutta method, numerical results are attained with the shape of static fluid surface drawn by the computer. Features of the computing method are analysed as well.

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IDENTIFICATION OF PRIMARY GAMMA RAYS AND PROTONS IN YBJ-ARGO EXPERIMENT KONG Fan-min, FENG Cun-feng, ZHANG Xue-yao, FU Yu, ZHANG Nai-jian, HE Mao, WANG Cheng-rui, TAN You-heng 2000, 17(3): 280-285.  Abstract ( )   PDF (216KB) ( )   The differences of space distributions and time profiles between the γ-ray and proton induced showers in YBJ-ARGO experiment are studied using Monte Carlo simulation data.An artificial neural algorithm is used to identify the primary γ-ray and proton induced showers.It is shown that the separation of γ-rays and protons can be achieved with a good efficiency in the energy range of 0.1~10 TeV.

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EFFECTS OF THE TILT OF MIRRORS FOR THE VIRTUAL CONFOCAL UNSTABLE RESONATOR ON LASER TRANSMISSION FU Han-qing, WANG Tai-chun 2000, 17(3): 286-292.  Abstract ( )   PDF (248KB) ( )   In this paper, we first analyse by the geometric optics method the relation of angular sensitivity and deviation distance sensitivity with the magnification m and tilt angle β respectively. Then the changes of near-field phase and far-field intensity, which were led to by the tilt of a single mirror and two mirrors with different deviated direction respectively, are computed and analysed by C-6 code. The computational results indicate that the tilt of mirrors really lead to the near field phase changing from uniform to nonuniform distribution and the laser beam quality from high to low.

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GENERATION OF FINITE ELEMENT MESH FOR ARBITRARY PLANAR DOMAINS YANG Xiao-dong, LIU Chun-tai, SHEN Chang-yu, CHEN Jing-bo 2000, 17(3): 293-297.  Abstract ( )   PDF (171KB) ( )   Based on Delaunay triangulation an algorithm is presented for generation triangle mesh over any planar domain which have complicated characteristic constraints.Charateritic constraints in a planar domain can be constructed by point,line,circle,arc,spline curves,open loops and closed loops which are made up of them.

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STUDY OF SCATTERING PROPERTIES OF X RAYS IN INTENSIFIERS GUO Jin-chuan, NIU Han-ben 2000, 17(3): 298-306.  Abstract ( )   PDF (362KB) ( )   The interaction processes of bremsstrahlung X rays with CsI:Na scintillator of different thickness(200~400 μm) are first simulated by means of Monte Carlo analysis. The energy spectra of exit photons from CsI:Na are presented, which are used as the incident spectra on iron, the constituents of the inner electrodes and shell of intensifiers. The backscattering properties of X rays in intensifiers are analyzed. The potential producing bremsstrahlung X rays is 20~120 kV. Results show that with the increase of X ray tube potential the number of backscattered photons gets bigger and their mean energies increase rapidly.

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SOLVING PROCESS OF THE HEAT BALANCE EQUATION FOR GAS COOLED CURRENT LEADS NAN He-li 2000, 17(3): 307-313.  Abstract ( )   PDF (265KB) ( )   The solution of the heat balance equation for gas-cooled current leads is presented. In the process of searching for the final solution, the functional relation of the dependent parameter to the independent parameters must be obtained first. Then, the domains of definition for the parametric equations should be turned to the form containing only independent variables, instead of that including dependent variables as well as independent variables. Moreover, in the existential range of the all solutions for the parametric equations, the part in which the trivial solutions exist should be determined and excluded from consideration. Only whenroblems are given and discussed.

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A FAST ALGORITHM OF JACOBIAN MATRIXES IN IMAGE RECONSTRUCTION OF EIT QIN Shi-lun 2000, 17(3): 314-318.  Abstract ( )   PDF (197KB) ( )   The calculation of Jacobian matrixes constitutes the great mass of the calculation in image reconstruction of electrical impedance tomography. A fast algorithm of the matrix is investigated based on perturbation technique. It can reduce the calculation on a large scale. An example given here shows the effectiveness of the algorithrn.

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THE ELECTRONIC STRUCTURE AND ABSORPTION SPECTRUM OF RUTIL TiO2 CRYSTAL WITH F TYPE COLOR CENTER CHEN Jun, LIN Li-bin, LU Tie-cheng 2000, 17(3): 319-325.  Abstract ( )   PDF (260KB) ( )   The electronic structure of rutile TiO2 crystal with F-type color center is studied by using the H-like wave function and Discrite Variation method with the relaxation of ions around color center,and their energy band,density of states are obtained.The results show that F and F+ center have donor energy level in forbidden band,and F2+ center has acceptor energy level in forbidden band.The optical transition energy are 0.85 eV and 1.67 eV for F and F+ center,respectively.The optical absorption peaks 1.7μm(0.75 eV),760 nm(1.61 eV) in the reduced sample of TiO2 are due to the F and F+ center,and a transferring of F+→F existed.

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REGULARIZING ITERATIVE METHOD FOR SOLVING INVERSE PROBLEM OF ONE-DIMENSIONAL WAVE EQUATION ZHANG Da-li, WU Jian-Cheng, LIU Jia-qi 2000, 17(3): 326-330.  Abstract ( )   PDF (104KB) ( )   A new computing method is proposed for solving inverse problem of one-dimensional wave equation on seismic prospection by using difference-discrete regularization method. The numerical results of simulation are given and show the method is faster convergence and more powerful noise-resistance.

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MONTE CARLO SIMULATION ON LOW ENERGY ELECTRON SCATTERING IN POLYBASIC MEDIUM——BASED ON MEAN CROSS SECTION METHOD TAN Zhen-yu, HE Yan-cai 2000, 17(3): 331-336.  Abstract ( )   PDF (231KB) ( )   Using Monte Carlo method of low energy electron scattering in polybasic medium based on the mean cross section,the scattering process of the low energy electron in the range of E0≤5 keV has been numerically simulated.A series of the results,such as the backscattering coefficients,the energy spectrum and angular distribution of backscattered electrons,the interaction range of both primary and backscattered electrons in medium,energy dissipation distribution,have been obtained and compared with those calculated by the method of determining scattering center.The calculated results by both methods are in excellent agreement widely,showing the effectiveness and reliability of the method based on mean cross section.Also,the calculated results on the angular distributions of backscattered electrons seem not to follow a cosine law for both the lower energies as well as the medium with larger mean atomic number.

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THE APPLICATION OF DATABASE TECHNIQUE IN THE OFFLINE DATA ANALYSIS ZHAO Jia-wei, ZHANG Zi-ping, CHEN Hong-fang, SUN Yi, ZHANG Lei, RONG Gang 2000, 17(3): 337-340.  Abstract ( )   PDF (173KB) ( )   The application of database technique for solving some problem in high energy physics analysis is discussed. By designing a connection program between the SQL language database and the software package PAW(Physics Analysis Workstation) commonly used in high energy physics analysis, the data processing capability, conveniency and practicability of PAW are greatly increased. This shows a new application field and prospect of databese technique in offline data physical analysis.