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31 December 1992, Volume 9 Issue S2 Previous Issue    Next Issue

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ANALYZING ELECTROMAGNETIC SCATTERING PROBLEMS USING FINITE-DIFFERENCE TIME-DOMAIN ALGORITHM Guo Liqang, Li Mingzhi, Ge Debiao 1992, 9(S2): 655-660.  Abstract ( )   PDF (609KB) ( )   FDTD is a numerical method to seek the solution of Maxwell equations by marching in tihme domain, which can be used to analyze the interactions between electromagnetic fields and complicated objects. The fundamentals of FDTD are discussed in this paper, and some useful skills introduced. In particular, complex field components are used in time-harmonic case in order to obtain smooth output for phase. Finally, some examples are provided.

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THE CALCULATION OF IEMP IN THE PROLATE SPHEROIDAL CAVITY Zhou Hui, Chen Yusheng 1992, 9(S2): 661-663.  Abstract ( )   PDF (226KB) ( )   In this report we have presented the forms of Maxwell's equations and the source equations in the ellipsoidal-hyperbolidal coordinates, obtained the numerical results of IEMP produced in the metallic ellipsoidal cavity when its major axis is parallel to the γ flux by using finit difference method.

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THE RESEARCH OF INSTABILITY AND CHAOS IN COUPLED LORENZ MODEL Zu Jifeng, Song Dan, Shen Ke 1992, 9(S2): 665-668.  Abstract ( )   PDF (289KB) ( )   At first, output equations of coupled-Lorenz lasers are changed into coupled Lorenz Model equations with coupling factor β, and the instability and chaos of the output are stimulated in numerical value, the average output power of coupled Lorenz lasers in self-pulse and chaotic regions is studied at last in this paper.

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ARNOLD DIFFUSION IN THIN LAYER PUMP Wang Guangrui 1992, 9(S2): 669-671.  Abstract ( )   PDF (211KB) ( )   In this paper, numerical studes are performed on a model for a coupled standard mapping to investigate the Arnold diffusion. We present estimates diffusion coefficient as a function of coupling constant b, the nonlinearity parameters k and the number of iteration N, and compared with the results of the theoretical. We estimates the diffusion coefficent along the thin stochastic layer of the J-ψ motion. For samll parameter values, theoretical pradiction agrees well with numerical result.

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APPLICATION OF PSEUDOSPECTRAL METHOD TO SIMULATION FOR THE DYNAMICS OF DRIVEN DRIFT-WAVES He Kaifen 1992, 9(S2): 673-677.  Abstract ( )   PDF (342KB) ( )   Pseudospectral method is used to solve the driven-damped 1-d nonlinear drift-wave equation. Some problems in the computation are discussed.

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PHENOMENON OF KINKS IN THE SYSTEM OF J-J TYPE Wang Congshun, Zhou Tianshou 1992, 9(S2): 678-682.  Abstract ( )   PDF (367KB) ( )   By Studying and calculating poincare section. power spectrum and Lyapunov exponents about the system of J-J type, we have obtained:(1)When some parameters vary and the rotating number is fixed, there is the route of quasi-period to chaos, which embodies that the fixed circle produces kinks at first, and with Jerking-lengthening and compression of kinks, then develops into station of chaos.(2) There is only outer-kinks in the single system of J-J type, and there are two kinks, inter-kinks and outer-kinks in the double system of J-J type.

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A FRACTAL MODEL-RANDOM BRANCH GROWTH Dai jianbiao 1992, 9(S2): 683-686.  Abstract ( )   PDF (245KB) ( )   In this paper we provide a theoretical model of fractal growth which bases on potential theory and random walk. It is characterized by branch and growth and can be used to study or simulate the river branch, breakdown, discharge and even the growth.The fractal dimension D has been measured; the relationship between D and the probability of growth outwards P-out(indicates the potential condition u(r) has been discussed.We compared the computer simulations with some experiment facts, facts, the results were satisfactory.

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EVALUATING THE FRACTAL DIMENSION OF RANDAM FRACTAL CURVES Wu Zhensen, Guo Lixin 1992, 9(S2): 687-692.  Abstract ( )   PDF (395KB) ( )   In this paper we present a new method-local accumulated deviation method for evaluating the fractal dimension of curves or one-dimensional(1D) surfaces. Our method is tested on various types of curves for Weierstrass-Mandelbrot fractal function and fractal Brownian motion with known fractal dimension. The results are good agreement with the theoritical values. Finally, using Monte-Carlo method, we simulated the randam rough(1D) surfaces with Gauss spectrum, and the new method is applied to data from simulating surfaces.

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LIQUID PHASES SEPARATION OF BINARY SYSTEM: TWO DIMENSIONAL MODEL AND COMPUTER SIMULATION BY NUCLEATION DECOMPOSITION Pan Mingxiang, Sun Jirong, Chen Xishen 1992, 9(S2): 693-696.  Abstract ( )   PDF (365KB) ( )   With the classical Nucleation theory and the combination of Monte Carlo method, the two dimensional model of liquid phases separation for binary system is present. It consists of three parts of nucleation, diffusion and growth The some methods dealing with problem of surface energy in the growth of new phase are raised. The principal procedure is shown for the simulation of phases separation with computer.

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THE COMPUTER SIMULATION OF FRACTAL DIMENSION MEASUREMENT OF ACTUL FRACTAL Yang Guowei, Mao Youde 1992, 9(S2): 697-699.  Abstract ( )   PDF (207KB) ( )   The paper makes use of computer to simulate the law of variation fractal dimension D. in measurement of actul fractal, under differen conditions by N(ε)∞ε-D. The meaning of the law and conditions are discussed on reatistic application.

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INTERACTION OF SECOND OPTICAL SOLITONS Chen Lujun, Liang Changhong 1992, 9(S2): 700-702.  Abstract ( )   PDF (223KB) ( )   Based on the nonlinear schodinger equation, the interaction between a couple of second order or quasi-second order optical solitons is numerically investigated by the split-step Fourier transformation method. This let us have a good understanding of the properties in the interactions, which is referential for the utilization of second solitions to communication.

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NUMERICAL ANGLYSIS OF STIMULATED RAMAN SCATTERING IN SOLITON DISPERSION REGIME OF OPTICAL FIBERS Yao Duanzheng, Xiong Guiguang 1992, 9(S2): 704-706.  Abstract ( )   PDF (193KB) ( )   The numerical method of the split Fourier transform is used to investigate the correlation between the shift and nonlinear interaction length, which is induced by stimulated Raman scattering in optical fiber under the condition of the anomalous(soliton)dispersion regime.

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THE INFLUENCE OF DIPOLE ON THE HYDROGEN-BONDED CHAINS Xiao Jiaxin, Tian Baoguo 1992, 9(S2): 707-709.  Abstract ( )   PDF (195KB) ( )   In this paper we give a model of dipole interaction in hydrogen-bonded chains, Using Runge-Kutta-Nystrom method we numerically solve and discuss the above dynamic problem.

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STUDY OF ORDER-DISORDER PHASE TRANSITION IN ALLOY Liu Yunpeng, Zheng Maosheng 1992, 9(S2): 711-713.  Abstract ( )   PDF (254KB) ( )   The percolation model of order-disoder phase transition is established, and the relationship between the transition temperature and the composition of binary system is given. Monte Carlo simulations and avialable experiments show that this relationship is correct.

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COMPUTATION OF AUXILIARY FUNCTIONS IN MOLECULAR INTEGRAL UP TO ARBITRARY ACCURACY(Ⅰ)EVALUATION OF INCOMPLETE GAMMA FUNCTION BY FORWARD RECURRENCE SCHEME Li Yanxin, Dong Xialan, Pan Shoufu 1992, 9(S2): 714-716.  Abstract ( )   PDF (207KB) ( )   Two inequalities of incomplete Gamma function are given for the domain v∈[0,-∞) and z∈(-∞,0].Based upon the inequalities, we derive the round off error propagation regularity of the forward recurrence scheme. Our numerical experiments indicate that the relative error predicated by our regularity almost coincides with that from authentic regularity in the whole domain of v and z.

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COMPUTATION OF AUXILIARY FUNCTIONS IN MOLECULAR INTEGRAL UP TO ARBITRARY ACCURACY(Ⅱ)——EVALUATION OF THE FIRST KIND MODIFIED SPHERICAL FUNCTION BY FORWARD RECUTRRRENCE SCHEME Li Yanxin, Dong Xialan, Pan Shoufu 1992, 9(S2): 717-718.  Abstract ( )   PDF (183KB) ( )   With regard to evaluation of auxiliary function Iμ(x)up to arbitrary accuracy, it is required that the forward recurrence scheme of the function can be used as far as possible. Applying a new inequality found by us, we have set up a criterion which can accurately decide whether the requirement can be met.

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THE MOLECULAR DYNAMICS SIMULATION OF LOW ENERGY CLUSTERS IMPACTING ON GOLD THIN FILMS Pan Zhengying 1992, 9(S2): 719-720.  Abstract ( )   PDF (172KB) ( )   The aluminum and carbon clusters impacting on gold thin films have been studied by molecular dynamics(MD) simulation. The initial energies are 0.1~0.2keV per atom. The energy spectra of target recoil atoms have been calculated as a function of time. It was shown that the target atoms may achieve more than twice of the maximum recoil energy in a single elastic collision. The effect has been traced to multiple hits by cluster atoms and the collisions between moving atoms.

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MOLECULAR-DYNAMICS STUDY ON SMALL SILICON CLUSTERS Gong Xingao, Zheng Qingqi, He Yizhen 1992, 9(S2): 721-722.  Abstract ( )   PDF (148KB) ( )   By use of molecular-dynamics and simulated annealing technique, we have studied the structural properties of Sin cluster at zero and high temperature. The results are in good agreement with ab-initio calculations.

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NUMERICAL MODELLING STUDIES FOR THE SECONED STREAM OF CLIMATIC RESEARCH 1992, 9(S2): 725-730.  Abstract ( )   PDF (544KB) ( )   Several climatic models(atmosphere model, ocean model and coupled ocean-atmosphere model) have been improved and developed based on the climatic dynamics. The interactions between air and sea. air and land and cloud and radiation are considered in phsical processes.Climatic predicta-bility is studied on seasonal and interannual time scale to sustain the second itemf WCRP. The numerical tests show that some of the results are encouraging and some display a number of qustions. But with both of molels improving and data getting being perfected the item is hopeful from scientific strategy.

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A STUDY OF MESO-β SCALE MODEL:NUMERICAL SIMULATION OF TOPOGRAPHIC CLOUD Xu Huanbin 1992, 9(S2): 731-734.  Abstract ( )   PDF (333KB) ( )   This paper describes a nonhydrostatic and full-elastic meso-β scale model including the effects of topography. By use of the two-dimensional version of this model the topographic clouds have been simulated. The results of simulation indicate that: not only the formation and evolution of topographic cloud but also various phenomena of airflow over mountain, such as foehn wind, dowuslope wind and "hydraulic jump" named in hydraulics, have been well reappeared.

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A METHOD TO REDUCE THE VIRTUAL GRAVITY WAVES IN A NUMERICAL MODEL Huang Yahui, Zhou Xiaoping 1992, 9(S2): 735-736.  Abstract ( )   PDF (147KB) ( )   In this paper, a method to reduce the virtual gravity waves in numerical model is proposed. An experiment of a case using this method is carried out. The result shows that the "noise" is weaken not only in the initial field but also also in the computational processes, and the simulated results are improved.

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PROBE INTO AN EXPLICIT TREATMENT WATER SUBSTANCE PLAYING A ROLE IN PRECIPITATION SYSTEM IN NUMURICAL SIMILATION EXPREIMENT Wu Qing, Yin Dechang 1992, 9(S2): 737-744.  Abstract ( )   PDF (546KB) ( )   In this paper, the model was designed the domain with 11 vertical levels and has been replaced cumulus parameterization with an explicit treatment of moist thermodynamics. The results show:(1) it is vast potential to design an explicit model for precipitation prediction.(2) Taking account of explicit scheme is improved in heign field. Surface pressure field and surface temperature.

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MESOSCALE METEOROLOGICAL NUMERICAL MODEL Shi Yognnian 1992, 9(S2): 745-748.  Abstract ( )   PDF (288KB) ( )   The object of mesoscale meteorological research is the atmospheric phenomena, to which the geostrophic balance similarity can not be applied, but the the hydrostatic balance similarity still can be applied. The range of its horizontal scale is about 2.5 to 2500 km. The numerical model for the mesoscale meteorological research should have such features as: high horizontal resolution, description of underlying surface with high precision and high resolution, detailed parameterization of physical processes, utmost reduction of the reflection of gravity wave onupper and lateral boundaries. lower boundary conditions coinciding with real situations and compressible(at least anelastic) mass continuity equation. A mesoscale me-teorological numerical model, which possesses the features mentioned above, is simply intro-duced in this paper including: basic equations, parameterization of physical processes, boundary condi-tions and numerical integration methods.

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A MESOSCALE NUMERICAL MODEL AND SIMULATION OF THE PBL AND ATMOSPHERIC DIFFUSION OVER COMPLEX TERRAIN Cheng Linsheng 1992, 9(S2): 749-757.  Abstract ( )   PDF (558KB) ( )   The design and development of a general primitive equation model is described in this paper. The model is three-dimensional and is particularly suitable for complex terrain and planetary boundary layer(PBL) processes as well as atmospheric diffusion. The model utilizes a high resolution parameterization, which includes surface heat, moisture and momentum fluxes. The ground temperature is predicted from a surface energy budget and a slab model. Short-and long-wave radiation is considered in the surface energy budget. In order to improve the description of high resolution PBL physical processes, a turbulence kinetic energy(TKE) equation is derived and K-e closure is adopted.The basic and averaged equations is first presented in this paper. Then a consistent set of the averaged equations was derived in terrain-following coordinate systems, in which the Exner function was applied to pressure gradient force. After introducing TKE equation and K-e closure, we discuss particularly the PBL parameterization. In the numerical method, and implicit cubic spline-function method was developed to compute the advection terms.In order to test the consideration of physical processes, the PBL-parameterization, the finite-differencing scheme and the boundary condition, we conducted a comparison of observational and simulative results of two-dimensional model with high spatial resolution. The horizontal resolution both the real terrain data and themodel are 1km. The results of 12-h and 24-h simulations for the PBL processes and the contaminant(TSP, S02) diffusion in Lanzhou Basin during the winter showed that this model is capable of successful simulating the PBL and contaminant diffusion processes under a stable zonal flow weather condition. However, it is necessary to run three-dimensional model for complex weather condition.

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A GENERAL INVERSE FORMULATION PRINCIPLE OF PERFECT CONSERVATIVE SCHEME AND ITS APPLICATIONS hong Qing 1992, 9(S2): 758-764.  Abstract ( )   PDF (564KB) ( )   A principle of inverse compensation computation and concept of perfect conservative scheme which can provide new approach for improvement of traditional schemes is set up in this paper. Especially, two direct formulation theroms of square and weighted square perfect conservative time difference scheme, which can solve their problem of nonlinear computational instability thoroughly and reasonably, is given here. This compensation principle and inverse approach is also workable in formulation of time-space discrete perfect conservative scheme and that of other characteristic properties.The time-space discrete perfect conservative schemes of(weighed) square and non-square(kinetic) energy, enstrophy and angular momentum property is further realized respectively by application of inveres compensation theory to improvement of a traditional numerical weather prediction spectral scheme of barotropicprimitiveequation.The numericalexperiments of them showthatperfectconserva-tive schemes can improve computational precision, prolong valid integral time and reduce the amount of computation greatly in comparison with the corresponding traditional scheme, and perfect conservative schemes of some "good" property can solve the problems of nonlinear computational instability and nonlinear convergence in practice.

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DYNAMIC-STOCHASTIC MODEL OF WEATHER FORECASTING Cao Hongxing, Zhu Shengming, Jiang Weidong 1992, 9(S2): 765-766.  Abstract ( )   PDF (152KB) ( )   As weather forecasting is summed up as a problem of evolution of meteorological field, a forceasting model is derived by using a statistic discretization for the time differential term in a partial differnetial equation. Medium-range and month weather forecasting experiments are made with dynamic-stochastic difference schemes of barotropic model and two-layer baroclinic model respectively, forecast accuracy of models is comparable to a mumerical model.

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TWO WAYS TO PERFORM INITIAL DATA GRID-SPECTRAL TRANSFORM Lu Xianchi, He Bin 1992, 9(S2): 768-770.  Abstract ( )   PDF (268KB) ( )   The interpolation method and the direct transform method were used to perform initial data grid-spectral transform, and it is shown that the latter one, with somewhat more computation operations, is more suitable to calculate spectral coefficients with much higher accuracy.

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ASSESSMENT OF THE IMPACT OF METEOROLOGICAL SATELLITE SOUNDING DATA ON B-MODEL Wang Zonghao 1992, 9(S2): 771-774.  Abstract ( )   PDF (341KB) ( )   The impact of NOAA 9/10 satellite sounding data(at December 1987) has been assessed by both changes in S1 skill score and root mean square(RMS) errors for 24 and 48 hour forecasts of sea level pressure(SLP) and 500hpa height. A positive impact on RMS errors of up to 11.5% was observed over land for SLP and 8% over ocean for 500 hpa height for forecast period of 48 hour. The verification statistics(for both S1 skill score and RMS error) shows that there is more impact for forecast period of 48 hours than for 24 hours.

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LANDMARK NAVIGATION METHOD OF GEOSTATIONARY METEOROLOGICAL SATELLITE Lu Yaoqiu 1992, 9(S2): 775-777.  Abstract ( )   PDF (244KB) ( )   The main topic of this paper are determination method of the attitude parameters of a geostationary meteorological satellite spin axis and gamma correction parameter of satellite image shifting in direction of east-west by means of landmark measurement. A mathematical equation of the attitude and the gamma determination, including the actual algorithms, is presented. In addition, some other cases of impact image location accuracy are described. Finally, a set of actual results and an error anlysis are presented.

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THE IMPACT OF SAMPLING TO LIKELIHOOD ESTIMATION OF EXTREME DISTRIBUTIONAL PARAMETERS Dong Shuanglin 1992, 9(S2): 778-784.  Abstract ( )   PDF (450KB) ( )   It is indicated in this paper that errors of extreme distributional parameters by maximum likelihood method are obviously different due to different samplings. The difference of the errors is increasing with decresasing of sample sizes. The "beautiful sampling method" by which estimated errors are likely zero, and "the most probable samlping method" which samples are veridical are debeloped. The difference of the errors of the both sampling methods indicates it is required to improve the maximum likelihood method to improve the estimation precision as small sample sizes.

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CONCERNING THE CONSISTENT VERTICAL AND HORIZONTAL RESOLUTION FOR THE ADVECTION EQUATION Liao Dongxian, Zhu Yangqiu 1992, 9(S2): 785-786.  Abstract ( )   PDF (127KB) ( )   Subject to constant computational area, two expressions of optimal vertical gridlength with different accuracy and an expression of consistent vertical gridlength were presented in the case of a single wave. And the corresponding expression of consistent vertical gridlength in the multiwave case was derived-

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AN ANALYSIS ON THE HUMIDITY EFFECT AT THE AVIATION MUSEUM AND RESEARCH INTO THE MEASURES OF ANTTHUMIDITY Wang Bingren, Liu Jianwen 1992, 9(S2): 787-788.  Abstract ( )   PDF (176KB) ( )   This paper analyses the main cause of the humidity effect in spelaeos, i.e. the mixture of humid air advection. It also points out the effectiveness of using sealing door separation to prevent humidity. In the end, there is a research into the measures of spelaeon antihumidity.

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RADIATIVE TRANSFER OF DENSELY RANDOM SCATTERERS AND NUMERICAL CHARACTERISTICS OF SNOW IN REMOTE SENSING Jin Yaqiu, Min Hao 1992, 9(S2): 793-796.  Abstract ( )   PDF (296KB) ( )   Numerical approach to vector radiative transfer equation for a layer of densely random, spherical scatterers is discussed. The polarized brightness temperature and the functional dependence on various parameters are obtained, and are well compared with experimental data in snow remote sensing.

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TERRAIN EFFECT ON COLD-AIR Zhang Leiming, Zhao Ming 1992, 9(S2): 799-805.  Abstract ( )   PDF (436KB) ( )   A mathematical model was developed to simulate the terrain effect on meterology parameter when cold-air flow passing over a mountain terrain. The solar short-wave radiation, ground and atmolphere long-wave radiation, soil heat flux, the diffusion and transport of water vapor, heat and momentum fluxes in the atmosphere' and the Coriolis parameter change with latitude were considered in the model. The resonable phenomena were obtaioned, such as, wind field change, temperature decrease, the abrupt increase of flux and pressure increase etc. The model provides a method and basis for weather forcast and the reseaech of mesoscale processes over complex terrain.

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N-BODY SIMULATIONS AND COMPUTER ALGEBRA FOR DYNAMICAL ASTRONOMY Di Xiaohua 1992, 9(S2): 806-809.  Abstract ( )   PDF (347KB) ( )   The computer simulations of stellar systems and the computer algebra for implementation of analytical algorithms of celestial mechanics are important applications of computer technology to Dynamical Astronomy.The PP, PM, ad P3M methods of N-body simulation and the specialized computer algebra systems for manipulations of Poisson series are described briefly.

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THE PROBLEM OF NUMERICAL STABILIZATION AND STEP-SIZE UNIFORMIZATION IN THE NUMERICAL SOLUTION OF CELESTIAL MOVIGN EQUATION Liu Lin, Liao Xinhao 1992, 9(S2): 810-811.  Abstract ( )   PDF (159KB) ( )   The accuracy of orbital seminajor axis is improved by the energy relation so that the growth of the along-track error in traditional integrators can be controlled. This is called numerical stabilization. The change of step-size can be solved by the transformation of time variable: df=r3/2ds.

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AN ANALYSIS OF THE INTERNAL STRUCTURE ABOUT COADS DATA SET Shen Wenhai, Yao Huadong, Ma Kaining 1992, 9(S2): 815-816.  Abstract ( )   PDF (121KB) ( )   COADS Monthly Summary Trimmed data set contains ninteen variables. Each variable has four kinds of statistics) and one kind of statistics of enery variable is a file. The internal structure of these files are the same. This artical gives a close analysics of the internal structure.

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A DIFFERENCE QUOTIENT-NUMERICAL INTEGRATION METHOD FOR SOLVING RADIATIVE TRANSFER PROBLEMS Ding Peizhu, Mu Yingkui 1992, 9(S2): 817-821.  Abstract ( )   PDF (310KB) ( )   A difference quotient-numerical integration method is adopted to solve radiative transfer problems in an anisotropic scattering slab medium. By using the method, the radiative transfer problem is separated into a system of linear algebraic equations and the coefficient matrix of the system is a band matrix, so the method is very simple to evaluate on computer and to deduce formulae and easy to master for experimentalists. An example is evaluated and it is shown that the method is precise.

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Computer Physics Reports 1992, 9(S2): 822-826.  Abstract ( )   PDF (326KB) ( )