Table of Content

20 January 2000, Volume 36 Issue 1

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The Structural Flexibility Effects on the System Impact Dynamics

LIU Caishan,CHEN Bin

2000, 36(1):  64-69. 

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In this paper, to counter a flexible beam undergoing large overall motion impacting a fixed slope surface under the effects of grativity, the normal contact model is established based on the Hertz theory and non-linear damping term, the tangential contact model is developed by adopting linear tangential contact stiffness to consider the effects of friction force during impact process, and the consistent linear dynamic model including impact is derived by using mode assumption method and Lagrangin equation. Finally, some numerical simulations are executed in the case of the different stiffness of the flexible beam, the effects of the structural flexibility on the system impact dynamics are investigated.

Robust Control Design Based on Randomized Algorithms

SONG Chunlei,WANG Long,HUANG Lin

2000, 36(1):  70-77. 

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This paper combines learning theory with robust control and discusses robust control design problems involving real parameter uncertainty in control systems based on randomized algorithms. It is shown that randomized algorithms can decrease the computational complexity dramatically instead of seeking worst case guarantees. In addition, examples in this paper show that employing randomized algorithms is very efficient and has obvious advantages especially when uncertain interval parameters appear multilinearly or nonlinearly in the characteristic polynomial coefficients.

Weak Convergence of Distribution of Concomitants of Fixed Rank Order Statistics

LI Xiande,CHENG Shihong

2000, 36(1):  44-52. 

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A Sufficient and necessary condition on weak convergence of joint distribution of fixed rank order statistics and its concomitants is obtained, also a sufficient condition on weak convergence of distribution of the maxima of concomitants of selected order statistics is obtained.

Improvement on the Natural Dictionary-ordering Method in Reliability Growth Tests

ZHENG Zhongguo,CAO Dachuang,ZHOU Zhengfa

2000, 36(1):  53-63. 

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In a m-stage reliability growth test, to estimate the lower confidence limit of the reliability of the system in the final stage, randomization is introduced to improve the exsiting natural chain method. Simulation study shows that when the number of stages is one, the randomization method is ideal.

Random Independence and Regressive Independence

GUO Jianhua,MA Wenqing

2000, 36(1):  39-43. 

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Regressive independence means that conditional expectation E(Y|X) of two random variables X and Y does not depend on X. The relation between regressive independence and random independence is discussed, and several necessary and sufficient conditions are presented.

Model for the Microwave Backscattering Mechanisms of Rice

ZENG Qiming,MA Hongbing,ZHANG Tao

2000, 36(1):  131-141. 

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Based on the Vector Radiative Transfer(VRT) theory and the characteristics of the SAR technology, several sub-models for rice backscattering are constructed, including the leaf scattering model, the leaf extinction model, the trunk scattering model, the trunk extinction model and the water reflection model. Then an integrated model for the first-order scattering mechanisms of rice, including all the main physical processes, is achieved. Based on the simulation results, it is discussed that the variations of the rice backscattering coefficient with the date, incidence angle, wave band, and polarization.

A Sufficient and Necessary Condition for the Solvability of General Total Least Squares Problem

LUO Wuan

2000, 36(1):  1-7. 

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It is given that a simplistic proof for the solvability of Total Least Squares problem, extending this idea for General Total Least Squares problem, establishes a sufficient and necessary condition for solvability, proves the uniqueness of the amendment matrix and gives it's expression.

Weak Convergence for Distribution Functions of Induced Maximum

CHENG Shihong

2000, 36(1):  8-19. 

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Let{(X_n,Y_n)} be i.i.d. random vectors with common d.f. F. Under weaker conditions, it is shown in this paper that A_n^-1(Y_{(n, n)}-B_n)→I holds for some nondecreasing function I. Therefore the Nagaraja and David's result is generalized. Moreover, We prove that our conditions are not only sufficient, but also necessary for weak convergence of the sequence (a_n^-1(X_{n, n}-b_n), A_n^-1(Y_{(n, n)}-B_n)). At last, we show that the weak convergences of bivariate extreme values and (a_n^-1 (X_{n, n}-b_n), A_n^-1(Y_{(n, n)}-B_n)) are closely related.

Numerical Approximation of Interface Problems for Elliptic Differential Equations

WU Jinbiao

2000, 36(1):  20-28. 

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It is discussed that the numerical approximation of interface problems for elliptic partial differential equations. For the interface problems with variable coefficients, it is introduced that a particular finite element method combined with the infinite element method to approach the singular solution in the neighborhood of the singular points, and it is proved that the method possesses the same accuracy as the finite element method to the regular solution. Numerical examples are also given.

On the Maximal Solution of the Matrix Equation X+A^TX-1A=I

XU Shufang

2000, 36(1):  29-38. 

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An elegant property of the maximal solution to the matrix equation X+A^TX-1A=I is presented. The property shows that the maximal solution is well-conditioned. Two new iteration methods for finding the maximal solution are proposed. Of these two methods, one is a linearly convergent iteration without matrix inversion, and one is related to Newton's method and quadratically convergent. The convergence analysis is also given. Comparisons have been made with other known methods. In all test problems the new quadratically convergent method appeared to be far superior to the other methods.

Supersymmetry and Shape Invariance of Hartmann Potential

QIAN Shangwu,HUANG Bowen,WANG Deyun,GU Zhiyu

2000, 36(1):  78-82. 

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This article shows that in spherical polar coordinates, the Hartmann potential has supersymmetry and shape invariance in the r dimension and in the θ dimension, and thus it obtains the energy eigenvalues and energy eigenfunctions of this potential.

Study on ZrO₂ Nanoclusters

LIANG Ruisheng,WANG Dehuang,CHENG Humin,WANG Yanqin,MA Jiming

2000, 36(1):  83-86. 

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ZrO₂ nanoclusters embedded in polyviny lalcohol film was made using a chemical method. The TEM image, X-ray spectrum and optical absorbance for ZrO₂ nanoclusters were determined experimentally. The average particie size of ZrO₂ nanoclusters embedded in polyviny lalcohol film is about 7.0nm. The band-gap of ZrO₂ nanoclusters determined at the room temperature absorbance curve is 3.024 eV.

Analysis of Satellite Image Characters of Severe Storm Rainfall During the Flood of Yangtze River in 1998

WANG Likun,TAO Zuyu,YANG Yang,MA Yu,WANG Xu

2000, 36(1):  87-94. 

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By the daily, 5-day, 10-day, monthly and seasonal mean images from hourly GMS-5 infrared images, an analysis of cloud characters of severe storm rainfall during the flood of Yangtze river in 1998 was made. The results show that the mean cloud images disclose the mean features of the severe storm systems. These mean images reveal not only the synoptic cloud systems but also the mesoscale convective cloud cluster. The long-term high water level of mid-Yangtze river and the frequent flood peak of the upper Yangtze river from the middle of June to the middle of August in 1998 was caused by the high frequent activity of convection. The 5-day mean and daily mean images show that the long severe rainfall of Yangtze river was produced by the meso-α scale cloud clusters in the end of July. Additionally, there is somewhat possible correlation between the daily mean cloud image and the daily precipitation. The future research is possibly expected to estimate the flux of water by means of the T_BB of the mean cloud images.

TL Dating: Traces of Ancient Culture in Dongfang Square

ZHENG Gongwang,XIA Zhengkai,REN Xiusheng

2000, 36(1):  128-130. 

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Dongfang Square is situated in Wangfujin area of Beijing. Under the ground lever there is an upper sand layer of river at 10.5m and a lower sand layer of river at 12m. Some fossils, stone artifacts or ashes were found in the layers while digging bases for some buildings. The upper layer age is 15 to 19ka B.P. and the lower layer age is 22 to 26ka B.P. with thermoluminescence dating.

The Numerical Experiments of Aerosol Radiative Effects

DUAN Jianjun,CHEN Shoujun,CHUNG Yongseung

2000, 36(1):  95-101. 

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A simple radiation model was used to calculate daily changes of the aerosol radiative heating rates and cooling rates in different months. Two-stream approximation, hemispheric constant method, adding method and doubling method were applied in the computation. It was demonstrated that in June and December, as far as the daily averaged rates were concerned, whether the aerosol concentration is the heat source or the cold one depends on the aerosol density. However, the relation bears nonlinear features. In the diurnal range, the effects of the aerosol radiative forcing on the atmospheric stability depend on the vertical distribution and density of the aerosol.

Scattering by Dielectric-coated Cylinders Using Fast Multipole Algorithm

ZHANG Yaojiang,CHEN Hongyu,GONG Zhonglin

2000, 36(1):  102-108. 

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A new method, which combines the fast multipole algorithm(FMA) with high order impedance boundary condition(HOIBC), is proposed to analyze the radar cross section(RCS) of dielectric-coated cylinders. Comparing with conventional methods, this combination accelerates the computational speed and decreases the memory requirement. The effectiveness and reliability of the method are verified by numerical results.

On Checking Complexity, Evaluating Complexity and Number of Values for Functions

LIU Tian

2000, 36(1):  109-116. 

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Two families of function classes C∙V and FC are defined and studied in this paper. These classes are defined by limiting the checking complexity of C∙V and the evaluating complexity of FC in C∈{P, UP, FewP, NP}, and by limiting the number of values of C∙V in V∈{SV, PV, MV}. The inclusion and equality relations and the closure properties under function composition operator among these classes are completely decided. These classes not only unify previously known classes of functions but also define new function classes such as Few P∙PV which is a natural function analogue of Few P in that both the domain and checking and evaluating complexity of Few P∙PV are exactly in FewP.

Analysis for Kinetics and Deformation of Porphyroblasts within Ductile Shear Zones and Numerical Modeling in Large Plastic Deformation

LIANG Haihua,LIU Shuwen,SUN Xiaosong,YAN Zhimei

2000, 36(1):  117-123. 

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Numerical modeling for porphroblast's rotation and deformation of augen fabrics in ductile shear zones is done by a large plastic deformation programm based on detailed investigation to three ductile shear zones, Taihangshan Mountains. Some results acquired by computer calculation show that the rigid garnet pophyroblasts can rotate as their matrix flow, and the rotational degree depends on the shear force, ratio of poephroblasts to matrix and the locations of porphyroblasts in the model. Formation of augen fabrics is decided by the ductile deference between the porphyroblast and matrix in deformation rock. Plastic strain first starts from ambient of the porphyroblast, and then develops to rims of porphyroblast and gradually transfers to the centers of porphyroblasts. The brittle remains in the central parts of porphyroblasts come to be decreased through the plastic deformation development, which is accordance with the banding of intensity in many mylonitization zones on wild occurrences and observation in the fabrics of mylonitization rocks under microscope.

Study of Short-chain Carboxylates in Ore-forming Fluids of Gold-bearing Quartz Veins in the Southeastern Guizhou

CAI Junjun,DU Weiwei,ZENG Yishan

2000, 36(1):  124-127. 

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The short-chain carboxylates and inorganic composition of leachates from the fluid inclusions in some quartz vein-type gold deposits in the southeastern Guizhou Province were determined by ion-chromatogrphy. There are some formate, acetate and oxalate in leachates in small amounts, and the content of formate is greater than that of acetate. Homogenization temperatures of fluids inclusions in quartz studied are above 200℃. Monofunctional carboxylates probably are the important components of meso-high temperature ore-forming fluids.

Statistical Modeling of J-effect and Policy Experiments

XIE Zhongjie,LIU Yali,IP Wai-Cheung,WONG Heung

2000, 36(1):  142-148. 

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The main purpose of this paper is to investigate the statistical analysis of J-effect in trade balance of Mexico in 1989-1995. Sparse coefficients modeling has been successfully introduced for the model construction of J-effect. Based on the model, the recovery period index is easy to define and the policy experiment also may be carried out by orthogonal experiment design. The results show that the devaluation of Pesos and the short interest rate are over adjusted but the economic and financial policy during that period were basically correct. Finally, J-effects between Mexico and Japan are compared, it seems that the recovery period of developing countries will be longer than the industry countries.