Table of Content

31 March 1994, Volume 12 Issue 1

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Articles

THE FOURIER PSEUDOSPECIRAL METHOD FOR FLUID FLOW WITH LOW MACH NUMBER

ABDUR RASHID, CAO WEIMING, GUO BENYU

1994, 12(1):  1-12. 

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A Fourier pseudospectral scheme with a restraint operator is developed for solving fluid flow with low Mach number.The generalized stability and convergence are proved.Numerical results are presented also.

A NEW METHOD TO CALCULATE THE VIBRATIONAL DENSITY OF THE AMORPHOUS STATE Inverse Matrix Equation of Motion Method

GAO ERZHEN, GU SHIWEI

1994, 12(1):  13-17. 

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On the basis of the equation of the motion method,a new method to calculate the vibrational density of the amorphous state:the inverse matrix equation of motion method is developed.This method is more precise and faster than the old one.

ANALYSIS OF THE ELECTROMAGNETIC SCATTERING CHARACTERISTICS FROM AN FSS WITH MULTILAYERED DIELECTRIC SUBSTRATE BY THE METHOD OF LINES

HONG WEI

1994, 12(1):  18-24. 

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Based upon Floquet's theorem,the method of lines is first applied to the analysis of electromagnetic scattering characteristics from a frequency selective surface (FSS) with multilayered dielectric substrates. The formulation is suitable to the FSS with arbitrarily-Shaped elements. Numerical results are in agreement with the experimental data,which verifies the validity of this technique.

THE EIGEN PERMEABILITY AND EIGEN WAVE IN UNRECIPROCAL MEDIUM

LIANG CHANGHONG, CUI TIEJUN, LI RUNQI

1994, 12(1):  25-31. 

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The eigen permeabilities and eigen waves of the basic transmission modes are deduced,which play intrinsical roles in the propagation of plane waves in an unreciprocal medium. The eigen permeability correspond to the propagation coefficient of eigen waves,and all transmission modes can be considered as the linear combinations of these eigen waves.It is also demonstrated that the eigen wave is of ellipfical polarizati in general.

COMPUTATION OF EM SCATTERING FROM 2-D ASYMMETRICALLY ANISOTROPIC CYLINDRICAL MEDIUM BY USING BOUNDARY ELEMENT METHOD

ZHANG MING, ZHANG WENXUN

1994, 12(1):  32-40. 

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In this paper,the electrical field boundary integral equations for the arbitrary shaped two-dimensional homogeneous asymmetrically anisotropic cylindrical medium are derived based on Green's theorem. On applying the pulse-function expansion and,the point-matching technique,the integral equations can be converted into liner algobraical equations.The monostatic and bistatc radar cross sections of asymmetrically anisotropic circular,square and trianglar cylinders are calculated.

THE CRITERIA OF FINITE TIME THERMODYNAMICS ON THE PARAMETER SELECTION OF A HEAT ENGINE OPERATING BETWEEN TWO FINITE HEAT SOURCES

YAN ZIJUN, CHEN JINCWN

1994, 12(1):  41-45. 

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The fundamental optimum formula,the relation between the maximum power output and efficiency,of a heat engine operating between two finite heat sourecs and the criteria of finite time thermodynamics on the parameter selection of the engine are derived.Moreoyer, some wrong conclusions in the related literature are pointed out.

MOMENT EXCITER AND ITS APPLICATION TO EXPERIMENTS OF STRUCTURE-BORNE SOUND

QIU SHUYE, B. M. GIBBS

1994, 12(1):  46-52. 

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In this paper the performances of the moment exciter which is composed of two magnetostrictive rods (Tb_0.3Dy_0.7Fe_1.95) have been discussed.Both simple theory and experiments indicate that the performances of the moment exciter do not basically influence the measurement results of the moment mobilities, but do affect the efficiency for exciting the rotation. The efficiency for exciting the rotation has also been calculated in this paper.

MERCURY SENSOR WITH BI-WAFER OF PIEZOELECTRIC CRUSTAL

LI GUANGYUN, LU XINGEN, WANG KEFENG, DU GENDI

1994, 12(1):  53-56. 

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A new type of piezoelectric crystal sensor detector is designed. The reference wafer and the sensitive wafer are in touch with the detected gases directly at the same time. The mercury vapor response and the interference influence of moisture are tested using the piezoelectric crystal mercury sensor with a double wafer.Results show that in a wide range mercury vapor detection is not influenced by the sensor,when the reference wafer touches the detected gases. Moreover the interference of moisture or any other gas can be greatly decreased.

ON THE STABILITY OF TIME-VARYING INTERVAL MATRIX

SUN JITAO

1994, 12(1):  57-60. 

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In this paper,we suggest the stability concept for the time-varying interval matrix and have obtained sufficient conditions of stability of the time-varying interval matrix. As an example,the results in paper[1] are extended and improved.

SEPARATION AND PROPERTY OF ISOMERS OF α-PINENE-MALEIC ANHYDE ADDUCT

GAO NAN, PAN PENGCHEN, YU WEN

1994, 12(1):  61-66. 

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The separation of isomers of α-pinene-maleic anhydride adduct was studied.The high pure samples of α-terpinene-maleic anhydride (3) and dipentene-maleic anhydride (6) were obtained.The solvability,the activity of cyclic anhydride and the thermostability of (3) were investigated by comparing with those of (6).

NEW Q-ENHANCED SALLEN-KEY'S SC LOWPASS FILTER

WU JIE

1994, 12(1):  67-72. 

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A new Q-enhanced SC second order lowpass filter is presented.The circuit is derived from the Sallen-Key's active RC circuit with a unity-gain amplifier. The optimal design of the minimun capacitor spread for the circuits proposed.Pole ω₀ and pole Q sensitivities as well as gain-bandwidth product effects of the SC circuit are also investigated.Computation shows that the capacitor spread for the proposed circuit can be significantly reduced.The validity for the circuit is verified by the experiment with discrete elements.

MICROSTRIP HIGH VOLTAGE SHAPED PULSE GENERATOR

WU KEQIN, CHEN SHILING, BAO JIASHAN, ZHI TINGTING, CHEN LANRONG, GU GUANGQING

1994, 12(1):  73-77. 

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In this paper,the design of the microstrip high voltage shaped pulse generator is described and an integrated system with the high voltage shaped laser pulse generator and the Pockels cell is developed.

FAST SEPARATION ALGORITHM OF BI-LEVEL IMAGES SUPERIMPOSED ON HALFTONE IMAGES

YANG JINGAN

1994, 12(1):  78-82. 

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This paper proposes a fast separation algorithm of bi-level images superimposed on halftone images.The technique used in the algorithm can separate bi-level images superimposed on halftone images correctly.Therefore it can be used to process and analyse facsimile effectively.

THE POSSIBILITY OF IMPROVEMENT IN PERORMANCE OF DIFFUSED JUNCTION SILICON SOLAR CELLS BY MAKING DEEPER DIFFUSION AND ETCHING THE SURFACE

ZHANG XIUMIAO

1994, 12(1):  83-87. 

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Assuming the diffused impurity profile to be Gaussian,a resolution of the minority carrier continuity equation for the diffused region thinned by etching the surface has been given. On the basis of that, computations and analyses have been made for some practical examples. It has been shown that in order to increase the short circuit current contributed by the n⁺ diffused region, besides the lower surface recombination velocity and lower built-in field gradient,the higher built in field itseif is also important.In the present work it has also been shown that making deeper diffusion and etching the surface are effective to increase short circuit current contributed by the n⁺ diffused region only if the deeper diffusion is made together with the higher surface impurity concentration.

STUDY OF OPTIMAL PROCESSING FORXH-REP-2 POSITIVE ELECTRON-BEA MRESISTS

WANG GUOQUAN, LOU TENGJIAO, WANG QINMEI, WU YULI

1994, 12(1):  88-91. 

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This paper describes briefly the principle and characteristics of electron-beam lithography.The mechanism of the interaction of energetic electrons with resist materials is also described.The whole processing of XH-REP-2 positive electronbcam resists discussed in detail. We have found a group of optimal parameters of XH-REP-2 positive electron-beam resists and come to the conclusion that XH-REP-2 positive electron-beam resists have high resolution and sensitivity.

STUDY ON THE APPLICATIONS OF RING-SULFONATED POLYANILINE

ZHANG GUIPING, GONG KECHENG

1994, 12(1):  92-94. 

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The potential applications of ring-sulfonated polyaniline (SPANI) have been studied.A kind of easily-made SPANI/PVA composite film has developed and its potential applications are pointed out.The results show that SPANI has the advantages over PANI in elecotrochemical activity and in the application of the battery with zine used as the negative electrode.