Table of Content

30 June 1993, Volume 11 Issue 2

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Articles

RECONSTRUCTION OF THE PERMITTIVITY PROFILE OF ONE-DIMENSIONAL GRADUALLY CHANGED MEDIUM BY USING AN EQUIVALENT NETWORK TECHNIQUE

CUI TIEJUN, LIANG OHANGHONG

1993, 11(2):  95-103. 

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In this paper, a general relation between the reflection coefficient and the permittivity is derived by using an equivalent network technique. By simple transform, a novel approximate analytic solution for reconstructing the permittivity profile is obtained, which is more generalized than the former relation[2,3].

INFLUENCE OF ADDITIVES ON GAS SENSITIVE CHARACTER OF TIN OXIDES

ZHU WENHUI, XU JIAQIANG, YAN KEQIU

1993, 11(2):  104-108. 

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In this paper, chemical co-precipitation and impregnation are adopted to make gas sensitive, SnO₂ by doping it with 15 additives. The structure and component of the materials are then studied with TEM, XED and XPS, and the gas sensitive character ia tested by means of static state. Results show that SnO₂ doped with Ag, CuO and ZnO, which are cheap, can be used to make inflammable gas sensors; that the doping of ZnO and Re₂O₃ can improve the alcohol selectivity of SnO₂; that Sb₂O₃ markedly reduces the electrical resistance of SnO₂; and that there exist phase reactions between the addtives Ag, CeO₂ and the material SnO₂, thus influencing the binding energy of Sn3d.

SCALING CALCULATION FOR RCS OF LOSSY TARGETS FURTHER DISCUSSION ON THE SIMILARITY OF LOSSY ELEOTEOMAGNETIO SYSTEMS

SHI ZHENDONG, YANG SHIWEN, DING CHUNSHENG

1993, 11(2):  109-114. 

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In this paper, the theory of similarity and dimensional analysis are used for the scaling measurements of EOS of lossy targets'. Scaling calculation formulas between the prototype and models have been derived. By means of these formulas, the EOS of the prototype can be inferred precisely from the measured values of models, even though they do not meet the condition of physical similarity.

HIGH-BIREFRINGENCE-FIBER POLARIZATION COUPLER

JIN ZHBNHONG, HUANG ZHAOMING, XIAO WBINIAN

1993, 11(2):  115-118. 

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In this paper, we present a new polarization coupler using high-birefringence-fiber. This kind of device previously reported was based on the application of mechanical force on a comb-like plate. We made this device by using the PZT material, so the coupling strength can be controlled by an electrical signal. The device is easy to use and very good waveform has been obtained.

A NEW PARAMETER FOR THE CHARACTERIZATION OF POWDER SURFACE

WANG PING, GUO HONGYOTJ, SONG LANHUA, HUANG YULI

1993, 11(2):  119-124. 

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A new parameter, ATRHL (adhesion tension ratio of hydrophilic liquid to lipophilic liquid in contact with powder) used for the characterization of powder surface has been put forward. The measurement of ATEHL for powder is based on the adhesion tension of distilled water and toluene in contact with powder. Thus ATKHL expresses the hydropilic-lipophilic degree of the powder surface.

FORMATION OF pn JUNCTION WITH CoSi₂ CONTACT BY SOLID STATE INTERACTION OF Co WITH DOPED Si AND ASENIC BEHAVIOR DURING THE INTERACTION

LIU PING, LI BINGZONG, JIANG GUOBAO, HUANG WEINING, GU ZHIGUANG

1993, 11(2):  125-130. 

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This work studied the technology of formation of pn junction and self-aligned CoSi₂ film contact on Si doped with B P As by diffusion or ion implantaion. Ion beam sputtering was applied for Co film deposition, and solid state interaction of Co/Si was performed by rapid thermal process (RTF) to form CoSi₂ films. The sheet resistances of doped Si regions decreased by an order of magnitude after CoSi₂ formation. For the samples implanted with As, the effects of different thermal processes on As redistribution during interaction of Oo/Si were investigated. Experimental results indicated that in the case of conventional process (As was activated prior to CoSi₂ formation), a snowplow effect of As during interaction of Co/Si was observed. In the case of concurrent process (As activation and interaction of Co/Si were carried out in one step), As exibited an obviously different behavior. The spreading resistance probe and electrical characterization showed that, for either of the above two cases, a high.carrier concentration can be produced at the interface of CoSi₂/Si, and the pn junctions with CoSi₂ contact exibited good I-V properties, and their leakage current was much less than that of the comparative pn. junction with Al/Si contact.

DETERMINATION OF THE PULSE WIDTH OF PULSED MAGNETIZING FIELD FOR A RARE EARTH MAGNET WITH HIGH COERCIVE FORCE

FU ZHIYU, XU MEIJIE

1993, 11(2):  131-135. 

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An effective device which can generate the pulsed magnetizing field is shown. The approximate expression for the pulsed magnetizing field is derived, and its pulse width and peak intensity related to the circuit elements are given. A reasonable physical model which describes the magnetization process and involves the magnetic hysteresis and eddy current is presented, and the numerical computation is made. The pulse field widths which are required to magnetize the specific magnets are determined, and the useful design parameters are obtained.

THICKNESS DISTRIBUTION OF THIN FILM DEPOSITED WITH MAGNETRO-SPUTTERING

FAN ZHENGXIU, XUE SONGSHENG, HE ZHAOLING

1993, 11(2):  136-140. 

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Thickness distribution of thin films deposited with magnetro-sputtering is studied in this paper. Theoretical analysis tand value calculation are conducted under three conditions when the substrate is fixed; when the substrate is rotating; and both the substrate and the workshelf are rotating. It is shown that the distribution mainly depends on the highness of the substrate. Very uniform thin film is deposited on the substrate by adjusting the highness of the substrate and and distance between the target and the rotating center, as proved by experiments.

AN APPROACH TO THE ASYMPTOTIC SOLUTION OF OSCILLATORY TAIL OF REFLECTIVE INITIAL VALUE PROBLEM OF KdV EQUATION

ZHOU GUANGHUI

1993, 11(2):  141-146. 

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Assume that the solution of KdV reflective initial value problem equals the sum of the pure-soliton part and the non-soliton part, and the latter is comparatively small. Then the equation satisfied by the non-soliton part is linearized and the solution of asymptotic oscillation form is obtained directly by means of Fourier Transformation. After solving the discrete spectrum of the time-independent Schodinger equation associated with the initial value by some proper method, the pure-soliton expression is available according to 1ST. Through the calculation of specific initial value examples, the results obtained in this paper are found to be consistent with those of the references.

THE RELATION AMONG THE RATE OF PROFIT, RATE OF PUMPING HEAT AND COEFFICIENT OF PERFORMANCE OF A THREE-HEAT-SOURCE HEAT PUMP

YAN ZIJUN, CHBN JINCAN

1993, 11(2):  147-151. 

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A general relation among the rate of profit, rate of pumping heat and coefficient of performance of a three-heat-source heat pump is given in this paper. By using it, the relation between the optimal rate of profit and coefficient of performance of an endoreversible three-heat-source heat pump is derived and the optimal criterion of the coefficient of performance is discussed. The conclusions obtained have a certain instructive meaning for the optimal design and the performance improvement of a class of three-heat-source heat pumps such as absorption heat pumps, chemical heat pumps, and so on.

STUDY AND IMPLEMENTATION OF A BROADBAND COMMUNICATION SUB-NETWORK IN ACCORDANCE WITH MAP

ZHANG ZHENCHUAN, WANG YUBXIAN, WANG GUANGXINO

1993, 11(2):  152-158. 

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A broadband network designed in accordance with MAP is considered to be indispensable for the computer integrated manufacturing system (CIMS) in automated factories. So the research and development of its protocols, software, and hardware are very much emphasized. In this paper, a broadband communication sub-network implemented in accordance with MAP is introduced. It mainly consists of three lower layers, the physical, data link and network layers of the ISO/OSI Eeference Model. The data transfer experiment in the communication Sub-network has been successfully done in our laboratory.

THE COMPUTER QUANTITATIVE ANALYSIS OF SOIL MICROSTRUCTURE

ZHANG DIANCHENG, YANG JINGAN, LI YUN, LING ZEMIN

1993, 11(2):  159-165. 

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This paper proposes an algorithm of image segmentation based on pattern classification according to the features of soil microphotographs. The algorithm can overcome the influence of holes in the soil particles on extracting the parameters. Finally, a new general tracking boundary method is used to acquire the quantitative parameters of the soil particles. The methods and techniques presented in this paper are very useful for studying the properties of the soil particles under variance and destruction of particle shapes caused by forces.

A METHOD TO FORM a-Si:H/a-SiC:H MULTILAYER AMORPHOUS FILM WITH LASER CVD AND THE RESEARCH OF ITS OPTICAL CHAR ACTERISTICS

WU DINGXIANG

1993, 11(2):  166-170. 

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This paper introduces a method of analysing gas by photochemical reaction of laser to form an α-SiH/α-SiC:H multilayer structure amorphous film, and discusses its optical characteristics measured with XPS and other means.

THE PARAMETER VIBRATION EXCITED BY NON-LINEAR ELECTRO-MAGNETIC FORCES IN A LOW-SPEED A.C.MOTOR

QIU JIAJUN

1993, 11(2):  171-179. 

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A unified mathematical system is suggested for relating the rotor non-linear vibration equation of a low-speed multipolar A. C. motor with the steady-state three-phase nonsymmetric circut equation. The first order approximate solution is obtained. Curves for the amplitude characteristic, the transient process through the zone of resonance, and the process in the starting vibration of the parameter resonance are computed. Experimental research is carried out and results are shown to be in good agreement with the theoretical results, thus revealing the rules of this vibration.

Research Notes

DYNAMICAL DETERMINATION OF SMOKE CONCENTRATION BY SCATTER LIGHT AND THE MODEL USED

LIU KUOWEI, MAO JINGYING, ZONG OHUNYING, WANG ZHIZHENG

1993, 11(2):  180-183. 

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In this paper, the relative concentration of smoke in the dynamical atate is determined by means of scatter light. Experiments demonstrate that scatter light is increased with the increase of smoke concentration in a given scale; that scatter light has to do with its wavelength, there being an optimal scatter light wavelength; and that with the change of Smoke concentration, scatter light manifests three character regions. Upon this, a model is suggested for the float system consisting of large particles of smoke. The three character regions can be explained by means of this model qualitatively.

PRACTICAL ALGORITHMS FOR DISTINGUISHING ISOSPECTRAL MOLECULES

ZHANG ZHINAN, LIU YUTING, ZHU WEIBAO, CHEN QIAN, DONG DATING, ZHANG JIANKANG

1993, 11(2):  184-188. 

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How to practise a kind of exact algorithm for obtaining the characteristic polynomial of a 0-1 matrix, particularly a Hucker matrix, is presented in this paper.