Table of Content

30 June 1992, Volume 10 Issue 2

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Articles

GROWTH OF TITANIUM NITRIDE FILMS BY DYNAMIC ION BEAM MIXING AND INVESTIGATION OF THEIR PROPERTIES

WANG XI, LIU XIANGHUAI, ZHENG ZHIHONG, HUANG WEI, ZOU SHICHANG

1992, 10(2):  95-100. 

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Titanium nitride films were prepared by simultaneous vacuum deposition of titanium and nitrogen ion beam bombardment with an ion energy of 40 KeV.RBS analysis showed that nitrogen ion bombardment could clearly reduce the oxygen concentration in the film. At the same atomio arrival ratio, the component ratio (N/Ti) in the films decreased with the increase of titanium deposition rate or sample temperature. This fact was considered to have arisen from the situation that the film composition was strongly affected by the adsorption of nitrogen. The films wore mainly TiN polyorystale. The preferred crystalline orientation of the film changed from <111> to <200> with the increase of the atomic arrival ratio (N/Ti). The titanium nitride films formed by dynamic ion beam mixing exhibited good and tear resistance and strong adhesion to the substrate.

PYROELECTRIC EFFECT IN LIQUID CRYSTAL LANGMUIR-BLODGETT FILMS

FANG JIYU, WEI YU, SUN ZHENQMIN

1992, 10(2):  101-105. 

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The noncentrosymmetric liquid crystal LB films were prepared by the horizontal lifting method. Optical absorption spectra and morphological observation showed that aggregates of liquid crystal molecules were formed in the LB films. In order to observe the pyroeleotrio effect in the polar LB films, the Al LB film Al structure was fabricated. The static pyroeleotrio coefficient was of the order of 10^-11.cm^-2·K^-1. The influence of the change of the LB film structure on the pyroeleotrio coefficient was discussed based on the experimental results.

COMPLEX RAY FIELD IN LOSSY MEDIA

RUAN YINGZHENG, DU HUIPING

1992, 10(2):  106-112. 

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As an asymptotic solution of the wave equation at high, frequency, the complex ray field in lossy media is discussed in detail, and oompai'ed with the case of lossless ones. From these discussions, it is found that the Gaussian beam can also be effectively expressed by the complex ray field in lossy media, and the complex ray approaches developed in the lossless case can also be used in the lossy case. As an example, we give the ROS results obtained by both theoretical and experimental methods for a conducting flat plate with one surface coated with radar absorbing materials. Their good agreement shows the extension of complex rays from lossless media to lossy ones is reasonable.

VARIATIONAL SOLUTION OF RESONANT CAVITY FILLING ANISOTROPIC PLASMA

LIU KAI, ZHANG WENXUN, YING JIMIN

1992, 10(2):  113-120. 

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In this paper, a universal variational equation for solving electromagnetic boundary problems is deduced from Maxwell's equations. It has the advantage that the trial functions are not restricted by the boundary condition. So it is especially useful in solving problems of anisotropio medium of irregular geometry. The resonant characteristics of plasma-filled cavities are analysed by using the Rayleigh-Ritz method. The numerical results in the case of rectangular cavity are in agreement with those from reference^[3]. Besides, the resonant frequencies and Q values of quasi-TEm and quasi-TM₀₁₁ modes are calculated as the functions of plasma parameters, which are of value in the industrial applications of plasmas.

NON-INVASIVE TECHNIQUE FOR DETECTION OF SHBE AND ITS EVALUATION FOR CLINICAL APPLICATION

WANG BAOHUA

1992, 10(2):  121-127. 

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The methods of surface detection of His bundle activity can be generally divided into two kinds. One method uses the technique of serial signal averaging which requires digital averaging of 50-100 sequential cardiac cycles. But it can not record the His bundle signal on a beat-by-beat basis and so it is not effective in clinical applications in that some diseases such as arrhythmia, AV block and less-then-oonstant RR intervals ooour intermittently instead of in every cardiac cycle. The other method can avoid the disad ventages of serial signal averaging by using multiple parallel inputs with amplifications.
The real-time detection of the His bundle activity on a beat-by-beat basis can be achieved. Because of this advantage, the latter method deserves much attention.This paper describes the study of the His bundle activity detection based on the parallel averaging technique in the institute of BME of SUST, and its evaluation for clinical applications.

EFFECTS OF INTERP ARTICLE INTERFERENCE IN SMALL-ANGLE X-RAY SCATTERING

GUO OHANGLIN

1992, 10(2):  128-136. 

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According to the small-angle X-ray scattering theory, it is always assumed that the scattering intensities of particles are simply added up to give the total diffraction pattern. This is true only for a very dilute particle system. However, with increasing concentration, some effects of interpartiole interference should be expected. Several models and theories of interpartiole interference have been presented but no rigorous solution can be given so far. In the practical case, the magnitude of the concentration effects can be seen by plotting the scattering curves of the various concentrated particle systems, normalized to unit concentration. Sometimes it is impossible to measure a series of concentrations in the applications of materials science, such as determining the size distribution of a mioro-inhomogeneous region, global droplets of spinodal decomposition, precipitation of the second phase, condensation of vacancies and defects in bulk materials. Therefore, it is of importance to find an empii-ical equation of the interference function. The intensities of ultrafine MoSs samples in several concentrations at different angles are determined in detail. The empirical equation of the interference Junction is deduced as:K^-1=[1+2.5ω^1.4+2θ° (15.4ω^0.5-23.6ω²-1.3ω^0.01)]^-1.

THE TEMPERATURE EFFECT OF NiCr-NiCu THERMOCOUPLE UNDER PRESSURE

HUANG TONGKAI, GU JINMO, CH. SAJJAD AHMAD, JIN BIANJUN

1992, 10(2):  137-140. 

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The pressure effect on the NiGr-NiCu thermocouple was measured at room and liquid nitrogen temperatures up to 20 kilobar. The results showed that the pressure effect on the thermo-emf of this thermocouple was enhanced by the pressure. From 0 to 20 kilobar and in the accuracy of 0.1 Kelvin the pressuer effect on the thermo-emf did not affect the temperature measurement.

ROSIM ROBOT SIMULATION SYSTEM AND ITS APPLICATION

DENG JIANYI, ZHANG ZONGMINO

1992, 10(2):  141-147. 

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With the increasing speed of the computer and its graphic development, CAD status is more and more outstanding in robot research. A number of studies and software of OAD are presented annually. These achievements have played an important role in robot research, design and so on.
This paper deals with a robot simulation system EOSIM that runs on the miorooomputer. The system is not only a digital simulation, but also a 3D graphic one. The application of the software is divided into two levels to meet different needs. The design outline and structure about the simulation system and some typical examples are presented.

AN UPPER-BOUND THEORETICAL SOLUTION TO STRIP ROLLING

ZHAO DEWEN, LI GUI

1992, 10(2):  148-154. 

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The two-dimensional velocity and strain rate fields which are different from Avitzur's have been deduced in this paper. An analytical upper-bound power to strip rolling has been obtained by using the integral as a function of the upper limit and the integration which depends on a, parameter without any mathematical ^simplification. The solution is compared with Avitzur's cylindrical coordinate solution.

APPLICATION OF PATTERN CLASSIFIED MAPPING TO MODELING IN INDUSTRIAL OPTIMIZATION

LIXJ MIAOXIU, CHBNG ZHAONIAN

1992, 10(2):  155-160. 

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In tkis paper the pattern classified mapping is applied to modeling technological processes in industrial optimization. A numerical example of carbonization process in an aluminium-making plant indicates that the PRESS (Prediction Error Sum of Squares) of the model from our method is lower than that from conventional regressions, and the predictor derived from the present work is more robust.

GROWTH OF Zn_1-xMn_xSe FILMS BY HOT WALL EPITAXY ON GaAs SUBSTRATE

WANG JIE, LU HONGQIANG, SHEN JUN, LI ZHESHEN, WANG JIANBAO, SHEN XIAOLIANG

1992, 10(2):  161-166. 

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Zn_1-xMn_xSe films are grown on the (100) GaAs substrate by hot wall epitaxy. The films are studied by X-ray diffraction, Raman and AES. The results show thai Single crystal (100) Zn_1-xMn_xSe films have been gotten and that x can be up to 0.17.

A NEW MODEL FOR THE MECHANISM OF SILICON BIAS-DEPENDENT ETCHING AND HEAUILY DOPED ETCH-STOP

LIN HAIAN, ZHANG JIAWEI, CHEN JIAN

1992, 10(2):  167-173. 

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In this paper, the dependence of anisotropic silicon etching on bias-voltage and the influence of heavy doping are studied in detail. Two models of liquid-semiconductor contact energy band and transport of interface changes are set up. The concept of reaction implantation is put forward. Meanwhile, it is considered that the etching rate usually depends on the filling conditions of the interface state. The relations of experimental etching rate and bias-voltage are explained correctly. Finally, after considering the recombination of disequilibrium carriers, the etching rate carrier concentration formula is found to be in good agreement with experimental data.

THE CHARGE STORAGE AND TRANSPORT OF POLYTETRAFLUOROETHYLENE (PTFE) ELECTRET

XIA ZHONGPU

1992, 10(2):  174-180. 

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In this paper, the influence of heat-treatment on charge storage capability and the outstanding charge storage capability at elevated temperature for the PTFE electret were studied by means of constant voltage corona charging at RT and elevated temperature and the TSD experiment. The transport model of detrapping carriers of the PTFE electret which shifted towards the back electrode of the sample was investigated by means of the heat pulse technique, and the LIPP method in combination with the TSD experiment.

Research Notes

THE TEMPERATURE DEPENDENCE OF THE TWO-DIMENSIONAL FRENKEL EXCITON EFFECTIVE MASS

WANG ZONGGANG, GIT SHIWEI

1992, 10(2):  181-183. 

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The properties of a two-dimensional Frenkel exoiton is discussed by means of a model which takes account of the atomicity of the lattice. The lattice vibration and the interaction between the exciton and the lattice displacement are treated by the second quantization method. The self-trapped energy and the temperature dependence of the effective mass of the two-dimensional Frenkel exoiton are derived.

GLOBAL ASYMPTOTIC STABILITY OF LARGE-SCALE NONLINEAR SYSTEMS WITH INFINITE DELAYS

DENG FEIQI, ZHAO YUPENG

1992, 10(2):  184-188. 

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In this paper, we discuss the global asymptotic stability of large-scale nonlinear systems with infinite delays by the Liapunov Function Method and some new skills. We have obtained some simple and direct criteria for the stability of the systems.