Table of Content

30 September 1998, Volume 16 Issue 3

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Articles

Theorem of Conservation of the Node Voltage Sensitivity Order and Its Application in Analog Circuit Fault Dictionary

LI FENG, DENG TIEJUN

1998, 16(3):  253-261. 

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Two theorems in linear circuits are presented and proved in this paper. One is the theorem of conservation of the node voltag sensitivity order, the other is the theorem of conservation of node voltage change order. Based on the theorems, a new approach——the hard and soft fault dictionary for analog circuits is presented. Only using one fault characteristic code, this method can determine hard or soft fault which is caused by any element parameter. The size of the dictionary only is half of the size of the former hard fault dectionary.

Unified Model and Analysis of a Class of Adaptive ⅡR Filters

LU ZIYI, YANG LÜ XI, HE ZHENYA

1998, 16(3):  262-268. 

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We present a new approach using vector space base functions to discuss the adaptive ⅡR filter with restricted feedback——Gamma filter and Laguerre filter, and propose a unified model for them. We analyze and compare this class of filters in detail, showing that Gamma filter has advantages over Laguerre filter. We also derive the Wiener-Hopf equation and the corresponding LMS algorithm of them. Some simulation results are also presented.

Bounds for Spectral Radii of Iterative Matrices-

HUANG TINGZHU, BAI ZHONGZHI

1998, 16(3):  269-275. 

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In this paper, we apply the concept of G-functions introduced by Hoffman and Nowosad to obtain the bounds for moduli of eigenvalues of M^-1 N, where M, N∈C^n,n,M is nonsingular. As their applications, we get the bounds for spectral radii of iterative matrices for solving linear systems.

Study on Dynamic Properties of Dispersed Ionic Conductors

PANG QIANJUN

1998, 16(3):  276-284. 

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In this paper, the dynamic properties of dispersed ionic conductors(DIC) are studied. Based on the random -AC-network model of three kinds of conducting bonds, a position-space renormalization method is analytically applied to the calculation of AC conductivity and dielectric response of DIC system. The effect of particle size on dynamic properties of the system is discussed for the first time.

Reliability of the Numerical Solution to the Fredholm Integral Equation of the First Kind

LI CHUNFANG, ZHAO BAOCHANG

1998, 16(3):  285-290. 

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This paper discusses the reliability of the numerical solution to a Fredholm integral equation of the first kind. Although a stable system of linear equations can be obtained from the integral equation of the first kind in the Fabry-Perot inverse interfe rence spectroscopy, by using the simplest rectangle formula, in the case △e=2/x, △x=2/e and the number of equally-spaced sampling points being a suitable odd one, its solution is not the solution to the original integral equation. That is to say, the stable numerical solution is not reliable.

Dependence of Stability of the Hard Domains on the Magnetostatic Interaction between VBLs

TANG GUIDE, LIU YING, SUN HUIYUAN, NIE XIANGFU, LI BOZANG

1998, 16(3):  291-299. 

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The influence of the magnetostatic interaction between vertical Bloch lines (VBLs) on the stability of hard domains in garnet bubble films subjected to a magnetostatic bias field is investigated. The collapse behaviour and the stripe-to-bubble transition behaviour of circular hard domains as well as the relationship between these two behaviour are studied experimentally. The domain wall energy formula of the circular hard doamins is improved by adding a magnetostatic interaction energy term between VBLs. Then, some experimental phemomena of hard domains subjected to a bias field, which have remained unclear for many years, are interpreted qulitatively. Based on these grounds, a method is proposed for estimating the number of VBLs in the walls of hard domains. Finally, the dependence of the hard domain kinds on temperature was interpreted qualitatively by using above improved theory.

Nonlinear Numerical Calculation for Static Permanent Magnetic Circuit

ZHU HONGMEI

1998, 16(3):  300-304. 

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This paper presents a new computing method for the calculation of magnetic circuits consisting of several different magnetic materials including those with hysteresis. The calculated results are in agreement with those by other methods. The optimum design of complicated permanent magnetic circuits can be achieved by using this method.

Analysis of Dielectric Relaxation Characteristics by TSDC in Bioelectret

WANG MAOXIANG, WU ZONGHAN, GAN CHAOQING

1998, 16(3):  305-308. 

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Using pig bone as an example, the dielectric characteristic of bioelectret has been analyzed by the method of TSDC (Thermally Stimulated Depolarization Current). The experiment results showed that there is a strong dielectric effect in animal bones. It is mainly caused by the water molecules bound in gelatin fibers and basal cells and affected by the minor mobile carriers in the bone. Compared the spectrum by computation with that by experiment, the forms of spectrum are similar. It showed that the single frequency relaxation in the bioelectret is mainly caused by the bound water.

Operation Characteristics of LD Pumped Nd:YAG Laser with Fiber Optical Coupling

JIN ZHENHONG, LU JIANG

1998, 16(3):  309-312. 

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The output of a laser-diode array, coupled with optical fiber, is used to an end-pumped Nd:YAG solid -state laser. The continuous output power of 32.5mW is obtained with 13.9% slope efficiency, and the threshold is 22mW.

Electrostatic Analysis of the Newly Fabricated T -Shaped Disk-Edge Field Emitter Arrays

WANG CHEN, ZHAO HONGWEI, YIN HANCHUN, WANG BAOPING, TONG LINSU

1998, 16(3):  313-319. 

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A newly fabricated T-shaped disk-edge field emitter is considered in this paper. Numerical results are presented for a unit cell, consisting of emitter, gate, and anode. A new algorithm, the finite-difference method in a non-orthogonal curvilinear coordinate system (FDM-NOCCS), is used for the calculation of electrostatic field. With the boundary-conforming coordinate lines, this method can deal with microemitter with various shapes efficiently. The dependence of electric field intensity and emitted current upon geometrical factors, the sketch of electron traces and I-V characteristics are presented. Several suggestions are given for the geometry determination of the triode in fabrication.

WGTF Feature-Based Confusing Word Recognition

GU MINGLIANG, WANG TAIJUN, SHI XIAOXING, HE ZHENYA

1998, 16(3):  320-325. 

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This paper presents a novel feature (Weighted Global Time-Frequency feature, i.e WGTF) for confusing word speech recognition, which enhances the difference among different confusing words by selecting proper base fuctions and weighting functions. Meanwhile, the storng discriminative power of artificial neural network has been used as a classifier to further raise the recognition rate. The experiment shows that the proposed method outperforms the standard DHMM and other ANN-based method.

Weights Extraction Method for Adaptive Anti-Jamming Array Processing

LI CHENGYANG, HU GUANGRUI, GONG YAOHUAN

1998, 16(3):  326-330. 

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In this paper, we present a new optimum weights extraction method-Para-llel Ext raction. It is very efficient in adaptive anti-jamming array processing based on QR decomposition least square algorithm. By using this method, it's possible to obtain real-time implementation of the adaptive anti-jamming processing. The formula from "Parallel Extraction" method is discussed in detail. We also provide one kind of its Systolic array implementations.

Analysis and Control of Deadlock for Multi-Resource Share System

XU GUANGYIN

1998, 16(3):  331-337. 

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In this paper, the model of multi-resource share system is built with Petri net. The safety and non-deadlock of the system are discussed. The conditions for deadlock existence are pointed out and the control tools for antideadlock are given. By analysing a practical system, the correctness and viability of our model are examed.

An Improvment of the Strapdown Attitude Algorithm

CHENG JIABIN, ZHANG YANHUA

1998, 16(3):  338-342. 

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This paper develops an strapdown attitude algorithm which has advanteges of less computation expenses and higher accuracy. Implement of the algorithm and simulation results are also given.

The Measuring and Analyzing of the Sn-Pb/Cu Wetting Characteristics

CHANG FALIANG, BIAN XIUFANG, WANG WEIMIN

1998, 16(3):  343-348. 

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This paper has presented the method for studying the Sn-Pb/Cu wetting cha racteristics based on image processing technology and the algorithms for detecting image figures and analyzing the wetting parameters on-line. The measured and analyzed results of the Sn-Pb/Cu wetting characteristics on different direct current have been given.

Preparation of Hydrotalcite and Hydrotalcite-Like Compounds by Microwave Techniques

DU YIBO, HE JING, LI FENG, DAVID G. EVANS, DUAN XUE, WANG ZUOXIN

1998, 16(3):  349-354. 

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Hydrotalcite Mg₆ Al₂(OH) ₁₆ CO₃·4H₂O has been prepared by using both microwave irradiation and conventional heating methods during the ageing process. X-ray diffraction show s that the same materials are obtained in each case, but the microwave process is superior in that a much shorter aging time is required. Mg₄ Al₂(OH) ₁₂[C₁₀ H₆(SO₃) ₂]·4H₂O has been prepared by using microwave and conventional heating methods during the intercalation process. XRD indicates that the sample produced by the microwave method is superior to that produced by conventional heating. Mg₄Al₂(OH) ₁₂(PW₁₂O₄₀) ^2/3·4H₂O has been prepared by microwave methods. XRD and TPDE show that there is a strong interaction between the heteropolyanion and the layers of hydrotalcite.

Investigation of the Dielectric Properties and Characterization of Diamond Film/Alumina Composites

MO YAOWU, XIA YIBEN, XIN JISHENG, HUANG XIAOQIN, WANG HONG

1998, 16(3):  355-359. 

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Diamond films were deposited on Al₂O₃ substrates by microwave plasma chemical vapor deposition (MPCVD) and hot filament chemical vapor deposition (HFCVD) techniques, respectively. The qualities of the deposited films were characterized by scanning electron microscopy(SEM), X ray diffractive spectrometry and Raman scattering spectrometry. The dielectric properties of the diamond film/alumina composites were measured and analyzed as well.

Study on the Properties and Phase Constitution of Cobalt Base Alloy Layer Cladded by Laser on the Carbon Steel Surface

CHEN DAMING, ZHANG HENGHUA

1998, 16(3):  360-365. 

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Cobalt -base alloy layer was cladded on the T8 carbon steel surface by cross-flow-type CO₂ laser with different parameters; the phase constitution, carbide content and chemical composition, microhardness and wear resistance of the alloy layer have been determined by X-ray diffraction, electrolytic extraction, comparison colorimeter and microhardness tester etc. and the saturation of matrix alloy was calculated from lattice constant. It can be concluded that the saturation of r-(CoCr) matrix makes important contribution to the hardness and the wear resistance of the alloy layer, however, is improved greatly due to the M₇C₃ carbide content.

The Influence of the Residual Stress on the Thermal Deformation for the Geometric Figure

HUANG QISHENG, FEI YETAI, HU PENGHAO, HUANG QIANGXIAN

1998, 16(3):  366-371. 

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Mechanical motion produces thermal deformation due to the friction. The thermal deformation depends on the shape, material and the surface residual stress of the element. In this paper we mainly discuss the influence of the surface residual stress on the thermal deformation of a simple geometric figure——a thick long cylinder, and we propose that influence of the thermal deformation can not be neglected in the super precision machining and nanometer technology.

Comparison of the Algorithms on Image Similarity Measure

DONG YUAN, WU XIAOTAO, HU GUANGRUI

1998, 16(3):  372-374. 

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The similarity measure of image could be a useful character in image recognition and compression. Fracal pictures possess similarity and recursion, and fractal dimension naturally becomes a effective measure of similarity. The paper mainly discusses the complexity and applicability of the effective fractal dimension algorithms interested in these years, including blanket method, boxing method, fraction Brown random model method and other methods improved.

An Approach to Output Stability of Two Classes of Uncertain Nonlinear Systems

WANG ZICAI, SHI XIAOPING, CHEN XIAODONG

1998, 16(3):  375-378. 

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This paper mainly deals with the output stability control problem of two classes of uncertain nonlinear systems. The first class of problems is solved through decoupling of uncertain inputs, via partial linearization and poles assignment. The second class is solved through obtaining a direct Lurie's subsystem via partial linearization. The methods provided in this paper can be applied to practice widely and easily.