Table of Content

30 September 1995, Volume 13 Issue 3

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Articles

FOURIER-CHEBYSHEV PSEUDOSPECTRAL APPROXIMATION WITH MIXED FILTERING FOR TWO-DIMENSIONAL VISCOUS INCOMPRESSIBLE FLOW

GUO BENYU, LI JIAN

1995, 13(3):  253-271. 

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A Fourier-Chebyshev pseudospeotral scheme with mixed generalized Boohner fltering technique is proposed for e two-dimensional unsteady vorticity equation.The generalized stability and convergence are proved strictly.The numerical results are presented.The theoretical analysis in this paper provides a framework for error estimations of such mixed approximation.

CHAOS IN PERIODICALLY MISMATCHED NONLINEAR COUPLERS

YIJIANG CHEN

1995, 13(3):  272-282. 

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The existence of chaos in periodically mismatched twin core nonlinear couplers is demonstrated,using the Poincare map as a measure.A physical inteapretation for the mechanism of the onset of the chaos is also presented, based on coupling of the periodio modes of a periodic structure.

FIXED LOCATION COMPLEXITY OF FINITE SEQUENCE

FENG DENGGUO, XIAO GUOZHEN

1995, 13(3):  283-287. 

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A new index to measure local randomness of sequences is presented in this paper;the index can be used to test local stability of sequences.The stability of finite sequence in the statistical view is also analyzed.

STUDY ON FUSE-TAPERED WIDE BAND COUPLER

GU BINGSHENG, ZHANG JIELUN, SHEN WENDA

1995, 13(3):  288-298. 

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The manufacture and theory of a wide band single-mode fibre directional coupler are presented in this paper. Using the different fuse-tapered characteristics of two fibres,we made a two-section quasi-cone-shaped waveguide of unsymmet-rical arms.By means of variational caleulus and the standard theory of eoupledwaves,the coupling behaviors of the waist zone and the trapezoidal zone are ana-lysed;the coupling power of the coupler equals the sum of the coupling powers of these two areas; and the light power of the unsymmetrical arm coupler formed in this way can not be completely transformed between the two fibres.
With proper differences of the characteristics in the fuse-tapered area of the two fibres,the transformation Point of certain power splitting ratio (e,g.,3dB) can be located at the point of extreme value of the ratio against the change of wavelength. In the area near the point,sensitivity of the power change to wave-length is low. Thus a single-mode coupler of wide band is obtained.

AN OPTIMIZABLE CLASS OF QUADRATIC PSEUDO-BOOLEAN FUNCTION

LIU YONGCAI, XU HUIG ANG

1995, 13(3):  299-308. 

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In this paper we give a class of the quadratic pseudo-Boolean function f(x) whose minimum and minimal points can be found in linear time,The basic idea is to transform the graph defined by Q and C in to a combinational circuit of NOT,AND,OR,NAND,NOR,XOR and XNOR gates.The consistent signals in the logic circuit correspond to the minimal points of the quadratic pseudo-Boolean function,This method establishes the construction relationship between the quadratic pseudo-Boolean function and the logic circuit.

APPLICATION OF ERROR CORRECTING CODE IN MOBILE TELECOMMUNICATION

CHEN HUIMIN, CHEN JINGXIN

1995, 13(3):  309-313. 

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The way of utilizing the error correcting code in digital signalling of celluiar mobile telecommunication systems is described in this paper,The decode principle of (63,51) BCH code and its decoder design method of hardware and software are discussed in detail.The software deeode method of truncated BCH code proposed in this paper has the advantages of real time ability,accuracy,reliability and easy realization.It satisfies the requirements of practical use.

A SPEECH RECOGNITION SYSEM BASED ON MHMM AND ANN METHOD

HU GUANGRUI, ZHOU HAO, YAN YONGHONG

1995, 13(3):  314-318. 

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In this paper, we present an improved hidden Markov model (MHMM) method,and propose to incorporate the artificial neural network (ANN) method in the MHMM framework to set up a speech recognition system.We experimentally show that MHMM has been successfully combined with a neural network to build a new system.It is found that the recognition performance of the new system is much better than that of the conventional HMM recognizer. The new system also demonstrates the usefulness of ANN in speech recognition.

DIFFERENCE BOUNDARY ELEMENT METHOD FOR THE FIRST INITIAL BOUNDARY OF NONLINEAR PARABOLIC EQUATION

LU TONGCHAO, YANG DANPING

1995, 13(3):  319-326. 

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In our paper,we establish the difference boundary element method for the first initial boundary problem of the nonlinear parabolic equation.We get not only the integrated theory of the numerieal analysis about our method, but also the optimal prior error estimates.

COMBINATORIAL COUNTING OF BINARY CYCLIC SEQUENCES APPLIEDTOSHARED CONTROLLERS

WANG QIYI, YAN XIREN

1995, 13(3):  327-332. 

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Binary cyclic sequences have been widely used in the research on shared cont-rollers. The point is:that an usable sequence represents a usable scheme of the shared controller, However,to search for all the usable sequences,the old methods have to take all the primitive cyclic sequences as their basic sequences and remove unu-sable sequences from the basic ones.In fact,these basic sequences contain a large number of equivalent sequences and sub-cyclic sequences which are definitely unusable,and removal of these sequences will save considerable amount of calcu-lations.

THE CONFORMAL MAPPING METHOD FOR IRREGULAR CORNER RESISTANCES CALCULATIONS

HAO YUM, CAO WENQING

1995, 13(3):  333-338. 

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Based on conformal mapping,the following relations are deduced in this paper.1.The relation between the number of colner squares of the thin film resis-tances and the ratio of width beside the corners;2.The relation between the equi-valent number of squares of tape resistances whose width can change suddenly and the ratio of the width at its two sides.The calculations agree with the experimental results satisfactorily.

CALCULATION OF FILM THICKNESS DISTRIBUTION PROVIDED BY VACUUM ARC DEPOSITIONWANG

WANG HAO, ZOU JIYAN, YANG LEI, CHENG LICHUN, OUYANG HONHLIN

1995, 13(3):  339-346. 

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Computer caloulation of pure metal film thickness disiribution previded by the Vacuum arc ion boam deposition technique is presented in this paper. For the random arc with a low arc current, a model of single cathode spot with ion beam flux taking into account the cosine function spatial distribution is deduced. For the are steered by an external magnetie field, whieh is parallel to the cathode surface,a multiple cathode spots model is developed. And calculation comparison between the static substrate and rotating substrate is made. Results show that, the film thickness distribution is non-uniform when the are is not controlled and tends to be uniform when the arc is steered by an external parallel magnetic field if the cathode geometry and substrate location are well chosen. Also, film thickness distribntion is more uniform on a rotating substrate then that on a static substrate.Calculation results correspond to the experimental results.

STUDY OF MULTILAYER STRUCTURE USING X-RAY DOUBLE CRYSTAL DIFFRACTION

WU YUNZHONG, XU XUEMING, WANG WEIYUAN, TENG QIN

1995, 13(3):  347-351. 

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The multilayer strncture composed of a glass film, a platinumfilm and an α-Al₂O₃ substrate has been studied by using the technique ofX-ray double crystal diffraction and it is found that different glass materials result in different stresses in the Pt film caused by thermal mismatch within the multilayer materials. The measuring results of the thin film platinum resistor show that the stresses will induce resistance change of the device and different stress status will produce added resistance in different directions. Selecting proper glass materials can make opposite stress in Pt film and opposite anded resistance due to thermal mismatch. The reliability of Pt resistor has been raised with the method of this stress compensation.

PHOTOACOUSTIC LAYERED IMAGING OF DYNAMIC INTEGRATED CIRCUTS

FANG JIANWEN, ZHANG SHUYI, CHENG JIANCHUN, ZHANG ZHONGNING

1995, 13(3):  352-358. 

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The depth profiling of piezoelectric photoacoustic (PA) imaging of the dynamic integrated circuis (IC) has been studied experimentally and theoretically. A one-dimensional model is proposed to study the influence of the external DC electric field on the PA depth profiling and to explain the experimental results. It is found that the PA layered imaging of dynamic IC devices can be used not only to study the subsurface features but also to analyze the working principles and the failure factors of the IC devices.It is demonstrated that PA layered imaging of dynamicIC devices will have important application prospects.

INVESTIGATIONS OF AN INTEGRA TED BACKSIDE CONTACT PRESSURE/PH-ISFET SENSOR

NIU MENGNIAN, LIN WEI, YUAN JING

1995, 13(3):  359-362. 

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A novel backside contact dual pH-ISFET structure with its microreference electrode which can be completely isolated from other sensitive elemcnts and signal conditioning circuits is presented in this paper.Based on the silicon bonding method, silicon micromechanical technique and standard N-well biMOS compatible process,an integrated pressure/pH-ISFET sensor is developed.A highly stsble Chip-Temperature-Constant system is also designed and developed.Measurement prove;the possibility of the new structure and good characteristics of the sensor.

A PREDICTION OF SURFACE WORK-HARDENING DEPTH IN LOW SPEED ORTHOGONAL METAL CUTTING

YANG JICHANG, LIU WEICHENG

1995, 13(3):  363-368. 

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Based on the theory of metal plastic formation,the paper describes the elastio-plastic stress field in the metal cutting deformation zone in great detail.A criterion for predicting the surface work-hardening depth in low speed orthogonal cutting is determined.The numerical solution of surface work-hardening depth is obtained by simulating the machined surface formation process.

THE COHERENT SIGNAL DETECTION OF FM-CW SCATTEROMETER

ZHU WEIZHONG, YU SHUNDI

1995, 13(3):  369-373. 

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The detective method of coherent signals of the microwave coherent polariza-tion scatterometer is proposed.A frequency modulation-continuous wave (FM-CW) is adopted for the scatterometer,The emphases are laid on the generation of coher-ent signals for FM-CW and the detective method of coherent amplitude and phase signals. In the end,the experimental resultsare presented for a newly developed L-B and coherent polarization scatterometer.

PONSINGULARITY AND BOUNDS FOR SOME NUMERICAL CHARACTERS OF MATRICES

HUANG TINZHTU, YOU ZHAOYONG

1995, 13(3):  374-378. 

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In this paper, we study the bounds for some important numerical characters of matrices.One of the results improves the well-known Mirsky inequality. The other results are better than the well-known Ky Fan-Hoffman inequality,Hada-mard inequality and Johnson-Newman inequality respectively in many cases. A criterion for the nonsingularity, and a sufficient condition for M-matrices andP-matrices is obtained.