Table of Content

31 December 1985, Volume 3 Issue 4

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Articles

THEORY AND COMPUTATIONS FOR 3-DIMENSIONAL MULTI-CRACK PROBLEMS——(I) THEORETICAL ANALYSIS AND GENERAL FORMULATIONS

OUYANG GHANG, XU LINLIN

1985, 3(4):  283-299. 

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In this paper, a semi-analytical method to solve the 3-dimensional problems of parallel multi-crack in an infinite elastic solid under remote uniaxial extension is proposed. Through introducing equivalent loads along crack surfaces and by using expansions of local coordinates, the problems are reduced to a set of Fredholm integral equations and thus a set of linear algebraic equations are obtained by series expansions. The solutions of this set of linear algebraic equat ions give the required answers of the crack problems discussed.
The paper is in two parts. Part (Ⅰ) here is for the theoretical analysis and general formulations. Numerical computations and examples are given in Part (Ⅱ).

NOTES ON FITTING PROBABILITY DENSITY FUNCTIONS IN RELIABILITY ENGINEERING

MI JIE, FAN WEIMIN

1985, 3(4):  300-305. 

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In engineering the density functions of normal, gamma and beta distributions are often used to fit other pdf f(x). The way to do it is to determine the two parameters in those distributions mentioned above by the first two moments. From the fact that the eigenfunctions of Sturm-Liouville equation form complete orthogonal series, it is shown here that the method usually used just makes the first two generalized Fourier coefficients of the orthogonal expansion of f(x) with respect to the orthogonal series equal to zero.

THE NUMERICAL SOLUTION OF THE FIRST-KIND FREDHOLM INTEGRAL EQUATIONS

LI MINGZHONQ

1985, 3(4):  306-312. 

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In this poper, we study the numerical solution of the first-kind Fredholm integral equation
∫_-1¹ k(t,s)y(s)ds=f(t),t∈[-1,1]
where f(t) is continuous and k(t, s) may be weakly singular. The kernel k(t, s) is assumed to be expressed as k(t, s)=h(t, s)m(t, s), where h(t, s) is of a standard form for example h(t, s)=|t-s|^α, α>-1, and m(t, s) is continuous. By using Lagrange polynomial interpolation, a sequence of the approximate solution is established and the convergence is proved.

STATISTICAL TESTING FOR SEQUENTIAL CIRCUITS

DOU RUJING

1985, 3(4):  313-317. 

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The statistical testing presented in this paper is an improved compact testing method for sequential circuits. The method tests circuits using ‘acceptance region’. The background for the theory on ‘acceptance region’ and practical computational method are given in this paper.

AN X-BAND GROUND-BASED SCATTEROMETER

ZHU WEIZHONG, YU SHUNDI, XU SAIQING

1985, 3(4):  318-325. 

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This article describes design construction and characterization of a transistorized X-band ground-based scatterometer. A FM-CW system is adopted. Two antennas transmitter and receiver are parellally mounted on the top of a crane boom(8 to 12 meters above the ground). The measurement of backscattering coefficients σ⁰ can be obtained with four states of polarizations (HH, VV, VH and HV) in the range of azimuth angles 0~330° and elevation angles 0~85°. The system consists of RF assembly and a control box, with a multiple-core between them.

DIFFRACTION THEORY OF OPEN CAVITIES OF THE CIRCULAR AND COAXIAL WAVEGUIDE TYPE

ZHU JINLIN

1985, 3(4):  326-335. 

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For open cavities with slowly varying cross-section the reflective coefficient of diffraction under general nnsymmetrical mode, when "a phase correction factor" is introduced, can be found by use of the method of transverse-section. Parameters of the open cavities are found under resonant conditions of longitudinal wavenumber. The method described can be used to solve multi-mode problems. Several different types of open cavities are studied, and it is concluded that coaxial open cavity with varying section has the most sparse eigen spectrum. In this paper, method of engineering design is briefly discussed.

PRECISION LOW FREQUENCY PHASE CALIBRATION STANDARD

LO WEIDA, HU XINGUO, CHENG GUEIFAN

1985, 3(4):  336-340. 

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A new high-precision low frequency phase calibration standard has been developed by using a technique of phase error demultiplication. The frequency range is from 20 Hz to 100 kHz (discrete frequency). The phase shift is from 0 to (n×360) degrees, where n is an integer. Theresolution is (3×10^-8×F) degrees, where F is in hertz. The accuracy is ±(1×10×F±0.001) degrees. The distortion is better than 1×10^-5/10min.

THE ROLE PLAYED BY GR IN ⁸⁷Sr(n,n')^87mSr INELASTIC SCATTERING

XIE KUANZHENG, ZHOU SHENGMO, YAN QLNGQUAN, CHEN XUESHI, ZHOU MUYAO, ZHANG YONGFA, ZHANG LU, CHEN YITAI, WANG CHUANSHAN

1985, 3(4):  341-348. 

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The theoricians^[1] have found that the virtual excitation of GR plays an important role in ⁸⁷Sr(n, n')^87mSr inelastic scattering, the target with a hole in a neutron close shell, even when the incident neutron energy is around 3 MeV. The cross section of ⁸⁷Sr (n, n')^87mSr((9⁺)/2→(1-)/2) has been calculated for compound nucleus'with H-F formula, for GR'S with phenomenological as well as microscopical method, hut there are no experimental data that could compare with them directly yet.

A STUDY OF Cu₂S/CdS SOLAR CELL BY AES

YU ZHIZHONG, HUANG FANLONG

1985, 3(4):  349-354. 

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The solar cell of Cu₂S chemically deposited on CdS was Studied with AES, and the ways to improve quality and yield of the cell were discussed. It was observed that with time increasing, S and Cd enriched at and escaped from the surface of the cell, and Cu contrarily diffused into CdS. A certain functional relation was found between the depth profile of elements analyzed by AES and efficiency of the cell.

A MODIFIED HORIZONTAL GRADIENT-FREEZE APPROACH TO THE GROWTH OF DISLOCATION-FREE Si-DOPED GaAs SINGLE CRYSTALS

MO PEIGEN, YANG JINHUA, LI SHOUCHUN, JIANG DAWEI, ZHAO HUIFANG, ZHANG GUOMIN

1985, 3(4):  355-363. 

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A modified horizontal gradient-freeze approach with quasidouble parabolic temperature profile has been developed for growing GaAs single cryatals. Using this approach, the dislocation-free Si-doped crystals with <111>B and <211> B oriented seeds have been grown successfully. It has been found that the solid-liquid interface is slightly convex and nearly perpendicular to the growth direction during the growth process, indicating good thermal symmetry in the growth region, and so some deficiencies due to the inclined and slightly concave interface in conventional horizontal Bridgman growth could be avoided. Some other features in this approach are also discussed. It is suggested that the effectiveness of dopant Si for reducing the dislocation density of the crystals may be related to the interaction between Si_GaV_Ga complexes and dislocations.

THE SUBSTITUTION OF RARE EARTH IONS IN THE HEXAFERRITES

DU YOUWEI, LU HUAIXIAN, KUI JISHENG, GU BENXI, WANG TINGXIANG

1985, 3(4):  364-368. 

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The hexaferrites were prepared by oxalate coprecipitation method. The barium ions Ba²⁺ in the hexaferrites were substituted by the rare earth ions R (La, Ce, Gd). The maximum substituted quantity of rare earth ions R in the hexaferrites and the effects on the magnetic properties and phase diagram were studied. The main experimental results are as follows.

A STUDY ON TERPENE ANAEROBIC ADHESIVES

GAO NAN, CHEN JEXIANG, XU JINGDE, ZHU YINGYING, QIAN JUNLU

1985, 3(4):  369-372. 

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The syntheses conditions of α-pinene-phenol compound (abbreviated as T-P compound) have been studied. T-P compound was used stoynthesize T-P epoxy dimethacrylate, T-P polyetherdimethacrylate anaerobic monomers. A series of high, middle and low strength torpene anaerobic adhesives were prepared successfully by adjusting the ratio of two anaerobic monomers.

IN-DEPTH DISTRIBUTION OF CARRIER MOBILITY IN SOS FILMS

WANG YING, CHEN QINGGUI, SHI RIHUA, SHI CHANGXIN

1985, 3(4):  373-376. 

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In-depth distribution of carrier mobility can be obtained by measuring the gate capacitance and the transconductance of deep-depletion SOS/MOSFET in linear region as a function of gate bias voltages. The defect scattering mobility can be expressed as μ_EP=μ₀e^-αx₀, where μ₀ and α are two constants characterizing the crystalline quality and the indepth change of defect density with distance x₀ in SOS film respectively. The effect of growth technology and substrate surface quality on μ₀ and α values have been described.