Table of Content

30 September 1987, Volume 5 Issue 3

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Articles

TRANSIENT EM FIELD

SHEN HAOMING

1987, 5(3):  189-196. 

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An introduction on transient EM field and EM pulse is presented. The application, properties, contents and methods of transient field are summed briefly.

SOME NEW APPROACHES TO DETERMINING MATERIAL FRINGE VALUE

OUYANG CHANG, YE NING

1987, 5(3):  197-202. 

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In this paper, after a research for Photometric Compensation Methods on the-determination of non-integer isoohoromatio fringe order, two methods:Darkest Method and Intensity Method, to determine material fringe value are developed with a Digital Picture Computer. Here, authors deduced the fringe order formulas in Intensity Method, and established a Material Fringe Value Fast Determination System (YES system). Besides, another method, Gray Method, was also presented. With an axial tension plate, a pure bending beam and a diametral loaded disk as models, the determination of each material fringe method was performed. It takes only 3 to 4 minutes to make one determination with this system and the precision is high. This lays a foundation for Eeal Time Photoelasticity.

RESOLVING POWER OF DIFFRACTION LINES ON THE EQUATOR OF MONOCHROMATIC X-RAY FOCUSSING PHOTOGRAPH

GUO CHANGLIN

1987, 5(3):  203-211. 

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In this paper, the various factors affecting the reselving power of diffraction lines on the equator of monochromatic X-ray focussing photograph are analyzed in detail. The relationship equations and calculated results of the broadening of diffraction lines caused by wavelength dispersion of X-ray characteristic spectra, wavelength difference of Kα-doublet, quality and inexact focussing of monoohro-mator, specimen thickness and grain size are given. According to the calculated and experiment results, the synthetic factor affecting the resolving power of diffraction line is discussed.

BRILLOUIN SCATTERING IN PIEZOELECTRIC SEMICONDUCTOR CRYSTAL ZnO

ZHENG HAOPING, ZHAO MINGZHOU

1987, 5(3):  212-219. 

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The derivation of the acoustic wave equation which is valid for piezoelectric semiconductor crystals of any symmetry and for any acoustic propagating direction is presented. Three mechanisms contributing to Brillouin scattering in high resistivity ZnO crystal are analysed. They are the elasto-optic effect, rotational contribution of shear wave and the electro-optic effect induced by the aocompaning potential. Thermal Brillouin scattering in ZnO crystal is performed. All of five independent elastic constants of ZnO crystal in high frequency range at room temperature are measured and the values are smaller than those reported in lower frequency by about 4.5%. Four photoelastio coefficient relations are given and the curve of the reciprocal velocity of quasi-longitudinal acoustic wave in x-z plane 10 depicted.

INVESTIGATIONS OF ELECTRICAL PROPERTIES OF m-NITROANILINE (m-NA) CRYSTAL

SHI ZIKANG, HUANG GONGPAN, SU GENBO

1987, 5(3):  220-224. 

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The m-nitroaniline crystal is a new polar crystal material. Single crystal samples with dimentions of 50×40×30mm³ have been grown in our laboratory. Its electrical properties such as the dielectric constant, dc-, ac-resistivity, loss angle in the orientation of no-polar axes, and pyroelectric character near melting point are investigated and cited for the first time.

A STUDY OF MAGNETIC PROPERTIES AND FERROMAGNETIC RESONANCE OF (Co_0.95-xFe_0.05Nb_x)₇₄B₁₈Si₈ AMORPHOUS ALLOYS

LI DEXIN, LI GUODONG, ZHANG WUXIN, TANG WEIZHONG

1987, 5(3):  225-230. 

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The paper investigates the effect of a small quantity of Nb on amorphous alloys CoFeBSi using magnetic measurement and differential thermal analysis. Using a ferromagnetic resonance method, magnetic properties of anisotropies are studied and so is the effectss of heat treatment on the anisotropies.

DESIGN AND MANUFACTURE OF WAVEGUIDE ELECTROOPTIC BRAGG GRATING LENSES

XU ZHENGQUAN, LIU ZITING

1987, 5(3):  231-237. 

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This paper hag probed into a new type of waveguide lenses which may be called the waveguide eleotrooptio Bragg grating lens. According to the eleotrooptio effect of eleotrooptio-crystal and the principle of diffraction of Bragg grating, the refractive index change can be induced in the waveguide under an aluminum electric pole when a suitable do voltage is applied to it and the chirped grating with inclined stripes is formed. The pole is a chirped interdigital one with inclined stripes made with conventional lithographical technique. The grating diffracts and focuses the incident light beam and acts as a lens. This type of lenses has the advantages of being simple in manufacturing and easy in integrating with other components of integrated optics. Our grating has a 40mm focal length and 14μm diameter focal spot.

MODULATION TRANSFER FUNCTION MEASUREMENT OF TV PICTURE TUBE

SHEN GUOHUA, PAN YULIAN, WANG MINGLUE, FAN CHENGSHAN

1987, 5(3):  238-243. 

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A new instrument for modulation transfer function (MTF) measurement of TV picture tube has been designed. It can measure MTF of different areas on screens under different conditions with precision up to +3%, and the resolution is measured in accordance with the standards issued by the National Bureau of Standards, the People's Republio of China. A way to avoid false resolution phenomenon when using a compression method is given in the paper.

NUMERICAL MODELING OF SUPERSONIC FLUORINE/HYDROGEN COLD FLAME IN LAMINAR MIXING REGIME

ZHUANG QI, FENG HAO, LI MU, LI ZHONGYUAN

1987, 5(3):  244-248. 

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By using a two-dimensional boundary layer model, the temperature, HF(v) concentrations and Mach number profiles of the cold flame, as well as the relation of flame length to the lateral diffusion distance are obtained. The calculations were performed on a Nord 500 digital computer. The Fortran code is programmed by using Gear's automatic numerical integration method.

COLD EMISSION FROM TIN OXIDE FILMS

ZHANG ZHUANGJIAN, YANG XILIANG, SUN YUNLONG, GAO LONGGTTAN

1987, 5(3):  249-253. 

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The high-resistance region in Tin Oxide film acts as a cold electron source with noncollimated electron output current of the order of 100-200 μA. The primary experimental results show that the high-resistance region with the capability of electron emission has a change in composition, and the energy distribution of the emitted electrons is different from that of the field emission. The magnitude of the electron current is influenced by both the gaseous component and the pressure in the test chamber.

A SIMPLE THEORY OF FRICTION-FREE HILL IN CROSS SHEAR ROLLING

ZHAO ZHENGCHAI, TAN XINGHAI

1987, 5(3):  254-259. 

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In this paper, a simple theory of frintion-free hill in cross shear rolling is presented. Formulas for calculating pressure per unit surface, mean pressure per unit surface and total pressure are proposed.

P-VALUED LOGIC AND ERROR-CORRECTING CODES

XIAO GUOZHEN

1987, 5(3):  260-264. 

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This paper treats the error-correcting codes over GF(p) as a digital network problem, and presents a new mathematical model of errorcorrecting. The traditional coding method is simplified. The linear block code is transformed into a system of p-valued logical function, and the system is expanded in a finite Oherestenson series.

APPLYING RES IN TO HYDROLYSIS AND SEPARATION OF DIMETHYL SEBACATE

GUI WEIZHI

1987, 5(3):  265-268. 

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Using strong acid or strong base as a hydrolyst is liable to corrode equipments:There is hardly any difference between sebacic acid and dimethyl sebaoate, each of them being dissolvable in ethanol, ether and ketone. To keep sebaoio aoid separate from dimethyl sebacate by ordinary filtration or recrystallization method is too difficult for one to hope to succeed.
Making full use of acidic, basic catalysis and selected adsorption of resin, a new process of applying resin to hydrolysis and separation of dimethyl sebacate is introduced. This new process is economically suitable for industrial production.

ELASTIC PARAMETER MEASUREMENTS OF NEW CRYSTALS BY BRILLOUIN SCATTERING AND COMPUTER FITTING PROGRAM

ZHANG PENGXIANG, JIANG ZUIMIN, LIU YULONG, PANG YUZHANG

1987, 5(3):  269-274. 

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To make total elastic parameter measurements of crystals is very difficult due to the fact that the size of crystals is small, especially for new materials. We improved the Brillouin scattering technique, and using a small crystal as a spherical sample, measured the sound velocity and anistropy. The fitting programs are made to deduce the total elastic parameters from Brillouin measurements. The possible problems in fitting and ways of solving the problems are discussed.

INFRARED ABSORPTION SPECTRA OF PLASMA ANODIZED FILM ON THE GaAsWAFER

LIU LING, YU JUHUA, LIU CHUNRONG

1987, 5(3):  275-278. 

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The infrared transmittanoe of high resistivity GaAs monoorystal and the plasma anodized film on GaAs substrate are measured by using an IR-450 S type infrared spectrophotometer. The experiments show that, in the range of 2.5-13.6 μm wavelength, the transmittance of GaAs monocrystal with thiohness of 0.70 mm is greater than 50%. In the range of 2.5-10 μm wavelength, the anodized film with thickness of 0.590 un has some anti-reflection effect on GaAs. In 10-26 μm wavelength, a strong and wide infrared absorption band is observed. This absorption band can be utilized to examine plasma anodized film on the GaAs wafer.

MICROWAVE TECHNIQUE FOR EXAMINING CORONARY ARTERIOSCLEROSIS

WANG BAOYI, PENG BINGZHONG, TANG JINGXIAN, XU LAN, LIU YONGQING

1987, 5(3):  279-282. 

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A new technique for examining coronary arteriosclerosis of body is presented in this paper. Precordial region of body was irradiated by low power microwave beam, which was modulated by the movement of heart. Relative information of reflected modulation wave from chest was extracted and analysed by a microcomputer in frequency domain. Experiments have shown that spectrum components from healthy body mainly locate in low frequency and the magnitude of higher frequency line is small. On the contrary, the magnitude of spectrum line in higher frequency region from coronary arteriosolerosists is stronger than that from a healthy body.