Table of Content

31 March 1992, Volume 10 Issue 1

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Articles

ITERATIVE AND FINITE DIFFERENCE METHODS FOR SOLVING A SYSTEM OF NONLINEAR ELLIPTIC EQUATIONS

GUO BENYTT, JOHN J. H. MILLER

1992, 10(1):  1-24. 

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Iterative and finite difference methods are proposed for a system of nonliear elliptic equations. The existence of solutions and error estimations of approximate solutions are proved. The numerical results support the.analysis.

THE TEMPERATURE DEPENDENCE OF THE TWO-DIMENSIONAL POLARON EFFECTIVE MASS

WANG ZONGGANG, GU SHIWEI

1992, 10(1):  25-30. 

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

THE SAMPLING RULE FOR CALCULATING THE LEAST SQUARE REFERENCE CENTER AND ROUNDNESS ERROR

ZHU XUNSHBNG, XUE BINYUAN, BEI JIYAO

1992, 10(1):  31-37. 

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This paper discusses the number of sampling points necessary for representing the roundness error of a closed curve without distortion. Through mathematical deduction by the authors, the relationship between the center coordinates of a least square circle of a curve with statistical roundness error and its Fourier coefficients is obtained. Then the sampling rule which must be obeyed is acquired, and the verification results of the test problem and practical periphery are given.

UNIQUENESS AND ACCURATE SOLUTION OF ROUNDNESS ERROR ACCORDING TO THE MINIMUM CONDITION

MAO YOUGEN

1992, 10(1):  38-42. 

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This paper makes an inquiry into the characteristics of the mathematical model for solving the roundness error according to the Minimum Condition. It is shown that the solution of the mathematical model is unique. And this paper also shows some different kinds of thinking and methods for solving the accurate solution.

A NUMERICAL INVERSE METHOD FOR DETERMINING FILM PARAMETERS OF UNIAXIAL ANISOTROPIC FILM WITH ELLIPSOMETER

ZHU KONG, WEI YU

1992, 10(1):  43-48. 

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A numerical Inversion method of ellipsometry has been developed for determining optical constants and thickness of the uniaxial anisotropio film, the optical axis of which is perpendicular to the film surface. The method of changing film thickness has been proposed to obtain multiple independent ellipsometrio equations for the separate calculation of optical constants and thickness of the film, and reduce the three-parameter problem to a two-parameter one. A flow chart of the numerical inverse program is given and an example applied to L-B films is illustrated.

THE SYSTEM OF SOLID SPECIFIC HEAT MEASUREMENT WITH SCANNING METHOD AND ITS ANALYSIS

ZHOU CHENGHAO, ZHANG YIBING, CH. SAJJAD AHMAD, EUAN MEIPING, JIN BIANJUN

1992, 10(1):  49-52. 

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This paper introduced and analysed the experiment system for measuring solid specific heat with the scanning method. Using the experiment system, we measured the specific heat of the copper of 99.7% purity. Its data showed its deviation between 80K and 260K is less than,l% from the National Standard Reference Data System.

THE THEORY OF SEPARATION EFFECT OF PLATE ELECTRODE GRADIENT FIELD

YANG TIQIANG, LIANG DAOMING, LIANG YUNZHANG

1992, 10(1):  53-56. 

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The article expounds in theory that the plate electrode gradient field has a remarkable separation effect on the mixtures of different electric oharaoters.lt is found that to use the plate electrode gradient field is an ideal and feasible eleotrio separation technique.

THE COLOR FOR TV AND THE COLOR VISION IN LOW BRIGHTNESS

OUYANG XITONG, GAO SHUXIANG

1992, 10(1):  57-62. 

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In this paper the approximate and brief spectral luminous efficiency curves and ohromaticity diagrams for mesopio vision are given. With these, it is easy and convenient to explain the main reasons for the color change of bodies and for the color distortion of TV in. low illuminance or low brightness.

THE SECOND ORDER BEAM OPTICS OF A DIPOLE MAGNET WITH A SYMMETRY PLANE

HU NAIXIONG, XIMEN JIYB

1992, 10(1):  63-70. 

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This paper gives the expression of the vector potential produced by a dipole magnet with a symmetry plane. The second order trajectory and second order aberration are obtained by using the variation theorem. It is verified that Liouville's theorem still holds under such circumstances. The beam ellipsoid deformed by second order aberration becomes a new ellipsoid after appropriate modifications, and still works according to first order transport theory. The seuond order beam optics is therefore established.

TWO-DIMENSIONAL NUMERICAL ANALYSIS OF THE NARROW-GATE EFFECT

YANG BIAO, JI CHJAOREN

1992, 10(1):  71-77. 

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The two-dimensional numerical analysis using constant approximation, obtained by Chung and Sah, has been improved by adopting the mobility model. It is found that the slope of the oonduotanoe-gate voltage curve changes from increase to decrease with increasing gate voltage, and the narrow-gate shift of the threshold voltage is larger than that obtained from constant mobility approximation. A new model is proposed here to predict the narrow-gate shift of the threshold voltage. When the conduotanoe-gate voltage characteristics of one narrow-gate MOSPET and one wide-gate MOSFET are got from 2-D numerical analysis or experimental measurement, the threshold voltage shift of any other.narrow-gate MOSFET can then be determined subsequently. This model is checked -and agrees well with the 2-D numerical and experimental results.

A SYSTEM FOR CHARACTERIZATION OF SEMICONDUCTOR MATERIALS USING SCANNING PHOTOLUMINESCENCE

ZONG XIANGFU, WENG YUMIN, LIU SONG, QIN XI

1992, 10(1):  78-84. 

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In this study, the authors describe a computer-controlled scanning photoluminesoenoe (PL) system which has been designed for mapping PL intensities of semiconductor wafers or epitaxial layers up to 3 inches in diameter. Sample materials included Si, GaAs and so on. It can be used for investigation to detect defects and shallow impurities, and to show their distributions in semiconductor materials. PL is paiticularly sensitive for identifying impurities and mapping wafers to determine the distribution of defect densities over the surface of a wafer. Information from spectra and wafer maps is presented and discussed. The present scanning PL technique can be used as a simple, nondestructive, but sensitive tool in evaluating the uniformity of the near-surface layer of semioonduotor substrates and, therefore, is ideally suited for device characterization.

CATALYST PRERATION OF POLYMER BOUND RUTHENIUM (Ⅲ) COMPLEXES CONTAINING BINUCLEAR LIGANDS AND ACTIVITY OF CATALYTIC HYDROGENATION

ZHAO WEIJUN, WANG LING, ZHANG SHUJI, FANG YANQUAN

1992, 10(1):  85-94. 

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With Chloromethylated polystyrene divinylbenzene as a support, the funotionalizened polymers containing N-P, N-0, or N-N binuelear ligand were pi-epared. These functionalized polymers were chemically bound with RuCl₃ forming supported catalysts. Used in the hydrogenation of Diketo-alcohol the catalysts displayed high activity and selectivity.