Table of Content

30 June 1985, Volume 3 Issue 2

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Articles

SUPER MODE CONCEPT AND APPLICATION

HUANG HUNG-CHIA

1985, 3(2):  95-99. 

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Analytic study of optical waveguide characteristics may be much facilitated by a judicious choice of the types of modes (ideal modes, local modes, super modes) for field expansion. The present note will provide examples to illustrate this viewpoint, which seems not to have received sufficient attention.

QUANTUM ELECTRODYNAMICAL MODEL THEORY OF PLANAR WAVEGUIDE SYSTEM——NON-SPATIAL DISPERSION CASE

ZHENG HANG, FANG JUNXIN

1985, 3(2):  100-107. 

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A reasonable quantum electrodynamical model is introduced in the present article for the interacting system of a planar waveguide and the electromagnetic field. The response to external electromagnetic perturbations of this interacting system is discussed using the linear response theory, and is proved to be fully determined by the physical properties of the intrinsic elementary excitations guided-wave polaritons of the system. The theory is useful for discussions of propagation, transmission, reflection, scattering and absorption of electromagnetic waves as well as the propagation of external electric-, magnetic-or acoustic-perturbations in the planar waveguide.

CLOSED-LOOP OPTIMAL SOLUTION TO QUADRATIC BOUNDARY CONTROL OF HYPERBOLIC SYSTEMS

YOU YUNCHENG

1985, 3(2):  108-113. 

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In this paper, closed-loop synthesis to an optimal problem with respect to quadratic criterion is proved for mild solution of hyperbolic boundary control systems of Dirichlet, Neumann or mixed type. Feedback operators are characterized by solution of linear Fredholm operator integral equations.

ON AUTOMATIC DIVIDING OF CHINESE WORDS

WANG YUNGCHENG

1985, 3(2):  114-119. 

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The present paper summarizes several well-known methods for autodividing Chinese words, and at the same time proposes a new method, which has been proved in practice to be both feasible and simple.

SOLVING THREE CLASSES OF RECURRENCE EQUATIONS

ZHU HONG, DUAN ZHENHUA, AN JIAPENG

1985, 3(2):  120-127. 

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In this paper, we analyse three classes of recurrence equations by, means of harmonic series, binary trees and Pascal configuration. We get general expressions of their solutions. These recurrence equations and their solutions are useful for us to research in computer science.

THE MODIFICATION OF BEAM DEFLECTIVE METHOD FOR MEASURING REFRACTIVE INDEX PROFILE OF A FIBER PREFORM

LIAO YKNBIAO, TIAN QIAN, WU GENGSHENG

1985, 3(2):  128-132. 

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In this paper, a modificatory beam deflective method, a method for nondestructive measurement of refractive index profile of a fiber preform, is described. Near matching fluid instead of accurate matching fluid is used in this method, the diameter of incident beam used being reduced at the same time. The experiments show that the measurement results are reliable. The measuring time can be saved and the accuracy promoted.

THE REVISION ABOUT THE LINEWIDTH FORMULA OF LASER

YAN ZUQI

1985, 3(2):  133-136. 

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In the literature[1], the calculating methods about the storage energy, the net power loss of coherent light in the cavity and the linewidth of laser light in accordance with such laser in which the distribution of light intensity was transverse nonuniform had been discussed. In this paper, the discussion is extended to the general laser in which the transverse and the longitudinal distribution of light intensity are all nonuniform, and the linewidth formula of laser light, which has been shown by Townes, Maitland, is revised. And the relative revised value resulted from the nonuniform distribution of light intensity is estimated with a cylindric laser of single mode.

FERROMAGNETIC RESONANCE IN ARBITRARY ORIENTED PLANE OF CUBIC CRYSTAL

HE YUQUAN

1985, 3(2):  137-142. 

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The ferromagnetic resonance (FMR) relations in magnetically anisotropic single-crystal ferrites with cubic symmetry have been reexamined. Detailed analyses are presented for idealized single-domain spherical specimens. The total free energy expression which includes the contribution of the first-and second-order cubic anisotropy was employed to derive general FMR formulas. The deviation between magnetization equilibrium direction and applied field direction is strictly taken into consideration. The theory of ferromagnetic resonance previously developed is extended to handle the case for the static magnetic field with an arbitrary orientation with respect to the orystallographic axes. The theory is applied to several practical examples and is found to yield results which are in good agreement with experimental data. On the basis of these methods, the cubic anisotropy constants and the effective gyromagnetic ratio for a material can be calculated from measurments in any crystal planes.

A THREE-DIMENTIONAL FIELD THEORY FOR A FERRITE LOADED CYCLIC H-PLANE WAVEGUIDE JUNCTION

SONG YINSUO

1985, 3(2):  143-154. 

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In this paper, Copplestone's method is extended to analyse a ferrite loaded cyclic H-plane waveguide junction. Solving and matching in the electromagnetic fields in each region and simplifying the field equation are developed. The internal problem (solving and matching in the e. m. field) of the junction is transformed into a scattering matrix by menas of the eigenvalues of junction. A three-dimentional field theory for the ferrite-loaded cyclic H-plane waveguide junction is thus established. For g=3, the computed values agree well with experimental results.

A MEASUREMENT METHOD OF METAL-SEMICONDUCTOR CONTACT RESISTANCE

WU YUNZHONG, SUN CHENGLONG

1985, 3(2):  155-160. 

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The influence of spreading resistance and probe-metal film contact resistance on the contact resistance of metal-semiconductor is generally neglected in the conventional methods used for measuring metal-semiconductor contact risistance. Thus errors would be caused when one uses these methods to measure the metal-semi conductor contact resistance.
In this paper, according to the radial transmission line mode of circular ring electrode, an equation bearing the quantitative relationship between metal-semiconductor contact resistance and spreading resistance of thin film, probe-thin metal film contact resistance, current and voltage is derived. Based upon the equation, a new mode for measurement of metal-semiconductor contact resistance using four-point probe method is proposed. The metal-semiconductor contact resistance is accurately measured and the error sources from this measurement are discussed.

MICROWAVE PARAMETER MEASUREMENTS FOR GaAs DUAL-GATE MESFET

YANG XINMIN, WANG WEIYUAN, WANG WENQI

1985, 3(2):  161-168. 

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The microwave parameters minimum noise figure NF_min associated gain G_a and gain reduction G_R of a low noise GaAs dual-gate MESFET for UHF applications were measured by means of the mid-frequency attenuation method in microstrip test circuits. The S parameters were measured by means of network analyser. From the experimental data, the best noise figure NF₀ of 0.8dB was obtained. The G_a and G_R amounted to 11.5dB and 48dB, respectively. It was shown by S parameters that the dual-gate MESFET was stable over 0.5-2GHz.

THE MAGNETIC AND MOSSBAUER STUDY OF Y-Gd-Ca-V-In IRON GARNETS

ZHANG PANLIN, LING QIFEN, GUO SHUJIAO, LI GUODONG, ZHANG YIAOXI, ZHANG LI

1985, 3(2):  169-175. 

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The magnetic properties, ferromagnetic resonance (FMR) and Mossbauer effect of Y_1.2Gd_1.2Ca_0.6V_0.3In_xPe_4.7-xO₁₂ with x=0, 0.2, 0.4, 0.6 and 0.8 were studied experimentally. Using Neel, Gilleo and Dionne theories, the magnetic moments and Curie points were calculated respectively. It is shown that the experimental results were well in agreement with the Gilleo (Curie points) and Dionne (saturation moments) theories. The linearly incresing dependence of FMR line width with frequency (3.6-17 GHz) were discussed in terms of phenomenal theory. The occupancy of V⁵⁺ and In³⁺ ions in tetrahedral (d) and octahedral (a) sites were determined indirectly from the paramagnetic Mossbiuer spectroscopy.

PROPERTY OF SOLITARY WAVE SOLUTIONS OF SOME NONLINEAR DISPERSION EQUATION

XU BAOZHI

1985, 3(2):  176-180. 

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This paper discusses the solitary wave solutions of nonlinear dispersion Equation:
u_t+(au+βu₂)_x+γu_xxx=0 (1)

THE RELATION OF INPUT-COUPLING EFFICIENCIES TO INCIDENT WAVE PROPAGATION CONSTANTS FOR PRISM COUPLERS

LI YUSHAN, JIN FENG, LIN SHENGQIANG

1985, 3(2):  181-183. 

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For the coupled system of the glass prism and the glass waveguide formed by ion exchange, changes of the input-coupling efficiency η as the incident wave propagation constant β_i have been measured by detecting reflective light intensity of the prism base at different coupling gaps. There by, physics paramete rsrelated to input-coupling have been determined.

78 K INFRARED ABSORPTION METHOD FOR MEASURING THE OXYGEN CONTENT IN SILICON

LI YUEZHEN, SHEN JINYUAN, REN NING, WANG QIMIN

1985, 3(2):  184-185. 

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A more accurate calibration curve at 78K for measuring the oxygen content in silicon single crystals has been established by the infrared absorption difference method. The resulting formula is N₀=2.6α ppmA, or N₀=1.3×10¹⁷α atoms/cm³ where α represents the IR absorption coefficient.

IN SITU THE MEASUREMENT METHOD OF EMISSIVITY FOR 8-14μm

LU SIHUA

1985, 3(2):  186-188. 

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The method described in this paper provides an improvement on,T. K. Buettner's method. It is simpler and more rigorous than that of Buettners. The instrumental error and personal error are discussed in detail. No significant differences have been found between our results and the generally accepted data.