Table of Content

30 September 1985, Volume 3 Issue 3

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Articles

SURFACE EXCITONS IN A POLAR CRYSTAL

GU SHIWEI, ZHANG JIE

1985, 3(3):  189-193. 

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In this paper, the effective Hamiltonian in ground state of surface excitons is obtained by the linear combination operator method and some simple unitary transformations.

INVESTIGATION OF IMPERFECTIONS IN CRYSTALS BY MEANS OF NUCLEAR QUADRUPOLE DOUBLE RESONANCE

CHENG GUANGQIANG

1985, 3(3):  194-200. 

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Field-Cycling-Technique has boon successfully used for nuclear quadrupole double-resonance to investigate imperfections in crystals, to raise the sensitivity of the measurements and to measure the imperfections in Li₃N. Quadrupole splittings of the imperfections and the double-resonance process are analyzed in this paper. At the end of this paper, a brief discussions is given to the measured absorption lines of Li₃N.

POLARITONS (TE MODE) IN A DIELECTRIC PLANAR WAVEGUIDE

ZHOU LICHONG, ZHOU XIAOLING, FANG JUNXIN

1985, 3(3):  201-207. 

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Polaritons (TE Mode) in a dielectric planar waveguide has been studied. Taking ionic crystal of CsCl type as an example and using tight-binding approximation, we consider only the Coulomb interaction between electrons in the conduction band and holes in the valence band for nearest-neighbor sites and prove that when we deal with light-matter interaction, the material system can be regarded as an ensemble of a series of polarization wave oscillators. Furthermore, the intensity of oscillators is calculated and the dispersion relation, of the polaritons in a dielectric planar waveguide is worked out. The result shows significant difference from classical single oscillator model. According to our microtheory, the distances between upper dispersion curves of the guided-wave polaritons are larger than those obtained by using classical single oscillator model for several types of dielectrics which have wider energy bands and weaker interaction between electrons.

NUMERICAL COMPUTATIONS FOR COPLANAR CIRCULAR DISK-SHAPED CRACKS

OUYANG CHANG, XU LINLIN

1985, 3(3):  208-216. 

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In this paper, a computational method for coplanar disk-shaped cracks within an elastic infinite body is presented. The basic idea is to use the single crack solution and the expansions of the local coordinates to reduce the complicated problem into a set of linear algebraic equations. By solving this set of linear algebraic equations, we could obtain the solution of multi-cracks problem finally. Numerical examples for 2, 3, 4 cracks show that the method presented here is quite workable. Results contained in this paper extend the content of "Handbook of Stress-Intensity Factors" by G. C. Sih.

THE RESEARCH OF REGULATIVE METHOD ON ANGLE OF INCLINATION OF STRAIGHTENER

LUO JIASHUN

1985, 3(3):  217-222. 

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In this paper, the anthor investigates computational method on regulation of the angle of inclination by means of geometric characteristics on double envelope of cylindrical surface and the theory of degree of contact between the two curves. Some new results are obtained.

CLOSE-LOOP OPTIMAL SOLUTIONS FOR SOME PARABOLIC SYSTEMS WITH POINT WISE CONTROL (n=2,3)

YAO YUNLONG, YOU YUNCHENG

1985, 3(3):  223-232. 

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Closed-loop syntheses of optimal control is proved for the quadratic optimal problem of some parabolic systems with pointwise control on two and three dimensional domains. Their state feedback operators can be characterized by solutions of linear resolvent equations or Riccati integral equation.

A FUNCTIONAL FAULT MODEL AND A TEST GENERATION PROCEDURE FOR DIGITAL SYSTEMS

MIN YINGHUA, Stephen Y. H. Su

1985, 3(3):  241-248. 

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This paper introduces a functional fault model for digital systems described by Register Transfer Language (RTL). A formal definition of standard statements in RTL is given, the functional faults are thug classified into eight types. A procedure for generating tests for any given functional fault is presented by using the inverse operation of the ETL description of the system under test. It is interesting to know that once the behavior of a digital system is described by RTL, similar ideas used in test generation for stuck-at faults can be pushed up to RTL level with each RTL statement as a "Component" of the system.

RADIOASTRONOMICAL MEASUREMENTS OF THE ATMOSPHERIC ABSORPTION AT THE CENTIMETER WAVELENGTH

YUAN HUIREN, PEN YUNLOU, XUE YINZHANG, WEI SHUANGLIN, ZHOU FENGAN

1985, 3(3):  249-254. 

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In this paper, we discussed the basic principles and methods for measuring atomspheric absorption at λ=2.5cm, 3.2 cm and 7.5 em by observing electromagnetic radiation of the moon and listed the results of measurements. We found that the results of measurements coincide with the theoretical value at λ=3.2cm.

STUDIES IN OPTICAL DEVELOPMENT OF FREE RADICAL PHOTOGRAPHY

ZHENG GUANGLIN, SHI DAOJUN, HUANG XIAOLAN

1985, 3(3):  255-261. 

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A quantitative characterization parameter in. optical development of free radical photography K_max is proposed and its significance and method of measurement are elucidated. Effects of the wavelength (used) on the optical development of Leuco crystal violet/CBr₄ film and the effects of the adhesive medium and temperature on the rate of optical development have been studied. The activation energy is estimated at about 10kcal/mole.
The induction period of optical development has also been interpreted. There are two different processes in optical development. In the induction period oxygen quenching of the excited dye molecules by the diffusion-control predominates while in the main period of the reaction energy transfer-control photochemical reaction predominates.

A NEW WAY FOR IMPROVING THE CRYSTALLINE QUALITY OF SOS FILMS

CHEN QINGGUI, SHI RIHUA, CAI XIJIE, WU YUNGZHONG, SUN OHENGLONG, PAN YAOLING

1985, 3(3):  262-266. 

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In this paper, a new method for improving the crystalline quality of SOS films is developed.lt consists of three steps:(1) A thin amorphous silicon layer is prepared by electron beam evaporation. (2) The wafer is annealed in a hydrogen atmosphere. (3) The required thickness (0.6-0.8μm) of SOS film is deposited by the standard OVD method on the thin silicon layer. The resulting SOS films are examined by reflection electron diffraction, Nomarski phase interference microscopy, carrier concentration measurement and optical absorption measurement. The results show that the crystalline perfection of the film is good,the optical absorption factor F_A ≤ 140×10⁶cm^-2. The autodoping is expressed and the carrier concentration is lower than 1×10¹³cm^-3.

A STUDY ON FORMATION PROCESS OF Fe₃O₄

DU YOUWEI, LU HUAIXIAN, GU XINGYUN

1985, 3(3):  267-273. 

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The magnetic properties of magnetite prepared by chemical coprecipitation are closely related to the precipitator mixing method, concentration of solution and molar ratio of Fe²⁺/Fe³⁺ and Fe²⁺/OH^- ions etc. When the alkaline solution is slowly added to the mixed aqueous solution containing ferric and ferrous ions, the process of formation of Fe₃O₄ consists of two steps.

LASER-INDUCED VAPOR DEPOSITION OF SILICON USING A PULSED Nd:YAP LASER

YANG JINGRAN, WANG LIANJIE

1985, 3(3):  274-276. 

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Atomic vapor produced by pulsed Nd:YAP laser with, its beam focused on a silicon wafer has been used to deposit silicon film on substrate at room temperature.
A 300~400 us pulsed Nd:YAP laser was used to vaporize a high-purity silicon wafer contained in an evacuated cell. The laser energy at 1.075μm was 8J per pulse.

EXISTENCE OF GLOBAL SOLUTION OF A CLASS OF NONLINEAR HYPERBOLIC CONSERVATION SYSTEMS

ZHENG XUEHENG

1985, 3(3):  277-282. 

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In this article, two conditions are given to define a class of non-linear hyperbolic conservation systems, for which the reference solution on whole of the x, t-plane can be defined -to demonstrate the existence of the global (weak) solution. The equation system which describes the one dimensional flow of isentropic ideal fluid is included in this class.