Table of Content

31 December 1986, Volume 4 Issue 4

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Articles

POLARITONS IN A DISORDERED MATERIAL An Application to the Theory of Optical Waveguides

CHEN HONG, WU XIANG, FANG JUNXIN

1986, 4(4):  283-288. 

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In the present article, the properties of polaritons in a disordered material are studied under the Coherent Potential Approximation. Our main results are ag follows:(1) The concept of an effective wave vector can be used to describe the polariton of a dielectric glass, and the criterion for the existence of effective wave vector is also given. (2) The polariton dispersion of a disordered material is similar to its crystalline counterpart, which is consistent with recent experiments. (3) In the sense of the attenuation due to the disorder of the structure, the phonon-polariton is bettor than the exoiton-polariton in long-distance optical fibre communications. As an application of the present theory, we have derived the dispersion of guided-wave polaritons in a planar disordered waveguide.

STUDY ON APPLICATION OF OPTICAL FIBER IN ELECTRON AND GAMMA RADIATION DIAGNOSTICS

WANG YAOCAL

1986, 4(4):  289-297. 

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Optical fiber used as a sensor converting radiation energy into Oerenkov light energy and a transmission line can form wide band electron and gamma radiation diagnostics system. Application of optical fiber will considerably improve frequency response characteristics of measurement system. Present system is able to break the record of bandwidth limit of routine systems. In this paper,the sensitivity of optical fiber to Oerenkov light emitted in itself by incident relativistic electron beam and the sensitivity of the optical fiber to Oerenkov light emitted by Compton electrons created by incident gamma ray are theoretically calculated. The mathematical expressions for sensitivity, dynamic range and bandwidth of the system are given. These forulas are of great importance in estimating system performances and demonstrating its applicability. The system has maximum sensitivity at the wavelength of 800nm. We have also performed an experimental calibration for sensitivity of the sensor to γ-ray, and a recommendation value for the sensitivity is given. Its bandwidth is expected to be more than 500 MHz. When the system is used to measure very fast pulsed radiation, it shows its distinctive advantage.

LASER VELOCIMETER IN MEASURING BOILER WATER-MODELS IN POWER STATION

TANG KAIYUAN, SUN YUSHENG, ZHANG ZINONG, LI MENGSHI, ZHANG GAIGEN, XUE LINDE, SHEN XINGEN

1986, 4(4):  298-305. 

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A directional two-dimensional laser doppler velooimeter is used to develop an accurate quantitative method for the measurement in the velocity field of UP once-through boiler's water-model. The paper introduces the measurement of tha same cross section before and after changing the nose. The result provides soientino basis for designer.
The water-model in association with the laser velooimeter enables the measurement of water-model to go forward from the stage of a qualitative observation to that of a qualitative and quantitative analysis. Thus a new way in boiler investigation and boiler design is provided.

THERMOLUMINESCENCE DATING USING ALPHA DOSE:A METHOD OF IMITATION DISCRETION

WANG WEIDA, ZHOU ZHIXIN

1986, 4(4):  306-313. 

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The thermolnminescence (TL) authenticity measurement is an important technique in archaeology. However, some modern fake reproductions have given a challenge to routine TL dating.
In this paper, a TL dating method using alpha dose is described. This method is reliable because alpha dose cannot be faked. The method is experimented on the imitated sherds of pottery and on the ancient bricks. It is found that the dates gained by these measurements agree very well with the dates of themselves.

THE TEMPERATURE CHARACTERISTICS ANALYSIS OF THE INTEGRATED TEMPERATURE SENSOR

YAN ZHIXIN, CHEN JIAJUN

1986, 4(4):  314-321. 

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In this paper, the basic principle of the integrated temperature sensor is described and the analytic formula of circuit temperature coefficient is derived. The relationship of temperature measurement accuracy with process tolerance is simulated quantitatively by SPICE, and the optimal design for this circuit is given.
The measurement results for the temperature characteristics of SL 616 Integrated Temperature Sensor, which was developed for the first time in China, show that the. accuracy of temperature measurement is about 1℃ in the range -40℃ to 120℃.

ON THE LOWER BOUND OF CHARTRAND S PROBLEMS IN SIMPLE GRAPHS

LIU GUIZHEN

1986, 4(4):  322-325. 

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In this paper, it is shown that if a simple connected graph G contains spanning trees having m and n end-vertices respectively and m<n, then for any integer k, m<k<n, G contains, at least, ρ+ spanning trees having k end-vertices where ρ is the circuit rank of G.

ANALYSIS OF PARTIALLY FILLED WAVEGUIDES BY HIGH-ORDER FINITE-ELEMENT METHOD

XU SHANJIA., S. T. PENG

1986, 4(4):  326-332. 

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We apply here the second-order finite element method to the boundary-value problem of waveguides filled with inhomogeneous dielectrics. The coupling matrix of high-order element and other related formulas are developed and cast in a form that is convenient for computer programming. To determine the accuracy obtainable from the finite-element method of various order, the eigenvalues of a slab-loaded rectangular waveguide, which is amendable to an exact analysis, are computed by the first-and second-order method. It is shown that the accuracy of the second-order method is 10-10³ higher than that of the first-order method. The relative efficiency of the first-and second-order method is also discussed on the basis of numerical analysis by a computer.

THE DETERMINATION OF SURFACE BAND BENDING AND ELECTRON AFFINITY OF GaAs BY MEANS OF ULTRA-VIOLET PHOTOELECTRON SPECTROSCOPY

DONG GUOSHENG, DING XUNMIN, YANG SHU, WANG XUN

1986, 4(4):  333-337. 

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According to the value of energy difference between Ga3d core level and the valence band maximum of GaAs precisely determined by Kraut et al., the position of Fermi level with respect to the valence band maximum at the surface and the surface band bending of clean GaAs (111) can be determined by measuring the exact binding energy of Ga3d level in the UPS experiment. The electron affinity of GaAs can also be obtained by measuring the work function from the threshold of secondary electron energy distribution in. the UPS spectrum. For the clean GaAs (111) (2×2) Ga-riohed surfaces prepared by Ar ion sputtering followed by heat annealing, the Fermi level pinning at the surface can be found with a pinning level sited about 0.75 eV above the valence band maximum, which coincides with the acceptor level observed by Spicer's group on. GaAs (110) surface.

POLARONS IN A SEMI-INFINITE POLAR CRYSTAL

GU SHIWEI, ZHANG JIE

1986, 4(4):  338-342. 

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In this paper, the effective Hamiltonian of a strong coupled surface polarons in a polar crystals is obtained by means of a linear combination operator method and a simple unitary transformation. For the two limit cases of electrons near to and far from the crystal surface, analytical formulas of image potential and self-trapped energy are obtained.

A POLYCRYSTALLINE MODEL OF THE SAW PROPERTIES OF ZnO PIEZOELECTRIC THIN FILM

ZHANG XIAOZHONG, ZHAO MINGZHOU

1986, 4(4):  343-350. 

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The effects of lattice distortion and structural defects of the polycrystalline film have been taken into consideration. A polycrystalline model of ZnO piezoelectric thin film has been established to calculate the SAW velocities and effective electromechanical coupling factors of ZnO-glass and ZnO-fused quartz structure. The calculated values of the polycrystalline model fit the experimental values better than that of simple crystal model. The analysis based on the polycrystalline model also show that the standard deviation of C-axis orientation has only minor influence on the SAW properties of ZnO piezoelectric film and the lattice distortion is the prime detrimental factor.

DETERMINATION OF ANODIC POLARIZATION CURVES AND ELECTROCHEMICAL SYNTHESIS OF DECANEDIOIC ACID

KUEI WEITZE

1986, 4(4):  351-355. 

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A new method of electrochemical synthesis of decanedioic acid is introduced and a diaphragm cell that can be used economically in industry has been designed. Through appraisement of the product, it is proved that the electrolytic method has such features as separating products easily, as possessing higher purity and higher productivity.

PREPARATION AND ELECTRIC CONDUCTIVITY OF MODIFIED SrZrO₃ CERAMICS

WANG PINGCHU, ZENG SHAOXIAN

1986, 4(4):  356-360. 

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The preparation method of SrZrO₃ ceramics doped with Al₂O₃, CaO, Cr₂O₃ and Fe₂O₃, and the influence of the dopants on the conductivity of the samples were studied. The samples were sintered with conventional oeramic technique at 1750-1800℃. For 90% SrZrO₃+5% Cr₂O₃+4% CaO+1% Al₂O₃ (wt) composition, the activation energy of conduction is about 17.6 kcal/mol, and for SrO+ (ZrO₂) _0.9+ (Fe₂O₃) _0.05 composition, about 4.53kcal/mol. They have higher conductivity and can be easily sintered. They are promising for high temperature applications.

THE IMPACTS OF TWO MODE COUPLING ON THE LINEWIDTHS IN LASERS

BEI NIANYU, LI XIAOSHEN

1986, 4(4):  361-365. 

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The linewidths of two-mode lasers in the three-level atomic system are obtained and discussed via the exterision. of Lamb's quantum theory. The present results reflecting the efifeots of mode coupling^ are odmpared with the early ones obtained by Biohter and Grossman.

SnO₂:F THIN FILMS WITH HIGH TRANSPARENCY AND HIGH CONDUCTIVITY PREPARED WITH SPRAY PYROLYSIS METHOD

WANG FUSHAN, LI PEIDE

1986, 4(4):  366-369. 

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Fluorine-doped conductive SnO₂ thin films with high transparency were prepared using spray pyrolysia method. Possessing high transparency and low resistivity, the thin films can be used as window materials in SIS solar cells, and back conductive materials in Cu₂S/CdS heterojunotion solar cells. The effects of technical parameters on the properties of the films were investigated. The optimum fabricating the transparent and conductive films was defined. When substrate temperature was 480℃ and fluorine concentration 1.5wt.%,the SnO₂ thin films possessed lower square resistance (8Ω/□) and higher transparency (at visible radiation more than 90%). Its merit factor 72×10^-3Ω^-1 (λ=550nm) proves it is of the advanced level of present days.

X-RAY CRYSTALLOGRAPHIC STUDY ON A NEW DRUG常咯啉

WANG PEIIJNG, LI DEYTJ, WU JIAN

1986, 4(4):  370-372. 

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常咯啉 is an antiarrhythmic drug with a new chemical structure formula synthesized by Institute of Medicine, Academia Sinica. The chemical formula is C₂₄H₂₉O₁N₅. It is a fiat pale yellow crystal. The crystal was investigated using Philips PW1100 model single-crystal four-circle diffractometer. The lattice parameters obtained are as follows:_a=21.94Å, _b=5.90Å, _c=12.97Å,β=99.60°.It belongs to the monoclinic system with a space group P2₁/c.

THE CC-DLTS SIGNAL ANALYSIS OF TWO KINDS OF CARRIERS EMISSION AND ITS APPLICATION

ZHAO LENGCHU, WU KEGIN

1986, 4(4):  373-376. 

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A new analysis is developed for evaluating the interface state parameters using CC-DLTS technique. Comparing with M. Schulz's theory, it has following features:(1) Measurement range can be extended into inversion region; (2) Interface state parameters of two kinds of carriers, majority and minority, can be extracted from the measurement.