Table of Content

30 September 1994, Volume 12 Issue 3

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Articles

NONPROPAGATING SOLITONS IN NONLINEAR LATTICE SYSTEMS

LIANG CHANGHONG, GUAN BORAN

1994, 12(3):  189-195. 

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The phenomenon that the nonpropagating soliton is a form of soliton existing in the nonlinear lattice system is discussed in this paper. The concept of collision of solitons is used to explain the phenomenon. The pure nonpropagating lattice soliton condition is presented,and the examples of numerical simulation are glven.

STUDIES ONN PASSIVATING A P₂S₅/NH₄OH-TREATED GaAs SURFACE

ZONG XIANGFU, WENG YUMIN, LID KEIFENG, FAN ZHINENG, LI CHAN, PAN ZONGWEI

1994, 12(3):  196-202. 

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The effect of P₂S₅/NH₄OH treatment on the (100) surface of GaAs was studied by X-ray photoelectron spectroscopy (XPS),Auger electron spectroscopy (AES) and photoluminescence (PL).The results show that after passivation the native oxide of GaAs Surface is completely removed and a passivation layer mainly composed of As-Sand Ga-Sbonds forms on the sample surface,and prevents the adsorption of oxygen. This concluson has been supported by results of PL experiments.The PL intensity and its contrast obtained on GaAs surface depend on the surface recombination and they are controlled by passivation. The results of PL experiments show the reduction of surface recombination and of the density of surface states P₂S₅/NH₄OH treatment is more stable than the others,such as Na₂S.

INFLUENCE OF THE MICROSTRUCTURE OF Nb₂O₅-DOPEDNiZnNc FERRITES ON THE ELECTRICAL AND MAGNETIC ROPERTIES OF THE FERRITES

CHEN YAJIE, GAO WEIJIAN, JIN ZONGHING

1994, 12(3):  203-208. 

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This paper investigates the effects of dopant on sintering and the properties of NiZnCu ferrite. There are marked changes in the microstructures of Ni_0.3Zn_0.7Cu_0.04Fe_2.04O_4+δ doped with various Nb₂O₅ contents.It is possible that the change in the microstructure is the main reason for the variations of other properties.The-experiments reveal that Nb₂O₅ can improve the sintering process and protect the-grain from enormous growth, Nb⁵⁺ ion can influence the lattice parameter,resistivity, density, initial permeability and magnetic loss.

SYNTHESIS OF AL AND AL-Y FILMS BY IBED TO IMPROVE THE OXIDATION-RESISTANCE OF 304 STAINLESS STEEL

LI HUALONG, HUANG YUANWEI, ZHANG YUNSRU, LIU XIANGHUAI

1994, 12(3):  209-217. 

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Al and Al-Y films were synthesized on the surface of 304 stainless steel by ion-beam-enhanced deposition (IBED).The isothermal oxidation behavior of the Al and Al-Y deposited 304 stainless steel was studied in air at 950℃and 1050℃,and their cylcling oxidation behavior was studied in air at 950℃.The experi-mental results indicated that the synthesized films enhanced remarkably the oxidation-resistance of the 304 stainless steel,and that the addition of Y improved further the eycling oxidation-resistance of the steel.SEM,AES,EPMA,and X-ray diffractions were employed tO characterize the oxidation products.On the basis of the results,the beneficial effects of Al,and in particular,of Y werebriefly discussed.

RESEARCH ON COUPLING LOSS BETWEEN THE SINGLE MODE OPTICAL FIBER AND THELINbO₃ WAVEGUIDE

SHEN QISHUN, GONG XIAOSHENG, QU WENYONG

1994, 12(3):  218-222. 

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In this paper we investigated the influence of mismatch between the fiber and waveguide modes on the fiber-waveguide coupling loss. We measured the wavegu-ide mode width and depth versus the metal Ti strip width.By determining the appropriate waveguide parameters,it is found that the coupling loss between the fiber and waveguide is very low.

RAMAN SPECTRUM ANALYSIS OF STRESS DUE TO SILICON DIRECT BONDING

HUANG QINGAN, ZHANG HUIZHENG, CHEN JUNNING, TONG QINYI

1994, 12(3):  223-226. 

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A method of measuring the stress in silicon with the Raman spectrum is introduced. The stress due to silicon direct bonding is studied using the spectrum.It has been shown that there exists local tensile or oompressive stress in bonded silicon after high temperature bonding.The stress is as large as 7.5×10³N/cm².

RESEARCH ON FORMING THE FILM OF AMORPHOUS SUPERLATTICE MULTILAYER STRUCTUREAND ITS PHOTOPROPERTIES

WU DINGXIANG, XU KEXI

1994, 12(3):  227-232. 

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In this article the photochemical reaction is introduced by using ArF excimer laser of wave length 193nm to decompose the feed gases Si₂H₆ and C₂H₂ for fabricating the a-Si:H/a-SiC:H film of the amorphous superlattice multilayer structure. The photoproperties of the quantum size effect,the ultraviolet absorption,etc of such a film are discussed.

THE STRUCTURE AND STABILITY OF LAMELLAR LIQUID CRYSTAL WITH SHORT CHAIN ALCOHOL

GUO RONG, YAN PENGQUAN, ZHU XIASHI, SHEN MING

1994, 12(3):  233-238. 

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We found it possible to form the lamellar liquid crystal using alcohol with short chains as a cosurfactant in SDS/C_nOH/H₂O systems,the stability of the lamellar liquid crystal increased with the chain length of alcohol.The increase of interlayer spacing d with the chain length of alcohol was related to the d₀ value and the penetration of solvent in the lamellar liquid crystal.

STUDY ON THE FORMING PRINCIPLE AND CONTROL TECHNOLOGY OF FORWARD BURR

WANG GUICHENG

1994, 12(3):  239-245. 

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This paper classified the forms of forward burrs in metal cutting on the basis of the cutting motion and tool outting edges.The principles of forming and the main influencing factors of forward burr are studied,and the related theories are analyzed.Thus a clear understanding of the types, and the forming process of the burrs is obtained. The physical quantity of determiuing the tear of forward burr-limit depth of cut α_pr-is given. A oertain number of measures and new restraining methods to control and decrease the forward burrs are advanced.

THE CONNECTION METHOD WITH EQUALITY FOR AUTOMATED THEOREM PROVING

MIAO HUAIKOU, WU MAOKANG

1994, 12(3):  246-252. 

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This paper diseusses the connection method with equality in automated theorem proving.The formal definitions are given. The theorem that a logic formula with equality is eq-valid if and only if it has a complementary formal matrix of a compound instance is proved,and several algorithms about the connec-tion method with equality are designed.

B-P LEARNING ALGORITHM OF NEURAL NETWORK AND ITS APPLICATION TO THE SYNTHESIS OF HIGH-T_c SUPERCONDUCTOR Bi-BASED DOPED F

CAI YUDONG, LIU HONGLIN, GAN JUNREN, YAO LINSHEN, CHEN NIANYI

1994, 12(3):  253-258. 

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Great attention is now being paid to neural network in pattern recognition and other fields. The structure of neural network,the back propagation algorithm for neural network and its application to the synthesis of high-T_c superconductorBi-based doped F are presented in this paper.The experimental results show that the performance of the neural network model is good,and therefore the model may be used in material design and other fields.

ERROR SENSITIVITY ANALYSIS AND CORRECTION FOR SURFACE NORMALS DETERMINED BY PHOTOMETRIC STEREO METHOD

YANG JINGAN

1994, 12(3):  259-266. 

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The surface orientation of a 3-D object in a scene can be determined by the photometric stereo method without the need of complicated computation,but this method is susceptible to a number of errors.In this paper, we not only discuss and analyse several kinds of major errors, but propose a new algorithm for error sensitivity analysis.This new one leads to a mush simpler derivation process and substantially rigorous sensitivity formula.It is demonstrated that the experimental results are fully consistent with the photometric stereo theory.

A CURVILINEAR INTEGRAL METHOD TO SOLVE PLANE DRAWING AND EXTRUSION THROUGH HYPERBOLIC DIES

ZHAO DEWEN, FAN HEFENG, ZHAO YING

1994, 12(3):  267-272. 

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The kinematically admissible velocity and strain rate fields for drawing and extrusion through a hyperbolic die are established in this paper.The curvilinear integral and the integral as a function of the upper limit are used for obtaining friction and deformation powers.An analytical solution of mean plane extrusion and drawing stresses is obtained for hyperbolic dies.

KNOWLEDGE DESCRIPTION STRUCTURE IN ICAI SYSTEMS AND THEIR DEVELOPING TOOLS

GUO RUIBIAO

1994, 12(3):  273-279. 

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This paper first analyses all kinds of knowledge description structures and their limitations in the existing Computer Assisted Instruction (CAI) and Intelligent Computer Assisted Instruction (ICAI) systems.Then it makes a new classification of the knowledge components in ICAI systems. The article, on the basis of the above-mentioned,gives a general knowledge description structure model which may cover various types of ICAI systems,support every teaching pettern and include all kinds of knowledge components in ICAI.

EXPERIMENTAL STUDIES OF PILOT HEAD IMPACT FOR THE MODEL TRAUMA

WANG YIJIN, LI WEI, SU JIANLIANG, WENG SHENGLONG, WU GUIRONG, ZHANG YUNRAN, WANG YUQING, YOU GUANGXING

1994, 12(3):  280-286. 

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The objective of this study is to perform experiments on the heads and necks of 34 rhesus monkeys so that a valid analytical model can be made for the impact situation to determine the skull-brain injury tolerance in the animal tests. When the skull-brain is impacted directly, the brain deforms and the skull internal pressures increase at the site of local skull deformation. Such knowledge would be helpful in the treatment of injury through identifying the mechanism of trauma and in protecting the pilot during ejection.

EMF MEASUREMENTS AND CALCULATIONS ON Na|β-Al₂O₃|Na_xHg_1-x(LIQUID)CELLS

SUN CHENGWEN, CAO YONGXU

1994, 12(3):  287-294. 

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Sixty-eight sodium amalgams Na_xHg_1-x (x:0. 035~0. 8846) are prepared using the Na|β-Al₂O₃|Hg solid electrolyte cells. The melting points of Na_x Hg_1-x, and the entropy and enthalpy changes of the cell reactions in the melting procets aredetermined from EMF measurements on Na/Na_xHg_1-x cells, Experimental results show that the relatiodship between the EMF and sodium molar fraction x in the Na/Na_xHg_1-x(liqui) cells may be expressed as E=a (-lgx)_b. For the ranges of x:0.06~0.16,0.16~0.333,0.333~0.715 and the different temperature ranges,the lga and b in the relation of lgE=lga+blg (-lgx) are obtained which are linear functions of the temperature.

CALCULATION OF THE PARAMETERS FOR MULTIPASS ONE-STAND-TANDEM MILL IN CROSS SHEAR PALLING

YAN YINGHUI, YUAN LI

1994, 12(3):  295-303. 

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The paper discusses q_h and q_H relations between any two passes in the one-stand-tandem mill,and proposes a way to calculate any pass's P(x),P,h_c and h_b (or h_H) on Pv rolling,IPV rolling and normal rolling. Tan's 350 three-pass one-stand-tandem mill's experimental data are used to calculate the above parameters.The results show that the total pressure P is the smallest in PV rolling and the greatest in normal rolling

CALCULATION OF THE VIBRATIONAL DENSITY OF STATE OF ZrF₄-BASED CLASSES

GAO ERZHEN, GU SHIWEI

1994, 12(3):  304-306. 

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The vibrational density of state (DOS) is culculated for the possible microstructures of ZrF₄ which is obtained with the MD method. The results are consistent with the experiments and useful in studying the loss of infrared of the ZrF₄-based glasses.

THE MEASUREMENT OFCRYSTALLITE SIZE AND LATTICE DISTORTION FOR α-Fe₂O₃

WANG MEISHENG, ZHANG QIONG, JIANG JISEN

1994, 12(3):  307-310. 

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This paper reports the measuring principle and results of crystallite size and lattice distortion for α-Fe₂O₃ with the broadening method.The measurement is made with a Y-2 X-ray diffractometer. The quartz is taken as the standard matter.Three different sizes of α-Fe₂O₃ are measured.Results show that the spectum lines broaden and lattice distortions increase as the crystallite size decreases.

THE OPTIMIZATION OF THE PROCESS AND PRESCRIPTION OF Nd-Fe-B ALLOY USING PLS REGRESSION

LI MING, XU CHI, CHEN NIANYI

1994, 12(3):  311-314. 

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With the partial least squares (PLS) algorithm,the optimization of the process perameters and prescription data of sintered Nd-Fe-B permanent magnets,colle-cted from a factory, is demonstrated in this paper. The project includes decreasing the temperature and humidity of the environment during the rough smash process,slowing down the speed of the class wheel, lessening the ratio of Nd and B,and adding some Ti,etc. The conclusions have been corroborated by experiments and documents They are reasonable and of practical significance.