Table of Content

31 December 1988, Volume 6 Issue 4

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Articles

THEORY AND COMPUTATION ON FINITE DEFORMATION OF A COMPOSITE RADIAL TIRE

C. OUYANG, G. A. TANG

1988, 6(4):  283-287. 

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The finite displacement deformation of a composite radial tire is calculated by the FE method; the distortion effect of the meridian section of the tire[2] is especially considered and successfully simulated. The inflation pressure as a "following type" is also considered here. Finally the computational problem of such deformation is reduced to solve a set of nonlinear algebraic equations related to the strained configuration of the radial tire. By using a specially modified Newton's iterative method, the numerical results of the problem are obtained.

GIANT POLARITONS

SUN HONG, FANG JUNXIN

1988, 6(4):  288-294. 

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The numerical results of giant polariton (GP) dispersion relations for a coherent GP state are reported, based on a self-consistent calculation method. The results show that the energy gaps between the up and down branches of the GP dispersions shift downwards as the light intensity increases. The lowest light intensity to observe the GPs is estimated and the possible influences of GPs on intense light Hainan scatterings in optical fibers are discussed.

DOUBLE α PROFILE TRIPLE CLAD DISPERSION-FLATTENED SINGLE-MODE FIBER

LIN ZHIYUAN, LI ZHENHUA, DU BAILIN, XIAO TIANPENG, MA YIMIN

1988, 6(4):  295-299. 

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A theoretical model of double a profile triple clad fiber is proposed, with corresponding electromagnetic fields formulized. The chromatic dispersion, cutoff wavelength, mode field radius and tolerance of a structural design of dispersion-flattened single-mode fiber are calculated and discussed. Experiments have demonstrated an attenuation as low as 0.32 dB/km at the wavelength of 1.55μm.

AN ALGORITHM FOR EVALUATING THE SPECTRUMOF A RANDOM SIGNAL, AMPLITUDE MODULATED BY A DETERMINISTIC SIGNAL

CHEN MINXIU

1988, 6(4):  300-304. 

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A convolutional algorithm is used to simplify the evaluation of the spectrum of a random process of known power spectral density and amplitude modulated by a deterministic signal, especially, by a periodic signal. The spectra of the periodic burst QPSK baseband signal are evaluated as an example, and the results are compared with those of the traditional algorithm.

ELECTROMAGNETIC COUPLING BETWEEN A HALF SPACE AND A LOSSY CONDUCTING CAVITY THROUGH A SMALL APERTURE

MA BAILIN

1988, 6(4):  305-312. 

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The electromagnetic coupling of an incident wave through a small hole into a hollow lossy conducting cavity of arbitrary shape is investigated. Resonant conditions and possible degenerations are discussed. A simple method for evaluating resonant fields in the cavity and some measures for reducing the fields intensities are presented. Numerical examples are given.

CHAOTIC SYSTEM THEORY AND PSEUDO-RANDOM SIGNAL GENERATOR

YAO YONG

1988, 6(4):  313-322. 

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In this paper, a discrete system described by a one-dimensional map is constructed in terms of our thought on the mechanism of chaos. Theory and experiment (including the related function analysis, spectrum analysis, statistical test) both confirm that when λ=√3, the system is of infinite-periodicity, non-asymptoticity, and chaoticity. According to our opinion, a chaotic solution possesses its definite distribution, although it is very sensitive to its initial condition. In this paper our system is shown to have a uniform distribution. Thus we use it to design a random number generator. The numbers generated have good uniformity and independence. Moreover, we introduce the method of inverse transformation which makes the generation of random signals of strictly monotone and continuous distributions solved completely. The designs for the generators of pseudo-random signals with uniform distribution on[a, b], exponetial distribution e (λ, μ), β-distribution β(p, q) and Gauss distribution N(μ, b) are given. Statistical tests show our new design method is both pracficable and economical.

QUANTITATIVE PHASE ANALYSIS OF Nd-Fe-B ALLOYS BY MÖSSBAUER EFFECT

LI ZHENGWEN, PING JUEYTJN, MA EUZHANG, PAN SHUMING

1988, 6(4):  323-328. 

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The quantitative phase analysis of Nd₁₅ Fe_85-x(x=0, 2, 4, 8, 11) alloys have been studied by the Mössbauer effect. The effect of boron content on the phase construction which influences the magnetic properties of Nd-Fe-B alloys is discussed. It is found that the quantity of the tetragonal phase increases (x<8) with increase of the boron content, reaches the maximum at x=8, and then decreases (x>8). In the Nd₁₅Fe₇₇B₈ phase, which has optimal magnetic properties, the relative quantities of the tetragonal phase, the B-rich phase and the Nd-rich phase are 84.6%, 4.6% and 10.8% respectively. The remanence of the alloys was estimated from the data of the quantity of the tetragonal phase and magnetic moment orientation degree. The calcalated results accord with those of the experiments.

THE BRANCH MATRIX ALGORITHM FOR MICROCOMPUTER FITTING OF MÖSSBAUER SPECTRUM

HUANG JIANGSHUN, CHBN JUNMING, WANG GE

1988, 6(4):  329-334. 

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A new method, the branch matrix algorithm, for the computer fitting of Lorentzan's experimental spectrum is suggested. It is derived from the analysis of the modified interrelations among the peak parameters of the Lorentzan curve in the iterative process for the microcomputer fitting of the Mössbauer spectrum and the treatment of the matrix branching to the algebraic equations of the Gauss Newton algorithm. The experience on the fitting of the Mössbauer spectrum indicated that in comparison with the algorithm without matrix inversion (Slavic Algorithm) the branch matrix algorithm presented in this paper has a faster convergent speed, a near iterative time and a near occupied computer memory.

A PRACTICAL ALGORITHM FOR ASSEMBLING BLADES ON TURBINE ROTATOR

FU GUOYAO

1988, 6(4):  335-339. 

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For some optimization problems in which there are many independent variables, the typical optimization algorithm cannot be used, or it would take the computer quite a long time to work them out. However, usually the optimum solution is not required in practical engineering, only a good, satisfactory solution being sufficient for it. In line with the peculiarities of certain practical engineering problems, the algorithm to solve a satisfactory solution can be found, which proves, to be a very efficient method.
On the basis of the characteristics of turbine blades mounted on every stage of a rotator, a practical algorithm for assembling blades is introduced in this paper According to this algorithm, the resultant moment of the wheel will be very small so long as some pairs of the right and left blades are exchanged and some pairs of high and low blades are also exchanged. The algorithm can be easily programmed and worked out on a microcomputer.

DETERMINATION OF THE PARAMETERS OF NEWMAN EQUATION BY COORDINATES TRANSFORMATION

QIU DIRONG, LIN YINGJU, LI LIQUAN, FAN DEPEI

1988, 6(4):  340-344. 

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By coordinates transformation and calculation with the Least Square method, we can determine the parameters of the Newman equation which represents the back reflection pseudo-Kossel curve. From the parameters, the planar spacing d of the corresponding lattice planes can be calculated. In our experiment, the d {533} of a single crystal silicon is measured. The accuracy of measurement is about 8×10^-6nm. The experimental procedures and the principal sources of error are also discussed.

THE COMPARISON OF THREE CURVE-FITTINGMODELS AND THE EFFECTS OF THE WEIGHTFACTOR IN THE ANALYSIS OF EXAFS

ZHENG YU, GU CHANGXIN, HUA ZHONGYI

1988, 6(4):  345-350. 

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In the present paper, the effects of three curve-fitting models and the choices of the weight factor on the determination of the structural parameters in the data analysis of EXAFS are analyzed and discussed.

SELF-CONSISTENT CALCULATIONS OF ELECTRON STATES IN Si-nipi DOPING SUPERLATTICE

WANG ENGE, HUANG HELUAN

1988, 6(4):  351-356. 

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The electron states in Si-nipi doping superlattice have been calculated self-consistently by the local-density functional approximation. The rules of electron subband energies and corresponding wave functions depending upon free carrier concentration have been obtained. The excitation energies between the occupied and the nearest-neighbor unoccupied states-(01) subbands for low carrier concentrations are discussed. The forms of the electron density are described under the Hartree potential and fully self consistent potential. It is found that the influence of the free carrier exchange-correlation potential V_xc(z) on subband energies is small.

SOLITARY SOLUTION IN A MODIFIED HUBBARD CHAIN WITH FINITE LENGTH

XIAO JIAXIN, WANG XIANGQUAN, LIN JIATIH

1988, 6(4):  357-362. 

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The effect of electron-electron interaction on the transfer properties of a one-dimensional conductor has been investigated by many authors, using the modified Hubbard chain model with infinite length only. In this paper, we develop the finite length Hubbard model to investigate the effects of electron-electron interaction. The results obtained show correctly the effects of chain length and Hubbard interaction on the lattice form, charge density, etc. The result of Lindner et al. can also be derived by taking the chain length approaching infinity.

A STUDY ON LiNbO₃ CHANNEL WAVEGUIDE AND WAVEGUIDE PHASE SHIFTER

HAN XIAOYI, YANG JIALING, CHEN YIXIN

1988, 6(4):  363-366. 

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This paper gives the details of the fabrication and testing of the single-mode-LiNbO₃ channel waveguide and the waveguide phase shifter. A novel method for suppressing Li₂O out-diffusion in the Ti:LiNbO₃ waveguide is wsed. The experimental V₅ of the waveguide phase shifter is 5 v.

THE EFFECT OF INFRARED DIVERGENCE ON THEULTRASONIC ATTENUATION IN SUPERIONIC CONDUCTOR β"-ALUMINIUM

WANG YANGPU, WANG YAOJUN

1988, 6(4):  367-370. 

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A new interpretation of the broad asymmetrical attenuation peak observed experimentally in the superionic conductor β"-aluminium is given on the basis of the infrared divergent theory which was developed for the excitation and de-excitation processes of the correlated states in the conductor. Both true and apparent excited energies have been obtained rather simply.

CONTINUOUS LASER MIRROR FOR Nd³⁺:YAG LASER

DAI JIE, LIN BUZHENG, GU ZHENTAI

1988, 6(4):  371-373. 

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This paper reports on the technological development of the laser mirror used for the 1.32μm Nd³⁺:YAG continuous laser. The mirror can successfully restrain the 1.06μm laser oscillation so that the continous laser output in the range near 1.32μm is realized. The laser pulse output of the color center laser near 1.17μm has also been obtained.

A FAMILY OF SOLUTIONS FOR ONE DIMENSIONAL KdV-BURGERS EQUATION

ZHOU ZUWEI

1988, 6(4):  374-376. 

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When the form of the solution of one-dimensional KdV-Burgers equation is "simple wave", a family of analytical solutions of this equation is obtained through a suitable transformation. And it is believed that this belongs to the type of "shock wave".