Table of Content

20 May 1997, Volume 33 Issue 3

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Wavelet Detection of Jump Points and Its Application to Exchange Rates

WONG Heung,IP Wai cheung,LUAN Yihui,XIE Zhongjie

1997, 33(3):  380-385. 

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We propose a method for jump point detection by wavelets. The observation model is assumed to be a deterministic function with an additive stationary noise. The detecting method is applied to the daily exchange rate of the US Dollar against Deutsche Mark in the period 1989-08-01 to 1991-07-31. All the points detected by our method reflect very strong economic and political impacts.

The Influence of Antarctic Environment on Human Physiology and Psychology

XUE Zuohong

1997, 33(3):  386-393. 

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Introduced some changes in physiological, indocrine, immune and psychological activities under the influence of Antarctic environment on the Antarctic research members of China. It is indicated that the above respects may provide scientific basis for inproving their physiological and psychological adaptabilities as well as selection of the Antarctic staff.

The Influence of Antarctic Environment on Human Physiology and Psychology

XUE Zuohong

1997, 33(3):  386-393. 

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Introduced some changes in physiological, indocrine, immune and psychological activities under the influence of Antarctic environment on the Antarctic research members of China. It is indicated that the above respects may provide scientific basis for inproving their physiological and psychological adaptabilities as well as selection of the Antarctic staff.

Generating Approximate 3D Graphics of Implicitly Defined Functions

QIU Zongyan

1997, 33(3):  375-379. 

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An algorithm for generating 3D surface of functions defined implicitly by algebraic equations is given. Tetrahedron division of the space is used in the algorithm. The approximate surface of functions is formed by pieces which are obtained from each of the tetrahedrons. This algorithm is relatively ease to implement and very practical. The algorithm can also be used to generating contour surface from algebraic equations, or from a set of numerical data related to points in space.

A Hybrid Architecture Based on HMM/MLFNN for Speaker Identification

BAO Weiquan,CHEN Ke,CHI Huisheng

1997, 33(3):  359-367. 

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A hybrid architecture is presented, which is based on Hidden Markov Models (HMM) and Artificial Neural Networks (ANN). The HMM provides a good probabilistic representation for temporal sequences while the ANN has a powerful ability of static classification, so the integration of Multilayer Feed-forward Neural Networks (MLFNN) and HMM can give a good hybrid architecture for speaker identification. Unlike most of previous methods of hybrid HMM/MLP, this architecture needs only small amount of data for training and it is also good in generalization. Using this architecture, some experiments of speaker identification have been conducted with better performance than that of single HMM.

Preservation of Model-theoretic Properties of Modules when It is Fracted

WANG Hanpin

1997, 33(3):  368-374. 

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Viewing modules M_S^-1R over a fractional ring S^-1R of a ring R as modules M_R over R, It is proved that some model-theoretic properties of modules, such as purity, pure embedding, elementary equivalence, elementary embedding, are preserved. The relations of such properties between M_R and (S^-1M)_S^-1R are also considered.

Carrier Trapping Effects in a-Si:H Schottky Barrier Structure
A Study of Stability in a-Si:H Solar Cells

LIN Hongsheng

1997, 33(3):  346-353. 

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On the basis of experimental results, a computer analysis model has been developed using a numerical solution of Poisson's equation for a hydrogenated amorphous silicon (a-Si:H) Schottky barrier structure subjected to light soaking. The calculations agree with experimental results and further indicate that due to carrier trapping with light soaking, the increased or decreased space charge density changes electric field distribution and leads to a wider quasi-neutral region (low field "dead layer") in the structure, resulting in reduced carrier collection length. This is an important cause of light-induced degradation of a-Si:H Schottky barrier solar cells. Thus, a new way to improve the stability of a-Si:H solar cells may be proposed.

Research on Microwave Remote Sensing of Atmospheric Water

HU Chengda

1997, 33(3):  354-358. 

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Ground based observation of atmospheric emission in the microwave band may be used to measure atmospheric parameters such as temperature profile or concentration of water vapour, liquid water, ozone and other atmospheric trace gases. By using atmospheric noise reception of 1.35cm water vapour absorption band and 8 mm window region, we could obtain the atmospheric total water vapour content and liquid water content in cloud. In this paper by way of calculating atmospheric radiation brightness temperature at four microwave bands it could be demonstrated that the 3mm band have more sensitive to the water vapour content and liquid water content than 1.35cm and 8mm bands especially for the water vapour content in clear sky. Consequently developing 3mm band radiometry is advantageous to remote sensing atmospheric water. Continuous measurements with high accuracy are important in determining forecasting on the mesoscale and heat balance in climatology.

Near-field Optics and Near-field Microscopy: the Basic Principles and Their Applications

ZHU Xing

1997, 33(3):  394-407. 

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The revolutionary development of scanning probe microscopy has made the imaging of objects at molecular or atomic level possible. With the discoveries of new physical phenomena at low dimensions, the near-field scanning optical microscope (NSOM) jointed the family after the scanning tunneling microscope (STM) and the atomic force microscope (AFM). Based on the common principles of non-radiating field, NSOM opened the possibilities of ultra-high optical resolution which overcomes the Rayleigh diffraction limit, and the optical spectroscopy at the nanometer scale. This review article discusses the basic principles of near-field optics, the relationship between non-radiative detection and high spatial resolution, optical confinement on small objects, the importance of evanescent wave as well as the methods to obtain the near field information. The NSOM related instrumentation is introduced. The application of NSOM in super-resolution optical imaging; high density data storage; near-field spectroscopy on single molecules, quantum devices, and the combination of NSOM with ultra-fast optical transient phenomena are summarized.

Near-field Optics and Near-field Microscopy: the Basic Principles and Their Applications

ZHU Xing

1997, 33(3):  394-407. 

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The revolutionary development of scanning probe microscopy has made the imaging of objects at molecular or atomic level possible. With the discoveries of new physical phenomena at low dimensions, the near-field scanning optical microscope (NSOM) jointed the family after the scanning tunneling microscope (STM) and the atomic force microscope (AFM). Based on the common principles of non-radiating field, NSOM opened the possibilities of ultra-high optical resolution which overcomes the Rayleigh diffraction limit, and the optical spectroscopy at the nanometer scale. This review article discusses the basic principles of near-field optics, the relationship between non-radiative detection and high spatial resolution, optical confinement on small objects, the importance of evanescent wave as well as the methods to obtain the near field information. The NSOM related instrumentation is introduced. The application of NSOM in super-resolution optical imaging; high density data storage;near-field spectroscopy on single molecules, quantum devices, and the combination of NSOM with ultra-fast optical transient phenomena are summarized.

Some Results on a Counting Process Associated to Records

QI Yongcheng

1997, 33(3):  289-297. 

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Let {I_n} be a sequence of the record indices, i.e, I_n, n≥1 are independent with P(I_{n>=1)=1-P(In=0)=1/n for n≥1, and set u(n)=Σⁿj=1Ij, n≥1. The probabilities P(|u(n)-logn|>εlogn) and P(u(n)=k) for some k's are inverstigated in the paper.}

Stability Analysis of Periodic Solutions of Dynamical Systems in Arclength Parametrization

ZHENG Zuochang,WU Jike

1997, 33(3):  315-318. 

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We discussed the stability of periodic solutions of dynamical systems in both time and arclength parameterization, and prove the variational equations at hyperbolic periodic solutions of the two kinds of dynamical systems have the same Floquet multipliers.

Harmonic Oscillator with Variable Mass under the Action of a Harmonic Driving Force

WANG Wei,GU Zhiyu,MIAO Chunhui,QIAN Shangwu

1997, 33(3):  333-339. 

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According to the general analytic expression of the wavefunction recently derived by Gu and Qian, we obtain the time variation of the probability density for three kinds of the variable mass harmonic oscillator under the action of a harmonic driving force .

Pipeline Leak Detection Method and Instrument Based on Neural Networks

TANG Xiujia,YAN Dachun

1997, 33(3):  319-327. 

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The mechanism of the stress wave propagation along the pipeline caused by turbulent ejection from pipeline leakage is researched. All of the longitudinal, transverse and circumferential eigenmodes caused by pipeline leakage are analyzed. A series of characteristic index are described in time domain or frequency domain, and compress numerical algorithm is researched for original data compression. A back propagation neural networks (BPNN) with the input matrix composed by stress wave characteristics in time domain or frequency domain is first proposed to classify various situations of the pipeline, in order to detect the leakage in the fluid flow pipelines. The capability of the new method has been proved by experiments and finally used to design a handy instrument for the pipeline leakage detection.

Postdeposition Resistance Relaxation of Semicontinuous Metal Films

WU Junqiao,WANG Zhijun,WU Ke,ZHANG Jinlong,LI Chuanyi,YIN Daole

1997, 33(3):  340-345. 

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Semicontinuous niobium and silver films were made in an ultra high vacuum(UHV) chamber and in situ DC resistance measurements were performed. Interrupting the deposition, the immediate aging phenomenon (relaxation) of the sample resistance was investigated in a time scale of about 10 minutes. Resistance increase and decrease were observed for niobium and silver samples respectively. The intensity of the relaxation is sensitive to substrate temperature and film thickness. The edge diffusion and coalescence of islands due to thermomigration of the metal atoms are probably responsible for the resistance relaxation.

Spillover Analysis and Simulation for Distributed Piezoelectric Element Method

SUN Dongchang,WANG Dajun

1997, 33(3):  305-314. 

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The observation and control spillover problems of Distributed Piezoelectric Element (DPE) method for active control of smart beams are analyzed and their improved methods are presented. Also, the numerical simulation result for DPE method is given.

Large Sample Properties of Estimation of the Error Distribution in Nonparametric Regression

YANG Ying

1997, 33(3):  298-304. 

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We investigate the asymptotic normality and the rates of convergence for the estimators of error distribution function and its density function for the nonparametric regression model.

Harmonic Two spheres in CPⁿ with Antipodal Symmetry and Complementation

MO Xiaohuan

1997, 33(3):  273-281. 

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Characterizations are proved for those harmonic maps from S² into CPⁿ or RPⁿ with few higher order singularities to be antipodal symmetry and complementation, using properties of directrix curves.

On the Inversion of a System of Linear Differential Polynomials

CHUANG Chitai

1997, 33(3):  283-288. 

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In a previous work we have proved an inversion formula for a linear differential polynomial, which has interesting applications. In this paper we investigate the case of a system of linear differential polynomials and prove, by a different method, a system of inversion formulas which contains the above mentioned inversion formula as a particular case, and of which we shall give an application.

Separation of Variables Treatment of the Time-dependent Coulomb Potential and Time-dependent Hulthen Potential

QIAN Shangwu,MIAO Chunhui,XIE Guoqiang,GU Zhiyu

1997, 33(3):  328-332. 

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For treating time-dependent systems, a new method based on separation of variables and time-dependent redefinition of the spatial coordinate has been developed by C.J. Efthimiou and D. Spector. In this article, we apply it to obtain the wave-functions of the time-dependent Coulomb potential and the time-dependent Hulthen potential.