Table of Content

31 March 1999, Volume 17 Issue 1

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Articles

A Smart Composite Structure System of Self-Diagnostic and Self-Adaptive Strength

TAO BAOQI, SHI LIHUA, XIONG KE, LIANG DAKAI, YUAN SHENFANG

1999, 17(1):  1-8. 

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A smart composite structure system with embedded sensors and actuators is developed to realize the function of self-diagnostic and self-adaptive strength. Sensory systems employing optic fibers and piezoelectric elements are investigated. A frame type Shape Memory Allory(SMA) actuator is designed. The smart system can identify loads and damages of the structure by using artificial neural networks and initiate adaptive control to the embedded SMA to improve the structural strength.

A Self-Adaptive Genetic Algorithm in Accelerator Cavity Design

YAN XIAOWEI, FAN MINGWU

1999, 17(1):  9-13. 

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We give a genetic algorithm which is used in the design of accelerator cavity. The algorithm is self-adaptive, that is, it can automatically adjust the genes in a chromosome during evolution according to the constraints on genes, and make the chromosome still belong to the same type structure of cavity.

Investigations of Silk Fibroin Electrochemical Immunosensor and Its Application in Clinical Analysis

PENG TUZHI, ZHU FANGMENG, YANG LIJÜ, CHENG QIONG, TANG TING, CHEN JIANYONG

1999, 17(1):  14-17. 

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In this paper, the preparation of silk fibroin and the ways of immobilizing antibody on silk fibroin are investigated for electrochemical immunosensor. Cross-linking after hydrochloric acid activation, diazo, azide and cross-linking after hydroxylamine activation method are tested for immobilization. In comparison of diazo and azide me thods, the best reponse is obtained when the silk fibroin is activated by hydrochloric acid. The silk fibroin immunosensor is sensitive when measuring α -fetoprotein and the detection limit of 5 μg/L is found. It showes linear response over the concentration range of 10~300 μg/L with correlation coefficient 0 9996. When it is applied to clinical sample analysis, the results are satisfactory.

Non-Stationary ARMA Modeling of Ship Radiation Noise

SONG AIGUO, LU JIREN

1999, 17(1):  18-25. 

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Modeling of ship radiation noise is an important issue of ship target classification. In this paper, the characteristics of ship radiation noise is analyzed, and a novel simple non -stationary ARMA model is proposed for modeling of ship radiation noise. The experiments of modeling of three classes of ship radiation noise recorded on the sea show that the proposed nonstationary ARMA model is correct as well as simple.

Design and Implementation of Global Security System in Open System Environment

QIN ZHIGUANG, LIU JINDE

1999, 17(1):  26-32. 

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Security is very important in open system enviroment because of the systems are easily subject to illegal operations and intentional attacks. In this paper, the open system enviroment based on the trader is introduced, and security requirement and architecture of global security system in the open system enviromemt are analyzed. A design of a global security system used for the open system enviroment is proposed and its prototype implementation is given.

A Linearizing and Decoupling Control Strategy and Its Applications

HANG CHENGHUI, WANG JUN

1999, 17(1):  33-38. 

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In cement production, the input/output model used to describe the static characteristic of raw material mixing system is nonlinear and coupling by interactive variables. Provides a linearizing and decoupling scheme and makes the system linearized and decoupled. It is very significant and convenient for analyzing, designing and implementing the control system. Designs an adaptive decoupling control system based on the improved weighting least squares method, realizes high-accuracy and stronger robustness control. Provides the results of simulation and practical operation and makes a comparison with the conventional adaptive control system.

A Kind of Dynamic Decoupling Method for Wrist Force Sensor

XU KEJUN, YIN MING, ZHANG YING

1999, 17(1):  39-44. 

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The dynamic coupling is a special problem in the investigations of multi-dimensional force sensor's dynamic characteristic. There is no effective method to solve the dynamic coupling so far. This paper proposes a constance dynamic decoupling method of sensor. Based on the dynamic calibrating experiments, the sensor's dynamic models are set up, the decoupling network is designed in discret domain. Both the constructed models and the wrist force sensor are decoupled, and good effects are obtained. The constance decoupling method is simple and practical, and is a new kind of method for solving key problem of other multi-dimensional sensors and compound types of sensors.

A New Method of Surface Temperature Sensor Dynamic Calibration and Transient Temperature Measurement Based on Neural Networks Identification

ZHOU CHUAN, HU SHOUSONG, MA QINDI, HU WEILI

1999, 17(1):  45-50. 

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In this paper, a kind of thin film thermocouple is designed for transient temperature measurement, and a new experimental scheme of temperature transducer dynamic calibration is presented. The mathematical model of transducer has been acquired using artificial neural networks identification. By many groups of experimental data, networks are trained to realized accurate dynamic calibration of transducer. It has been shown that the method presented in this paper provides reliable experimental results and new theory for transient temperature measurement.

A New Identification Method and Its Application for Nonlinear Systems

YAN JIHONG, SHI XIAOPING, WANG HONGWEI, WANG ZICAI

1999, 17(1):  51-57. 

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A new method is presented to identify the structure and parameters of nonli near systems in this paper. Because of the specialties of time-variable systems, an efficient on-line method for both criterion function and parameter identification is obtained by means of the recursive least square method with the forgetting factor, at the same time, the model structure is determined. To reduce the quantity of computation, the Cholesky factorization is used in model estimation, and the proof of the convergence of the algorithm is presented. The new method is applied to the on-line estimation of the F-8 Crusader aircraft longitudinal kinetics model. The results show that the models represented by polynomial and splint functions can be determined efficiently.

Petri Net Models of Grammars and Its Structure Algorithm

YAN CHUNGANG, JIANG CHANGJUN

1999, 17(1):  58-63. 

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In this paper, the Petri net models are established for right linear grammar, expression grammar and property tree formal grammar. The structure algorithms of these models are given and the properties of models are discussed. It is pointed to gene rate language process based on Petri net models by examples. So it is shown that the models are not only intuitional but also dynamic.

Robotic Ground-to-Wall Transition Programming with Real Constraints

QIAN JINWU, LUO YI, ZHANG YANAN, WU HUIXING, SHEN YAOZONG

1999, 17(1):  64-69. 

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The ground -to-wall transition programming of a multi-legged robot with actual constraints is more complicated than that with ideal constraints. After discussing the specific characteristics of actual constraints for a newly-developed leg -pad mechanism with three degrees of freedom, the so-called "virtual pad removal" and "virtual surface" concepts are proposed in order to simplify transition gait programming, and the goal function and influencing factors are discussed. By means of computer simulation of an actual example, the feasibility of transition motion strategy of alternating tripod gait with the robot's body centerpoint moving along elliptic trajectory is verified.

A High-Accuracy Algorithm for the Interpolated Displacement of Grating Signal

LIU WENWEN, FEI YETAI

1999, 17(1):  70-74. 

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In this paper, a high-accuracy algorithm for the interpolated displacement of grating signal is presented which based on Lissajous figure. The key of the algorithm is to separate and correct the DC level drift, the orthogonal error and the amplitude error from imperfect grating signal. As a result, the accuracy of the interpolated displacement of grating measurement system can be raised. Experiments and comparisons have proved the fact that the algorithm is correct and effective.

The Upper Bound Analysis of Section Extrusion Process

HUANG XIANG, ZHOU RURONG

1999, 17(1):  75-82. 

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An upper bound model for analyzing extrusion process is proposed. In this model, the deformation zone surface is constructed by interpolating the arbitrarily cross-sectional shapes of the billet and the section, the axial velocity distribution is considered in the admissible velocity field, the pseudo-independent parameters in the deformation zone surface and the admissible velocity field are calculated by optimum method. Analytical results show the upper bound method presented here is accurate, the calculating results are coincident with the experimental ones.

The Mathematical Model of Sperm Guidance System of Micropyle of The Teleost

WU KUNMING, SONG HUICHUN, SHEN QIZHANG, LIU GENHONG

1999, 17(1):  83-91. 

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After finding the whirlpool like structure of micropyle of the mature egg of Misgurnus anguillicaudatus in 1987, we discovered again that there is a radiate structure. This article establishs a general mathematical model of the teleost's micropyle by building a mathematical model of sectional curves of micropyle of Protosalanx hyalocranius, Megalobrama terminalis and studying the cause of the kind of curves. Because the conclusion that it saves work most that sperms travels along the micropylar camber. Thus further proving that exists unnegligible mathematical and physical dynamic factors besides the chemical explanation during the teleosts's sperm entering micropyle, which is mechanical impetus acts. Both sides bring out the best in each other and form a complete sperm guidance system of micropyle.

The Study for the Number of Reaction Coefficients in Method of Reaction Coefficient in Unsteady Heat Transmission of Wall

HE JIAPENG, LIU HUANCHENG, FANG XIANDE, WANG DONGFANG

1999, 17(1):  92-98. 

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According to building's characteristics of China, the walls are divided into three mass levels:heavy、middle and light from thinking of heat transmission. Using theory about unsteady heat transmission of wall and simulated calculation by computer, a definite value of numbers of reaction coefficients is proposed in this paper. Method of heat transfer reaction coefficient is perfected and a better condition is produced for use of this method.

Robust H^∞ Control of Rotor System with Structural Uncertainty

LUO ZHIMING, GU JIALIU

1999, 17(1):  99-102. 

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Based on the H^∞ control theory, a robust H^∞ controller was found out for rotor systems with uncertainty of mass and stiffness. For the model rotor system, simulation shows that robust H^∞ controller can rejected the imbalance response effectively.

Study on the Mechanism of Phase Separation of Non-Crystalline Materials

DUAN RENGUAN, LIANG KAIMING, GU SHOUREN, CHEN XUANLING

1999, 17(1):  103-107. 

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According to the classical theory of linearized spinodal decomposition kinetics and nucleation -growth kinetics, after a series of mathematical calculation, the following results were obtained. When the phase separation began to advance in the field of unstable(spinodal), there was not a regular relation between the size of non-uniform region and the time, but in the field of metastable(nucleation-growth), the square of the size of non -uniform region was in proportion to the time. The rightness of above results was tested by experiments in the related references.

A Theoretical and Experimental Study on the Perturbation of Solid Acoustic Resonator

CHEN GELIN, ZHENG HUAGE

1999, 17(1):  108-113. 

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Using acoustic signature for nondestructive testing (NDT), relation between peturbation and acoustic signature of resonator is studed. The resonance frequencies and the field shapes of samples with or without crack are calculated by finite element method(FEM). Corresponding experiments are carried out for comparison and the results are conformed well. All of this are guide for NDT with acoustic signature inspection.

The Reduction of Flow Noise by Low Surface Energy Coating

TIAN JUN, XUE QUNJI

1999, 17(1):  114-118. 

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This paper aims at predicting the levels of the boundary layer noise as a function of the speed and the frequency, which based on the results obtained by flow-noise studies performed with a rotating cylinder in the boundary layer of the test section of water tunnel. The coating containing rich low surface energy materials is a hydrophobic and porous material. The covered coating model provides low dispersive and polar components of surface energy by decreasing bonds between water and coating, thus, the flow noise of the covered coating model can be decreased by 4~18dB in 4~80kHz.

Oxidation Kinetics of Microcrystalline Fe₃Al

WANG YONGGANG, HE YEDONG, ZHU RIZHANG

1999, 17(1):  119-121. 

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The oxidation Kinetics of microcrystalline Fe₃Al was compared with that of normal grain Fe₃Al at 1000℃ in air. It was shown that the oxidation rate of microcrystalline Fe₃Al was heavily decreased. The oxidation kinetics of microcrystalline Fe₃Al failed to obey the parabolic law. It was suggested that the oxide scale turned into microcrystalline state since the nuclear probability of oxide was extremely increased. The short circuit diffusion through oxide scale was dominant. An expression, x⁴=kpt, has been derived for the oxidation kinetics of microcrystalline Fe₃Al based upon the model of short circuit diffusion.

The Conjugate Gradient-Fast Multipole Method(FMM) for Electromagnetic Scattering Problems

ZENG LIN, NI WEILI, XIAO YANMING

1999, 17(1):  122-126. 

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In this paper, CG -FMM is applied for the solution of RCS in electromagnetic scattering problems. Careful discussion is made on the RCS solutions for various 2 -D scatterers. Several parameters and the iterative terminate criterion have been presented. Comparing with other methods, this algorithm has more advantage when electrically large objects are concerned.