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2001 Vol. 27, No. 3

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Research of Polyetheretherketon and Zirconium Dioxide Solid Alloy
ZHAN Mao-sheng, LI Jian-ping, LI Yu-bin
2001, 27(3): 249-253.
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The compound of polyetheretherketon (PEEK)/zirconium dioxide (ZrO2) was distorted, fractured, and welded together, and the new phase was formed through the diffusion of all kinds of atoms of components, in high energy rotating ball mill at temperatures below the glass transition temperature of PEEK, that is to say, the solid alloy of PEEK/ZrO2 was formed. The structure and physical properties of the polymeric alloy, whose formulas were 1/2 and 2/1, were investigated, by means of SEM, DSC, IR and DMTA. By contrast with pure PEEK, the possibility of mechanical alloying of PEEK and ZrO2 was explored. The effect of the process of mechanical alloying on the properties of PEEK/ZrO2 solid alloy was discussed, and the mechanism of mechanical alloying was analyzed.
Synthesis of Electron Beam Curing Resins
LI Min, ZHANG Zuo-guang, ZHONG Wei-hong, YAO Hong-wei
2001, 27(3): 254-256.
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The use of electron beam (E-Beam) radiation to carry out rapid, pollution free, low energy crosslinking polymerizations of multifunctional vinyl monomers is an established technique. Polyimides and maleimides possess many useful properties such as high use temperature, excellent dimensional stability, low dielectric constants, and outstanding thermal and thermo-oxidative stability. Polyimides cured by electron beam radiation are conducted. In this work, to meet the requirement of electron beam curing polymerization, sensitive groups were introduced to monomers. Furthermore, the active diluents of siliceous acrylate, maleimide monomers and the aromatic imide monomers were synthesized. All of them were characterized by FTIR, so as the cured materials.
Research Advance on Bridge Function and Generalized Bridge Function
ZHANG Qi-shan, WANG Gang
2001, 27(3): 257-259.
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Bridge Function and Generalized Bridge Function are all three-valued function,and are made by initial sequence according as copied or shifted ways.They include some familiar orthogonal function of non-sine,such as Walsh Function.This paper briefly introduced some research advance on this subject,emphasized to introduce the copy theory and generalized copy method.The process of making (Generalized) Bridge Function,its property and application, were introduced briefly.
Design and Implementation of a Real Time Network Communication Software Based on IPX Protocol
KUANG Wei, ZHANG Xiao-lin, CUI Ying-wei, ZHOU Xiang-r
2001, 27(3): 260-263.
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In order to meet the requirement of real time communication capability of certain Novell network, a real time network communication software IPXSR based on IPX protocol was developed. Firstly the principles of real time communication programming technology based on IPX protocol is analyzed. Then the design ideas, characteristics, implementation technology of IPXSR are discussed. Now this software is authenticated and accepted, working well in for nearly one year. It can also be replanted into other physical networks.
Research on Coning Compensation Algorithms for SINS
WANG Yang-zhu, CUI Zhong-xing
2001, 27(3): 264-267.
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High speed and accuracy coning compensation algorithm plays an important role in strapdown inertial navigation system(SINS) in high dynamic environment. To reduce the effect of coning error, a deep research on design of coning compensation algorithm and character of coning compensation error is made. The angular rate vector of pure coning motion is given at first, then the incremental attitude vector, the cross product of two incremental attitude vector and the equation of coefficients are derived. Twenty-one types of coning compensation algorithm are obtained by this means. The computer simulation is taken to give the character of coning compensation algorithm and the result is shown in the end.
Autonomous Position and Orientation Method for Space Mobile Robot
LIU Xin, ZHANG Chang-yun, SHEN Gong-zhang
2001, 27(3): 268-271.
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Aiming at the space mobile robot employed in lunar exploration, the scheme of strapdown inertial navigation on tangent plane, the position and orientation method using computer vision are studied in this paper. Also a new inertial/computer vision integrated navigation system is proposed. Static and dynamic algorithms of the integrated navigation system are given. In this system, high precision of navigation is gained while the robot is required to carry fewer devices, which can cut down the cost. Result of simulation is shown at the end of the paper.
Method of Error Compensation for Inertial Elements Based on Fuzzy Optimal Algorithm
ZHANG Fei-zhou, FAN Yue-zu, SUN Xian-fang
2001, 27(3): 272-275.
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The method of error compensation for inertial elements in navigation system based on fuzzy optimal algorithm is presented. Its essential idea is combining genetic algorithm (GA) with fuzzy logic reasoning, preserving strong whole searching capability of GA and acting membership function as genetic individual. Consequently, the fuzzy rules are optimized by means of selection, crossover and mutation operation and so on, realizing the optimization of fuzzy rules on line. And then on the basis of optimized fuzzy rules, the genetic operation and parameters are adjusted on line again and the fuzzy rules are further optimized, which makes fuzzy control system have good self-evolution capability. The simulation results demonstrate that the fuzzy optimal method has certain validity and feasibility for error compensation of inertial elements in navigation system, it has better practical worth.
Measurement Quality and Performance Enhanced by the Pictorialized Measurement
HUANG Jun-qin
2001, 27(3): 276-279.
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The pictorialized measurement in the modern aircraft instruments is introduced in order to describe the enhancement of measurement quality and performance by the pictorialized measurements. The more deeper problems can be solved in more higher level describing the measurement results by using the pictorial display with computer. The composition block diagram of the pictorialized measurement system is presented in this paper and then the applications of pictorialized measurement in a lot of industrial and research departments are proposed in order to enhance the measurement quality and performance. Finally, some progresses of the pictorialized measurement are illustrated by some examples.
Simulation about the Conditioning Circuit of Sensor
LI Nan, Lü Jun-fang, LI Yu-tao, YUAN Mei
2001, 27(3): 280-283.
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In testing system, measuring small signals is necessary. The conditioning circuit is a crucial section, and its reliability has a great influence on the whole testing system. By using the method of computer simulation and thermal analysis, the functions of the circuit can be simulated and relevant parameters can be optimized previously to promote the circuit-s capability. By this means, the research time can be dramatically shortened and the expense can be more less. Therefore, these methods have a great value in practice.
Fault Diagnosis of DC Motor Based on Parameter Estimation and Fuzzy ARTMAP
YANG Jing, LIU Xiang-qun, ZHANG Hong-yue
2001, 27(3): 284-288.
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In order to improve the motor quality and realize system monitor, a new approach to diagnose motor faults is presented to estimate the electromechanical parameters of motor based on the block-pulse function series and classify motor faults based on Fuzzy ARTMAP neural network. The electromechanical parameters of motors can be acquired on line without stopping and loading motor. Thus therunning state of motor is obtained. Because of the strong pattern recognition ability of Fuzzy ARTMAP neural network, it is employed to diagnose the type and magnitude of faults. The effectiveness of the proposed method is verified by the results of simulations and experiments.
Further Assessment of the NO x Emission from CAAC Fleet over China
HUANG Yong, WU Dong-ying, WANG Jin-tao, WU Shou-sheng
2001, 27(3): 289-292.
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On the basis of CAAC timetable and route setting, and according to individual aeroplanes and aeroengines, the present paper simplified and modeled the operation of each flight. Moreover, using the popular fuel flow method and by means of the emission databanks published by ICAO and NASA,the inventory of NOx emitted from CAAC flights in April to October of 1998 was assessed. The results show that NOx emissions from current commercial airplanes over China are concentrated on some big cities. The concentrations of NOx over different cities have great differences. The NOx emissions over China have doubled comparing with 6 years ago. And the NOx emission level over several Chinese big cities is about the same as that of some big cities in developed countries at 6 years ago.
Research on Parameter Selection of Low RCS Serrated Pylon
HUANG Pei-lin, MA Dong-li, WU Zhe
2001, 27(3): 293-296.
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Wing and pylon form a structure which is the major lateral scattering sources of an ordinary aircraft because a dihedral angle of ninety degrees is formed. In order to implement a reduction of RCS without any other change on the aircraft, the outline of the pylon is changed by applying a serrated scheme and the right dihedral angle structure is removed, so coupling effect is waken. Computation results reveal that the RCS of the wing-pylon structure on a domestic active fighter plane is reduced by 9 to 13 dBsm in the typical lateral attitude angle range. So it is proved that the serrated scheme could be significant useful in the control of the lateral coupling RCS of the ordinary aircraft. The ray trace method is used to do the calculation of the RCS.
Effects of Rotor Downwash on Engine Jet
SU Yuan, WANG Ji-fei, CAO Yi-hua, CHEN Jiang-feng
2001, 27(3): 297-300.
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An analytical method to predict the effects of rotor downwash on engine jet was proposed to investigate the flow pattern of helicopter engine jet. First, free wake analysis was carried out to calculate the rotor wake geometry and the downwash around the engine jet space. Then engine jet path, cross section shape and physical variants were calculated and analysed. Finally, an example was given to show that the method can be used to predict temperature distribution of a helicopter.
Object Oriented Finite Element Modeling Expert System
XU Yuan-ming, GONG Yao-nan
2001, 27(3): 301-304.
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An Object Oriented Finite Element Modeling Expert System (OOFEMES), developed by combining the principle of object oriented programming and logical based reasoning is presented. The design and implementation of system function and structure are emphasized, which include the classification, organization and representation of domain knowledge, as well as the associated reasoning and computation techniques. A model correction diagram, taking into consideration the structural irregularity of aircraft structure is given. Through application example, it proves that the developed system is useful and effective for the analysis of aeronautical structures.
Quantitative Thermal Design of Heat Sinks in Large Space Simulators
JIANG Chuan-sheng, WANG Jun
2001, 27(3): 305-308.
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The main factors influencing heat sink wall temperature distribution of large space simulators are analyzed. Fin-tube flow rate allocation of heat sinks with different structures are studied with heat sink dynamic simulation software HSDS. Simple and feasible improvements as for thermal design are made to promote the performance of the heat sinks in a large space simulator. Finally, the typical procedure to perform quantitative thermal design of heat sink with HSDS is provided.
Study on Type and Sizing Tariff of Aircrew Oxygen Masks
WANG Xing-wei, YUAN Xiu-gan
2001, 27(3): 309-312.
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In order to design high performance oxygen masks, the factors which affect the hermetization and comfort of mask are studied, and it is pointed out that sizing tariff is one of the most important factors. Human engineering principles of mask type and sizing tariff are discussed based on fighter pilots' face characters and their ideas and opinions about masks, and a new sizing tariff project is founded. The result can be applied to the design of new high performance oxygen masks.
Investigation of Aerodynamic Characteristics of Vee Tail
KONG Fan-mei, QIU Dong
2001, 27(3): 313-316.
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Experimental investigation of the aerodynamic design of the vee tail featuring low RCS has been carried out. The effects of the wing dihedral angles, and aileron positions on the aerodynamic characteristics of the complete aircraft with vee tail are studied. Aircraft models with two types of vee tail and two conventional tails have been tested and the longitudinal/lateral performances compared. The results show that off-shipping moment curves are caused nonlinear by the wing with dihedral, and that the same order of off-shipping efficiency of aileron as that of its rolling efficiency is caused by the deflection of inboard aileron. Therefore, it is an important criterion that vee tail should avoid the effect of the asymmetric downwash in aerodynamic design.
Vibrational Nonequilibrium Distribution of Diatomic Molecules
ZHANG Jin-bai, LI Chun-xuan
2001, 27(3): 317-320.
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An attempt is made in the present paper to develop an analytical model to modify the Hammerling-s hypothesis in dealing with the vibration modes for diatomic molecules under nonequilibrium states. The characteristics of distribution functions for vibration modes of diatomic molecules undergoing a nonequilibrium relaxation process are studied and a new approximate form of distribution functions is proposed. The calculations of test cases show that the majority of the characteristics of the vibration modes can be represented by the deduced approximate function. The utilization of the formulation on computations of the rate of the N2 dissociation undergoing a nonequilibrium relaxation process has demonstrated to be successful, and the study also partly verify the theory behind Park-s two-temperature model.
Calculation and Analysis of the Flow Passing through a Multi-Element Wing
WU Zong-cheng, ZHU Zi-qiang, LI Jin, CHEN Ze-min
2001, 27(3): 321-324.
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The N-S equation is solved using a finite volume method with central difference scheme and a domain decomposition technique, an internal coupling condition satisfying the conservation of flux is used in the domain decomposition method. The complex flow field passing through a three-dimensional wing with flap is analyzed, the main features of the separated flow field are shown, it is discussed the formation of the flap side-edge vortex and its influence on the aerodynamics characteristics; meanwhile, the flap leading-edge bubble separated flow is also illustrated.
New Strain Energy Functions of Blood Vessel (Ⅰ)
WANG Shou-mei, LI Ning, XU Ming
2001, 27(3): 325-327.
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Investigation of the consequence of large deformation of blood vessel due to change in transmural pressure is crucial to the understanding of vein graft or other surgical operations involving blood vessel. The paper proposes and verifies new constitutive laws describing nonlinear stress-strain relation of orthogonal anisotropic materials. It can be used for large deformation calculation of blood vessels in the bio-mechanics regime. The derivation of the constitutive law is pure mathematical reasoning based on only one assumption that the stress-strain relation takes a polynomial form. Application is made in a blood vessel test. The correlation between the proposed formula and experimental data is excellent and better than that of the existing exponential expressions
New Strain Energy Functions of Blood Vessel (Ⅱ)
WANG Shou-mei, LI Ning, XU Ming
2001, 27(3): 328-331.
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The first part of this paper proposed and verified new constitutive laws describing nonlinear stress-strain relation of blood vessel. It can be used for large deformation calculation of blood vessels in the biomechanics regime. The correlation between the proposed formula and experimental data is excellent and better than that of the existing exponential expressions. But when the material is high nonlinear, the Taylor expansion may have too many terms. It's very difficult to get the material constants corresponding to those terms. So a correct term is added in this part to decrease the number of the terms.
Study of Bird Impact Loading Model
WU Cun-hao, YANG Jia-ling, ZANG Shu-guang, MA Juan-rong
2001, 27(3): 332-335.
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To study the bird impact problem, one key point is to establish the bird impact loading model. This paper, based on the full scale bird impact tests, and detailed analysis the results of high-speed photography, dynamic strain gauge, puts forward that triangle pulse simply model could be simplified by bird impact loading of inclined impact process .The analysis results that calculate the simply model using finite element analysis tools are accordance with the results from full-scale bird impact tests.
Delamination Growth of Composite Sandwich under Hygrothermal and Mechanical Loads
ZHANG Zhi-min, LI Xiang-yang
2001, 27(3): 336-339.
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The local buckling may occur in composite sandwich with delamination induced by impact damage. This often causes delamination growth and structure failure. The delamiantion growth is studied by using the variational method of moving boundary, and the formulas of energy release rate G along the delamination front are obtained. By employing Rayleigh-Ritz method, the hygrothermal effect on buckling character of composite sandwich plates containing delamination between two faceplate laminae is studied.
Numerical Simulation Method of Sheet Metal Stamping Process
CHEN Zhong-kui, SHI Fa-zhong
2001, 27(3): 340-343.
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Due to the large-deformation and large-strain, in addition to the three non-linearity (geometry, physics and contact) coupling with one another during the stamping process, the computational process is extraordinarily complicated. Based on the principle of virtual work, this paper deals with elastic-plastic FEM(Finite Element Methods) of sheet metal stamping process, and then this method is introduced into related analysis processes. At the same time, by using Updated Lagrange Method, a formulation of FEM is deduced, a FEM model of sheet metal stamping process is proposed, and a corresponding analysis program is developed. Numeric results obtained from an automotive oil pan are illustrated to show the model-s validity.
Data Reduction Based on the Equivalence Class Partition of Attribute Set
ZHANG Xue-ming, SHI Fa-zhong
2001, 27(3): 344-347.
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Duing to the high dimension and huge data of large database, data reduction plays more important roles in the knowledge discovery of database. Existing data reduction method for identify redundant and irrelevant attributes can be grouped into three type: enumeration search, heuristic search and randomized search,all have low efficient and may lost important information, and need improvement in order to satisfy the data mining requirement. Equivalence class partition based on the attribute set can identify the redundant and irrelevant attributes in essence, and can rapid and accurately compute the number of equivalence class partition, make data reduction more effective and data mining more efficient.
Calculation of an Orthographic Projection with the Projection Theorem
ZHENG Guo-lei, ZHU Xin-xiong, XU De
2001, 27(3): 348-350.
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This paper describes the process of proving the sole existence of an orthographic projection for a 3-dimentional geometry based on the projection theorem in the optimal theory, and proposes a new method of calculating the orthographically projective transformation of an object. It includes: ①An orthographic projection of a 3-dimentional geometry is defined again with the mathematical concepts; ②In order to apply the projection theorem, a series of propositions related to the orthographic projection are proved sequentially, and then the sole existence of an orthographic projection for a 3-dimentional object is strictly testified and the orthographically projective transformation of an object is found with respect to the Fourier series; ③The advantages of the method of calculating the orthographically projective transformation are concluded.
Integrated Reverse Engineering System for Complex Product
SUN Fu-hui, XI Ping, TANG Rong-xi
2001, 27(3): 351-355.
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Reverse engineering, an important constituent part of CAD/CAM technology, is a main method in manufacturing complex product or product with main model. In this paper, the idea of integration and system is applied in reverse engineering, and a new concept, integrated reverse engineering system based on precise measurement, is developed. In addition, the key techniques including measuring, 3D model reconstructing, error controlling, and surface smoothness analyzing are discussed.
Research on Type Synthesis of Micromanipulation Mechanisms for Bioengineering
YU Jing-jun, BI Shu-sheng, ZONG Guang-hua, ZHAO Wei
2001, 27(3): 356-360.
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Firstly aiming at the characteristic of micromanipulation, the guidelines for selecting and designing micromanipulation mechanisms for bioengineering are proposed. In order to solve the problem of type synthesis of 3 DOF translational parallel mechanism, all the possible types of parallel mechanisms with 3 DOF are numbered, and the principles for the mechanism synthesis are also explained by applying the screw theory. In addition, based on the consideration for the advantages and disadvantages of the mechanisms as micromanipulators, some types of the mechanisms suitable for the micromanipulation for bioengineering are chosen. At last, both the CAD model and the available prototype of this mechanism are presented.
Application of BP Multilayer Perceptron to R&D Project Termination Decisions
LIU Quan, GUAN Jian-cheng, XUE Jing-zhi
2001, 27(3): 361-364.
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The paper discusses the considerable importance to evaluate and terminate an ongoing R&D project. Furthermore, the feasibility of neural network to estimate and terminate an ongoing R&D project is explored. On the basis of the theory and methodology of neural network, this study attempts to develop a BP neural network to make termination decisions for an ongoing R&D project in an effective manner. Finally, the validity of the proposed method is verified by an empirical study. The result shows that the method is both simple and practical.
Strong Stability with Respect to Part of the Variablesin Systems with Impulse Effect
PENG Lin-ping
2001, 27(3): 365-368.
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The present paper introduces a new kind of stability——strong stability with respect to part of the variables in systems with impulse effect. The question on the stability is discussed. Effective sufficient conditions are found for strong stability with respect to partial variables of the zero solution of an impulsive differential system. The approach present is based on the specially introduced piecewise continuous Lyapunov functions and two important lemmas. Finally the obtained criteria are applied to the investigation of strong stability of the zero solutions with respect to part of the variables in impulsive differential systems.
Chromosome Feature Extraction via Topographic Analysis
WANG Zhao-zhong, ZHOU Fu-gen, JIANG Zhi-guo
2001, 27(3): 369-372.
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Chromosome classification is very significant in the domain of medical image processing, and feature extraction is the key within this process. In this paper, the topographic analysis approach to extract chromosome features in gray-level image, which is operated by scale-space filter, is described. Bands on chromosome are described as a series of peaks and saddles, and symmetric axes as ridges. Differential geometry is used for the exact definition of ridge, as well as peak and saddle. The results of feature extraction in terms of those definitions are also presented, and they seem more precise for the classification task.

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