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2000 Vol. 26, No. 1

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Study on Shape-Memorizing Function of Ethyl-Vinyl Acetate Copolymer
WANG Shi-ren, GUO Mei-li, XU Xiu-cheng, HE Peng
2000, 26(1): 1-4.
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The characters of shape-memorizing polymer were analyzed and some evaluations standard on it were proposed,such as shape recovered rate,shape fixed rate and shape recovered speed,etc. The shape memorizing function of the EVA plastic had been studied,the results indicated that the EVA plastics can be cross-linked with DCP ,and the properly cross-linked EVA will have a good shape memory properties, which shape-recovering rate and shape fixed rate can be 95% or more. The structure of EVA was also analyzed and the relationship between shape-memorizing properties and structure has been discussed. The result through DMTA analysis also indicates that the increasing content of DCP will decrease the molecular weight between the cross-linkage point(c) of EVA. In additional, the study indicates that the shape fixed rate was linear to the ratio of melted modulus to room temperature modulus.
FiniteElement Analysis of Temperature Field of PCB and Components
LI Xiao-ming, Lü Shan-wei, GAO Ze-xi
2000, 26(1): 5-7.
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Heat transfer was introduced. The finite-element method (FEM) is used to investigate steady-state two and three-dimensional heat transfer in dual-in-line component and PCB. Two methods are compared through real examples' temperature distribution. And experiments with point test method are done to compare with the results of calculated and results are much in accord with each other. Conclusion is also given that three-dimensional finite-element method is more complex and with it more particular messages could be obtained.
A Kind of Dipole Antenna with Broadband Characteristics
Lü Shan-wei, YANG Xue-bin, JIA Xiao-xiao, ZHOU Jian-jun
2000, 26(1): 8-11.
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The broadband dipole antenna presented is a rotationally symmetric structure consisting of conductor wire whose surface shape is smoothly joined by biconic section, spherical stage and cylinder dipole each other in series in the direction of antenna axis, fed by a coaxial cable with impedance of 50 Ω at center. Assuming that the equivalent current on the surface is variable along the only tangential direction of the envelope in the conductor axis, thecurrent distributions are calculated by means of the moment method. The triangular functions are chosen as the expansion functions and weight functions. An example of the broadband dipole antenna is shown and radiation patterns, gain, input impedance are computed. Also VSWR is computed and measured. It is found that the antennas studied have satisfying broadband characteristics.
Prediction Method of Visibility of GLONASS Satellites
LIU Hui, WANG Yin-feng, ZHANG Qi-shan
2000, 26(1): 12-14.
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A visibility prediction method of GLONASS satellites is presented based on the developing experience of GLONASS receiver. Given a certain known status, the spatial rectangular coordinates of the predicted satellite are calculated according to the satellite's operating law. Then the coordinates are converted to topocentric coordinates referenced to the ground observing point. The elevation angle of the satellite is computed and the visibility is obtained. The whole deducing process is discussed in detail . The orbits prediction incorporates impacts of several imperfect forces.True GLONASS almanac are used to calculate the visibility and to verify the results. This method is easily to be applied and deserves high accuracy. It is valuable in GLONASS receiver research.
Improved Method for Designing Wideband Microstrip Antennas
LIU Zhang-fa, Lü Shan-wei, LI Shi-zhi
2000, 26(1): 15-18.
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The narrow bandwidth property of a microstrip antennas is one of the main reasons that restrict its wide usage, the way to broaden the bandwidth of microstrip antennas has been concerned by investigators. A simple and practical method for the design of broadband microstrip antennas is proposed in this paper. To confirm the applicability of the method for the designs of the proposed antennas at L-band, experiments have been carried out. The measured results show the proposed antennas have a bandwidth of 25.7%, its gain in operating band is larger than 8dB. Also, the method proposed in this paper is applicable to the design of other mutilayered microstrip patch antennas.
High Frequency Resolution Acousto-Optic Channelized Receiver
CHENG Nai-ping, JIANG Xiu-fu, SHAO Ding-rong
2000, 26(1): 19-21.
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Through the basic principle analyses of acousto-optic channelized receiver, how to improve the SNR by increasing integrating time is discussed. The mathematical model of acousto-optic channelized receiver is establish to get further analyses. Based on this model, a few important parameter of the receiver are discussed, which are channelized choice,out band control, dynamic and SNR. The design of the acousto-optic channelized receiver is realized. At the end, the two important parameters and the optic system of the acousto-optic channelized receiver which is designed by ourself in our laboratory are presented. The two important parameters are: the frequency of the acousto-optic channelized receiver=50kHz,the channelized number of the acousto-optic channelized receiver=1000.
Evolution of Intelligent Transport System(ITS) and its Model Research
YANG Dong-kai, WU Jin-pei, ZHANG Qi-shan
2000, 26(1): 22-25.
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Intelligent Transport System (ITS), also called Road Transport Telematics (RTT) in Europe, is a new transport system based on high-tech including system engineering, electronics, telecommunication and informatics, and which penetrated into airborne, railage and marine. ITS can amplifier the capability of traffic and service level, improve environment and energy efficiency. After introducing the common meanings of ITS and its evolution at home and abroad, discipline system model, service function model and network layer model about ITS are proposed, and the benefits of these models are described. Finally, the standardization issues of ITS and the influence of model research are simply introduced.
Robust Fault Diagnosis of Integrated Navigation System
JIN Hong, ZHANG Hong-yue
2000, 26(1): 26-29.
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The problem of fault detection of a navigation system is discussed and an approach to detect faults of an integrated navigation system is proposed by designing the optimal robust vector sensitive to special navigation system fault in this paper. Only the measurement data of sensors are used, and the real dynamic model needn't be considered. The proposed approach is compared to the usual parity detection method. Finally, an example of an integrated navigation system composed of three uncorrelated navigation systems is given and simulation results show the robust approach has obviously improved the ability of detecting and isolating fault.
Induced-Oscillation of Man-Vehicle Closed System of FBW Aircraft
FENG Ya-chang, LI Lu-yu
2000, 26(1): 30-33.
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Severe Pilot-Induced-Oscillation(PIO), which is potentially dangerous, paroxysmal and may lead to losing control of flight, is the principal cause of the frequent accidents in the development of FBW aircraft. This compels us to study its flying dynamic mechanism, find out the corresponding design defects of flight control system, figure out the design methods, tools and work procedures to prevent it. The accidents caused by the PIO of FBW aircraft have actually promoted a new round of consideration to the issue of man-vehicle coupling. This includes advancing more precise definitions and more all-sided method of classification, seeking more effective evaluation criterion which considers the nonlinear factors and can identify the tendency of severe PIO.
New Control Method of Adaptive Fuzzy-Neural Networks for Brushless D\^C\^ Motor
FAN Zheng-qiao, MA Shu-tong
2000, 26(1): 34-37.
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This control method was based on combining fuzzy control with adaptive and bang-bang control. Fuzzy controller and mechanism are realized by neural networks. In double closed loop system the current regulator consists of proportional and integral controller, the speed regulator consists of bang-bang controller and fuzzy controller combining with adaptive mechanism. Fuzzy controller is realized by three layers of neural networks, which learns off the line. Improved BP algorism is used to learn. Adaptive mechanism is realized by an artificial neuron, which dynamically learns on the line during the operation of the system. The superintendence Hebb algorism is used to learn. Operation stage of the motor resolves which controller to work. It-s shown by the results of digital simulation that the system has good dynamic and static performance, it also has excellent adaptive performance.
Synthetic Stress Life Testing for Hydraulic Pump
WANG Shao-ping, LI Pei-qiong
2000, 26(1): 38-40.
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In accordance with the features of hydraulic pump, this paper analyzes the failure mode and selects the sensitive stress. According to failure effects that sensitive stresses impose to hydraulic pump and researches that the U.S.A life test standardization develop, we can drive at the conclusion that the synthetic stresses reliability test can verify the reliability and the life of hydraulic pump. Because hydraulic pump has many characteristics such as high price, long life and small test samples, this paper also analyzes the statistical method for synthetic stresses life test under variable load spectrum. The life test experiments indicate that the method of synthetic stresses life test are satisfied to analyze the life of mechanical-electrical products.
Some Questions on Kalman Standard Decomposition of Linear Time-Invariable System
ZENG Jian-ping, CHENG Peng
2000, 26(1): 41-44.
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It is shown that for a linear time-invariable system,its Kalman canonical form can not be obtained by decomposing the system into its controllable canonical form,and then decomposing its controllable and uncontrollable subsystems into their observable canonical form,respectively.The possibility is discussed to construct a non-singular transformation which transforms the system to its Kalman canonical form through choosing a basis in < A|β >∩η,< A|β >∩η⊥,< A|β >⊥∩η and < A|β >⊥∩η⊥ .Finally ,it is proved that the system can be transformed to its Kalman canonical form using an orthogonal transformation under appropriate conditions.
Design of Life Usage Monitoring System of Aeroengine Critical Part
HONG Jie, ZHANG Da-jun, HAN Ji-bin
2000, 26(1): 45-48.
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It takes very important role that aeroengine load and life monitoring technology in monitoring and assessing operating condition, life consumptiom and remaining life of aeroengine. It can improve the safety and reliability, and reduce direct usage cost of engine. In this paper, the life usage monitoring system is including data condensing processing,LCF counting for every flight and Low Cycle Fatigue, Thermal Fatigue, Creep, and any combination of them can be dealt with. The information obtained by life monitoring system is very useful for the database of part management which will be used to track the life usage of the engine parts.
Comprehensive Analyses of Energy Spectrum and Reflection Coefficient in front of Vertical Breakwaters
XUE Xiao-chun, ZHAO Zi-dan
2000, 26(1): 49-51.
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The distribution rule was investigated of energy spectrum and reflection coefficient by the method of wave spectrum. For some reason,the results by experimental and mathematical method were out of regular allowance without considering influence factor of the reflection coefficient. Because energy spectrum in front of breakwaters and incident waves spectrum were detectable,the reflection coefficient can be derived from the formula of energy spectrum in front of vertical breakwaters; therefore, all reflection coefficient data along the range can be obtained.
Study on Ventilating Design Method in High Speed Train
ZHUANG Da-min, LIN Guo-hua, YUAN Xiu-gan, WANG Xiao-xin
2000, 26(1): 52-55.
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For the characteristic of high closing in compartment of high speed train, the ventilating design should ensure passengers' safety and comfort. Since the traditional method of temperature and velocity distribution depending on free jet experimental equations cannot consider the effects of push pull flow and obstacle, the ventilating design mainly depends on modeling experiment. By regarding the push-pull flow and the shape of compartment and the seats as a integer, the research method in this paper directly simulate temperature and velocity distribution to ensure the demanding of comfortable air conditioner and conveniently obtain feeding velocity and feeding temperature difference. This method is not only applied in ventilating design of high speed train but also applied in ventilating design of general manned train and of aircraft's cabin.
Human Thermal Comfort Calculation of Air-Conditioned Cockpit
WU Yu-ting, LIN Guo-hua, YUAN Xiu-gan
2000, 26(1): 56-59.
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Thermal comfort is a important standard for assessing a cockpit air-conditioning system. A thermal comfort calculation model of air-conditioned cockpit is founded on the base of human thermal balance equation and thermal comfort hypothesis proposed by P. O. Fanger. Furthermore, the assessment method of thermal comfort is presented. As a result,the above-mentioned works lay a theory foundation for the thermal comfort quantitative assessment of air-conditioned cockpit. The thermal comfort of three kinds of air-condition scheme of the cockpit were calculated by using the thermal comfort calculation model and the thermal environment. quality of three kinds of schemes was assessed. The result indicated that the third scheme is the best one in terms of thermal comfort.
Engineering Calculation Research of Aerodynamics　for Aircraft with Double-Delta Wing Configuration
HUANG Jun, WU Wen-zheng, WU Zhe, KE Xian-de
2000, 26(1): 60-63.
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The lift and drag characteristics of double-delta wing configuration is more ascendant than that of delta wing configuration. To seek for the optimized aircraft design scheme with numerical methods is firmly bottomed upon the engineering calculation of aircraft aerodynamics. By using the semi-experiential engineering arithmetic based on the ideology of area ratio, the slope of lift coefficient curve, the zero-lift drag coefficient and the induced drag factor of double-delta wing aircraft were calculated. Being compared and corrected by the data from wind tunnel tests, it is shown that the precision of calculated results quite meets the requirements of conceptual aircraft design. The arithmetic has been successfully adopted in the conceptual design of an aircraft version.
Fuzzy Optimization of Geometrical Parameters of Fighter Basing on Fluctuating Weights
LI Jing, LI Tian, WU Zhe
2000, 26(1): 64-66.
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Basing on the theory and formula of fluctuating weights given by Prof. Wang Peizhuang, the character of the fluctuating weights and the comprehensive evaluation function of the fluctuating weights and the difference between the fluctuating weights and constant weights are discussed .And then the fluctuating weights are used in the integrated aerodynamic-stealth design of geometrical parameters of fighter. The results of the optimizations using fluctuating weights and constant weights respectively are discussed. The results show that the optimizations method using fluctuating weights is better than that using constant weights.
Use of Fuzzy Optimization in Conceptual Design of Fighter
LI Jing, LI Tian, WU Zhe
2000, 26(1): 67-69.
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Linear function is used to form the satisfactory functions of the objectives and constraints of the integrated aerodynamic-stealth design of fighter geometrical parameters, such as the root chord and tip chord of the wing, half span of basic wing, the leading-edge sweepback of the wing, the sideway elongation coefficient and the radius of the fuselage at the interface position with the wing, and then,basing on these functions, the multiobjective fuzzy optimization model was established. Punishment function is used to transfer the constrained optimization to unconstrained optimization and the Nelder and Mead Method is used to solve this optimization problem.
Calculation of Transient Heating Load for Avionics Pod
YU Jian-zu, CHEN Yan-min, SU Nan
2000, 26(1): 70-74.
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The calculation of transient heating load is fundamental to the design of the environmental control system (ECS) for avionics pods. In this paper the dynamic heat-balance equation for the avionics pod and the heat transfer equation for the pod wall have been established. The transient heating load of the pod have been computed by means of finite difference equations. The influences of the flight condition and the thermal inertia of the pod on the transient temperature in the pod have been analysed. Finally the paper has adopted the design concept of cool storage for saving energy and rationally defined the design heating load of the ECS for the avionics pod.
Characteristic Analysis of Composite Thin\|Walled\= Beams under Constrained Torsion
DENG Zhong-ming, ZHU De-chao
2000, 26(1): 75-78.
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Based on Vlasov theory, a layered warping model was presented for mechanical analysis of composite thin-walled beams with arbitrary closed-section. Besides the effects of shearing strain and torsion warping, the influences of materialsand the ply arrangement on the warping displacement and stress are also discussed. The numerical results show that the warping displacement and stress of the composite thin-walled beam are differ from layer to layer due to influence of materials and the ply arrangement.
Image Processing Method of PIV Technique
DUAN Li, KANG Qi, SHEN Gong
2000, 26(1): 79-82.
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The image processing method of PIV was studied on the base of the image correlation theory in this paper. The simulated particle image displacement field was reconstructed. The reconstruction result of auto correlation and cross correlation , and the error of cross correlation were given. The difference of this two correlation method was analyzed. The cross correlation is a good method that can increase the PIV's accuracy, so the frame straddling technique is favorite to be developed for PIV measurement.
HPIV and its Application
DUAN Li, KANG Qi, DING Han-quan, SHEN Gong
2000, 26(1): 83-86.
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HPIV technology can realize the measurement of three-dimensional velocity (u,v,w) in a three-dimensional space. Using two Nd: YAG pulsed lasers , two exposures, two symmetry reference lights, and off-line holographic technique, three-dimensional particle flow field was recorded. Using SPIV technique's photographic method, two directions' particle images were obtained for three-dimensional calculation. Using cross correlation, the velocity direction was resolved.Using this HPIV system, the three-dimensional vortex flow passed diagonally through a cubic box was measured. The measurement of three component-velocity in three-dimensional flow field was realized.
Active Vibration Control of Smart Plate with SelfSensing Piezoelectric Actuators
FANG You-liang, WU Zhe
2000, 26(1): 87-90.
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For the four laterals simply supported plate, the transverse deflection of plate is expanded over the modal shapes, the electroelastic model with self-sensing actuators plate is given, and the current is considered as output variable of measurement equation. Generalized modal coordinates being state variables, LQG and H∞control is proceeded using the state space equation. In this paper, a self-sensing thin plate with three pairs piezoelectric films is bonded on the surface of base structure, the H∞ control solution is compared with that of LQG control. Singular value curve of system is given, velocity and displacement responses of one location in the plate are drawn, and applied voltages for actuators are given. The simulation solution illustrates the effectiveness of the control method in this paper.
Interactive Method and Experiment in 3D Human Motion Data Abstraction
JI Bai-hua, YUAN Xiu-gan, WEN Wen-biao
2000, 26(1): 91-94.
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Interactive method is raised in this paper to abstract three dimension human motion data from video by combining human distinguishing and computer graphics simulation. The approach to abstract human three dimension data is a whole posture, not a single joint, and which is different from the manual approach. A series of experiments are taken to test human distinguishing which is the key in the interactive method. Graphic, photo and video are used as samples in the experiment. The result shows that human distinguish posture well. In the bottom of this paper, the procedure of data processing is introduced that how to compute velocity and acceleration of each joint angle and each limbs.
Construction of Scene Database in Distributed Simulation
HE Hong-mei, ZHAO Qin-ping
2000, 26(1): 95-98.
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The construction process of scene database is introduced in detail. Some key technologies which are used during the construction process are discussed, such as the advantages and disadvantages of equal sampling interval terrain model and triangulated irregular network terrain model, three integration methods of culture feature and terrain, and the level of detail representation of terrain. Then the scene paging algorithm and the relationship of paging and construction are provided. Furthermore, one example which is implemented in DVENET is given. Finally, problems which are found during the development of DVENET scene database and its future solutions are discussed.
Grinding Parameter Optimization of Conical Drill Point Grinding Method
JIANG Hong-dao, Lü Yan-ming, CHEN Wu-yi, CHEN Ding-chang
2000, 26(1): 99-102.
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The conical grinding method has four grinding parameters, and for three drill point geometric parameters, the lip clearance angle, chisel edge angle and point angle, the flank configuration is not unique. So one more drill point geometric parameter is needed, such as heel clearance angle, chisel edge clearance angle. Using the supplementary parameter, the four geometric parameters can determine the four grinding parameters. To consider the effect of all the possible supplementary parameters together, the optimization method can be used to obtain a optimal solution,and the supplementary parameters and the grinding parameters are used as constrain conditions.
Automatic Generating 2D Drawing Based on 3D Feature Design Model
MEI Zhong-yi, ZENG Ling-wei, WU Bin
2000, 26(1): 103-106.
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The basic principle and implementing method was mainly discussed of automatically generating 2D drawing based on parametrical feature modelling system (LONICERA system ). The emphasis is introducing the theorem of creating projection view and cross-sectional view. Different to traditional 2D drafting system, this method can automatically generate 2D drawing from 3D model. The generated 2D drawing is correlated with the 3D model. When modifying the 3D model, the 2D drawing will also be changed. And vice versa.
Research and Implementation of SDAI-Based Engineering Data Management System
ZHAO You-zhen, ZHANG Tong, LIU Yi-e, DENG Jia
2000, 26(1): 107-110.
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Beginning with the most fundamental persistence function, solutions were presented which involve expanding EXPRESS model using Object-oriented Modeling Technology; extending SDAI contents properly; achieving objects' self-supplied -O function; and implementing the object-oriented encapsulation and dynamic binding, on several key technologies such as the SDA C+ + management classes, the early/late binding data access methods and the combined early/late binding operations. Using these solutions, one prototype system is developed. The motive to carry out this system is to meet the need of the integration of CAx application systems based on STEP.
Alternative Evaluation Criterion of Constructing Decision Tree of Discrimination
WANG Hui-wen
2000, 26(1): 111-113.
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An alternative criterion of evaluating the built decision tree for discrimination is discussed in this paper. The maximal decrease in undistinguished degree is proposed as the principle to choice explanatory variable for building a binary tree. From the basic concept, this new criterion is approximately consistent with the classical method using decrease in impurity. Though these two criteria are equivalent if choosing appropriate weights for the classical algorithm of decrease in impurity. The research shows that the computation of new criterion is more simple. Moreover, the result from the case study shows that the new criterion is more interpretable.
Numerical Approach to Robust Stability Test of Mixed Uncertain Systems
ZHANG Yuan, JIA Ying-min
2000, 26(1): 114-117.
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The robust stability analysis of mixed uncertain systems　can be completed by testing the H∞ norm of edges of an uncertain　rational function. To reduce the computational complexity, a numerical　approach is proposed for a class of mixed uncertain systems whose　coefficients affinely dependent on system parameters. It is shown　that the image of an edge rational function at a fixed frequency is an arc in s-plane. Further, a new formula to compute the maximal norm of the　arc is developed. Based on these results an edge test algorithm in a finite　frequency range is induced by which the computational burden can be greatly　reduced.
Software Model for Computer-Aided FMECA
ZHAO Ting-di, SUN Lin-ling, TU Qing-ci
2000, 26(1): 118-121.
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According to the theory of CAD framework and software architecture, the computer aided FMECA software model was analysis and established. Firstly, the target of FMEA software and design strategy was discussed. And then data model of the product, failure mode, and result of FMECA was established using the OTO-D(Object Type Oriented Data model) semantic model. The software structure applying the technology of CFI(CAD Framework Initiative) and running environment were described in detail. Finally, the FMECA implement methods including the visualization of product hierarchy description and the FMECA result data query, the representation of data using relation model in database, the automation of the FMECA table filling and Cr calculating were discussed in detail.
Right Essential Orders of Nonlinear Systems and its Application
WANG Lian-gui
2000, 26(1): 122-124.
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A new set of invariants was defined for right-invertible nonlinear control systems,the right essential orders. We prove that this set of natural numbers is invariant under regular static state feedbacks. On the other hand, it is pointed by an example that the right essential orders are changeable by regular dynamic state feedbacks. Some application of the right essential orders to the decoupling problem is addressed. Especially, a new necessary and sufficient condition is obtained via the right essential orders for the regular feedback decoupling problem of nonlinear systems. The relation between the right essential orders and the nonlinear Morgan's problem is also discussed. It is expected that the invariants introduced here plays an important role in the study of nonlinear Morgan' s problem.

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