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2001 Vol. 27, No. 6

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Vibration of Separators in High-Speed Ball Bearings
LAI Yong-jun, LU Zhen
2001, 27(6): 619-622.
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Dynamics equations are established respectively for separators and balls of a high-speed ball bearing on the base of elector-hydro-dynamic lubrication. A model is proposed to describe the response of the separator, which was proved reasonable and reached a desirable results. On the above basis, it is suggested that high-scale vibration and impact during transition may be the main factors responsible for the fatigue fracture of the separator.
Experimental System of Serial-Parallel Micromanipulator
ZHAO Wei, YU Jing-jun, BI Shu-sheng, ZONG Guang-hua
2001, 27(6): 623-627.
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An experimental micromanipulator system was established based on a novel serial-parallel micro-motion mechanism used for micromanipulation. Considering the characteristic of the mechanism, by combining the micro vision system of computer with a capacitive micrometer, a convenient and effective kinematics calibration method for plane micro motion mechanism was proposed. In addition, an alterable integral PI control method was adopted to keep precise control of the PZT. The validity of this serial-parallel micromanipulator system was verified by the experiment of drawing circles and rectangles.
Analysis on Fluid Field of High Speed Magnetic Fluid Seal
ZHAO Guo-wei, CHI Chang-qing, WANG Zhi-shan, WANG Gua
2001, 27(6): 628-631.
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The hypothesis of velocity linear distribution in wedge-shaped gap is often used to analyze the fluid field in high speed magnetic seal. But the result can not satisfy Navier-Stokes equation completely. So, two new methods are proposed to deal with the problem. One is based on the hypothesis of linear distribution of magnetic fluid velocity on the boundary, the other solves Navier-Stocks equation by extending control region in analysis. All the data is get by numerical calculation based on magnetic field method analysis. The results show that the velocity distribution derived by new methods can satisfy all the kinematics equations. The results obtained by the two new methods are very close in any case,and they are lower than the result obtained by the old method at high speed.
Experimental Investigation of Load Decay of the Seal O-Ring
WANG Guang-zhen, CHI Chang-qing, WANG Zhi-shan, ZHAO Guo-wei
2001, 27(6): 632-635.
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Experimental research on load decay of two kinds of O-ring made of different silicone rubber under different temperature has been conducted. The results show that the load decay characteristic of the O-ring is related to the material of the O-ring, and temperature can change load decay characteristic, the speed of load decay increases with the rise of O-ring temperature. By the study to the theory of load decay and analysis to the results of experiments, a theoretical model has been conducted to describe the load decay characteristic of the O-ring,it matches the results of the experiments very well.
Method of Flying Dynamic Real-Time Forecast Based on BP Neural Network
WANG Shu-ming, XIA Guo-ping
2001, 27(6): 636-639.
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The disadvantages of the traditional BP neural network include low speed of convergence, high sensitivity and indefinite layers, etc. This paper develops a new BP network model, which can improve the quality of the real time and precision, and applies the developed BP network model to the dynamic forecast of aircraft track. Owing to the advantages of BP network in the aspects of acquisition, remembrance and self-adaptation, it can make the results of the dynamic forecast more efficient and more precise.
Empirical Study on R&D Projects Termination
GUAN Jian-cheng, LIU Quan, CAO Yan-bin
2001, 27(6): 640-643.
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On the basis of the experience of relevant experts and relevant literatures, the authors propose a variable set for evaluating ongoing R&D projects. An improved Fuzzy pattern recognition method is further presented and applied successfully to terminating decision for ongoing R&D projects of some aircraft company. There are two improvements in the method. First, the weights of the variables are computed by the statistic method. Then, the distance between the samples is calculated with the generalized Euclid distance expressions. The empirical study shows the generalized Euclid distance expressions proposed here is practical and the result of its implementation is effective.
Research of Task Scheduling in NetworkParallel Computing Environment
HU Kai, ZHANG Yi, HU Jian-ping
2001, 27(6): 644-648.
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Clusters of workstations on common network are much increasing being used as cost-effective parallel computing platforms. Task scheduling is one of the crucial problems in cluster computing. A new scheduling graph model is developed to present a kind of special parallel program, which solves synchronous working problem among coarse-grained tasks in message passing system. A scheduling algorithm that maps this kind of program onto a cluster is provided, which consists of some idle workstations in a LAN for parallel computing. It is demonstrated that algorithm can reduce the completion time of the parallel program.
Analysis and Design of Aeronautical Telex Processing System
HE Guo-bin, MA Shi-long
2001, 27(6): 649-653.
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Aeronautical Telex Processing System(ATPS), which can be applied widely in civil aviation, is a software processing the aeronautical telex that acts as information media among civil aviation departments. There are many shortcomings such as poor universality, bad integrality, improper way of data publishing in currently used such systems. In view of solving these problems and utilizing the widely-adopted technologies of UML, middleware and component, a new version of ATPS, ATPS 2.0, is analyzed and designed.
Calculation and Simulation of Transient Heat Load for Cabins
FAN Wei-qiang, ZHUANG Da-min, YUAN Xiu-gan, LI De-gang
2001, 27(6): 654-657.
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On the base of design for new fighter planes, a method for calculating and simulating transient heat load for cabins has been proposed. The method gets the temperature of every wall of a cabin by calculating equations controlled by coupled heat conduction, convection and radiation.This paper analyzed the effect of the sun radiation on the panel, body, seat and the air in the cabin. Finally, the transient heat load for some fighter plane during a complete flying procedure has been calculated. The results have been compared with ones obtained by old methods.
Drag Reduction Technique of Cylinder and Mechanism Research
TAN Guang-kun, WANG Jin-jun, LI Qiu-sheng
2001, 27(6): 658-661.
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The hydrogen bubble flow visualization technique has been used to study the flow around a hollow circular cylinder with several splits and the drag reduction mechanism. The experiments cover the cylinder with different number and arrangement of splits, different angle of attack. The primary criterion of drag reduces is whether the splits change wake of the hollow cylinder. According to this criterion, the experimental result indicates when the attack of a split is in the range of |α|≤60°, the cylinder possesses drag reduction characteristics, and the optimum angle of attack is 20°. Under this condition, a two-dimensional jet flow is visible in the downstream split, which affects the wake flow pattern. However, when the attack of the split is equal to 70°≤|α|≤90°, the split can hardly affect the drag of the cylinder.
Image Acquisition Research in DPIV
WEI Run-jie, SHEN Gong-xin, DING Han-quan
2001, 27(6): 662-665.
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This paper firstly proposes the phenomena that the diameter of particle image obtained is larger than usual with the increase of aperture stop diameter in short object distance image acquisition in PIV measurement which was called spherical aberration. Then the solution was acquired directly by resolving the non-line formula of image acquisition through one positive thin-lens and the relation between the aperture stop and the spherical aberration was computed. Finally the ideal particle image could be acquired by making use of spherical aberration properly in the aim of sub-pixel calculation in PIV and the analysis was also proved by actual experimental results.
Experimental Study of Supersonic Jet Flow Using DPIV
DAI Qin, WEI Run-jie, HUANG Zhan, SHEN Gong-xin
2001, 27(6): 666-669.
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Experimental study of supersonic jet flow using digital PIV system with frame straddle CCD camera is introduced in the paper. The diameter and Mach number of the Laval nozzle exit are 13.8mm and 1.5 respectively, the vector field and wave patterns of the jet flow in different pressure ratio of the stagnation pressure with the surrounding static pressure were observed. The results show the different of flow speed and other parameter of flow field before and after the shock wave. The generation of particles and seeding method are also simply described in the paper.
Experimental Investigations of Atomic Oxygen, Temperature, Ultraviolet Radiation Effects on a Spacecraft Material-Kapton
ZHAO Xiao-hu, SHEN Zhi-gang, WANG Zhong-tao, XING Yu
2001, 27(6): 670-673.
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Experimental investigations of atomic oxygen, temperature rise, ultraviolet radiation effects on Kapton, a spacecraft material in common use, were conducted using atomic oxygen effects ground-based simulation facility. The samples aspect, mass and surface morphology before and after experiment was compared in this thesis. Reaction characteristics of Kapton in the facility and influence rule of temperature change as well as ultraviolet radiation on atomic oxygen effects of Kapton were acquired. Optical properties, such as reflectivity and transmissivity, before and after experiments were measured and compared.
Topological Structure Evolution and Stability of the Cross Flow Pattern Around a Slender
LI Guo-hui, DENG Xue-ying
2001, 27(6): 674-676.
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Topological structure and stability of a slender cross flow at different angles of attack was discussed by the stability theory of dynamic system. It was proved that the development of slender vortices leads to the change of topological structure about cross flow. And it is the change from stable and symmetrical vortices flow pattern to instable and symmetrical vortices flow pattern, and then to stable and asymmetrical vortices flow pattern due to little disturb which leads to the development of asymmetrical slender vortices.
Influence of the Twin Vertical Tails on the Aerodynamic Characteristics
Lü Zhi-yong, LI Jian-qiang, QIN Yan-hua, HANG Hua
2001, 27(6): 677-680.
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In the study of the advanced aerodynamic fighter configuration,the location of twin vertical tails is always an important problem. In this paper, a fighter model of canard configuration was studied. The study includes three parts: measurement of aerodynamic force, flow visualization and PIV experiment. It is found that when the twin vertical tails are located on the back-inner of fighter's body, the maximum lift coefficient is max. The process of vortex breakdown and flow character are very similar with the state of no vertical tails. This indicates that the main effect of twin vertical tails on wing vortexes promote the vortex breakdown, so the aerodynamic characteristics of fighter will be deteriorated.
Influence of Sintering Temperature on Fracture Toughness for High Toughness Alumina Ceramics
LIU Tong, LIU Wen-ting
2001, 27(6): 681-683.
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The fracture toughness of hot-pressed alumina ceramics at different sintering temperatures was examined. The high fracture toughness alumina samples were made from low-temperature-calcined α-alumina powder prepared from aluminum hydroxide by seeding of wet grinding abrasion powder. As the sintering temperature increased, the fracture toughness increased to an optimal temperature and then decreased. The fracture toughness is increased by the formation of elongated grain structure and decreased by abnormal grain growth.
P-S-N Curve of Fatigue at Low Temperatures of Welded Components
JIA Xing-lan, LIU Wen-ting
2001, 27(6): 684-686.
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The P-S-N curve of fatigue at low temperatures is the design basis against fatigue of welded components in winter. The fatigue life of welded components at -25℃ temperature was measured on PLG-300 kN high-frequency fatigue testing machine at four stress levels, and the S-N curve of welded components was derived. The P-S-N curve of fatigue at low temperatures was theoretically obtained by using the method of single side tolerance analysis of small-number specimen experiments and the experiential CV value of logarithmic fatigue life (lgN ) of welded components. This method is a simple and economic one, but its perfection needs more experimental data.
Effect of Tabs on the Thrust of a Convergent Nozzle
HUANG Yong, GUO Zhi-hui, WEI Fu-qing, WU Shou-sheng
2001, 27(6): 687-689.
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An experimental investigation on the effect of tabs, which is fixed on the exit of a convergent nozzle, to thrust characteristics has been conducted at both subcritical and supercritical flow conditions. The variable parameters of tabs are block ratio, inclined angle and the number of tabs. The experimental results show that the tabs indeed cause thrust loss, and the thrust loss will increase with the block ratio of tabs. Within the test range of the experiments, the thrust loss is between 0.65%~1.35% per 1% tab block ratio, and especially about 0.8% per 1% at supercritical flow condition.
Prediction of the Response of SMA Superelastic Systems Under Stationary Random Excitation
YAN Xiao-jun
2001, 27(6): 690-693.
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With an advantage that the motion equation of the system can be linearized directly in closed form, a simple superelastic model for SMA (Shape Memory Alloy) was proposed in the equivalent linearization method. The method was employed to predict response of SMA superelastic system under stationary white noise excitation. The results are in good agreement with those obtained by numerical simulation in all excitation levels for systems with different damping capacities. It was finally concluded that the equivalent linearization method based on the model can be used in engineering with higher computation efficiency.
Optimal Design for Sculling algorithms of SINS
GENG Yan-rui, WANG Yang-zhu, CUI Zhong-xing
2001, 27(6): 694-697.
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High speed and accuracy sculling compensation algorithm plays a key role in strapdown inertial navigation system(SINS). A fresher research on sculling compensation algorithms and their error characteristics is made. The equations of sculling coefficients and of the errors are derived first, then 17 sorts of sculling compensation algorithms are proposed. Finally the computer simulation is taken to show the character of sculling compensation errors.
Parity Vector Compensation for Multi-Sensor Fault Detection
WEI Chun-ling, ZHANG Hong-yue
2001, 27(6): 698-701.
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A scheme based on neural network is presented to improve the fault detection and isolation (FDI) performance of a redundant strapdown inertial measurement unit. The neural network is trained to eliminate the effects of input axis misalignment, scale factor error and biases on parity vector. One advantage of the proposed technique over other compensation algorithm is that it does not require dynamic equation of error states and statistics of noise. When the neural network is trained on line with delayed samples, the compensated decision function is sensitive to slow-varying type fault. The simulation results show that the technique could significantly improve the FDI performance of the skewed inertial sensor sets.
Application of Local Observability Theory in the In-Flight Alignment of INS/GPS
LIU Zhun, CHEN Zhe
2001, 27(6): 702-705.
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Based on the study on the observability, the local observability theory has been used in INS/GPS integrated system, the condition number of local observability matrix in various maneuver modes have been computed, and the optimal maneuver mode has been found. It has been shown by the research results that, by means of implementing sine level maneuver flight, the local observability of the attitude errors can be increased, the flight alignment time can be reduced obviously, and the attitude errors can be cut down greatly. When the alignment time is about 120s,the mean values of attitude errors in the directions of east, north and up are 12.34″,12.19″,-28.31″,　and their standard deviations are 0.97″,1.05″,0.62″.
Fault Diagnosis Expert System for Aircraft Electric Power System
ZHU Xin-yu, SHEN Song-hua
2001, 27(6): 706-708.
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Based on artificial intelligence theory, the authors developed aircraft electric power system monitoring unit. By using expert system theory, some aircraft electric power system across-the-aboard has been analyzed. The state monitoring and fault diagnosis can be carried out and the information of abnormality or fault can be given. By using the expert system with actual applying value, the experience to diagnose fault has been presented for all non-alionics system.
Study on Three Dimensional Scattering Distribution of Complicated Targets
LIU Jiu-wen, LI Jian-hui, HAN Xue-wen, LI Qing
2001, 27(6): 709-712.
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By setting up the numerical model of a complicated target, applying outside normal vectors of visible patches of each individual body, and useing Z-buffer algorithm to solve shielding between multi-bodies of complicated targets, the three dimensional scattering problems are analyzed successfully. The currents on the surface of the targets are calculated by solving EM boundary problems. The results obtained by the algorithm are verified by tested results. The method is proved to more accrete, practical, and reliable. The three dimensional scattering distribution could be given in visible way.
Influence of Nonstationarity on SAR Imagery Models and De-Speckling Filters
MA Zuo-min, MAO Shi-yi, LIU Xiang-lin
2001, 27(6): 713-716.
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From the stochastic process point of view, Synthetic Aperture Radar (SAR) images are divided into four cases as stationary within resolution cell, nonstationary within resolution cell, stationary within local processing window and nonstationary within local processing window according to their stationarities. Then the influence of nonstationarity on multiplicative noise model of speckle, scene-speckle product model and structured neighborhood model are investigated, stationarity satisfactory conditions of these models are derived respectively. The performances of various kinds of de-speckling filters are re-assessed based on the above analyses, and filtering results of real imagery are given.
Research and Development on the Stamping Die CAD System of Aircraft Sheet Metal Parts
YUAN Hui, WAN Min, LI Xin-jun, ZHENG Shuang-lin
2001, 27(6): 717-720.
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Using AutoCAD2000 as developmental platform and Sybase as DBMS, the stamping die CAD system of aircraft sheet metal parts is studied based on the developmental software (Visual Lisp and VBA of AutoCAD) and Ashbase (Aircraft sheet metal forming database). The parameter drawing for the standard parts and the common parts is realized, and the module of deep drawing die designing is developed. This system can produce 2D and 3D assembling drawing of stamping die, so it improve the efficiency of die design and has good practicability.
Development of Novel Composite Baton
SUI Gang, ZHANG Zuo-guang, ZHONG Wei-hong, SUN Yan
2001, 27(6): 721-724.
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The baton is one of routine equipment for armed policeman ensuring public security. The inside of traditional baton is made of metal component. So the whole baton is heavy and cause hand vibrated, and even have a danger to hurt opponent. The novel composite baton was researched detailedly in this paper. Firstly, different configuration and manufacturing technology of composite as the component inside baton were investigated, and the form of cylindroid spiral spring was confirmed. The elasticity force, bend reversion rate and damping property of composite baton were also tested and analysed. Compared with traditional metal baton, composite baton not only conforms to international convention, but also has good performance.
Quantitative Analysis of Surfactant in the Degreasing Solution
QIAN Jian-gang, LI Di, GUO Bao-lan
2001, 27(6): 725-728.
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Aliphatic alcohol polyoxyethylene ether(OS-15,a nonionic surfactant) and sodium dodecyl benzene sulfonate(SDBS,an anionic surfactant) in the degreasing solution were analyzed quantitatively by the method of sodium tetraphenylborate recoil titration and ultraviolet spectroscopy respectively.It is showed that sodium phosphate, sodium silicate and SDBS in the degreasing solution have no effect on the analytical result of OS-15. Sodium phosphate, sodium silicate and OS-15 have little effect on the analytical result of SDBS.Sodium stearate and sodium palmitate produced by the reaction of saponifiable oil and alkali of degreasing solution were removed by filtration. Non-saponifiable oil were removed by centrifugalization.
Localized Nuclear Reactions and Dynamic Casimir Effectin Electrochemical Process
JIANG Xing-liu, WEN Xiong-wei, ZHANG Jian-gang, HAN Li-jun
2001, 27(6): 729-732.
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Localized nuclear activations in electrochemical process have been observed by CR-39 solid detectors, autoradiography and energy dispersion X-ray analysis of Pd cathode electrolyzised in light and heavy water. Nuclear reactions and excess heat in electrolysis process were interpreted by two mechanisms: one is the torsion coherence of vortex dynamics with the zero-point-energy induced by localized intense field emission of micro-protrusion of the cathode; and another is dynamic Casimir effect of transient evolution of gas bubbles. A variety of anomalous phenomena in nature or at laboratories could be explained by the model of quasar vortex structure with extremely high energy cosmic rays.

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