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2003 Vol. 29, No. 5

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Simulation and Verification of the Temperature Field in Laser Bending Sheet Metal
Wang Xiufeng, Lü Xiaodong, Hu Shiguang, Chen Guangnan
2003, 29(5): 377-381.
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Temperature field in the laser bending process was numerically simulated by MSC. Marc software. Variations of temperature with time to cause sheet metal bending were calculated. Simulation result was verified by the temperature on the lower surface of the sheet metal, which was measured by the thermocouple temperature t ransducer measuring under the laser scanning line. Experimental curves of temper ature versus time are in agreement with simulation results. The simulation resul ts can be regarded as a basis for choosing laser technological parameters.
Study on the Reconfiguration of Blood Vessel Wall
Wang Shoumei, Xu Ming, Li Ning
2003, 29(5): 382-384.
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By-pass operation leads to reconfiguration of blood vessel wall. Growth deforma t ion gradient through stress potential in the restructuring of blood vessel was p roposed and a numerical example was given. The results indicate that at the begi nning of reconfiguration, stress in the blood vessel wall changes sharply, the c ircumferential length and the thickness grow rapidly, the changes of stress dist ribution and geometry size are gradually reduced, and the increment of thickness is gradually slowed down. This proves that stress leads to the reconfiguration of the blood vessel.
Quasi Asynchronous Parallel Process Migration Algorithm Based on Message Forwarding
Zhang Yi, Hu Jianping
2003, 29(5): 385-388.
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A new quasi-asynchronous parallel process migration algorithm based on message forwarding was presented to solve the problem of process migration in parallel c luster system. The algorithm used message driving out mechanism, message forward i n g mechanism, priority matching buffer mechanism, etc., to avoid the disadvantage s of central management and too much coordination of non-migrated process. The a lgorithm description and experiments show that it has the advantages of high eff iciency, easy management and control, and good robustness.
ChecklistBased Process Tailoring Method
Cao Huiming, Jin Maozhong, Liu Chao
2003, 29(5): 389-393.
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It is a key and complex technique that tailors the organization's standard softw are p rocess to get the defined software process fitting the specific characteristics of the project. The organization's standard software process was discussed. The pr ocess tailoring was discussed. Four aspects impacting on process tailoring were analyzed. A checklist-based process tailoring method(CPTM)was presented. The p rocedures of process tailing using CPTM were described. An application case of t he CPTM was introduced. It proves that the process tailoring can be conducted sm oothly with CPTM and the investment for software organizations can be reduced gr eatly in process tailoring.
RealTime SSR Signal Processing System Based on MultiDSP
Niu Lipi, Mao Shiyi, Li Shaohong
2003, 29(5): 394-397.
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A real-time secondary surveillance radar (SSR) signal processing system was des i gned by using four digital signal processing (DSP) and two field programmable ga te array(FPGA)．The system consists of two real-time signal-processing boards of DSP+FPGA mechanism．It implements processing of signals from SSR responder, suc h as anti- garble, defruiting ,calculation of azimuth and range,decoding of h eight and special -code of planes. The system can produce inquiring -code for air traffic control(ATC) and report statistical information timely.
Aircraft Engine Fault Diagnosis Research Using Model Identification Based Method
Zhu Zhili, Meng Fantao
2003, 29(5): 398-401.
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The capability of model identification which bases engine performance diagnostics applied to a twin-spool and separated flow turbofan engine, was evaluated using limi ted monitoring parameters. The model identification was based on non-linear eng i ne performance simulation code, so the non-linearity of the performance was con s idered by using of the balance technology between components of engine in the in vestigation. The influence of the amount of engine operating points to the diagn osis result was discussed. The investigation shows that the method can isolate differ ent faults quantitatively with high accuracy, and the method of operating points choice is concluded.
Design of Fuzzy Logical Gain Scheduling Controller for Flight Control Based on LMI
Zhang Peng, Wei Chen, Zhou Rui, Chen Zongji
2003, 29(5): 402-405.
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Linear matrix inequality(LMI), H-infinity　 control and fuzzy logic control techniq ues were used for constructing such controller. With these techniques, the synth esis problem was reduced to a convex optimization related to LMI. A detailed pro cedure for developing a fuzzy logic gain scheduler over the full flight envelope was given in order to overcome the drawbacks of traditional design procedure ba sed on experience and ensure the global stability and robust performance of the flight control system. Simulation were constructed on an airplane model, the res ults indicates that the design method is feasible and robust to unmodeled dynami cs.
Interval Perturbation Method for Computing Regions Containing Complex Natural Frequencies of Structures
Qiu Zhiping, Wang Xiaojun, Ma Yi
2003, 29(5): 406-409.
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By interval mathematics, the problem on regions contain ing complex eigenvalues for structures with errors or uncertain but bounded para meters was studied. These parameters were described by interval numbers. The non -proportional damping structural eigenvalue problem with errors or uncertain bu t bounded parameters can be transformed into the generalized eigenvalue problem of interval matrice s, and the complex eigenvalues are regions containing natural frequencies of str uctures with errors or uncertain but bounded parameters. For small errors or unc ertain but bounded parameters, the interval perturbation method was presented fo r computing complex interval eigenvalues of the generalized interval eigenvalue p roblem, and the required regions containing natural frequencies of structures ma y be obtained.
Analysis and Study Dynamical Characteristics of Control System of Small Coaxial Helicopter
Feng Yachang, Li Shengjun
2003, 29(5): 410-414.
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Not only practical mathematics model of longilndinal system was established for small coaxial helicopter remotely, but also the dynamical characteristics and th e influence of parameter change were analyzed. By experiment and flying tes t data, the model is proved to be correct, belivable, and its pr ecision corresponds with the demand of engineering.
Design of Differential Game Controllers Using Adaptive Critic Neural Networks
Zhou Rui
2003, 29(5): 415-418.
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An adaptive critic structure including three neural networks was developed to so lve the two point boundary value problem of differential games．Two control neur al networks were used to optimize the controllers on two sides of the differenti al games,and a co-state neural network was used to approximate the co-state v ariables in Hamiltonian function．The output of co-state network was used to correct the output of the control networks,and the two convergent control netw o rks can be used as feedback controllers on two sides of the differential games s ystem repectively．The solution of differential games based on neural networks w a s compared with the one based on Chebyshev technique．The simulation results of the pursing-escaping differential games show that the neural network controller s are consistent with the optimal solution and present good robustness with resp ect to the initial conditions and measuring noises．
Study of Microbiologically Influenced Corrosion of LY12 Aluminum Alloy with Atomic Force Microscopy
Li Songmei, Liu Jianhua, Wu Hao
2003, 29(5): 419-423.
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Sulfate-reducing bacteria induced corrosion of aluminum alloy LY12 was investig ated by using atomic force microscopy, as a function of concentrations of Fe 2+, Cl-, SO2-4 ions of the test solution. With in creasing Fe2+ concentration, the corrosion of LY12 alloy was obviously pro moted. Similar effect was observed with the addition of Cl- into the solution. The SO2-4 ion exhibited a promoting effect on corrosion at lo wer concentration and a reduced effect at higher concentration. According to th e result with AFM, the data measured by electrochemical method can be confirmed and showed, and the effect of Fe2+, Cl-, SO2-4 ions can be demonstrated by atomic force microscopy(AFM).
Graphic and Automatic Tactical Missile CFD Systemic Platform
Yan Chao, Zhang Lixin, Li Tinghe, Long Yaosong
2003, 29(5): 424-427.
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A completed tactical missile systemic platform which succeeded in full graphics user interface, automatic grid generation and CFD technique was introduced here in. This platform mainly bases on mixed-languages programming technique s of visual basic and fortran, with a vast employments of database. By all of these techniques, the excellent was given characters in easy usage for engineers. This platform was succeeded in many applications in the aeronautic a nd astronautic departments.
Control Law Reconfiguration under Control Surface Failure  for Nonlinear Aircraft Dynamic
Li Weiqi, Chen Zongji
2003, 29(5): 428-433.
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The application of pseudo-inverse method based flight control reconfiguration i n the 6 degrees of freedom aircraft model was introduced. The failure considered here is the control surface effectiveness loss or lock-in-place. Via the appro priate linearization of the control coefficients, the reconfiguration problem wa s simplified to a problem of solving a linear equations. The real-time digital simulation results were given to indicate the validity of the algorithm.
Constructing Streamlines in 3D CFD Flow Field
Li Haisheng, Yang Qin, Chen Qiming
2003, 29(5): 434-437.
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Streamline construction is a technique for flow visual ization. To avoid the conversion from physical space to computational space, a f ast point location algorithm for constructing streamline based on the normal of tetrahedron was proposed by dividing the curvilinear grids of CFD comp utation into tetrahedrons and the "wing patch" data structure was adopted to set th e topological relationship among the tetrahedrons. An adaptive step was also use d for fasten the numerical integration process. The presented method was demonst rated to be able to construct streamlines in a physical space directly, with imp roved efficiency and precision of streamline constructing.
Construction of Free ImageBased Virtual Space
Qi Yue, Shen Xukun, Zhao Qinping
2003, 29(5): 438-442.
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The important research field of virtual reality (VR)is how to construct image-b ased virtual space by image-based rendering techniques. How to enlarge the extent of freedom is the key issue. Free image-based virtual space (FIBVS) is a kind of this virtual space where users can manipulate freely. A method called conspherical mosaics to construct FIBVS was presented, and user s could look down and look up freely when they walk in it. The idea of hyperlink was used to organize those virtual objects so that users could manipulate these objects in FIBVS. The experimental results show that users can manipulate space freely in FIBVS.
Single Runway GHP Model Research Based on DES
Luo Xiling, Zhang Qishan
2003, 29(5): 443-446.
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A new single runway ground-holding problem (GHP) model based on discrete-event system (DES) was presented. According to the different con ditions influencing the airport runway landing service time, the model was categ orized into the deterministic type and the stochastic type. The solving algorith ms were given. The runway landing service time, the cost rati o between the airborne delays and the ground-holds were analyzed. Th e complexity of this algorithm was compared with the conventional algorithms. Si mulation experimental results were presented to demonstrate the effectiveness of the algorithms. This algorithm was applied to the air traffic flow estimation sy stem of the air force.
BOM Management Based on SSPD
Jiang Hui, Fan Yuqing
2003, 29(5): 447-450.
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It is a critical problem to manage all of the BOMs in the product li fe-cycle in product data management. The key of BOM management is the data mode l of BOM, as is to establish the relationship between BOMs. By analysis of the BOM from the view of product life-cycle, the BOM evolvement theory was establi shed, and a framework model for BOM management based on SSPD was given.
Scene Matching Algorithm Based on Similarity SecondOrder Difference
Huang Xishan, Chen Zhe
2003, 29(5): 451-454.
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An algorithm was presented, in which the minimum of second-order difference of similarity surface was adopted as the criteria of the selec tion of scene matching points, on the basis of analyzing the characteristics of scene matching similarity surface. The trustability of the matching point can be further determined by means of above criteria. The experimental results show th at this algorithm is effective in improving the matching probability compared wi th the traditional methods, for example the ma tching probability improves from 92.7% to 98.1% in this experiment. The confiden ce levels give a good representation of the matching point evaluation, and can b e used as a kind of reference standard for eliminating of mismatching points.
Generation of Reliability Test Data with UML for RealTime Embedded Software
Ai Jun, Lu Minyan
2003, 29(5): 455-458.
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Real-time embedded software, such as the navigation and the flight control syst ems, requires large amount of testing to measure their reliability according to the ultra-high reliability requirement. A united model language(UML)-based rel iabilit y test data generation method for real-time embedded software was presented, wh ich consists of use-case profile, interface model and test data model. The so ftware functions tested was analyzed by a use-case frofile; The interface of em bedded software was described by an interface model; The sof tware operational profile was depicted by a test data model. Based on the three models, the reliability test data for the real-time embedded software can be generated b y random sampling. With this method, the tool for software reliability test data generation can be developed and this method is of practical value in soft ware reliability testing.
Selection of Catalysts Used in the Preparation of WaterSoluble Phenolic Resol Resin
Yang Guang
2003, 29(5): 459-462.
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The effect of the kinds of basic catalysts on the preparation of water-soluble phenolic resol resin was investigated. The water-soluble resol was prepared by the reaction between phenol and formaldehyde with molar ratio 1:1.2~1.5 in the presence of catalysts at 80~85℃. The catalysts were made up of a kind of tertiary amine and a small amount of barium hydroxide. Free phenol content a nd free formaldehyde content in the water-soluble resol were not more than 10% and 1.4% respectively. This water-soluble resol is widely used in many applica tions such as plywood and insulation laminate.
Study on Residual Propellant Vaporized in Tank  of Some Launch Vehicle Third Stage
Sun Bing, Fang Jie, Zhang Huazhao, Zhang Fuzhong
2003, 29(5): 463-466.
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A zero-dimensional model was proposed to study on residual propellant vaporized in tank of some launch vehicle third stage. The assumptions used in the model and equations were given. By simulating the vaporization of cryogeni c propellant under given solar radiation angel, the variation of gas temperature, pressure and mass in tank, as well as ingoing heat flow and exhaust thrust, were calculated. A brief analysis of the rocket velocity change due to exhaust th rust shows the influence is inconsiderable, and the numerical results might be u seful to study the passivation technology of the launch vehicle further.
Evaluation System of SinkingResistance for AutoBody Sheet Material
Li Dongsheng, Zhou Xianbin, Lü Xiaodong, Wang Chengpu
2003, 29(5): 467-470.
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The sinking-resistance is one of the important performance properties of automo bile panel. The evaluation methods of sinking-resistance for auto-body sheet w ere proposed and some key factors were introduced, which include test principle, shapes/status of specimens as well as evaluating parameters of test r esults.The special test machine for evaluating sinking-resistanc e was developed, which is controlled by micro-computer. Its struc ture, measurement and control system as well as loading system were described. The application in the factory indicates that the test results are stable and relia ble.

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