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2006 Vol. 32, No. 09

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Experimental investigation on RCS characteristics of rotating blades
Meng Zhijun, Wu Zhe
2006, 32(09): 1003-1006.
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The high frequency backscattering by rotating skew-plated metal blades was investigated experimentally. RCS(radar cross section) was measured in an anechoic chamber. The RCS spectra, relating to Doppler effect, was obtained by FFT(fast Fourier transform) from time-domain signature. The effects on RCS characteristics of blade number, angle of incidence, frequency, polarization, and rotating velocity were also analyzed.The main characteristics are the periodic fluctuating of time-domain RCS and the asymmetric of RCS spectrum. The latter is due to the difference between the scattering by advancing blades and retreating blades. The results agree well with the computational analysis of previous literatures, and may do some help in helicopter detection and identification.
Entropy generation minimization analysis for aircraft environmental control system optimal design
He Jun, Zhao Jingquan, Yuan Xiugan
2006, 32(09): 1007-1010.
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A new method bases on the second law of thermodynamics for entropy generation minimization analysis and thermodynamic optimization in the research and design of aircraft environmental control system (ECS). The chosen example is a military aircraft ECS with an air cycle machine (ACM) and a counter-flow heat exchanger. The effect of some design features for ECS entropy generation was discussed, such as the efficiency of heat exchanger and turbine in ACM, the air steam pressure and temperature of bleed from air-fighter engine compressor, and the air temperature of delivery to the cabin and comfort the pilot. Numerical results show that the temperature of the air stream that the ECS delivers to the cabin can be optimized for system operation at minimal entropy generation, when the components geometry parameters are fixed. The method illustrated is applicable to more complex and realistic aircraft environmental control systems.
Calculation method of critical radar cross section of low pulse repetition frequency PD radar
Ma Dongli, Luo Xun, Pei Xu
2006, 32(09): 1011-1014.
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A solution to the problem of calculation on critical radar cross section (RCS) of low pulse repetition frequency (LPRF) PD radar was given. The critical elevation method was adopted to deal with the unknown radar parameters, and combine those parameters into a radar character constant. When the target′s signallocated in sidelobe clutters area, the problem was dealt with by treating the sidelobe clutters of LPRF PD radar as noise. While the target′s signal located in main beam clutters area, the problem was dealt with by adding the equivalent clutters RCS into the critical RCS of sidelobe, the displaced phased center antenna(DPCA) technology′s effect on critical RCS was considered too. All of which complete the critical RCS calculating method in the whole spectrum of LPRF PD radar, and the method could be used to solve the problem on detection probability of target. At last, an example of E-2C detecting a target was given.
Time-domain response analysis of a tethered aerostat
Zhang Xiangqiang, Gu Yidong, Jiang Luhua
2006, 32(09): 1015-1018.
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To stability analysis of the tethered balloon, a three dimensional nonlinear mathematical model of tethered aerostat was assembled. The tether was modeled using finite difference approximation. The balloon was modeled using rigid-body dynamic model including the static derivative, dynamic derivative and added mass. The coupling equation was assembled with the boundary condition of attached node and the initial condition of static. The time-domain response analysis was given by solving the nonlinear partial differential equations directly. The longitudinal and lateral stability was investigated by inputting step wind. The response curves of time domain also were output. The success of solving the nonlinear proved that the mathematical model is feasible.
Aerodynamic-stealth design of conformal fuel tank
Huang Minjie, Huang Jun, Wang Guanlin, Wu Zhe
2006, 32(09): 1019-1022.
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Based on the prediction of the influence of aircrafts′ stealth and aerodynamics characteristics by conformal fuel tanks, the method of aerodynamic-stealth design of conformal fuel tanks through a design model was studied, and the effects were compared with the traditional auxiliary tanks. Results show that the conformal fuel tanks bring less bad effects than the traditional auxiliary tanks in the same condition. If well designed, the conformal tanks could improve the performances of the aircraft rather than worsen them. In the designing, the research on the position where conformal tanks placed and the effects was conducted. The experience could be easily extended to other conformal carryings and other type of aircrafts. The rules of aerodynamic-stealth design of conformal fuel tanks were concluded. Based on these results, combined with the characteristics of other carryings, the principles and characteristics of the design of ordinary conformal carryings were also given for consult.
Monte Carlo method for system reliability evaluation using reliability confidence distribution
Zhang Yan, Huang Min, Zhao Yu, Yu Dan
2006, 32(09): 1023-1025.
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A Monte Carlo method was presented to ravel out the system reliability estimation problem of large and complex system′s reliability, which is a hot and difficult spot in the reliability engineering field. The reliability samples of system′s units from their reliability confidence distribution and system′s reliability estimation equation were combined in the method to simulate system running and get the system′s reliability. The difficult problem that no solution to get time samples from the discontinuous distributions is resolved by this method. Further more, the method has little limitation to the system′s structureand complexity that will expand its utilization. An instance was given to illustrate the method′s accuracy and availability in the estimation in a complex and large system through comparison with other reliability estimation methods which were generally use in the reliability engineering field.
Engineering system health formulation and health monitoring based on GFRF approach
Gao Zhanbao, Li Xingshan, Liang Xu, Yu Jinsong
2006, 32(09): 1026-1030.
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The health management concept was burgeoned as the application of engineering system. Several basic formulation definitions, such as health vector, health index, health function, were presented to mitigate the lack of formal concepts for the system health. Compared with the traditional condition parameters based component health description method, the engineering system level health condition can be effectively represented and the dynamic essence of health decrease can be revealed by using the health formulation definitions. Employing the Volterra series system description approach and analyzing the system through generalized frequency response function(GFRF), the system health vector was constructed based on the concepts of engineering system health, and the health of a kind of nonlinear system was monitored by the GFRF method. The nonlinear spring-mass-dashpot system was used as the research object. The relation between system health monitoring data and health index was given through simulation. And the simulated data show that the system health formulation definitions are effective and the system health monitoring approach based on GFRF is feasible.
Image quality assessing model by using neural network and support vector machine
Tong Yubing, Zhang Qishan, Chang Qing, Qi Yunping
2006, 32(09): 1031-1034.
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Pear signal to noise ratio(PSNR) and structure similarity(SSIM) as two indexes describing image quality were used with neural network(NN) and support vector machine(SVM) to set up new effective image quality assessing model. The definition of isolated points and the prediction of isolated points were illuminated. NN was used to obtain the image quality assessing mapping functions and SVM was used to classify the samples into different types. UTexas image database was used in simulation experiment. With the same level of consistency of quality assessing model, the prediction monotonicity of the model is 7.42% higher than PSNR. The root mean square error (rmse) of the model is 36.06% higher than PSNR. The number of isolated points with the new model was reduced and the performance of the model was enhanced. The results from simulation experiment show the model valid. The output of the new model can effectively reflect the image subjective quality.
Approach of range ambiguity suppression for spaceborne SAR based on LCMV algorithm
Yu Ze, Zhou Yinqing, Chen Jie, Li Chunsheng
2006, 32(09): 1035-1038.
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The range ambiguity suppression is a key problem in the design of the spaceborne synthetic aperture radar(SAR) system. Increasing the antenna height can solve this problem. But usually the satellite platform can not load the large antenna, which restricts the size of the antenna. The importance of suppressing the range ambiguity for observing the wide swath and producing the high quality radar image was pointed out. The mathematical model of the range ambiguity was described and a new concept was presented, i.e., the distributed range ambiguity signal ratio(DRASR). The difference between the average range ambiguity signal ratio(ARASR) and the DRASR was analyzed. An approach of the range ambiguity suppression for the spaceborne SAR based on the linearly constrained minimum variance(LCMV) algorithm was proposed. Simulation results prove that this approach not only increases ARASR, but also improves DRASR under the condition that the antenna height is not needed to be changed.
Design of a high-performance microstepping driver for two-phase stepping motors
Zhang Qinling, Li Yanming, Guo Hong
2006, 32(09): 1039-1042.
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Based on mixed-signal ISP flash MCU C8051F005 and full-bridge pulse width modulation(PWM) integrated circuit 3955, a microstepping driver with high performance, simple structure and ultra small size was designed for two-phases hybrid stepping motors. The driver utilized advanced sinusoidal current subdivided technique and fixed off-time PWM current control. Adjustable mixed current decay mode optimized the output current further. The stepping motor system provided selectable subdividing up to 256, and offered functions including direction control, half current control, enable/disable option, etc. It also had the ability of simulation and update program on system. In addition, over voltage, under voltage, over current and over temperature protections were also included for the driver′s high reliability. System design, generation of reference voltage for the phase current in different resolution and armature current control technique were detailed descried. The experiment results confirm that the microstepping driver has the characteristic of high performance, high reliability and good torque/frequency characteristic.
Slots allocation in CDM GDP
Zhou Qian, Zhang Xuejun, Liu Zhongkan
2006, 32(09): 1043-1045.
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When encounters bad weather, airport capacity is far exceeded by the demand and the resulting delays are a financial and psychological burden for airlines and passengers. CDM(collaborative decision making) GDP(ground delay procedure) is the right Air Traffic Flow Management procedure to settle such special problems. To its main problem-slots allocation, a delay cost coefficient was introduced to current two algorithms. Then two new method had been put forward to handling this problem. In the end, an experimental simulation was done in java language. By using a evaluation function, one can easily find out the best result which meet the decision maker′s request both in total delay cost and equity.
Design of extended video encoder with pre-processing of interlace signal
Yao Chunlian, Li Wei, Meng Qinglei
2006, 32(09): 1046-1050.
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Video coding stands gives out several coding methods for interlace signal. However, many kinds of macroblock division methods for motion estimation, which makes these methods very time-consuming and can′t be used actually. So an extended video encoder was designed, motion-adaptive de-interlacing was used to convert interlace signal into frame signal, then encoding frame signal with the fixed frame method. There are three steps for signal converting. Firstly, motion detection by utilizing four field signals with the same parity to get motion status of pixel, secondly, according to the motion status of pixel, use different filter to interpolate the pixel, thirdly, interlace interpolation field and current field to get progressive frame. The experimental result shows that it can get the same peak signal noise rate as MBAFF, but the encoding time is about 1/3 of other methods. What′s more, when displayed on progressive screen, it can solve the problem such as line crawling etc.
Numerical reflection analysis of PML absorbing boundary in 3-D GA-A3DI-FDTD method
Zhang Yan, Lü Shanwei
2006, 32(09): 1051-1054.
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Attention was focused on a new method to reduce the numerical dispersion of the 3-D ADI-FDTD (three-dimensional alternating-direction implicit finite-difference time-domain) method through artificial anisotropy. First, the numerical formulations of the 3-D ADI-FDTD method were modified. Second, the new numerical dispersion relation was derived. And consequently the relative permittivity tensor of artificial anisotropy could be obtained by the AGA (adaptive genetic algorithm). In order to demonstrate the accuracy and efficiency of the 3-D GA-A3DI-FDTD (genetic algorithm artificial anisotropy ADI-FDTD) method, a hollow waveguide was simulated as an example. Both the relative phase velocity and the numerical reflection of PML (perfectly matched layers) absorbing boundary were investigated for different objective functions of the AGA. And the numerical results of the proposed method were compared with those of the conventional 3-D ADI-FDTD method. It is found that this new method is more accurate and efficient.
Digital modeling of double press axial piston pump and its thermal analysis basing on AMEsim
Lu Ning, Fu Yongling, Sun Xinxue
2006, 32(09): 1055-1058.
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Hydraulic system simulation model of double press axial piston pump was established in AMESim. Movement function, flux function and swash plate model of axial piston pump were created, and carried on the corresponding simulation computation. Control valve simulation model of double press axial piston pump was established in AMESim, and the analysis emphasis were the flux characteristic and the pressure cut dynamic characteristic under two pressures. To compare the result of temperature rise, a complete hydraulic systems was established for double press axial piston pump and fix press axial piston pump under two kinds of hydraulic pump sources in the same load, the same radiation environment and the same running time. Simulation results show that dynamic characteristic of double press axial piston pump match the theory, the efficiency exceeds fix press axial piston pump.
Modeling and characteristics analysis of redundant direct drive servo actuating system
Jin Hongtao, Jiao Zongxia, Li Chenggong, Zhou Rusheng
2006, 32(09): 1059-1062.
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To improve reliability of the digital direct drive servo actuating system, the system was configured redundantly with the electrical components of three redundancies and the mechanical components of two redundancies. Redundancy configuration and management scheme of the redundant servo actuating system were designed. Mechanism of the actuating system was researched thoroughly. Mathematical models of components of the actuating system such as duplex redundancy valve controlled cylinder and triple redundancy motor were built up. Then effects of the redundancy control on the reliability and characteristics of the system were analyzed. Matlab based simulations to the redundant actuating system were performed. Simulation results show that the redundant actuating system maintains good dynamic characteristics after secondary electrical failure and one mechanical failure. Redundant configuration improves reliability and characteristics of the system. It provides theoretical bases for the design of redundant digital direct drive servo actuating system.
Key techniques of information retrieval from science and technology resources
Zhang Hui, Wu Hui, Liu Rui, Zhou Gang
2006, 32(09): 1063-1066.
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In order to search and utilize science and technology resources, which are usually distributed, hybrid, complex and massive, with high efficiency, some measures were provided on how to organize, represent, transmit and access these resources. A three-layer architecture, which consisted of data layer, data-link layer and presentation layer, was designed to make the retrieval system more open and extensible. The metadata was utilized to organize and present different types of science and technology resources. Directory service mechanism based on LDAP(lightweight directory access protocol) was used for science and technology metadata storage and accessing. In order to analyze and optimize the performance of data querying, the multi-level buffer mechanism and the query result sorting model were introduced. In our proposed solution, the responding speed of the retrieval system is improved significantly, and the system is also able to return the query result sorted by the value.
Application of wavelet network for induction motor in direct torque control system operating at low speed
Liu Lin, Shen Songhua, Liu Qiang
2006, 32(09): 1067-1071.
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To improve the low-speed dynamic performance of induction motor DTC(direct torque control), a novel method of stator resistance identification based on WN(wavelet network) was presented. The inputs of the WN were the current error and the change in the current error and the output of the WN was the stator resistance error. The synthesized method of ROLSA(recursive orthogonal least squares algorithm) and improved Givens transform was used to fulfill the network structure and parameter identification. By the use of wavelet transform that accurately localized the characteristics of a signal both in the time and frequency domains, the occurring instants of the stator resistance change could be identified by the multi-scale representation of the signal. Once the instants were detected, the accurate stator flux vector and electromagnetic torque were acquired by the parameter estimator, which made the DTC applicable in the low region, and the inverter control strategy was optimized. The simulation results show that the proposed method can efficiently reduce the torque ripple and current ripple, and is superior to the BP(backward propagation) neural network.
Design and analysis of based on PNN and FNN controller
Wang Kai, Wang Zhanlin, Fu Yongling, Qi Xiaoye
2006, 32(09): 1072-1076.
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Fuzzy neural net(FNN) and predictive neural net(PNN) are new neural net controllers, two neural net controllers based on practical methods from actual control system and self-study. FNN and PNN controllers avoid many shortcomings of usual artificial neural net. Two neural nets for electronic-hydraulic simulating rotary-table′s middle gimbal were used to research their control characteristics and application ranges.FNN controller unites fuzzy control experiences and neural net self-study capability, but control precision only depends on summarize personal experiences; PNN controller uses nonlinear auto regressive moving average (NARMA) model for predictive model, makes real time study and control for all process,but control precisions is lower in start phase. Simulation results of FNN and PNN controllers show that differnet methods for different control objects or unit two methods for different control objects have achieved high precisions.
Parallel algorithm realization of high range resolution radar based on multi-processor
Fan Xiaobo, Zhang Yongjie, Wang Jun, Li Shaohong
2006, 32(09): 1077-1082.
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An advanced real-time pulsed Doppler-pulse compressed radar signal processing system that managed to track targets with high velocity was implemented based on 8 ADSP- TS201 TigerSHARC processors. System structure designing was discussed, including DSP(digital signal processors) topology, communication, synchronization and control. In parallel system, it is crucial to optimize the mapping of problems onto parallel execute units of specific hardware platform. When implementing effective algorithm mapping, various factors were considered, such as algorithm complexity and resolvability, hardware process and real-time capability, and CPU load balance of communication and calculation tasks. Parallel design and optimization on both system and instruction levels were emphasized, while realizing system level optimization. Also parallel pipeline designing methodology was presented, including the pipelines both inside and between DSPs. With regard to the instruction level optimization, several parallel mechanisms such as SIMD(single instruction multiple data), static superscalar, BTB(branch target buffer) and space-time tradeoff were studied to optimize the system with extremely high performance, which was proved by the field experiment results.
Forming limits for as-quenched aluminum alloy sheet
Gao Hongzhi, Zhou Xianbin
2006, 32(09): 1083-1086.
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FLD(forming limit diagram) was influenced by the material properties as well as forming process, such as strain path and heat-treatment states, etc. Some experimental FLDs were constructed for 2D12 aluminum alloy in the annealed, pre-strained and various aging time conditions after solution heat-treatment by rigid punch bulging. Based on the experimental results, the FLSD (forming limit stress diagram) was determined. By comparing and analyzing the FLD and FLSD, it is indicated that the FLD of annealed condition is higher than the FLD after heat-treatment and the aging hardening lowers the FLD. The results mainly dependon the metallurgical structure transformation during solution heat treatment and the decrease of hardening value n with aging. Furthermore, aging hardening lowers the FLSD mostly because it lowers the FLD. The result may be available for the sheet forming process design and numerical simulation.
Design of bionic flapping mechanism and its kinematic analysis
Jia Ming, Bi Shusheng, Zong Guanghua, Xu Yicun
2006, 32(09): 1087-1090.
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Bionic flapping mechanism aims at realizing flapping motion of insect wings. It has become clear that two-degree-of-freedom flapping motion harmoniously is necessary for insects to produce enough lift. Double four-bar linkage mechanism and differential planetary gear train are two elements of bionic flapping mechanism, and its design, implementation, and testing were made. Driven by servo-actuator, double four-bar linkage mechanism transfers rotary motion to two sets of oscillating motions, then differential planetary gear train transfers oscillating motions to insectlike flapping motion of plunging and pitching. Mechanism kinematic analysis were made and linkage parameters and gear ratios were determined for implementing perfect flapping motion. Then instantaneous stroke angular position and angle of attack of the wing were plotted with respect to a complete alternation of upstroke and downstroke.
Quadratic surface fitting and uncertainty analysis of fitting parameters
Zhang Xi, Hu Chunhua, Chen Wuyi
2006, 32(09): 1091-1095.
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The quadric surface fitting through cloud points was described as the constrained nonlinear optimization. The calculation of initial fitting parameters and optimization algorithm were summarized, and then the influence of point coordinate measurement error on fitting parameters and evaluation of surface contour was researched. The methods to assess their uncertainty through analysis and Monte-Carlo simulation were discussed. It was found that the uncertainty of fitting parameters and surface contour could be evaluated reliably only through Monte-Carlo simulation for measurement data from actual surfaces. The simulation and actual measurement experiments were conducted, which suggested that the methods of quadric surface fitting and uncertainty assessment presented be correct.
Process examination system of aircraft sheet metal parts based on KBE
Ao Yonggang, Wan Min, Li Xinjun
2006, 32(09): 1096-1099.
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Because the sheet formability rests with various factors, the process examination of sheet metal parts is very complicated. The scientificity, rationality, veracity and reliability of process examination are the main factors in the aircraft design and manufacture. The importance of using the knowledge based engineering(KBE) technology in the process examination was put forward by means of analyzing the actuality of process examination for aircraft sheet metal parts. The general structure and realizing scheme of the process examination system were analyzed based on the database and knowledge base, and the key techniques and solution methods were studied during establishing this system. According to the example, the reliability and the function of the system were justified.
Experiments on dynamic dehumidification of internally cooling compact solid dehumidifier
Zheng Yi, Yuan Weixing, Wang Hai, Yuan Xiugan
2006, 32(09): 1100-1103.
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An internally cooling compact solid dehumidifier was built and studied experimentally. Silica gel as the desiccant was coated to all the surfaces of primary process airflow channels of the dehumidifier. Experiments on performance of the dehumidifier with and without secondary cooling airflow were carried out under both humid and less humid conditions. The experimental results show that this new type of solid dehumidifier has excellent performance with secondary cooling airflow under both conditions. At humid conditions, the outlet moisture content and temperature of the primary airflow with secondary cooling are both lower than that without secondary cooling. The dynamic water vapor adsorption ratio of the silica gel within the dehumidifier reaches 12.4% after 20 minutes that is higher than currently known performance of silica gel dehumidifier.
New manipulator calibration method based on screw theory and distance error
Tan Yuesheng, Sun Hanxu, Jia Qingxuan, Shao Zhiyu
2006, 32(09): 1104-1108.
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Accuracy of a manipulator is determined by its ability to position and orient its end-effector at the desired point in its workspace. It must be calibrated in order to improve its position accuracy. Kinematic model and the disturbance of exterior error are critical to the manipulator calibration. The effect of the manipulators′ initial orientation error on calibration was analyzed withdifferent kinematic model. A new mathematical model for manipulator calibration, which makes use of screw theory and distance error model, rather than conventional Denavit-Hartenberg(D-H) parameters and position error, was proposed. Based on the new model, the initial orientation errors of the manipulator were included thereinto. The nature drawbacks of D-H parameters in which small errors in theactual structure do not result in small changes in the kinematic parameters were avoided. The error resulting from the transformation between a measurement device frame system and a manipulator frame system was eliminated, and the difficulty in measurement technology could be overcome. Simulation was made to verify the correctness of the model.
Thermal analysis for dynamic behavior of microcellular polycarbonate
Lu Zixing, Zhang Hui
2006, 32(09): 1109-1112.
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The dynamic behavior of microcellular polycarbonate for different densities at different temperatures and frequencies was investigated by means of dynamic mechanical thermal analysis. The relations of storage modulus and loss factor with temperature, frequency and density were discussed at the same time.Furthermore, the relation of glass transition temperature of microcellular polycarbonate with density was also discussed. The results show that when the microcellular polycarbonate is at high frequency or low temperature, the storage modulus is decreased and the loss factor is increased with increasing temperature. Meanwhile, when the temperature is higher than the glass transition temperature of microcellular polycarbonate or the frequency is very low, the storage modulus and the loss factor are decreased significantly with increasing temperature or decreasing frequency . In addition, the experimental results also show that the glass transition temperature of microcellular polycarbonate is about 175℃ and the secondary transition temperature of microcellular polycarbonate is in the range of 70~100℃, which almost have nothing to do with density.
Fast reconstruction method based on C-arm tomosynthesis
Zhang Lijun, Liu Wenyong, Wang Tianmiao, Hu Lei
2006, 32(09): 1113-1116.
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As the traditional tomosynthesis is not appropriate for C-arm based slice reconstruction, a modified tomosynthesis method, CTS(C-arm based tomosynthesis), was proposed. CTS method rotates and overlays all the X-ray projections in 3-D space according to the mapping matrices of different angles, which can getfrom the geometry of the C-arm. This method can be used for the limited-angle cone-beam reconstruction, which is very suitable for isocentric C-arm imaging. The algorithm simulations with projections of a hollow sphere and two hollow-cylinder models show good image quality and demonstrate CTS has high precision. The reconstruction from projections with noise was also conducted. The results show that CTS is noise-insensitive, which validates the feasibility of the method for C-arm 3-D imaging. Finally, the process that makes CTS method adapt to the non-isocentric C-arm was proposed.
Application of maturity in development of aircraft integrated process
Tao Jian, Fan Yuqing
2006, 32(09): 1117-1120.
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Improving the level of integration of aircraft design and manufacturing has become a necessary to meet the market requirement of modern aircraft and to avoid the maximum risk of technology and quality. The importance of maturity technology was emphasized and the definition of maturity was confirmed based on integrated process and digital product model(DPM) approach. Two key technologies of DPM′s maturity and milestone were proposed referring to Boeing and Airbus ideas.The management and control method of DPM′s maturity and the process of its application in integrated process were studied in detail. Associated with module product structure and the enterprise actual capability of design, manufacturing and process, the idea of multilevel maturity was established. A case of design for manufacturing process flow was given to illustrate the validity of the idea to ensure DPM integrity and to integrate process smoothly.
Evaluation on distribution of measured characteristic with asymmetric tolerances
Zhu Wei, Li Yuansheng
2006, 32(09): 1121-1124.
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The quality of a process or product was studied based on the center of the specification interval in the conventional SPC but on target value, which led to inadequate measure of the quality under the condition of asymmetrical tolerances. In terms of this problem, the quality of a process or product was analyzed based on target value when the process was characterized by normal distribution or piecewise normal distribution. Taguchi quality loss function was applied to describe product value. To compare the process-and product-quality for the measured characteristic with the above two distributions, the expected value of product value was given. Results demonstrate that the quality of a process or product for the measured characteristic with piecewise normal distribution is better than that with normal distribution.
End-points error controlling method for torus tool position optimization in five-axis NC machining
Jin Man, Zhang Li, Chen Zhitong
2006, 32(09): 1125-1128.
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There were two points in the character-curve whose errors were equal to the required tolerance of the contour. And in the cutter surface and the to-be-machined surface, the corresponding points existed. Based on the phenomenon, a novel algorithm was brought forward. It was mainly to optimize the tool position under the condition of fixing the errors at the end-points of effective-character-curve-segment (the part of character curve within the tolerance zone). The torus cutter was first positioned by the two end-points. Then by adjusting the distance between the two points and the rotating angle around the line connected to the points, interference could be avoided, and optimization of the tool-orientation could be achieved. A program was developed to verify the validity of the algorithm in avoiding interference and realizing maximal path interval, iso-scallop tool path planning.

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