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2005 Vol. 31, No. 01

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Study of transition metal silicides thin film epitaxial growth on silicon substrate
Wang Jinliang
2005, 31(01): 1-4.
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Transition metal(TM)-silicon contact systems have received special interest because of their importance in Schottky barrier formation, epitaxial growth, device reliability, refractoriness, etc. The formation of silicides from the reaction between deposited thin metal films and Si substrates has wide application in the semiconductor industry. Transition metal silicides were grown by solid phase reaction(SPR) for thin Cr, Mn, Fe films on n-Si(100) substrate systems. The formation of silicides from the reaction between deposited thin metal films and Si substrates at thermally annealling. They were identified by either X-ray diffraction(XRD) or soft x-ray emission spectroscopy(SXES). From these results it can be concluded that those silicides’s thin films grow with single phase on the silicon substrate.
Adaptation scheme based on network testing and performance analysis
Zhang Yuqing
2005, 31(01): 5-7.
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In packet-switched IP networks, congestion perhaps is unavoidable. Therefore, it is necessary to perform congestion control for real-time multimedia service. Usually, loss rate is considered as the sign of the network congestion and AIMD is the adjustment scheme. It is difficult to obtain the optimal performance, because the parameters in AIMD scheme are fixed. An adaptation scheme TITD (testing increase and testing decrease) based on network status was proposed. When the network is in congestion, sending rate is reduced to the receiving rate obtained at the receiver. When the network is idle, the additive rate is according to the RTT. TITD is adaptive to the network status, and is superior to AIMD (additive increase and multiplicative decrease) in TCP-friendliness and rate oscillation.
Zinc alloyed coating on AZ91D magnesium alloys
Zhu Liqun, Liu Huicong, Li Weiping, Song Guangling
2005, 31(01): 8-12.
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In order to improve the corrosion resistance and micro-hardness of AZ91D magnesium alloys, its surface was treated by zinc alloys. The characterization of the above-prepared coating on AZ91D magnesium alloys was studied, andits surface image, cross-section image, XRD image, corrosion resistance abilityand micro-hardness were also researched. The anodic polarization curve and electrochemical impedance spectrum of the coating on AZ91D magnesium alloys were examined before and after the samples being zinc alloyed. All results show that the zinc alloyed coating on AZ91D magnesium alloys is uniform and fine, and it is made up of Mg7Zn3, Mg and Zn. This coating has better corrosion resistance and good protective characterization than the magnesium alloys, and it has relatively higher micro-hardness than the magnesium alloys.
Structural bionics for reinforcing frame of fuselage and wing joint
Cen Haitang, Chen Wuyi, Yu Maolin, Liu Xuelin
2005, 31(01): 13-16.
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Similarity is the base of bionics. Comprehensive explanation of functional demand in engineering prototype and superiority of biologic structures in all levels, accurate understanding the similarity of organisms and engineering prototype, these are the key of the bionic structure design. To decrease the weight of an aircraft reinforcing frame, the similarity in loading feature with bamboo and an aircraft reinforcing frame was analyzed. Based on the bamboo’s meso-structure shape and its arrange way a reinforcing frame was designed by applying the biomimetics principle. The FEA results show that the weight of the bionics frame decreased by 2.1% in ensured strength and structural stiffness compared with the original design.
Measure technology of the center of gravity of ejection seat-pilot system
Wang Xingwei, Wu Ming, Zhang Xing, Yuan Xiugan
2005, 31(01): 17-20.
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To solve the stability adjustment problem of pilot-seat system after ejecting from fight plane cabin, a new electronics equipment which can measure the combined center of gravity of pilot-seat system was designed and manufactured, a new pitching-progressive measure and calculate technique was founded, and the combined center of gravity of 294 pilots were measured. It shows that the new equipment is accurate and reliable, the technique is efficient and convenient, and they are both universal. The equipment and technique have been applied in the design and manufacture of ejection seat. It is proved that the precision is improved 10 times, while the efficiency 3 times.
Long-range air-to-air missiles combat system
Jiang Yuxian, Liu Hui, Shen Yang
2005, 31(01): 21-24.
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The effective technique approach to realize the air combat by use of long-range air-to-air missiles was studied. The communication net, which is used to get movement information of long-range targets and transmit the missile’s guidance command information, was composed of various detecting and communication means available. The net, missile carrier and the missile form the combat system that carries out attacking the long-range targets. The project of the long-range air-to-air missiles combat system was proposed. The relative mathematic model of each component was established. The influence of errors induced by information detection, transmission, fusing on combat effect was analyzed. The simulation of the combat system is completed. The results show that the project of long-range air-to-air missiles combat system is effective.
Study on characterizing streaming media and user access to media on the Internet
Cai Qingsong, Li Zimu, Hu Jianping
2005, 31(01): 25-30.
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Through tracing the log data of four typical streaming servers of CERNET, the characteristics of streaming media and its access pattern to attempt to give evidence of the key component design or simulation in streaming system such as streaming proxy in CDN were analyzed. The results show that the size and playback duration of media files fit the lognormal distribution well but the average bit rate varies in a "bi-peak" model; references to streaming media present stronger skew popularity than Zipf distribution; temporal locality of the reference is unclosed. Both the locality and temporal correlation that exists in the request stream are enclosed that it is the hot references to the few front media files of the file rank that cause the locality, while these requests present stronger temporal correlation. Implications of above conclusions in analyzing, designing and implementing the streaming cache proxy are elucidated.
Fast simulation of complex image for interferometric SAR
Li Wenqiang, Li Jingwen, Chen Jie
2005, 31(01): 31-35.
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To validate the capability of interferometric algorithm and give useful complex INSAR data for INSAR study, a new method of INSAR (interferometric SAR) simulation was carried out. As the backscattering coefficient and thermal noise and other factors were concerned, a model of simulation of INSAR based on complex image was deduced; also a new method used to determine the slant distance accurately was analyzed and given. With this method, complex image data for interferometric SAR can be generated fast and effectively, and high-quality phase interferograms without break points can be obtained conveniently. This model can produce data for registration and phase unwrapping, and baseline estimate method can also be validated with the data. The results of simulation on computer show that the new model is capable and accurate; the new method to determine the slant distance is fast and effective.
Implicit model following technique for aircraft configuration with multiple control surfaces
Zhou Jie, Zhang Shuguang
2005, 31(01): 36-40.
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The implicit model following technique, based on linear quadratic theory, was applied to design the flight control augmentation system (FCAS) of an aircraft with multiple control surfaces. The selection philosophy for the ideal model was investigated, which is based on the flight dynamics and the flying qualities requirements. The closed-loop design schemes were evaluated according to command following accuracy and ability to subdue effects of the atmospheric turbulences and other disturbances, where the structured singular value analysis method was adopted to evaluate robust stability and robust performance of the FCAS. The results show that the designed FCAS can subdue the turbulence and has good robust stability and adequate robust performance.
Analysis on reach envelop of pilot in cockpit
Wang Lijing, Yuan Xiugan, Li Yinxia, Wang Yongqing
2005, 31(01): 41-44.
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The method to obtain reach basket envelopes data was depicted, and a model of reach basket envelopes analysis was set up. The neutral seat reference point was defined coordinate origin, then reach basket envelopes data of American air force men was converted to that of Chinese with coordinate transform. According to Chinese Military Standard, three types analysis models of reach envelope in cockpit were built. The reach ability of some controllers in one electronic cockpit was analyzed by reach envelope analysis model. Several pilots analyzed the reach ability of these controllers in the actual cockpit. The results revealed the validity of the analysis mode.
Attitude algorithm for strap-down inertial navigation system
Liu Wei, Xie Xuhui, Li Shengyi
2005, 31(01): 45-50.
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Under the condition of high dynamic angular motion or vibration environment, determining and compensating the non-commutivity vector is important tocalculate the attitude matrix of strap-down inertial navigation system. To compensate the coning error introduced by the non-commutivity vector, many custom algorithms were analyzed. Because there are so many algorithms, that the choice is hard for engineering application. Based on the inductive analysis for the principle and mathematical form of custom algorithms, a normalized algorithm was introduced to overcome it. And then, a new method was introduced. By treating the product of sampling time and angular frequency as the parameter λ, the method use the power of λ to express the error ,and can use it to estimate the accuracy of compensate algorithms. Based on this new method, by analyzing the error performances of new algorithms, some conclusions about the relationship of parameter and the accuracy of compensate algorithms were gained. And then, a standard was provided for the parameter selection. The standard can make the choice for engineering application.　　
Flight vehicles multidisciplinary design optimization software system
Wang Shuhe, He Linshu, Zhang Yuzhu
2005, 31(01): 51-55.
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In order to solve difficulties of flight vehicles overall design, a software for flight vehicles multidisciplinary design optimization was introduced. Which adopts a "loose coupling" algorithm, uses SQL Server 2000 as its data base management system(DBMS), and combines with various analytical programs of disciplines. The system function, software structure, software process and main modules were discussed. To deal with critical techniques, the ring-shaped graphical was put forward to deal with the relationship between overall and disciplines, the system fuzzy theory was adopted to transform non-numerical variables, the non-dimensional multi-object method was presented to solve multi-object, a single database was built to perform data management, and three data files were applied to program interface. The features of software were concluded. The calculation result shows that the software works effective.
Experimental research of sound excitation on flow of subsonic compressor blade profile in planar cascade tunnel
Hou Anping, Jiang Zhengli, Ling Daijun, Zhou Sheng
2005, 31(01): 56-59.
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A lot of work was done in planar cascade tunnel to validate the theory on two generations of unsteady flow type. In the first phase ,the frequency of all kinds of work condition was got. In the second phase, the method of sound excitation was used based on the frequency got forward to research the interaction between variable unsteady disturbances. Through comparing the total pressure loss,frequency spectra of flowfield’s parameter and aerodynamic parameters of unforced condition with those of forced condition, the results of research confirm that the aerodynamic performance of cascade can improved if the interaction of unsteady disturbs in the flowfield can reasonable organization.
Design on inference engine of the spacecraft thermal fault diagnosis expert system
Wei Chuanfeng, Li Yunze, Wang Jun, Yu Tao
2005, 31(01): 60-62.
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When a spacecraft is on mission, various unpredictable faults often occur. It is very important that spacecrafts should be capable of diagnosing thermal faults automatically because most of them are difficult to be repaired on orbit, which requires a credible inference engine. And many rules and cases for fault diagnosis can be obtained after the spacecraft thermal test fault analysis. Those cases are difficult to describe in exact rules, but they are the most important experience in the spacecraft test. Combined with the rule-based reasoning and the case-based reasoning, the hybrid inference engine was produced, and the corresponding conflict resolutions were given. In rule-based reasoning, similarity judgement is used to resolve the conflict, and the numerical method differs from the non- numerical one. In case-based reasoning, the method of priority, ranking and credibility can be used; and the method of ranking is preferred to resolve the conflict if the number of all the cases is little.
Virtual environment based on Internet and Java3D for multi-robot teleoperation
Gao Sheng, Zhao Jie, Cai Hegao
2005, 31(01): 63-68.
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For an internet-based multi-robot teleoperation system, two critical issues of random time-delay and multi-robot coordination were studied. For the first issue, a virtual environment, which is constructed on the basis of Java and Java3D technologies, was employed to resolve time-delay problem by only transmitting status information of remote environment, so the huge transmission of traditional video information was avoided. For the second issue, virtual-guide models were proposed and implemented, by which an operator can predicate the actions of other operators locating in other places, thus a good and valid coordination of multiple operators can be guaranteed and achieved. Two typical experiments were given to verify the reasonability and feasibility of the multi-robot teleoperation system.
Analysis of design calculation methods of scramjet combustion chamber
Wang Yuanguang, Xu Xu, Cai Guobiao
2005, 31(01): 69-73.
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To find a proper way to calculate the performance of scramjet combustor and evaluate the present methods, one-dimensional chemical dynamics method was brought forward and tested with several cases. Calculation was carried out with three different methods: impulse analysis, one-dimensional chemical dynamics and two-dimensional chemical dynamics. Based on the comparison of aerodynamic parameters in combustion chamber obtained with the above methods, results show that one-dimensional chemical dynamics method and impulse analysis method can consider the influence of friction, the variation of tunnel cross area and the heat release, so the above two methods can be used to calculate the scramjet combustion chamber, which is always easy designed in configuration. As for impulse analysis, it is necessary to set the heat release discipline in chemical reaction related calculation, whereas it is unnecessary for one-dimensional chemical dynamics method, with the internal chemical reaction model obtaining the corresponding discipline. The two-dimensional chemical dynamics method can figure out the detailed information in the flow field, with taking up too much time. It is evident that different models have different advantages, so it is valuable to make the best use of each model in different calculation situation.
Solution on fingerprint verification based on smart cards
Li Meihong, Zhang Qishan
2005, 31(01): 74-77.
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The abilities of computation and storage for smart card were utilized, the fingerprint template was not only stored in it, but also the fingerprint matching process was implemented on it, but other processes of fingerprint recognition algorithm were performed on an authenticated reader/writer. The pre-process only comprised three parts, the first was a computation of directional field based on discrete directions, then a smoothing operator and enhancing operator were used for the image enhancing along and perpendicular to the ridge of fingerprint, the last was a direct ridge tracking for feature extraction. In the matching process the parameters of rotation and displacement were obtained by two congruent triangles, then the point-pairs matching would be performed on the transformed sets. The matching time and recognition rate on smart card experimentally proved the feasibility for engineering application.
ADS and multi-radar bias registration algorithm for ATC system
Jiang Naixin, Zhang Jun, Luo Xiling, Liu Wei
2005, 31(01): 78-81.
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The data fusion model of ADS and multi-radar surveillance system in air traffic control was analyzed and an ADS and radar system bias registration algorithm using the least square(LS) technique was given based on the conventional method in the multi-radar surveillance system. The optimal solution was presented and the simulation was done based on the simulative fairway point data in the west fairway of our country. The analysis of the simulation results show that the system biases of ADS and radar data fusion system have been eliminated effectively and the surveillance precision is improved.
Image processing and analysis algorithms for measuring log volume
Long Defan, Fan Shangchun, Pang Hongbing
2005, 31(01): 82-85.
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The key image processing and analysis algorithms were investigated and designed based on operating principle of the automatic system for log volume measurement. Hough transform (HT) was applied to the image since log ends are quasi-circular. Peaks of the HT were detected in maximal balls corresponding toeach maximum skeleton point. Consequently, the image was coarsely segmented by each HT peak corresponding to one log end. The active contour model was transformed into the polar coordinates. And the maxima of image gradient were selected as candidate points of log end contour. Global minimum of the energy functional can be found using dynamic programming. With this approach, the precise contours of the log ends can be extracted. Experiment shows that the proposed algorithms are of significance.
Adaptive regulation on the thermal deformation of the panel of compact antenna test range
Wang Zhaojun, Chen Wuyi
2005, 31(01): 86-88.
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The temperature of compact antenna test range may vary from 15℃ to 25℃accompanied by the seasons. The thermal deformation often exceeds the allowed error. Its deformation under the loads of temperature、gravity and reverse force was analyzed with MSC.MARC. For the worst case, the data of the deformed points were used to form a new conic using least-square method. A new generatrix and focus of the reflecting panel that are consistent with the deformed generatrix of the penal were drawn. The results indicate that the regulation of the signal source can fit in with the variation of the focus.
Passive TDOA location algorithm for eliminating location ambiguity
Chen Ling, Li Shaohong
2005, 31(01): 89-93.
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The problem of eliminating location ambiguity in passive time difference of arrival(TDOA) systems is considered. The accuracy analysis and the simulation results of four-variable algorithm show that its performance is poor regardless of the capability of eliminating location ambiguity. Based on the traditional TDOA location algorithm, a subset fusion algorithm of multiple subsystems was presented. The proposed algorithm can fully utilize the redundant information come from passive sensors, so it not only can eliminate location ambiguity, but also improve the location accuracy. In comparison with the four-variable algorithm, subset fusion algorithm of multiple subsystems is superior to the alternative algorithm in terms of location accuracy. The simulation results prove that the new algorithm is effective and practicable.
Design of the flute grinding parameters to be produced with parallel grinding machine
Pei Baoqing, Luo Xueke, Chen Wuyi, Huang Bo
2005, 31(01): 94-97.
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The flute machining is important to produce a milling cutter. The geometric parameters (especial its rake angle,flute depth and flute width) have essential influence on the performance of the tool. Using a 6-UPS parallel machine,based on analyzing its special machining and structure features,general analysis was given for all factors which will influence of flute forming,and according to the motion relation between grinding wheel and the milling cutter,a simulation model system was established,that can optimize and quantitative design all of the parameters quickly. These parameters include the grinding wheel deflexion,the grinding wheel thickness,the grinding wheel offset position along the axes direction,and the flute depth. These parameters have been verified by experiments.
In-vehicle information platform based on GPRS
Zhang Zhengxuan, Zhang Qishan
2005, 31(01): 98-101.
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Many outstanding advantages of GPRS transmission mode was analyzed, and a novel type of in-vehicle information platform was put forward, which focused on improving modernization degree of city traffic. Also, based on the actual test status, function of the system, the frame of hardware and the implementation of software and so on were elaborated. The key technique which used to log on GPRS network were emphasized, the ways and means on how to improve the performance of system were detailed . The test result shows the data lost rate is between 5%~6% and the data delay rate is less than 1% after consummating the system. It possesses high practical value, and provides some significative theory and test results for other in-vehicle monitoring system development.
Study to optimize and distribute the cost of air spares support
Zhang Ruichang, Zhao Songzheng
2005, 31(01): 102-104.
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The primary works of air spares support include preparation, storage, supply and management, which need the sustainment of funds. Millions items of air spares will take a lot of money. It is essential for the improvement of the operational rate of air spares support and the availability of aircraft that how to make full use of optimize and distribute the funds of air spares. Taking the funds as resource, the improvement of the whole performance efficiency of air spares support system and optimizing and distributing the purchase cost of aircraft repair spares as objective, the models to optimize and distribute the cost of air spares was presented, the expressions with the marginal analysis method was deduced, the scheme to get best effect-cost of air spares support with the numerical calculate method was obtained, so as to make full use of the limited funds and obtain the highest efficiency of air spares support.
Conceptual study of magnetic launch assist system for space launch
Yang Wenjiang, Liu Yu, Yang Bo
2005, 31(01): 105-110.
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To solve the problem of ever-increasing cost of getting to space and the need for safe, reliable, and inexpensive ways to access space, a magnetic launch assist concept and its benefits were described and discussed. Primary magnetic launch assist system configuration and each subsystem functions were analyzed. By comparing the capability of electromagnetic suspension (EMS) system with that of electrodynamic suspension (EDS) system, the result indicates EDS is a more reasonable magnetic levitation system scheme applied to magnetic launch assist. The linear motor power supply system is found a difficulty after the launch assist energy requirement was analyzed, and needs to be attentively resolved. By using a general flight trajectory analysis method, the feasibility and characteristic of horizontal takeoff single stage to orbit (SSTO) vehicle with ground launch assist were shown. Having compared with other space launch assist methods, magnetic launch assist has some superiority on sending more payloads to low earth orbit and decreasing launch cost.

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