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Microstructure and Resisting Thermal Shock Behaviors of TiC-Al_2._3/Fe Functionally Graded Materials Prepared by SHS/PHIP

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Journal of Materials Science & technology 2001年第1期17卷 65-66页

作者： Weifang ZHANG Niansheng XI and Chunhu TAO institute of Aeronautical Materials, Beijing 100095, china Jiecai HAN and Shanyi DU {2. for Composite Materials, harbin institute of technology, harbin 150001, china Inst Aeronaut Mat Beijing 100095 Peoples R China harbin Inst Technol Ctr Composite Mat Harbin 150001 Peoples R China

The microstructure and composition of TiC-A12.3/Fe functionally graded materials (FGM) prepared by self-propagating high temperature synthesis and pseudo-hot isostatic pressing (SHS/ PHIP) were studied, and the resisting thermal shock behaviors were analyzed. The results show that TiC-A12.3/Fe FGM has graded composition distribution. No cross-section crack through the layers was found in the tests of thermal shock and fatigue.

关键词： functionally graded materials thermal shock graded composition high temperature

The Performance Analysis of Traffic Channel Coding in Digital Trunking System

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Journal of Systems Engineering and Electronics 2001年第2期12卷 30-35页

作者： Tan Xuezhi, Su Min & Zhang Naitong Communication Research center of harbin institute of technology, {2., P R china Communication Research center of harbin institute of technology 150001 P.R. China

The encoding and decoding processes of traffic channel in digital trunking system are studied. On the basis of computer simulation, the BER (bit error ratio) with different RCPC decoding step is analyzed. As a result, the optimal RCPC decoding step is provided, which gives essential theoretical evidences for the implementation of digital trunking system.

关键词： Bit error rate Communication channels (information theory) Quadrature phase shift keying Signal encoding Telecommunication traffic

Experimental study on a transpiration cooling thermal protection system

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Science china(Technological Sciences) 2010年第10期53卷 2765-2771页

作者： LIU Shuang & ZHANG BoMing center for Composite Materials and Structure, harbin institute of technology, {2. 150080, china 1. center for Composite Materials and Structure Harbin Institute of Technology Harbin 150080 China

Transpiration cooling thermal protection systems (TPS) are investigated for potential applications in hypersonic and re-entry vehicles,which are subjected to the severe aerodynamic heating environment. In this paper a transpiration cooling thermal protection system was designed and manufactured,and an experiment platform with radiant heating at the bottom as heat source was developed. The cooling capacity of the transpiration cooling TPS was experimentally investigated. By combining transpiration cooling method with traditional TPS,the heat load capability of the TPS can be improved. The structure temperature with active cooling applied was much lower than that without active cooling applied under the same heat load as well as the heat load increased with active cooling than the one without active cooling for the same structure temperature. The experimental results showed that at 5800 s,the temperature of inner structure was 100°C with active cooling applied compared to 500°C without active cooling applied,then the temperature increased and reached to 360°C at 8300 s. Heat load of this transpiration cooling TPS can be increased by over 70% as compared to the passion one and the cooling capability of the transpiration TPS was about 1700 kJ/kg. The results can provide fundamental data for developing the transpiration cooling TPS.

关键词： thermal protection metallic thermal protection system active cooling transpiration cooling cooling capacity

NUMERICAL SIMULATION METHODS AND THEIR APPLICATION IN MATERIAL HOT-WORKING

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Acta Metallurgica Sinica(English Letters) 2000年第2期13卷 494-501页

作者： J. T. Niu, H. T. Li, X. D. Meng and P. Karjaleinen 1) Analysis and measurement center,{2., harbin 150001, china 2. Department of Mechanocal Engineering, The University of Oulu, Finland

With the development of modern science and technology, especially computer science, the numerical simulation method has been widely used in material hot-working. Mary achievements have been made in this field by using the numerical simulation method. The numerical simulation method, especially finite element method fully described in this *** of the numerical simulation method in material hot-working are also discussed. Finally, the future of the numerical simulation method is outlined.

关键词： numerical simulation material hot-working

Channel-aware and queue-aware joint-layer resource optimization for cognitive radio networks

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Science china(Information Sciences) 2010年第12期53卷 2576-2583页

作者： GUO KunQi 1,2.SUN LiXin 1,LI Yong 2.& JIA ShiLou 3 1 School of Computer Science and Telecommunication Engineering,Jiangsu University,Zhenjiang 2.2.13,china 2.Research center for Wireless Communication,Shanghai {2. of Microsystem and Information technology,Chinese Academy of Sciences,Shanghai 2.0050,china 3 Communication Research center,harbin {2. of technology,harbin 150001,china 1. School of Computer Science and Telecommunication Engineering Jiangsu University Zhenjiang 212013 China2. Research Center for Wireless Communication Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai 200050 China3. Communication Research Center Harbin Institute of Technology Harbin 150001 China

An optimization model is derived to maximize the utilization efficiency of the idle channels of primary users(PU) in cognitive radio *** the optimization model,Lyapunov optimization method is used to allocate the idle channels of PU to secondary user(SU) most *** time distribution of the idle channels of PU is predicted by a low-pass time *** algorithm is proposed to implement the optimization *** algorithm is efficient because of using a greedy selection *** efficiency of the algorithm is demonstrated by mathematic analyses and simulation results.

关键词： cognitive radio networks Lyapunov optimization resource utilization primary user secondary user

An improved nonlinear control strategy for deep space formation flying spacecraft

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Acta Mechanica Sinica 2009年第6期25卷 847-856页

作者： Peng Li Pingyuan Cui Hutao Cui Deep Space Exploration Research center,harbin {2. of technology, 150080 harbin, china Deep Space Exploration Research center Harbin Institute of Technology 150080 Harbin China

This paper aims to provide further study on the nonlinear modeling and controller design of formation flying spacecraft in deep space missions. First, in the Sun-Earth system, the nonlinear formation dynamics for the circular restricted three-body problem （CRTBP） and elliptic restricted three-body problem （ERTBP） are presented. Then, with the Floquet mode method, an impulsive controller is developed to keep the Chief on the desired Halo orbit. Finally, a nonlinear adaptive control scheme based on Nonzero set- point LQR and neural network is proposed to achieve high precision formation maneuver and keeping. The simulation results indicate that the proposed nonlinear control strategy is reasonable as it considers not only the orbit keeping of the Chief, but also the formation modeling inaccuracy. Moreover, the nonlinear adaptive control scheme is effective to improve the control accuracy of the formation keeping.

关键词： Spacecraft formation flying. Libration pointHalo orbit - Nonlinear control

Monocular vision-based iterative pose estimation algorithm from corresponding feature points

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Science china(Information Sciences) 2010年第8期53卷 1682-1696页

作者： ZHANG ShiJie 1 , CAO XiBin 1 , ZHANG Fan 1 & HE Liang 2.1 Research center of Satellite technology,{2., harbin 150080, china 2.Shanghai Aerospace Control Engineering institute, Shanghai 2.02.3, china 1. Research center of Satellite technology Harbin Institute of Technology Harbin 150080 China2. Shanghai Aerospace Control Engineering Institute Shanghai 200233 China

To determine the relative pose between an object and a single camera using 2.-to-3D point correspondences, a kind of iterative methods based on inverse projection ray approach is proposed. An iterative algorithm which is divided into depth recovery stage and absolute orientation stage is also proposed. In the first stage, the optimal translation vector is first computed in terms of rotation matrix via least square method, then the depths of the observed points are estimated by projecting the estimated point orthogonally to the inverse projection ray defined by the image point, and finally 3D points are reconstructed using the estimated depths from previous step. In the second stage, the optimal rotation matrix is estimated by applying Umeyama algorithm to fitting of the 3D model points and 3D estimated points. The above two stages are repeated until the result converges. The global convergence of the two-stage iterative algorithm is proven based on the global convergence theorem. Finally, a spacecraft docking application is implemented to test the effectiveness and convergence of the proposed algorithm by mathematical simulation and physical simulation.

关键词： monocular vision feature point relative pose two-stage iterative algorithm global convergence

One-pot synthesis of crystalline SnO_2.nanoparticles and their low-temperature ethanol sensing characteristics

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Science china(Physics,Mechanics & Astronomy) 2009年第10期52卷 1601-1605页

作者： CHEN YuJin1,2.3,ZHU ChunLing4,WANG LiJiao3 & WANG TaiHong2.1 School of Materials Science and Engineering,Beijing institute of technology,Beijing 100081,{2. 2.Micro-Nano Technologies Research center,Hunan University,Changsha 410082.{2. 3 College of Science,harbin Engineering University,harbin 150001,{2. 4 College of Material Science and Chemical Engineering,harbin Engineering University,harbin 150001,{2. School of Materials Science and Engineering Beijing Institute of Technology Beijing 100081 China Micro-Nano Technologies Research center Hunan University Changsha 410082 China College of Science Harbin Engineering University Harbin 150001 China College of Material Science and Chemical Engineering Harbin Engineering University Harbin 150001 China

Crystalline SnO2.nanoparticles(NPs) with a diameter less than 6 nm are synthesized using potassium stannate trihydrate as the precursor in a basic *** synthesized NPs can detect ethanol at a ppm level even at 100℃.Furthermore,the NPs have good selectivity to *** excellent ethanol sensing performances are attributed to the small size effect according to the space-charge model.

关键词： SnO2 nanoparticles sensing characteristics

Scale-Invariant Occupancy of Phase Space and Additivity of Nonextensive Entropy S_q

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Journal of Shanghai Jiaotong university(Science) 2010年第4期15卷 441-446页

作者：赵伟伞冶 Control and Simulation center Harbin Institute of Technology

Phase space can be constructed for N equal and distinguishable binary subsystems which are correlated in a scale-invariant manner. In the paper, correlation coefficient and reduced probability are introduced to characterize the scale-invariant correlated binary subsystems. Probabilistic sets for the correlated binary subsystems satisfy Leibnitz triangle rule in the sense that the marginal probabilities of N-system are equal to the joint probabilities of the （N - 1）-system. For entropic index q ≠ 1, nonextensive entropy Sq is shown to be additive in the scale-invariant occupation of phase space.

关键词： nonextensive entropy additivity correlation scale-invariance