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Time/Wavelength Fiber Bragg Grating Multiplexing Sensor Array

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光学学报 2003年第S1期23卷 847-848页

作者： Shiya He, Shuyang Hu, Qida Zhao, Kuanxin yu, Jinfeng Zhou, Li Wang science College, beijing university of technology, beijing 100022, P.R. china science College Beijing University of Technology Beijing 100022 P.R. China

A novel time/wavelength-multiplexed fiber Bragg grating sensor array is presented. This type of sensor array has the advantages of more points for multi-point measurement, simple structure and low cost.

关键词： of with on be Time/Wavelength Fiber Bragg Grating Multiplexing Sensor Array have in for that

On the periodic solutions of a type of differential-iterative equations

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Chinese science Bulletin 1998年第3期43卷 204-206页

作者： GE Weigao 1, LIU Zhengrong 2 and yu yuanhong 3 1. department of Applied Mathematics, beijing Institute of technology, beijing 100081, china 2. department of Mathematics, yunnan university, Kunming 650091, china 3. Institute of Applied Mathematics, C department of Applied Mathematics Beijing Institute of Technology Beijing China department of Mathematics Yunnan University Kunming China Institute of Applied Mathematics Chinese Academy of Sciences Beijing China

Sufficient conditions for the existence of periodic solutions to a type of nonautonomous differential_iterative equations are given.

关键词： differential_iterative equation periodic solution fixed point.

TRANSESTERIFICATION OF POLY(ETHYLENE TEREPHTHALATE) WITH POLY(ε-CAPROLACTONE)

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Chinese Journal of Polymer science 2000年第5期18卷 405-412页

作者： Zheng-ping Zhang Xiao-lie Luo yu-chen Lu De-zhu Ma department of Polymer science and Engineering, university of science and technology of china, Hefei 230026, china Univ Sci & Technol china Dept Polymer Sci & Engn Hefei 230026 Peoples R China

Transesterification of poly（ethylene terephthalate）（PET） with poly（ε-caprolactone）（PCL） was investigated bymeans of NMR spectroscopy, extraction experiments, differential scanning calorimetry （DSC） and phase contrast microscopy（PCM）. The;H-NMR results show that transesterification takes place in the melt blends and leads to the formation of thePET-PCL copolyester with a chemical structure similar to ethylene terephthalate-ε-caprolactonc copolycster （TCL）synthesized directly from monomers. However, even in the blend that has been transesterified for 8 h, the random PET-PCLcopolyester, PET-PCL copolyester with long PET or long PCL segments and the unreacted PET and PCL homopolymersmay coexist. Due to the low mobility of PET and PCL chains and the high viscosity of the two macromolecules, thetransesterification proceeds with difficulty. Furthermore, PET is incompatible with PCL, the transesterification can onlyoccur at the interface or in the interfacial region between two phases, and finally the reaction can only reach a localequilibrium. These results indicate that in fact the transesterification in the melt blend between two incompatiblehomopolymers could not lead to the formation of completely random or typical block copolyesters.

关键词： Transesterification Poly(ethylene terephthalate) Poly(ε-caprolactone) Crystallization Phase structure

Scan chain design for shift power reduction in scan-based testing

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science china(Information sciences) 2011年第4期54卷 767-777页

作者： LI Jia 1,HU yu 2 & LI XiaoWei 2 1 The School of Software,Tsinghua university,beijing 100084,china 2 The Institute of Computing technology,Chinese Academy of sciences,beijing 100190,china 1. The School of Software Tsinghua University Beijing 100084 China2. The Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China

Test power of VLSI systems has become a challenging issue *** scan shift power dominates the average test power and restricts clock frequency of the shift phase,leading to excessive thermal accumulation and long test *** paper proposes a scan chain design technique to solve the above *** on weighted transition metric (WTM),the proposed extended WTM (EWTM) that is utilized to guide the scan chain design algorithm can estimate the scan shift power in both the shift-in and shift-out ***,the wire length overhead of the proposed scan chain design can also be reduced by the proposed distance of EWTM (DEWTM) *** results confirm that the proposed approach can significantly reduce scan shift power with low wire length overhead.

关键词： low power DfT scan-based testing test power reduction scan chain design

Modified vegetation-erosion dynamics model and its application in typical watersheds in the Loess Plateau

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International Journal of Sediment Research 2011年第01期26卷 78-86页

作者： CHEN yuehong~1,WANG Feixin~2,LIU Guangquan~3,yu Xinxiao~4, JIA Guodong~5,and GAN Ping~6 china Institute of Water Resources and Hydropower Research,beijing 100048 International Research and Training Center on Erosion and Sediment Research,beijing 100048,china beijing Forestry university,beijing 100083,china. Key Lab of Dredging technology of CCGRP,Shanghai Waterway Engineering Design and Consulting Co., Ltd,Shanghai 200120,china. International Research and Training Center on Erosion and Sedimentation china Institute of Water Resources and Hydropower Research,beijing 100048 Northwest A&F university,Yangling 712100,china, beijing Forestry university,beijing 100083,china, beijing Forestry university,beijing 100083,china. china Institute of Water Resources and Hydropower Research,beijing 100048,and International Research and Training Center on Erosion and Sediment Research,beijing 100048,china [a] Assoc. Prof. Dr. china Institute of Water Resources and Hydropower Research beijing 100048 International Research and Training Center on Erosion and Sediment Research beijing 100048 china beijing Forestry university beijing 100083 china [b] Dr. Key Lab of Dredging technology of CCGRP Shanghai Waterway Engineering Design and Consulting Co. Ltd Shanghai 200120 china [c] Prof. Dr. International Research and Training Center on Erosion and Sedimentation china Institute of Water Resources and Hydropower Research beijing 100048 Northwest A&F university Yangling 712100 china [d] Prof. Dr. beijing Forestry university beijing 100083 china [e] Dr. beijing Forestry university beijing 100083 china [f] Engineer china Institute of Water Resources and Hydropower Research beijing 100048 and International Research and Training Center on Erosion and Sediment Research beijing 100048 china

The vegetation-erosion model was applied in three typical watersheds of hilly and gully area in the Loess Plateau in northwestern china to study the dynamic relations between vegetation coverage and soil erosion rate and various *** model was improved by introducing rainfall and runoff *** the modified model was applied in the Luergou and Luoyugou *** calculation results with the modified model were compared with the results of the original *** precisions of simulated vegetation coverage and soil erosion rate with the modified model were greatly improved compared with the original *** erosion rate reduced with increasing vegetation coverage and the human disturbance caused high soil erosion.

关键词： Soil erosion Vegetation coverage Vegetation-erosion dynamics model Loess Plateau Modified model

Moment tensor analysis of the acoustic emission source in the rock damage process

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Progress in Natural science:materials International 2005年第7期15卷 609-613页

作者： yu Huaizhong, ZHU Qingyong, YIN Xiangchu and WANG yucang ( State Key Laboratory of Earthquake Dynamics, Institute of Geology, china Earthquake Administration, beijing 100029, china State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of sciences, beijing 100080, china School of Mathematics and Computational science, Zhongshan university, Guangzhou 510275, china Center for Analysis and Prediction, china Seismological Bureau, beijing 100036, china Quakes, department of Earth science, university of Queensland, Brishbane, Austrialia) State Key Laboratory of Earthquake Dynamics Institute of Geology China Earthquake Administration Beijing 100029 China. State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China. School of Mathematics and Computational science Zhongshan University Guangzhou 510275 China. Center for Analysis and Prediction China Seismological Bureau Beijing 100036 China. Quakes Department of Earth Science University of Queensland Brishbane Austrialia

To further investigate the mechanism of acoustic emission (AE) in the rock fracture experiment, moment tensor analysis was carried out. The AE sources characterized by crack sizes, orientations and fracture modes, are represented by a time-dependent moment tensor. Since the waveforms recorded by AE monitors correlate to the moment tensors, we prefer to select the P wave amplitude from the full-space Green's function of homogeneous and isotropic materials to determine the six independent components of the moment tensor. The moment tensor analysis was used to investigate the AE sources recorded in the experiment, and three types of micro-cracks were found, which are tensile mode, shear mode and mixture of the tensile and shear mode. In addition, the motion of micro-cracks was decided by eigenvectors of moment tensor. Results indicate that the moment tensor analysis may be used as a measurement to reflect the damage evolution of rock specimen.

关键词： moment tensor acoustic emission rock fracture.

Design,fabrication and experimental research for an electrohydrodynamic micropump

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science china(Technological sciences) 2010年第10期53卷 2839-2845页

作者： yu He, yu Jian & MA ChongFang Key Lab of Enhanced Heat Transfer & Energy Conservation, Ministry of Education and Key Lab of Heat Transfer & Energy Conversion, beijing Municipality, College of Enviromental and Energy Engineering, beijing university of technology, beijing 100124, china 1. Key Lab of Enhanced Heat Transfer & Energy Conservation Ministry of Education and Key Lab of Heat Transfer & Energy Conversion Beijing Municipality College of Enviromental and Energy Engineering Beijing University of Technology Beijing 100124 China

This paper presented a novel electrohydrodynamic (EHD) micropump based on MEMS technology. The working mechanisms and classification of EHD micropump were introduced. The fabrication process of EHD micropump was presented with the material selection,optimal design of microelectrode and assembly process. Static pressure experiments and flow experiments were carried out using different fluid and the channel depth. The results indicated that the micropump could achieve a maximum static pressure head of 268 Pa at an applied voltage of 90 V. The maximum flow rate of the micropump-driven fluid could reach 106 μL/min. This paper analyzed the future of combining micropump with heat pipe to deal with heat dissipation of high power electronic chips. The maximum heat dissipation capacity of 87 W/cm2 can be realized by vaporizing the micropump-driven liquid on vaporizing section of the heat pipe.

关键词： electrohydrodynamic (EHD) MEMS micropump electronic cooling

Molecular dynamics simulation of kink in 〈100〉 edge dislocation in body centred cubic iron

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Chinese science Bulletin 2007年第16期52卷 2291-2296页

作者： CHEN LiQun1,2,WANG Chongyu2,3,4 & yu Tao2 1 College of sciences,Central South university of Forestry & technology,Changsha 410004,china 2 Central Iron and Steel Research Institute,beijing 100081,china 3 department of physics,Tsinghua university,beijing 100084,china 4 International Center for materials physics,Chinese Academy of sciences,Shenyang 110016,china College of sciences Central South University of Forestry and Technology Changsha 410004 China

Using the molecular dynamics method,we have constructed two kink models corresponding to the 〈100〉{010} and 〈100〉{011} edge dislocations (EDs) in body centred cubic (bcc) Fe. It is found that the geometric structure of a kink depends on the type of edge dislocation and the structural energies of the atoms sites in the dislocation core region. The formation energies,migration energies and widths of the kinks in different types of EDs are calculated. The results show that formation and migration of the kink in the 〈100〉{010} edge dislocation are difficult. The 〈100〉{011} edge dislocation moves primarily through kink nucleation,rather than kink migration.

关键词：分子动力学边缘位移铁纽结结构

Effect of heat treatment on the transformation behavior and temperature memory effect in TiNiCu wires

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Rare Metals 2009年第1期28卷 63-67页

作者： yu Huajun XIANG Xia department of Applied physics University of Electronic Science and Technology of China Chengdu 610054 China

The effect of heat treatment on the phase transformation behavior of TiNiCu shape memory alloy wires and the temperature memory effect in this alloy were investigated by the resistance method. These results showed that with increasing annealing temperature and annealing time, the phase transformation temperatures of TiNiCu wires were shifted to higher temperatures in the heating and cooling process. It was also found that incomplete thermal cycles, upon heating the TiNiCu wires, which were arrested at a temperature between the start and finish temperatures of the reverse martensite transformation, could induce a kinetic stop in the next complete thermal cycle. The kinetic stop temperature was closely related to the previous arrested temperature. This phenomenon was defined as the temperature memory effect. The result of this study was consistent with the previous report on the phenomenon obtained using the differential scanning calorimetry method, indicating that temperature memory effect was a common phenomenon in shape memory alloys.

关键词： TiNiCu shape memory alloy heat treatment phase transformation temperature temperature memory effect