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A low frequency piezoelectric power harvester using a spiral-shaped bimorph

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Science china(Physics,Mechanics & Astronomy) 2006年第6期49卷 649-659页

作者： HU Yuantai1,2,HU Hongping2 & YANG Jiashi3.1. Institute of Mechanics and Sensing Technology,central south university,Changsha 410083.{3. 2. Department of Mechanics,Huazhong university of Science and Technology,wuhan 43.074,{3. 3. Department of Engineering Mechanics,university of Nebraska,Lincoln,NE 68588-0526,USA 1. Institute of Mechanics and Sensing Technology Central South University Changsha 410083 China 2. Department of Mechanics Huazhong University of Science and Technology Wuhan 430074 China 3. Department of Engineering Mechanics University of Nebraska Lincoln NE 68588-0526 USA

We propose a spiral-shaped piezoelectric bimorph power harvester operating with coupled flexural and extensional vibration modes for applications to low frequency energy sources. A theoretical analysis is performed and the computational results show that the spiral structure has relatively low operating frequency compared to beam power harvesters of the same size. It is found that to optimize the performance of a piezoelectric spiral-shaped harvester careful design is needed.

关键词： spiral-shaped bimorph,piezoelectric harvester,power density.

A novel framework of multi-channel acoustic echo cancellation

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Progress in Natural Science:Materials International 2006年第9期16卷 983-987页

作者： HE Zhaoshui, XIE Shengli and FU Yuli (school of Electronics & information Engineering, south{3. university of Technology, Guangzhou 510640,{3.) [a]school of Electronics & information Engineering South China University Guangzhou China

Conventionally, multi-channel acoustic echo cancellation (AEC) achieves the goal by estimating the impulse responses of the local room. However, generally, conventional AEC methods have no unique solutions. Due to the strong correlation of the input signals, conventional methods are with many disadvantages. To overcome this problem, a new framework is proposed in this paper based on SIMO (single input multiple output) blind deconvolution. Under the new framework, we achieve the goal by identifying the impulse responses of distant room and avoiding the disadvantages of the conventional methods.

关键词： SIMO blind deconvolution multi-channel acoustic echo cancellation impulse response.

Finite Element Analysis of Die Geometry and Process Conditions Effects on Equal Channel Angular Extrusion for β-Titanium Alloy

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Journal of Iron and Steel Research International 2012年第10期19卷 54-58页

作者： SI Jia-yong1,2, GAO Fan3. ZHANG Ji3.(1. State Key Laboratory of Powder Metallurgy, central south university, Changsha 410083. Hunan,{3. 2. College of Mechanical and Electrical Engineering, central south university of Forestry and Technology, Changsha 410004, Hunan,{3. 3. High Temperature Material Research Division, central Iron and Steel Research Institute, Beijing 100081,{3.) [a] State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 Hunan China [b] College of Mechanical and Electrical Engineering Central South University of Forestry and Technology Changsha 410004 Hunan China [c] High Temperature Material Research Division Central Iron and Steel Research Institute Beijing 100081 China

The finite element analysis was applied to evaluate the respective influences of die geometry and process conditions on plastic strain distribution for β-titanium (Ti-13.11Cr3.l) alloy during the equal channel angular extrusion (ECAE). It was found that optimum equal channel angular extrusion die geometry is strongly material dependent. Optimal strain homogeneity in the Ti-13.11Cr3.l alloy may be achieved at r (inner radius)=5 mm, R (outer radius)=3.mm. The equivalent plastic strain increases with increasing friction coefficient. And the better homogeneity of the equivalent plastic strain distribution can be achieved when friction coefficient value is lower. The faster the ram speed is, the lower the homogeneity of the equivalent plastic strain distribution is and the influence is slight. The back-pressure does not help to improve the plastic strain homogeneity, and the increasing temperature has a slightly favourable effect on the plastic strain homogeneity between 400 and 600 ℃.

关键词： equal channel angular extrusion finite element analysis die geometry β-titanium

Blind signal separation of underdetermined mixtures based on clustering algorithms on planes

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Progress in Natural Science:Materials International 2007年第6期17卷 670-674页

作者： Xie Shengli, Tan Beihai and Fu Yuli(school of Electronics & information Engineering, south{3. university of Technology, Guangzhou 510640,{3.) [a]school of Electronics & information Engineering South China University of Technology Guangzhou China

Based on clustering method on planes, blind signal separation (BSS) of underdetermined mixtures with three observed signals is discussed. The condition of sufficient sparsity of the source signals is not necessary when clustering method on planes is used. In other words, it needs not that only one source signal plays the main role among others at one time. The proposed method uses normal line clustering of planes first. Then, the mixing matrix can be identified via deciding the intersection lines of the planes. This method is an effective implement of the new theory presented by Georgiev. Simulations illustrate accuracy and restoring capability of the method to estimate the mixing matrix.

关键词： underdetermined mixture sparse representation mixing matrix blind signal separation.

Determination of the Thermal Expansion Coefficient of Concrete at Early Ages by Using Temperature-stress Testing Machine

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Journal of wuhan university of Technology(Materials Science) 2006年第4期21卷 146-149页

作者：霍凯成 Hubei Key Laboratory of Roadway Bridge & Structure Engineering Wuhan University of TechnologyWuhan 430070China

By using the uptodate temperatuer-stress testing machine, the thermal expansion coefficient of concrete at early ages was studied and indicative conclusions were achieved ： temperature rising due to hydration heat is not directly correlated with cracking, but the temperature and stress evolation process should be taken into consideration in the same time. Proper chemical admixtures and mineral cornpasitions can improve the mechanical properties of concrete such as thermal expansion coefficient, which is very indicative in practice.

关键词： concrete coefficient of thermal expansion temperature-stress test

Mass Concentration of Particles (PM10) in Urban Environment of Changsha,china

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湖南大学学报（自然科学版） 2009年第S1期36卷 5-9页

作者： TANG Meng,DENG Qi-hong,WANG Qi(school of Energy Science & Engineering,central south {3.,Changsha,Hunan 410083.china) school of Energy Science and Engineering Central South University Changsha 410083 China

Continuous measurement of ambient PM10 was performed by TEOM at a university campus for about one year from 20 November 2007 to 29 October 2008 in Changsha city of Hunan *** PM10 and PM2.5 concentration were measured by DustTrak simultaneously in order to describe the difference in concentration level and daily variations of particle mass concentration between different seasons,and to survey the influence of ambient particle on indoor air *** the survey period,the annual average PM10 concentration was found to be 117.63.μg/m3.with a mean value 121.88 μg/m3.in winter and 111.50 μg/m3.in *** temporal trend changed quickly from time to time,and the peak values were found in rush hours and in the *** PM10 showed a good correlation with indoor PM10 and outdoor PM2.5 but not with indoor *** results showed that PM10 was influenced by local source(such as traffic or fuel burning)and regional *** correlation analysis has shown that ambient PM10 contributes substantial fraction to indoor PM10 but not to indoor PM2.5,which indicates other source may exist in the indoor environment.

关键词： particle mass concentration human activity relationship

Polycomb group proteins and their roles in carcinogenesis

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Chinese Science Bulletin 2012年第18期57卷 2259-2264页

作者： XIAO LanBo 1,2,3.TAO YongGuang 1,2,3.LI LiLi 1,2,3.4 & CAO Ya 1,2,3. Key Laboratory of Carcinogenesis of Ministry of Health,Xiangya school of Medicine,central south {3.,Changsha 410078,china 2 Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education,Xiangya school of Medicine,central south {3.,Changsha 410078,china 3.Cancer Research Institute,Xiangya school of Medicine,central south {3.,Changsha 410078,china 4 Cancer Epigenetics Laboratory,State Key Laboratory in Oncology in south china,Chinese {3. of Hong Kong,Hong Kong 999077,china Key Laboratory of Carcinogenesis of Ministry of Health Xiangya School of Medicine Central South University Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education Xiangya School of Medicine Central South University Cancer Resea

In the cell nucleus,DNA is wound around histone proteins,which are then packed together to form *** can be chemically tagged by methyl and acetyl *** group (PcG) proteins attach methyl groups to genes,which block their *** is similar to the attachment of methyl groups to gene promoters by DNA methyltransferases (DNMTs).This action is directly linked with tumor initiation and metastasis via the promotion of anti-senescence and anti-apoptosis pathways,and by facilitating epithelial mesenchymal transition (EMT).Cell fate transcriptional factors (CFTFs) and long non-coding RNAs (long ncRNAs) recruit PcG proteins to the promoters of tumor suppressor genes,resulting in epigenetic gene silencing by influencing chromatin structure and DNA ***,PcG proteins are potential diagnostic markers and targets for new chemoprevention and therapeutic strategies.

关键词：组蛋白 DNA甲基转移酶基因启动子癌变非编码RNA PEG 凋亡途径抑癌基因

Determination of phase equilibria in the Ni-Ta-Zr system at 1223.K

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Rare Metals 2003年第3期22卷 160-163页

作者： PAN Ximiao and JIN ZhanpengPhase Diagram and Materials Design Center, school of Materials Science and Engineering, central south {3., Changsha 410083. china Phase Diagram and Materials Design Center School of Materials Science and Engineering Central South University Changsha 410083

The phase equilibrium relations of the ternary Ni-Ta-Zr system at 1223.K wereinvestigated by means of diffusion triple and electron probe microanalysis (EPMA) techniques. Twoternary compounds were found and a series of tie lines and tie triangles have been determined. Themaximum solubility of Ta in NiZr_2 is about 13.5% (atom fraction). The corresponding tentativeisothermal section at this temperature was constructed based on current experimental information.

关键词： phase diagram diffusion triple nickel EPMA Ni-Ta-Zr system

A new approach toward object-based change detection

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Science china(Technological Sciences) 2010年第S1期53卷 105-110页

作者： ZHANG Guo1,2,LI Yang1 & LI ZhiJiang3.1 State Key Laboratory of information Engineering in Surveying,Mapping and Remote Sensing,wuhan university,wuhan 43.079,china 2 Satellite of Surveying and Mapping Application center,State Bureau of Surveying and Mapping,Beijing 10083.,china 3.school of Printing and Packaging,wuhan university,wuhan 43.079,china wuhan Univ State Key Lab Informat Engn Surveying Mapping & R Wuhan 430079 Peoples R China State Bur Surveying & Mapping Satellite Surveying & Mapping Applicat Ctr Beijing 100830 Peoples R China wuhan Univ Sch Printing & Packaging Wuhan 430079 Peoples R China

Object-based change detection has been the hotspot in remote sensing image processing.A new approach toward object-based change detection is *** two different temporal images are unitedly segmented using the mean shift procedure to obtain corresponding *** change detection is implemented based on the integration of corresponding objects’ intensity and texture *** are conducted on both panchromatic images and multispectral images and the results show that the integrated measure is robust with respect to illumination changes and *** color detection is conducted to determine whether the color of the unchanged objects changes or not when dealing with multispectral *** verification work is carried out to show the accuracy of the proposed approach.

关键词： mean shift united segmentation change detection object-based intensity texture integration