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An introduction to Tsinghua Cloud

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science china(Information sciences) 2010年第7期53卷 1481-1486页

作者： ZHENG WeiMin1,2.1department of Computer science and{2., Tsinghua University, {3. 100084, china 2.singhua National Laboratory for Information science and{2., {3. 100084, china 1. department of Computer science and{2. Tsinghua University Beijing 100084 China2. Tsinghua National Laboratory for Information Science and Technology Beijing 100084 China

Cloud computing has become a trend that draws attention from both academia and industry all over the world. This paper unveils details of Tsinghua Cloud, a comprehensive solution for cloud computing developed by Tsing... 详细信息

关键词： cloud computing distributed file system virtual computing environment data sharing

Effect of Post-spinning Modification on the PAN Precursors and Resulting Carbon Fibers

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Journal of Wuhan University of technology(Materials science) 2006年第3期21卷 44-48页

作者：张旺玺 department of Mechanics Engineering Zhongyuan Institute of TechnologyZhengzhou 450070China

The impregnation of a special grade PAN precursor,fibers wus carried out in a 8 wt% KMnO4 aqueous solution to obtain modified PAN precursor fibers. The effects of modification on the chemical stncture and the mechanical properties of precursor fibers thermally stabilized and their resulting carbon fibers u＇ere characterized by the combiination use of densities, wide-angle X-ray diffraction （WAXD）, X-ray photoelectron speetroscopy （XPS）, elemental analysis （ EA ）, Fourier traasform infrared spectroscopy （FT-IR） and scanning electron microscope （SEM）, ***4 as a strong oxidizer can swell, oxidize and corrode the skin of a ***, and transform C≡N groups to C≡N ones, meamchile , it can decreuse the crystal .size increuse the orientation index and the costallinity index, furthermore it can increuse the densities of modified PAN precursors and resuhing thermally stabilized fibers. As a result, the carbon fibers developed from modified PAN fibers show an improvement in tensile strength of 3..2. % and an improvement in elongation of 77.78 % , but a decrease of 16. 52. in Young＇s modulus.

关键词： carbon fibers carbon precursor chemical treatment mechanical properties

On the construction of multi-output Boolean functions with optimal algebraic immunity

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science china(Information sciences) 2012年第7期55卷 1617-1623页

作者： ZHANG Jie 1,2.,SONG ShouChao 1 ,DU Jiao 2.3.& WEN QiaoYan 2.1 School of science,{2. University of Posts and Telecommunications,{2. 100876,{3. 2.State Key Laboratory of Networking and Switching technology,{2. University of Posts and Telecommunications,{2. 100876,{3. 3.department of Mathematics,Xinxiang University,Xinxiang 453.03.{3. 1. School of science Beijing University of Posts and Telecommunications Beijing 100876 China2. State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China3. Department of Mathematics Xinxiang University Xinxiang 453003 China

In this paper,we show a construction of multi-output Boolean functions with optimal algebraic ***,the relationship between the algebraic immunity of a multi-output Boolean function and those of its component functions is *** show that all the component functions,together with their nonzero linear combination,of the multi-output Boolean functions achieved by this construction have optimal algebraic immunity simultaneously.

关键词： algebraic immunity Boolean functions algebraic attacks annihilators

Synthesis and thermodynamic analysis of nano-La2.3

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Progress in Natural science:Materials International 2007年第7期17卷 838-844页

作者： Liu Lili~(1,2. Tang Jie~2.Li Yuxiang~1 Zhang Mei~(1**) Wang Xidong~(1,3. (1.department of Physical Chemistry,University of {2. and {2. {3.,{3. 100083.china 2.National Institute for Materials {2.,Segen 1-2.1,Tsukuba 3.5-0047,Japan 3.College of Engineering,{3. University,{3. 100871,china) [a]department of Physical Chemistry University of Science and Technology Beijing Beijing China [b]National Institute Materials science Tsukuba Jpan [c]College of Engineering Beijing University Beijing China

The thermodynamic parameters of La（NO3.3.nd La（OH）3.re evaluated and the thermodynamics of nano-La2.3.yn- thetic process is *** the base of thermodynamic analysis,La2.3.ano-powders are prepared by the sol-gel method and the experi- ment scheme is designed by an orthogonal *** dry-gelatin is analyzed with differential thermal analysis/thermo-gravimetric analy- sis（TGA-DTA）and X-ray diffraction *** microstructure of nano-La2.3.owders is observed by transmission dectron micro- *** synthetic parameters affecting the average grain size and dispersivity of nano-La2.3.articles are experimentally examined and *** the results indicate that nano-La2.3.articles well-dispersed are obtained and the average grain size is in the range of 2.—50 nm.

关键词： nano-La2.3 sol-gel thermodynamic analysis

EFFECT OF Cr ADDITION ON MICROSTRVCTURES AND MECHANICAL PROPERLIES OF β-NiAl ALLOYS

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Acta Metallurgica Sinica(English Letters) 1999年第2期12卷 173-180页

作者： W.H. Tian S.L. Hu and M. Nemoto(1) department of Materials Physics, University of science and{2. {3., {3. 100083. china 2. department of Materials Forming, University of science and{2. {3., {3. 100083. china 3. department Univ of science and technology Beijing Beijing China

The effect of Cr addition on the microstructures and mechanical properties of NiAl inermetallic alloys containing 4 to 8 mol% Cr has been characterized. It is shown that Cr is not only an efficient soild solution strengthener in NiAl, it is also an efficient precipitation Strengthener by fine dispersion of α-Cr particles. Transmission electron microscope observations have revealed that fine spherical particles of α-Cr appeared homogeneously in the NiAl matrix by aging at temperatures around 1073. after solution annealing at 1563.. The aging behavior was investigated by microhardness measurements and the temperature dependence of the yield stress of NiAl containing α-Cr particles was investigated by compression tests over the tempemture range from 2.8 to 1173.. NiAl alloys happened appreciably by the precipitation of α-Cr *** bypass the particles during deformation and typical Orowan loops were observed surrounding the α-Cr particles after deformation. Although the dispersion Of α-Cr particles increases the yield strength of NiAl at intermediate temperutre, the strength decreases appreciably at higher temperatures.

关键词： NiAl age-hardening precipitate deformation mechanism microstructure

A user-space file system for on-demand legacy desktop software

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science china(Information sciences) 2011年第6期54卷 1142-1150页

作者： ZHANG YouHui 1,2., SU GeLin 1,2.& ZHENG WeiMin 1,2.1 department of Computer science and{2., Tsinghua University, {3. 100084, china 2.Tsinghua National Laboratory for Information science and{2., Tsinghua University, {3. 100084, china 1. department of Computer science and{2. Tsinghua University Beijing 100084 China2. Tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing 100084 China

Some user-level virtualization technologies have been used to convert legacy software (like the existing Windows desktop applications) into the on-demand software without any modification. To give the client a friendly and compatible method to access on-demand legacy software across the Internet, this paper presents a clientend file system for this usage case. It is a Windows user-space file system based on the cloud storage (where the on-demand software is stored), which converts the local file system accesses into remote visits. Quite a few optimizations are adopted and adjusted to suit the file-access-pattern of on-demand software, including the local cache, metadata/data/software prefetch and content-addressable storage (CAS), to decrease the number of remote visits and/or to overlap IO (input/output) operations with software execution. Detailed access-pattern analyses are also presented. This file system has been implemented and tests show that it is practical for much daily-used software-a local cache of limited size can provide up to 80% hit ratio and the corresponding overhead of running-time is about 3.%. Owing to this method, on any compatible and networked computer, a user can use his/her personalized software conveniently although it does not exist on the local host.

关键词： on-demand software software as a service user-space file system cloud storage

Electric-stimulus rate encoding algorithm of Mandarin tonal information in cochlear implant

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Progress in Natural science:Materials International 2006年第12期16卷 1315-1321页

作者： GUAN Tian~1, GONG Qin~1 and YE Datian~2.*(1. department of Biomedical Engineering, Tsinghua University, beijing 100084,{2. 2. Research {3. of Biomedical Engineering, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055,{2.) [a]department of Biomedical Engineering Tsinghua University Beijing China [b]Research center of Biomedical Engineering Graduate School at Shenzhen Tsinghua University Shenzhen China

The modern multi-channel cochlear implants usually extract and encode the temporal envelope cues. This kind of algorithms can hardly satisfy the users who speak tonal languages, such as Mandarin. Many studies have tried to enhance the recognition ability of Mandarin through encoding tonal information and made suggestions to frequency-modulate the fixed pulse-rate carrier with the extracted tonal information based on the rate-pitch theory in electric hearing. However, how to encode and deliver the tonal information such as F_0by changing electric-stimulus rate has not got further study in clinical electric-stimulus mode. The present paper focuses on this matter by piecewise calculating the appreciable electric-stimulus rates. Then an electric-stimulus encoding algorithm of Mandarin tone is brought forward and testified through acoustic simulations. Such conclusion can be drawn that this algorithm of electric-stimulus rate could convey tonal information well and help to enhance the Mandarin speech recognition ability.

关键词： cochlear implant tone fundamental frequency electric-stimulus rate.

Existence of solutions for the dynamic equation of ferrimagnets

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Progress in Natural science:Materials International 2007年第11期17卷 1279-1283页

作者： Zeng Ming1, Guo Boling2.and Cheng Caozong1(1. College of Applied sciences, beijing University of{2.,{3., china 2. center for Nonlinear Studies, Institute of Applied Physics and Computational Mathematics, beijing 100088, china) College of Applied sciences Beijing University of Technology Beijing 100022 China center for Nonlinear Studies Institute of Applied Physics and Computational Mathematics Beijing 100088 China

Ferrimagnet is a kind of basic and important multi-sublattice magnet material. It has attracted more and more attention of physicists and mathematicians. Many results of solitons and numerical computations on this topic have appeared. In this article, the dynamic equation for an isotropic ferrimagnet with two non-equivalent sublattices is studied, existence of weak solutions in multi dimension case is proved through the penalized method, the uniqueness and smoothness of the solution in one dimension case are also obtained by the relation between this equation and hyperbolic equation.

关键词： ferrimagnet weak solutions penalized method finite difference method

Subchronic toxicological effects of aquatic nitrobenzene on Medaka and Chinese rare minnow

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science china Chemistry 2007年第5期50卷 707-717页

作者： ZHOU QunFang1, FU JianJie1,2. MENG HaiZhen1,2. ZHU XueYan1,2. JIANG GuiBin1, ZHANG JianBin1, LIU JieMin2.& SHI GuoQing2.1 State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research center for Eco-environmental sciences, Chinese Academy of sciences, {3. 100085, china 2.department of Chemistry, School of Applied science, University of science and technology {3., {3. 100083. china State Key Laboratory of Environmental Chemistry and Ecotoxicology ResearchCenter for Eco-environmental SciencesChinese Academy of SciencesBeijing 100085China department ofChemistry School of Applied ScienceUniversity of Science and Technology B

Based on the simulative exposure experiments of nitrobenzene to two small experimental fishes, Medaka (Oryzias latipes) and Chinese Rare Minnow (Gobiocypris rarus), it was found that nitrobenzene could decrease in a linear way in the static aquatic system. Both fishes could accumulate dose-related levels of nitrobenzene quickly and eliminate the compound rapidly when they were transferred to clean water. The Chinese rare minnow showed more sensitivity to the acute toxicity exposure of nitrobenzene than Medaka. Typical molecular biomarkers in oxidative defense system including superoxide dismu- tase (SOD), catalase (CAT) showed the chemical induced alterations. The changes of acetylcholi- nesterase (AChE) activities indicated that nitrobenzene might affect the normal neural function. Nitro- benzene exposure could also lead to obvious damaging effects on the target organs, such as gill and liver by hitopathological studies.

关键词： nitrobenzene, Medaka, Chinese rare minnow, bioaccumulation, elimination, molecular biomarkers, histopathological effects