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Preparation of water-soluble multi-walled carbon nanotubes by Ce(IV)-induced redox radical polymerization

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Progress in Natural Science:Materials International 2009年第8期19卷 991-996页

作者： Dong Yang, Xiaohong Zhang, changchun Wang, Yuechao Tang, Junjun Li, Jianhua Hu key laboratory of Molecular {3. of Polymers (ministry of education) and Department of Macromolecular Science, Fudan university, Shanghai 20043., china [a]key laboratory of Molecular engineering of Polymers ({3.istry of education) and Department of Macromolecular Science Fudan University Shanghai 200433 China

Poly(acrylic acid), poly(N-isopropylacrylamide) and polyacrylamide functionalized MWNTs were prepared by Ce(IV)-induced redox radical polymerization. The reaction can be conducted in aqueous media at room temperature, and the polymer graft ratio increased with the increase of monomer feed ratio. MWNTs anchored with PAA on the surface are pH sensitive and exhibit a reversible assembly–deassembly response in aqueous solution, whereas those coated with PNIPAM are thermally sensitive. All the polymer-functionalized MWNTs are highly soluble in water to give robust stable black solutions. Such water-soluble MWNTs are promising for biological and biomedical applications.

关键词： Carbon nanotube Redox polymerization Water solubility Stimuli response

Expression,Purification and Crystal Structure of a Truncated Acylpeptide Hydrolase from Aeropyrum pernix K1

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Acta Biochimica et Biophysica Sinica 2005年第9期37卷 613-617页

作者： Hai-Feng ZHANG Bai-Song ZHENG~1 Ying PENG Zhi-Yong LOU Yan FENG~* Zi-He RAO~* laboratory of Structural Biology,Department of Biological Sciences and Biotechnology and Protein Sciences laboratory of min{3. of education,Tsinghua university,Beijing 100084,china 1 key laboratory for Molecular Enzymology and engineering of min{3. of education,{13. university,changchun 13.023.china laboratoryofStructuralBiology DepartmentofBiologicalSciencesandBiotechnologyandProteinSciencesLaboratoryofM

Acylpeptide hydrolase （APH） catalyzes the N-terminal hydrolysis of Nα-acylpeptides to releaseNα-acylated amino acids. The crystal structure of recombinant APH from the thermophilic archaeon Aeropyrumpernix K1 （apAPH） was reported recently to be at a resolution of 2.1 （?） using X-ray diffraction.A truncatedmutant of apAPH that lacks the first short α-helix at the N-terminal,apAPH-△（1-21）,was cloned,expressed,characterized and *** from biochemical experiments indicate that the optimum temperature ofapAPH is decreased by 15℃ with the deletion of the N-terminal α-***,the enzyme activity at theoptimal temperature does not *** suggests that this N-terminal α-helix is essential for ***,the crystal structure of apAPH-△（1-21） has been determined by molecular replacement to 2.5 （?）. Acomparison between the two structures suggests a difference in thermostability,and it can be concluded thatby adding or deleting a linking structure （located over different domains）,the stability or even the activity ofan enzyme can be modified.

关键词： acylpeptide hydrolase Aeropyrum pernix K1 crystal structure

Interface of 3. Micro-cellular Structural AlMnCe/Al_2O_3.Composite

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稀有金属材料与工程 2011年第S3期40卷 128-131页

作者： Wang Shuxia, Li Shaolong, Jiang Qiuyue, Shi Lei, Wang minggang, Jia Suqiu, Zhao Zhankui key laboratory of Advanced Structural Materials, ministry of education, changchun university of Technology, changchun 13.012, china changchun Univ Technol Key Lab Adv Struct Mat Minist Educ Changchun 130012 Peoples R China

The AlMnCe/Al2O3.metal/ceramic composite with 3. micro-cellular structure is prepared by spark plasma sintering (SPS) at 520 ℃. It consists of consecutive nano-Al2O3.sintering body phase and AlMnCe alloy discrete phase. The microstructure of sample, characteristic of the micro-cellular structure and microstructure of the interface are investigated via scanning electron microscope (SEM) and transmission electron microscope (TEM) method. The results indicate that two kinds of interfaces are formed in the sample during SPS process, one is the micro-nano type metal/ceramic interface between the metal cellular body and the nano-ceramic cellular wall, the other is the nano-nano type ceramic/ceramic interface in the nano-ceramic cellular wall. The fusion transition area with a width 200-3.0 nm at interface of the AlMnCe alloy and nano-Al2O3.sintering body is formed. The AlMnCe alloy has a sufficient immersional wetting for the Al2O3.cellular wall. The bonding of interface between the nano-Al2O3.sintering body and the AlMnCe alloy particle is powerful, and new phase and crack is not found.

关键词： spark plasma sintering composite microcellular structure interface

A New Markov Model Used for Path Prediction Over WLAN

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A New Markov Model Used for Path Prediction Over WLAN

On an attack on RSA with small CRT-exponents

第一届工程科学与力学中的计算方法国际会议

作者： Xuegang Yu Yanheng Liu Da Wei ming Tian and Pin Wang College of Computer Science and Technology jilin university {3. china key laboratory of Symbolic computation and knowledge engineering of ministry of education jilin university {3. china Department of Mathematics Ocean university of china Qingdao china

＜正＞In order to reduce the complexity of the state space in Order-k Markov predictor, a new Step-2 Markov predictor is proposed to make path prediction over WLAN. The Step-2 Markov Predictor’s feasibility is proved by calculating and comparing conditional entropy of Step-2 and Order-k Markov predictors. And the paper also analyzes and compares the prediction accuracy of the two kinds of Markov Predictors using actual Wi-Fi trace data. The work shows that the Step-2 Markov predictor is more stable than Order-1 Markov Predictor for different length trace files and it also reduces the complexity of the Markov state space dramatically and gets approximately the same prediction accuracy with Order-2 Markov predictor and higher accuracy than Order-others Markov predictors.

关键词： path prediction order-k Markov model step-k Markov model

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Science china(Information Sciences) 2010年第8期53卷 1511-1518页

作者： HAN LiDong 1,2 , WANG XiaoYun 3.& XU GuangWu 3.4 1 key laboratory of Cryptologic Technology and Information Security, min{3. of education, Shandong university, Jinan 250100, china 2 School of Mathematics, Shandong university, Jinan 250100, china 3.Institute for Advanced Study, Tsinghua university, Beijing 100084, china 4 Department of Electrical engineering and Computer Science, university of Wisconsin-Milwaukee, Milwaukee, WI 53.01, USA 1. key laboratory of Cryptologic Technology and Information Security Ministry of Education Shandong University Jinan 250100 China2. School of Mathematics Shandong University Jinan 250100 China3. Institute for Advanced Study Tsinghua University Beijing 100084 China4. Department of Electrical Engineering and Computer Science University of Wisconsin-Milwaukee Milwaukee WI 53201 USA

This paper concerns the RSA system with private CRT-exponents. Since Chinese remainder representation provides efficiency in computation, such system is of some practical significance. In this paper, an existing attack to small private CRT-exponents is analyzed. It is indicated that this attack makes nice use of lattice in RSA analysis, but some argument does not hold in general. Several counterexamples are constructed. Refinements and more precise statements of the attack are given.

关键词： RSA CRT cryptanalysis continued fraction lattice reduction

AN EFFICIENT MOVING MESH METHOD FOR A MODEL OF TURBULENT FLOW IN CIRCULAR TUBES

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Journal of computational Mathematics 2009年第Z1期 388-399页

作者： Yin Yang Hunan key laboratory for computation and Simulation in Science and {3.,School of Mathematics and computational Science,Xiangtan university,Xiangtan 411105,china Yanping Chen School of Mathematical Sciences,South china Normal university,Guangzhou,china Yunqing Huang Hunan key laboratory for computation and Simulation in Science and {3.,School of Mathematics and computational Science,Xiangtan university,Xiangtan 411105,china

This paper presents an efficient moving mesh method to solve a nonlinear singularproblem with an optimal control constrained *** physical problem is governedby a new model of turbulent flow in circular tubes proposed by Luo et *** Prandtl’smixing-length *** algorithm is formed by an outer iterative algorithm for handlingthe optimal control condition and an inner adaptive mesh redistribution algorithm forsolving the singular governing *** discretize the nonlinear problem by using aupwinding approach,and the resulting nonlinear equations are solved by using the Newton-Raphson *** mesh is generated and the grid points are moved by using thearc-length equidistribution *** numerical results demonstrate that proposedalgorithm is effective in capturing the boundary layers associated with the turbulent model.

关键词： Eddy viscosity Turbulent pipe flow Boundary layer Optimal control Moving mesh

Chemoenzymatic Synthesis of Ramosetron Hydrochloride

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Chemical Research in Chinese Universities 2012年第1期28卷 70-72页

作者： LIU Qing-wen1 , XU Hao1, TIAN Hua1, ZHENG Liang-yu2 and ZHANG Suo-qin1 1. College of Chemistry, 2. key laboratory for Molecular Enzymology and {3., ministry of education, jilin university, changchun 13.012, P. R. china jilin Univ Minist Educ Key Lab Mol Enzymol & Engn Changchun 130012 Peoples R China jilin Univ Minist Educ Coll Chem Changchun 130012 Peoples R China

A new method for the synthesis of ramosetron hydrochloride, the most wildly used 5-HT3.receptor antagonist, was reported. The intermediate 8 was obtained in a high e.e. value via lipase catalyzed hydrolytic kinetic resolution. Then enantiomerically pure ramosetron hydrochloride was synthesized in two steps with excellent yield （the total yield is 24.6%）. The method provides a new environment friendly and atom economy way to synthesize enantiomerically pure ramosetron.

关键词： Ramosetron hydrochloride Chemical enzymatic synthesis Atom economy

Image Segmentation by Aggregation Graph-Cuts

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Image Segmentation by Aggregation Graph-Cuts

Microstructure and Performances of Nanocrystalline Zinc-nickel Alloy Coatings

The 12th International Multimedia Modelling Conference(MMM2006)

作者： Dongfeng Han Wenhui Li Tianzhu Wang WangYi And Yanjie She College of Computer Science and Technology,key laboratory of Symbol computation and {3. engineering of the ministry of education,jilin university,changchun,13.012,P.R.china

In this paper,we describe a fast semi-automatic segmentation algorithm using nodes aggregation and *** segmentation process is reliably computed automatically no additional users’ efforts are *** is convenient and ef...

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材料热处理学报 2004年第5B期25卷 1275-1278页

作者： LIGuang-yu LIANJian-she NIULi-yuan JIANGZhong-hao ThekeyLabofAutomobileMaterials MinistryofEducation.ChinaCollegeofMaterialsSc＇ienceandEngineeringJilinUniversityNantingCampusChangchun130025.China

Nanocrystalline zinc-nickel alloy coatings were deposited from an alkaline zincate bath contained an organic additive that can reduce polarization and a complexing agent. SEM and TEM observations and XRD analysis were performed to examine the microstructure and phase composition of the coatings. The nickel content in deposits is 12.0-14.7% and the coating is consisted of single nanocrystalline y-phase structure (Ni5Zn2i), with grain average grain size about 15nm. The nanocrystalline zinc-nickel alloy coatings have better corrosion resistance, less bnttleness and higher microhardness than the conventional zinc coatings.

关键词：显微结构纳米结晶锌镍合金 SEM TEM