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Characterization of In-situ Titanium Matrix Composites Prepared by Laser Melting Deposition

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稀有金属材料与工程 2011年第S3期40卷 33-37页

作者： Zhang Yongzhong1, Sun Jingchao1, Huang Can1, Li Guowei2 1 General Research Institute for Non-ferrous Metals, Beijing 100088, china 2 nantong Entry-Exit Inspection and Quarantine Bureau, nantong 226005, china Gen Res Inst Nonferrous Met Beijing 100088 Peoples R China nantong Entry Exit Inspect & Quarantine Bur Nantong 226005 Peoples R China

Preliminary characterization of microstructure and mechanical properties of (TiB+TiC)/TC4 and TiC/Ti60 in-situ titanium matrix composites prepared by laser melting deposition is reported in this paper. The results indicate that in-situ reaction occurred during laser melting deposition of coaxially fed mixed powders from TC4 and B4C with formation of form TiB and TiC reinforcement. For TiC/Ti60 composites, there are some un-melted TiC particles and re-solidified TiC particles appeared as discontinuous chain-like morphology. Reinforcements of TiB and TiC with fraction about 25 vol% were formed with feeding 5 wt% B4C. The morphology of TiB tended to be needle-like and prismatic, while TiC appeared as granular. Small amount of un-reacted B4C with reduced size remained within the composites. A thin skull of reaction product formed around the un-reacted B4C weakened its interface bonding with the titanium alloy matrix, thus resulting in less outstanding properties of the composites. Under 600 ℃, the ultimate tensile strength of the TiCP (5wt%)/Ti60 composites was 60 MPa higher than that of Ti60 alloy, following with decreased elongation.

关键词： titanium matrix composites in-situ reaction laser melting deposition microstructure properties

The contribution of cis-regulatory elements to head-to-head gene pairs' co-expression pattern

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Science china(life sciences) 2009年第1期52卷 74-79页

作者： HAO Pei1,2,YU Yao2,3,ZHANG XiaoYan4,TU Kang2,FAN HaiWei2 & ZHONG Yang1 1 school of life sciences,Fudan university,Shanghai 200433,china 2 Bioinformatics Center,Key Lab of Systems Biology,Shanghai Institutes for Biological sciences,Chinese Academy of sciences,Shanghai 200031,china 3 Shanghai Center for Bioinformation Technology,Shanghai 200235,china 4 school of life sciences,Tongji university,Shanghai 200092,china 1. school of life sciences Fudan University Shanghai 200433 China 2. Bioinformatics Center Key Lab of Systems Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 200031 China 3. Shanghai Center for Bioinformation Technology Shanghai 200235 China 4. school of life sciences Tongji University Shanghai 200092 China

Transcription regulation is one of the most critical pipelines in biological process,in which cis-elements play the role as gene expression *** attempt to deduce the principles underlying the co-expression of "head-to-head" gene pairs by analyzing activities or behaviors of the shared cis-elements.A network component analysis was performed to estimate the impact of cis-elements on gene promoters and their activities under different *** discoveries reveal how biological system uses those regulatory elements to control the expression pattern of "head-to-head" gene pairs and the whole transcription regulation system.

关键词： transcription regulation cis-elements "head-to-head" gene pairs

The Role of Propeptide in the Refolding of Human Group IB Phospholipase A2

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Acta Biochimica et Biophysica Sinica 2004年第9期36卷 583-588页

作者： Hong-Qiang CHENG1 and Gen-Jun XU1,2*Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological sciences, Chinese Academy of sciences, Shanghai 200031, china 2College of life Science, Zhejiang university of sciences, Hangzhou 310033, china Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences College of life Science Zhejiang University of Sciences

Human group IB phospholipase A2 (IB-PLA2) and its zymogen (proIB-PLA2) were purified from E. coli. Refolding was carried out by diluting the denatured forms of both IB-PLA2 and proIB-PLA2 with renaturation buffer in which the disulfide bonds were completely reduced. The refolding yield of proIB-PLA2 was increased by about 50% over that of the mature enzyme. The refolding of IB-PLA2 usually produced aggregates under normal conditions, as determined by light scattering. In addition, the unfolding experiments showed that the mature enzyme was more stable than the proenzyme toward denaturants in the presence of DTT. Results suggested that the N-terminal sequence rather than its conformation of human proIB-PLA2 played an important role in the refolding process.

关键词： human group IB phospholipase A2 (IB-PLA2) refolding first disulfide bond propeptide

Function S-rough sets and security-authentication of hiding law

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Science in china(Series F) 2008年第7期51卷 924-935页

作者： SHI KaiQuan1,2 & ZHAO JianLi3 1 school of Mathematics and Computer sciences, Longyan university, Longyan 364000, china 2.school of Mathematics and System sciences, Shandong university, Jinan 250100, china 3 school of Mathematics Science, Liaocheng university, Liaocheng 252059, china 1. school of Mathematics and Computer sciences Longyan University Longyan 364000 China 2. school of Mathematics and System sciences Shandong University Jinan 250100 China 3. school of Mathematics Science Liaocheng University Liaocheng 252059 China

Function S-rbugh sets are defined by R-function equivalence class, which have dynamic characteristic. Function S-rough sets have dynamic characteristic, law characteristic and law-hiding characteristic. Function S-rough sets can generate f-hiding law and f-hiding law. By engrafting, crossing, and penetrating between the information security theory and function S-rough sets, the security hiding and the authentication of f-hiding law and f-hiding law are given respectively in this paper. The fusion and share between function S-rough sets and information security theory is a new research direction of the application of information law in information system.

关键词： function S-rough sets law-hiding elliptic curve the security-authentication of hiding law

pH-Dependent Stability of EGX, A Multi-functional Cellulase from Mollusca, Ampullaria crossean

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Acta Biochimica et Biophysica Sinica 2004年第9期36卷 603-608页

作者： Wen-Ying LI2, Ji WANG1, Yan-Hong LI1, Ming DING1, Gen-Jun XU1,3, Lan-Ying LIU2, and Fu-Kun ZHAO1,3* 1Key Laboratory of Proteomics, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological sciences, the Chinese Academy of sciences,Graduate school of the Chinese Academy of sciences, Shanghai 200031, china 2College of life Science, Jilin university, Changchun 130023, china College of life Science, Zhejiang university of Science and Technology, Hangzhou 310018, china Key Laboratory ofProteomics Institute of Biochemistry and Cell BiologyShanghai Institutes for Biological Sciencesthe Chinese Academy of SciencesGraduate School of the Chinese Academy of SciencesShanghai 200031China

The cellulase activity and stability of EGX, a multi-functional cellulase previously purified from the mollusca Ampullaria crossean, was systematically studied under different pH. The pH induced con- formation and stability change of EGX have been investigated by using the intrinsic fluorescence, ANS fluorescence and CD spectrum. It has been found that the conformation and activity of this cellulase were strongly dependent on the pH. EGX was stable for both the enzyme activity and the conformation from pH 5.6 to pH 7.4. As shown by intrinsic and ANS fluorescence, no red shift of emission maximum occurred and a negligible intensity change was observed at pH 5.6–7.4. The activity of EGX remained about 80% in pH 5.6–7.4 and obviously decreased out of side the pH range. Urea-induced changes in EGX at pH 5.4 and pH 8.0 were measured by intrinsic fluorescence and CD spectrum. At pH 5.4, a significantly red shift of emission maximum occurred when the concentration of urea was 5 M compared to the concentration was 3 M at pH 8.0. The α-helix at pH 5.4 was 40.51% in the absence of urea and 31.04% in the presence of 4 M urea. At pH 8.0 the α-helix was 7.23% in the presence of 4 M urea. The data indicated that EGX was much susceptible to urea-induced unfolding at pH 8.0 and much stable at pH 5.4. The greater pH dependent stability of EGX may allow the enzyme to adequately catalyze the hydrolysis of cellulosic materials under natural or industrial extreme conditions.

关键词： multi-functional cellulase stability Ampullaria crossean fluorescence spectroscopy pH-dependent structural change CD spectrum

Structural Analysis and Identification of Cis-Elements of Rice osRACD Gene

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Acta Biochimica et Biophysica Sinica 2004年第3期36卷 191-198页

作者： Yun-Zhe XU, Rui-Lin YOU and Nai-Hu WU Institute of Genetics and Developmental Biology, Chinese Academy of sciences, Beijing 100080, china 2College of life sciences, Peking university, Beijing 100871, china Institute of Genetics and Developmental Biology Chinese Academy of Sciences College of life sciences Peking University

The osRACD gene correlated with fertility transformation in the photoperiod sensitive genic male sterile rice (PGMR), Nongken 58S, encoded a rice (Oryza sativa L. ssp. japonica) small GTPase belonging to the Rac/Rho family. Inverse PCR was performed to amplify a fragment about 1.4 kb in 5' upstream region of the osRACD promoter. Deletion mutation and gel mobility shift assay characterized two fragments (–799 to –686 nt, and –686 to –431 nt) in the osRACD promoter that could be involved in its transcriptional regulation. When these two deletion fragments were used as probe respectively, a retarded band appeared in the nuclear extracts of fertile 58S rice under short day (58S-SD). Whereas no retarded band was shown in the nuclear extracts of sterile 58S rice under long day (58S-LD). Competition assay indicated that the factors in the retarded bands binding to these two fragments were the same trans-acting factor (termed rice factor, RF). The binding affinity of RF was affected by phosphorylation and was higher in SD-growth rice than that of LD-growth rice.

关键词： photoperiod-sensitive male genic sterile rice osRACD gene photoperiod fertility transformation cis-element

GM-CSF-induced Ca_(2+) -activated non-voltage-dependent inwardly rectifying K_+ channel in murine peritoneal exudate macrophages

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Chinese Science Bulletin 1997年第11期42卷 947-952页

作者： ZHANG Xiaofeng, FENG Meifu, WU Caihong and ZHOU Pei’aiState Key Laboratory of Biomembrane and Membrane Biotechnology, Chinese Academy of sciences, Beijing 100080, china 1 . In-stitute of Zoology, Chinese Academy of sciences, Beijing 100080, china 2 College of life sciences, Peking university, Beijing 100871, china State Key Laboratory of Biomembrane and Membrane Biotechnology Chinese Academy of Sciences Beijing 100080 China

GRANULOCYTE-MACROPHAGE colony-stimulating factor(GM-CSF),a member in the family ofglycoprotein cytokines,can not only act to stimulate proliferation of immature progenitors,butalso enhance differentiated functions of mature effector *** has two kinds of biologicaleffects on mature effector cells,*** effect and indirect *** latter is also

关键词： K+ channel patch clamp GM-CSF macrophage.

Synchronization of Delayed Chaotic Neural Networks with Stochastic Disturbances via Periodically Intermittent Control

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Synchronization of Delayed Chaotic Neural Networks with Stoc...

Power functions with low uniformity on odd characteristic finite fields

2011 Chinese Control and Decision Conference（CCDC）

作者： Yan Chen,Guiyin Shi and Hongji Tang are with school of Science,nantong university,nantong 226007,china Xiaomei Zhang,is with school of Electronics and Information,nantong university,nantong 226019,china

This paper deals with the synchronization problem of delayed chaotic neural networks with stochastic disturbances using periodically intermittent *** stability theory and free-weighting matrix method are utilized to establish stochastic synchronization criteria for designing intermittent control law,which guarantees that the synchronization error system is exponentially stable in the mean *** the assumption that the control period and control width are fixed and known,the desired intermittent controller is designed in terms of linear matrix inequalities.A numerical example is illustrated to demonstrate the effectiveness of the proposed method.

关键词： Chaotic neural networks stochastic synchronization intermittent control time delay mean square exponential stability

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Science china Mathematics 2010年第8期53卷 1931-1940页

作者： ZHA ZhengBang 1,3 & WANG XueLi 2 1 school of Mathematical sciences,Luoyang Normal university,Luoyang 471022,china 2.school of Mathematical sciences,South china Normal university,Guangzhou 510631,china 3 State Key Laboratory of Information Security,Graduate university of Chinese Academy of sciences,Beijing 100049,china 1. school of Mathematical sciences Luoyang Normal University Luoyang 471022 China3. State Key Laboratory of Information Security Graduate University of Chinese Academy of Sciences Beijing 100049 China2. School of Mathematical Sciences South China Normal University Guangzhou 510631 China

In this paper,we give some new low differential uniformity of some power functions defined on finite fields with odd *** corollaries of the uniformity,we obtain two families of almost perfect nonlinear functions in GF... 详细信息

关键词： almost perfect nonlinear function differential uniform function finite field