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Gas hydrate fast nucleation from melting ice and quiescent growth along vertical heat transfer tube

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Science china Chemistry 2005年第1期48卷 75-82页

作者： XIE Yingming1,2. GUO Kaihua2. LIANG Deqing2. FAN Shuanshi2. GU Jianming1 & CHEN Jinggui2.1. Institute of Refrigeration and Cryogenics, shanghai Jiaotong University, shanghai 2.0030, {2. 2. Guangzhou Institute of Energy Conversion, The Chinese Academy of sciences, Guangzhou 510640, {2. 1. Institute of Refrigeration and Cryogenics Shanghai Jiaotong University 200030 Shanghai China 2. Guangzhou Institute of Energy Conversion The Chinese Academy of Sciences 510640 Guangzhou China

During the observation of HCFC141b gas hydrate growth processes outside a ver- tical heat transfer tube, two exciting phenomena were found: fast nucleation of gas hydrate from melting ice, and the spontaneous permeation of water into the guest phases along the surface of heat transfer tube to form gas hydrate continuously. These two phenomena were explained with Zhou & Sloan’s hypothesis and the theory of surface free energy respectively, and a novel method of gas hydrate formation was presented——gas hydrate fast nucleation from melting ice and quiescent growth along heat transfer tube. There is no mechanic stirring in this method, the formed gas hydrates are compact, the ratio of unreacted interstitial water is little, which overcome the drawback of high energy cost and high ratio of unreacted interstitial water among the formed gas hydrates in the system with mechanic stirring. This finding will benefit the gas hydrate ap- plication technologies such as natural gas storage technology or cool storage technology with gas hydrate.

关键词： gas hydrate, natural gas storage, cool storage, fast nucleation from melting ice, permeation, surface free energy.

SOBOLEV INEQUALITY ON RIEMANNIAN MANIFOLDS

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Chinese Annals of Mathematics,Series B 2005年第4期26卷 651-658页

作者： WANG MENG Department of Mathematics, Zhejiang University, Hangzhou 31002., china school of {2. sciences, Pudan University, shanghai 2.0433, china. Department of Mathematics Zhejiang University Hangzhou 310027 China. school of mathematical {2. Fudan University Shanghai 200433 China

Let M be an n dimensional complete Riemannian manifold satisfying the doublingvolume property and an on-diagonal heat kernel estimate. The necessary-sufficientcondition for the Sobolev inequality ‖f‖q ≤ Cn,,v,p,q(... 详细信息

关键词： Sobolev inequality Complete manifold Riesz transform Potential Heat kernel

Simulation of nuclei morphologies for binary alloy

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Science china Mathematics 2010年第11期53卷 2927-2936页

作者： LI DaMing1, & ZHANG PingWen2.1Department of Mathematics, shanghai Jiaotong University, shanghai 2.02.0, {2. 2.ey Lab of Mathematics and Applied Mathematics, Center for Applied Physics and Technology and school of mathematical sciences, Peking University, Beijing 100871, {2. 1. Department of Mathematics Shanghai Jiaotong University Shanghai 200240 China2. Key Lab of Mathematics and Applied Mathematics Center for Applied Physics and Technology and School of Mathematical Sciences Peking University Beijing 100871 China

We study the critical nuclei morphologies of a binary alloy by the string method. The dynamic equation of the string, connecting the metastable phase (liquid) and stable phase (solid), is governed by Helmholtz free energy for the binary alloy system at a given temperature. The stationary string through the critical nucleus (saddle point) is obtained if the relaxation time of the string is su?ciently large. The critical nucleus radius and energy barrier to nucleation of a pure alloy with isotropic interface energy in two and three dimensions are calculated, which are consistent with the classical nucleation theory. The critical nuclei morphologies are sensitive to the anisotropy strength of interface energy and interface thickness of alloy in two and three dimensions. The critical nucleus and energy barrier to nucleation become smaller if the anisotropy strength of the interface energy is increased, which means that it is much easier to form a stable nucleus if the anisotropy of the interface energy is considered.

关键词： nucleation crystal morphology string method

Compact Operators on Weighted Bergman Spaces of the Unit Ball

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Journal of mathematical Research with Applications 2012年第1期32卷 83-94页

作者： Jun YANG 1,Yu Feng LU 2.1.College of Arts and sciences,shanghai Maritime University,shanghai 2.1306,P.R.china 2.school of mathematical sciences,Dalian University of Technology,Liaoning 11602.,P.R.china College of Arts and sciences Shanghai Maritime University Shanghai 201306 school of mathematical {2. Dalian University of Technology Liaoning 116024

In this paper,we study the compact operators on weighted Bergman spaces of the unit *** Miao and Zheng'result in 2.04,we obtain the necessary and sufficient conditions for the operator to be compact on weighted Bergma... 详细信息

关键词： compact operator unit ball weighted Bergman space.

Serine racemase expression in mouse cerebral cortex after permanent focal cerebral ischemia

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Acta Pharmacologica Sinica 2004年第4期25卷 38-43页

作者： Li-zhenWANG, Xing-zu ZHU2.Department of Pharmacology, shanghai Institute of Materia Medica, shanghai Institutes for Biological {2., Chinese Academy of {2., shanghai 2.12.3, china Department of Pharmacology Shanghai Institute of Materia MedicaShanghai Institutes for Biological Sciences Chinese Academy of Sciences

AIM: To study the alterations of the expressions of serine racemase in C57BL/6 mouse brain after permanent focal cerebral ischemia. METHODS: The mRNA level and the protein level of serine racemase were assayed by semiquantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blot, respectively. The amount of D-serine and L-serine were measured by HPLC. RESULTS: High levels of serine racemase were constitutively expressed in the normal cortex of mouse. At early stage after middle cerebral artery occlusion (MCAO), no significant change in expression of serine racemase was observed in temporoparietal cortex in ipsila- teral hemisphere. However, delayed transient decreases of serine racemase in both mRNA and protein levels were detected from d 6 to d 10 after ischemia. Correspondingly, D-serine concentration also declined in the ipsilateral cortex during this period when compared with the D-serine level in the contralateral cortex. CONCLUSION: Delayed decreases in serine racemase expression and D-serine level occurred in the temporoparietal cortex at the late stage after focal cerebral ischemia.

关键词： D-serine L-serine serine racemase inbred C57BL mice brain ischemia

Anticoagulation property and security of artificial heart valve material

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Science china(Technological sciences) 2005年第2期48卷 145-162页

作者： WANG Xianghui1, , LIU Xianghuai1,2., 3, ZHANG Feng2. LI Changrong2. YU Liujiang2. ZHENG Zhihong2. WANG Xi2. JIANG Zhenbin4, CHEN Anqing4 & XU Jingfang3 1. Department of Physics, East china Normal University, shanghai 2.0062. china 2. Ion Beam Lab, shanghai Institute of Mini-system and information, Chinese Academy of sciences,shanghai 2.0050, china 3. Department of Electronics, school of Information Science and Technology, East china Normal Univer- sity, shanghai 2.0062. china 4. shanghai Cardiovascular Institute, Zhongshan Hospital, shanghai 2.0032. china 1. Department of Physics East China Normal University 200062 Shanghai China 2. Ion Beam Lab Shanghai Institute of Mini-system and information Chinese Academy of Sciences 200050 Shanghai China 3. Department of Electronics School of Information Science and Technology East China Normal University 200062 Shanghai China 4. shanghai Cardiovascular Institute Zhongshan Hospital 200032 Shanghai China

Heart valve diseases threaten human health. One reliable way to save lives of such patients is to replace the pathologically changed heart valves by artificial ones. Over 2.million patients have received LTI-carbon heart valve’s implantation. However, the thrombosis after the implantation is one of the difficulties that need to be solved. In order to improve the blood compatibility and security of mechanical heart valves, ion beam technology was used to modify the surface properties of the materials. The investigation results have been summarized in this paper.

关键词： artificial heart valve, ion implantation, plasma immersed ion implantation, ion beam enhanced deposition.

Population-size-dependent branching processes in Markovian random environments

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Chinese Science Bulletin 1998年第8期43卷 635-638页

作者： WANG Hanxing 1 and DAI Yonglong 2.1. Department of Mathematics, shanghai University, shanghai 2.1800, {2. 2. Department of Mathematics, Zhongshan University, Guangzhou 5102.5, {2. Department of Mathematics Shanghai University Shanghai China Department of Mathematics Zhongshan University Gunngzhou China

A branching model {Z n} n≥0is considered where the offspring distribution of the population’s evolution is not only dependent on the population size, but also controlled by a Markovian environmental process {ξ n} n≥0. For this model, asymptotic behaviour is studied such as limn→∞Z n and limn→∞Z n/m n in the case that the mean m k, θof the offspring distribution converges to m>1 as the population size k grows to ∞. In the case that {ξ n} n≥0is an irreducible positive recurrent Markov chain, certain extinction (i.e. P(Z n=0 for some n)=1) and noncertain extinction (i.e. P(Z n=0 for some n)<1) are studied.

关键词： Markov chains in random environments stochastic population models branching processes.

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 2.0031, china 2.ollege 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

Effect of Cold Rolling on Microstructure and Mechanical Properties of AISI 301LN Metastable Austenitic Stainless Steels

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Journal of Iron and Steel Research International 2012年第10期19卷 59-63页

作者： HUANG Jun-xia1, YE Xiao-ning1, XU Zhou2.(1. shanghai Baosteel Research Institute, shanghai 2.0431, {2. 2. school of Material Science and Engineering, shanghai Jiao Tong University, shanghai 2.02.0, {2.) [a] shanghai Baosteel Research Institute Shanghai 200431 China [b] school of Material Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China

The microstructure and mechanical properties evolution of AISI 301LN metastable austenitic stainless steels during cold rolling were investigated. A wide range of cold thickness reduction (10%-80%) was carried out in a four-high rolling mill at ambient temperature. The X-ray and Feritscope MP30 were used to identify the strain-induced α′-martensite phase and its volume fraction, respectively. The microstructure was observed by optical micrograph and the mechanical properties were determined by tensile tests and microhardness. The results show that the strain-induced α′-martensite nucleated at the shear bands intersections and the growth of α′-martensite occurred by the repeated nucleation of new embryos. The volume fraction of strain-induced α′-martensite increased with increasing the cold rolling reduction. In addition, the percentage increased in the tensile strength is the same as that of hardness. The ratio between the average tensile strength and the average microhardness was found to range between 2.82.and 3.17.

关键词： metastable austenitic stainless steel cold rolling reduction strength