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HYDROGEN PULVERIZATION OF Nb_3Al AND NbCr_2 ALLOYS

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中国有色金属学会会刊：英文版 1999年第S1期9卷 13-20页

作者： H. Hosoda and S. Hanada Institute for Materials Research, Tohoku university, Sendai 980 8577, japan

Measurements of hydrogen absorption desorption behavior of Nb Al alloys, Nb ss (Nb solid sloution), Nb ss +Nb 3Al, Nb 3Al, Nb 3Al+Nb 2Al, were carried out under hydrogen pressure from 0 to 3.4 MPa at 353 and 357 K, along with mircostructural observation and X ray diffraction analysis. It was found that single phase alloys of Nb ss and Nb 3Al are not pulverized regardless of a considerable amount of hydrogen absorption, while two phase alloys of Nb ss +Nb 3Al and Nb 3Al+Nb 2Al are readily pulverized. X ray diffraction analysis indicated that no hydride with crystal structure different from constituent phases is formed by hydrogen absorption, but lattice parameters of Nb ss and Nb 3Al are increased. Pulverization of Nb Cr alloys was investigated under a hydrogen atmosphere of 0.1 MPa in an arc melting chamber without exposure to air after arc melting. Similarly, hydrogen pulverization occurs only in two phase alloys consisting of Nb ss and NbCr 2. Based on the measured lattice parameters of Nb ss and Nb 3Al(NbCr 2) in the hydrogenated two phase alloys and the microstructural observations, a mechanism for hydrogen pulverization is discussed.

关键词： Nb 3Al NbCr 2 hydrogen pulverization hydrogen adsorption hydrogen desorption microstructural observations lattice parameters mechanism

Global existence of smooth solutions to two-dimensional compressible isentropic Euler equations for Chaplygin gases

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Science China Mathematics 2010年第3期53卷 719-738页

作者： KONG DeXing 1 , LIU KeFeng 2 & WANG YuZhu 3, 1 department of Mathematics, Zhejiang university, Hangzhou 310027, China 2 department of Mathematics, university of California at Los Angeles, CA 90095, USA 3 department of Mathematics, Shanghai Jiao Tong university, Shanghai 200248, China 1. department of Mathematics Zhejiang University Hangzhou 310027 China2. Department of Mathematics University of California at Los Angeles Los Angeles CA 90095 USA3. Department of Mathematics Shanghai Jiao Tong University Shanghai 200248 China

In this paper we investigate the two-dimensional compressible isentropic Euler equations for Chaplygin gases. Under the assumption that the initial data is close to a constant state and the vorticity of the initial velocity vanishes, we prove the global existence of the smooth solution to the Cauchy problem for twodimensional flow of Chaplygin gases.

关键词： Chaplygin gases compressible Euler equations irrotational flow null condition Cauchy problem smooth solution

CMC surfaces in the hyperbolic 3-space

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Chinese Science Bulletin 1998年第7期43卷 547-550页

作者： YU Zuhuan 1, 2 and LI Zhenqi 1, 3 1. Institute of Mathematics, Fudan university, Shanghai 200433, China 2. department of Mathematics,Sichuan Union university, Chengdu 610064, China 3. department of Mathematics, Nanchang university, Nanchang 33 nstitute of Mathemalics Fudan University Shanghai China department of Mathematics Sichuan Union University Chengdu China department of Mathematics Nanchang University Nanchang China

CMC-H surfaces satisfying H≥1 are studied. It is proved that these surfaces possess a natural representation which is a generalization of the Bryant’s result.

关键词： hyperbolic space CMC surface Weierstrass representation.

Analysis on cohesive crack opening displacement considering the strain softening effect

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Science China(Physics,Mechanics & Astronomy) 2006年第1期49卷 88-101页

作者： WANG Limin1, XU Shilang2 & ZHAO Xiqiang3 1. Mechanics department, Shandong university of Technology, Zibo 255049, China 2. Civil Engineering department, Dalian university of Technology, Dalian 116024, China 3. Mathematics department, Ocean university of China, Qingdao 266071, China Mechanics department Shandong University of Technology Zibo 255049 China Civil Engineering department Dalian University of Technology Dalian 116024 China Mathematics department Ocean University of China Qingdao 266071 China

In order to investigate the crack propagation in quasi-brittle materials like rock, ceramic and concrete, Hillerborg and his co-researchers abstracted the fracture process zone in front of a stress free crack in terms of a “fictitious crack zone”. On the fictitious crack zone, cohesive stresses distribute following a given softening relationship of stress vs. crack opening. Based on the polynomial or power series expression of cohesive crack opening displacement, the relationship of the cohesive stress vs. the crack opening displacement is established using elastic theory and integral equation, and some unknown physics variables are obtained using variation approach. The calculation results gained in this paper are close to the experimentally test ones.

关键词： cohesive crack, softening, dissipation work, variation approach.

A New and Effective Synthesis of Terminal Alkylselenylacetylenes

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Chinese Chemical Letters 1996年第12期7卷 1085-1086页

作者： De Yu YANG Xian HUANG Ping LI(department of Chemistry, Hangzhou university, Hangzhou 3 10028) HANGZHOU UNIV DEPT CHEMHANGZHOU 310028PEOPLES R CHINA

The terminal alkylselenylacetylenes (RSe-C = C-H) 3a-h were prepared by the reaction of ethynylmagnesium bromide at -20 degrees C in THF with alkylselenyl bromides derived from dialkyl diselenides and bromide.

关键词： A New and Effective Synthesis of Terminal Alkylselenylacetylenes

INFLUENCE OF WHEEL STRUCTURAL PARAMETERS ON MACHINING ACCURACY OF ULTRA-PRECISION PLANE HONING

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Chinese Journal of Mechanical Engineering 2002年第4期15卷 344-347页

作者： Guo Yinbiao department of Mechanical and Electrical Engineering, Xiamen university, Xiamen 361005, ChinaHu Jianyu Zheng Xiaoguang Katsuo SyojiXiamen university Chongqing university Tohoku university, japan department of Mechanical and Electrical Engineering Xiamen University Xiamen 361005 Xiamen university Chongqing university Tohoku university 日本

A new idea for designing wheel patterns is presented so as to solve theproblems about machining accuracy of workpiece and wear of honing wheel in ultra-precision planehoning. The influence factors on motion principle and pattern structures are analyzed andoptimization machining parameters are obtained. By calculating effective cutting length on thesurface of workpiece cut by wheel's abrasive and the orbit of one point on the surface of workpiececontacting with wheel, the wear coefficient of different kinds of wheels and accuracy coefficient ofworkpiece machined by corresponding wheels are obtained. Furthermore, the simulation results showthat the optimal pattern structure of wheel turns out to have lower wheel wear and higher machiningaccuracy.

关键词： fine grit diamond wheel ultra-precision plane honing machining accuracy wheel wear

N-way blending problem of circular quadrics

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Science China(Information Sciences) 2010年第8期53卷 1546-1554页

作者： FANG MeiE 1,3 , Wang GuoZhao 2 & MA WeiYin 3 1 School of Computer Science, Hangzhou Dianzi university, Hangzhou 310081, China 2 department of Mathematics, Zhejiang university, Hangzhou 310018, China 3 department of MEEM, City university of Hong Kong, Hong Kong, China 1. School of Computer Science Hangzhou Dianzi University Hangzhou 310081 China3. Department of MEEM City University of Hong Kong Hong Kong China2. Department of Mathematics Zhejiang University Hangzhou 310018 China

A method of blending circular quadrics with parametric patches is proposed in this paper. It needs n rational bi-cubic B′ezier patches and two S-patches to blend n (n > 2) quadrics. Bi-cubic rational B′ezier patches are used to G 1 -continuously blend each pair of adjacent base surfaces. These patches enclose two n-sided holes. And an S-patch is used to fill each hole, which keeps nearly G 1-continuity. Explicit formulas of control points for both B′ezier patches and S-patches are derived from their constraint conditions, which make modeling by blending quadrics very simple and convenient. In addition, the shapes of the blending surfaces can be intuitively adjusted by free parameters.

关键词： circular quadrics blending n-way S-patch

A New Tetranuclear Copper(Ⅰ) Complex of Dithiolate Ligand Fused with TTF Moiety

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Chinese Chemical Letters 1998年第5期9卷 481-482页

作者： Jie DAI Guo Qing BIAN and (department of Chemistry, Suzhou university, Suzhou 215006)Megumu MUNAKATA Yasuhiro OHNO Yusaku SUENAGA (department of Chemistry, Kinki university, Higashi-Osaka 577, japan) department of Chemistry Suzhou University Suzhou 215006 China department of Chemistry Kinki University Higashi-Osaka 577 Japan

A tetranuclear copper (I) complex of the ditholate ligand fused with a TTF moiety hasbeen synthesized and characterized crystallographically. This is the first example of a metaJ clustercoordinated with the new type l... 详细信息

关键词： copper (Ⅰ) complex TTF derivative crystal structure,cluster

An increase in opening of BKCa channels in smooth muscle cells in streptozotocin-induced diabetic mice

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Acta Pharmacologica Sinica 2004年第6期25卷 42-48页

作者： Chun-ling YE2, Bing SHEN4, Xian-da REN, Rong-jing LUO3, Sheng-yuan DING3, Fu-man YAN3, Jia-hua JIANG department of Pharmacology, Pharmacy College of Ji-nan university, Guangzhou 510632 3department of Physiology, Guangzhou university of Traditional Chinese Medicine, Guangzhou 510407 4department of Molecular Biology and Cell Biology, School ofLife Sciences, university of Sciences and Technology of China, Hefei 230036, China department of Pharmacology Pharmacy College of Ji-nan University Guangzhou 510632 Chin

AIM: To investigate the changes of function of large conductance of calcium-activated potassium channels (BKCa channels) in thoracic aortic smooth muscle cells in early stage of streptozotocin (STZ)-induced diabetic C57BL/6J mice. METHODS: Vascular muscle tension in the isolated thoracic aortic rings of mice was compared, and the role of BKCa channels in relaxation of isolated mice thoracic aortic rings induced by acetylcholine (ACh) was determined. Meanwhile, single vascular smooth muscle cells (VSMCs) were isolated by collagenase, and BKCa currents were recorded by patch-clamp single channel recording technique in symmetric high potassium solution. RESULTS: Tetraethylammonium (TEA) 1 mmol/L, a selective calcium-activated potassium channel blocker, caused significant rightward shift in the concentration-response curves of ACh in the isolated thoracic aortic rings of diabetic mice and pD2 value of ACh-induced relaxation was decreased notably after TEA treatment [(6.3±0.4) vs (6.9±0.5), n=10 rings from 7 mice, P0.05]. Furthermore, conductance of BKCa channels in single thoracic aortic smooth muscle cells was decreased [(199±15) pS, n=10 cells from 7 mice vs (266±11) pS, n=12 cells from 6 mice, P32±98), n=6 cells from 6 mice, P<0.05]. CONCLUSION: The opening of BKCa channels was increased in thoracic aortic smooth muscle cells in the early stage of STZ-induced diabetic C57BL/6J mice by reducing mean closed time, but the conductance of BKCa channels was decreased.

关键词： diabetes mellitus streptozotocin aorta patch-clamp techniques potassium channels calcium