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Interfacial Microstructure and Properties of Ti(C, N)/Ni Bonded by Transient Liquid-phase Diffusion

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Journal of wuhan university of {2.(Materials {3.) 2009年第3期24卷 432-439页

作者：周世权熊惟皓 School of Mechanical science and Engineering Huazhong University of Science and Technology Department of Mechanical Engineering University of Waterloo School of Materials science and Engineering Huazhong University of Science and Technology

Effects of the main process parameters（temperature and time） on microstructure and properties of Ti（C, N）/Ni interface bonded by （Cu＋Nb） interlayer in a vacuum diffusion bonding device were investigated. The interfacial microstructures consisted initially of Ni3.b metallic compound and eutectic of Ni3.b ＋ CuNiss, and finally transformed to （Ti, Nb）（C, N）＋Ni3.b near Ti （C, N） and NiCuss ＋ Ni3.b near Ni when diffusion bonding temperature was 1 52.-1 573.K. It was clear that Cu was a constituent in the transient liquid phase （TLP） into which Ni was dissolved by forming Cu-Ni transition liquid. Nb was dissolved in Cu-Ni transition liquid rapidly. Ti （C, N） conld be wetted by resultant Ni-Nb-Cu transient liquid phase which was followed by a little （Ti, Nb）（C, N） solid solution formed at interface. This increased the interface combining capability. Ultimately the interface shear strength was able to reach 140 MPa. The theoretle analysis and experimental results show that the growth of interfacial reaction layer Ni3.b accords with parabola law, and the activation energy of diffusion reaction is 115.0±0.5 kJ/mol, while the diffusion reaction speed constant is 12.53.mm/s^1/2.

关键词： vacuum diffusion bonding transient liquid phase (TLP) diffusion bonding interlayer activation energy

Nitrogen isotopic geochemical characteristics of crude oils in several basins of China

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science China Earth sciences 2005年第8期48卷 1211-1219页

作者： CHEN Chuanping1,2. MEI Bowen1 & CAO Yacheng3.1. Jianghan Petroleum university, Jingzhou 43.100, China 2. {3., {2. 43.047, China 3. Nanjing {3. of Soil science, Chinese Academy of sciences, Nanjing 2.0008, China 1. Jianghan Petroleum university 434100 Jingzhou China 2. huazhong university of science and technology 430047 Wuhan China 3. Nanjing institute of Soil science Chinese Academy of Sciences 210008 Nanjing China

Nitrogen isotopic ratios of crude oils with different physical and chemical properties in several basins of China have been measured and their geochemistry has been studied ele-mentally combined with molecular organic geochemistry methods. The data indicate that δ 15N is in the range of ?6‰-2.‰. They vary with the oils in different sedimentary types of basins. The oils forming in the limnic environment have lower δ 15N with the value of about 1‰-5‰ whereas the oils in saline or semi-saline environment have higher δ 15N, with most samples being above 10‰ and some exceeding 17‰. The average nitrogen isotopic ratio of oils from the Ordovician formation in the Tarim Basin is the lowest, with most samples having δ 15N below zero, which reflects possibly the characteristic of the oils originating mainly from the organic matter formed in marine carbonate sedimentary environment. The δ 15N distribution can be altered by fractionation. It increases obviously because of biodegradation and decreases during hydrocarbon migration. However, the effect of nitrogen isotopic fractionation in the short distance migration is uncon-spicuous.

关键词： nitrogen isotope, crude oil, sedimentary environment, isotopic fractionation, China.

A low frequency piezoelectric power harvester using a spiral-shaped bimorph

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science China(Physics,Mechanics & Astronomy) 2006年第6期49卷 649-659页

作者： HU Yuantai1,2.HU Hongping2.& YANG Jiashi3.1. institute of Mechanics and Sensing {3.,Central South {2.,Changsha 410083.China 2. Department of Mechanics,{3.,wuhan 43.074,China 3. Department of Engineering Mechanics,{2. of Nebraska,Lincoln,NE 68588-052.,USA 1. institute of Mechanics and Sensing technology Central South University Changsha 410083 China 2. Department of Mechanics Huazhong University of Science and Technology Wuhan 430074 China 3. Department of Engineering Mechanics University of Nebraska Lincoln NE 68588-0526 USA

We propose a spiral-shaped piezoelectric bimorph power harvester operating with coupled flexural and extensional vibration modes for applications to low frequency energy sources. A theoretical analysis is performed and the computational results show that the spiral structure has relatively low operating frequency compared to beam power harvesters of the same size. It is found that to optimize the performance of a piezoelectric spiral-shaped harvester careful design is needed.

关键词： spiral-shaped bimorph,piezoelectric harvester,power density.

Peplomycin induces G1-phase specific apoptosis in liver carcinoma cell line Bel-7402.involving G2.phase arrest

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Acta Pharmacologica Sinica 2004年第12期25卷 132-138页

作者： Hong-ying CHEN2. Cong-yi ZHENG2. Guo-lin ZOU2. Da-xing XIE3. Jian-ping GONG3. 2.ollege of Life sciences, wuhan {2., wuhan 43.072.3.ancer Research institute, Tongji Hospital, TongjiMedical College, huazhong university of science and technology, wuhan 43.072. China College of Life sciences Wuhan University Wuhan 430072 China

AIM: To investigate the mechanism of peplomycin (PEP)-induced apoptosis in liver carcinoma cell line (Bel-7402.. METHODS: Growth inhibition by PEP was analyzed using 3. 4,5-Dimethylthiazol-2.yl-2.5-diphenyltetrazolium bromide (MTT) assay. Apoptotic cells were detected using Hoechest 3.2.8 staining, and confirmed by flow cytometric analysis and DNA fragmentation analysis. The expression of cyclin A and B1 were determined by flow cytometry and Western blot. Annexin V assay was measured by flow cytometric analysis. RESULTS: PEP induced apoptosis and then inhibited cell proliferation in liver carcinoma cell line Bel-7402. Cells treated with PEP 50 μmol/Lfor 15 h were arrested in G2.phase with dramatical expression of cyclin A and a little change in cyclin B1. Almost all the apoptosis occurred in cells undergoing the G1-phase after treatment for 2. h. CONCLUSION: Peplomycin induced G1-phase specific apoptosis in Bel-7402.involving G2.phase arrest.

关键词： peplomycin Bel-7402.cells apoptosis cyclins cell cycle flow cytometry

A study of two-dimensional magnetic polaron

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science China(Physics,Mechanics & Astronomy) 2006年第4期49卷 421-429页

作者： LIU Tao1, ZHANG Huaihong1, FENG Mang1,2.& WANG Kelin1,3.1. School of science, Southwest university of science and {3., Mianyang 62.010, China 2. wuhan institute of Physics and Mathematics, Chinese Academy of sciences, wuhan 43.070, China 3. Department of Modern Physics, university of science and {3. of China, Hefei 2.002., China School of science Southwest University of Science technology Mianyang 621010 China wuhan institute of Physics Mathematics Chinese Academy of Sciences Wuhan 430070 China Department of Modern Physics University of Science technology of China Hefei 230026 China

By using the variational method and anneal simulation, we study in this paper the self-trapped magnetic polaron (STMP) in two-dimensional anti-ferromagnetic material and the bound magnetic polaron (BMP) in ferromagnetic material. Schwinger angular momentum theory is applied to changing the problem into a coupling problem of carriers and two types of Bosons. Our calculation shows that there are single-peak and multi-peak structures in the two-dimensional STMP. For the ferromagnetic material, the properties of the two-dimensional BMP are almost the same as that in one-dimensional case; but for the anti-ferromagnetic material, the two-dimensional STMP structure is much richer than the one-dimensional case.

关键词： self-trapped magnetic polaron, bound magnetic polaron, impurity potential, anti-ferromagnet.

Determination of the Thermal Expansion Coefficient of Concrete at Early Ages by Using Temperature-stress Testing Machine

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Journal of wuhan university of {2.(Materials {3.) 2006年第4期21卷 146-149页

作者：霍凯成 Hubei Key Laboratory of Roadway Bridge & Structure Engineering Wuhan University of TechnologyWuhan 430070China

By using the uptodate temperatuer-stress testing machine, the thermal expansion coefficient of concrete at early ages was studied and indicative conclusions were achieved ： temperature rising due to hydration heat is not directly correlated with cracking, but the temperature and stress evolation process should be taken into consideration in the same time. Proper chemical admixtures and mineral cornpasitions can improve the mechanical properties of concrete such as thermal expansion coefficient, which is very indicative in practice.

关键词： concrete coefficient of thermal expansion temperature-stress test

Sea level variations in the South China Sea inferred from satellite gravity,altimetry,and oceanographic data

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science China Earth sciences 2012年第10期55卷 1696-1701页

作者： FENG Wei 1,2.ZHONG Min 1,3.& XU HouZe 1,3.1 State Key Laboratory of Geodesy and Earth’s Dynamics,institute of Geodesy and Geophysics,Chinese Academy of sciences,{2. 43.077,China 2.Graduate {3. of Chinese Academy of sciences,Beijing 100049,China 3.institute of Geophysics,huazhong university of science and technology,wuhan 43.074,China 1. State Key Laboratory of Geodesy and Earth’s Dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Institute of Geophysics Huazhong University of Science and Technology Wuhan 430074 China

Sea level variations(SLVs) can be divided into two major components:the steric SLV and the mass-induced *** two components of SLV in the South China Sea(SCS) are studied by using satellite altimetry,GRACE(Gravity Recovery and Climate Experiment) satellite gravity,and oceanographic data on annual and inter-annual *** the annual timescale,the geographic distribution of mass-induced SLV's amplitude jointly estimated from altimetry and the ECCO(Estimation of the Circulation and Climate of the Ocean) model agrees very well with that from *** observes obvious seasonal mass-induced SLV in the SCS with annual amplitude of 2.7±0.4 cm,which is consistent with the annual amplitude of 2.7±0.3.cm estimated from the steric-corrected *** the inter-annual timescales,the mean SLV in the SCS shows a large oscillation,which is mainly caused by the steric *** trend of mean SLV inferred from altimetry in the SCS is 5.5±0.7 mm/yr for the period of 1993.2.09,which is significantly higher than the global sea level rise rate of 3.3.0.4 mm/yr in the same *** is no obvious trend signal in the mass-induced SLV detected from GRACE that indicates the water exchange between the SCS and its adjacent seas and land is in balance within the study period.

关键词： altimetry GRACE ECCO the South China Sea sea level variation

Second-order consensus in networks of dynamic agents with communication time-delays

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Journal of Systems Engineering and Electronics 2010年第1期21卷 88-94页

作者： Bo Yang1,2. Huajing Fang3. and Hua Wang4 1. School of Navigation, wuhan university of {2., wuhan 43.063. P. R. China 2. wuhan Second Ship Design and Research institute, wuhan 43.064, P. R. China 3. Department of Control science and Engineering, huazhong university of science and technology, wuhan 43.074, P. R. China 4. Department of Aerospace and Mechanical Engineering, Boston university, Boston MA02.15, USA School of Navigation Wuhan University of Technology Wuhan 430063 P. R. China wuhan Second Ship Design and Research institute Wuhan 430064 E R. China Department of Control science and Engineering Huazhong University of Science and Technology Wuhan 430074 P. R. China Department of Aerospace and Mechanical Engineering Boston University Boston MA02215 USA

This paper proposes second-order consensus protocols with time-delays and gives the measure of the robustness of the protocols to the time-delay existing in the network of agents with second-order dynamics. By employing a frequency domain method, it is proven that the information states and their time derivatives of all the agents in the network achieve consensus asymptotically, respectively, for appropriate communication timedelay if the topology of weighted network is connected. Particularly, a tight upper bound on the communication time-delay that can be tolerated in the dynamic network is found. The consensus protocols are distributed in the sense that each agent only needs information from its neighboring agents, which reduces the complexity of connections between neighboring agents significantly. Numerical simulation results are provided to demonstrate the effectiveness and the sharpness of the theoretical results for second-order consensus in networks in the presence of communication time-delays.

关键词： second-order consensus protocols dynamic networks algebraic graph theory frequency domain analysis com-munication constraints.

Ca^(2.) signals induced from calcium stores in pancreatic islet β cells

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Chinese science Bulletin 2000年第1期45卷 51-56页

作者： ZENG Xuhui, QU Anlian, LOU Xuelin, XU Jianhua, WANG Junjian, WU Hongxiu & ZHOU Zhuan1. institute of Biochemistry and Biophysics, huazhong university of science and technology, {2., China 2. Pharmacology, huazhong university of science and technology, {2., China 3. School of Life sciences, university of science and technology of China, Hefei 2.002., China Correspondence should be addressed to Zhou Zhuan. institute of Biochemistry and Biophysics Huazhong University of Science and Technology Wuhan China Pharmacology Huazhong University of Science and Technology Wuhan China School of Life sciences University of Science and Technology of China Hefei China

In single rat pancreatic βcells, using fura-2.microfluorometry to measure [Ca2.] response upon different stimuli, the ways of calcium regulation have been studied. When the extracellular calcium concentration was 2.5 mmol/L, either 60 mmol/L KCI, 2. mmol/L D-glucose or 0.1 mmol/L tolbutamide induced increase in [Ca2.]. Such increase in [Ca2.] was absent when the same stimuli were applied under zero extracellular calcium. These results indicate that the increase of [Ca2.] is induced by the activation of voltage-dependent calcium channels in p celis. The manifold forms of [Ca2.] change induced by glucose imply that the effects of glucose are complex. 5 mmol/L caffeine or 5 mmol/L MCh increase the [Ca2.], which is independent of the external calcium, suggesting that [Ca2.] can be regulated by Ca2. release from not only the IP3.sensitive but also the ryanodine sensitive calcium stores in p celis. The latency of Ca responses for IP3.pathway (5 s) is faster than that for ryanodine pathway (3. s), it is

关键词： pancreatic β cell [Ca2.]i calcium stores glucose fura-2.