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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 Technology(Materials {2.) 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

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 {2. of Technology, Zibo 2.5049, China 2. Civil Engineering department, Dalian {2. of Technology, Dalian 11602., China 3. Mathematics department, Ocean {2. of China, Qingdao 2.6071, 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.

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 Technology, 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.

Inhibition of ethanol-induced toxicity by tanshinone ⅡA in PC12.cells

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Acta Pharmacologica Sinica 2006年第6期27卷 659-664页

作者： Xian-fang MENG~2.Xiao-jing ZOU~3.Bin PENG~2.Jing SHI~2.Xin-min GUAN~2.Chun ZHANG~(4,5)2.department of Neurobiology,Tongji Medical College,huazhong {2. of science and Technology,wuhan 43.03.,China 3.department of Anesthesiology,4 department of Nephrology,Union Hospital,Tongji Medical College,huazhong {2. of science and Technology,wuhan 43.02..China department of Neurobiology Tongji Medical College Huazhong University of Science and Technology Wuhan China department of Anesthesiology Union Hospital Tongji Medical College Huazhong University of Science and Technology Wuhan China department of Nephrology Union Hospital Tongji Medical College Huazhong University of Science and Technology Wuhan China

Aim:To observe the effects of tanshinone IIA(Tan IIA)on the neurotoxicityinduced by ethanol in PC 12.cells and to explore its protective ***:PC 12.ell survival was measured by MTT *** formation of reactive oxygenspecies(ROS)and lactate dehydrogenase(LDH)release were detected by 2.,7′-dichlorofluorescin(DCF)fluorescence and calorimetric method,*** of cell apoptosis was monitored by flow *** expression ofp53.was detected by immuno-fluorescence and flow ***:Ethanolsignificantly impaired the survival of PC12.cells as demonstrated by MTT *** also induced significant ROS formation and increased LDH ***-incubation with Tan IIA in the culture medium significantly reversed these *** caused cell apoptosis and the upregulation of p53.*** anti-apoptosis effects of Tan IIA on ethanol-induced toxicity were accompanied by thedownregulation of pro-apoptotic p53.protein ***:Tan IIAcan protect neurons from apoptosis and might serve as a potential therapeuticdrug for neurological disorders induced by ethanol.

关键词： apoptosis ethanol PC12.cells p53 tanshinone ⅡA

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 Technology, 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 Technology 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.

On the new results of global attractive set and positive invariant set of the Lorenz chaotic system and the applications to chaos control and synchronization

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science in China(Series F) 2005年第3期48卷 304-321页

作者： LIAO Xiaoxin 1, 2. 3., FU Yuli 4 & XIE Shengli 4 1. department of Control science & Control Engineering, {2. university of science & Technology, wuhan 43.074, China 2. School of Automation, wuhan university of science & Technology, wuhan 43.070, China 3. School of Information, Central South university of Economy, Politics and Law, wuhan 43.064, China 4. School of Electronics & Information Engineering, South China university of Technology, Guangzhou 510640, China Correspondence should be addressed to Liao Xiaoxin (email: xiaoxin_liao@***) 1. department of Control science & Control Engineering Huazhong University of Science & Technology 430074 Wuhan China 2. School of Automation Wuhan University of Science & Technology 430070 Wuhan China 3. School of Information Central South University of Economy Politics and Law 430064 Wuhan China 4. School of Electronics & Information Engineering South China University of Technology 510640 Guangzhou China

Constructing a family of generalized Lyapunov functions, a new method is proposed to obtain new global attractive set and positive invariant set of the Lorenz chaotic system. The method we proposed greatly simplifies the complex proofs of the two famous estimations presented by the Russian scholar Leonov. Our uniform formula can derive a series of the new estimations. Employing the idea of intersection in set theory, we extract a new Leonov formula-like estimation from the family of the estimations. With our method and the new estimation, one can confirm that there are no equilibrium, periodic solutions, almost periodic motions, wandering motions or other chaotic attractors outside the global attractive set. The Lorenz butterfly-like singular attractors are located in the global attractive set only. This result is applied to the chaos control and chaos synchronization. Some feedback control laws are obtained to guarantee that all the trajectories of the Lorenz systems track a periodic solution, or globally stabilize an unstable (or locally stable but not globally asymptotically stable) equilibrium. Further, some new global exponential chaos synchronization results are presented. Our new method and the new results are expected to be applied in real secure communication systems.

关键词： Lorenz chaotic system global attractive set positive invariant set globally exponential tracking globally exponential synchronization.

Spectral anomalies and spectral switches of partially coherent and polychromatic light diffracted at an aperture

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science China(Physics,mechanics & Astronomy) 2004年第1期47卷 24-35页

作者： Lü Baida1, 3.& PAN Liuzhan1, 2.1. Institute of Laser Physics and Chemistry, Sichuan university, Chengdu 610064, China 2. {3. of Physics, Luoyang Normal College, Luoyang 47102., China 3. State Key Laboratory of Laser Technology, {2. university of science and Technology, wuhan 43.074, China Correspondence should be addressed to L Baida (email: badalu@***) Received July 10, 2.03 1. Institute of Laser Physics and Chemistry Sichuan University 610064 Chengdu China 2. State Key Laboratory of Laser Technology Huazhong University of Science and Technology 430074 Wuhan China 3. department of Physics Luoyang Normal College 471022 Luoyang China

Based on the propagation theory of partially coherent light in the space-frequency domain, the anomalous spectral behavior and spectral switches in the far field of partially coherent and polychromatic light diffracted at an aperture are studied. It is shown that, as compared with spatially fully coherent and polychromatic light whose spectral anomalies are induced only by aperture diffraction, the spectral anomalies and spectral switches of partially coherent and polychromatic light depend on the aperture diffraction, spatial correlationβ and bandwidth of the original spectrum. Detailed numerical calculations are made to illustrate the behavior of spectral switches of partially coherent and polychromatic light, and the results for spatially fully coherent and polychromatic light are treated as a special case ofβ=1 and included in our theory.

关键词： spectral anomaly spectral switch partially coherent and polychromatic light far field aperture diffraction

3.D Lightning Location Solution and Precision Analysis of Cloud Flash

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wuhan university Journal of Natural {2.s 2009年第3期14卷 241-244页

作者： ZHANG Ping1,2. ZHAO Wenguang2.3., HU Zhixiang2.3. WEN Yinping2.3.1. School of Architecture and Urban Planning, huazhong university of {2. and Technology, wuhan 43.074, Hubei, China 2. School of Civil Engineering and mechanics, huazhong university of {2. and Technology, wuhan 43.074, Hubei, China 3. Hubei Key Laboratory of Control Structure, huazhong university of {2. and Technology, wuhan 43.074, Hubei, China School of Architecture and Urban Planning Huazhong University of Science and Technology Wuhan 430074 Hubei China School of Civil Engineering and mechanics Huazhong University of Science and Technology Wuhan 430074 Hubei China Hubei Key Laboratory of Control Structure Huazhong University of Science and Technology Wuhan 430074 Hubei China

Using the spatial coordinates of detection stations and the time of arrival of lightning wave, the observation equations can be expressed. For the large lightning detection network, the least square method is used to process the adjustment of observation data to find the most probable value of lightning position, and the result is assessed by the mean error and dilution of precision. Lightning location precision is affected by figure factor. The conclusion can be used in the design of location network, data processing, and data analysis.

关键词： 3.D lightning location cloud flash detection solution model dilution of precision figure factor

Structure and Magnetic Properties of Ni-doped ZnO Powder

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Journal of wuhan university of Technology(Materials {2.) 2010年第5期25卷 770-773页

作者：高放赵俊 department of Electronic science and Technology Huazhong University of Science and Technology

Ni-doped ZnO nanopowder （Zn0.98Ni0.2.） was synthesized by improved coprecipitation method. The average particle size of the powder was estimated to be 50 nm. The powder was then processed by thermal treatment. Samples were annealed at 1 073. 1 2.3. and 1 473.K, respectively. The solubility of NiO in ZnO and the lattice parameters of ZnO both increased with the temperature. The magnetic property of the doped samples was examined, and hysteresis loops were got. The results showed all the samples were ferromagnetic, while powder processed at 1 2.3.K for 4 h got a highest saturation magnetization （Ms） of 0.0457 emu/g. Also, magnetic properties were related to the grain size of the powder.

关键词： ferromagnetism diluted magnetic semiconductor Ni-doped ZnO coprecipitation solid state reaction