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Boundary conditions for the bending of a piezoelectric beam

science china(Physics,Mechanics & Astronomy) 2008年第7期51卷 847-856页

作者： GAO Yang1, XU SiPeng2.& ZHAO BaoSheng3 1 College of science, china Agricultural University, Beijing 100083, china 2.College of engineering, Ocean University of china, Qingdao 2.6071, china 3 school of mechanical engineering, University of science and technology liaoning, anshan 114044, china 1. College of science China Agricultural University Beijing 100083 China 2. College of engineering Ocean University of China Qingdao 266071 China 3. school of mechanical {2. University of Science and Technology Liaoning Anshan 114044 China

For beam bending in transversely isotropic piezoelectric media, the reciprocal theorem and the general solution of piezoelasticity are applied in a novel way to obtain the appropriate stress and mixed boundary conditions accurate to all orders for the beam of general edge geometry and loadings. By generalizing the method developed by Gregory and Wan, a set of necessary conditions on the edge-data for the existence of a rapidly decaying solution is established. The prescribed edge-data of the beam must satisfy these conditions in order that they could generate a decaying state within the beam. When stress and mixed conditions are imposed on the beam edge, these decaying state conditions for the case of bending deformation of piezoelectric beam are derived explicitly. They are then used for the correct formulation of boundary conditions for the beam theory solution (or the interior solution). Besides, an analytical solution of elastic beam is formulated to verify validity of our boundary conditions. For the stress data, our boundary conditions coincide with those obtained in conventional forms of beam theories. More importantly, the appropriate boundary conditions with two sets of mixed edge-data are obtained for the first time.

关键词： boundary conditions beam bending piezoelectric media decaying states regular states

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Mixed boundary conditions for piezoelectric plates

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science china(Physics,Mechanics & Astronomy) 2009年第5期52卷 755-761页

作者： GAO Yang 1 ,XU SiPeng 2.&ZHAO BaoSheng 3 1College of science,china Agricultural University,Beijing 100083,china 2.ollege of engineering,Ocean University of china,Qingdao 2.6071,china 3 school of mechanical engineering,University of science and technology of liaoning,anshan 114044,china College of science China Agricultural University Beijing 100083 China College of engineering Ocean University of China Qingdao 266071 China school of mechanical {2. University of Science and Technology of Liaoning Anshan 114044 China

For plate bending and stretching problems in piezoelectric materials,the reciprocal theorem and the general solution of piezoelasticity are applied in a novel way to obtain the appropriate mixed boundary conditions accurate to all order.A decay analysis technique is used to establish necessary conditions that the prescribed data on the edge of the plate must satisfy in order that it should generate a decaying state within the *** the case of axisymmetric bending and stretching of a circular plate,these decaying state conditions are obtained explicitly for the first time when the mixed conditions are imposed on the plate *** are then used for the correct formulation of boundary conditions for the interior solution.

关键词： boundary conditions piezoelectric plates mixed data bending problems stretching problems

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The characteristics of arc beam shaping in hybrid plasma and laser deposition manufacturing

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science china(Technological sciences) 2006年第2期49卷 238-247页

作者： ZHANG Hai’ou1, QIAN Yingping1,3, WANG Guilan1 & ZHENG Qiguang2.1. school of Material science and {2., Huazhong University of science and {2., Wuhan 430074, china 2. Institute of Laser {2. and engineering, Huazhong University of science and {2., Wuhan 430074, china 3. mechanical engineering College, Hubei University of {2., Wuhan 430068, china 1. school of Material science and {2. Huazhong University of Science and Technology Wuhan 430074 China 3. mechanical engineering College Hubei University of Technology Wuhan 430068 China 2. Institute of Laser technology and engineering Huazhong University of Science and Technology Wuhan 430074 China

As a new direct metal prototyping technology,the hybrid plasma and laser deposition manufacturing (PLDM) is proposed in this paper. In order to figure out the characteristics of plasma arc beam and mould in the PLDM process of high temperature alloy, the high speed CCD camera is used to obtain the picture around the plasma arc. Afterwards the sketch of picture is clearly obtained. And the effect of laser parameter, such as average power, pulse width, pulse repetition frequency and the angle between laser beam and plasma arc beam on the plasma arc appearance, is studied experimentally. The results show that the modality of plasma arc beam is markedly influenced by laser beam. And the improvements of shape precision and surface state of the layer deposited by PLDM are confirmed.

关键词： plasma hybrid laser, direct deposition, plasma arc beam, molding character, high-temperature alloy.

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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 science) 2009年第3期24卷 432-439页

作者：周世权熊惟皓 school of mechanical {2. and engineering Huazhong University of Science and Technology Department of mechanical engineering University of Waterloo school of Materials science and {2. 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 Ni3Nb metallic compound and eutectic of Ni3Nb ＋ CuNiss, and finally transformed to （Ti, Nb）（C, N）＋Ni3Nb near Ti （C, N） and NiCuss ＋ Ni3Nb 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 Ni3Nb 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

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A New Genetic Algorithm Based on Niche Technique and Local Search Method

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Journal of University of science and technology Beijing 2001年第1期8卷 63-68页

作者： Jinwu Xu, Jiwen Liu mechanical engineering {2., University of science and technology Beijing, Beijing 100083, china Univ Sci & Technol Beijing Sch Mech Engn Beijing 100083 Peoples R China

The genetic algorithm has been widely used in many fields as an easy robust global search and optimization method. In this paper, a new generic algorithm based on niche technique and local search method is presented under the consideration of inadequacies of the simple genetic algorithm. In order to prove the adaptability and validity of the improved genetic algorithm, optimization problems of multimodal functions with equal peaks, unequal peaks and complicated peak distribution are discussed. The simulation results show that compared to other niching methods, this improved genetic algorithm has obvious potential on many respects, such as convergence speed, solution accuracy, ability of global optimization, etc.

关键词： genetic algorithm (GA) niche technique local search method

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Effect of Preparation Methods on mechanical Properties of PVA/HA Composite Hydrogel

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Journal of Bionic engineering 2010年第3期7卷 235-243页

作者： Dekun Zhang~1, Junjie Duan~1, Dagang Wang~2. Shirong Ge~2.1. school of Materials science and {2., china University of Mining and technology Xuzhou 2.1116, P. R. china 2. school of mechanical and Electrical {2., china University of Mining and technology, Xuzhou 2.1116, P. R. china [a] school of Materials science engineering China University of Mining technology Xuzhou 221116 P. R. China [b] School of Mechanical Electrical engineering China University of Mining technology Xuzhou 221116 P. R. China

Poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) composite hydrogel specimens were prepared with 15% PVA and 1%,2., 3%, 4% and 5% HA by repeated freezing-thawing. The tests of static and dynamic mechanical properties were carried out todiscuss the influence of different contents of HA and freezing-thawing cycles on the mechanical properties of PVA/HA compositehydrogel. The results of static mechanical tests showed that the PVA/HA composite hydrogel with 3% HA and ninefreezing-thawing cycles had excellent stress relaxation properties, higher relaxation ratio, lower stress equilibrium value andpresented better properties of creep and recovery. The results of dynamic mechanical test showed that the PVA/HA compositehydrogel with nine freezing-thawing cycles had higher storage modulus and loss modulus, so was the PVA/HA compositehydrogel with 3% HA.

关键词： composite hydrogel HA contents freezing-thawing cycles static properties dynamic properties

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Ferroelectric properties of Bi_(3.4)Ho_(0.6)Ti_3O_(12. thin films prepared by sol-gel method

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science china(Technological sciences) 2008年第9期51卷 1439-1444页

作者： FU ChengJu1, HUANG ZhiXiong1, LI Jie2.& GUO DongYun3 1 school of Materials science and {2., Wuhan University of {2., Wuhan 430070, china 2.school of mechanical engineering, Chongqing University of science and {2., Chongqing 400050, china 3 Department of Physics, Wuhan University, Wuhan 430072. china school of Materials science and {2. Wuhan University of Technology Wuhan 430070 China school of mechanical {2. Chongqing University of Science and Technology Chongqing 400050 China Department of Physics Wuhan University Wuhan 430072 China

We have prepared the Ho-substituted bismuth titanate (Bi3.4Ho0.6Ti3O12. BHT) thin films on Pt/Ti/SiO2.Si substrates using sol-gel method. The crystal structure and morphology of the films were characterized using X-ray diffraction and atomic force microscopy. The BHT film shows a single phase of Bi-layered Aurivillius structure and dense microstructure. The 2.r and 2.c of the 600-nm-thick BHT film were 38.4 μC/cm2.and 376.1 kV/cm, respectively at applied electric field 500 kV/cm. The dielectric constant and dielectric loss are about 310 and 0.015 at a frequency of 1 MHz, respectively. The Pr value decreased to 93% of its pre-fatigue values after 4.46×109 switching cycles at 1 MHz frenquency, and the BHT film shows good in-sulating behavior according to the test of leakage current.

关键词： Bi3.4Ho0.6Ti3O12 thin film sol-gel method ferroelectric property fatigue dielectric constant

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Kinetics analysis of volume phase transition of intelligent neutral thermo-sensitive hydrogels

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science china(Physics,Mechanics & Astronomy) 2008年第5期51卷 532-540页

作者： WANG XiaoGui1 & LI YiQuan2.1 College of mechanical engineering,Zhejiang University of {2.,Hangzhou 310032.china 2.school of mechanical & Electronic engineering,Changchun University of science and {2.,Changchun 13002.,china 1. College of mechanical engineering Zhejiang University of Technology Hangzhou 310032 China 2. school of mechanical & Electronic {2. Changchun University of Science and Technology Changchun 130022 China

In this work,utilizing the first law of thermodynamics and the Flory mean-field theory,the kinetic deformation studies concerning the volume phase transition of the neutral thermo-sensitive hydrogels were performed *** hydrogel was assumed as a biphasic mixture medium in the framework of the continuum mixture *** the energy conservation of the thermodynamics system of the hydrogel,the governing equations for the kinetics of the nonlinear large deforma-tion were *** explicit analytical expressions of the effective stress tensor and the chemical potential of the fluid of the thermo-sensitive hydrogel PNIPA were also obtained from the Helmholtz free energy,which can model the steady-static volume phase transition quantitatively.

关键词： thermo-sensitive hydrogel volume phase transition effective stress energy conservation

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New Solution to Surface Temperature of Casting Slab Measurement Based on Preceded Reflector and Multi-Wavelength

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Journal of Iron and Steel Research International 2012年第8期19卷 12-16页

作者： LIU Jun1, MA Jiao-cheng2. YANG Feng3, XIAO Hui1, RAO Li-min1 (1. school of Nuclear engineering and {2., East china Institute of {2., Fuzhou 344000, Jiangxi, china 2. school of mechanical engineering and Automation, Northeastern University, Shenyang 110004, liaoning, china 3. school of Civil and Environmental engineering, East china Institute of {2., Fuzhou 344000, Jiangxi, china) [a] school of Nuclear engineering and {2. East China Institute of Technology Fuzhou 344000 Jiangxi China [b] school of mechanical {2. and Automation Northeastern University Shenyang 110004 Liaoning China [c] school of Civil and Environmental engineering East China Institute of Technology Fuzhou 344000 Jiangxi China

The surface temperature of casting slab is an important parameter in the metallurgy field. Because the surface emissivity is uncertain and also unknown, it is difficult to measure the slab surface temperature accurately. A method based on preceded reflector and multi-wavelength was put forward to deal with the difficulty in surface temperature measurement of casting slab. On the premise of preceded reflector and non-preceded reflector, the method establishes the radiation energy equations and works out the emissivity and temperature in the equations. Also, the multilayer modeling of casting slab surface and multiple reflection-absorption process modeling were built by Monte Carlo method. The temperature measuring method had been applied in the continuous casting field. In order to verify the measured result, the thermal imaging method was adopted when the slab surface emissivity was set by repeated tests. Finally, the measured and verified temperature curves keep a same tendency and the error of the values is lower than 5℃. The comparison result shows that the method can measure temperature accurately.

关键词： casting slab emissivity surface temperature preceded reflector multi-wavelength

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Change Laws of Flake's Temperature during Making a Diamond Film by DC-PJ

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International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 97-102页

作者： Xuhong Chen Lihe Zhao Fanxiu Lu(mechanical engineering {2., University of science and technology Beijing, Beijing 100083, china) mechanical engineering {2. University of Science and Technology Beijing Beijing 100083 China

When making a diamond film by direct current plasma jet, a kind piece of flake is used as a base body Which the film can beattached to. The flake's temperature is unstable. Therefore, some experiments and constructed mathematical models, which were solvedby computer, were done. The results show that the flake's temperature is influenced by many factors and the mains are plasma jet powerand vacuum pressure. Through adjusting the two parameters, the flake's temperature can be accurately controlled, furthermore, diamondfilms' quality would be improved. Lowering sediment platform's temperature has a little effect to the flake's temperature at present technology conditions.

关键词： CVD (Chemical Vapor Deposition) plasma, impact heat transfer

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