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Heat treatment of novel low-carbon multi-alloyed anti-wear marine steel

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Progress in Natural science:Materials International 2011年第3期21卷 254-261页

作者： Jing-hua JIANG~(1,2.,Qiu-yue WANG~1,Ai-bin MA~(1,2.,Jun sHI~1,Liu-yan ZHANG~1, Hui-dong YANG~(2.3),Fu-min LU~2.Qi ZHOU~2.1.National engineering Research Center of Water Resources Efficient Utilization and engineering safety, Hohai {2.,Nanjing 2.0098,China 2.College of Mechanics and Materials,Hohai {2.,Nanjing 2.0098,China 3.department of mechanical and Aerospace engineering,North Carolina state {2., Raleigh,North Carolina 2.695-7919,UsA [a] National engineering Research Center of Water Resources Efficient Utilization and engineering safety Hohai University Nanjing 210098 China [b] College of Mechanics and Materials Hohai University Nanjing 210098 China [c] department of mechanical and Aerospace {2. North Carolina State University Raleigh North Carolina 27695-7919 USA

A low-carbon anti-wear steel,multi-alloyed with si-Cr-Mn-Al-Ni-Mo-（Nb,RE）,was designed for vane pumps of ships. The novel cast steel after various heat treatments was characterized by microstructure observations and mechanical properties measurement in order to achieve an optimal process correlated with good abrasive resistance for a long marine *** scanning calorimetry and hardness analyses deduced a complete austenitizing temperature of 1 000℃,based on the alloying element homogenization and defective structure elimination without grain *** optimal austempering process（austenitized at 1 000℃,quick cooled for holding at 350℃for 1.5 h and then air-cooled to room temperature） produced a uniform mixture structure of fine carbide-free aciculate bainites and few lath martensites,resulting in the tensile strength increase of 34%and impact toughness increase of 50%compared with that of the as-cast *** abrasive wheel tests show that the austempered steel has good wear resistance with a mass-loss rate of 170 mg/（km·cm2. under applied load of 70 N in acidic *** new grade steel （containing anti-corrosion elements of Cr and rare earth） can find wide application in marine engineering,with further enhanced comprehensive properties via melting process improvement.

关键词： abrasive resistance carbide-free bainite marine steel mechanical performance heat treatment

simple geometrical explanation of Gurtin-Murdoch model of surface elasticity with clarification of its related versions

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science China(Physics,Mechanics & Astronomy) 2010年第3期53卷 536-544页

作者： Ru C. Q. department of mechanical {2., university of Alberta, Edmonton, Alberta, Canada T6G 2.8 1. department of mechanical {2. University of Alberta Edmonton Alberta Canada T6G 2G8

It is showed that all equations of the linearized Gurtin-Murdoch model of surface elasticity can be derived, in a straightforward way, from a simple second-order expression for the ratio of deformed surface area to initial surface area. This elementary derivation offers a simple explanation for all unique features of the model and its simplified/modified versions, and helps to clarify some misunderstandings of the model already occurring in the literature. Finally, it is demonstrated that, because the Gurtin-Murdoch model is based on a hybrid formulation combining linearized deformation of bulk material with 2.d-order finite deformation of the surface, caution is needed when the original form of this model is applied to bending deformation of thin-walled elastic structures with surface stress.

关键词： surface elasticity surface stress Gurtin-Murdoch model

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 science and engineering Huazhong University of Science and Technology department of mechanical {2. 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 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

Analytical and numerical modeling of resonant piezoelectric devices in China-A review

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science China(Physics,Mechanics & Astronomy) 2008年第12期51卷 1775-1807页

作者： YANG Jiashi1,2. & YANG ZengTao1 1 Institute of Mechanics and sensing Technology, school of Civil engineering and Architecture, Central south university, Changsha 410083, China {2. of engineering Mechanics, university of Nebraska, Lincoln, NE 68588-052., UsA 1. Institute of Mechanics and sensing Technology School of Civil Engineering and Architecture Central South University Changsha 410083 China 2. department of engineering Mechanics University of Nebraska Lincoln NE 68588-0526 USA

The results on theoretical and numerical modeling of resonant piezoelectric devices in China are reviewed. solutions to dynamic problems of the propagation of bulk acoustic waves (BAW), surface acoustic waves (sAW), vibrations of finite bodies, and analyses of specific devices are discussed. Results from both the ultrasonics community and mechanics researchers are included. It is hoped that the paper will be useful for the understanding, communication and collaboration between Chinese and foreign scholars. The paper may also be helpful for bridging the gap between ultrasonics and mechanics researchers on piezoelectricity re- search. The paper contains 316 references.

关键词： piezoelectricity wave vibration transducer resonator

Robust H-infinity fuzzy control for uncertain Markovian jump nonlinear singular systems with wiener process

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控制理论与应用（英文版） 2010年第2期8卷 205-210页

作者： Aiqing ZHANG 1 , Huajing FANG 2.(1.College of Mathematics and Computer science, Jianghan university, Wuhan Hubei 430056, China 2.department of Control science and {2., Huazhong university of science and Technology, Wuhan Hubei 430074, China) College of Mathematics and Computer science Jianghan University Wuhan Hubei China department of Control science and engineering Huazhong University of Science and Technology Wuhan Hubei China

This paper deals with the problems of robust stochastic stabilization and H-infinity control for Markovian jump nonlinear singular systems with Wiener process via a fuzzy-control approach. The Takagi-sugeno (T-s) fuzzy model is employed to represent a nonlinear singular system. The purpose of the robust stochastic stabilization problem is to design a state feedback fuzzy controller such that the closed-loop fuzzy system is robustly stochastically stable for all admissible uncertainties. In the robust H-infinity control problem, in addition to the stochastic stability requirement, a prescribed performance is required to be achieved. Linear matrix inequality (LMI) sufficient conditions are developed to solve these problems, respectively. The expressions of desired state feedback fuzzy controllers are given. Finally, a numerical simulation is given to illustrate the effectiveness of the proposed method.

关键词： Fuzzy control H-infinity control singular systems stochastic stability Linear matrix inequality (LMI)

Effects of NaNbO_3-Co_2._3 Co-additive on the Properties of PZN-PZT Ceramics

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Journal of Wuhan university of Technology(Materials science) 2007年第4期22卷 722-724页

作者：邓毅华 College of Material science and engineering South China University of Technology department of Electronic science and Technology Huazhong University of Science and TechnologyWuhan 430074China

NaNbO3-Co2.3 co-added PZN-PZT （PZCNNT） ceramics were prepared using conventional solid state reaction. The piezoelectric and dielectric properties were measured. The experimental results show that the addition of 0.3mo1% Co2.3 leads to low dielectric loss （tgδ） in PZCNNT ceramics and the proper addition of NaNbO3 not only improves piezoelectric properties but also decreases intensively dielectric loss and mechanical loss. The optimal ceramic having d33=310 pC/N, kp=0.59, εr=985, tgδ=0.0034, Qm=1380 was obtained.

关键词： PZN-PZT piezoelectric constant dielectric constant dielectric loss

Dissolution theory of gold in alkaline thiourea solution(Ⅲ) ——Thermodynamics on dissolution of gold in alkaline thiourea solution containing Na _2.O_3

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中国有色金属学会会刊：英文版 1999年第3期9卷 646-650页

作者： Chai Liyuan(柴立元) 1, Masazumi Okido 2.1. department of Nonferrous Metallurgy, Central south university of Technology, Changsha 410083, P.R.China 2. Center for Integrated Research of science and {2., Nagoya university,Nagoya 464, Japan 中南工业大学有色冶金系湖南长沙 Nagoya university 日本

The oxidants of gold were investigated in an alkaline thiourea solution containing Na 2.O 3, in which Na 2. 2. 8 is a proper oxidant for dissolving gold because of in such homogeneous sulfur system coexisting complex agent, oxidant and stabilizing agent. The thermodynamic analyses were conducted on the dissolving of gold in the alkaline thiourea solution containing Na 2.O 3 by the oxidants oxygen or Na 2. 2. 8. The results show that the possibility of gold dissolution reduces with increasing pH value, while oxygen acts as oxidant; and when Na 2. 2. 8 acts as the oxidant of gold in the alkaline thiourea solution of pH 12.5, decomposition potential of thiourea decreases from the standard value 0.42.V to -0.32.V, also the dissolution trend of gold enhances with shifting the mix potential of the solution to the positive direction.

关键词： thermodynamic analysis gold dissolution thiourea leaching Document code:A

ALGORITHMs FOR IMPLEMENTATION OF GENERAL LIMIT REPREsENTATIONs OF GENERALIZED INVERsEs

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Journal of Computational Mathematics 2001年第6期19卷 561-570页

作者： Predarg s. stanimirovic (university of Nis, Faculty of science, department of Mathematics, Cirila i Metodija 2. 18000 Nis, Yugoslavia ) university of Nis 南斯拉夫

Investigates three various algorithms for computation and implementation of general limit representations of generalized inverses. Introduction and preliminaries; Details of the generalized imbedding method; Limit rep... 详细信息

关键词： Generalized inverses Limit representation Finite algorithm Imbedding method.

Electrical Conductivity of the Carbon Fiber Conductive Concrete

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Journal of Wuhan university of Technology(Materials science) 2007年第2期22卷 346-349页

作者：侯作富李卓球 school of sciences Wuhan University of Technology

This paper discussed two methods to enhance the electrical conductivity of the carbon fiber（CF） electrically conductive concrete. The increase in the content of stone and the amount of water used to dissolve the methylcellulose and marinate the carbon fibers can decrease the electrical resistivity of the electrically conductive concrete effectively. Based on these two methods, the minimum CF content of the CF electrically conductive concrete for deicing or snow-melting application and the optimal ratio of the amount of water to dissolve the methylcellulose and marinate the carbon fibers were obtained.

关键词： carbon fiber electrical resistivity conductive concrete