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On Co-precipation Fabrication of Continuously Graded Composites

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Journal of wuhan university of technology(Materials Science) 2002年第3期17卷 17-20页

作者：杨中民 StateKeyLab.ofAdvancedTecnologyforMaterialsSynthesisandProcessing WuhanUniversityofTecnologyWuhan430070China.Email：Yangzm@***

The manner by which the particles settle in the laminar flow region is first described and the characteristics of co sedimentation of two species particles are *** subsequent introduction is focused on the fabrication process of continuously graded composites using co sedimentation ***,the authors point out the key problem that should be solved immediately,based on their current work.

关键词： co sedimentation composites fabrication continuously graded composition

Detection of bursts in neuronal spike trains by the mean inter-spike interval method

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Progress in Natural Science:Materials International 2009年第2期19卷 229-235页

作者： Lin Chena,b,Yong Deng c,Weihua Luo a,Zhen Wang a,Shaoqun Zenga,a Hubei Bioinformatics and Molecular Imaging Key Laboratory,Huazhong university of Science and technology,wuhan 43.074,{3. b college of Mechanical Engineering,Guangxi university,Nanning,53.004,{3. c college of Optoelectronic Science of Engineering,Huazhong university of Science and technology,wuhan 43.074,{3. [a]Hubei Bioinformatics and Molecular Imaging Key Laboratory Huazhong University of Science and Technology Wuhan 430074 China [b]College of Mechanical Engineering Guangxi University Nanning 530004 China [c]College of Optoelectronic Science of Engineering Huazhong University of Science and Technology Wuhan 430074 China

Bursts are electrical spikes firing with a high frequency,which are the most important property in synaptic plasticity and information processing in the central nervous system. However,bursts are difficult to identify because bursting activities or patterns vary with phys-iological conditions or external stimuli. In this paper,a simple method automatically to detect bursts in spike trains is described. This method auto-adaptively sets a parameter (mean inter-spike interval) according to intrinsic properties of the detected burst spike trains,without any arbitrary choices or any operator judgment. When the mean value of several successive inter-spike intervals is not larger than the parameter,a burst is identified. By this method,bursts can be automatically extracted from different bursting patterns of cultured neurons on multi-electrode arrays,as accurately as by visual inspection. Furthermore,significant changes of burst variables caused by electrical stimulus have been found in spontaneous activity of neuronal network. These suggest that the mean inter-spike interval method is robust for detecting changes in burst patterns and characteristics induced by environmental alterations.

关键词： Inter-spike interval Bursts Spike trains Multi-electrode arrays

1/2 SUBHARMONIC RESONANCE OF A SHAFT WITH UNSYMMETRICAL STIFFNESS

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Chinese Journal of Mechanical Engineering 2003年第1期16卷 25-27,30页

作者： Xiao XiwuYang Shuzi Huang YuyingDepartment of Mechanics,Huazhong university of Scienceand technology,wuhan 43.074, {3. Department of Mechanics Huzahong University of Scienceand Technology Wuhan 430074

The 1/2 subharmonic resonance of a shaft with unsymmetrical stiffness is studied. By means of the Hamilton's principle the nonlinear differential equations of motion of the rotating shaft are derived in the rotating rectangular coordinate system. Transforming the equations of motion from rotating coordinate system into stationary coordinate system and introducing a complex variable, the equation of motion in complex variable form is obtained, in which the stiffness coefficient varies periodically with time. It presents a nonlinear oscillation system under parametric excitation. By applying the method of multiple scales (MMS) the averaged equation, the bifurcating response equations and local bifurcating set are obtained. Via the theory of singularity, the stability of constant solutions is analyzed and bifurcating response curves are obtained. This study shows that the rotating shaft has rich bifurcation phenomena.

关键词： Shaft with unsymmetrical stiffiless Subharmonic resonance Stability Bifurcation MMS

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 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 1 523.1 573.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

Studies on Wear and Corrosion Resistances of Carbon Nitride Thin Films on Ti Alloy

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wuhan university Journal of Natural Sciences 2003年第3A期8卷 821-824页

作者： Li Jin\|chai, Guo Huai\|xi, Lu Xian\|feng, Zhang Zhi\|hong, Ye Ming\|sheng School of physics and technology, wuhan university, {3. 4.0072. Hubei, china wuhan university School of Physics and Technology Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

CN x /SiCN composite films were prepared on titanium ( Ti ) alloy substrates by Radio Frequency Plasma Enhanced Chemical Vapor Deposition ( RF\|PECVD ). As a buffer layer, SiCN ensured the adhesion of the CN x thin films on Ti substrates. X\|ray diffraction ( XRD) measurement revealed that the composite films possessed α\|C 3. N 4 structure. The microhardness of the films was 48 to 50 GPa. In order to test the characteristics of wear and corrosion resistances, we prepared Ti alloy samples with and without CN x /SiCN composite films. Also for strengthening the effect of wear and corrosion, the wear tests were carried out under high load (12 MPa) and in 0.9% NaCl solution. Results of the wear tests and the corrosive electrochemical measurements showed that the samples coated with CN x films had excellent characteristics of wear and corrosion resistances compared with Ti alloy substrate samples.

关键词： carbon nitride films RF PECVD wear resistance corrosion resistance

Positive Periodic Solution for a Nonautonomous Delay Differential Equation

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Acta Mathematicae Applicatae Sinica 2003年第2期19卷 307-316页

作者： Bing LiuDepartment of Mathematics, Huazhong university of Science and technology, wuhan 43.074, {3. Department of Mathematics Huazhong University of Science and Technology Wuhan 430074 China

Abstract In this paper, by using the Krasnoselskii fixed point theorem, we study the existence of one or multiple positive periodic solutions of a nonautonomous delay differential equation. We also give some examples ... 详细信息

关键词： Positive periodic solution delay differential equation Krsnoselskii fix point theorem

Microscopic Calculation of Parameters of the sdg Interacting Boson Model for ^(104-110)Pd Isotopes

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Chinese journal of nuclear physics 1995年第3期17卷 194-199页

作者： Liu Yong~1 Shi Zhu-yi~2 Dan Han-jou~3.Sang Jian-ping~41 Institute of Particle physics,Huazhong Normal university,wuhan 43.0702 Department of physics,Guizhou Institute for Nationalities,Guiyang 5500253.Department of physics,Xianning Teacher’s college,Xianning 43.0004 Department of physics,wuhan university,wuhan 4.0072 华中师范大学粒子物理所湖北武汉贵州民族学院物理系贵州贵阳 550025 咸宁师范高等专科学校物理系湖北咸宁 437000 武汉大学物理系湖北武汉

The parameters of the sdg interacting boson model Hamiltonian are calculated for the 104-110*** calculations utilize the microscopic procedure based on the Dyson boson mapping proposedby Yang-Liu-Qi and extended to include the g boson *** calculated parameters reproduce thosevalues from the phenomenological *** resulting spectra are compared with the experimental spectra.

关键词： sdg interacting boson model Dyson boson mapping Microscopic investigation

Preparation of Filling Porous Osteoconduction Materials and Its Animal Experiment Study

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Journal of wuhan university of technology(Materials Science) 2011年第2期26卷 232-235页

作者：陈晓明 Biomedical Materials and Engineering Research Center Wuhan University of Technology

Titanium rods were processed into implant samples with cavity and groove in which was filled with HAP/β-TCP porous osteoconduction composite materials in order to increase the mechanical stability of the implant in *** phase compositions of the composite was characterized by X-ray diffraction （XRD） and scanning electron microscopy（SEM）.Histological evaluation showed that the biogradable composite could enhanced the ability of new bone *** composite can conduct new bone tissue growing into the cavities gradually after implanted into animal,and then achieve mechanical *** filling biogradable compound exhibited excellent biocompatibility,which combined with the new bone tissues tightly without inflammation and loosing.

关键词： β-tricalcium phosphate hydroxyapate filling osteoconduction titanium animal experiment

Effect of Preparation Atmosphere on the Structure and Properties of Vanadium Pentoxide Xerogel Films

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Journal of Materials Science & technology 2004年第3期20卷 365-367页

作者： Wen CHEN Manzhu KB Qing XU Quanyao ZHU Liqiang MAI Li LI School of Materials Science and Engineering, wuhan university of technology,wuhan 43.070, {3. Sch. of Mat. Sci. and Eng. Wuhan Univ. of Technol. Wuhan 430070 China

In this article, the vanadium pentoxide sols are synthesized by two different routes (melted and quenched in oxygenatmosphere or in air). The structure and properties of the vanadium pentoxide xerogel films are characterized byXRD, ESR, cyclic voltammograms curves and UV-visible transmittance analysis. The results show that the sampleprepared in oxygen has poorer crystallization. lower content of V^(4+) ions and higher Li^+ insertion capacity comparedwith that prepared in air.

关键词： Preparation atmosphere V_2O_5 Structure Properties