检索结果-南通市图书馆

HCWCI/Carbon Steel Bimetal Liner by Liquid-Liquid Compound Lost Foam Casting

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第10期19卷 13-19页

作者： XIAO Xiao-feng1,2, YE Sheng-ping2, YIN Wei-xin3. XUE Qiong4 (1. School of mechanical engineering and Automation, wuhan Textile {3., wuhan 43.073. hubei, china 2. State Key Laboratory of Material Processing and Die and Mould technology, Huazhong {3. of Science and technology, wuhan 43.074, hubei, china 3. wuhan Zhike Abrasive-Resistant Material Science and technology Development Co Ltd, wuhan 43.073. hubei, china 4. college of Science, wuhan {3. of technology, wuhan 43.079, hubei, china) [a] School of mechanical engineering and Automation Wuhan Textile University Wuhan 430073 Hubei China [b] State Key Laboratory of Material Processing and Die and Mould technology Huazhong University of Science and Technology Wuhan 430074 Hubei China [c] wuhan Zhike Abrasive-Resistant Material Science and technology Development Co Ltd Wuhan 430073 Hubei China [d] college of Science Wuhan University of Technology Wuhan 430079 Hubei China

Impact, friction and corrosion from the grinding balls and the grinding medium during the mineral processing result in liner breakage. Liner, made from Hadfield steel or alloyed steel, could not have served in wet grinding environment for more than ten months. Composite liner, made from HCWCI (high Cr white cast iron) and carbon steel, has been developed successfully with liquid-liquid composing process based on LFC (lost foam casting). The microstructure of composite was analyzed with optical microscope, SEM (scanning electron microscope)/EDX energy-dispersive X-ray and XRD (X-ray diffraction). According to micrograph, the combination region of two metals was staggered like dogtooth, no mixtures occurred between two liquid metals, and its interface presented excellent metallurgical bonding state. The results of mechanical property test show that, the hardness of HRC, the fracture toughness, and the bending strength are more than 61, 16.5 J/cm2 and 1 600 MPa, respectively. Comparison between liners made from bimetal composite and alloyed steel has also been investigated in industrial hematite ball mill. The results of eight months test in wet grinding environment prove that the service life of bimetal composite liner is three times as long as that of one made from alloyed steel.

关键词： composite liner bimetal liquid-liquid compound composite interface lost foam casting high Cr white cast iron

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

在线全文

学校读者我要写书评

暂无评论

Journal of wuhan university of technology(Materials Science) 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

METHOD TO SOLVE ELASTIC CONJUGATE SURFACES IN MULTI-TEETH MESHING

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of mechanical engineering 2002年第4期15卷 348-352页

作者： Yi ChuanyunSchool of mechanical Science and engineering, Huazhong university of Science and {3.,wuhan 43.074, china School of mechanical Science and engineering Huazhong University of Science and Technology Wuhan 430074

A method to solve the elastic conjugate surfaces in multi-teeth meshing ispresented. In mechanical manufacturing and design, there exist a lot of problems relating toconjugate surfaces, such as three-dimensional engagement, steel rolling and workpiece machining,which cause great effects on the quality of machining and performances of transmission. This methoddescribes relation between conjugate motion and elastic deformation in the process of mesh-in andmesh-out, and can be used to determine the profile of gear tooth by a certain given load sharing.

关键词： multi-teeth meshing elastic conjugate surfaces

NOVEL FORMULATION OF STATIC STABILITY FOR A WALKING QUADRUPED ROBOT

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of mechanical engineering 2003年第2期16卷 120-122页

作者： Chen XuedongSchool of mechanical Scienceand engineering,Huazhong university of Scienceand {3.,wuhan 43.074, china School of mechanical Science and engineering Huazhong University of Science and Technology Wuhan 430074 China

By defining the static stable area for foot placement, a new approach toanalysis of quadruped robot stability is presented. Unlike conventionally, the method avoids solvingcomplicated direct kinematics of quadruped robot and shows the information on the robot stabilityand the selection of swing leg. Especially, the proposed algorithm can be used as real-timeoperation for on-line gait generation and control for quadruped robots. The effectiveness of theproposed approach is shown through a practical crawling experiment of the quadruped robotTITAN-VIII.

关键词： quadruped robot static stability gait generation

Preparation and Characterization of Chitosan/Carboxymethylated Konjac Glucomannan Blend Films

在线全文

学校读者我要写书评

暂无评论

wuhan university Journal of Natural Sciences 2002年第1期7卷 107-112页

作者： Zheng Hua 1 , Du Yu-min 2 1. Department of Chemical engineering, wuhan university of {3., wuhan 43.070, hubei, china 2. college of Chemistry and Molecular Sciences, wuhan university, wuhan 43.072, hubei, china wuhan university of technology Department of Chemical Engineering Wuhan Hubei China (GRID:grid.162110.5) (ISNI:***) wuhan university College of Chemistry and Molecular Sciences Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

In order to improve the mechanical and water swelling properties of the chitosan (CS) film, a series of transparent films were prepared by blending 2%(weight) chitosan acetic acid solution with 1.5%(weight) carboxymethylated konjac glucomannan (CMKGM) aqueous solution according to predetermined ratio and drying at 3.°C. The morphological structure, miscibility, thermal stability, mechanical properies, and swelling capacity of the blend films were studied by infrared (IR), X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron micrograph (SEM), and measurements of the mechanical properties and swelling properties. The results demonstrated that there was strong interaction and good miscibility between CS and CMKGM resulted from intermolecular hydrogen bonding and electrostatic force. The mechanical properties in dry state and wet state, thermostability, and water swelling properties of the blend films were obviously improved. The best values of the tensile strength in the dry and wet state achieved 89 MPa and 49 MPa, respectively, when the CMKGM content was 3.%(weight). The CS/ CMKGM blend films provided promising biomedical applications.

关键词： Key words chitosan carboxymethylated konjac glucomannan blend films structure characterization

Ferroelectric properties of Bi_(3.4)Ho_(0.6)Ti_3._(12) thin films prepared by sol-gel method

在线全文

学校读者我要写书评

暂无评论

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 technology, wuhan university of technology, wuhan 43.070, china 2 School of mechanical engineering, Chongqing university of Science and technology, Chongqing 400050, china 3.Department of Physics, wuhan university, wuhan 43.072, china School of Materials Science and technology Wuhan University of Technology Wuhan 430070 China School of mechanical engineering 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 (Bi3.4Ho0.6Ti3.12, 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 2Pr and 2Ec of the 600-nm-thick BHT film were 3..4 μC/cm2 and 3.6.1 kV/cm, respectively at applied electric field 500 kV/cm. The dielectric constant and dielectric loss are about 3.0 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： Bi3.4Ho0.6Ti3.12 thin film sol-gel method ferroelectric property fatigue dielectric constant

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

在线全文

学校读者我要写书评

暂无评论

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,{3. 43.074,china b college of mechanical engineering,Guangxi university,Nanning,53.004,china c college of Optoelectronic Science of engineering,Huazhong university of Science and technology,{3. 43.074,china [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

FLOW PATTERNS AND FORCE CHARACTERISTICS OF LAMINAR FLOW PAST FOUR CYLINDERS IN DIAMOND ARRANGEMENT

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2011年第1期23卷 55-64页

作者： ZOU Lin LIN Yu-feng LU Hong School of mechanical and Electronic engineering Wuhan University of Technology Wuhan 430070 China Department of mechanical engineering The Hong Kong Polytechnic University Hong Kong China

A three-dimensional numerical investigation of cross-flow past four circular cylinders in a diamond arrangement at Reynolds number of 200 is carried *** the spacing ratios（L /D）ranging from 1.2 to 5.0,the flow patterns can be classified into three basic *** critical spacing ratio for the transition from narrow gap flow pattern to vortex impingement flow pattern around the cylinders is found to beL /D=3.0,while a single bluff-body flow pattern is observed atL /D=*** relationship between the three-dimensional flow patterns and force characteristics around the four cylinders shows that the variation of forces and Strouhal numbers againstL /D are generally governed by these three kinds of flow *** is concluded that the spacing ratio has important effects on the development of the free shear layers about the cylinders and hence has significant effects on the force and pressure characteristics of the four cylinders with different spacing ratios.

关键词： four cylinders spacing ratio flow pattern force characteristics

Microstructure and Properties of Low Temperature Composite Chromized Layer on H13.Tool Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 2005年第2期21卷 251-255页

作者： Cuilan WU, Chengping LUO and Ganfeng ZOU college of mechanical engineering, South{3. university of technology, Guangzhou 510641,{3. Coll. of Mech. Eng. South China Univ. of Technol. Guangzhou 510641 China

Low temperature composite chromizing is a process composed of a plain ion-carbonitriding or ion-nitriding at 550-580℃, followed by a low-temperature chromizing in a salt-bath of 590℃. The microstructure and properties of the low temperature composite chromized layer on H13.tool steel were investigated using metallography, X-ray diffraction, microanalysis, hardness and wear tests. It was found that this low temperature process was thermo-dynamically and kinetically possible, and the composite chromized layer on H13.steel, with a thickness of 3.6 μm, consisted of three sub-layers (bands), viz. the outer Cr-rich one, the intermediate (black) one, and the inner, original white layer. After chromizing, the former diffusion layer was thickened. The results of X-ray diffraction showed that the composite chromized layer contained such nitrides and carbides of chromium as CrN, Cr2N, (Cr, Fe)23.6, and (Cr, Fe)7C3. as well as plain α-(Fe, Cr). A high surface microhardness of 1450-1550 HV0.025, which is much higher than that obtained by the conventional ion carbonitriding and ion nitriding, was obtained. In addition, an excellent wear resistance was gained on the composite chromized layer.

关键词： H13.tool steel Low temperature composite chromizing Nitride and carbide of chromium Microhardness Wear resistance