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Damping Properties of Flexible Epoxy Resin

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Journal of wuhan university of technology(Materials science) 2008年第3期23卷 411-414页

作者：王翔刘韩星 school of Materials science and Engineering Wuhan University of Technology State Key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of Technology

Amino-terminated polyethers and amino-terminated polyurethane were used as curing agent to cure the epoxy resin together and get a series of cured products. The damping properties of the composites were studied by DMA test at different measurement frequencies. Damping mechanical tests show that the flexible epoxy resin has higher loss factor than common epoxy. The highest loss factor reaches 1.57. Also the height and position of loss factor peak of the flexible epoxy resin varies by changing the content of amino-terminated polyethers. Results shows that the flexible epoxy resin can be used as damping polymer materials at room temperature or in common frequency range.

关键词： flexible epoxy damping properties amino-terminated polyethers amino-terminated polyurethane

Fractal Analysis of Gas Diffusion Layer in PEM Fuel Cells

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Journal of wuhan university of technology(Materials science) 2006年第1期21卷 22-25页

作者：石英肖金生 State Key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070ChinaSchool of Automation Wuhan University of Technology Wuhan 430070 China State Key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070ChinaSchool of Automotive EngineeringWuhan University of Technology Wuhan 430070China

The aim of this study is to show how fractal analysis can be effectively used to characterize the texture of porous solids. The materials under study were carbon papers, the backing material of the gas diffusion layer （GDL） in Proton Exchange Membrane Fuel Cell （PEMFC）. The fractal dimensions were calculated by analyzing data from mercury porosimetry. The polytotrafluoroethylene （PTFE） treated carbon paper shows a significantly high fractal dimension value than pare sample, and the high fractal dimension signifies that the physical complexity of the pore surface is enhanced. The fractal dimension can be used as a valid parameter to monitor the textural evolution of the samples as the treatment progresses, as this behaves in a similar way to other textural parameters. The use of fractal analysis in conjunction with the results of classical characterization methods leads to a better understanding of textural modificatious in the processing of materials.

关键词： PEMFC gas diffusion layer fractal dimension mewury porosimetry

THEORETICAL DESIGN AND MOTION PLANNING OF NONHOLONOMIC MANIPULATOR

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Chinese Journal of Mechanical Engineering 2004年第2期17卷 222-225页

作者： Tan Yuegang Deng Yuhui WU Zhengping school of Mechanical and Electronic Engineering,wuhan university of technology,wuhan 430070, china Department of science and technology Studies University College London WC1E 6BT UK school of Mechanical and Electronic Engineering Wuhan University of Technology Wuhan 430070 China

A new nonholonomic transmission mechanism is proposed based on thenonholonomic theory and nonlinear control principle, and combined with conditions of thenonholonomic motion planning and control, that is researched to compose method of the motiontransfer chain from this transmission mechanism, on which a new nonholonomic manipulator isdesigned. This nonholonomic manipulator is a controllable multi-joint manipulator that actuated onlyby two-servo electromotor. Its motion expresses the characteristic of nonholonomy constraint andnonlinear, and that also satisfies the chained form convertibility. And then, using the nonlinearcontrol principle of chained system, motion characteristic of the nonholonomic manipulator isapplied. From simulation verification and analysis, the usefulness of the theoretical design andcontrol strategies is shown, and that is important in design and research of handiness robot andmulti-finger robot hand.

关键词： Nonholonomic system Nonholonomic motion planning Nonlinear controlMulti-joint Manipulator

Characteristics and Microstructure of Graphite Encapsulated Iron Nanoparticles

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Journal of wuhan university of technology(Materials science) 2007年第2期22卷 214-217页

作者：曹宏 school of Materials science&Engineering Wuhan Institute of Technology

The graphite encapsulated a-Fe particles were prepared by reduction of stage-2 and stage-3 FeCI3 graphite intercalation compounds （GICs） with metallic potassium, X-ray diffraction analysis （XRD）, energy dispersive X-ray spectroscopy （EDS） investigation and transmission electron microscopy （TEM） observation show that the reduction products of stage-2 FeCl3-GICs contains more abundant a-Fe nanoparticles than those of stage-3. High-resolution TEM （HRTEM） observation reveals that the nanoparticle of a-Fe was polycrystals or twins, which was real or quasi two-dimension in shape, and whose space orientation was strictly controlled by the graphene. Based on the experiment results, a possible growth model of the graphite encapsulated ct-Fe was proposed.

关键词： encapsulated nanoparticle graphite intercalation compounds iron electron transmissionmicroscopy (TEM) template

Synthesis, Characterization and Flame-retardant Properties of Epoxy Resins and AACHH Composites

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Journal of wuhan university of technology(Materials science) 2009年第5期24卷 763-767页

作者：秦麟卿 State Key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of Technology

Flame retardant epoxy resins were prepared by a simple mixed method using ammonium aluminum carbonate hydroxy hydrate （AACHH） as a halogen-free flame retardant. The prepared samples were characterized by X-ray diffraction, thermogravimetric and differential scanning calorimetry, scanning electron microscope and limiting oxygen index（LOI） experiments. Effects of AACHH content on LOI of epoxy resins/AACHH composite and flame retardant mechanism were investigated and discussed. Results show that AACHH exhibites excellent flame-retardant properties in epoxy resin（EP）. When the content of AACHH was 47.4%, the LOI of EP reached 32.2%. Moreover, the initial and terminal decomposition temperature of EP increased by 48 ℃ and 40 ℃, respectively. The flame retarded mechanism of AACHH is due to the synergic flame retardant effects of diluting, cooling, decomposition resisting and obstructing.

关键词： epoxy resin(EP) flame retardant ammonium aluminum carbonate hydroxy hydrate (AACHH) composite

Effect of Tin on the Reaction Synthesis of Ternary Carbide Ti_3AlC_2

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Journal of wuhan university of technology(Materials science) 2009年第2期24卷 283-286页

作者：周卫兵 school of Materials science and Engineering Wuhan University of Technology

The effect of tin on synthesis of Ti3AlC2 by spark plasma sintering （SPS） from TiC/Ti/Al powders was investigated. X-ray diffraction （XRD） and scanning electron microscopy （SEM） were used for phase identification and microstructure evaluation. The experimental results show that addition of tin can considerably accelerate the synthesis reaction of Ti3AlC2 and fully dense, essentially single-phase polycrystalline Ti3AlC2 could be successfully obtained by sintering 2TiC/1Ti/1Al/0.2Sn powders at 1200-1250 ℃ under a pressure of 30 MPa. SEM images show that Ti3AlC2 samples in about 2-5 μm thick and 10-25μm long platelets can be obtained. The fracture toughness and flexural strength of Ti3AlC2 were 6.5±0.2 MPa·m^1/2 and 560±10 MPa, respectively.

关键词： titanium aluminum carbide spark sintering technique synthesis

Preparation and Characterization of Polylactide/Montmorillonite Nanocomposites

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Journal of wuhan university of technology(Materials science) 2009年第4期24卷 562-565页

作者：吴选军 school of Chemical Engineering Wuhan University of Technology

The montmorillonite, a form of layered silicate, was successfully intercalated into polylactide （PLA） matrix through solvent-casting technique. In addition, PLA/MMT nanocomposite films were produced, in which homogenous distribution of the silicate lamellae plays a key role in the mechanical properties of the films. A small amount（5wt%） of OMMT intercalated into the PLA matrix resulted in their flexibility enhancement, from 3.68%（pure PLA film） to 352.65%. The results of wide-angle X-ray diffraction （WAXD） patterns confirmed that the silicate interlayer distance increased from 3.044 nm （for OMMT） to 3.56nm （for 5wt%, maximum） with increasing OMMT contents, but decreased to 3.319 nm when OMMT content was over 8wt%. FT-IR also verified the molecular-level associations between PLA chains and OMMT lamellae by vibration variances of hydrogen bonding. DSC thermograms demonstrated that thermal stabilities of the nanocomposite films enhanced, due to the silicate lamellae dispersed into PLA matrix.

关键词： polylactide montmorillonite nanocomposite characterization thermo-mechanic at property

Preparation and Absorption/Desorption Performance of Gypsum-based Humidity Controlling Materials

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Journal of wuhan university of technology(Materials science) 2011年第4期26卷 684-686页

作者：姜洪义 school of Materials science and Engineering Wuhan University of Technology

Absorption/desorption properties of some humidity controlling materials which contain gypsum as basic cement materials and activated Sepiolite powder as humidity controlling media were tested. The kinetics curve of moisture adsorption/desorption were drawn and humidity controlling performance in nature environment was verified. The experimental results show that moisture absorption/desorption rates are increased, and the speed is also accelerated. These materials, which can adjust environmental humidity effectively, are new ones with good humidity controlling performance.

关键词： activated Sepiolite gypsum-composites humidity controlling performance

Electronic Structure and Thermoelectric Properties of Na and Ni-doped Ca_3Co_2O_6

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Journal of wuhan university of technology(Materials science) 2006年第3期21卷 94-96页

作者：闵新民 Department of Applied Chemistry Wuhan University of Technology Wuhan 430070 ChinaState Key Laboratory of Advanced Technology for Materials Synthesis and ProcessingWuhan University of Technology Wuhan 430070China

The electronic structures of Ca3Co2O6, Na and Ni doped models were studied by the quantum chemical software of Cambride Serial Total Energy Package （CASTEP） that is based on deusity function theory （DFT） and psendo-potential. The electronic conductivity, seebeck coefficient, thermal conduetivity and figure of merit （Z） were computed. The energy band structure reveals the form of the impurity levels due to the substitutional imapurity in semiconductors. Na-doped model stunts the character of p-type semiconductor, but Xi-doped model is n-type semiconductor. The calculation results show that the electric conduetirity of the doped model is higher than that of the non-doped model, while the Seebeck coefficient and thermal conductivity of the doped model are lower than those of the non-doped one. Because of the great increase of the electric conductivity, Z of Na- doped model is enhanced and thermoelectric properties are improved. On the other hand, as the large decline of Seebeck coefficient, Z of Ni-doped model is less than that of the non-doped model.

关键词： cobalt oxide substitutional impurity quantum chemical calculation electronic structure thermoelectric property