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Effects of Plasma Nitriding on microstructure and Tribological Properties of CoCrMo Alloy Implant materials

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Journal of Bionic engineering 2010年第4期7卷 337-344页

作者： Qingliang Wang,Lei Zhang,Jiandong Dong School of material science and engineering,china university of Mining & Technology,Xuzhou 221116,P.R.china School of material science and engineering China University of Mining & Technology Xuzhou P. R. China

Medical forged CoCrMo alloy was treated by plasma nitriding *** microstructures were characterized by 3Dprofiler,SEM and *** tribological properties were investigated under lubrication of 25% bovine serum *** that plasma nitriding is a promising process to produce thick,hard,and more wear resistant layers on the surface of *** nitrided samples showed an important increase in the surface hardness due to the formation of harder CrN andCrN phases with compact nano-crystalline *** typical hardness values of HVincreased almost two times thanuntreated *** bovine serum lubrication,at low nitriding temperature the Coefficient of Friction (COF) of nitrided samplewas lower than that of untreated sample,but at high nitriding temperature the COF was almost the same as the untreated *** with the untreated sample,the nitrided samples showed lower wear rates and higher wear resistance under differentnitriding *** adhesive wear is the main mechanism for untreated CoCrMo alloy and the wear mechanisms ofnitrided ones are the fatigue wear and slight adhesive *** is concluded that the improvement of wear resistance is ascribed tothe hard nitride formation of CrN and CrN phases at the nitrided surfaces.

关键词： CoCrMo alloy plasma nitriding microstructure friction and wear

microstructure Characteristics and Apparent Viscosity of Hypereutectic Al-24%Si Alloy Melt During Semi-solid state Stirring

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Journal of university of science and Technology Beijing 2001年第2期8卷 126-128页

作者： Yanjun Li, Weimin Mao, Zisheng Zhen, Xueyou Zhong (material science and engineering School, university of science and Technology Beijing, Beijing 100083, china) material Sci. and engineering School University of Science and Technology Beijing 100083 China

The microstructural evolution and apparent viscosity of hypereutectic Al-24%Si alloy during semi-solid state shearing were studied with a Searte type viscometer. When the alloy melt was continuously stirred from 720 degreesC to eutectic temperature, the primary Si crystals were gradually changed from elongated platelets to near-spherical shapes. It was found that some nondendritic a-phase formed when the melt was stirred below 585 degreesC. The experiment showed that the semi-solid stirring had strong effect on inhibiting the anisotropic growth of Si crystals during solidification. The apparent viscosity of the alloy melt increased slowly with the decreasing of temperature before the formation of nondendritic alpha -phase, which caused the dramatic increase of apparent viscosity.

关键词： hypereutectic Al-Si alloy solidification structures apparent viscosity

Optical, structural and photophysical properties of new solid photocatalyst In2GaTaO7

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Optical, structural and photophysical properties of new soli...

Interface-directed sol-gel:direct fabrication of the covalently attached ultraflat inorganic oxide pattern on functionalized plastics

Ⅻ International Symposium on Small Particles and Inorganic Clusters

作者： Jingfei Luan Minghui Lu Shourong Zheng Yanfeng Chendepartment of materials science and engineering & national laboratory of solid state microstructures nanjing university nanjing 210093 P.R.china state Key laboratory of Pollution Control and Resource Reuse School of Environment nanjing university nanjing 210093 P.R.china

＜正＞ Since photoinduced splitting of water on TiO2 electrode was reported, semiconductor photocatalytic process has received much attention. Especially, the scientific interests in the photocatalytic degradation of organic dyes have grown quickly in recent years because about 15% of the total world production of dyes is lost during the dyeing process and is released in

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science china Chemistry 2010年第1期53卷 173-182,287-288页

作者： GAN ShengHua,YANG Peng & YANG WanTai state Key laboratory of Chemical Resource engineering College of materials science and engineering,Beijing university of Chemical Technology,Beijing 100029,china state Key laboratory of Chemical Resource engineering College of materials science and engineering Beijing University of Chemical Technology Beijing China

For plastic electronics and optics,the fabrication of smooth,transparent and stable crack-free inorganic oxide films(and patterning) on flexible polymeric substrates with strong bonding strength and controllable thickness from nanometers to micrometers is a key but still remains a *** versatile inorganic oxides,silica oxide film as SiOx is especially important because this semiconductor material could provide crucial properties in devices or serve as a base layer for further multilayer *** this paper,we describe a new interface-directed sol-gel method to fabricate flexible high quality silicon oxide film onto commodity *** resulting crack-free silica film has strong covalent bonding with polymer substrates,homogeneous morphology with ultralow roughness,highly optical transparency,tunable thickness from nm to μm,and easy patterning *** fabrication strategy relies on a novel photocatalytic oxidation reaction by photosensitive ammonium persulfate(APS),which is able to fabricate highly reactive hydroxyl monolayer surface on inert polymeric *** kind of hydroxylated surface could serve as nucleation and growth sites to initiate surface sol-gel *** a result,well-defined SiOx film deposition(gelation) occurs,and patterned hydroxylation regions could be easily utilized to induce the formation of patterned oxide film *** strategy also excludes the requirements of clean room and vacuum devices so as to fulfill low-cost and fast fabrication *** application examples from such high quality SiOx layer onto plastics are given but should not be limited within *** is that oxygen permeation rate of SiOx deposited polymer film decreases 25 times than pristine polymer substrate,which is good for the potential packaging *** other one is that silanization monolayer,for example,3-aminopropyltriethoxysilane(APTES),could be successfully constructed onto silica layer through classical silanization reac

关键词： surface patterning silicon oxide sol-gel polymer surface modification functional coatings

Investigation on Vibrational Spectra and Structures of 4-Mercaptopyridine Monomer and Its Dihydrate

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Chemical Research in Chinese Universities 2006年第1期22卷 90-93页

作者： CHENG Jian-bo 1,2 , XUE Wei-qing 1 , ZHAO Bing 1** , ZHANG Gang 3 and GONG Bao-an 2 1. Key laboratory for Supramolecular Structure and material of Ministry of Education, Jilin university, Changchun 130012, P. R. china 2. science and engineering College of Chemistry and Biology, Yantai university, Yantai 264005, P. R. china 3. state Key laboratory of Theoretical and Computational Chemistry, Jilin university, Changchun 130023, P. R. china Key laboratory for Supramolecular Structure and material of Ministry of Education Jiln University Changchun 130012 P. R. China science and engineering College of Chemistry and Biology Yantai University Yantai 264005 P. R. China state Key laboratory of Theoretical and Computational Chemistry Jiln University Changchun 130023 P. R. China

The optimized molecular structures and vibrational frequencies of 4-mercaptopyridine(4MPY) monomer and its dihydrate were studied by means of the density functional theory(DFT), viz. B3LYP method with the 6-311++G(d,p) basis set. On the basis of the calculations, the assignments of the vibrational spectra of the monomer and the dihydrate were performed, and so were investigated the changes in the structure and the vibrational spectrum of the dihydrate as well as the intermolecular force resulting in the formation of the dihydrate. The calculated results show that each of the water molecule planes is vertical to the pyridine ring plane in the dihydrate that is formed via the H-bonds between 4MPY and water molecules. Furthermore, the structure and the vibrational spectrum of 4MPY can be consi- derably affected by the water molecules.

关键词： 4MPY Dihydrate Vibrational spectra DFT Molecular structure

Surface roughness and removal rate in magnetorheological finishing of a subsurface damage free surface

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Progress in Natural science:materials International 2005年第6期15卷 538-544页

作者： CHENG Haobo1*, WANG Yingwei2, FENG Zhijing1 and CHENG Kai3(1. state Key laboratory of Tribiology, Tsinghua university, Beijing 100084, china 2. department of material sciences, Changchun university of science and Technology, Changchun 130021, china 3. Faculty of Information and engineering Systems, City Campus, Leeds LS1 3HE, UK) state Key laboratory of Tribiology Tsinghua University Beijing 100084 China department of material sciences Changchun University of Science and Technology Changchun 130021 China Faculty of Information and engineering Systems City Campus Leeds LS1 3HE UK

Based on computer-controlled optical surfacing, a new technique called magnetorheological finishing (MRF), is presented. The new technique combines the features of conventional loose abrasive machining with a wheel shaped polishing tool. The tool incorporates a host of features and has unprecedented fabricating versatility. The pre-polishing and fine polishing processes can be performed only by adjusting different parameters. The material removal function is studied theoretically and the results of simulation present a Gaussian distribution feature. Based on the established theoretical model, material removal rate experiments involving a parabolic mirror are designed and carried out to determine the effect of controllable parameters on size of the gap between the workpiece and the polishing wheel, rotating speed of the polishing wheel, concentration of volume fraction of non-magnetic particles and polishing time. Further experiments are carried out on the surface microstructure of the workpiece, the final surface roughness with an initial value of 10.98 nm reaches 1.22 nm root mean square (RMS) after 20 min of polishing. The subsurface damage experiment and the atomic force microscopy (AFM) measurement on the polished surface can also verify the feasibility of the MRF technique.

关键词： magnetorheological finishing surface roughness computer controlled optical surfacing subsurface damage removal function.

Capacity fading of spinel LiMn_2O_4 during cycling at elevated temperature

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Journal of university of science and Technology Beijing 2002年第3期9卷 197-201页

作者： Yanbin Chen and Qingguo Liulaboratory of solid state Ionics, university of science and Technology Beijing, Beijing 100083, china (Received 2001-09-20) *** laboratory of solid state Ionics University of Science and Technology Beijing Beijing 100083 China

A normal spinel LiMn_2O_4 as cathode material for lithium-ion cells wascycled galvanostatically (0.2 C) at 55 deg C. To determine the contribution of each voltage plateauto the total capacity fading of the cathode upon repeated cycling, the capacities in each plateauwere separated by differentiation of voltage vs. capacity. The results how that the capacity fadingin the upper voltage plateau is more rapidly than that in the lower during discharging, while incharging process, it fades slower than that in the lower voltage range. The increased capacity shiftand aggravated self-discharge/electrolyte oxidation during discharging contribute to a high fadingrate in the upper step. Capacity shift also takes place during charging process, which againenhancing the fading rate of the lower voltage plateau. An increase in capacity shift, as a resultof an increase in polarization of the cell, plays a major role in determining the fading rate ineach voltage plateau, further reflecting the thickening of the passivation layer on the activeparticles, and the accumulation of electrolyte decomposition. The relative capacity loss formodified spinels is well correlated with the relative increase in the polarization of thehalf-cells, confirming the above causes for capacity fade of this kind of cathode material.

关键词： spinel LiMn_2O_4 capacity fading capacity shift self-discharge lithium reinsertion electrolyte oxidation

Magnetic and dielectric properties of low temperature fired ferrite/ceramic composite materials

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Progress in Natural science:materials International 2011年第1期21卷 21-26页

作者： Wei-wei LING~(1,2),Huai-wu ZHANG~1,Ying HE~1,Yuan-xun LI~1,Yun-yan WANG~1 1.state Key laboratory of Electronic Thin Films and Integrated Devices, university of Electronic science and Technology of china,Chengdu 610054,china 2.department of Communication engineering,Chengdu university of Information Technology, Chengdu 610225,china state Key laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China department of Communication engineering Chengdu University of Information Technology

Ni-Cu-Zn ferrite/CaTiO3and Ni-Cu-Zn ferrite/BaTiO3composites which can be applied in low temperature co-fired ceramic（LTCC） technology were synthesized by conventional solid-state reaction at temperature lower than 950℃.Influence of the microstructures and the gap parameterδ/D on the complex permeability of the above two composites was *** modifiedδ/D values of the above two composites show a good fit to the magnetic circuit *** dielectric properties of the composites were predicted by the Maxwell-Garnctt effective medium theory and the discrepancy between measured and calculated values was analyzed.

关键词： ferrite/ceramic composite low temperature co-fired ceramic(LTCC) solid-state reaction magnetic properties dielectric properties

GROWTH AND ELECTRICAL PROPERTIES OF LANIO3/PB(ZR0.61TI0.39)O3/LANIO3/LAALO3ALL-PEROVSKITE

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GROWTH AND ELECTRICAL PROPERTIES OF LANIO3/PB(ZR0.61TI0.39)O...