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Diffusion Kinetics of Carbonate Hydroxyapatite (CHAP) for Adsorbing F^- Dissolved in Water

Acta Geologica Sinica(English Edition) 2006年第2期80卷 243-248页

作者： HUANG Zhiliang ZHANG Lianmeng LIU Yu WANG Qilin HE Qianjun CHEN Wei State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan Hubei 430070 Research Institute of Mineral Material Wuhan Institute of Technology Wuhan Hubei 430073

A systematic research was performed about diffusion kinetics of adsorbing F^- dissolved in water for carbonate hydroxyapatite （CHAP） from the natural hydroxyapatite which was modified by adulterating with CO3^2-. The result shows that the speed of F^- adsorption is controlled by membrane diffusion when F^- concentration is relatively low, which is expressed by the kinetic equation of diffusion Q=0.0005（Ci-C）（t-ti）＋0.3967, or by vacancy diffusion when F^- concentration is relatively high, which is expressed by the kinetic equation of diffusion In[C（o, t）]=8.4718-0.5048Int. Based on the feature of CHAP for adsorbing F^- dissolved in water and its special channel of the structure of CO3^3- modified hydroxyapatite, models of vacancy diffusion and membrane diffusion were established.

关键词： carbonate hydroxyapatite （CHAP） F^- ion diffusion kinetics

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Study on the isothermal oxidation behavior in air of Ti_(3)AlC_(2) sintered by hot pressing

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Science China(Technological Sciences) 2006年第5期49卷 513-520页

作者： XU Xuewen1, 2, LI Yangxian1, MEI Bingchu2, ZHU Jiaoqun2, LIU Heyan1 & QU Jingping1 1. School of material Science and Engineering, Hebei University of technology, Tianjin 300130, China 2. state key laboratory of advanced technology for materials synthesis and processing, Wuhan Univer- sity of technology, Wuhan 430070, China 1. School of Material Science and Engineering Hebei University of Technology Tianjin 300130 China 2. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

The isothermal oxidation behavior at 900–1300°C for 20 h in air of bulk Ti3AlC2 with 2.8 wt% TiC sintered by means of hot pressing was investigated in the work. The isothermal oxidation behavior generally followed a parabolic rate law. The parabolic rate constants increased from 1.39×10[10] kg[2]·m[4]·s[1] at 900°C to 5.56×10[9] kg[2]·m[4]·s[1] at 1300°C. The calculated activation energy was 136.45 kJ/mol. It was demonstrated that Ti3AlC2 had excellent oxidation resistance due to the continuous, dense; adhesive protect scales consisted of a mass of α-Al2O3; a little of TiO2;/or Al2TiO5. In principle, the oxide scale was grown by the inward diffusion of O[2]; the outward diffusion of Ti[4+]; Al[3+]. The rapid outward diffusion of cations usually resulted in the formation of cracks, gaps,; holes.

关键词： Ti3AlC2, oxidation behavior, kinetics.

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synthesis and photoluminescence of Eu(DBM)_3phen/APTES-SBA-15 with morphology of pearl-like chains

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中国有色金属学会会刊：英文版 2006年第B01期16卷 356-360页

作者：赵春霞刘琦陈文田高徐玲芳 Institute of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan 430070China

Novel ordered mesoporous Eu(DBM)3phen/APTES-SBA-15 (EAS) composites with reasonable photoluminescence property and interesting morphology of bundles of pearl-like chains were synthesized. The characteristics of the mesostructure and the optical properties of the prepared samples were investigated by means of XRD, FTIR, SEM, TEM, N2 adsorption–desorption and PL spectroscopy. The results indicate that the as-made EAS composites have long-distance ordered mesoporous structure. Compared with the Eu(DBM)3phen complex, it is found that the EAS composites perform a considerable photoluminescence with good color purity. It is proposed that the anchored amine from the APTES and quantum size effect of the Eu(DBM)3phen complex have great effect on the photoluminescence of the EAS composites.

关键词： Eu(DBM)3phen/APTES-SBA-15 铕配合物合成光致发光珍珠链状结构形态学

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Research on shaping technology of nanocomposite WC-6Co powder and properties of sintered compacts

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International Journal of Nanoscience 2006年第2-3期5卷 233-238页

作者： Shi, Xiaoliang Shao, Gangqin Duan, Xinglong Yuan, Runzhang State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology 122 Luoshi Road Wuhan 430070 China

The influences of powder extrusfen molding (PEM), die pressing and cold isostatic pressing (CIP) on the green compacts and the sintered compacts of nanocrystalline WC-6Co composite powder produced by spray pyrogenation- continuous reduction and carburization technology were researched. The results showed that the pore volume distribution, density and scanning electron microscopy (SEM) morphologies of fractured surface of powder extrusion molding or die pressing followed by the cold isostatic pressing consolidation green compacts were better than that of powder extrusion molding or die pressing. The green compacts were sintered by using vacuum sintering plus hot isostatic pressing (HIP), the sintered specimens were characterized by testing density, Rockwell A hardness, saturated magnetization, coercivity force, transverse rupture strength (TRS) and atomic force microscope (AFM) images, the results showed that sintered specimen of the green body that prepared by powder extrusion molding or die pressing followed by cold isostatic pressing had excellent properties of high strength and high hardness, transverse rupture strength of sintered specimen was more than 3100 MPa, Rockwell A hardness of sintered body was more than 93. Ultrafine WC-6Co cemented carbide rods with excellent mechanical properties and fine microstructure were obtained. © World Scientific Publishing Company.

关键词： Nanotechnology

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Fabrication and properties of Ni-YSZ and Ni-Co-YSZ cermets

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International Journal of Nanoscience 2006年第2-3期5卷 225-231页

作者： Shao, Gang-Qin Li, Yong Duan, Xing-Long Cai, Hu Li, Jia Shi, Xiao-Liang Guo, Jing-Kun State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology 122 Luoshi Road Wuhan 430070 China

Ni-YSZ and Ni-Co-YSZ cermets were fabricated by hot-press-sintering from nanocomposite powders. The structure, morphology, relative density, hardness, specific heat capacity and thermal conductivity were measured. Results show that the crystalline grains are much homogeneous. Their size distribution is quite narrow and between 0.2-0.4 μm (200-400 nm). The Ni-Co-YSZ cermet reaches a maximum relative density (96.2%) at 1350°C and a maximum Rockwell hardness (70.5) at 1400°C. The specific heat capacity of Ni-YSZ cermet is larger than that of Ni-Co-YSZ cermet. The thermal conductivity of Ni-YSZ cermet is smaller than that of Ni-Co-YSZ cermet. © World Scientific Publishing Company.

关键词： Cermets

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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

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Characterization and properties of new dielectric ceramics Ba_5LnZnNb_9O_(30)(Ln=La, Nd and Sm)

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中国有色金属学会会刊：英文版 2006年第B02期16卷 534-537页

作者：朱文凤胡长征吴伯麟方亮 Key Laboratory of Nonferrous Materials and New Processing TechnologyMinistry of Education Guilin University of TechnologyGuilin 541004China Key Laboratory of Nonferrous Materials and New Processing TechnologyMinistry of Education Guilin University of Technology Guilin 541004China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

Three novel dielectric ceramics Ba5LnZnNb9O30 (Ln= La, Nd and Sm) were synthesized and characterized in the BaO-Ln2O3-ZnO-Nb2O5 quaternary system, which formed the filled tungsten-bronze structures. The present ceramics exhibit high dielectric constant (εr) up to 310, low dielectric loss in the level of 10 3 at 1 MHz. Meanwhile, the temperature coefficients of the dielectric constant (τε) of Ba5LnZnNb9O3o varies from -1 390×10-6 to -1 220×10-6/℃as the radius of Ln3+ increases. The present ceramics are promising candidates for high dielectric constant and low loss dielectric ceramics.

关键词：介电陶瓷 Ba5LnZnNb9O30 Ba5NdZnNb9O30 Ba5SmZnNb9O30 合成介电性质表征

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Fabrication of monolithic bulk Ti_3AlC_2 and impurity measurement by K-value method

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中国有色金属学会会刊：英文版 2006年第B02期16卷 490-493页

作者：徐学文富成科李养贤朱教群梅炳初 School of Materials Science and Engineering Hebei University of Technology Tianjin 300130 China Hebei Communications Vocational & Technical CollegeShijiazhuang 050091 China School of Materials Science and Engineering Hebei University of Technology Tianjin 300130China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

Polycrystalline bulk Ti3AlC2 material with high purity and density was fabricated by hot pressing from the powder mixture with the starting stoichiometric mole ratios of 2.0TiC/ 1.0Ti/ 1.1A1/ 0.1Si at 1 300-1 500℃. X-ray diffraction patterns and scanning electron microscopy photographs of the fully dense samples indicate that the proper addition of silicon is favorable to the formation of Ti3AlC2, consequently results in high purity of the prepared samples. The Ti3AlC2 hot pressed at 1 300℃and 1 400℃is in plane-shape with sizes of 6-8μm and 15-20μm in the elongated dimension, respectively. The purities of samples are measured by the K-value method, and the contents of TiC are given by a linear equation.

关键词：多晶单片Ti3AlC2陶瓷制造杂质纯度测量 Κ值法

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synthesis and X-ray Powder Diffraction Characterization of A New Niobate Crystal NaBa_2Li_(0.6)Nb_(4.8)Zn_(0.2)O_(15)

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Journal of Wuhan University of technology(materials Science) 2006年第1期21卷 1-3页

作者：欧阳世翕 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070ChinaChina Building Materials Academy Beijing 100024China

A new niobate compound was synthesized for the first time in Na2 O-BaO-Li2 O-ZnO-Nb2 O5 system by solid state reaction. The acw compound was studied by X-ray diffraction, electron probe, X-ray microanalysis, chemical analysis and SEM. The result of X-ray powder diffraction shows that NaBa2 Li0.6 Nb4.8 Zn0.2 O15 belongs to orthorhombic tungsten bronze structure, with space group Pba2（ 32 ） and lattice parameters a = 12.6115（2）A, b = 12.4981（2）A, C = 3.9479（3）A. The X-ray powder diffraction lines of the compoutid were well indexed.

关键词： nlobate ziac niobate structure XRD

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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

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