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Effects of heat treatment on the properties of powder injection molded AlN ceramics

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Rare Metals 2008年第1期27卷 70-73页

作者： DU Xueli QIN Mingli Akhtar Farid FENG Peizhong QU Xuanhui Institute of Powder Metallurgy University of Science and Technology Beijing Beijing 100083 China School of Materials Science andEngineering Tianjin University of Technology Tianjin 300191 China

The effects of two different heat-treatment atmospheres,nitrogen atmosphere and reducing nitrogen atmosphere with carbon,on the properties of Y2O3-doped aluminum nitride（AlN） ceramics were *** AlN powder as a raw material was synthesized by self-propagating high-temperature synthesis（SHS） and compacts were fabricated by employing powder injection molding *** polymer-wax binder consisted of 60 wt.% paraffin wax（PW）,35 wt.% polypropylene（PP）,and 5 wt.% stearic acid（SA）.After the removal of binder,specimens were sintered at 1850°С in nitrogen atmosphere under atmospheric *** improve the thermal conductivity,sintered samples were *** result reveals that the heat-treatment atmosphere has significant effect on the properties and secondary phase of AlN *** thermal conductivity and density of AlN ceramics reheated in nitrogen gas are 180 W·m^-1·K^-1 and 3.28 g·cm^-3 and the secondary phase is yttrium *** the sample reheated in reducing nitrogen atmosphere with carbon,the thermal conductivity and density are 173 W·m^-1·K^-1 and 3.23 g·cm^-3,respectively,and the secondary phase is YN.

关键词： powder injection molding AIN ceramics heat treatment thermal conductivity

DECOMPOSITION OF BV FUNCTIONS IN CARNOT-CARATHEODORY SPACES

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Acta Mathematica Scientia 2003年第4期23卷 433-439页

作者：宋迎清杨孝平刘振海 School of Science Nanjing University of Science and Technology Nanjing 210094 China Department of Mathematics Hunan University of City Yiyang 413000 China School of Science Nanjing University of Science and Technology Nanjing 210094 China Department of Mathematics Changsha University of Electrical Power Changsha 410077 China

The aim of this paper is to get the decomposition of distributional derivatives of functions with bounded variation in the framework of Carnot-Caratheodory spaces (C-C spaces in brievity) in which the vector fields are of Carnot type. For this purpose the approximate continuity of BV functions is discussed first, then approximate differentials of L1 functions are defined in the case that vector fields are of Carnot type and finally the decomposition Xu = (?)u ·Ln + X2 u is proved, where u ∈ BVx(?) and (Ω)u denotes the approximate differential of u.

关键词： BV function C-C space Radon measure vector field approximate differential

GRAIN REDUCTION AND GROWTH IN FAULTINGAND NEW CLASSIFICATION OF FAULTED ROCKS

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Journal of Central south university 1996年第1期8卷 46-48页

作者： Duan Jiarui Kong Hua(Department of Geology, Central south university of technology,Changsha 410083, china)

New classification scheme about faulted rocks is proposed, according to the extent of grain reduction and growth and their sequence, and faulted rocks are classified as follows: (1) faulted rocks formed by the reduction action mainly include breccia series, cataclasite series, tectonobutchite series, mylonite series; (2) faulted rocks formed by growth action is mainly tectonoschist (gneiss) series; (3) blastomylonite series formed by grain reduction first and then growth; (4) mylonitic schist (gneiss) series formed by crystal growth first and then grain reduction. All series can be further classified according to matrix contents.

关键词： reduction growth faulting classification〖J

Development and applications of solids-free oil-in-water drilling fluids

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Petroleum Science 2008年第2期5卷 153-158页

作者： Yue Qiansheng Ma Baoguo Key Laboratory of Silicate Materials Science and Engineering Wuhan University of Technology Wuhan Hubei 430070 China Yangtze university Jingzhou Hubei 434023 China

The increasing application of near balanced drilling technology to low-pressure and depleted fractured reservoirs requires the use of low-density drilling fluids to avoid formation damage. Solidsfree oil-in-water （O/W） emulsion drilling fluid is one type of low-density drilling fluid suitable for depleted fractured reservoirs. In this paper, the solids-free O/W drilling fluid was developed and has been successfully used in the Bozhong 28-1 oil and gas field, by which lost circulation, a severe problem occurred previously when drilling into fractured reservoir beds, was controlled, thereby minimizing formation damage. The O/W emulsion drilling fluid was prepared by adding 20% （by volume） No. 5 mineral oil （with high flash point, as dispersed phase） into seawater （as continuous phase）. Surfactant HTO-1 （as a primary emulsifier） and non-ionic surfactant HTO-2 （as a secondary emulsifier） were added into the drilling fluid system to stabilize the emulsion; and YJD polymer was also added to seawater to improve the viscosity of the continuous phase （seawater）. The drilling fluid was characterized by high flash point, good thermal stability and high stability to crude oil contamination.

关键词： Oil-in-water emulsion drilling fluids solids-free drilling fluids lost circulation depletedreservoir fractured reservoir

Fuzzy interface treatment in Eulerian method

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Science china(Technological Sciences) 2004年第5期47卷 550-568页

作者： NING Jianguo1 & CHEN Longwei1,2 1. National Key Laboratory of Protection and Control of Explosive Disaster, Beijing Institute of technology, Beijing 100081, china 2. The Faculty of Land Resource Engineering, Kunming university of Science and technology, Kunming 650093, china Correspondence should be addressed to Ning Jianguo 1. National Key Laboratory of Protection and Control of Explosive Disaster Beijing Institute of Technology 100081 Beijing China 2. The Faculty of Land Resource Engineering Kunming University of Science and Technology 650093 Kunming China

In this paper, we incorporate fuzzy mathematics approach into the Eulerian method to simulate three dimensional multi-material interfaces. In particular, we propose a fuzzy interface treatment for describing interfaces, designing transport plans, and computing transport quantities. Using a set of three-dimensional inviscid isothermal elastic-plastic hydrodynamic equations, we simulate shaped charge jet in different filled dynamite structures. Strain and stress have been under consideration in simulations. Numerical results demonstrate that the fuzzy interface treatment is correct and efficient for three-dimensional multi-material problems.

关键词： Eulerian method, multi-material, fuzzy interface, shaped charge jet, three-dimensional numerical simulation.

STATISTICAL EVALUATION OF CRITICAL INCLUSION FACTOR FOR SECONDARY RECRYSTALLIZATON IN 3%Si STEEL Lecturer,Department of Materials Engineering,southwestern Jiaotong university,Chengdu 610031,china

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Acta Metallurgica Sinica(English Letters) 1990年第5期3卷 327-331页

作者： LI Shuchen southwestern Jiaotong university,Chengdu,chinaCHEN Mengzhe KE Jun university of Science and technology Beijing,Beijing,china

On the basis of statistical data of MnS in the conventional 3% Si steel sheeets after various annealing processes,the critical inclusion factor has been evaluated to be 20 mm^(-1).The inhi- bition of MnS to grain grow... 详细信息

关键词： 3%Si steel secondary recrystallization inclusion factor

Mechanical behaviors of alumina ceramics doped with rare-earth oxides

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Rare Metals 2010年第5期29卷 456-459页

作者： YAO Yijun LI Chuncheng WANG Ling JIANG Xiaolong QIU Tai School of Mathematics and Physics Nanjing University of Information Science & Technology Nanjing 210044 China College of Materials Science and Engineering Nanjing University of Technology Nanjing 210009 China

The effects of three types of additives Y2O3, La2O3, and Sm2O3 on the sintering and mechanical behaviors of alumina ceramics were investigated. The bending strengths of alumina ceramics with Sm2O3 and Y2O3 additions were 455 and 439 MPa, respectively, higher than that with La2O3 addition. The fi＇acture toughness of the ceramics with Sm2O3 and Y2O3 were also higher than that with La2O3 addition. The fracture mode of rare earth oxides doped alumina ceramics exhibited obvious transgranular fractures as well as intergranular fracture. The results of research show that the improvement of bending strength and fracture toughness of alumina ceramics with rare earth oxides was achieved by refining the grain size and strengthening the grain boundary.

关键词： rare earths alumina doping mechanical properties microstructure

Copper Adsorption on Olivine

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 237-241页

作者： Lei Shao, Rolf A. Kleiv, Kunt L. Sandvik, Cunyi Song, Shouci Lu ( Resources Engineering School, university of Science and technology Beijing, Beijing 100083, china Department of Geology and Mineral Resources Engineering, Norwegian university of Science a Resources Engineering School University of Science and Technology Beijing Beijing 100083 China Department of Geology and Mineral Resources Engineering Norwegian University of Science and Technology 7034 Trondheim Norway

Copper adsorption on olivine supplied by the A/S Olivine Production Plant at Aheim in western Norway was studied. The factors were evaluated which affect the uptake of copper. It is shown that the equilibrium pH of aqueous solution has the greatest influence on copper adsorption thanks to the competitive adsorption between proton and copper ions, and the adsorption of copper to olivine increases rapidly with pH increasing from 4 to 6. Moreover, initial copper concentration and olivine dose possess significant effect on copper adsorption, for the adsorption rate of copper increases with olivine dose increasing or initial copper concentration decreasing at the same pH. In addition, the ionic strength effect on the adsorption was also investigated, but it owns little effect on the adsorption process of copper due to the formation of inner sphere adsorption of copper on olivine. The experimental data show that olivine has a high acid buffer capacity and is an effective adsorbent for copper.

关键词： copper adsorption olivine, ionic strength acid mine drainage

Crystallization behavior of Zr_(52) Cu_(18) Ni_(15) Al_(10) Ti_5 bulk glass with quenched-in crystals

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中国有色金属学会会刊：英文版 2000年第3期10卷 345-348页

作者： BIAN Zhan(边赞), HE Guo(何国), CHEN Guo liang(陈国良) State Key Laboratory of Advanced Metals and Materials, university of Science and technology Beijing, Beijing 100083, P.R.china Univ Sci & Technol Beijing State Key Lab Adv Met & Mat Beijing 100083 Peoples R China

Zr 52 Cu 18 Ni 15 Al 10 Ti 5 bulk glass samples with a diameter of 8 mm prepared by copper mold with water cooling have a mixing structure of amorphous phase and quenched in crystals. By isothermal annealing at different temperatures, the crystallization process of the glass alloy is shown to be a multi staged crystallization reaction as follows: Am+quenched in crystals→Am′+cellular phase+(Zr, Ti) Al→Am′+cellular phase+(Zr, Ti) Al+(Zr, Ti) 2(Cu, Ni). Morphology of the quenched in crystals changes from dot or dendritic phase in the as cast bulk glass to cellular phase at different annealing states. The residual region surrounded by the cellular phase has a mixing structure of nano scale phase and amorphous phase.

关键词： bulk glass quenched in crystals crystallization nano scale phases