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Manufacture of the Ultrafine Grain WC/Co Cemented Carbides by Combined Sintering Processing

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International Journal of Minerals,Metallurgy and materials 1999年第3期13卷 208-213页

作者： Binghai Liu Yue Zhang Shixi Ouyang Qikai Li(Institute of Technical Physics and Chemistry, East china university of science and Technology , Shanghai 20023., china)(material science and engineering school. university of science and Technology beijing, beijing 100083, china)(State Key Laboratory for Synthesis and Processing of Advanced materials. Wuhan university of science and Technology, Wuhan 43.070, china,) E china Univ Sci & Technol Inst Tech Phys & Chem Shanghai 200237 Peoples R China Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China Wuhan Univ Sci & Technol State Key Lab Synth & Proc Adv Mat Wuhan 430070 Peoples R China

A new kind of sintering process, combined sintering process. i.e. vacuum sintering plus hot isolate pressure sintering (HIP), was introduced for producing ultrafine WC-10% Co (mass fraction. so as the follows) cemented carbides. The effects of some processing parameters on the microstructure and mechanical properties of the obtained cemented carbides were studied. The results show that the rapid shrinkage and the pronounced densification of tile cemented carbides took place during the vacuum sintering stage, which is intinaately correlated with the local liquid sintering occurred during this earl} sintering stage for the high surface activity of ultrafine WC-Co powder. The way of high pressure imposing. isothermal treatment cycle during *** sintering and HIP sintering stage directly influence the densitication of compacts and the mechanical properties of the produced WC-10%Co cemented carbides.

关键词： ultrafine WC-Co cemented carbides vacuum sintering HIP sintering

Rapid Sintering of Alumina in Low Pressure RF Plasma

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International Journal of Minerals,Metallurgy and materials 1999年第2期13卷 133-135页

作者： Wenxia Pan Fanxiu Lu Toyonobu Yoshida (InstitUte of Mechanics, Chinese Academy of sciences, beijing 100080, china) ({3. science and engineering school, university of science and Technology Beliing, Beliing 100083, china) (Department of Metallurgy, Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China material science and engineering {3. University of Science and Technology Beijing Beijing 100083 China Department of Metallurgy University of Tokyo Tokyo 113 Japan

Three kinds of high-purity A12O3.powders, whose average paticle size is 0. l, 0.3.and 3.0 mp respectively, were used as thestarting power, and their compacts were fired in the radio-frequency plasma generated at a pressure of 80 Pa using N, as the working *** results show that the 0. 1 and 0.3.mp powder compacts can be sintered to nearly the theoretical density within 60 s and thissintering is almost finished in the heating period. It is concluded that the mechanism of liquid sintering, the electric charge effect of Al2O3.owder, and the effect of tempetrature gradient in the compacts can affect simultaneously on the rapid densification of the compacts inthe plasma sintering.

关键词： plasma sintering alumina rapid heating

Shape Character of Fusion-solidification Zone of EBW Joints for Titanium Alloy

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稀有金属材料与工程 2011年第S4期40卷 74-78页

作者： Fu Pengfei1,2,Mao Zhiyong2,Wang Yajun3.Gong Shuili2,Liu Xin2 1school of materials science and {3.,Huazhong university of science and Technology,Wuhan 43.074,china 2science and Technology on Power Beam Processes Laboratory,beijing Aeronautical Manufacturing Technology Research Institute,beijing 100024,china3.0} of Mechanical {3. and Automation,beijing university of aeronautics and astronautics,beijing 100191,china beijing Aeronaut Mfg Technol Res Inst Sci & Technol Power Beam Proc Lab Beijing 100024 Peoples R China Huazhong Univ Sci & Technol Sch Mat Sci & Engn Wuhan 430074 Peoples R China beijing Univ Aeronaut & Astronaut Sch Mech Engn & Automat Beijing 100191 Peoples R China

Shape character of fusion-solidification zone of electron beam welding (EBW) joints was studied for TC4 *** typical shapes of the fusion-solidification zone were gained by appropriate welding *** shapes and dimensions of the fusion-solidification zone of TC4 titanium joints were apparently influenced by processing parameters,focusing state and power density *** on the analyses of processing parameters,focusing state and power density distribution,the integrated parameters of n1 and n2 were put forward,which represented the distribution and intensity of electron beam *** a series of the formulations are developed to predict the shape of fusion-solidification zone by the processing parameters.

关键词： electron beam welding (EBW) titanium alloy fusion-solidification zone mathematical model

ROBUST NONPARAMETRIC REGRESSION BASED ON L_1-NORM AND B-SPLINES

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Systems science and Mathematical sciences 1995年第2期8卷 187-192页

作者： SHI Peide(Department of Probability and Statistics, Peking university, beijing 100871,china)ZHANG Zhengjun({3. Of Management,beijing university of aeronautics and astronautics,beijing 100083, china) 北京大学概率统计系北京北京航空航天大学管理学院北京

ＲＯＢＵＳＴＮＯＮＰＡＲＡＭＥＴＲＩＣＲＥＧＲＥＳＳＩＯＮＢＡＳＥＤＯＮＬ＿１－ＮＯＲＭＡＮＤＢ－ＳＰＬＩＮＥＳＳＨＩＰｅｉｄｅ（ＤｅｐａｒｔｍｅｎｔｏｆＰｒｏｂａｂｉｌｉｔｙａｎｄＳｔａｔｉｓｔｉｃｓ，Ｐｅｋｉｎｇ... 详细信息

ＲＯＢＵＳＴＮＯＮＰＡＲＡＭＥＴＲＩＣＲＥＧＲＥＳＳＩＯＮＢＡＳＥＤＯＮＬ＿１－ＮＯＲＭＡＮＤＢ－ＳＰＬＩＮＥＳＳＨＩＰｅｉｄｅ（ＤｅｐａｒｔｍｅｎｔｏｆＰｒｏｂａｂｉｌｉｔｙａｎｄＳｔａｔｉｓｔｉｃｓ，ＰｅｋｉｎｇＵｎｉｖｅｒｓｉｔｙ，Ｂｅｉｊｉｎ...

关键词： B-spline function L1-norm estimator TURBO nonparametric regression

Corrosion Behavior of Mg_(65)Cu_(25-x) Zn_xGd_(10)(x=0, 5) Metallic Glass

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Journal of Wuhan university of Technology(materials science) 2008年第5期23卷 678-682页

作者：李国强 school of materials science and {3. Beijing University of Aeronautics & Astronautics

The effect of substitutional element Zn on corrosion behavior of Mg65Cu25Gd10 glass was investigated. The amorphous structure of Mg65Cu25-xZnxGd10 （x=0,5） alloys were examined by X-ray diffractometry and differential scanning calorimetry （DSC）. The dissolution rates of Mg65Cu25-xZnxGd10 （x=0, 5） metallic glasses in a 5 wt% NaCl solution with pH value of 7 were determined by a hydrogen evolution testing method. The corrosion behavior of these alloys was characterized using dipping tests with 5 wt% NaCl, in combination with electrochemical measurements and scanning electron microscopy （SEM）. Results show that the anti-corrosion ability of Mg65Cu25Gd10 alloy is significantly improved due to the addition of Zn. Possible mechanism responsible for the improvement is discussed.

关键词： Mg-based metallic glass corrosion behavior corrosion resistance dissolution rate

Optical and acoustic phonon modes confined in gallium phosphide nanoparticles

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Rare Metals 2010年第6期29卷 561-566页

作者： ZHANG Zhaochun and ZHANG Neng school of material science and {3.,Shanghai university,Shanghai 200072,china school of material science and {3. Shanghai University Shanghai China

The main aim of this paper is to discuss the confinement effects on the optical and acoustic phonon vibrational modes in gallium phosphide（GaP） nanoparticles（cylindric grain）.The Raman scattering from the GaP nanoparticles was *** was found that the red-shifts of the longitudinal optical（LO） mode and transverse optical（TO） mode were 15 cm？1 and 13.8 cm？1,*** is generally accepted that the red-shifts of the optical phonon modes are due to the presence of smaller nanosized particles（～1.2 nm） acting as the nanoclustered building blocks of the GaP *** the low frequency Raman spectrum,a set of Stokes lines with almost the same spacing was clearly *** scattering feature originates from the discrete phonon density of states of the nanoclustered building *** to Lamb＇s vibrational theory,the Raman shift wavenumbers of the spheroidal mode and torsional mode of the lowest energy surface modes for the nanoclustered building blocks were *** agreement can be achieved between the calculated results and the observed scattering *** results indicate that the corresponding Raman peaks are due to scattering from the localized acoustic phonons in the nanoclustered building blocks in the GaP nanoparticles.

关键词： spectroscopy phonon mode Raman scattering gallium phosphide nanoparticles confinement effects

A construction of hyperbent functions with polynomial trace form

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science china Mathematics 2011年第10期54卷 2229-2234页

作者： CAO XiWang1,2,3.& HU Lei3.1Department of Mathematics,Nanjing university of aeronautics and astronautics,Nanjing 210016,{3. 2LMIB of Ministry of Education,beijing university of aeronautics and astronautics,beijing 100191,{3. 3.tate Key Laboratory of Information Security,Graduate school of Chinese Academy of sciences,beijing 100049,{3. 1. Department of Mathematics Nanjing University of Aeronautics and Astronautics Nanjing 210016 China2. LMIB of Ministry of Education Beijing University of Aeronautics and Astronautics Beijing 100191 China3. State Key Laboratory of Information Security Graduate School of Chinese Academy of Sciences Beijing 100049 China

This paper presents a construction of infinite classes of binary and p-ary hyperbent functions of polynomial trace form,based on finding a zero of a Kloosterman sum.

关键词： bent function hyperbent function Kloosterman sums

The Utility Additive Method and Its Usage for Studying Consumer Behavior

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Systems science and Systems engineering 2002年第2期11卷 150-157页

作者： SONG Jun, XU Zheschool of Economics and Management beijing university of {3. and astronautics beijing 100083 china school of Economics and Management beijing 100083 China beijing university of aeronautics and {3. beijing 100083 China

Multiattribute utility theory is a powerful theory tool to reveal the preferences of the consumers according to multiple attribute points of view. Utility additive (UTA) method based on Multiattribute utility theory is an ordinal regression method using linear programming. The purpose of the UTA method presented in this paper is to assess additive utility functions that aggregate multiple attributes in a composite attribute. The results of it are important for the study of consumer behavior. Finally, a simple illustrative example is presented and some extensions of the method are proposed.

关键词： multiattribute utility theory linear programming consumer behavior

Performance comparison and parametric study on spiral groove gas film face seals

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science china(Physics,Mechanics & Astronomy) 2004年第z1期47卷 29-36页

作者： LIU Yuchuan, SHEN Xinmin, XU Wanfu & WANG ZhiliState Key Laboratory of Tribology, Tsinghua university, beijing 100084, china {3. of Mechanical engineering and Automation, beijing university of aeronautics and astronautics, beijing 100083, china Lubrication Technology Research Center, Shenyang Institute of Technology, Shenyang 110015, china Tsing Hua Univ State Key Lab Tribol Beijing 100084 Peoples R China beijing Univ Aeronaut & Astronaut Sch Mech Engn & Automat Beijing 100083 Peoples R China Shenyang Inst Technol Lubricat Technol Res Ctr Shenyang 110015 Peoples R China

Several spiral groove gas film face seals (SGFS) with different layouts are compared quantitatively to analyze their merits and faults and application behaviors. In addition, a parametric study on downstream mode SGFS is conducted to determine its optimal parameters under certain working conditions. In tne computation of gas film pressure on the face, finite element method (FEM) is applied to adapt to complicated geometrical boundary.

关键词： spiral groove, gas film face seals, parameter study, performance comparison, finite element method.