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A New Clustering Algorithm for Categorical Attributes

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International Journal of Minerals,Metallurgy and materials 2000年第4期14卷 318-322页

作者： Songfeng Lu, Zhengding Lu (college of Computer science and {2., Huazhong university of science and {2., Wuhan 430074, china) college of Computer science and {2. Huazhong University of Science and Technology Wuhan 430074 China

In traditional data clustering, similarity of a cluster of objects is measured by distance between objects. Such measures are not appropriate for categorical data. A new clustering criterion to determine the similarity between points with categorical attributes is pre- sented. Furthermore, a new clustering algorithm for categorical attributes is addressed. A single scan of the dataset yields a good clus- tering, and more additional passes can be used to improve the quality further.

关键词： data mining clustering similarity Information

Hot Corrosion of Iron in the Presence of Salt Mixture Deposit Containing NaCl and V_2._5 at 600℃

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Journal of materials science & {2. 1996年第6期12卷 445-451页

作者： Lingchuan LI (Dept. of materials science and {2., Tsinghua university Beijing 100084, china)Rizhang ZHU (Dept. of Surface science and Corrosion {2., university of science and technology Beijing, Beijing 100083, china)(To whom correspondenc Dept. of materials science and {2. Tsinghua University Beijing 100084 China Dept. of Surface science and Corrosion engineering University of Science and Technology Beijing Beijing 100083 China Instiuto di Chimica Facolta di Ingegneria Università di Genova Fiera del Mare Pad.D 16129 Genova Italy

Iron suffered low temperature hot corrosion (LTHC) in the presence of salt deposits of Na2.O4,Na2.O4 mixed with NaCl and Na2.O4 mixed with V2.5 in a combustion gas at 600℃. The additions of NaCl to Na2.O4 and of V2.5 to Na2.O4 changed the corrosion kinetics significantly and modified the scale structure markedly It is proposed that trivalent iron ions were more favored than divalent ions in the eutectic responsible for the occurrence of LTHC when NaCl was present, while the reaction between Na2.O4 mixed with V2.5 and the gas formed (Na2.)xV2.4(V2.5)6-x providing directly the liquid required by LTHC. The suphide formation in the inner FeO larer was related to the sites of the reduction step wher SO2.was released.

关键词： SO NaCl

Fabrication of Porous Bulk Metallic Glass

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Journal of materials science & {2. 2005年第6期21卷 788-790页

作者： Keqiang QIU+ and Yinglei REN School of materials science and {2., Shenyang university of technology, Shenyang 11002., china School of materials science and {2. Shenyang University of Technology Shenyang 110023 China

An open-cell porous bulk metallic glass （BMG） with a diameter of at least 6 mm was fabricated by using an U-turn quartz tube and infiltration casting around soluble NaCI placeholders. The pore formation and glassy structure were examined by optical microscopy （OM）, scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results show that the pores or cells are connected to each other and the specimen is composed of a mostly glassy phase. This paper provides a suitable method for fabrication of porous BMG and BMG with larger size in diameter.

关键词： Porous bulk metallic glass U-turn quartz tube Infiltration casting

Refinement of packet size in low carbon bainitic steel by special thermo-mechanical control process

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Journal of university of science and {2. Beijing 2004年第3期11卷 221-224页

作者： Chengjia Shang Xuemin Wang Shanwu Yang Xinlai He materials science and {2. School, university of science and technology Beijing, Beijing 100083, china Mat. Sci. and Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The packet size of bainitic steel can be refined by a specialrelaxation-precipitation-control phase transformation (RFC) technology. When processed by RPCprocess, the low carbon bainitic steel composes of two kinds of main intermediate transformationphases. One is ultra-fine lath-like bainitic ferrite and the lath is less than 1μm in width andabout 6 μm in length; the alignment of laths forms a refined packet, and the size of packets isabout 5-7 μm in length and about 3-4μm in width. The other is acicular structure. The morphologyand distribution of these acicular structures are influenced by relaxation process, the thin andshort acicular structures cut the prior austenite grain and refine the bainitic packet size. For theoptimum relaxation time, the packet size can be refined to the finest. The mechanical propertiesare influenced by relaxation time and the 800 MPa grade low carbon bainitic steel with excellenttoughness can be obtained by RPC process.

关键词： packet size refinement bainitic steel RPC process

The Effects of Aging Precipitation on the Recrystallization of CuNiSiCr Alloy

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Journal of Wuhan university of technology({2. science) 2005年第1期20卷 21-24页

作者：雷静果刘萍 college of Material Xi' an University of Technology Xi' an 710048 China School of Materials Science and Engineering Henan University of Scienc e & Technology Luoyang 471003 China

The interaction between precipitation and recrystallization and its effect on t he properties of the Cu-Ni-Si-Cr alloy during aging were *** result s show that the deformation results in much more dispersed precipitation of the phases. The precipitations have accelerating or retarding effects on the recryst allization. On the formation and growth of recrystallization, the precipitated p hases are coarsed or dissolved in front of grain boundaries following a re-prec ipitation in the recrystallization area.

关键词： CuNiSiCr alloy aging precipitation recrystallization

Comparative Analysis on Microstructure and Mechanical Properties between EBW and TANDEM Welding of 7A52.Aluminum Alloy Joint

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稀有金属材料与工程 2011年第S4期40卷 68-73页

作者： Zhai Xiwei1,2.Chen Furong1,2.Bi Liangyan1,2.Zhang Chuanchen3 1college of materials {2. and engineering,Inner Mongolia university of technology,Hohhot 010051,china2.ey Laboratory of materials Processing & Control engineering of Inner Mongolia Autonomous Region,Hohhot 010051,china3School of materials {2. and engineering,university of {2. and technology Beijing,Beijing 100083,china Inner Mongolia Univ Technol Coll Mat Sci & Engn Hohhot 010051 Peoples R China Key Lab Mat Proc & Control Engn Inner Mongolia Au Hohhot 010051 Peoples R China Univ Sci & Technol Beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China

The plates with 2.mm thickness of 7A52.aluminum alloy were welded by electron beam welding and TANDEM welding with ER5356 filler,*** microstructure and mechanical properties of the joints were *** results showed that the microstructure of EBW metal was finer and tighter than TANDEM *** heat-affected zone of the EBW joint was narrower,its hardness was higher and the tensile strength improved obviously compared to TANDEM *** quality control of the EBW joint was made without abnormal porosity,inclusions and ***,the EBW joint of 7A52.aluminum alloy showed excellent performance.

关键词： 7A52 aluminum alloy electron beam welding TANDEM welding microstructure mechanical properties

Electrochemical Study of Hypophosphite

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International Journal of Minerals,Metallurgy and materials 1998年第1期12卷 23-25页

作者： Yuguo Yang Dongbai Sun Dongbai Sun Dejun Yang (materials science and {2. School, university of science and technology Beijing, Beijing 100083, china) materials science and {2. School University of Science and Technology Beijing Beijing 100083 China

Electrochemical behavior of hypophosphite was studied with cyclic voltammogram in acidic solution(pH = 4.6) at 80℃. Two anodic peaks were observed on gold electrode at - 0.44V and - 0.59 V (SCE),respectively, and no corresponding cathodic peaks were obtained. The one at - 0.44 V wits ascribed to the oxidation oftautomeric form of hypophosphite, the other at - 0.59 V was due to the oxidation of absorbed form of hypophosphite. The two oxidation reactions were believed to be the electron source of nickel ion reduction in electrolessnickel processes.

关键词： cyclic voltammogram electroless nickel plating gold electrode hypophosphite

Magnetic properties and structure of very thin permalloy films

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Journal of university of science and {2. Beijing 2004年第3期11卷 225-229页

作者： Guanghua Yu Haifeng Li Tao Yang Fengwu Zhu materials science and {2. School, university of science and technology Beijing, Beijing 100083, china Mat. Sci. and Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

In order to study the magnetic properties and structure of very thinpermalloy films, Ni_(81)Fe_(19) films of 12.nm in thickness were prepared by different instrumentsat an ultrahigh base vacuum and a lower base vacuum. The anisotropic magnetoresistance coefficients(ΔR/R) of Ni_(81)Fe_(19) (12.nm) films reached 1.6 % and 0.6 %, and the coercivities were 12. and334 A/m, respectively. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were usedto study the structure and surface chemical state. The experimental results show that the filmsprepared at the ultrahigh base vacuum have a smoother surface, a bigger grain size and a denserstructure with fewer defects than those prepared at the lower base vacuum.

关键词： NiFe film anisotropic magnetoresistance (AMR) coercivity structure

Study on Modification Mechanism of Rare Earth in ZA2. Cast Alloy with Electronic Theory and Molecular Dynamics Method

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Journal of materials science & {2. 2004年第5期20卷 586-588页

作者： Guili LIU, Rongde LI and Zhenping ZHOUSchool of materials science and {2., Shenyang university of technology, Shenyang 11002., china Sch. of Mat. Sci. and Eng. Shenyang Univ. of Technol. Shenyang 110023 China

A model of liquid ZA2. cast alloy is established according to molecular dynamics theory and an atomic structural model of co-existent a phase and liquid is also presented by means of computer programming. Recursion method is adopted to calculate the electronic structure of RE (rare earth) in grains and around phase boundaries respectively. The calculation shows that RE is more stable around phase boundaries than in grains, which explains the fact that the solution of RE in a phase is less, and RE mainly aggregates in front of phase boundary. The calculations of bonding order integrals also show that RE in front of phases hardly solidify onto the grain surfaces as active element so as to prevent grains growth and refine the grains. As a result, the modification mechanism of RE may be explained from the view of electronic structure.

关键词： Atomic structural model Recursion method Electronic structure Modification mechanism Rare easth