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LUBRICATING BEHAVIOR OF COPPER RHENATE AT ELEVATED TEMPERATURES

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中国有色金属学会会刊：英文版 1997年第4期7卷 44-47页

作者： Xiong Dangsheng National key laboratory for powder metallurgy, central south university of Technology, changsha 410083

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关键词： copper rhenate high temperature lubrication rubbing pairs

Biocompatibility evaluation in vitro. Part III: Cytotoxicity expression of human and animal osteoblasts on the biomaterials

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Journal of central south university 2001年第3期13卷 147-155页

作者： RUAN Jian-ming 1,M.H. Grant 2 (1. state key laboratory for powder metallurgy, central south university, Changs ha 410083, china 2. Bioengineering Unit, Strathclyde university, Glasgow, G4 0NW, UK) 1. state key laboratory for powder metallurgy Central South University 410083 Changsha China 2. Bioengineering Unit Strathclyde University G4 0NW Glasgow UK

Exclusion and inflammation in the clinic are observe d for various reas ons including material che- mical composition, physical properties as well a s macr o- and micro-structure of the implants, surface condition of the implants, and also patient dependent factors. Cytotoxicity expression of cells is a central issue i n current biocompatibility to screen the potential implant materials and drugs. This study was aimed at investigation reaction between the potential implant mat erials and surround tissue. Cytotoxicity of human and rat osteoblast in the mate rial extracts was determinated by testing standards such as GHS assay, MTT assay , alkaline phosphatase activity assay, LDH assay, and Lowry assay. Research resu lts demonstrated that compared with the control condition polystyrene culture pl a te both human and rat osteoblast cells have normal phenotypic expression in hydr oxyapatite extract, and this expression was statistically restricted in hydroxya patite-spinel extract. How- ever, this restrict, e.g. cytotoxicity could be partially eliminated by immersion treatment of the materials in culture medium.

关键词： biomaterial cytotoxicity biological molecular technique

Finite Element Analysis of Die Geometry and Process Conditions Effects on Equal Channel Angular Extrusion for β-Titanium Alloy

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Journal of Iron and Steel Research International 2012年第10期19卷 54-58页

作者： SI Jia-yong1,2, GAO Fan3, ZHANG Ji3 (1. state key laboratory of powder metallurgy, central south university, changsha 410083, Hunan, china 2. College of Mechanical and Electrical Engineering, central south university of Forestry and Technology, changsha 410004, Hunan, china 3. High Temperature Material Research Division, central Iron and Steel Research Institute, Beijing 100081, china) [a] state key laboratory of powder metallurgy Central South University Changsha 410083 Hunan China [b] College of Mechanical and Electrical Engineering Central South University of Forestry and Technology Changsha 410004 Hunan China [c] High Temperature Material Research Division Central Iron and Steel Research Institute Beijing 100081 China

The finite element analysis was applied to evaluate the respective influences of die geometry and process conditions on plastic strain distribution for β-titanium (Ti-13V11Cr3Al) alloy during the equal channel angular extrusion (ECAE). It was found that optimum equal channel angular extrusion die geometry is strongly material dependent. Optimal strain homogeneity in the Ti-13V11Cr3Al alloy may be achieved at r (inner radius)=5 mm, R (outer radius)=3 mm. The equivalent plastic strain increases with increasing friction coefficient. And the better homogeneity of the equivalent plastic strain distribution can be achieved when friction coefficient value is lower. The faster the ram speed is, the lower the homogeneity of the equivalent plastic strain distribution is and the influence is slight. The back-pressure does not help to improve the plastic strain homogeneity, and the increasing temperature has a slightly favourable effect on the plastic strain homogeneity between 400 and 600 ℃.

关键词： equal channel angular extrusion finite element analysis die geometry β-titanium

Facile synthesis of La_2Mo_2O_9 nanoparticles via an EDTA complexing approach

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Rare Metals 2008年第4期27卷 340-344页

作者： CHENG Hua WANG Hongen LI Liang LU Zhouguang QIAN Dong College of Chemistry and Chemical Engineering Central South University Changsha 410083 China state key laboratory of powder metallurgy Central South University Changsha 410083 China

A facile EDTA （ethylene diamine tetraacetic acid） complexing technique has been successfully employed to prepare La2Mo2O9 nanoparticles. The as-synthesized products are characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and Fourier transform infrared spectroscopy （FT-IR）. The results show that a homogeneous transparent gel can be obtained with EDTA as the organic complexing reagent under the pH value of 3.0. Further thermal decomposition of the as-synthesized transparent gel by increasing the temperature up to 600℃ for 3 h results in the formation of La2Mo2O9 nanoparticles with a crystal size of about 30 nm. Moreover, the nanoparticles tend to form micrometer-sized aggregates with a three-dimensional network structure, which shows promising applications in solid oxide fuel cells （SOFC）, catalysts and so on.

关键词： inorganic non-metal materials EDTA complexing sol-gel La2Mo2O9 nanoparticles porous structure

Microstructure Analysis of Microwave Sintered Ferrous PM Alloys

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Journal of Wuhan university of Technology(Materials Science) 2009年第2期24卷 214-217页

作者：彭远东易健宏 state key laboratory for powder metallurgy Central South University

The properties and microstructure of microwave and conventional sintered Fe-2Cu-0.6C powder metallurgy （PM） alloys were investigated. The experimental results show that microwave sintered alloy has the better properties （sintered density 7.20 g/cm3, Rockwell hardness 75 HRB, tensile strength 413.90 MPa and elongation 6.0%）, compared with the conventional sintered counterpart. Detailed analyses by using optical microscopy and scanning electron microscopy （SEM） reveal that microwave sintered sample has finer microstructure with small, rounded and uniformly distributed pores, and also demonstrate the presence of more flaky and granular pearlite in the mi- crowave sintered body, both of which account for the property improvement. SEM images on the fracture morphology indicate that a mixed mode containing ductile and brittle fracture is presented in microwave sintered alloy, in contrast with the brittle fracture in conventional sintered counterpart.

关键词： microwave sintering Fe-Cu-C PM alloys mechanical property microstructure

Heat transfer analysis for the roller shell under the condition of periodic thermal shock

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Journal of university of Science and Technology Beijing 2003年第6期10卷 44-47页

作者： Lihua Zhan and Xiaoqian LiCollege of Electro-mechanical Engineering, central south university, changsha 410083, china College of Electro-mechanical Engineering Central South University Changsha 410083 China

According to the actual working conditions of roller shell in the process ofcontinuous roll casting, the Fourier heat transfer law is used to conduct the simulating analysisfor the temperature distribution of the roller shell under the condition of periodic thermal *** temperature variation law inside the roller shell is studied during the process of continuousroll casting, and the steady temperature distributions of the roller shell at different castingvelocities have been obtained when the thermal contact conductance between the roller shell and thecasting strip is considered.

关键词： roller shell thermal contact conductance (TCC) periodic thermal shock

Modeling Study on Stress Distribution as Effects of Temperature and TGO Thickness in ScYSZ/NiCrAlY TBCs System

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稀有金属材料与工程 2011年第S4期40卷 164-168页

作者： Liu Huaifei1,2,Li Qilian2,Li Songlin1,Li Yongming1 1state key laboratory of powder metallurgy,central south university,changsha 410083,china 2National key laboratory of Science and Technology on Power Beam Process,Beijing Aeronautical Manufacturing Technology Research Institute,Beijing 100024,china Cent S Univ State Key Lab Powder Met Changsha 410083 Peoples R China Beijing Aeronaut Mfg Technol Res Inst Natl Key Lab Sci & Technol Power Beam Proc Beijing 100024 Peoples R China

The effects of oxidation temperature and thickness of thermally grown oxide (TGO) on thermal stress distribution in thermal barrier coatings (TBCs) system are studied in the present paper.A typical TBC system is used:air plasma sprayed (APS) Scandia,yttria-stabilized zirconia (ScYSZ) top coat (TC) and NiCrAlY bond coat (BC) deposited on the nickel super-alloy *** behavior of BC oxidation was *** the Numerical model and Finite Element (FE) method were used to analyze the stress *** objective of this study is to provide important information for understanding the failure mechanism of TBCs at least in a qualitative way.

关键词： Sc2O3-Y2O3-ZrO2 thermal barrier coating stress analysis finite element TGO

Activity Enhancement of Vanadium Catalysts with Ultrasonic Preparation Process for the Oxidation of Sulfur Dioxide

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Journal of Natural Gas Chemistry 2003年第2期12卷 139-144页

作者： Zhenxing Chen, Honggui Li, Lingsen Wangstate key laboratory for powder metallurgy, College of Chemistry and Chemical Engineering, central south university, changsha 410083, china state key laboratory for powder metallurgy College of Chemistry and Chemical Engineering Central South University Changsha 410083 China

The effect of ultrasonic cavitations on the activity of vanadium catalysts atlow temperatures for the oxidation of sulfur dioxide, in which refined carbonized mother liquor hadbeen added, was investigated. Twenty minutes were needed to produce obvious cavitations when thecatalyst raw material was treated in the 50 W ultrasonic generator. However, only 10 minutes wouldbe needed in a 150 W ultrasonic generator. The higher the temperature of the wet material, the lesstime was needed to produce cavitations, and the optimal temperature was 60℃. The water content inthe wet material mainly affected the quantity of cavitations. Ls-8 catalyst was prepared usingultrasonic. Its activity for conversion of SO_2 reached to 52.5% at 410℃ and 4.2% at 350℃. Thedifferential thermal analyses indicate that both endothermic peaks and exothermic peaks noticeablyshifted forward compared with Ls catalyst prepared without ultrasonic, and SEM results show auniform pore size distribution for Ls-8 catalyst.

关键词： ultrasonic dispersion vanadium catalyst low temperature activity sulfurdioxide cavitation

Enhancement in Activity of a Vanadium Catalyst for the Oxidation of Sulfur Dioxide by Radio Frequency Plasma During the Preparation Process

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Journal of Natural Gas Chemistry 2003年第3期12卷 195-200页

Radio frequency plasma was used to prepare a vanadium catalyst. The resultsshowed that activating time of the catalyst could be shortened quickly and the catalytic activitywas improved to some extent with the use of plasma. Catalyst Ls-9 was prepared under an optimalcondition of 40 W discharge power, 10 min discharge time and 8 Pa gas pressure. The catalyticactivity was up to 54.7% at 410℃, which was 2.2% higher than that of the Ls-8 catalyst. Only 10 minwas needed to activate the catalyst with plasma, which was 1/9 of the traditional calcination *** Ls-9, both the endothermic as well as the exothermic peaks detected by differential thermalanalysis shifted to higher temperatures obviously, indicating that its crystal phase could melteasily. There existed an apparent endothermic peak at 283℃. SEM photographs showed a uniform sizedistribution. It is inferred that the quadrivalent vanadium compound may exist mainly in the form ofVOSO_4.

关键词： plasma activation dispersion vanadium catalyst low-temperature activity