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Sol-gel Preparation and Infrared Radiation Property of Boron-substituted Cordierite Glass-ceramics

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Journal of Materials science & Technology 2010年第5期26卷 445-448页

作者： Shuming Wang and Fenghua Kuang School of Materials science and engineering,university of science & Technology {4.,{4. 100083,china [a] School of Materials science and engineering university of science & Technology beijing beijing 100083 china

Boron for aluminum substitution in the cordierite structure has been examined by sol-gel preparation of different samples along the compositional junction Mg2Al4.xBxSi5O18 with x=0,0.5,1,*** increasing the x value from 0 to 1.5 the crystallization behavior changed *** amount B2O3 doping can promote the sintering of amorphous cordierite gel,effectively restrain the precipitation of μ-cordierite and enhance the crystallization of α-*** substitution of B3＋ for Al3＋ in cordierite crystal structure can effectively improve the near-infrared spectral emissivity of this cordierite based glass-ceramics.

关键词： Sol-gel Glass-ceramics Infrared radiation B3+ substitution Solid solution

Characteristics of Ore-Forming Fluids of Gold Deposits in Daqingshan District,Inner Mongolia,china

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International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 77-82页

作者： Jiuhua Xu YulingXie Dayi Qian Rufu Dine Jianping Li (Resource engineering School, university of science and Technology Beijha beijing 100083, {4.) ({4. university of Geosciences, beijing 100083, {4.) Resource engineering School University of Science and Technology Beijing Beijing 100083 China china university of Geosciences Beijing 100083 China

***-weststrikingductileshearzonewithinagreelt,***:(1)pyrite-quartz,(2)quartz-Pyrite,(3)polymetallicsulfidesand(4.***-bearingveinsarenativegold,electrum,pyrite,chalcopyriteandgalena,buttheganguemineralsaremainlyquartz,secondarilysericite,***,silicification,***-formingfluidswerelowinsalinitieandhighinCO2content,MeasuredδDoffluidinclusionsinquartzfromtheoreveinsrangesfrom-65‰to-104.,butδ18Oquartzfrom10.0‰to12.8‰.Thesedatashowthatthewaterinhydrothermalfluidprecipitatingtheorebodiescouldhavebeenmainlymagmaticwaterandmetamorphicwaterbutlocalmeteoricwatermighttakepartinthelatemineralization.δ13Cfromfl

关键词： fluid inclusions isotope composition gold deposit Daqingshan area

High Resolution Electron Microscopy Observations of Structural Changes in Iron Nitride Films Annealed in Vacuum

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Journal of Materials science & Technology 1997年第2期13卷 123-126页

作者： Shengkai GONG Huibin XU (Dept. of Materials science and engineering, beijing university of Aeronautics and Astronautics,{4., china) Dept. of Materials science and engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

Iron-nitride films were prepared by reactive sputtering, and the effect of annealing treatment on the structures was investigated by means of in-situ electron microscopy and high resolution electron microscopy (HREM). As-deposited films were observed to be a mixed structure of a few ultrafine epsilon-Fe2-3N particles existing in the amorphous matrix. it was found that the structure-relaxation in the amorphous occurred at 4.3 K, and the ultrafine grains began to grow at the higher annealing temperatures. The transition of the amorphous to epsilon-Fe2-3N was almost completed at 673 K. It is considered that the formation of the ideal epsilon-Fe3N is originated from the ordering of the nitrogen atoms during the annealing in vacuum. On the other hand, gamma'-phase (Fe4.) was seen to precipitation of epsilon-phase at 723 K. Two possible modes are proposed in the precipitation of gamma'-phase, depending on the heating rate and crystallographic orientation relationships, i.e. [121](epsilon)//[001](gamma), (2(1) over bar0$)(epsilon)//(110)(gamma) and [100](epsilon)//[110](gamma), (001)(epsilon)//(111)(gamma). In addition, alpha-Fe particles were observed to form from the gamma'-phase at high temperatures. We assumed that these structural changes are due to the diffusion of nitrogen and iron atoms during the annealing, except for the case of the precipitation of the gamma'-phase as depicted above. The results obtained in this work are in a good agreement with the assumption.

关键词： Figure High Resolution Electron Microscopy Observations of Structural Changes in Iron Nitride Films Annealed in Vacuum

Hot Corrosion of Iron in the Presence of Salt Mixture Deposit Containing NaCl and V_2O_5 at 600℃

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Journal of Materials science & Technology 1996年第6期12卷 445-451页

作者： Lingchuan LI (Dept. of Materials science and engineering, Tsinghua university beijing 100084. {4.)Rizhang ZHU (Dept. of Surface science and Corrosion engineering, university of science and Technology beijing, beijing 100083, {4.)(To whom correspondenc Dept. of Materials science and engineering 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 Na2SO4.Na2SO4.mixed with NaCl and Na2SO4.mixed with V2O5 in a combustion gas at 600℃. The additions of NaCl to Na2SO4.and of V2O5 to Na2SO4.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 Na2SO4.mixed with V2O5 and the gas formed (Na2O)xV2O4.V2O5)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

Nonequilibrium Thermodynamic and Dissipative Structure Mechanism of Fluidized Beds

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International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 90-93页

作者： Maozhan Qi Li Wang Xuezi Ni (Mechanical engineering School, university of science and Technology beijing,{4., china) Mechanical engineering School University of Science and Technology Beijing Beijing 100083 China

Fluidized beds are nonlinear dynamic systems that exchange mass and energy with outside. They are governed not only byfluid dynamics, but by thermodynamics, especially the second law of thermodynamics as well. According to Prigogine's dissipative structure theory, the following have been concluded: (l) a fixed bed is on thermodynamic blanch, and bubbling, turbulent and fast beds areon the dissipatve structure branches. (2) Entropy in fluidized beds is divided into tWo parts: entropy production and entropy flux. The latter increases with gas velocity and decreases with pressure of the systems. That means the entropy of a system may reduce and the systemwith higher gas velocity behaves as dissipative structure characteristics. (3) For a giVen velocity, a fluidized bed operates stably on thewhole, but it is unstable to local gas-solid phases. The unstable phases are described by fluid dynamic equations, While the minimum ofsystem energy function assures whole stability of the system. (4. A transition criterion of a bubbling bed is derived from Prigogine's stability theory.

关键词： fluidized bed nonequilibrium thermodynamics dissipative structure energy extremum

Effect of SPM Scanning Range on the Micromorphology Parameters

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International Journal of Minerals,Metallurgy and Materials 1998年第1期12卷 36-38页

作者： Libing Liao Suozai Li (School of materials science and engineering, china university of Geosciences, beijing 100083, china) School of Materials science and engineering China University of Geosciences Beijing 100083 China

The surface of a compact disk is analyzed by using SPM and the quantitative micromorphology analysissoftware SPMIAS developed by the author. Images at the same position but with different scanning ranges areobtained under the same experimental conditions. Micromorphology parameters are calculated and compared, andthe relationship between the changing of the scanning range and the changing of micromorphology parameters issummarized.

关键词： Scanning Probe Microscope(SPM) micromorphology micromorphology parameters

Dissolving of Nb and Ti carbonitride precipitates in microalloyed steels

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Journal of university of science and Technology beijing 2003年第5期10卷 78-80页

作者： Wenjin Nie, Shanwu Yang, Shaoqiang Yuan, and Xinlai HeMaterials science and engineering School, university of science and Technology {4., beijing 100083, china Materials science and engineering School University of Science and Technology Beijing Beijing 100083 China

The dissolving behaviour of Nb and Ti carbonitride precipitates inmicroalloyed steels during isothermal holding at 1300℃ was investigated by Transmission electronmicroscopy (TEM) and energy dispersion x-ray spectrum (EDX). It was found that all precipitates inNb-Ti microalloyed steel are (Nb, Ti)(C, N). With holding time increasing, the atomic ratio of Nb/Tiin precipitates decrease gradually. These precipitates still existe even after holding for 4. h at1300℃ while Nb(C, N) precipitates dissolve away in Nb microalloyed steel only after 4.h at the sametemperature. These results show that formation and thermostability of precipitates are considerablyinfluenced by interaction between Nb and Ti.

关键词： dissolving (Nb, Ti)(C, N) TEM EDX

Rheological Behavior of Semi-Solid AZ91D Alloy

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Journal of Materials science & Technology 2004年第5期20卷 580-582页

作者： Weimin MAO, Zisheng ZHEN, Shijian YAN and Xueyou ZHONGSchool of Materials science and engineering, university of science and Technology {4., beijing 100083, china Sch. of Mat. Sci. and Eng. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The rheological behavior and microstructure of semi-solid AZ91D was studied using a Couette type viscometer. The results show that the apparent viscosity of semi-solid AZ91D increases with the cooling rate increasing when it is continuously cooled and mechanically stirred and the empiric relation of the apparent viscosity with the cooling rate and solid fraction at shearing rate 93.7 s-1 is expressed as η=[0.66-0.63e(-ε/3.01)]e(fa/0.14., and with the shearing rate and solid fraction at cooling rate 4./min is shown as η=0.55e(fa/0.11-γ/87.59), as well as the cooling rate and shearing rate have an important effect on the microstructure of the semi-solid AZ91D alloy slurry, and decreasing the cooling rate and increasing the shearing rate are favorable to the nondendritic evolution of the primary grains.

关键词： Rheological behavior Magnesium alloys Semi-solid

ANALYSIS OF DEPOSITED PRODUCTS AND REANODIZED POROUS LUBRICATING FILM ON A1 AFTER(NH_4._2MoS_4.SOLUTION TREATMENT

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Acta Metallurgica Sinica(English Letters) 1993年第8期6卷 102-107页

作者： JIANG Guang WU Yinshun LI Jiuqing LIU Haiping university of science and Technology beijing,beijing,{4. Department of Surface sciences and Corrosion engineering,university of science and Technology beijing,beijing 100083,{4. beijing Univ of science and Technology Beijing China

Observation was carried out of the structure of sulphuric,oxalic or phosphoric film on Al after treatment of reanodizing and electrolytic depositing lubricant in (NH_4._2MoS_4.solution,as well as of the deposited products by means of EMPA,TEM and energy spectro-scopic *** deposited products are mixture of compounds of S and Mo rather than single MoS_2 and most of them dcposited near the surface layer of the *** regular long pores without barrier layer occurred in the film,but the regular fine channels without relation to the structural element parameters of original anodized film were found in the thickened barrier layer of phosphoric *** may be remained as Mo sulphide in the film during heating under Ar protective environment.

关键词： Al anodizing reanodizing lubricating film MoS_2