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Modeling and Assessment of Buoyancy-Driven Stratified Airflow in High-Space Industrial Hall

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湖南大学学报（自然科学版） 2009年第S1期36卷 19-22页

作者： WANG Han-qing1,2,CHEN Ke1,HU Jian-jun1,3.KOU Guang-xiao2,WANG Zhi-yong2(1.School of Energy science and engineering,Central South university,{3.,hunan 410083.china 2.Department of Civil engineering,hunan university of Technology,Zhuzhou,hunan 412008,china 3.School of Mechanical engineering,Purdue university,West Lafayette,USA) School of Energy science and engineering Central South University Changsha 410083 China Department of Civil engineering Hunan University of Technology Zhuzhou 412008 China School of Mechanical engineering Purdue University West Lafayette United States

In industrial environment,heat sources often are contaminant sources and health threatening contaminants are mainly passive,so a detailed understanding of airflow mode can assist in work environment hygiene measurement and *** paper presented a numerical investigation of stratified airflow scenario in a high-space industrial hall with validated commercial code and experimentally acquired boundary *** upon an actually undergoing engineering project,this study investigated the performance of the buoyancy-driven displacement ventilation in a large welding hall with big components *** results have demonstrated that stratified airflow sustained by thermal buoyancy provides zoning effect in terms of clean and polluted regions except minor stagnant eddy *** competition between negative buoyant jets from displacement radial diffusers and positive buoyant plume from bulk object constitutes the complex transport characteristics under and above stratification ***,downdraft and turbulent eddy motion complicate the upper mixing zone,but the exhaust outlet plays a less important role in the whole field *** the corresponding suggestions concerning computational stability and convergence,further improvements in modelling and measurements were given.

关键词： modelling buoyancy-driven large enclosure industrial ventilation

Thermodynamic properties of under-cooled silver melts

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science china(Physics,Mechanics & Astronomy) 2010年第1期53卷 76-80页

作者： ZHU YuYing 1 , LI Qiang 1,2,3. WANG Ge 1 , JING Qin 2 , WANG Xu 1 , GAO Ying 3.& GAO JingNa 3.1 Department of Mechanical engineering, Yanshan university, Qinhuangdao 066004, china 2 Key Laboratory of Metastable {3. science & Technology, Yanshan university, Qinhuangdao 066004, china 3.Department of {3. science & engineering, Hebei university of science and Technology, Shijiazhuang 050018, china 1. Department of Mechanical engineering Yanshan University Qinhuangdao 066004 China2. Key Laboratory of Metastable Materials Science & Technology Yanshan University Qinhuangdao 066004 China3. Department of Materials Science & Engineering Hebei University of Science and Technology Shijiazhuang 050018 China

Differential scanning calorimeter technique combined with the traditional fluxing treatment was used to investigate the specific heat and related thermodynamic properties of under-cooled pure silver melts. The specific heat of the under-cooled melt showed a linear dependence on the temperature in the range of the obtained under-cooling from 0 to 198 K. The related thermodynamic properties of silver, such as the entropy change, the enthalpy change and the Gibbs free energy difference between the under-cooled melt and the solid phase, were derived from the measured specific heat. The relations between the temperature and the thermal diffusion or the thermal conductivity of the under-cooled melt were analyzed respectively.

关键词： under-cooled silver melts specific heat thermodynamic properties

Effect of Fe metal on the growth of silicon oxide nanowires

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International Journal of Minerals,Metallurgy and materials 2009年第3期16卷 317-321页

作者： Wei-long Liu1), Shu-huei Hsieh1), Ching He Chen2), and Wen-jauh Chen3. 1) Department of materials science and engineering, Formosa {3., Yunlin 63., china Taipei 2) Department of materials engineering, Pingtung {3. of science and Technology, Pingtung 912, china Taipei 3. Graduate School of materials science, Yunlin {3. of science and Technology, Yunlin 63., china Taipei [a]Department of materials science and engineering Formosa University Yunlin 632 China Taipei [b]Department of Materials Engineering Pingtung University of Science and Technology Pingtung 912 China Taipei [c]Graduate School of Materials Science Yunlin University of Science and Technology Yunlin 632 China Taipei

Silicon oxide (SiOx) nanowires are generally grown on Si substrate under the catalysis of Au in N2 atmosphere at elevated temperatures. Because the price of Au metal is quite high, Fe metal is then used to replace a part of Au for catalyzing the growth of SiOx nanowires. The results show that the Fe film can be used as the diffusion barrier of Au. SiOx nanowires are grown on Au/Fe/Si substrate at 103.°C. Under the catalysis of Fe/Au, the efficiency for the growth of SiOx nanowires is promoted.

关键词： silicon oxide nanowires Au catalyst Fe substitution Si substrate

Synthesis of vertically aligned carbon nanotube arrays on silicon substrates

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science china(Technological sciences) 2004年第5期47卷 616-624页

作者： ZHENG Ruiting1, CHENG Guoan1, PENG Yibin1, 2, ZHAO Yong1, 3. LIU Huaping1 & LIANG Changlin1 1. Key Laboratory of Radiation Beam Technology and materials Modification of Ministry of Education, Department of materials science and {3., Beijing Normal university, Beijing 100875, china 2. School of science, Civil Aviation university of china, Tianjin 3.03.0, china 3. Department of Physics, Nanchang university, Nanchang 3.0047, china Correspondence should be addressed to Zheng Ruiting 1. Key Laboratory of Radiation Beam Technology and materials Modification of Ministry of Education Department of Materials Science and Engineering Beijing Normal University 100875 Beijing China 2. School of science Civil Aviation University of China 300300 Tianjin China 3. Department of Physics Nanchang University 330047 Nanchang China

The growth of well-aligned carbon nanotube (CNT) arrays using a heat chemical vapor deposition system on silicon substrates is reported. The growth properties of CNT arrays are studied as a function of synthesis conditions. It is found that 750°C and 10 nm Fe film are suitable conditions for the growth of well-aligned CNT arrays. CNT arrays with a uniform diameter, thick tube wall and firm cohesion to the Si substrate can be grown for C2H2 concentration of 27%. Based on the experiment, the processes of improving the alignment of CNT arrays and cohesion between CNT arrays and Si substrates are discussed.

关键词： carbon nanotubes, vertically aligned, silicon substrate, chemical vapor deposition.

Mass Concentration of Particles (PM10) in Urban Environment of changsha,china

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湖南大学学报（自然科学版） 2009年第S1期36卷 5-9页

作者： TANG Meng,DENG Qi-hong,WANG Qi(School of Energy science & engineering,Central South university,{3.,hunan 410083.china) School of Energy science and engineering Central South University Changsha 410083 China

Continuous measurement of ambient PM10 was performed by TEOM at a university campus for about one year from 20 November 2007 to 29 October 2008 in changsha city of hunan *** PM10 and PM2.5 concentration were measured by DustTrak simultaneously in order to describe the difference in concentration level and daily variations of particle mass concentration between different seasons,and to survey the influence of ambient particle on indoor air *** the survey period,the annual average PM10 concentration was found to be 117.63.μg/m3.with a mean value 121.88 μg/m3.in winter and 111.50 μg/m3.in *** temporal trend changed quickly from time to time,and the peak values were found in rush hours and in the *** PM10 showed a good correlation with indoor PM10 and outdoor PM2.5 but not with indoor *** results showed that PM10 was influenced by local source(such as traffic or fuel burning)and regional *** correlation analysis has shown that ambient PM10 contributes substantial fraction to indoor PM10 but not to indoor PM2.5,which indicates other source may exist in the indoor environment.

关键词： particle mass concentration human activity relationship

Analysis of the carbon source for diamond crystal growth

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Chinese science Bulletin 2008年第6期53卷 937-942页

作者： LI Li1,2, XU Bin2,3.& LI MuSen1,2 1 School of materials science & engineering, Shandong {3., Jinan 250061, china 2 Shandong engineering Research Center for Super Hard materials, Zoucheng 273.00, china 3.School of materials science & engineering, Shandong Jianzhu {3., Jinan 250101, china School of materials science & engineering Shandong University Jinan China Shandong engineering Research Center for Super Hard materials Zoucheng China School of materials science & engineering Shandong Jianzhu University Jinan China

The lattice constants of diamond and graphite at high pressure and high temperature (HPHT) were calculated on the basis of linear expansion coefficient and elastic constant. According to the empirical electron theory of solids and molecules (EET), the valence electron structures (VESs) of diamond, graphite crystal and their common planes were calculated. The relationship between diamond and graphite structure was analyzed based on the boundary condition of the improved Thomas-Fermi-Dirac theory by Cheng (TFDC). It was found that the electron densities of common planes in graphite were not continuous with those of planes in diamond at the first order of approximation. The results show that during the course of diamond single crystal growth at HPHT with metal catalyst, the carbon sources forming diamond structure do not come from the graphite structure directly. The diamond growth mechanism was discussed from the viewpoint of valence electron structure.

关键词：钻石晶体生长石墨碳源价电子结构

Effects of binders on the performance of electric double-layer capacitors of carbon nanotube electrodes

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Progress in Natural science:materials International 2005年第5期15卷 453-457页

作者： LI Chensha1*, WANG Dazhi1, ZHANG Baoyou2, WANG Xiaofeng1, CAO Maosheng3. and LIANG Ji1(1. Department of Mechanical engineering, Tsinghua university, Beijing 100084, china 2. Center for Analysis and Measurement, Harbin Institute of Technology, Harbin 150001, china 3. School of Material science and engineering, Tsinghua university, Beijing 100084, china) Department of Mechanical engineering Tsinghua University Beijing 100084 China Center for Analysis and Measurement Harbin Institute of Technology Harbin 150001 China School of Material science and engineering Tsinghua University Beijing 100084 China

Polarizable electrodes of electric double layer capacitor (EDLCs) were made from carbon nanotubes. Effects of different binders, which are phenolic resin (PF) and polytetrafluoroethylene (PTFE), on the properties of polarizable electrodes are studied. Results indicate that the microstructure, pore size distribution and specific capacitance of the electrodes with PTFE binder are superior to those electrodes with PF binder after carbonization. The suitable binder (PTFE) for carbon nanotubes electrodes is proposed.

关键词： carbon nanotubes electric double-layer capacitors phenolic resin polytetrafluoroethylene.

HOMOGENIZATION TREATMENT OF Mg-Al-Zn(MM)MAGNESIUM ALLOY INGOTS

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Acta Metallurgica Sinica(English Letters) 2002年第6期15卷 545-550页

作者： K. Yu and W.X. LiCollege of materials science and engineering, Central South {3., changsha 410083. china College of materials science and engineering Central South University

The Mg-Al-Zn series AZ3. and AZ3.+MM alloys are homogenized at 673. 723.and 753. respectively. The hardness of alloy ingots at different heat-treated states is measured and the micro structures are observed. The optim... 详细信息

关键词： magnesium alloy homogenization diffusion

Effect of Trace Sc and Zr on the Mechanical Properties and Microstructure of A1 Alloy 2618

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Journal of materials science & Technology 2000年第4期16卷 416-420页

作者： Kun YU, Songrui LI and Wenxian LI (Department of materials science and engineering, Central South {3. of Technology, changsha 410083. china) Department of materials science and engineering Central South University of Technology Changsha 410083 China

An experimental 2618(Al-Cu-Mg-Fe-Ni) alloy added with trace Sc and Zr was prepared by ingot metallurgy (IM) method. The aging behavior of the alloy was studied by Vickers hardness measurement at 200℃ and 3.0℃. and the tensile properties of alloy specimens were measured at 20℃, 200℃, 250℃ and 3.0℃. The microstructure was observed by using optical microscope, SEM and TEM. It was found that the addition of Sc and Zr to 2618 alloy resulted in a primary Al_3.Sc,Zr) phase which could refine the grain because it acts as nuclei of heterogeneous crystallization in the melt during solidification. The secondary Al_3.Sc,Zr) particles were full coherent with matrix and had obvious precipitation hardening effect. They also made the S' phase precipitate more homogeneous. So the strength of alloy increases at both ambient and elevated temperatures without a decrease of ductility. The ductile fracture of alloy occurs by microvoid nucleation, growth and coalescence, so the microvoid coalescence is the dominant fracture mechanism.

关键词： Sc Zr Effect of Trace Sc and Zr on the Mechanical Properties and Microstructure of A1 Alloy 2618