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湖南大学学报（自然科学版） 2009年第S1期36卷 115-118页

作者： CHENG Bo1,2.DU Kai1,ZHANG Xiao-song1,YANG Liu1(1.school of energy & Environment,Southeast {2.,Nanjing,Jiangsu 2.0096,china 2.school of Construction engineering,Anhui {2. of Technology,Maanshan,Anhui 2.3000,china) school of energy and Environment Southeast University Nanjing 210096 China school of Construction engineering Anhui University of Technology Maanshan 243000 China

A series of experiments were performed on the viscosity of a nanofluid,produced by mixing carbon black and mulsifier OP-10 using ammonia-water with the ultrasonic *** results show that,when adding surfactant separately in low mass concentrations,at first the viscosity of solution decreases sharply compared with that of ammonia-water,then increases with increasing the concentration of *** a certain concentration of surfactant,the viscosity of nanofluids increases with increasing the concentration of *** on Einstein model and Langmuir absorption theory,a new model was summed up for *** with test values,the calculated values on the new model have verified that the model is suitable to predict the viscosity of nanofluids,because the maximum relative error is less than 5%.Nano-particles absorption in the nanofluids is not only single-molecule layer adsorption,but also multi-layer molecular adsorption and other complicated *** the new model,only based on single-molecule layer adsorption theory of Langmuir,is not fully in line with the real circumstances.

关键词： nanofluid viscosity surfactant absorption

Genetic Optimization Algorithm of PID Decoupling Control for VAV Air-Conditioning System

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Transactions of Tianjin university 2009年第4期15卷 308-314页

作者：王江江安大伟张春发荆有印 school of energy and Power {2. North China Electric Power University school of Environment science and {2. Tianjin University

Variable-air-volume (VAV) air-conditioning system is a multi-variable system and has multi coupling control loops. While all of the control loops are working together, they interfere and influence each other. A multivariable decoupling PID controller is designed for VAV air-conditioning system. Diagonal matrix decoupling method is employed to eliminate the coupling between the loop of supply air temperature and that of thermal-space air temperature. The PID controller parameters are optimized by means of an improved genetic algorithm in floating point representations to obtain better performance. The population in the improved genetic algorithm mutates before crossover, which is helpful for the convergence. Additionally the micro mutation algorithm is proposed and applied to improve the convergence during the later evolution. To search the best parameters, the optimized parameters ranges should be amplified 10 times the initial ideal parameters. The simulation and experiment results show that the decoupling control system is effective and feasible. The method can overcome the strong coupling feature of the system and has shorter governing time and less over-shoot than non-optimization PID control.

关键词： genetic algorithm decoupling control PID control variable air volume air-conditioning system

Effect of Nanophase on the Nucleation of Intragranular Ferrite in Microalloyed Steel

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Journal of Wuhan university of Technology(Materials science) 2010年第2期25卷 228-233页

作者：李新城 Advanced Forming Technology Institute Jiangsu University

MnS, MnS＋V（C, N） complex precipitates in micro-alloyed ultra-fine grained steels were precisely analyzed to investigate the grain refining mechanism. The experimental results shows that MnS, MnS＋V（C, N） precipitates provide nucleation center for Intra-granular ferrite （IGF）, so that refined grain remarkably. Moreover, substructures such as grain boundary, sub-boundary, distortion band, dislocation and dislocation cell in austenite increased as the deformation energy led by heavy deformation at low temperature （deformation temperature≤800 ℃, deformation quantity≥50%）. As a result, V（C, N） nanophase precipitated at these substructures, which pinned and stabilized substructures. The substructures rotated and transformed into ultra-fine ferrite. 2. nm-50 nm were the best grain size range of V（C, N） as it provided nucleating center for intragranular ferrite. The grain size of V（C, N） were less than 30 nm in the microalloyed steels that with volume ratio of ultra-fine ferrite more than 80% and grain size less than 4 μm.

关键词： intra-granular ferrite (IGF) vanadium MnS nanophase substructure

Optimization of Regulation Valve Location for Heating System

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湖南大学学报（自然科学版） 2009年第S1期36卷 88-90页

作者： LIU Ling-ling,CHEN Hong-bing,LI De-ying(school of Environment and energy {2.,Beijing university of Civil {2. and Architecture,Beijing 100044,china) school of Environment and energy {2. Beijing University of Civil Engineering and Architecture Beijing 100044 China

This paper mainly studied how to determine the best location of the self-operated flow control valve at the heating system *** the location of regulating valve directly affects the pipe network performance,the simulation and analysis of pressure change in heating system was carried out with Computational Fluid Dynamics(CFD)*** study shows the best location of regulating valve varies with the change of the supply and return pipe length when the heating area of each user is small,and when the heating area of each user is large(2.000 000～3 000 000 m2.,the best location is on the supply pipe.

关键词： regulating valve optimization CFD simulation

Wear characteristics of spheroidal graphite roll WC-8Co coating produced by electro-spark deposition

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Rare Metals 2010年第2期29卷 174-179页

作者： WANG Jiansheng, MENG Huimin, YU Hongying, FAN Zishuan, and SUN Dongbai school of Materials science and {2., university of science and Technology Beijing, Beijing 100083, china school of Materials science and {2. University of Science and Technology Beijing Beijing China

Electro-spark deposition（ESD） was adopted for preparing high property coatings by depositing WC-8Co cemented carbide on an spheroidal graphite roll *** microstructure and properties of the coating were investigated by X-ray diffraction（XRD）, scanning electron microscopy（SEM） with energy dispersive X-ray（EDX） and ball-disc configuration wear *** results show that nanosized particles and amorphous structures prevail in the coating which is metallurgically bonded to the *** microstructures of the transition zone include columnar structure and equiaxed *** primary phases of the coating contain W2., W6C2.54, Fe3W3C, and *** results of abrasive test show that the coating has low friction coefficients（μaverage = 0.18） and the wear mechanisms are mainly abrasive wear, fatigue wear, and oxidation *** maximum microhardness value of the coating is about 17410 N/*** study reveals that the electro-spark deposition process has better coating quality and the coating has high wear resistance and hardness.

关键词： electro-spark deposition WC/Co coatings wear resistance microstructure

Effects of Sb,Sm, and Sn additions on the microstructure and mechanical properties of Mg-6Al-1.2.-0.9Nd alloy

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Rare Metals 2009年第5期28卷 516-522页

作者： LI Kejie LI Quanan JING Xiaotian CHEN Jun ZHANG Xingyuan school of Materials science and {2. Xi ＇an University of Technology Xi ＇an 710048 China school of Materials science and {2. Henan Universiry of Science and Technology Luoyang 471003 China

The microstructure and mechanical properties of Mg-6Al-1.2.-0.9Nd magnesium alloy with Sb, Sm, or Sn addition were investigated through X-ray diffraction （XRD）, optical microscopy （OM）, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. The results show that small amounts of Sb, Sm, and especially Sn can refine the grains of the alloy. High melting point Sb3Y5, Al2.m, and Nd5Sn3 intermetallic compounds can be formed respectively when Sb, Sm, and Sn are added to the alloy. Sb and Sm can improve the tensile strength of the alloy at ambient and elevated temperatures. The tensile strength of the alloy with Sm addition is the highest at 2.3 and 42. K. However, the tensile strength of the alloy with Sn addition is the highest at 448 K.

关键词： magnesium alloys mechanical properties microstructure Sb Sm Sn

Thermal Comfort in Waiting Room at Railway Station in Cold Region in china

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湖南大学学报（自然科学版） 2009年第S1期36卷 66-70页

作者： MA Wei-wu,CHEN Qian-zhou,ZHOU Jie-min,SHI Xiang-nan,LI Li-qing,WANG Chao,CHEN Zhi-ya(1.school of energy {2. and engineering,Central South university,Changsha,Hunan 410083,china 2.Department of Mechanical engineering,Purdue university,Calumet,Hammond 4632.,USA 3.school of Traffic and Transportation engineering,Central South university,Changsha,Hunan 410083,china) school of energy {2. and engineering Central South University Changsha 410083 China Department of Mechanical engineering Purdue University Calumet Hammond 46323 United States school of Traffic and Transportation engineering Central South University Changsha 410083 China

A field study and analysis about the thermal comfort was carried out in the waiting room at Beijing West Rail Station in Chinese cold ***' TSV(thermal sense vote)was obtained using statistical method on the basis of more than 1 2.0 *** linear regression between TSV and indoor temperature indicates that thermal neutral temperature is 2..2.℃.According to the percentage of satisfaction among all passengers under different indoor temperatures,the acceptable temperature range in the waiting room is 2..2.30.2..It is also found that passengers' temporary stay should be taken into consideration for the thermal comfort ***' TSV is not a constant value after they enter the waiting *** fact,ΔTSV increases as passengers are waiting for the train,and the growing rate is dependent on indoor-outdoor temperature *** greater the temperature difference,the faster ΔTSV *** last,a linear regression between indoor comfortable temperature and outdoor temperature was generated as the adaptive comfort model.

关键词： waiting room thermal comfort adaptive comfort model

A study on methane coupling to acetylene under the microwave plasma

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science china Chemistry 2010年第1期53卷 231-237页

作者： SHEN ChangSheng1,SUN YongZhi1,SUN DeKun2.& YANG HongSheng1 1State Key Laboratory of Millimeter Waves school of Electronic science and {2.,Southeast university,Nanjing 2.0096,china 2.0} of Chemistry and Chemical {2.,Nanjing university,Nanjing 2.0093,china State Key Laboratory of Millimeter Waves school of Electronic science and {2. Southeast University Nanjing China school of Chemistry and Chemical engineering Nanjing University Nanjing China

By optimizing the microwave chemistry reactor made of the rectangular waveguide resonator,the methane conversion(the maximum 93.7%),the C2.hydrocarbon yield(the maximum 91.0%) and the acetylene yield(the maximum 88.6%) were all greatly increased under the microwave ***,for the optimal reactor,the change of the methane conversion and the C2.hydrocarbon yield is little within the range of the pressures in the *** C2.hydrocarbon is mainly made up of acetylene,and the selectivity for acetylene is above 90%.energy yield and space time yield of acetylene are also *** emission spectroscopy(OES) was adopted for the diagnosis of methane coupling to acetylene under microwave *** excited species(CH,C2.H2.Hα) were detected in the spectra range of 300-750 *** on the products and the excited species,the reaction mechanism of methane coupling under microwave plasma was investigated,using the thermodynamics and kinetics of the chemical reaction.

关键词： microwave plasma methane acetylene

Influence of Molecular Weight of PEO on Performance of Quasi-solid-state Dye-sensitized Solar Cells

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Journal of Wuhan university of Technology(Materials science) 2010年第2期25卷 218-222页

作者：沈小林 school of Materials science & {2. Xi’an Jiaotong University

Quasi-solid-state dye-sensitized solar cells （DSCs） were prepared using gel electrolyte gelated by poly（ethylene-oxide）（PEO） with different molecular weight. With the increase in PEO molecular weight, the short circuit current densities （Jsc） increase significantly, which is related to the increase in I - diffusion due to the increase in free volume of gel electrolyte. However, only a slight increase in open voltage （Voc） is observed, which is explained by the decrease in dark current arising from the reduction of triiodide （I3^-） by conduction band electrons.

关键词： dye-sensitized solar cell poly(ethylene oxide) gel electrolyte molecular weight