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湖南大学学报（自然科学版） 2009年第S1期36卷 96-101页

作者： TANG Wen-wu1,2.WANG Han-qing1,2.1.School of Energy Science and engineering,Central South University,Changsha,hunan 410083,{2. 2.School of civil engineering,hunan University of technology,zhuzhou,hunan 412.08,{2.) School of Energy Science and engineering Central South University Changsha 410083 China School of civil engineering Hunan University of Technology Zhuzhou 412008 China

This paper presented an entropy evaluation method for the influences of condense heat recovery system on the *** at the damage of the condense heat to the environment,an entropy of resource loss and an emission entropy from the condense heat recovery system in the air conditioning refrigerating machine were *** the evaluation of the entropies,we developed a new algorithm for the parameter identification,called the composite influence coefficient,based on the Least Squares Support Vector Machine *** simulation,the numerical experiments shows that the Least Squares Support Vector Machine method is one of the powerful methods for the parameter identification to compute the damage entropy of the condense heat,with the largest training error being-0.02.(the relative error being-3.56%),and the biggest test error being 0.015(the relative error being 2.5%).

关键词： air-conditioning refrigerating machine condense heat entropy evaluation LS-SVM

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,Changsha,hunan 410083,{2. 2.department of civil engineering,hunan University of technology,zhuzhou,hunan 412.08,{2. 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 {2. 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

Influence of Calcium Sulfate State and Fineness of Cement on Hydration of Portland Cements Using Electrical Measurement

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Journal of Wuhan University of technology(Materials Science) 2006年第4期21卷 141-145页

作者：魏小胜 department of civil {2. Huazhong University of Science and Technology Wuhan 430074 China

The influence of calcium sulfate state and fineness of cement on hydration of Portland cement was studied using electrical resistivity measurement. The bulk resistivity curve of the paste from the abnormal cement mainly with hemihydrate had a characteristic abnormal peak and rapid increase in early period. The resistivity measurement technique can be used to discriminate abnormal setting. For normal cement with gypsum, the increase in fineness of the Portland cement decreases the minimum resistivhy due to a higher ionic concentration and increases the 2. hour resistivity due to a reduction in macroscopic pore size. The setting time, compressive strength, pore structure of pastes made from different cements were carried out to compare the influence of water to cement ratio, calcium sulfate state and fineness. It is found that the electrical and mechanical properties are strongly affected by the initial porosity, the presence of hemihydrate or gypsum, and the fineness of cement.

关键词： false setting electrical resistivity fineness hydration

Analysis on cohesive crack opening displacement considering the strain softening effect

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Science china(Physics,Mechanics & Astronomy) 2006年第1期49卷 88-101页

作者： WANG Limin1, XU Shilang2.& ZHAO Xiqiang3 1. Mechanics department, Shandong University of technology, Zibo 2.5049, {2. 2. civil engineering department, Dalian University of technology, Dalian 11602., {2. 3. Mathematics department, Ocean University of {2., Qingdao 2.6071, {2. Mechanics department Shandong University of Technology Zibo 255049 China civil engineering {2. Dalian University of Technology Dalian 116024 China Mathematics department Ocean University of China Qingdao 266071 China

In order to investigate the crack propagation in quasi-brittle materials like rock, ceramic and concrete, Hillerborg and his co-researchers abstracted the fracture process zone in front of a stress free crack in terms of a “fictitious crack zone”. On the fictitious crack zone, cohesive stresses distribute following a given softening relationship of stress vs. crack opening. Based on the polynomial or power series expression of cohesive crack opening displacement, the relationship of the cohesive stress vs. the crack opening displacement is established using elastic theory and integral equation, and some unknown physics variables are obtained using variation approach. The calculation results gained in this paper are close to the experimentally test ones.

关键词： cohesive crack, softening, dissipation work, variation approach.

Dynamic Properties of Concrete under Severe Environmental Condition

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Journal of Wuhan University of technology(Materials Science) 2010年第5期25卷 877-882页

作者：闫东明 department of Hydraulic and Environmental engineering Zhengzhou University department of civil and Hydraulic {2. Dalian University of Technology

Exposure to environmental conditions can significantly influence the mechanical behavior of concrete structures in civil engineering. In this study, the effect of environmental factors, such as moisture and temperature, on the strain-rate sensitivity of concrete mixtures was systematically investigated. The strain rate varied from 10^-5s^-1 to 10^-2.^-1. From the investigation it was concluded that moisture content had a significant influence on the strain-rate sensitivity of concrete. With regard to concrete with low moisture content, temperature had little influence on the rate-dependent behavior; while for fully saturated specimens, a significant influence was observed. These phenomena were attributed to the meso-scale bonding properties of the concrete matrix. Equations were derived to characterize the ultimate strength increment of concrete with strain rate under different environmental conditions. An explanation to the dynamic failure mechanisms of concrete based on the experimental findings was proposed.

关键词： concrete strain rate moisture content temperature failure mechanism

Electrical Measurement to Assess Hydration Process and the Porosity Formation

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Journal of Wuhan University of technology(Materials Science) 2008年第5期23卷 761-766页

作者：魏小胜 department of civil {2. Huazhong University of Science and Technology

The change of electrical resistivity with time at early ages was used to investigate the hydration process and the porosity development. Porosity reduction process of cement-based materials hydration was developed by a proposed method. The porosity reduction is fast at the setting period. The results find that the pore discontinuity occurs faster at lower water/cement ratios than at higher water/cement ratios which is similar to the results of the Percolation method.

关键词： electrical resistivity hydration setting time percolation

A two-dimensional study on natural convection and heat transfer in the enclosure with heat transfer and radiation coupled in natural convection

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Science china(Technological Sciences) 2010年第4期53卷 991-999页

作者： ZHAN NaiYan1,2.YANG Mo1 & XU PeiWei2.1 College of Power engineering,University of Shanghai for Science and technology,Shanghiai 2.0093,{2. 2.department of Environmental engineering,Jilin Architectural and civil engineering Institute,Changchun 13002.,{2. 1. College of Power engineering University of Shanghai for Science and Technology Shanghiai 200093 China2. Department of Environmental Engineering Jilin Architectural and Civil Engineering Institute Changchun 130021 China

Numerical investigation using SIMPLE algorithm with QUICK scheme for natural convection and heat transfer in the enclosure bounded by a solid wall and with heat transfer and radiation coupled in natural convection has been *** various parameters are:Rayleigh number(from 103 to 105),dimensionless conductivity of bounding wall(from 0 to 100),dimensionless wall thickness(from 0 to 0.6) and radiation emissivity of all surfaces(from 0 to 1).The results suggest that flow and heat transfer are influenced by *** is a dominant action on flow and heat *** increase of the thermal conductivity of wall,flow and heat transfer turn *** temperature distribution changes *** the thermal conductivity of wall is over a certain critical number,the increasing trend of flow and heat transfer may *** increase of enclosure wall thickness,flow and heat transfer turn *** the enclosure wall thickness is over a certain critical number,the flow and heat transfer will turn slow.

关键词： conduction natural convection radiation couple numerical simulation

The Compatibility of Polycarboxylate-Type Superplasticizers with Cement

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Journal of Wuhan University of technology(Materials Science) 2005年第3期20卷 95-98页

作者：李崇智 department of civil {2. Beijing Institute of Civil Engineering and Architecture

Four polycarboxylate- type （ PC ） superplasticizers of different functional groups were used ; their dispersing and retaining behaviors were analyzed through ZETA potential measurement, mini-slump test of cement paste and performance test of concrete. The experimental results show that the dispersing and flow-retaining ability of PC was determined by two factors of anionic groups and nonionic groups ： the density of anionic groups - COO^- or - SO3^- acted on the electronic repulsive force. and the length and proportion of nonionic graft groups of PEO in PC chemical stracture affected the steric effect. The compatibility between PC superplasticizers and cement mainly depended on the type of PEO groups ; furtlwrmore, adding mineral powders is good to the compatibility for high performance concretes （ HPCs ）.

关键词： PC superplasticizers cement compatibility

Effects of Ultrasonic Field on Microstructures and Properties of Semi-solid AZ91D Magnesium Alloy

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Journal of Wuhan University of technology(Materials Science) 2010年第4期25卷 555-560页

作者：陈国平 Mechanical engineering Institute Hunan Industry University(Zhuzhou) Mechanical and Electrical engineering Institute Nanchang University

The microstructure distribution rule of semi-solid AZ91D alloy treated by ultrasonic was researched, and mechanical properies of specimens before and after ultrasonic treatment were investigated ***-solid AZ91D melt specimens were processed by ultrasonic under different powers, and its microstructures and mechanical properties at different sampling points in specimens were obtained. The experimental results show that the microstructure of AZ91D alloy at different sampling points under the same ultrasonic power is different in grain size and shape, and there is also great difference among their microstructures at the same sampling point under different ultrasonic powers. AZ91D alloy treated by ultrasonic can obtain increment in both tensile strength and plasticity. Under same ultrasonic power, mechanical properties of specimen at different sampling points have obvious difference, and regularity for change of mechanical properties everywhere is similar to regularity for change of grain size and shape everywhere.

关键词： magnesium alloy AZ91D ultrasonic treatment semi-solid structure distribution rule

Chuetsu earthquake damages in Niigata County of Japan

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Progress in Natural Science:Materials International 2007年第10期17卷 1255-1259页

作者： Li Hongnan1, Zhao Yangang2.and Wang Guoxin1(1. State Key Laboratory of Coastal and Offshore engineering, Dalian University of technology, Dalian 11602., {2. 2. department of civil and Architectural engineering, Nagoya Institute of technology, Nagoya 466-8555, Japan) State Key Laboratory of Coastal and Offshore engineering Dalian University of Technology Dalian 116024 China department of civil and Architectural {2. Nagoya Institute of Technology Nagoya 466-8555 Japan

An Earthquake ML=6.8 occurred on October 2., 2.04 in Chuetsu area of Niigata County in Japan, which caused 40 people dead, more than 4500 people injured and 1000000 people homeless; nearly 140000 buildings were damaged or collapsed. The estated total loss of this earthquake was about 3000 billions Yen. In this paper, we investigate the Chuetsu earthquake damage from different aspects, including the seismic outline, seismicity, intensity distribution, wave feature, damage analyses, and economic losses. Finally, experiences and lessons from the earthquake damage are given. The content in this paper may be a reference for structural seismic design and code modification.

关键词： Chuetsu earthquake seismic damage Niigata province in Japan.