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Early Age Properties of Cementitious Materials by Electrical Resistivity Measurement

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Journal of Wuhan university of Technology(Materials Science) 2010年第4期25卷 641-644页

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

Three cement pastes were prepared with the fixed water-binder ratio and different fly ash contents. The compression test and electrical resistivity measurement of the paste mixes were conducted during 48 h. The changes of the CH content and the non-evaporable water content in the cement-fly ash hydration systems with time were obtained by the thermal gravimetric analysis. The experimental results show that dilution effect of fly ash as micro-filler is dominant mechanism before 48 h, which appears to decrease in the CH content and the non-evaporable water content, also in compressive strength and electrical resistivity, with the increase of fly ash replacement. The relationships between CH content, non-evaporable water content and electrical resistivity show that electrical resistivity can be the indicators of hydration products CH and non-evaporable water. The correlation of the compressive strength fc and the electrical resistivity ρcan be obtained as fc=8.342.ρ=6.7088 for the period of 48 h. The early age compressive strength can then be predicted by electrical resistivity measurement.

关键词： electrical resistivity fly ash compressive strength hydration

THEORETICAL STUDIES ON MICROBUCKLING MODE OF ELASTIC MEMORY COMPOSITES

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Acta Mechanica Solida Sinica 2010年第1期23卷 20-28页

作者： Zhengdao Wang Zhengfa Li Zhiyuan Xiong Linyun Wang(Department of Mechanics,school of civil {2.,Beijing jiaotong university,Beijing 100044,china) [a] Department of Mechanics School of Civil Engineering Beijing Jiaotong University Beijing 100044 China

Elastic memory composites （EMCs） have great potential applications in future deployable space structures due to their high packaging strain and shape memory characteristics. Microbuckling of compressed fibers is the primary deformation mechanism of such structures to receive a higher packaging strain than that of traditional fiber-reinforced composites. In order to have a better understanding of such deformation mechanism, the microbuckling model of EMC laminates under bending is analyzed firstly. Then the theoretical critical microbuckling parameters are predicted, which are compared with experimental observations and other models.

关键词： elastic memory composite deployable structure microbuckling model

Simplified Computation of Reflective Overpressure in Closed Cuboid Space Due to Internal Explosion

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Transactions of Tianjin university 2010年第6期16卷 395-404页

作者：田力李忠献周清 school of civil {2. Tianjin University Binzhou Urban Planning and Design Institute

A simplified method is proposed for analyzing the overpressure history of an optional point on the walls of a closed cuboid due to its internal optional point-explosion. Firstly, the overpressure histories of all nodes on the walls of a cube with a side-length of 2.m are computed under a reference-charge explosion at each node of its inner space using the LS-DYNA software, and then are collected to form a reference database. Next, with the thought of the isoparametric finite element, an interpolating algori...

关键词： closed cuboid space reference database reflective overpressure charge weight

Experimental Study on the Effect of Cyclic Preloading on the Resistance to Liquefaction of Saturated Loose Sand under Wave Loading

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Journal of Shanghai jiaotong university(Science) 2009年第4期14卷 398-403页

作者：张振东栾茂田金丹郭莹聂影 State Key Laboratory of Coastal and Offshore engineering Dalian University of Technology Institute of Geotechnical engineering School of Civil and Hydraulic EngineeringDalian University of Technology Department of civil engineering Huaihai Institute of Technology

By using the soil static and dynamic universal triaxial and torsional shear apparatus, a series of combined cyclic shear tests are performed to simulate the rotation in the principal stress direction induced by ocean wave. The tests include the cyclic preloading tests and liquefaction tests in the second loading on saturated loose sand with a relative density of 30%. The all tests are consolidated under isotropic condition. The effect of the cyclic preloading on the resistance to liquefaction of saturated loose sands under the condition of continuous rotation in the principal stress direction is investigated. Experimental data indicate that the void ratio of saturated sands has a negligible reduction after cyclic preloading. With the increase of the intensity of cyclic preloading (in the amplitude and in the number of cycles), the resistance to liquefaction in the second loading is increased continuously under the condition that the liquefaction does not occur during the cyclic preloading. The reason is that the construction of more stable structure due to the uniformity of the void and the better interlocking of the particles when the cyclic preloading is applied to the saturated sand.

关键词： saturated sand liquefaction continuous rotation in the principal stress direction cyclic preloading second loading void ratio

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 {2.,Changsha,Hunan 410083,china 2.Department of civil engineering,Hunan {2. of Technology,Zhuzhou,Hunan 412.08,china 3.school of Mechanical engineering,Purdue {2.,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

Research progress of the NSFC Major Research Plan “Dynamic Disaster Evolution of Major engineering Structures”

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Science china(Technological Sciences) 2010年第2期53卷 592-594页

作者： RU JiPing1, LI DaPeng1, LI ZhongXian2.1 Department of engineering & Materials Science, NSFC, Beijing 100085, china 2.{2. of civil engineering, Tianjin university, Tianjin 300072. china 1. Department of engineering & Materials Science NSFC Beijing 100085 China2. School of Civil Engineering Tianjin University Tianjin 300072 China

The NSFC Major Research Plan aims to conduct researches at the international research frontiers on modeling of strong earthquake ground motions and strong wind or typhoon fields, and investigating the damage and failure evolution process of the major engineering structures under dynamic actions, focusing on the following two key scientific problems: (1) characteristics and laws of strong earthquake ground motions and strong wind or typhoon fields, and (2. process and mechanism of dynamic disaster evolution of the major engineering structures. For these goals, the research work is targeted at (1) modeling and predicting of strong earthquake ground motion and strong wind or typhoon fields, (2. identifying critical parameters influencing the dynamic disaster evolution of the major engineering structures, (3) analyzing the whole dynamic disaster evolution process of the major engineering structures, and (4) integration and verification of simulation systems for dynamic disaster evolution of the major engineering structures.

关键词： major engineering structures dynamic disaster evolution research progress

The double reflection on the interface of uniaxial crystals in the Savart polariscope

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Science china(Physics,Mechanics & Astronomy) 2009年第7期52卷 1003-1006页

作者： WU JunFang1,2.& ZHANG ChunMin1 1 school of Science, Xi’an jiaotong {2., Xi’an 710049, china 2.school of Science, Xi’an Polytechnic {2., Xi’an 710048, china school of Science Xi’an Jiaotong University Xi’an 710049 China school of Science Xi’an Polytechnic University Xi’an 710048 China

The reflection in the Savart polariscope is different from the isotropic medium. The double reflection of rays in the Savart polariscope is analyzed and discussed on the basis of the Snell law. The double reflection formulae of the extraordinary ray and the ordinary ray are given. These results may provide a theoretical and practical guide for studying, developing and engineering polarization interference imaging spectrometers.

关键词： the Savart polariscope double reflection the Snell law extraordinary ray ordinary ray

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牵引变压器绕组变形在线检测方法研究

铁道学报 2004年第2期26卷 60-65页

作者：高仕斌王果西南交通大学电气工程学院四川成都610031

国内外的研究和统计表明,变压器绕组变形是电力系统安全运行的一大隐患,通过测量变压器绕组短路电抗来判断变压器绕组是否变形是一种有效的方法。本文提出了2.通过在线监测原、次边的电压和电流,实时计算绕组的短路电抗来判断变压器绕... 详细信息

国内外的研究和统计表明,变压器绕组变形是电力系统安全运行的一大隐患,通过测量变压器绕组短路电抗来判断变压器绕组是否变形是一种有效的方法。本文提出了2.通过在线监测原、次边的电压和电流,实时计算绕组的短路电抗来判断变压器绕组变形的方法,并对电气化铁路主要接线形式的牵引变压器绕组变形的在线监测方案进行了设计。论文分析了互感器误差对短路电抗测量结果的影响;通过变压器建模,分析了磁滞特性和负载变化大小对短路电抗测量结果的影响,验证了该方法在工程应用上的可行性。

关键词：变压器绕组变形短路电抗在线监测

Multi-symplectic method to analyze the mixed state of Ⅱ-superconductors

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Science china(Physics,Mechanics & Astronomy) 2008年第12期51卷 1835-1844页

作者： HU WeiPeng1↑ & DENG ZiChen1,2.1 school of Mechanics, civil {2. and architecture, Northwestern Polytechnical university, Xi’an 710072. china 2.State Key Laboratory of Structural Analysis of Industrial Equipment, Dalian university of Technology, Dalian 11602., china school of Mechanics Civil Engineering and Architecture Northwestern Polytechnical University Xi’an China State Key Laboratory of Structural Analysis of Industrial Equipment Dalian University of Technology Dalian China

The mixed state of two-band II-superconductor is analyzed by the multi-symplectic method. As to the Ginzburg-Landau equation depending on time that describes the mixed state of two-band II-superconductor, the multi-symplectic formulations with several conservation laws: a multi-symplectic conservation law, an energy con- servation law, as well as a momentum conservation law, are presented firstly; then an eighteen points scheme is constructed to simulate the multi-symplectic partial differential equations (PDEs) that are derived from the Ginzburg-Landau equation; finally, based on the simulation results, the volt-ampere characteristic curves are obtained, as well as the relationships between the temperature and resistivity of a suppositional two-band II-superconductor model under different magnetic intensi- ties. From the results of the numerical experiments, it is concluded that the notable property of the mixed state of the two-band II-superconductor is that: The trans- formation temperature decreases and the resistivity ρ increases rapidly with the increase of the magnetic intensity B. In addition, the simulation results show that the multi-symplectic method has two remarkable advantages: high accuracy and excellent long-time numerical behavior.

关键词： two-band Ginzburg-Landau equation mixed state multi-symplectic conservation law