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Early Age Hydration of Cement Paste Monitored with Ultrasonic Velocity and Numerical Simulation

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Journal of wuhan university of {2.(Materials science) 2010年第4期25卷 704-707页

作者：陈伟 Key Laboratory of Silicate Materials science and Engineering Ministry of EducationWuhan University of Technology school of Materials science and Engineering Wuhan University of Technology

Early age hydration of cement paste was investigated by monitoring the ultrasonic propagation velocity and simulated with the numerical model CEMHYD3D. The ultrasonic velocity of the P-wave was recorded during the first 2. hours of the hydration process and its evolution was analyzed. It is shown that the UPV method is an effective, accurate and non-destructive method for monitoring the early age hydration process of cement paste. The early age hydration process can be classified as four periods, which are the dormant period, acceleration period, deceleration period and stabilization period. Higher w/c ratios result in lower UPV, and delay initial setting time due to the decreased solid volume. The change of UPV is clearly related to the hydration degree of cement particles.

关键词： early age hydration ultrasonic velocity hydration degree CEMHYD3D

Design and Develop Online Monitoring and Early-warning System of Crane Structural Stress

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武汉理工大学学报 2006年第S2期28卷 724-727页

作者： XU Huping~1 LIN Weiguo~2.XU Changsheng~2.1.school of automation,{2. university of technology,{2. 430070,china 2.school of Material Engineering,{2. university of Tedmology,{2. 430070 ,china school of automation Wuhan University of TechnologyWuhan 430070China school of Material Engineering Wuhan University of TechnologyWuhan 430070China

This paper proposed an online monitoring and early-warning system of dynamic stress of crane metal structure, and designed this system’s hardware,including sensor unit,data gathering unit,and controlling & processing unit of this sys- tem,and discussed the waterproof protection for resistance strain wafer and scheme of data gathering and transmission of dynamic strain gauge,moreover developed system software of real-time and online monitoring dynamic stress,including data gathering by DLL and data display & processing based on Visual C++.The system applies the dynamic strain gauge to gather the data of the stress,and communicates between PLC control system of crane and upper industrial computer,so that realize the real-time online monitoring and early-warning for crane’s metal structure *** test results show this system carry on real time and online monitoring to dynamic stress of loud-bearing metal structure longly and stability,and can give an alarm and overload protection on *** the system has good practice value.

关键词： crane metal structure stress detect online monitor

Early Age Compressive Strength of Pastes by Electrical Resistivity Method and Maturity Method

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Journal of wuhan university of {2.(Materials science) 2011年第5期26卷 983-989页

作者：肖莲珍 school of Materials science and Engineering Wuhan Institute of Technology

The compressive strength development of Portland cement pastes was investigated by the electrical resistivity method and the maturity *** experiments were carried out on the cement pastes with different water-cement ratios at different curing *** results show that the application of the maturity method has limitation to obtain the *** is found that both of the compressive strength and the electrical resistivity follow hyperbolic trend for all the *** hyperbolic equation of each mix is obtained to estimate the ultimate resistivity value which can probably be *** relationship between electrical resistivity and compressive strength of the cement pastes is established based on the test results and interpreted by the empirical Archie equation and a strength-porosity *** relationship between the electrical resistivity after temperature correction and the compressive strength was linear and independent of curing temperature and water-cement ratio.

关键词： electrical resistivity cement hydration compressive strength maturity method

Carbonation Resistance of Sulphoaluminate Cement-based High Performance Concrete

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Journal of wuhan university of {2.(Materials science) 2009年第4期24卷 663-666页

作者：张德成 school of Materials science and Engineering Wuhan University of Technology school of Materials science and Engineering University of Jinan

The influences of water/cement ratio and admixtures on carbonation resistance of sulphoaluminate cement-based high performance concrete （HPC） were investigated. The experimental results show that with the decreasing water/cement ratio, the carbonation depth of sulphoaluminate cement-based HPC is decreased remarkably, and the carbonation resistance capability is also improved with the adding admixtures. The morphologies and structure characteristics of sulphoaluminate cement hydration products before and after carbonation were analyzed using SEM and XRD. The analysis results reveal that the main hydration product of sulphoaluminate cement, that is ettringite （AFt）, decomposes after carbonation.

关键词： sulphoaluminate cement carbonation high performance concrete (HPC) admixture ettringite

Toughening Modification of Unsaturated Polyester Resin Using HDI Trimer

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Journal of wuhan university of {2.(Materials science) 2009年第4期24卷 627-630页

作者：段华军 school of Materials science and Engineering Wuhan University of Technology

HDI trimer was firstly used to improve the mechanical properties of hydroxyl-terminated unsaturated polyester （UP）. Mechanical properties measurements performed on the cured materials demonstrate a distinct improvement in intensity and toughness in the presence of HDI trimer and shows the change trends of increase and then decrease. The morphological analysis of the fracture surfaces shows that the micro-phase separated structures appear in modified UPR systems and changed from dendritric, dimple and to cystiform structures with the increase of HDI trimer content. The presence of the cystiform structures made the modified UPR systems present the best properties.

关键词： HDI trimer unsaturated polyester toughness mechanical properties morphology

Preparation and Absorption/Desorption Performance of Gypsum-based Humidity Controlling Materials

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Journal of wuhan university of {2.(Materials science) 2011年第4期26卷 684-686页

作者：姜洪义 school of Materials science and Engineering Wuhan University of Technology

Absorption/desorption properties of some humidity controlling materials which contain gypsum as basic cement materials and activated Sepiolite powder as humidity controlling media were tested. The kinetics curve of moisture adsorption/desorption were drawn and humidity controlling performance in nature environment was verified. The experimental results show that moisture absorption/desorption rates are increased, and the speed is also accelerated. These materials, which can adjust environmental humidity effectively, are new ones with good humidity controlling performance.

关键词： activated Sepiolite gypsum-composites humidity controlling performance

Dimensions of modified Besicovitch-Eggleston sets

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science china Mathematics 2006年第2期49卷 245-254页

作者： XIE Yuqiong & WEN Zhixiong Department of Mathematics, wuhan university of {2., wuhan 430070, china school of Mathematics and Statistics, wuhan university, wuhan 430072. china Department of Mathematics Wuhan University of Technology Wuhan 430070 China school of Mathematics Statistics Wuhan University Wuhan 430072 China

We consider the variants of Besicovitch-Eggleston sets in symbolic spaces, and determine their fractal dimensions.

关键词： Besicovitch-Eggleston set fractal dimension symbolic space multifractal.

Cure Reaction Kinetics of Low Pressure Sheet Molding Compound System Thickened by Crystalline Polymer

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Journal of wuhan university of {2.(Materials science) 2007年第2期22卷 380-384页

作者：秦岩 school of Materials science and Engineering Wuhan University of Technology

Several kinetic models for unsaturated polyester cure reaction and some existing parameter estimation techniques of these models were introduced. Correlated kinetic parameters and kinetic equations of the autocatalytic empirical kinetic model of LPSMC system were determined by using isothermal DSC to scan the system which was thickened by crystalline polymer （PEG-MAH）. Through using a serial curing degree of the system to validate the model, the experimental results were basically identical with the predictions of the autocatalytic empirical kinetic model. This model could provide a theoretical reference to the determination of molding techniques of low pressure SMC.

关键词： low pressure SMC curing kinetics model crystalline polymer

Electronic Structure of Doped Trans-Polyacetylene

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wuhan university Journal of Natural {2.s 2002年第1期7卷 51-53页

作者： Ren Da-zhi 1,2. Zhuang Wei 2. Wang Jun 2.1. wuhan university Journals Press,wuhan 430072.Hubei,china 2. school of Physics and technology, wuhan university, wuhan 430072.Hubei,china wuhan university Journals Press Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) wuhan university School of Physics and Technology Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) wuhan university School of Physics and Technology Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

The behavior of electronic structures of doped trans-polyacetylene is revealed by a simple method. (C2.H2.)+n is used to simulate p-type doped trans-polyacetylene at various doping concentrations. The electronic structure is calculated, by CNDO/2.method. These calculations show that at low doping level, the decrease of electronic energy compensates the increase of elastic energy, thus the bond alternation exists, and the charge carriers are solitons. When doping level is high, the increase of elastic energy is larger than the decrease, of electronic energy, the bond alternation disappears, solitons no longer exist, and polyacetylene is in a metalic state.

关键词： trans polyacetylene CNDO/2 electronic structure doped