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Determination of the Thermal Expansion Coefficient of Concrete at Early Ages by Using Temperature-stress Testing Machine

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Journal of wuhan University of technology(Materials Science) 2006年第4期21卷 146-149页

作者：霍凯成 Hubei Key Laboratory of Roadway Bridge & Structure engineering Wuhan University of TechnologyWuhan 430070China

By using the uptodate temperatuer-stress testing machine, the thermal expansion coefficient of concrete at early ages was studied and indicative conclusions were achieved ： temperature rising due to hydration heat is not directly correlated with cracking, but the temperature and stress evolation process should be taken into consideration in the same time. Proper chemical admixtures and mineral cornpasitions can improve the mechanical properties of concrete such as thermal expansion coefficient, which is very indicative in practice.

关键词： concrete coefficient of thermal expansion temperature-stress test

Allocation of power generating and shipping of Hanjiang upstream cascade

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Progress in Natural Science:Materials International 2005年第8期15卷 733-741页

作者： LIU Junping1* and CHANG Mingqi 2.3.1. School of Civil engineering and Architecture, Zhejiang University of technology, Hangzhou 3.0014,{2. 2. {3. of Water Resources & Hydroelectric engineering, Xi'an University of technology, Xi'an 710048,{2. 3. Shanxi {3. of Water Resources, Taiyuan 03.001,{2.) School of Civil engineering and Architecture Zhejiang University of Technology Hangzhou 310014 China institute of Water Resources and Hydroelectric engineering Xi'an University of Technology Xi'an 710048 China Shanxi institute of Water Resources Taiyuan 030001 China

The optimal model and simulating model of the Hanjiang cascade reservoirs operation with one day as its calculating period are established to coordinate the contradictions between power generating and shipping. The optimal model is solved by progressive optimality algorithm method adopting the theory of large system decomposing and coordinating. By analyzing the water allocation results obtained from six schemes, which are two cascades, four cascades and seven cascades joint operation considering shipping or not, the contradiction degree between power generating and shipping is investigated and some joint operation schemes are proposed.

关键词： cascade power generating contradiction shipping optimal operation.

Spectral anomalies and spectral switches of partially coherent and polychromatic light diffracted at an aperture

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Science china(Physics,Mechanics & Astronomy) 2004年第1期47卷 24-35页

作者： Lü Baida1, 3.& PAN Liuzhan1, 2.1. institute of laser Physics and Chemistry, Sichuan University, Chengdu 610064,{2. 2. Department of Physics, Luoyang Normal College, Luoyang 47102.,{2. 3. State Key Laboratory of laser technology, Huazhong University of Science and technology, wuhan 43.074,{2. Correspondence should be addressed to L Baida (email: badalu@***) Received July 10, 2.03 institute of laser Physics and Chemistry Sichuan University Chengdu China State Key Laboratory of laser technology Huazhong University of Science and Technology Wuhan China Department of Physics Luoyang Normal College Luoyang China

Based on the propagation theory of partially coherent light in the space-frequency domain, the anomalous spectral behavior and spectral switches in the far field of partially coherent and polychromatic light diffracted at an aperture are studied. It is shown that, as compared with spatially fully coherent and polychromatic light whose spectral anomalies are induced only by aperture diffraction, the spectral anomalies and spectral switches of partially coherent and polychromatic light depend on the aperture diffraction, spatial correlationβ and bandwidth of the original spectrum. Detailed numerical calculations are made to illustrate the behavior of spectral switches of partially coherent and polychromatic light, and the results for spatially fully coherent and polychromatic light are treated as a special case ofβ=1 and included in our theory.

关键词： spectral anomaly spectral switch partially coherent and polychromatic light far field aperture diffraction

A low frequency piezoelectric power harvester using a spiral-shaped bimorph

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Science china(Physics,Mechanics & Astronomy) 2006年第6期49卷 649-659页

作者： HU Yuantai1,2.HU Hongping2.& YANG Jiashi3.1. institute of Mechanics and Sensing {3.,Central South University,Changsha 410083.{2. 2. Department of Mechanics,Huazhong University of Science and {3.,wuhan 43.074,{2. 3. Department of engineering Mechanics,University of Nebraska,Lincoln,NE 68588-052.,USA institute of Mechanics and Sensing technology Central South University Changsha China Department of Mechanics Huazhong University of Science and Technology Wuhan China Department of engineering Mechanics University of Nebraska Lincoln USA

We propose a spiral-shaped piezoelectric bimorph power harvester operating with coupled flexural and extensional vibration modes for applications to low frequency energy sources. A theoretical analysis is performed and the computational results show that the spiral structure has relatively low operating frequency compared to beam power harvesters of the same size. It is found that to optimize the performance of a piezoelectric spiral-shaped harvester careful design is needed.

关键词： spiral-shaped bimorph,piezoelectric harvester,power density.

Early Hydration of Composite Cement with Thermal Activated Coal Gangue

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Journal of wuhan University of technology(Materials Science) 2010年第1期25卷 162-166页

作者：郭伟 Department of Material engineering Yancheng Institute of Technology institute of Material Science and engineering Nanjing University of Technology

Composite cement samples were prepared by mixing clinker, gypsum with burnt coal gangues which was calcined at various temperatures. The mechanical strength and Ca（OH）2.content in the cement paste were tested, and the paste composition and microstructure were analyzed by thermogravimetry-differential thermal analysis （TG-DSC）, X-ray diffraction（XRD）, scanning electronic microscopy （SEM） and pore structure analysis. Results demonstrate that the thermal activated coal gangue could accelerate the early hydration of cement clinker obviously, which promotes the gangue hydration itself. The early hydrated products of the cement are C-S-H gel, Ca（OH）2.and AFt. The cement with 3.% （in mass） the gangue exhibits higher mechanical strength, and among all the cement samples the one with the gangue burnt at 700 ℃ displays the highest hydration rate, mechanical strength, the most gel pores and the lowest total porosity.

关键词： blended cement hydration microstructure hydration product

Surface Nanocrystallization of Magnesium Alloy AZ91D by High-Energy Shot Peening

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Journal of wuhan University of technology(Materials Science) 2009年第4期24卷 515-519页

作者：张津 School of Materials Science & engineering University of Science and Technology Beijing College of Materials Science & engineering Chongqing University of Technology

High-energy shot peening （HESP）, a method to produce severe plastic deformation by high velocity flying balls, was applied on die cast magnesium alloy AZ91D. Effects of surface nanocrystallization by HESP and heat treatment at different temperatures were investigated. The mi- crostructure evolution was conducted using X-ray diffraction （XRD） and field emission scanning electronic microscopy （FESEM）. The hardness was measured by microhardness tester. The experimental results show that surface nanocrystrallization of AZ91D obtained by HESP would lead to the increase of microhardness. Low temperature heated at 100℃ for 1 h do not change the property obviously. However, both the microstructure and microhardness vary greatly after heat treatment at 400℃ for 1 h.

关键词： AZ91 D surface nanocrystallization HESP microhardnss corrosion resistance

Growth of Carbon Encapsulated Long Nickel Nanorods on Bulk Nickel Substrate

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Journal of wuhan University of technology(Materials Science) 2011年第1期26卷 28-32页

作者：宾晓蓓 College of Resources & Environment engineering Wuhan University of Technology

Carbon nanotube encapsulated nickel nanorods were catalytic grown via pyrolysis of oil on a bulk nickel wire substrate. X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy were employed to characterize the as-prepared sample. The results show that, carbon nanotubes possess several microns in length, the filled metallic nickel nanorods with a uniform diameter of 3. nm were tightly encapsulated by the carbon capsules. The detailed formation mechanism for the carbon nanotubes encapsulated nickel nanorods were discussed briefly.

关键词： carbon nanotube nickel nanorod pyrolysis core-shell

Second-order consensus in networks of dynamic agents with communication time-delays

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Journal of Systems engineering and Electronics 2010年第1期21卷 88-94页

作者： Bo Yang1,2. Huajing Fang3. and Hua Wang4 1. School of Navigation, wuhan University of technology, wuhan 43.063. P. R.{3. 2. wuhan Second Ship Design and Research institute, wuhan 43.064, P. R.{3. 3. Department of Control Science and engineering, Huazhong University of Science and technology, wuhan 43.074, P. R.{3. 4. Department of Aerospace and Mechanical engineering, Boston University, Boston MA02.15, USA School of Navigation Wuhan University of Technology Wuhan 430063 P. R. China wuhan Second Ship Design and Research institute Wuhan 430064 P. R. China Department of Control Science and engineering Huazhong University of Science and Technology Wuhan 430074 P. R. China Department of Aerospace and Mechanical engineering Boston University Boston MA02215 USA

This paper proposes second-order consensus protocols with time-delays and gives the measure of the robustness of the protocols to the time-delay existing in the network of agents with second-order dynamics. By employing a frequency domain method, it is proven that the information states and their time derivatives of all the agents in the network achieve consensus asymptotically, respectively, for appropriate communication timedelay if the topology of weighted network is connected. Particularly, a tight upper bound on the communication time-delay that can be tolerated in the dynamic network is found. The consensus protocols are distributed in the sense that each agent only needs information from its neighboring agents, which reduces the complexity of connections between neighboring agents significantly. Numerical simulation results are provided to demonstrate the effectiveness and the sharpness of the theoretical results for second-order consensus in networks in the presence of communication time-delays.

关键词： second-order consensus protocols dynamic networks algebraic graph theory frequency domain analysis com-munication constraints.

Algorithm of graph isomorphism with threedimensional DNA graph structures

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Progress in Natural Science:Materials International 2005年第2期15卷 86-89页

作者： LIU Guangwu 1,2., YIN Zhixiang 1,3. XU Jin1 and DONG Yafei1(1. Department of Control Science and engineering, Hua Zhong University of Science and technology,{2.,{3. 2. College of Transportation, wuhan University of technology, wuhan 43.063.{3. 3. Department of Mathematics and Physics, Anhui University of Science and technology, Huainan 2.2.01,{3.) Dept. of Control Science and Eng. Huazhong Univ. of Sci. and Technol. Wuhan 430074 China Coll. of Transportation Wuhan Univ. of Technology Wuhan 430063 China Dept. of Mathematics and Physics Anhui Univ. of Sci. and Technol. Huainan 232001 China

An algorithm for solving the graph isomorphism problem with 3.D DNA structures is proposed in this paper. The k-armed branched junction molecules are used to code k-degree vertices. Double stranded molecules are used to code edges. Then the molecules are mixed in a tube to be ligated. The result can be detected by gel electrophoresis. The time complexity of the algorithm is O(n2., where n is the number of vertices of the graph.

关键词： DNA computing DNA graph structure graph isomorphism