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Journal of Wuhan University of Technology(Materials Science) 2018年第6期33卷 1465-1471页

作者： ZHANG Hao she wei School of Material Science and Engineering Southeast UniversityNanjing 211189China State Key Laboratory of High Performance Civil Engineering Material Nanjing 211100China

A numerical model was proposed to describe the modulus variation of mortar exposed to external sulfate attack and the effectivity was verified by experiments. The model joints statistical evolution of microcracks to effective elastic modulus with microcracks and is applied to predict the damage degree of mortar attacked by sulfate. The experimental results show that the model can predict the modulus variation development of the specimen and the microcraks density. The elastic modulus values calculated by the model are consistent with that measured by experiments. The model focuses on nucleation of microcracks and finds that the theoretical results of microcracks number density show a linear growth over time in mortar. Compared with other sulfate attack damage model, this model provides a more suitable damage evolution equation that can be used to analyze the chemically assisted damage.

关键词： sulfate attack effective elastic modulus microcracks number density damage evolution

Forging-microstructure-tensile properties correlation in a new nearβhigh-strength titanium alloy

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Rare Metals 2021年第8期40卷 2109-2117页

作者： Huan Wang she-wei Xin Yong-Qing Zhao wei Zhou wei-Dong Zeng State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China Titanium Alloy Research Institute Northwest Institute for Nonferrous Metal ResearchXi’an710016China

Microstructures and tensile properties of a newβhigh-strength titanium alloy Ti-5321(Ti-5 Al-3 Mo-3 V-2 Zr-2 Cr-1 Nb-1 Fe)were investigated in this *** microstructures,including equiaxed microstructure(EM),bimodal microstructure(BM),basket-weave microstructure(WM)and lamellar microstructure(LM),were tailored by changing the forging process,and the influences of different microstructures on tensile properties were also *** results indicated that Ti-5321 exhibits a better combination of strength and ductility,compared to Ti-5553,Ti-1023,BT22 and *** ultimate tensile strength,total elongation and reduction in area could be achieved in a range of 1200-1300 MPa,10%-15%and40%-60%,*** influences of variant selection on the tensile properties in Ti-5321 alloy were also ***βforging and solution treatment,αphase maintained strictly Burgers orientation relation with adjacentβ*** features of the fractography in BM and LM were also explored to further explain the tensile properties and the fracture mode of Ti-5321 alloy.

关键词： New nearβtitanium alloy Forging process Variant selection Tensile properties

Effect of Functional Chemical Admixtures on the Performance of Cement Asphalt Mortar Used in Ballastless Track

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Journal of Wuhan University of Technology(Materials Science) 2015年第5期30卷 995-1000页

作者：蒋金洋 she wei LI wei PAN Li Jiangsu Key Laboratory for Construction Materials Southeast University Jiangsu Institute of Building Science Co.LTD

Chemical admixtures are of paramount importance to the performance of modern cement based composites. In this paper, we performed a series of tests to investigate the effects of chemical admixtures on the cement asphalt mortar(CA mortar), i e, compressive strength, frost resistance, permeability, fatigue resistance, pore structure and microstructure. In particular, two types of chemical admixtures were tested, i e, defoamer(tributyl phosphate(TBP)) and polycarboxylate superplasticizer(PS). The results indicate that the addition of TBP and PS eliminates big bubbles and promotes small non-connected pores forming in matrix. Besides, an optimum dosage of TBP and PS may be determined with respect to the frost resistance, permeability and fatigue resistance of CA mortar. Further elaborative discussions are presented as well as experimental evidences from mercury intrusion porosimetry, scanning electron microscopy and energy dispersive spectroscopy.

关键词： cement asphalt mortar chemical admixture frost resistance fatigue resistance pore structure microstructure

Magnesium bistrifluoromethanesulfonimide as an efficient catalyst for the hydroalkylation of aromatic olefins with 1,3-diketones under solvent-free conditions

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Chinese Chemical Letters 2011年第8期22卷 911-914页

作者： Hong she Wang wei Xing Zhao Shaanxi Key Laboratory for Phytochemistry Baoji University of Arts and Sciences Baoji 721013 China

An efficient magnesium bistrifluoromethanesulfonimide[Mg（NTf_2）_2]catalyzed hydroalkylation of aromatic olefins with 1,3- diketones under solvent-free conditions has been *** reactions proceed smoothly to give the d... 详细信息

关键词： Hydroalkylation Aromatic oletins 1 3-Diketones Magnesium bistrifluoromethanesulfonimide

In-situ Monitoring the Setting Behavior of Foamed Concrete Using Ultrasonic Pulse Velocity Method

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Journal of Wuhan University of Technology(Materials Science) 2013年第6期28卷 1146-1154页

作者： she wei ZHANG Yunsheng JONES MR GUO Panpan Jiangsu Key laboratory for Construction Materials Southeast University Concrete Technology Unit Division of Civil EngineeringUniversity of Dundee

The applicability of ultrasonic pulse velocity （UPV） method to in-situ monitor setting and hardening process of foamed concrete （FC） was systematically investigated. The UPVs of various FC pastes were automatically and continuously measured by a specially designed ultrasonic monitoring apparatus （UMA）. Ultrasonic tests were performed on FC mixtures with different density （300, 500, 800 and 1 000 kg/m3）, and different fly ash contents （0%, 20%, 40% and 60%）. The influence of curing temperatures （20, 40, 60 and 80~C） was also studied. The experimental results show that three characteristic stages can be clearly identified during the setting process of an arbitrary FC paste： dormant stage, acceleration stage, and deceleration stage. Wet density, fly ash content, and curing temperature have great impact on setting behavior. A stepwise increase of the wet density results in shorter dormant stage and larger final UPV. Hydration reaction rate is obviously promoted with an increase in curing temperature. However, the addition fly ash retards the microstn,lcture formation. To aid in comparing with the ultrasonic results, the consistence spread test and Vicat needle test （VNT） were also conducted. A correlation between ultrasonic and VNT results was also established to evaluate the initial and final setting time of the FC mixtures. Finally, certain ranges of UPV with reasonable widths were suggested for the initial and final setting time, respectively.

关键词： foamed concrete (FC) early age setting behavior ultrasonic monitoring setting time consistence

Characterization of Surface Hardness and Microstructure of High Performance Concrete

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Journal of Wuhan University of Technology(Materials Science) 2018年第1期33卷 124-132页

作者：杨永敢张云升 she wei School of Materials Science and Engineering Southeast University

The relationship between compressive strength obtained by universal testing machine and rebound value obtained by the hammer of high performance concrete was systematically investigated at the macro level. And a model of high performance concrete strength curve was established from them. At the micro level, the microstructure, hydration products and pore structure of concrete surface were analyzed by scanning electron microscopy（SEM）, comprehensive thermal analysis（TG-DSC） and mercury intrusion porosimetry（MIP）, respectively. The effect of carbonation on surface strength was also investigated. The results showed that the concrete surface hardness layer grew rapidly at early stage and then stabilized at last with ongoing curing age; the rebound value and compressive strength of concrete with slag were higher than those of concrete with the same content of fly ash. In addition, the strength curve obtained by the least square method can satisfy the local standard requirements with an average relative error of 8.9% and a relative standard deviation of 11.3%. When the carbonation depth was 6 mm, the compressive strength calculated by national uniform strength curve was 25 PMa higher than that by high performance concrete.

关键词： high performance concrete rebound test parameter analysis strength curve

Fast UAV path planning in urban environments based on three-step experience buffer sampling DDPG

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Digital Communications and Networks 2024年第4期10卷 813-826页

作者： Shasha Tian Yuanxiang Li Xiao Zhang Lu Zheng Linhui Cheng wei she wei Xie College of Computer Science South-Central Minzu UniversityWuhan430074China Hubei Provincial Engineering Research Center for Intelligent Management of Manufacturing Enterprises Wuhan430074China School of Computer Science Wuhan UniversityWuhan430072China School of Mathematics&Statistics South-Central Minzu UniversityWuhan430074China

The path planning of Unmanned Aerial Vehicle(UAV)is a critical issue in emergency communication and rescue operations,especially in adversarial urban *** to the continuity of the flying space,complex building obstacles,and the aircraft's high dynamics,traditional algorithms cannot find the optimal collision-free flying path between the UAV station and the ***,in this paper,we study the fast UAV path planning problem in a 3D urban environment from a source point to a target point and propose a Three-Step Experience Buffer Deep Deterministic Policy Gradient(TSEB-DDPG)*** first build the 3D model of a complex urban environment with buildings and project the 3D building surface into many 2D geometric *** transformation,we propose the Hierarchical Learning Particle Swarm Optimization(HL-PSO)to obtain the empirical ***,to ensure the accuracy of the obtained paths,the empirical path,the collision information and fast transition information are stored in the three experience buffers of the TSEB-DDPG algorithm as dynamic guidance *** sampling ratio of each buffer is dynamically adapted to the training ***,we designed a reward mechanism to improve the convergence speed of the DDPG algorithm for UAV path *** proposed TSEB-DDPG algorithm has also been compared to three widely used competitors experimentally,and the results show that the TSEB-DDPG algorithm can archive the fastest convergence speed and the highest *** also conduct experiments in real scenarios and compare the real path planning obtained by the HL-PSO algorithm,DDPG algorithm,and TSEB-DDPG *** results show that the TSEBDDPG algorithm can archive almost the best in terms of accuracy,the average time of actual path planning,and the success rate.

关键词： Unmanned aerial vehicle Path planning Deep deterministic policy gradient Three-step experience buffer Particle swarm optimization

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Chinese Physics Letters 2014年第3期31卷 14-17页

作者： ZHAO Hu LI Tie-Fu LIU Jian-she CHEN wei Institute of Microelectronics Tsinghua National Laboratory of Information Science and Technology Tsinghua University Beijing 100084

A phase-slip flux qubit, exactly dual to a charge qubit, is composed of a superconducting loop interrupted by a phase-slip junction. We propose a tunable phase-slip flux qubit by replacing the phase-slip junction with a charge-related superconducting quantum interference device （SQUID） consisting of two phase-slip junctions connected in series with a superconducting island. This charge-SQUID acts as an effective phase-slip junction controlled by the applied gate voltage and can be used to tune the energy-level splitting of the qubit. In addition, we show that a large inductance inserted in the loop can reduce the inductance energy and consequently suppress the dominating flux noise of the phase-slip flux qubit. This enhanced phase-slip flux qubit is exactly dual to a transmon qubit.

关键词： SQUIDs

Simulation of the Cracking and Ablation Behavior of Ferrosiliceous and Siliceous Nuclear Sacrificial Concretes

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Journal of Wuhan University of Technology(Materials Science) 2016年第5期31卷 982-988页

作者：蒋金洋 YU Yingjun CHU Hongyan SUN wei GAO Yun she wei School of Materials Science and Engineering Southeast UniversityNanjing 211189China Jiangsu Key Laboratory of Construction Materials Southeast UniversityNanjing 211189China

We investigated the simulation of the cracking and ablation behavior of ferro-siliceous and siliceous nuclear sacrificial concretes. To this end, four type of sacrificial concretes were fabricated, i e, the ferro-siliceous（F） and siliceous（S） plain concretes, and the polypropylene fiber reinforced concretes of the above two（FF, SF）. The cracking and ablation behaviors of the sacrificial concretes were investigated by simulation tests, and the simulated elevated temperature was obtained by means of thermite powder. The number and the width of the cracks were compared and the pore size distribution of sacrificial concretes was measured. In addition, the interface and chemical composition of melt at different positions were analyzed, and the ablation depth of the sacrificial concrete crucibles was also measured. It was found that the siliceous concrete shows to be more prone to cracking than the ferro-siliceous concrete due to the higher content of fly ash and lower water to binder ratio; though the ablation depth of siliceous concrete is found to be slightly larger, no clear difference can be detected for the basemat ablation rate.

关键词： sacrificial concrete cracking ablation MCCI high temperature

Mutual Quenching of Self-pumped Phase Conjugation by Incoherent ps Laser Pulses

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Chinese Physics Letters 1996年第11期13卷 844-847页

作者： she wei-long CHEN Ying-yu YU Zhen-xin LEE Wingkee State Key Laboratory of Ultrafast Laser Spectroscopy Zhongshan UniversityGuangzhou 510275 Department of Physics The Chinese University of Hong KongShatin NTHong Kong

When two beams of incoherent cw mode-locked ps laser pulses were incident upon opposite faces perpendicular to the a-axis of a Cu-doped KNSBN crystal,no mutually pumped phase conjugation as that generated by continuous waves was observed,however,the stronger laser beam generated its self-pumped phase conjugation which was weakened by the weaker *** the intensities of the two beams were equal,self-pumped phase conjugation was completely quenched.

关键词： pumped coherent mutually