作者： Jin, Jiao*;Xiao, Ting;Tan, Yanqing;Zheng, Jianlong;Liu, Ruohua*;...

期刊： Journal of Cleaner Production,2018年205:339-349 ISSN：0959-6526

通讯作者： Jin, Jiao;Liu, Ruohua

作者机构： [Xiao, Ting; Qian, Guoping; Wei, Hui; Zhang, Junhui; Jin, Jiao; Zheng, Jianlong; Tan, Yanqing] Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Changsha 410114, Hunan, Peoples R China.;[Liu, Ruohua] Cent S Univ, Sch Minerals Proc & Bioengn, Changsha 410083, Hunan, Peoples R China.

通讯机构： [Jin, Jiao; Liu, Ruohua] C;Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Changsha 410114, Hunan, Peoples R China.;Cent S Univ, Sch Minerals Proc & Bioengn, Changsha 410083, Hunan, Peoples R China.

关键词： Asphalt;Catalysis;Exhaust;Montmorillonite;TiO 2

摘要： Titanium dioxide (TiO2) pillared montmorillonite nanocomposites (T/M) have been prepared from montmorillonite (MMT) with tetrabutyl titanate by sol-gel method, and characterized by X-ray diffraction, transmission electron microscopy together with energy dispersive X-ray. Anatase TiO2 could be intercalated into the layer structure of MMT and dispersed on the outer surface, as the basal spacing increases by 0.26 nm for T/M. The influences of different contents of T/M on the properties of matrix asphalt and catalytic capacity for automobile exhaust were also investigated. T/M modified asphalt samples showed a remarkable increase on the G*/sin delta and improved resistance of asphalt pavement to failure for improved high temperature rheological performances. And T/M could improve the resistance of asphalt to UV aging effectively. What' more, T/M modified asphalt samples showed superior degradation capabilities of NO, CO and HC for simulating the catalysis of actual automobile exhaust. (C) 2018 Elsevier Ltd. All rights reserved.

语种： 英文

作者： Zhang, Junhui*;Peng, Junhui;Li, Jue;Zheng, Jianlong

期刊： International Journal of Civil Engineering,2018年16(12):1655-1667 ISSN：1735-0522

通讯作者： Zhang, Junhui

作者机构： [Peng, Junhui; Zhang, Junhui; Li, Jue; Zheng, Jianlong] Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Wanjiali South Rd, Changsha 410114, Hunan, Peoples R China.

通讯机构： [Zhang, Junhui] C;Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Wanjiali South Rd, Changsha 410114, Hunan, Peoples R China.

关键词： Resilient modulus;Soil suction;Cohesive soils;Prediction mode;Triaxial test

摘要： The resilient modulus, M R , of subgrade soils had been used extensively as an important unbound material property in the pavement design and analysis. The stress state and the humidity of cohesive soils have significant impacts on the resilient modulus. To predict the resilient modulus of cohesive soils in South China, the material indicator tests, an improved repeated load triaxial test and the pressure plate test were carried out. Then the SWCC was described using the Fredlund and Xing’s model with a relatively high coefficient of determination. Subsequently, the variation of resilient modulus with the stress state and the humidity characterized by the matric suction for cohesive soils were evaluated. A correlation between the matric suction and resilient modulus of cohesive soils was built, which has high correlation coefficients. In the following, a new resilient modulus estimation model for cohesive soils in South China incorporating the stress state and matric suction was proposed, which has a simple form, less parameters and only requires a universal triaxial testing system. After that, the new model was verified using the data of different cohesive soils from existing literature. The results show that the developed model has a high prediction accuracy. © 2018, Iran University of Science and Technology.

语种： 英文

作者： Tong, Hui;Dong, Pengyuan;Zhang, Jiafeng;Zheng, Junchao;Yu, Wanjing*;...

期刊： Journal of Alloys and Compounds,2018年764:44-50 ISSN：0925-8388

通讯作者： Yu, Wanjing

作者机构： [Wei, Kai; Dong, Pengyuan; Yu, Wanjing; Zheng, Junchao; Tong, Hui; Zhang, Jiafeng; Zhang, Bao] Cent S Univ, Sch Met & Environm, Changsha 410083, Hunan, Peoples R China.;[Liu, Zhimin] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha 410114, Hunan, Peoples R China.;[Chu, Dewei] Univ New South Wales, Sch Mat Sci & Engn, Sydney, NSW 2052, Australia.

通讯机构： [Yu, Wanjing] C;Cent S Univ, Sch Met & Environm, Changsha 410083, Hunan, Peoples R China.

关键词： Cathode material;Wet chemical method;LiNi0.8Co0.1Mn0.1O2;LaPO4 coating

摘要： In order to enhance the electrochemical properties of nickel-rich LiNi0.8Co0.1Mn0.1O2 cathode material, lithium-ion conductor shell was coated on the surface of the material through a facile wet chemical route. The morphologies, structures and chemical compositions of the samples were characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction, energy dispersive spectrometer and X-ray photoelectron spectroscopy. The result shows that the particle surface was uniformly coated by a very thin LaPO4 layer. Electrochemical measurements proved that the LaPO4 coated sample exhibited excellent cycling performance. The capacity retention of LaPO4-coated sample was 91.2% at 1 C after 100 cycles, which was higher compared with that of the pristine sample (76.4%). Moreover, the rate performance of the coated sample was greatly enhanced especially at 2, 5 and 10 C rate. The LaPO4-coated sample showed smaller charge transfer resistance and higher diffusion coefficient of lithium ions compared with those of the pristine sample. (C) 2018 Elsevier B.V. All rights reserved.

语种： 英文

作者： Ma, Yafei;Wang, Guodong;Su, Xiaochao;Wang, Lei*;Zhang, Jianren

期刊： Construction and Building Materials,2018年191:994-1003 ISSN：0950-0618

通讯作者： Wang, Lei

作者机构： [Ma, Yafei; Wang, Guodong; Wang, Lei; Su, Xiaochao; Zhang, Jianren] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.

通讯机构： [Wang, Lei] C;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.

关键词： Bridge engineering;Corrosion;Fatigue;Reinforced concrete;Stiffness

摘要： Corrosion of reinforcing bars accelerates the fatigue damage accumulation and significantly reduces the fatigue life of aging reinforced concrete (RC) bridges. This paper experimentally investigates the effects of corrosion on the fatigue behavior of reinforced concrete beams. An accelerated corrosion test is conducted in the laboratory conditions to obtain various corroded beam specimens. The initial crack width and the crack distribution are discussed. Based on the fatigue loading test, the load-deflection, fatigue crack propagation of concrete, fatigue life and the failure modes of RC beams after different fatigue cycles are investigated. Following that, a developed flexural stiffness calculation model for the corroded beams after fatigue is proposed. This model includes the effects of fatigue, corrosion-induced cracking and fatigue modulus degradation of concrete and other influential factors. The proposed method is validated with the experimental observations from various corroded RC beams of the current paper and available in open literature. © 2018

语种： 英文

作者： Wang, Zhi;Zhang, Tongyao;Ding, Mei;Dong, Baojuan;Li, Yanxu;...

期刊： Nature Nanotechnology,2018年13(7):554-559 ISSN：1748-3387

通讯作者： Yang, Teng;Han, Zheng;Chen, Yuansen

作者机构： [Wang, Hanwen; Li, Da; Zhang, Zhidong; Wang, Zhi; Huang, Jianqi; Yang, Teng; Li, Yong; Chen, Maolin; Sun, Dongming; Dong, Baojuan; Han, Zheng; Zhang, Tongyao; Han, Z; Zhao, Xiaotian; Li, Xiaoxi] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang, Liaoning, Peoples R China.;[Wang, Hanwen; Li, Da; Zhang, Zhidong; Wang, Zhi; Huang, Jianqi; Yang, Teng; Li, Yong; Chen, Maolin; Sun, Dongming; Dong, Baojuan; Han, Zheng; Zhang, Tongyao; Han, Z; Zhao, Xiaotian; Li, Xiaoxi] Univ Sci & Technol China, Sch Mat Sci & Engn, Hefei, Anhui, Peoples R China.;[Zhang, Tongyao; Zhang, Jing; Chen, Yuansen; Li, Yanxu] Shanxi Univ, Inst Optoelect, State Key Lab Quantum Opt & Quantum Opt Devices, Taiyuan, Shanxi, Peoples R China.;[Zhang, Tongyao; Zhang, Jing; Chen, Yuansen; Li, Yanxu] Shanxi Univ, Collaborat Innovat Ctr Extreme Opt, Taiyuan, Shanxi, Peoples R China.;[Jia, Chuankun; Ding, Mei] Changsha Univ Sci Technol, Coll Mat Sci & Engn, Changsha, Hunan, Peoples R China.

通讯机构： [Yang, T; Han, Z] C;[Yang, T; Han, Z] U;[Chen, Yuansen] S;Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang, Liaoning, Peoples R China.;Univ Sci & Technol China, Sch Mat Sci & Engn, Hefei, Anhui, Peoples R China.

摘要： Manipulating a quantum state via electrostatic gating has been of great importance for many model systems in nanoelectronics. Until now, however, controlling the electron spins or, more specifically, the magnetism of a system by electric-field tuning has proven challenging 1-4 . Recently, atomically thin magnetic semiconductors have attracted significant attention due to their emerging new physical phenomena 5-13 . However, many issues are yet to be resolved to convincingly demonstrate gate-controllable magnetism in these two-dimensional materials. Here, we show that, via electrostatic gating, a strong field effect can be observed in devices based on few-layered ferromagnetic semiconducting Cr2Ge2Te6. At different gate doping, micro-area Kerr measurements in the studied devices demonstrate bipolar tunable magnetization loops below the Curie temperature, which is tentatively attributed to the moment rebalance in the spin-polarized band structure. Our findings of electric-field-controlled magnetism in van der Waals magnets show possibilities for potential applications in new-generation magnetic memory storage, sensors and spintronics. © 2018 The Author(s).

语种： 英文

作者： He, Kan;Gao, Guang-jun;Wang, Jia-bin;Fu, Min;Miao, Xiu-juan*;...

期刊： Tunnelling and Underground Space Technology,2018年82(Dec.):416-427 ISSN：0886-7798

通讯作者： Zhang, Jie;Miao, Xiu-juan

作者机构： [He, Kan; Wang, Jia-bin; Fu, Min; Gao, Guang-jun; Zhang, Jie] Cent S Univ, Sch Traff & Transportat Engn, Minist Educ, Key Lab Traff Safety Track, Changsha, Hunan, Peoples R China.;[Miao, Xiu-juan] Changsha Univ Sci & Technol, Coll Automot & Mech Engn, Changsha, Hunan, Peoples R China.

通讯机构： [Zhang, Jie; Miao, Xiu-juan] C;Cent S Univ, Sch Traff & Transportat Engn, Minist Educ, Key Lab Traff Safety Track, Changsha, Hunan, Peoples R China.;Changsha Univ Sci & Technol, Coll Automot & Mech Engn, Changsha, Hunan, Peoples R China.

关键词： CFD;IDDES;Turbine;High-speed train;Tunnel

摘要： A simulation of the turbine driven by a high-speed train-induced wind in the tunnel was performed using the IDDES method with the SST k-w turbulence model. A full-scale real train experiment was conducted, and the results from a previously published study were employed to verify the computational method and mesh used for the simulation of the flow fields around the train and the turbine. The results show that the differences between the experiment and simulation results are very small. Next, certain variations of the torque of the turbine, the vorticity, velocity, pressure and specific dissipation rate of the flow field around the turbine during the process of the train crossing a tunnel are analysed. The obtained results show that not only the wake of the tail car but also the flow around the head car exerts great influence on the turbine. Next, a series of comparative studies were performed. The relationship between the maximum torque of the turbine and the distances from the turbine to the entrance and the exit of the tunnel, which can be modelled as power functions, were proposed. It was observed that while the maximum torque of the turbine decreases when the length of a tunnel varies from 100 to 300 m, it increases with the increasing length of the tunnel for lengths between 300 and 800 m.

语种： 英文

作者： Hou, Shuguang;Chen, Chen*;Zhang, Junhui;Shen, Huajie;Gu, Fan

期刊： Construction and Building Materials,2018年191:1221-1229 ISSN：0950-0618

通讯作者： Chen, Chen

作者机构： [Hou, Shuguang; Shen, Huajie] Nanjing Tech Univ, Coll Transportat Sci & Engn, Nanjing 210009, Jiangsu, Peoples R China.;[Chen, Chen; Gu, Fan] Auburn Univ, Natl Ctr Asphalt Technol, 277 Technol Pkwy, Auburn, AL 36830 USA.;[Zhang, Junhui] Changsha Univ Sci & Technol, Lab Highway Maintenance Technol, Natl Engn, Changsha 410004, Hunan, Peoples R China.

通讯机构： [Chen, Chen] A;Auburn Univ, Natl Ctr Asphalt Technol, 277 Technol Pkwy, Auburn, AL 36830 USA.

关键词： Asphalt emulsions;Microsurfacing;Thermal stability;WTAT

摘要： In this study, four different emulsifiers were used to prepare asphalt emulsions. The effects of emulsifiers on emulsion stability were investigated using the storage stability test, laser particle size analyzer (LPSA), and differential scanning calorimetry (DSC). Furthermore, aggregate (0.15–0.3 mm) was mixed with asphalt emulsions to obtain emulsified asphalt mortar. The Brookfield rotational viscometer (BRV) was employed to determine the mortar viscosity and equilibration time. According to the laboratory results, the storage stability of asphalt emulsions were in agreement with the corresponding particle size and specific surface area. There was a linear relationship between the square of particle size and storage stability. In addition, the QA-emulsifier-prepared asphalt emulsion yielded the smallest particle size and greatest specific surface area. This indicated the QA asphalt emulsion had the highest storage stability, which was followed by AA, XA, and IM asphalt emulsion, respectively. The DSC results showed that the enthalpy change displayed a linear relationship with the equilibration time. It was also demonstrated that the XA asphalt emulsion had the highest thermal stability, which was followed by AA, IM, and QA asphalt emulsion, respectively. This implied that there was no consistent ranking between storage stability and thermal stability. Finally, the AA asphalt emulsion was selected to prepare microsurfacing mixtures. The performance tests results indicated that aggregate gradation, aggregate temperature, additional water content, cement content and sand equivalent affected the mixing time and demulsification time dramatically. The wet-track abrasion test (WTAT) results demonstrated that mixtures with higher asphalt emulsion content and sand equivalent tended to have a higher early strength and a lower moisture susceptibility. © 2018 Elsevier Ltd

语种： 英文

作者： Zhang, J.*;Yan, S.;Qu, H.

期刊： International Journal of Hydrogen Energy,2018年43(3):1545-1565 ISSN：0360-3199

通讯作者： Zhang, J.

作者机构： [Qu, H.; Yan, S.; Zhang, J.] Changsha Univ Sci & Technol, Hunan Prov Key Lab Safety Design & Reliabil Techn, Changsha 410114, Hunan, Peoples R China.

通讯机构： [Zhang, J.] C;Changsha Univ Sci & Technol, Hunan Prov Key Lab Safety Design & Reliabil Techn, Changsha 410114, Hunan, Peoples R China.

关键词： Magnesium hydride;Thermodynamics;Kinetics;Catalysis;Nanoconfinement;Synergetic effects

摘要： Hydrogen is an ideal energy carrier because of its high chemical energy, environmental friendliness and renewability. In order to realize the safe, efficient and compact hydrogen storage, various solid-state hydrogen storage materials based on the physisorption or chemisorption of hydrogen have been developed over the past decades. Among them, magnesium hydride, MgH<inf>2</inf>, is identified as one of the most promising candidates due to its high hydrogen storage density, low cost and abundance of Mg element. However, the sluggish kinetics and high thermodynamic stability of MgH<inf>2</inf>result in its high operation temperature and low hydrogen sorption rate, impeding its practical application. In this article, the recent progress in catalysis and nanoconfinement effects on the hydrogen storage properties of MgH<inf>2</inf>is comprehensively reviewed. In particular, the synergetic roles of catalysis and nanoconfinement in MgH<inf>2</inf>are highlighted. Furthermore, the future challenges and prospects of emerging research for MgH<inf>2</inf>are discussed. It is suggested that the nonmetal-doped porous carbon materials could be a class of ideal additives to enhance the hydrogen storage properties of MgH<inf>2</inf>by the synergetic effects of catalysis and nanoconfinement.<br/> &copy;2017 Hydrogen Energy Publications LLC

语种： 英文

作者： Chen, Jian;Li, Chao;Zhang, Jian;Li, Cong;Chen, Jianlin;...

期刊： Materials,2018年11(7):1256- ISSN：1996-1944

通讯作者： Ren, Yanjie

作者机构： [Zhang, Jian; Ren, Yanjie; Li, Cong; Chen, Jian; Li, Chao; Chen, Jianlin] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha 410114, Hunan, Peoples R China.;[Zhang, Jian; Ren, Yanjie; Li, Cong; Chen, Jian; Li, Chao; Chen, Jianlin] Changsha Univ Sci & Technol, Educ Dept Hunan Prov, Key Lab Energy Efficiency & Clean Utilizat, Changsha 410114, Hunan, Peoples R China.;[Li, Cong] Guangxi Univ, Guangxi Key Lab Electrochem Energy Mat, Nanning 530004, Guangxi, Peoples R China.

通讯机构： [Ren, Yanjie] C;Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha 410114, Hunan, Peoples R China.;Changsha Univ Sci & Technol, Educ Dept Hunan Prov, Key Lab Energy Efficiency & Clean Utilizat, Changsha 410114, Hunan, Peoples R China.

关键词： lithium-ion batteries;copper current collector;first-principles method;adsorption

摘要： The copper current collector is an important component for lithium-ion batteries and its stability in electrolyte impacts their performance. The decomposition of LiPF6 in the electrolyte of lithium-ion batteries produces the reactive PF6, which reacts with the residual water and generates HF. In this paper, the adsorption and dissociation of H2O, HF, and PF5 on the Cu(111) surface were studied using a first-principles method based on the density functional theory. The stable configurations of HF, H2O, and PF5 adsorbed on Cu(111) and the geometric parameters of the admolecules were confirmed after structure optimization. The results showed that PF5 can promote the dissociation reaction of HF. Meanwhile, PF5 also promoted the physical adsorption of H2O on the Cu(111) surface. The CuF2 molecule was identified by determining the bond length and the bond angle of the reaction product. The energy barriers of HF dissociation on clean and O-atom-preadsorbed Cu(111) surfaces revealed that the preadsorbed O atom can promote the dissociation of HF significantly.

语种： 英文

作者： Jianming Zhang;Qianqian Huang;Honglin Wu;Yangchun Liu

期刊： International Journal of Embedded Systems,2018年10(2):120-125 ISSN：1741-1068

通讯作者： Zhang, Jianming(jmzhang@csust.edu.cn)

作者机构： [Jianming Zhang; Qianqian Huang; Yangchun Liu; Honglin Wu] Hunan Provincial Key Laboratory of Intelligent Processing of Big Data on Transportation, School of Computer and Communication Engineering, Changsha University of Science and Technology, Changsha Hunan Province, 410114, China

通讯机构： Hunan Provincial Key Laboratory of Intelligent Processing of Big Data on Transportation, School of Computer and Communication Engineering, Changsha University of Science and Technology, Changsha Hunan Province, China

关键词： kernel PCA network;kernel principal component analysis;KPCA;German traffic signs recognition benchmark;GTSRB

摘要： The classification of traffic sign images is easily affected by the change of weather, camera angles, occlusion, etc. The traditional image recognition methods not only require high image quality, but also need to find effective features manually. However, the convolutional neural networks can automatically extract high-level, abstract features which are robust to the variations. This paper presents a novel and effective traffic signs recognition approach via the kernel PCA network based on convolutional neural networks. The kernel PCA network uses two-layer convolutional network to extract abstract features, and convolution kernels in each layer are directly calculated by the kernel principal component analysis. After nonlinear mapping and pooling, support vector machines are applied to the final classification. The approach can achieve a high recognition rate on the German traffic signs recognition benchmark dataset containing reliable ground-truth data.

语种： 英文

作者： Peng, Jianxin;Tang, Huang*;Zhang, Jianren;Cai, Steve C. S.

期刊： Advances in Materials Science and Engineering,2018年2018:1-16 ISSN：1687-8434

通讯作者： Tang, Huang

作者机构： [Peng, Jianxin] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.;[Tang, Huang] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.;[Zhang, Jianren] Changsha Univ Sci & Technol, Sch Civil Engn & Architecture, Changsha 410114, Hunan, Peoples R China.;[Cai, Steve C. S.] Louisiana State Univ, Dept Civil & Environm Engn, Baton Rouge, LA 70803 USA.

通讯机构： [Tang, Huang] H;Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.

摘要： In order to further understand the carbonation process of concrete structures, the time- and temperature-dependent diffusion process of CO2 in concrete is simulated based on the law of the CO2 mass conservation, and a two-dimensional mass transfer equation is established for the CO2 diffusion in concrete. The concrete block is discretized into triangular elements, and the CO2 concentrations at different positions are calculated based on finite element method. A computational algorithm is programed through the Matlab platform. The time- and temperature-dependent property and difference of the CO2 concentration at different positions of the structure are considered in the proposed model. Then, an accelerated carbonation experiment is carried out using concrete blocks with different mix proportions to investigate the influence of the water-cement ratio and temperature on the concrete carbonation. The experimental results effectively verify the correctness of the finite element model, and the proposed finite element method reasonably simulates the concrete carbonation through calculating the carbonation in practical engineering compared with other methods in references. An experimental-numerical correlation has been performed. The ratio of carbonation depth at the corner of the concrete members to the other positions is about 1.35. The carbonation depth is increased about 1.9 times when the temperature changes from 20°C to 40°C. © 2018 Jianxin Peng et al.

语种： 英文

作者： Dai, Lizhao;Wang, Lei*;Deng, Ming;Wu, Binghui;Floyd, Royce W.;...

期刊： Journal of Bridge Engineering,2018年23(11):05018009-null ISSN：1084-0702

通讯作者： Wang, Lei

作者机构： [Wu, Binghui; Dai, Lizhao; Wang, Lei; Zhang, Jianren] Changsha Univ Sci & Technol, Sch Civil Engn & Architecture, 960 Wanjiali Rd, Changsha 410114, Hunan, Peoples R China.;[Dai, Lizhao] Univ Lorraine, CNRS, UMR 7239, LEM3, F-57045 Metz 01, France.;[Deng, Ming] Tianjin Transportat Res Inst, 25 Dongli Rd, Tianjin 300074, Peoples R China.;[Floyd, Royce W.] Univ Oklahoma, Sch Civil Engn & Environm Sci, 202 W Boyd St, Norman, OK 73019 USA.

通讯机构： [Wang, Lei] C;Changsha Univ Sci & Technol, Sch Civil Engn & Architecture, 960 Wanjiali Rd, Changsha 410114, Hunan, Peoples R China.

关键词： Bridge engineering;Post-tensioned concrete box beam;Strengthening;Serviceability;Prestressed steel wire ropes

摘要： Overloading, corrosion, and material aging deteriorate the structural performance of prestressed concrete (PC) bridges. Strengthening techniques are needed to improve the serviceability and extend the life of these deteriorating bridges. This study examined a strengthening technique with double-layer prestressed steel wire ropes (PSWRs) to enhance the serviceability of an existing post-tensioned concrete box beam for the first time. The tested box beam was removed from a demolished 20-year-old bridge. The service-level behavior of the beam, before and after strengthening, was evaluated using four-point flexural loading. The enhancement effects of the double-layer PSWR on the service-level behavior of the beam are discussed, including details on deflection, crack width, and reinforcing steel stress. Results show that PSWR strengthening is a feasible method for improving the serviceability of post-tensioned concrete box beams. The restraining effect of PSWR on crack development is more significant than the effect on deflection and reinforcing steel stress. Crack width, deflection, and reinforcing steel stress under the code-specified service load decreased by 50, 23, and 21%, respectively, after strengthening.

语种： 英文

作者： Zhang, Junhui;Peng, Junhui*;Chen, Yejuan;Li, Jue;Li, Feng

期刊： Advances in Civil Engineering,2018年2018 ISSN：1687-8086

通讯作者： Peng, Junhui

作者机构： [Peng, Junhui; Li, Feng; Zhang, Junhui; Li, Jue] Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410114, Hunan, Peoples R China.;[Chen, Yejuan] Changsha Commerce & Tourism Coll, Changsha 410001, Hunan, Peoples R China.

通讯机构： [Peng, Junhui] C;Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410114, Hunan, Peoples R China.

摘要： This study described a new methylene blue test to measure the methylene blue value (MBV) for 15 cohesive soils and established the relationship between MBV and plasticity index (PI) and between MBV and percent passing No. 200 sieve (P200), respectively. Thereafter, the soil-water characteristic curves (SWCCs) for 15 cohesive soils based on Fredlund and Xing's model were generated by the pressure plate test. Then, regression equations for determining the four fitting parameters in a previously developed SWCC equation by using the measured MBV were utilized to generate the SWCC for the cohesive soils. At the same time, the slope parameter, bf, in the SWCC equations was found to be associated with the moisture susceptibility of cohesive soils. A higher bf value indicates that the material is more moisture susceptible. In addition, a lower MBV/PI/P200 shows a lower suction at the same degree of saturation; on the other hand, a higher MBV/PI/P200 presents a higher suction. Therefore, the moisture-holding capacity of cohesive soils increases with increasing MBV, PI, and P200. Finally, the proposed estimation method was validated by a comparison between the four determined fitting parameters from MBV and the pressure plate test. © 2018 Junhui Zhang et al.

语种： 英文

作者： Zhang, Hongyu;Xia, Guanglin*;Zhang, Jian;Sun, Dalin;Guo, Zaiping;...

期刊： Advanced Energy Materials,2018年8(13):1702975- ISSN：1614-6832

通讯作者： Yu, Xuebin;Xia, Guanglin

作者机构： [Sun, Dalin; Yu, Xuebin; Zhang, Hongyu] Fudan Univ, Dept Mat Sci, Shanghai 200433, Peoples R China.;[Guo, Zaiping; Xia, Guanglin] Univ Wollongong, Inst Superconducting & Elect Mat, North Wollongong, NSW 2522, Australia.;[Zhang, Jian] Changsha Univ Sci & Technol, Coll Automot & Mech Engn, Changsha 410114, Hunan, Peoples R China.;[Sun, Dalin; Yu, Xuebin] Shanghai Innovat Inst Mat, Shanghai 200444, Peoples R China.

通讯机构： [Yu, Xuebin] F;[Xia, Guanglin] U;[Yu, Xuebin] S;Fudan Univ, Dept Mat Sci, Shanghai 200433, Peoples R China.;Univ Wollongong, Inst Superconducting & Elect Mat, North Wollongong, NSW 2522, Australia.

关键词： borohydrides;graphene;hydrogen storage;kinetics;magnesium hydride

摘要： Due to their ultrahigh theoretical capacity, metal borohydrides are considered to be one of the most promising candidate hydrogen storage materials. Their application still suffers, however, from high operating temperature, sluggish kinetics, and poor reversibility. Designing nanostructures is an effective way of addressing these issues, but seeking suitable approaches remains a big challenge. Here, a space-confined solid-gas reaction to synthesize Mg(BH4)2 nanoparticles supported on grapheme is reported, which serves as the structural support for the dispersed Mg(BH4)2 nanoparticles. More notably, density functional theory calculations reveal that graphene could weaken both the MgH bonds of MgH2 and BB bonds of B2H6, which could thermodynamically and kinetically facilitate the chemical transformation to synthesize Mg(BH4)2 with high purity. Because of the synergistic effects of both the significant reduction in particle size and the catalytic effect of graphene, an onset dehydrogenation temperature of ≈154 °C is observed for Mg(BH4)2 nanoparticles, and a complete dehydrogenation could be achieved at a temperature as low as 225 °C, with the formation of MgB2 as the by-product. This work provides a new perspective to tailoring the thermodynamics and kinetics of chemical reactions toward the favorable synthesis of functional inorganic materials. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

语种： 英文

作者： Zhang, Xuhui;Luo, Yuming;Wang, Lei*;Zhang, Jianren;Wu, Wenpeng;...

期刊： Construction and Building Materials,2018年172:185-195 ISSN：0950-0618

通讯作者： Wang, Lei

作者机构： [Wu, Wenpeng; Yang, Caiqian; Zhang, Xuhui] Xiangtan Univ, Coll Civil Engn & Mech, Xiangtan 411105, Peoples R China.;[Zhang, Xuhui; Wang, Lei; Luo, Yuming; Zhang, Jianren] Changsha Univ Sci & Technol, Sch Civil Engn & Architecture, Changsha 410114, Hunan, Peoples R China.

通讯机构： [Wang, Lei] C;Changsha Univ Sci & Technol, Sch Civil Engn & Architecture, Changsha 410114, Hunan, Peoples R China.

关键词： Bridge engineering;Flexural behavior;RC beam;Self-compacting concrete;Strengthening;Sustaining load

摘要： An experimental test is proposed in the present study to investigate the flexural behavior of damaged reinforced concrete (RC) beams strengthened by self-compacting concrete jacketing under different sustaining load. Eight RC T-beams with primary damages are designed and strengthened under different sustaining load. Then, the flexural testing test is employed to investigate the structural behavior of the strengthened beams. The influences of the sustaining load on beam response are clarified. The prediction method for the flexural capacity of the strengthened beams is also discussed. Results shows that the strengthening method proposed in the present study improves effectively the flexural behavior of beams, both in the stiffness after concrete cracking and the flexural capacity of the beams. Especially the flexural capacity, which becomes about twice as great. The interface treatment by surface roughening and rebar planting can provide effective bond strength between the substrate-new concrete. Sustaining load increase slightly the stiffness and the flexural capacity of beams until exceeding a critical value. The critical load was about 30% of the yield moment of beam before strengthening in the present test. The prediction of flexural capacity had high accuracy by the plastic limit analysis method and neglecting the strain-lag effects caused by the sustaining load during the strengthening process. © 2018 Elsevier Ltd

语种： 英文

作者： Zhang, Junhui;Li, Jue*;Yao, Yongsheng;Zheng, Jianlong;Gu, Fan

期刊： Construction and Building Materials,2018年183:346-355 ISSN：0950-0618

通讯作者： Li, Jue

作者机构： [Yao, Yongsheng; Zhang, Junhui; Li, Jue; Zheng, Jianlong] Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha, Hunan, Peoples R China.;[Gu, Fan] Auburn Univ, Natl Ctr Asphalt Technol, Auburn, AL 36849 USA.

通讯机构： [Li, Jue] C;Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha, Hunan, Peoples R China.

关键词： Biaxial shear test;California bearing ratio;Discrete element method;Geometric anisotropy;Graded crushed rocks;Shear behavior

摘要： To reveal the meso-mechanical mechanism of shear behaviors in the graded crushed rocks (GCRs), which are heterogeneous in geometry and widely used in the flexible pavement, a numerical technique was proposed to simulate the geometric anisotropy of the GCRs using randomly generated models. Then, studies on meso-mechanical responses during the loading were performed through the biaxial shear test and California bearing ratio (CBR) test. The results showed that the changes of both friction and anisotropy had a similar trend with the particle size enlarging in the dense assembly, which maintain stable when the size is less than 3.0 mm. In addition, the breaking sieve (BS) between coarse and fine aggregates was six times of the base diameter (0.8 mm). The predicted shear properties in macrostructure were in good agreement with those laboratory measurements. For the shear behaviors, the fractures and force chains were mainly distributed in the area of action that was limited by force size and side boundary. © 2018 Elsevier Ltd

语种： 英文

作者： Li, Dan*;Zeng, Lijiao;Wang, Yao;Yang, Jia;Zhang, Jingdong

期刊： CURRENT ANALYTICAL CHEMISTRY,2018年14(6):598-603 ISSN：1573-4110

通讯作者： Li, Dan

作者机构： [Wang, Yao; Li, Dan; Yang, Jia] Changsha Univ Sci & Technol, Sch Chem & Biol Engn, Changsha 410114, Hunan, Peoples R China.;[Zhang, Jingdong; Zeng, Lijiao] Huazhong Univ Sci & Technol, Sch Chem & Chem Engn, Wuhan 430074, Hubei, Peoples R China.

通讯机构： [Li, Dan] C;Changsha Univ Sci & Technol, Sch Chem & Biol Engn, Changsha 410114, Hunan, Peoples R China.

关键词： CdS;differential pulse voltammetry;graphene;kanamycin;photodegradation;single-stranded DNA.

摘要： Background: Overuse of antibiotics has become a serious ecological problem worldwide. It is necessary to monitor and control the pollution of antibiotics. Kanamycin is a representative antibiotic and has widely been used to treat a wide variety of infections. Although different methods have been established for kanamycin detection, it is still of great significance to develop new sensing approach to kanamycin monitoring. Methods: Graphene and Cadmium Sulphide (GR-CdS) nanocomposites were dispersed in 0.035% chitosan (CHIT) aqueous solution containing 0.52% acetic acid. Then, Glass Carbon Electrode (GCE) surface was coated with 5 µL of 1 mg·mL-1 GR-CdS suspension. The GR-CdS-CHIT modified electrode was immersed in 0.5 mg mL-1 single-stranded DNA (ssDNA) solution and 0.5 V potential was applied for 200 s to immobilize ssDNA on the electrode surface. Results: GR-CdS-CHIT dramatically promoted the electrochemical oxidation response of guanine residue in DNA. ssDNA exhibited higher oxidation peak current than double-stranded DNA (dsDNA). Under optimal conditions, ssDNA/GR-CdS-CHIT/GCE was prepared and used as the sensor to determine kanamycin, which showed a linear response to kanamycin in the concentration range of 0.10 to 1.0 mg mL-1 . The proposed sensor was successfully applied to monitoring photodegradation of kanamycin. Conclusion: ssDNA was effectively immobilized on GR-CdS-CHIT modified electrode and exhibited high electrochemical oxidation response. When kanamycin was present in the solution, the electrochemical oxidation peak current of ssDNA on the modified electrode declined due to the interaction between kanamycin and DNA. Thus, a novel electrochemical DNA biosensor for kanamycin was successfully developed. © 2018 Bentham Science Publishers.

语种： 英文

作者： Jin, Jiao*;Xiao, Ting;Zheng, Jianlong;Liu, Ruohua*;Qian, Guoping;...

期刊： Construction and Building Materials,2018年190:235-245 ISSN：0950-0618

通讯作者： Jin, Jiao;Liu, Ruohua

作者机构： [Xie, Juan; Xiao, Ting; Qian, Guoping; Wei, Hui; Zhang, Junhui; Liu, Hongfu; Jin, Jiao; Zheng, Jianlong] Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Changsha 410114, Hunan, Peoples R China.;[Liu, Ruohua] Cent S Univ, Sch Minerals Proc & Bioengn, Changsha 410083, Hunan, Peoples R China.

通讯机构： [Jin, Jiao; Liu, Ruohua] C;Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Changsha 410114, Hunan, Peoples R China.;Cent S Univ, Sch Minerals Proc & Bioengn, Changsha 410083, Hunan, Peoples R China.

关键词： Asphalt pavements;Ceramsite;Ethylene glycol distearate;Phase change;Poly(ethylene glycol)

摘要： Two kinds of phase change materials (PCMs), poly(ethylene glycol) (PEG) and ethylene glycol distearate (EGD), were incorporated with ceramsite (CS) to obtain the composite PCMs (CPCMs) by vacuum impregnation method. The morphology of the samples was observed using scanning electron microscope (SEM) and the chemical compatibility was characterized by X-ray diffraction (XRD) and Fourier transformation infrared (FTIR). The PEG and EGD could be retained by 42.1 wt% and 34.0 wt% into pores of the CS, which was calculated according to the curves of the thermogravimetric (TG) analysis. The thermal properties and thermal reliability of the CPCMs were investigated via differential scanning calorimetry (DSC). The phase change temperature (Tm) and heat of fusion (ΔHm) of prepared CPCMs are in the range of 54–60 °C and 29–50 J/g, respectively. The ΔHm of the CPCMs decreased obviously after 100 melting/freezing cycling, which was improved by encapsulating the prepared CPCMs with novolac epoxy resins (NER) to produce the encapsulated CPCMs (E-CPCMs). The results of the leakage experiment and storage/release test also show that the E-CPCMs have good thermal exudation stability and thermal storage/release properties. Based on all the results of the experiment, the encapsulated PEG/CS composite (E-PEG/CS) was added into the asphalt mixture to substitute the corresponding aggregate for simulating the actual temperature-adjusting effects. The results indicate that the maximum temperature reduction of the upper surface reaches about 9.1 °C at 210 min. Therefore, the E-CPCMs have the potential to decrease the high temperatures and temperature fluctuations in the asphalt pavements. © 2018 Elsevier Ltd

语种： 英文

作者： Yang, Yiming;Peng, Jianxin*;Zhang, Jianren;Cai, C. S.

期刊： Advances in Structural Engineering,2018年21(13):1951-1962 ISSN：1369-4332

通讯作者： Peng, Jianxin

作者机构： [Peng, Jianxin; Yang, Yiming; Zhang, Jianren] Changsha Univ Sci & Technol, Sch Civil Engn & Architecture, 960 WanJiali South Rd, Changsha 410114, Hunan, Peoples R China.;[Cai, C. S.] Louisiana State Univ, Dept Civil & Environm Engn, Baton Rouge, LA 70803 USA.

通讯机构： [Peng, Jianxin] C;Changsha Univ Sci & Technol, Sch Civil Engn & Architecture, 960 WanJiali South Rd, Changsha 410114, Hunan, Peoples R China.

关键词： Bayesian information criterion;bending moment;concrete compressive strength;reinforced concrete;scale of fluctuation;steel pitting factor

摘要： The scale of fluctuation (θ) of the material and geometrical parameters is the basis of studying the spatial variability of reinforced concrete structures. In this article, a new estimation method for the scale of fluctuation based on Bayesian information criterion is proposed. And based on the analysis of experimental data recorded on the three 36-year-old beams of the Jianggong Bridge and 246 corroded steel bars, the scale of fluctuation (θ) of concrete compressive strength (fc) and steel pitting factor (R) are estimated. The theoretical bending moment of three test beams are calculated considering the influence of the spatial distributions of fc, R, and other relative variables. The reasonableness and superiority of the Bayesian information criterion model than the auto-correlation function method and the semivariogram function model are verified by comparing the theoretical results with the measured bending moment of the three beams mentioned above. © The Author(s) 2018.

语种： 英文

作者： Yang, Hongming*;Zhang, Jun;Qiu, Jing;Zhang, Sanhua;Lai, Mingyong;...

期刊： IEEE Transactions on Smart Grid,2018年9(1):179-190 ISSN：1949-3053

通讯作者： Yang, Hongming

作者机构： [Zhang, Sanhua; Yang, Hongming; Zhang, Jun; Lai, Mingyong] Changsha Univ Sci & Technol, Hunan Prov Engn Res Ctr Elect Transportat & Smart, Hunan Prov Key Lab Smart Grids Operat & Control, Sch Elect & Informat Engn, Changsha 410114, Hunan, Peoples R China.;[Qiu, Jing] Univ Newcastle, Ctr Intelligent Elect Networks, Newcastle, NSW 2308, Australia.;[Dong, Zhao Yang] Univ Sydney, Sch Elect & Informat Engn, Sydney, NSW 2006, Australia.;[Dong, Zhao Yang] Elect Power Res Inst, CSG, Guangzhou 510080, Guangdong, Peoples R China.

通讯机构： [Yang, Hongming] C;Changsha Univ Sci & Technol, Hunan Prov Engn Res Ctr Elect Transportat & Smart, Hunan Prov Key Lab Smart Grids Operat & Control, Sch Elect & Informat Engn, Changsha 410114, Hunan, Peoples R China.

关键词： Demand response;Incentive compatible constraints;Load classification;Pricing plan

摘要： Appropriate pricing schemes are of great importance in terms of managing large-scale and distributed controllable loads in smart grids. In this paper, a practical pricing scheme is proposed to encourage different consumers to participate in demand response by providing them with a list of price plans. First, a classification algorithm is employed to divide consumers into different categories based on their individual information, such as marginal cost, upper limit of load adjustment, and elasticity coefficient. Afterwards, from the perspective of load service entity, a pricing model is formulated as a nonlinear programming problem, aiming to minimize the overall operation cost. Moreover, the Bayesian discrete probability distribution function is adopted to tackle the uncertainty of consumers' choosing behavior. Meanwhile, an incentive compatible constraint is added to capture the real private information of controllable loads, e.g., inducing them to bid as close as their marginal costs. According to the case studies on the IEEE 30-bus and 118-bus systems, the proposed pricing scheme is an effective demand response approach to managing controllable loads and achieving lower system cost. © 2016 IEEE.

语种： 英文