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Effect of electrolytes on electrochemical properties of graphene sheet covered with polypyrrole thin layer

Progress in Natural science:materials International 2011年第6期21卷 460-466页

作者： Ya-meng CAI~(1,2.,Zong-yi QIN~1,Long CHEN~2.1.State Key Laboratory for Modification of Chemical Fibers and Polymer materials, Donghua university,Shanghai 2.162.,China {2. of Material science and engineering,Donghua university,Shanghai 2.162.,China [a] State Key Laboratory for Modification of Chemical Fibers and Polymer materials Donghua University Shanghai 201620 China [b] college of Material science and {2. Donghua University Shanghai 201620 China

Graphene sheet(GS) was successfully covered with a polypyrrole(PPy) thin layer through in situ chemical oxidative polymerization of pyrrole monomers in aqueous solution by using GS as a support material and ferric trichloride as an *** resulting nanocomposite was studied by field emission scanning electron microscopy(FE-SEM),Fourier transform infrared spectroscopy(FT-IR) and electrical measurements,including cyclic voltammetry(CV),galvanostatic charge/discharge experiment (GCD),and impedance spectroscopy(EIS).It has been found that the nanocomposite exhibited a typically curved and layer-like structure,and conformational change of PPy chains occurred due to the n-n stacking interaction between the graphitic structures in GS and aromatic rings of the PPy *** attention was paid to the effect of electrolytes on electrochemical properties of the nanocomposites,as expected,electrochemical performance was dependent on the nature of the electrolyte,and the neutral electrolytes containing alkali metal ions were found to be very suitable for GS/PPy *** with the pure PPy,the nanocomposite possessed larger specific capacitance and lower internal impedance,indicating that the nanocomposite can be a promising candidate as electrode material for supercapacitors.

关键词： nanocomposites graphene polypyrrole electrochemical property electrolyte

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A Series Piezoelectric Quartz Crystal Response Kinetics for *** Growth in the Presence of Cu(Ⅱ)

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Journal of Central South university 2000年第1期12卷 15-19页

作者： CHAI Li yuan 1,2.,WEI Wan zhi 2.YAO Shou zhuo 2.1. Department of Metallurgical science and engineering, Central South {2. of Technology, Changsha 410083, China 2. college of Chemistry and Chemical engineering, Hunan {2., Changsha 1. Department of Metallurgical science and engineering Central South University of Technology 410083 Changsha China 2. college of Chemistry and Chemical engineering Hunan University 410082 Changsha China

The kinetics on the growth of *** in the presence of Cu(Ⅱ) was studied using of series piezoelectric quartz crystal (SPQC). Arsenic ion inhibits the growth of *** , which is consistent with the previous results by other measuring methods. This further demonstrates that the SPQC can monitor the chemical activity of *** growth. Cupric ion accelerates the growth of *** . The mechanism was discussed, i. e., copper promotes the protein enzyme of *** , rusticyanin, to form over the range of cupric ion concentration studied. The reaction order of cupric ion in accelerating the bacterial growth is 0.067. The growth of *** is dependent on temperature, the apparent reaction activation energy decreases from 2..56 kJ/mol to 18.32.kJ/mol because of the addition of 10 mg/L Cu(Ⅱ) to the bacterial growth solution of pH 2.0 at initial inoculum of 10%.

关键词： series piezoelectric quartz crystal T.ferrooxidans growth kinetics sigmoid curve cupric ion

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Thermal Conductivity and Heat Transfer Coefficient of Concrete

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Journal of Wuhan university of Technology(materials {2.) 2011年第4期26卷 791-796页

作者：郭利霞 North China university of Water Resources and Electric Power

A very simple model for predicting thermal conductivity based on its definiensis was presented. The thermal conductivity obtained using the model provided a good coincidence to the investigations performed by other authors. The heat transfer coefficient was determined by inverse analysis using the temperature measurements. From experimental results, it is noted that heat transfer coefficient increases with the increase of wind velocity and relative humidity, a prediction equation on heat transfer coefficient about wind velocity and relative humidity is given.

关键词： thermal conductivity heat transfer coefficient relative humidity wind velocity

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Effect of Nd_2.e_(14)B/α-Fe Nanocomposite Permanent Magnets with a Combined Co and Nb Additions

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Journal of Wuhan university of Technology(materials {2.) 2009年第5期24卷 725-727页

作者：马瑞 School of materials science and Metallurgy {2. Guizhou University

Influence of Co＋Nb on the Nd8Fe82.o3Nb1B6 nanocomposite magnets was investigated by adding Co element combined with Nb element. Results show that the high temperature stability of two phases is increased. Adding Co＋Nb could improve the glass forming ability of the alloy, reduce the size of grains, increase the exchange coupling ability of two phases, and obviously increase the magnetic properties of the alloy. The optimal magnetic properties are Br=1.14 T, Hcj=32. kA/m, （BH）max=109.3 kJ/m^3

关键词： nanocomposite permanent magnets glass forming ability exchange coupling ability magnetic properties

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On the general expressions of finite Hankel transform

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science China(Physics,Mechanics & Astronomy) 2010年第11期53卷 2125-2130页

作者： JIANG Quan 1,2.& GAO CunFa 1 1 college of Aerospace engineering,{2. university of Aeronautics and Astronautics,{2. 2.0016,China 2.School of Civil engineering,Nantong university,Nantong 2.6019,China 1. college of Aerospace engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China2. School of Civil Engineering Nantong University Nantong 226019 China

The general expressions of finite Hankel transform are naturally deduced with the help of the property of Bessel *** equations in this paper can degenerate into three kinds of boundaries since all the coefficients in the boundary conditions are taken into *** results can be adopted in solving physics problems involving the finite Hankel transform.

关键词： hankel transform bessel function finite integral

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Influences of low-Ti substitution for La and Mg on the electrochemical and kinetic characteristics of AB_3-type hydrogen storage alloy electrodes

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science China(Technological sciences) 2010年第1期53卷 242-247页

作者： DONG ZhenWei1,2.WU YaoMing1,MA LiQun2.SHEN XiaoDong2.& WANG LiMin1 1 State Key Laboratory of Rare Earth Resource Utilization,Changchun Institute of Applied Chemistry,Chinese Academy of sciences,C hangchun 13002.,China 2.college of Material science and engineering,nanjing university of Technology,nanjing 2.0009,China 1. State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China2. College of Material Science and Engineering Nanjing University of Technology Nanjing 210009 China

The(La0.67Mg0.33)1-xTixNi2.75Co0.2.(x = 0,0.05,0.10,0.15 and 0.2.,at%) alloys were synthesized by arc melting and subsequent heat solid-liquid diffusing *** structure,electrochemical properties and kinetic characteristics of the alloys were investigated *** results showed that all the alloys mainly consisted of the(La,Mg)Ni3,LaNi5 phases,and the lattice parameters and the cell volumes of the(La,Mg)Ni3 and LaNi5 phases decreased with increasing Ti *** alloy electrodes could be activated to reach their maximum discharge capacity within five *** cycle life after 100 charge/discharge cycles(C100/Cmax) and the high-rate dischargeability at a discharge current density of 12.0 mA/g first increased and then *** the results showed that low-Ti content in AB3-type hydrogen storage alloys was beneficial to improvements of the overall electrochemical properties,and the optimum overall electrochemical performance of the alloy electrodes was obtained when x = 0.05.

关键词： AB3-type alloy metal hydride electrode microstructure electrochemical property kinetic characteristic

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Discrete Element Modeling of Asphalt Concrete Cracking Using a User-def ined Three-dimensional Micromechanical Approach

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Journal of Wuhan university of Technology(materials {2.) 2011年第6期26卷 1215-1221页

作者：陈俊 college of Civil and Transportation engineering Hohai University

We established a user-defined micromechanical model using discrete element method （DEM） to investigate the cracking behavior of asphalt concrete （AC）. Using the ＂Fish＂ language provided in the particle flow code in 3-Demensions （PFC3D）, the air voids and mastics in asphalt concrete were realistically built as two distinct phases. With the irregular shape of individual aggregate particles modeled using a clump of spheres of different sizes, the three-dimensional （3D） discrete element model was able to account for aggregate gradation and fraction. Laboratory uniaxial complex modulus test and indirect tensile strength test were performed to obtain input material parameters for the numerical simulation. A set of the indirect tensile test were simulated to study the cracking behavior of AC at two levels of temperature, i e, -10 ℃ and 15 ℃. The predicted results of the numerical simulation were compared with laboratory experimental measurements. Results show that the 3D DEM model is able to predict accurately the fracture pattern of different asphalt mixtures. Based on the DEM model, the effects of air void content and aggregate volumetric fraction on the cracking behavior of asphalt concrete were evaluated.

关键词： discrete element method asphalt concrete cracking behavior three-dimensional simulation micromechanics

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Effect of Pozzolanic Reaction Products on Alkali-silica Reaction

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Journal of Wuhan university of Technology(materials {2.) 2006年第3期21卷 168-171页

作者：魏风艳 Shanghai K. Wah Concrete Co.Ltd Shanghai 200030China

The effect of fly ash on controlling alkail-silica rection （ASR） in simudated alkali solution was studied. The expausion of mortar bars and the content of Ca（ OH）2.in cement paste cured at 80 °G for 91 d were measured. Traasmission electron microscopy （TEM） and high-resolution transmission electron microscot9 （HRTEM） were employed to study the microstructure of C-S-H. TEM/ energy dispersive spectroscopy （EDS） leas then used to determine the composition of C-S-H. The pore structure of the paste was analyzed by mercury intntsion porosimetry （MIP）. The results show that the contents of fly ash of 30% and 45% can well inhibit ASR. And the content of Ca（OH） 2.decreases with the increase of fly ash. That fly ash reacted with Ca（OH）2.to produce C-S-H with a low Ca/Si molar ratio could bind more Na^＋ and K^＋ ious, and produce a reduction in the amount of soluble alkali available for ASR. At the same time, the C- S- H produced by pozzolanic reaction converted large pores to snudler ones （ gel pores smaller than 10 nm ） to deusify the pore structure. Perhaps that could inhibit alkali trausport to aggregate for ASR.

关键词： alkali Ca/ Si molar ratio C-S-H alkali-silica reaction

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Study on the thermal stability and electrical properties of the high-k dielectrics (ZrO_2. _x(SiO_2._(1-x)

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science China(Technological sciences) 2009年第8期52卷 2222-2226页

作者： Lü ShiCheng1,2. YIN Jiang1,2. XIA YiDong2.3, GAO LiGang2.3 & LIU ZhiGuo2.3 1 Department of Physics, nanjing university, nanjing 2.0093, China 2.National Laboratory of Solid Sate Microstructures, nanjing university, nanjing 2.0093, China 3 Department of materials science and engineering, nanjing university, nanjing 2.0093, China 1. Department of Physics Nanjing University Nanjing 210093 China 2. National Laboratory of Solid Sate Microstructures Nanjing University Nanjing 210093 China 3. Department of materials science and {2. Nanjing University Nanjing 210093 China

(ZrO2.x(SiO2.1-x (Zr-Si-O) films with different compositions were deposited on p-Si(100) substrates by using pulsed laser deposition technique. X-ray photoelectron spectra (XPS) showed that these films remained amorphous after annealing at 800℃ with RTA process in N2.for 60 s. The XPS spectra indi- cated that Zr-Si-O films with x=0.5 suffered no obvious phase separation after annealing at 800℃, and no interface layer was formed between Zr-Si-O film and Si substrate. While Zr-Si-O films with x >0.5 suffered phase separation to precipitate ZrO2.after annealing under the same condition, and SiO2.was formed at the interface. To get a good interface between Zr-Si-O films and Si substrate, Zr-Si-O films with bi-layer structure (ZrO2.0.7(SiO2.0.3/(ZrO2.0.5(SiO2.0.5/Si was deposited. The electrical properties showed that the bi-layer Zr-Si-O film is of the lowest equivalent oxide thickness and good interface with Si substrate.

关键词： high-k dielectric film pulsed laser deposition pseudo ternary alloy

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Large eddies induced by local impulse at wall of boundary layer with pressure gradients

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Progress in Natural science:materials International 2008年第7期18卷 873-878页

作者： Changgen Lu a,b,*, Weidong Caob, Yanmei Zhang b, Jintao Pengb a college of Atmospheric science, {2. university of Information science & Technology, {2. 2.0044, China b college of Environmental science and engineering, hohai university, nanjing 2.0098, China college of Atmospheric science Nanjing University of Information Science & Technology Nanjing 210044 China college of Environmental science and {2. Hohai University Nanjing 210098 China

Large eddies induced by local impulse at the wall with pressure gradients in the boundary layer was studied by direct numerical sim- ulations. The results show that the amplitude evolution, the high and low speed stripes, the formation of streamwise vortices, the ejection and sweeping, inflexions and distortion at the mean velocity profiles, as well as other characteristics, are consistent with the experimental and other numerical results. It is also found that large eddies are easy to be excited with adverse pressure gradient in the boundary layer, and the growth of amplitudes, formation of streamwise vortices and the influencing area etc., are much larger than those with favorable pressure gradient in the boundary layer. In contrast, large eddies are hardly to be induced through local impulse disturbance at the wall with favorable pressure gradients in the boundary layer.

关键词： Boundary layer Pressure gradients Impulse Large eddies

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