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bendable tube-shaped supercapacitor based on reduced graphene oxide and Prussian blue coated carbon fiber yarns for energy storage

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Journal of Energy Chemistry 2018年第3期27卷 866-873页

作者： mohd.Khalid Ana m.b.Honorato Department of macromolecular Science and Engineering Case Western Reserve University

Carbon fiber yarns（CFY） are promising as a new type of flexible building blocks for the construction of flexible architectures for the energy storage applications. The main hurdle with CFY is how to make them high energy and power capable by using economically and environmentally viable materials. Here,we report reduced graphene oxide（r GO） and Prussian blue（Pb） coated CFY, derived from a facile electrochemical process at room temperature for supercapacitor electrodes. The Pb coated CFY and r GO coated CFY electrodes exhibit the excellent gravimetric capacitance of 339 F/g and 160.2 F/g, respectively, in aqueous KCl electrolyte in three-electrode cell configuration. When we coupled these electrodes inside the flexible plastic tube and separated by the electrolyte wet filter paper in order to construct flexible architecture, the resulting device delivers excellent specific energy of 52.1 Wh/kg and 26.5 Wh/kg with offering specific power of 3100 W/kg and 14400 W/kg respectively, under a wide operating potential of1.8 V with excellent rate capability. The device shows high tolerance towards bending, and retained its efficiency to the capacitance after being bent at an angle of 360° for 200 bending cycles.

关键词： Carbon fiber yarns bendable supercapacitor Energy density Power density

Transient transport processes in deformable porous media

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Chinese Physics b 2011年第11期20卷 167-175页

作者： Cs.mészáros A.bálint Szent István University Department of Physics and Process Control Szent István University Department of Chemistry and Biochemistry

The basic partial differential equations relevant for convection-diffusion and convection-diffusion-wave phenomena arc presented and solved analytically by using the mAPLE symbolic computer algebra system. The possible general nonlinear character of the constitutive equation of the convection-discussion process is replaced by a direct posteriori stochastic refinement of its solution represented for Dirichlet-type boundary conditions. A thermodynamic analysis is performed for connecting the relaxation time constants and Jacobi-determinants of deformations at transient transport processes. Finally, a new procedure for general description of coupled transport processes on the basis of the formalism originally developed for convection-free phenomena is presented by matrix analysis methods in the Fourier space.

关键词： convection binary mixtures relaxation time matrix polynomials

A new apparatus to establish the spontaneous combustion propensity of coals and coal-shales

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International Journal of mining Science and Technology 2018年第4期28卷 643-649页

作者： m.Onifade b.Genc A.Carpede School of mining Engineering University of the Witwatersrand

Coal and coal-shale both tend to undergo spontaneous combustion under favourable atmospheric conditions. The Wits-Ehac index has been developed in South Africa since the late 1980's to test the spontaneous combustion liability of coal. However, in some cases, the Wits-Ehac index fails to produce tangible results when testing coal-shales. To overcome this problem, a new apparatus has been developed to test carbonaceous materials such as coal and coal-shale under chemical reactions with oxygen and an index has been obtained. This index is called the Wits-CT index. The equipment emulates the influence of oxygen adsorption on carbonaceous material for a period of 24 h without a heating *** Wits-CT index uses the total carbon content of the sample and the temperature variations obtained from the samples during reaction with oxygen to predict the spontaneous combustion liability. Eighteen samples have been analyzed using both indices and the results are in-line. It was found that coals and coal-shales with higher values of the Wits-CT index are more liable to spontaneous *** research on different coal-shales is underway in order to establish an extensive database for coal and coal-shales, together with known incidences of self-heating.

关键词： Coal Coal-shale Spontaneous combustion Wits-Ehac index Wits-CT index

Chemical forms and extractability of iron in sediments of three contrasting lakes of China and UK

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Journal of Environmental Sciences 2003年第6期15卷 728-733页

作者： Gibson C.E.,Stewart b.m. Key Laboratory of Terrestrial Ecological Process Institute of Applied Ecology Chinese Academy of Sciences Department of Agricultural and Environmental Science Queen's University belfast Shenyang 110016 China Newforge Lane belfast bT9 5PX UK

Iron is a limiting factor for the eutrophication of lakes, especially those lakes that are enriched with phosphorus. Extractability of iron in sediments of West Lake and Taihu Lake in China and Lower Lough Erne in Northern Ireland of UK was comparatively investigated on the basis of analysing chemical forms of iron using different extractants. It was shown that extractable iron in sediments of the lakes was greatly different using various extractants. Reactive iron or easily released iron such as “active" iron oxides, total free iron oxide and water-soluble iron was not high, only accounting for 0.01%—0.15% of total iron. The efficiency of the extractants for exchangeable iron was decreased in the sequence 0.1 mol/L HCl DTPA+TEA mixed solution > 1 mol/L NH 4OAc > 0.5 mol/L mgCl 2 = 0.5 mol/L CaCl 2. It seems that the complexion of iron by organic matter was not strong because the concentration of organically bound iron was significantly lower than the concentration it was forecasted. Extractable iron is not entirely consistent with or dependent on total iron in lake sediments. To a certain extent, phosphate can inhibit the release of iron in sediments of the lakes. The selection of extractants is thus the first key step to evaluate bioavailability of iron in lake sediments.

关键词： iron chemical form extractability lake sediment eutrophication

Environment friendly protocol for the synthesis of nitriles from aldehydes

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Chinese Chemical Letters 2010年第9期21卷 1025-1028页

作者： m.b.madhusudana Reddy m.A.Pasha Department of Studies in Chemistry Central College CampusBangalore University

A rapid and eco-friendly one-pot protocol for the synthesis of nitriles has been developed by treating various araldehydes bearing electron withdrawing as well as electron donating groups with hydroxylamine hydrochloride in the presence of non-toxic,non-corrosive and reusable zinc oxide（ZnO） as the catalyst under solvent-free microwave *** present approach offers the advantages of a clean reaction,simple methodology,employing readily available catalyst,short reaction duration（〈1 min）,high selectivity;and high yield（90-98%）.

关键词： Aldehydes Nitriles Solvent-free microwave irradiation benign procedure

Impurity effects on electrical conductivity of doped bilayer graphene in the presence of a bias voltage

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Chinese Physics b 2016年第7期25卷 316-323页

作者： E Lotfi H Rezania b Arghavaninia m Yarmohammadi Department of Physics Sanandaj Branch Islamic Azad University Department of Physics Razi University Department of Physics Kermanshah Branch Islamic Azad University Young researchers and Elite Club Kermanshah Branch Islamic Azad University

We address the electrical conductivity of bilayer graphene as a function of temperature, impurity concentration, and scattering strength in the presence of a finite bias voltage at finite doping, beginning with a description of the tight-binding model using the linear response theory and Green＇s function approach. Our results show a linear behavior at high doping for the case of high bias voltage. The effects of electron doping on the electrical conductivity have been studied via changing the electronic chemical potential. We also discuss and analyze how the bias voltage affects the temperature behavior of the electrical conductivity. Finally, we study the behavior of the electrical conductivity as a function of the impurity concentration and scattering strength for different bias voltages and chemical potentials respectively. The electrical conductivity is found to be monotonically decreasing with impurity scattering strength due to the increased scattering among electrons at higher impurity scattering strength.

关键词： bilayer graphene Green's function electrical conductivity

New turbulence modeling for air/water stratified flow

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Journal of Ocean Engineering and Science 2020年第1期5卷 55-67页

作者： m.Ghafari m.b.Ghofrani Department of Energy Engineering Sharif University of TechnologyAzadi Ave.TehranIran

The prediction of interfacial turbulence characteristics is one of the still challenging of two-phase stratified *** evaluation of some important parameters such as interfacial heat transfer coefficient based on turbulence kinetic energy and turbulence dissipation rate in some models,intensifies the importance of turbulence flow correct *** gradient of velocity and turbulence kinetic energy at the interface of two-phase stratified flow leads to a major overestimation or underestimation of flow characteristics without any special *** of a source function of turbulence eddy frequency at the interface is one of the common solution employed in past *** this solution remedies some shortcomings of traditional methods in smooth stratified flow,its application in wavy stratified flow needs the other *** examination of turbulence characteristics near the free surface reveals that,in addition to turbulence eddy frequency,the other source function of turbulence kinetic energy should be considered near the free ***,a new source function of turbulence kinetic energy is proposed at the interface based on flow *** new method has been employed for Fabre et al.(1987)experiment designed for air/water stratified *** results of simulation have a good agreement with experimental data and turbulence characteristic can be captured near the free surface.

关键词： Stratified flow Turbulence model Turbulence kinetic energy Source function

Scour prevention in bottomless arch culverts

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International Journal of Sediment Research 2012年第2期27卷 213-225页

作者： b.m.CROOKSTON b.P.TULLIS Utah Water Research Laboratory Utah State University8200 Old Main HillLoganUT 84322 Utah State University Utah Water Research Laboratory8200 Old Main HillLoganUT 84322

bottomless arch culverts are employed as ecological bridges at road crossings with their most common application being fish *** simulated culvert streambed should mimic the existing natural channel but be engineered to resist erosion during high flow *** provide some design guidance for simulated streambed stability in culverts,a culvert streambed stability study was conducted using a 0.61-m(2-ft) diameter smooth-walled bottomless arch culvert featuring streambed materials ranging in size from pea gravel to *** culvert entrance geometries over a range of headwater depths(unsubmerged and submerged inlets conditions) were *** riprap stone-sizing stability relationships were evaluated,relative to the experimental data,to determine their potential applicability to arched bottomless culverts streambed stability *** general observations are discussed regarding the location and extent of scour events in bottomless culverts and incipient motion velocity variations between the bottomless arched culvert and a rectangular flume for the same substrate materials.

关键词： Scour prevention bottomless arch culvert Fish passage Riprap Gravel streambed

Peristaltic flow with convective mass condition and thermal radiation

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Journal of Central South University 2015年第6期22卷 2369-2375页

作者： F.m.Abbasi T.Hayat b.Ahmad b.Chen Department of mathematics Comsats Institute of Information Technology Department of mathematics Quaid-I-Azam University 45320 Islamabad 44000 Pakistan Nonlinear Analysis and Applied mathematics (NAAm) Research Group Faculty of ScienceKing Abdulaziz University State Key Laboratory of Water Environment Simulation School of Environment Beijing Normal University

The primary objective of present investigation is to introduce the novel aspects of convective mass condition and thermal radiation in the peristaltic transport of fluid. magnetohydrodynamic(mHD) fluid was considered in a symmetric channel. Heat and mass transfer characteristics were analyzed in the presence of Soret and Dufour effects, and the results were presented via two forms of thermal radiation. The temperature, concentration and pressure rise per wavelength were examined. It is observed that the velocity slip and magnetic field parameters have opposite effects on the pressure rise per wavelength. Temperature of fluid is a decreasing function of the radiation parameter. Further, the temperature of fluid decreases by increasing the heat transfer biot number. It is notified that the heat transfer rate at the wall is a decreasing function of radiation parameter.

关键词： convective mass condition thermal radiation magnetohydrodynamic (mHD) fluid