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We have developed a supercapacitor electrode composed of CuS microspheres with polypyrrole (PPy) uniformly inserted into the sheet-like subunit structure and coated onto the CuS surface to enhance the pseudocapacitive performance. Novel sphere-like CuS particles with intertwined sheet-like subunit structure are fabricated by a solvothermal approach without any surfactant or template. A CuS@PPy composite electrode is prepared by in situ oxidation polymerization of pyrrole in the presence of the CuS suspension. The CuS@PPy composite (CuS content is 16.7 wt%) exhibits a high specific capacitance of 427 F g -1 (at 1 A g-1) and its capacitance can still retain 88% after 1000 cycles. © The Royal Society of Chemistry.

Zhang W.,Jiangnan University | Jiang P.,Jiangnan University | Wang Y.,Jiangnan University | Zhang J.,Lanzhou City University | Zhang P.,Jiangnan University
Catalysis Science and Technology | Year: 2015

Two kinds of novel functional covalent organic frameworks were assembled with the porphyrin building block and terephthalaldehyde or squaric acid via bottom-up approach. Here, our reported covalent porphyrinic frameworks with coordinated manganese(iii) ions (Mn-CPF-1 and Mn-CPF-2) present promising catalytic properties for the selective oxidation of olefins. © The Royal Society of Chemistry 2015.

Wang T.-P.,Lanzhou Jiaotong University | Wang L.-B.,Lanzhou Jiaotong University | Li B.-Q.,Lanzhou City University
Energy and Buildings | Year: 2013

Considering convection heat transfer between inside and outside surfaces of the glazing and conduction heat transfer of glass sheet, this paper presents a mathematical model of the long-wave radiation heat transfer between inside room surfaces and outside environmental surface through a glazing. The effects of three main factors on the overall heat flux are evaluated. Three main factors are the glass transmittance of long-wave radiation, convection heat transfer coefficient of inside and outside glass surface, the difference between the inside room surface temperature and the indoor air temperature as well as the difference between the outside environmental surface temperature and the outdoor air temperature. If the long-wave radiation transmittance approaches to 0.1, the effects of the transparence radiation of glass or some polymer material on the overall heat flux are obvious and cannot be ignored. The effects of convection heat transfer coefficient of inside and outside glass surface on the overall heat flux are relatively weak. If the temperature difference between the surface and air temperature is less than 2 °C, the effects on the overall heat flux and the role of the transparence radiation are weak. But if the difference is large, the effects are obvious and significant. © 2013 Elsevier B.V.

Wu H.,Lanzhou City University | Zhang Z.,Lanzhou University
Dynamical Systems | Year: 2011

In this article, we study the long-time behaviour of the nonclassical diffusion equation u t-Δu t-Δ u+f(u)= g(x) with critical nonlinearity, where the initial data and the external forcing term g only belongs to H -1(Ω). Some asymptotic regularity of solutions in H 1+ν(Ω) (for any ν∈[0, min{1,N/2-1})) has been proved, although its stationary solutions (and so the global attractor) only belong to H 0 1(Ω). © 2011 Copyright Taylor and Francis Group, LLC.

Peng H.,Northwest Normal University | Ma G.,Northwest Normal University | Mu J.,Northwest Normal University | Sun K.,Lanzhou City University | Lei Z.,Northwest Normal University
Journal of Materials Chemistry A | Year: 2014

Asymmetric supercapacitors (ASCs) with high energy density are assembled based on the pseudocapacitance of both electrodes, which use polyaniline (PANI) nanotubes as positive electrodes and MoO3 nanobelts as negative electrodes in a 1 M H2SO4 aqueous electrolyte. The assembled novel PANI//MoO3 ASC device with an extended operating voltage window of 2.0 V, in spite of the use of an aqueous electrolyte, exhibits excellent performance such as a high specific capacitance of 518 F g -1 at a current density of 0.5 A g-1, reaching an energy density as high as 71.9 W h kg-1 at a power density of 254 W kg -1 and good cycling stability. © 2014 the Partner Organisations.

Zheng X.P.,Lanzhou City University
Advanced Materials Research | Year: 2013

A novel model consisting of basic micro-processes has been developed on the basis of the classic diffusion theory. It is first time that the concept of exchange rate has introduced, and the growing process of surfactant-mediated epitaxial thin-film growth has been simulated with Kinetic Monte Carlo (KMC) technique. The results of simulation found that the exchange reaction of RLA model is a combination of the basic micro-processes. The majorities of exchange are not complete position exchange and the exchange rate doesn't always equal one. Both surfactant atoms and adatoms would diffuse from one layer to another. The diffusion happens mostly between single atoms and the diffusing atoms increase with substrate temperature. © (2013) Trans Tech Publications, Switzerland.

Li K.-M.,Lanzhou City University
Indian Journal of Physics | Year: 2013

By using reductive perturbation method, we derive a Korteweg-de Vries-type equation and a modified Nonlinear Schrödinger equation for dust lattice wave in a weakly inhomogeneous dust plasma crystal. It seems that amplitude and velocity of dust lattice solitary wave decay exponentially. The modulational instability of this dust lattice envelope wave is investigated. It is found that the wave is modulational stable under certain conditions and unstable otherwise. © 2013 IACS.

Tong C.,Lanzhou City University
Yingyong Lixue Xuebao/Chinese Journal of Applied Mechanics | Year: 2016

To the oil production, the flexible sucker rod is of high efficiency, low cost, convenient installation and maintenance, it becomes the top one of the main development directions. Carbon fiber material is of light flexibility, high tensile strength and becomes the best choice for the flexible sucker rod. Every 100m it drops downward in oil well, the temperature rises about 3℃, so one may wonder how the tensile properties of carbon fiber will be and whether they are affected by the crude oil medium corrosion. According to the oil well temperature conditions, the Nissan AG -10kN universal testing machine is employed to get the tensile strength of the 6K T300 carbon fiber at different temperatures of 20℃, 40℃, 60℃, 80℃ and 98℃. The tensile strength measured at 98℃ is stable and it reaches the highest at 40℃~60℃ when underground temperature changes. By another test, it is found that the carbon fiber material is sensitive to corrosion of crude oil by changing the soaking time(until 3 days, 5 days, 10 days, 30 days, 60 days, 180 days). Finally,it is suggested to study the corrosion of crude oil further. © 2016, Editorial Department of CJAM. All right reserved.

Tong C.,Lanzhou City University
IOP Conference Series: Materials Science and Engineering | Year: 2015

A experiment plan was designed according to the working conditions of sucker rod and the requirements for pump depth in 3000 m in the oil field, the tensile strength for 6K T300 under a normal temperature and high temperature was measured by using universal testing machine, and then, the resistance to corrosion for a crude oil was verified by measuring the tensile strength for 6K T300 after crude oil immersion at a certain time, and the conclusions are that the material is sensitive relatively to corrosion of crude oil and that the tensile strength of the 6K T300 compared with similar products is lower, a proposal to the GH company that to meet the need of oil field production instead of the rigid rod the tensile strength and corrosion resistant for a crude of the T300 6 k materials have to do further efforts was pointed out.

Wang P.,Lanzhou City University | Zheng X.,Lanzhou City University
Powder Technology | Year: 2011

Pd nanoparticles supported in mesoporous silica SBA-15 (or Pd/SBA-15 nanocomposites) were prepared by ion-exchange with cationic Pd precursor in an alkaline solution on an uncalcined silica. The high Pd loading in these nanocomposites can be achieved up to 5.21. wt.% by adjusting the pH value of the solution. The surface area and the pore volume decrease with increasing Pd loading. The Pd nanoparticles equal to or smaller than 6. nm in size in the nanocomposites are distributed in the channels of the mesoporous SBA-15. The Pd/SBA-15 nanocomposites exhibit excellent catalytic activities and high reuse ability in air for the Heck carbon-carbon coupling reactions. © 2011 Elsevier B.V.

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