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Ahmed Waqar Chowdhury Z. Z. Kazi S. N. Johan MR. Akram Naveed Oon C. S. Abdelrazek Ali H. 《Journal of Thermal Analysis and Calorimetry》2021,144(4):1517-1534
Journal of Thermal Analysis and Calorimetry - In recent decades, the growth of heat transfer using nanomaterials in the conventional base fluid has caught the attention of researchers... 相似文献
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In quasi-steady operation, convection currents in a Bridgmandevice, used for producing a semi-conductor crystal, createinhomogeneities that may make the crystal unusable. It has oftenbeen suggested that additional forces due to rotation or magnetismmight be efficacious in reducing the segregation of the elementsof the alloy. It has been found that, over a wide range of rotationrates, there is no improvement in performance due to rotationabout the vertical axis. However, numerical results that havebeen obtained previously (Lee & Pearlstein, J. Crys. Growth240, 2002) indicate that, when effects of centrifugal buoyancyare introduced, a substantial reduction in segregation is achieved.In the work reported here, by contrast, in which we extend previouslarge-Rayleigh-number asymptotic analysis to include centrifugalbuoyancy, we find no improvement in radial segregation, butrather increasing segregation with increasing rotation rate. 相似文献
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Dr. Khurram Saleem Joya Dr. Yasir F. Joya Prof. Kasim Ocakoglu Prof. Roel van de Krol 《Angewandte Chemie (International ed. in English)》2013,52(40):10426-10437
The development of new energy materials that can be utilized to make renewable and clean fuels from abundant and easily accessible resources is among the most challenging and demanding tasks in science today. Solar‐powered catalytic water‐splitting processes can be exploited as a source of electrons and protons to make clean renewable fuels, such as hydrogen, and in the sequestration of CO2 and its conversion into low‐carbon energy carriers. Recently, there have been tremendous efforts to build up a stand‐alone solar‐to‐fuel conversion device, the “artificial leaf”, using light and water as raw materials. An overview of the recent progress in electrochemical and photo‐electrocatalytic water splitting devices is presented, using both molecular water oxidation complexes (WOCs) and nano‐structured assemblies to develop an artificial photosynthetic system. 相似文献
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S.D. Gopal Ram G. Ravi MR. Manikandan T. Mahalingam M. Anbu Kulandainathan 《Superlattices and Microstructures》2011,50(4):296-302
In the present work, a controlled growth of ZnO nanostructures by manipulating Zn metal ion concentration by the chelating action of ethylene diaminetetra acetic acid in hydrothermal method is studied. EDTA produces metal–chelate complex by the formation of bidentate ligand with Zn2+ in the solution and diminishes the reactivity of Zn metal cations. Concentration of EDTA in the mother solution was varied in different ranges like 3, 5 and 10 mM while retaining the zinc metal salt and the NaOH concentration the same. Three different morphologies of wurtzite structured ZnO nanostructures such as nanorods-bunch, separate/discrete uniformly sized hexagonal nanorods and tapered flower petals like shapes are achieved by 3, 5 and 10 mM strengths of EDTA, respectively. The medium concentration 5 mM of EDTA is found to have moderate control over producing ZnO nanostructures of uniform diameter and a high aspect (length to diameter) ratio. An array of vertically aligned free standing ZnO nanorods with uniform spacing is successfully achieved by the addition of 5 mM of EDTA in the mother solution and the same is studied for its fluorescence property at an excitation of 325 nm and it has exhibited a characteristic UV emission of ZnO around 383 nm. 相似文献
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A novel sol-gel/laser-induced technique (SGLIT) has been developed to form nanocrystalline titanium dioxide (TiO2) based thin films with an improved antibacterial performance. TiO2 precursor films loaded with W+6 and Ag+2 ions (W–TiO2, Ag–TiO2) were prepared separately by sol-gel method and spin-coated on microscopic glass slides. As-dried films were subjected to
KrF excimer laser pulses at optimized parameters to generate mesoporous anatase and rutile phases at room temperature. The
anatase phase was obtained after irradiation with 10 laser pulses only at 75–85 mJ/cm2 fluence in W–TiO2 films. However, higher number of laser pulses and higher W+6 content favored the formation of rutile. Whereas Ag–TiO2 films exhibited anatase up to 200 laser pulses at the same fluence. The films were characterized by using XRD, FEG-SEM, TEM
and UV-Vis spectrophotometer to investigate the crystallographic structure, phase transformation, surface morphology, film
thickness and the optical properties. A crystallite size of approximately 20 nm was achieved from the anatase prepared by
SGLIT. The films exhibited an enhanced antibacterial function against E-Coli cells under the UV excitation. 相似文献
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P.S. Pizani M.R. Joya F.M. Pontes L.P.S. Santos M. Godinho E.R. Leite E. Longo 《Journal of Non》2008,354(2-9):476-479
Intense photoluminescence in the visible region was observed at room temperature in standard soda-lime-silica glass powder, mechanically milled in a high-energy attrition mill. The emission band maximum shows an interesting dependence on the exciting wavelength, suggesting the possibility to tune the PL emission. These findings indicate that the photoluminescence may be directly related to unsatisfied chemical bonds correlated with the high surface area. The Raman scattering and ultraviolet–visible optical reflectance measurements corroborate this assertion. Transmission electron microscopy measurements indicate that samples milled more than 10 h present the formation of nanocrystallites with about 10–20 nm. 相似文献
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We propose a way to manipulate the landscape of the superconducting condensate in thin films via stripe-like (1D) and checkerboard (2D) periodic patterns. Our approach is based on the spatially localized heating of the superconductor, which is reflected in sinusoidal variations of the local temperature, which can be produced via, e.g., a focused laser beam or nanoheaters. This simple approach provides a very good alternative for modulation of the vortex collective, emerging in the type-II superconductors as a natural response to the applied magnetic field and the transport current, which was, up to now, controlled mainly via nanofabricated static pinning centers, whose distribution cannot be changed once the landscape is defined. 相似文献