共查询到20条相似文献,搜索用时 31 毫秒
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L. Miao Y. Ieda S. Tanemura Y.G. Cao M. Tanemura Y. Hayashi 《Science and Technology of Advanced Materials》2013,14(6):443-447
Well-aligned zinc oxide (ZnO) nanorods were densely grown on Si substrate using ZnO thin-film seed layer without any catalysts and/ or additives by a simple solid–vapour phase thermal sublimation technique. The growth mechanism can be interpreted as self-catalyst of zinc particles based on vapour–solid (VS) mechanism. High-resolution transmission electron microscopy (HRTEM) image and selected area electron diffraction (SAED) pattern confirmed that the single-crystalline growth of the nanorods were preferentially along c-axis of hexagonal crystal system. High-crystal quality ZnO nanorods with strong near band edge emission centred at 380 nm can be achieved on Si substrate by the introduction of sufficient oxygen during the nanorod growth processing. 相似文献
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Adsorption of nano‐scaled titanium(IV) oxide particles on electroplated zinc is performed by a simple dip‐coating technique in an aqueous titanium(IV) oxide suspension prepared with a stirred media mill. X‐ray photoelectron spectroscopy, scanning electron microscopy and X‐ray fluorescence spectroscopy are carried out to investigate the composition of the zinc surface and the thickness and porosity of the adsorbed titania films. The zinc surface formed during the electrodeposition process is of oxyhydroxide nature and the thickness of the adsorbed titania particle layer is controlled by the pH value and the solid concentration of the suspension. In the range of 10 wt.%–30 wt.% titanium(IV) oxide, a linear dependence between the titania film thickness and the solid content of titania particles in the suspension is found. Highest film thicknesses are obtained in alkaline media (pH≥9). At 13.5 wt.% titania particles and pH values below pH = 2.4, the titania particle film is not closely packed and the zinc layer underneath is still visible in electron microscopy, which is a prerequisite for imbedding these particles by a thin second zinc layer for formation of a robust chromium(VI)‐free passivation layer containing the titania particles. 相似文献
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Cagdas Baday Metin Yurddaskal Metin Ozgul Mehmet Zor Erdal Celik 《Journal of Materials Science: Materials in Electronics》2017,28(23):17468-17481
The objective of this study is to produce the thermoelectric (TE) module called as a Peltier module or element using new and promising materials that work at high temperature for generation of electricity with thermoelectric energy conversion from waste heat at high temperatures. Peltier modules used commercially nowadays can work at relatively low temperatures and their efficiency increase in proportion to the temperature difference between the surfaces of the modules. They consist of a pair of p- and n-type semiconductor. In this study, calcium cobalt oxide was chosen as a p-type semiconductor whilst zinc oxide was chosen as n-type semiconductor. Pure and aluminum-doped zinc oxide and silver-doped calcium cobalt oxide powders were synthesized via sol–gel processing successfully. The obtained powders were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), fourier transform infrared (FTIR), differential thermal analysis-thermogravimetry (DTA-TG), and scanning electron microscopy (SEM). In addition, the particle size distribution of the powders obtained via sol–gel processing was determined using a particle size analyzer. One and two leg oxide thermo-electric modules consisting of one pair of p-type 0.03 percent silver doped calcium cobalt oxide and n-type 0.02 percent aluminum doped zinc oxide bulks of 25 square millimeter cross-section and 3 millimeter heights were constructed. The thermoelectric module constructed was tested at high temperatures, and compared to other similar oxide modules reported in literature. Ultimately, the thermal stress and alteration of thermal stress depending on the leg length and side length of semiconductors were calculated using the finite element analysis (FEA) model in ANSYS 15.0 software. According to the results of the analysis, TE module was optimized in terms of mechanical behavior. 相似文献
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The carbothermic reduction of zinc sulfide in the presence of calcium oxide has been studied using X-ray diffractometry (XRD), scanning electron microscopy (SEM) and surface area measurements. The results of XRD indicated that zinc sulfide was first transformed from β type to α type, then reacted to give an intermediate product of zinc oxide before being reduced finally to zinc vapor. The sulfur of zinc sulfide was scavenged as calcium sulfide which remained in the solid, and carbon black formed carbon monoxide. SEM showed that the zinc containing particles and carbon grains shrank gradually; the calcium containing grains swelled and sintered during the reaction. The surface area of the solid sample decreased drastically in the initial stage and then increased with reaction time; the pore volume of the solid sample was also reduced much faster initially and then increased slowly. The average pore diameter, however, increased remarkably in the initial stage, decreased and then leveled off. These results were explained by considering the phase transformation of zinc sulfide, escape of zinc vapor, gasification of carbon and expansion and sintering of calcium sulfide. A reaction mechanism and model are proposed to explain the variations in chemical composition and physical properties of the solid sample during the reaction. 相似文献
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Thermodynamic analysis of the selective carbothermic reduction of electric arc furnace dust 总被引:1,自引:0,他引:1
Pickles CA 《Journal of hazardous materials》2008,150(2):265-278
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P. A. Luque C. A. Soto-Robles O. Nava C. M. Gomez-Gutierrez A. Castro-Beltran H. E. Garrafa-Galvez A. R. Vilchis-Nestor A. Olivas 《Journal of Materials Science: Materials in Electronics》2018,29(12):9764-9770
This work addresses a low cost, non-toxic green synthesis of zinc oxide nanoparticles prepared using different amounts of Citrus sinensis extract. The zinc oxide nanoparticles presented the Zn–O bond at 618 cm?1, a crystalline growth in a purely hexagonal wurtzite crystal structure, and different size and shape homogeneity depending on the amount of extract used. The band gap of the ZnO was at around 2.91 eV for all samples. The photocatalytic degradation studies were carried out using methylene blue with the zinc oxide nanoparticles under UV light; where sample M2 presented a degradation of around 83% at 120 min. These results presented a better degradation rate than commercially available zinc oxide nanoparticles. 相似文献
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L. Miao Y. Ieda S. Tanemura Y.G. Cao M. Tanemura Y. Hayashi S. Toh K. Kaneko 《Science and Technology of Advanced Materials》2007,8(6):443-447
Well-aligned zinc oxide (ZnO) nanorods were densely grown on Si substrate using ZnO thin-film seed layer without any catalysts and/or additives by a simple solid–vapour phase thermal sublimation technique. The growth mechanism can be interpreted as self-catalyst of zinc particles based on vapour–solid (VS) mechanism. High-resolution transmission electron microscopy (HRTEM) image and selected area electron diffraction (SAED) pattern confirmed that the single-crystalline growth of the nanorods were preferentially along c-axis of hexagonal crystal system. High-crystal quality ZnO nanorods with strong near band edge emission centred at 380 nm can be achieved on Si substrate by the introduction of sufficient oxygen during the nanorod growth processing. 相似文献
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Indium-doped zinc oxide thin films deposition was performed by the sol-gel technique using homogeneous and stable solutions of zinc acetate 2-hydrate and indium chloride in ethanol. Films were spin coated onto glass substrates. After drying and after a heat treatment at 450 °C, highly transparent (80%-90%) films were obtained. The effect on the structural, morphological, optical and electrical thin films properties of the dopant concentration was investigated. The temperature dependencies of the electrical conductivity under vacuum and in open atmosphere were analysed and discussed. 相似文献
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This study presents a column solid phase extraction procedure based on column biosorption of Cu(II), Zn(II) and Pb(II) ions on Penicillium digitatum immobilized on pumice stone. The analytes were determined by flame atomic absorption spectrometry (FAAS). The optimum conditions such as: pH values, amount of solid phase, elution solution and flow rate of sample solution were evaluated for the quantitative recovery of the analytes. The effect of interfering ions on the recovery of the analytes has also been investigated. The recoveries of copper, zinc and lead under the optimum conditions were found to be 97+/-2, 98+/-2 and 98+/-2%, respectively, at 95% confidence level. For the analytes, 50-fold preconcentration was obtained. The analytical detection limits for Cu(II), Zn(II) and Pb(II) were 1.8, 1.3 and 5.8 ng mL(-1), respectively. The proposed procedure was applied for the determination of copper, zinc and lead in dam water, waste water, spring water, parsley and carrot. The accuracy of the procedure was checked by determining copper, zinc and lead in standard reference tea samples (GBW-07605). 相似文献
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Organic photovoltaic devices based on a blend of poly(3-hexylthiophene) and a fullerene have been studied by inserting oriented zinc oxide nanopillars which were fabricated by a new method at low temperature (343?K). The dependence of the photovoltaic performance on the zinc oxide morphology was investigated, and it is concluded that the oriented zinc oxide nanopillar array plays an important role in collecting photogenerated electrons and acts as a conducting path to the electrode. Insertion of the oriented zinc oxide nanopillars in the photovoltaic cells produced enhanced performance with a power conversion efficiency of 1.22% under AM1.5 illumination. 相似文献
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Sotoudeh Sedaghat-Hoor 《Particulate Science and Technology》2013,31(7):897-903
ABSTRACTA magnesium-aluminum layered double hydroxide was synthesized with co-precipitation method and zinc salt was impregnated on it. The final product was calcined and used as a catalyst in the transesterification reaction to produce biodiesel from waste cooking oil. Both MgAl hydrotalcite and Zn impregnated compound (Zn/MgAl(O)) were characterized using X-Ray Diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy (EDS) techniques. High surface area and nanometric pore size of Zn/MgAl(O) was determined using Bruneure-Emmett-Teller N2 physisorption technique. Another fully co-precipitated ZnMgAl mixed oxide was synthesized by and compared with Zn impregnated product in the transesterification reaction. The reactions were performed at 65°C using 9:1 methanol to oil ratio for 3?h. The biodiesel yields were measured by gas chromatography (GC). Leaching amounts of surface active components of as-synthesized mixed metal oxides were determined by EDS and ICP analysis of used catalyst. Zn impregnated catalyst showed 78.45% conversion of the fatty acid to methyl esters and just 1.16% leaching of Zn was observed, that is much lower than the diminishing in the co-precipitated compound. Finally, the reaction and leaching proofs and the effect of synthesis method on the firmness of catalyst were discussed. 相似文献
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Boron doped zinc oxide thin films (∼80 nm) were deposited onto pure silica glass by sol-gel dip coating technique from the precursor sol/solution of 4.0 wt.% equivalent oxide content. The boron concentration was varied from 0 to 2 at.% w.r.t. Zn using crystalline boric acid. The nanostructured feature of the films was visualized by FESEM images and the largest cluster size of ZnO was found in 1 at.% boron doped film (B1ZO). The presence of mixed crystal phases with hexagonal as major phase was identified from XRD reflections of the films. Particle size, optical band gap, visible specular reflection, room temperature photoluminescence (PL) emissions (3.24-2.28 eV), infra-red (IR) and Raman active longitudinal optical (LO) phonon vibration were found to be dependent on dopant concentration. For the first time, we report the room temperature fine structured PL emissions as phonon replicas originated from the LO phonon (both IR and Raman active) in 1 at.% boron doped zinc oxide film. 相似文献
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Preparation of self-assembled zinc oxide nanoparticles multilayer films under ultrasonic irradiation
Zinc oxide nanoparticles were synthesized and self-assembled on the reactive surface of a glass slide functionalized with (3-mercaptopropyl)-trimethoxysilane under ultrasonic irradiation. The structure, morphology, and optical property of the zinc oxide nanoparticles were investigated by TEM, XRD, and UV-vis spectroscopy. The functionalized glass slide was soaked in an aqueous solution which dispersed zinc oxide nanoparticles under ultrasonic irradiation. Zinc oxide multilayer films grew up to several layers (up to 5 layers) depending on the immersion time. The self-assembled zinc oxide nanoparticles multilayer films were characterized using UV-vis spectroscopy and SEM. Ultrasonic irradiation was an efficient method to make multilayer films on the functionalized glass slide with zinc oxide nanoparticles. 相似文献
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The purpose of this research was to determine the fate and behavior of heavy metals co-disposed with municipal waste under methanogenic conditions. Two landfill simulating reactors, one with leachate recirculation and the other without, were operated in a constant room temperature at 32 degrees C. These reactors were filled with shredded and compacted municipal solid waste having a typical solid waste composition of Istanbul region. After the onset of the methanogenic conditions, the selected heavy metals including iron, copper, nickel, cadmium and zinc were added according to the amounts suggested for co-disposal under the directives of the Turkish Hazardous Waste Control Regulations. The results of the experiments indicated that about 90% of all heavy metals were precipitated from the reactors within the first 10 days due to the establishment of highly reducing environment and the formation of sulfide from sulfate reduction which provided heavy metal precipitation. No inhibition to the biological stabilization was observed. 相似文献
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Measurements of surface potential and surface conductivity in zinc oxide thin films in contact with eosin dye show that two regimes of spectral sensitization are involved under vacuum conditions. The dye molecules at the interface trap conduction electrons in the dark at a site close in energy to the dye ground state leading to a Schottky barrier. The return of the trapped electrons from the excited dye is held responsible for “thin layer” sensitization. With “thick” dye layers an additional contribution arises from charge transfer between the photoconducting solid dye and the zinc oxide substrate, in a direction which tends to equilibrate the Fermi levels in the two media, The decay of the ”thick layer” sensitized photoeffect is identical to the decay of the field effect in undyed zinc oxide films and is controlled by zinc oxide surface states. 相似文献
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L. Suganya B. Sundaresan G. Sankareswari K. Ravichandran B. Sakthivel 《Journal of Materials Science: Materials in Electronics》2014,25(1):361-368
Aluminium doped zinc oxide thin films were deposited onto glass substrate using spin coating technique. The effects of Al doping on structural, optical and electrical properties of these films were investigated. X-ray diffraction analysis showed that all the thin films were of polycrystalline hexagonal wurtzite structure with (002) as preferential orientation except 2 at.% of Al doped ZnO films. The optical band gap was found to be 3.25 eV for pure ZnO film. It increases up to 1.5 at.% of Al doping (3.47 eV) and then decreased slightly for the doping level of 2 at.% (3.42 eV). The reason for this widening of the optical band gap up to 1.5 at.% is well described by Burstein–Moss effect. The photoluminescence spectra of the films showed that the blue shift and red shift of violet emission were due to the change in the radiative centre between zinc vacancy and zinc interstitial. Variation in ZnO grain boundary resistance against the doping concentration was observed through AC impedance study. 相似文献
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Laura Cocheci Lavinia Lupa Marius Gheju Alin Golban Radu Lazău Rodica Pode 《Clean Technologies and Environmental Policy》2018,20(5):1105-1112
Hot-dip galvanizing process is used worldwide to protect the steel or iron pieces from corrosion. This process is a large generator of waste, considered one of the so-called dirty industries. One of the important wastes, in terms of quantity, is zinc ash that contains a mixture of metallic zinc and zinc oxide with a total content of zinc between 70 and 90%. The aim of this study is the preparation and characterization of a series of Zn R –Al–CO3 (R?=?2–4) layered double hydroxides (LDH) by using as zinc precursor the zinc chloride obtained after hydrochloric acid leaching of fine-grained zinc ash. Results presented herein clearly demonstrated that characteristics of the synthesized samples are close to those of similar materials synthesized starting from analytical grade reagents. At the same time, it was observed that impurities existent in the zinc chloride solution prepared by zinc ash leaching (Pb, Fe, Ca), are found at traces in the synthesized LDH materials; therefore, they have no significant influence on the obtained LDH structure and properties. By this approach, several important benefits may be simultaneously achieved: (1) preventing the pollution associated with hot-dip galvanizing process wastes, (2) obtaining of valuable products with minimized costs, keeping in mind that LDH have multiple utilizations at industrial scale, (3) saving energy and material costs, and (4) increase of product competitiveness with respect to the circular economy. 相似文献
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In the present work, we investigate the surface, and bulk structural properties of composite cupric oxide ribbons, and zinc oxide particles. The composites are synthesized using the technique of solution combustion. Crystallographic phases are confirmed using the x-ray diffraction technique and proved the formation of monoclinic cupric oxide and hexagonal zinc oxide crystallites. Scanning electron microscope and high-resolution transmission electron microscope are used to examine the morphology of the prepared materials. Composite mixtures of raw particles cupric oxide and zinc oxide are used as benchmark morphologically-alike composite materials. The specific surface area values of the studied materials are investigated using nitrogen gas adsorption at 77 K while the spectroscopic gamma ray attenuation is used to determine the effective density of the different samples. Zinc oxide particles are dispersed on cupric oxide ribbons and cause nonlinear dependence of the specific surface area and density on the composition ratio due to the physical contact between particles, especially at the voids and the nodes of the fibrous ribbons network. 相似文献