共查询到20条相似文献,搜索用时 8 毫秒
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Woo-Hee Kim Hyungjun Kim Han-Bo-Ram Lee 《Journal of Coatings Technology and Research》2017,14(1):177-183
Thin film optics, based on light interference characteristics, are attracting increasing interest because of their ability to enable a functional color coating for various applications in optical, electronic, and solar industries. Here, we report on the dependence of coloring characteristics on single-layer TiO2 thicknesses and alternating TiO2/Al2O3 multilayer structures prepared by atomic layer deposition (ALD) at a low growth temperature. The ALD TiO2 and Al2O3 thin films were studied at a low growth temperature of 80°C. Then, the coloring features in the single-layer TiO2 and alternating TiO2/Al2O3 multilayers using both the ALD processes were experimentally examined on a TiN/cut stainless steel sheet. The Essential Macleod software was used to estimate and compare the color coating results. The simulation results revealed that five different colors of the single TiO2 layers were shown experimentally, depending on the film thickness. For the purpose of highly uniform pink color coating, the film structures of TiO2/Al2O3 multilayers were designed in advance. It was experimentally demonstrated that the evaluated colors corresponded well with the simulated color spectrum results, exhibiting a uniform pink color with wide incident angles ranging from 0° to 75°. This article advances practical applications requiring highly uniform color coatings of surfaces in a variety of optical coating areas with complex topographical structures. 相似文献
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Jeong Gil Seo Min Hye Youn Kyung Min Cho Sunyoung Park Sang Hee Lee Joohyung Lee In Kyu Song 《Korean Journal of Chemical Engineering》2008,25(1):41-45
An Al2O3-ZrO2 xerogel (AZ-SG) was prepared by a sol-gel method for use as a support for a nickel catalyst. The Ni/AZ-SG catalyst was then
prepared by an impregnation method, and was applied to hydrogen production by steam reforming of LNG. A nickel catalyst supported
on commercial alumina (A-C) was also prepared (Ni/A-C) for comparison. The hydroxyl-rich surface of the AZ-SG support increased
the dispersion of nickel species on the support during the calcination step. The formation of a surface nickel aluminate-like
phase in the Ni/AZ-SG catalyst greatly enhanced the reducibility of the Ni/AZ-SG catalyst. The ZrO2 in the AZ-SG support increased the adsorption of steam onto the support and the subsequent spillover of steam from the support
to the active nickel sites in the Ni/AZ-SG catalyst. Both the high surface area and the well-developed mesoporosity of the
Ni/AZ-SG catalyst improved the gasification of adsorbed surface hydrocarbons in the reaction. In the steam reforming of LNG,
the Ni/AZ-SG catalyst showed a better catalytic performance than the Ni/A-C catalyst. Moreover, the Ni/AZ-SG catalyst showed
strong resistance toward catalyst deactivation. 相似文献
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V. A. Sokolov T. Ya. Malysheva M. D. Gasparyan 《Refractories and Industrial Ceramics》2008,49(2):146-148
Details are given of the synthesis and testing of flux-cast refractory materials in the alumina-rich region of the Al2O3-MgO-B2O3 system; XRD and petrography indicate that the main structure-forming phases are corundum and magnesian spinel. In subordinate
amounts there are the boroaluminate 9Al2O3·2B2O3 and the previously unknown compound 4Al2O3·MgO·2B2O3, whose composition has been established by microprobe analysis. Corrosion tests showed that three-component systems containing
magnesium and boron oxides at levels of 5–10% do not increase the corrosion resistance of refractories in molten sodium-calcium-silicate
glass and electrovacuum borosilicate glass.
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Translated from Novye Ogneupory, No. 3, pp. 161–163, March, 2008. 相似文献
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Kamila Michalska Paweł Kowalik Wiesław Próchniak Tadeusz Borowiecki 《Catalysis Letters》2018,148(3):972-978
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S. A. Nemov A. V. Marchenko P. P. Seregin E. A. Tomil’tsev 《Glass Physics and Chemistry》2007,33(6):658-660
Triply and doubly charged states of europium are revealed by 151Eu Mössbauer spectroscopy in the structure of glasses of the composition (mol %) 19.5Al2O3, 31.5SiO2, 26.5MnO, and 22.5Eu2O3. The isomer shifts in the Mössbauer spectra of Eu3+ and Eu2+ ions in the structure of glasses differ from the isomer shifts in the spectra of the Eu2O3 and EuO compounds. This difference is explained by the fact that the electron density at 151Eu nuclei is affected by the manganese and aluminum atoms, which are not bound directly to the europium atoms. The broadening of the spectra of the Eu2+ ions in glasses is caused by the nonuniform isomer shift. 相似文献
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Jung-Hyun Park Eunpyo Hong Sang Hee An Dong-Hee Lim Chae-Ho Shin 《Korean Journal of Chemical Engineering》2017,34(10):2610-2618
Ni(x)/Al2O3 (x=wt%) catalysts with Ni loadings of 5–25 wt% were prepared via a wet impregnation method on an γ-Al2O3 support and subsequently applied in the reductive amination of ethanol to ethylamines. Among the various catalysts prepared, Ni(10)/Al2O3 exhibited the highest metal dispersion and the smallest Ni particle size, resulting in the highest catalytic performance. To reveal the effects of reaction parameters, a reductive amination process was performed by varying the reaction temperature (T), weight hourly space velocity (WHSV), and NH3 and H2 partial pressures in the reactions. In addition, on/off experiments for NH3 and H2 were also carried out. In the absence of NH3 in the reactant stream, the ethanol conversion and selectivities towards the different ethylamine products were significantly reduced, while the selectivity to ethylene was dominant due to the dehydration of ethanol. In contrast, in the absence of H2, the selectivity to acetonitrile significantly increased due to dehydrogenation of the imine intermediate. Although a small amount of catalyst deactivation was observed in the conversion of ethanol up to 10 h on stream due to the formation of nickel nitride, the Ni(10)/Al2O3 catalyst exhibited stable catalytic performance over 90 h under the optimized reaction conditions (i.e., T=190 °C, WHSV=0.9 h?1, and EtOH/NH3/H2 molar ratio=1/1/6). 相似文献
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Synthetic spinels of the system MgO-Cr2O3-Al2O3-Fe2O3 are considered and the desirability of organizing their production for the refractory industry is demonstrated.
Translated from Novye Ogneupory, No. 6, pp. 32–35, June 2008. 相似文献
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S. F. Tikhov Yu. N. Bespalko V. A. Sadykov A. N. Salanov S. I. Reshetnikov 《Combustion, Explosion, and Shock Waves》2016,52(5):535-543
The activity of plates of CuO/Al2O3/FeAlO/FeAl structured cermet catalysts is compared by varying their alumina content. The catalysts were prepared by impregnation of cermet supports obtained by mechanochemical activation of powder mixtures of an alumina precursor [20–50% (wt.)], iron, and aluminum, followed by hydrothermal treatment and calcination. It is shown that increasing the content of the alumina precursor (product of thermal activation of gibbsite) increases the specific surface area of the support and the mesopore and macropore volumes and reduces its mechanical strength. The content of the active component (CuO) also increases, resulting in an increase in the specific activity of catalyst despite a reduction in the effectiveness of using the active component. The activity of catalysts with a moderate concentration of alumina is sufficient to initiate methane oxidation. 相似文献
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Cu/ZnO/Al2O3 catalysts with Cu/Zn/Al ratios of 6/3/1 were precipitated and aged by conventional and microwave heating methods and tested in the slurry phase reactor for methanol synthesis. The effect of technological condition of precipitation and aging process under microwave irradiation on the catalytic performance was investigated to optimize the preparing condition of Cu/ZnO/Al2O3 catalyst. The results showed that the microwave irradiation during precipitation process could improve the activity of the catalyst, but had little effect on the stability. While the microwave irradiation during aging process has a great benefit to both the activity and stability of the catalyst, the catalyst aged at 80°C for 1 h under microwave irradiation possessed higher methanol space time yield (STY) and more stable catalytic activity. The activity and stability of the catalyst was further enhanced when microwave irradiation was used in both precipitation and aging processes; the optimized condition for the catalyst precursor preparation was precipitation at 60°C and aging at 80°C under microwave irradiation. 相似文献
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Powder precursors have been prepared by means of the sol-gel technique and codeposition, and nanoceramics in the ZrO2-Al2O3-rare-earth (RE) oxide system (RE = Ce, Sc, or Y) based on them have been obtained. Physicochemical properties of the resulting ceramic composites have been investigated. The energy model for oxygen-ionic transport processes in a solid solution based on ZrO2, which relies on computer simulation procedure, has been proposed, and the structural, strength, and electrophysical characteristics of the solid solution have been calculated. The obtained materials are promising as high-melting electrochemical sensors in molten oxides. 相似文献
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Analysis of the formation of Al<Subscript>2</Subscript>O<Subscript>3</Subscript> + Fe nanocomposites
O. Yu. Goncharov O. V. Karban’ O. M. Nemtsova I. A. Il’in 《Glass Physics and Chemistry》2009,35(2):210-218
The formation of Al2O3 + Fe nanocomposites (in the range 0–20 wt % Fe) in the course of three sequential processes, such as dispersion, compaction, and sintering at a temperature of 1573 K, is investigated. It is revealed that the sintering is accompanied by the formation of the spinel phase at interfaces. It is demonstrated that the composition of the sintered samples corresponds to an equilibrium composition at a temperature of approximately 1073 K and that the spinel phase serves as a barrier layer preventing oxidation of iron 相似文献
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The phase composition and structure of fusion-cast refractories composed of 57.0 – 84.2% Cr2O3, 4.3 – 36.1% MgO, 2.0 – 9.7% Al2O3, and 2.4 – 6.9% SiO2 have been studied by petrographic and x-ray spectral microprobe analysis methods. Refractories high in MgO with modulus M = (Cr2O3 +Al2O3)/MgO = 1.64 – 3.1 are shown to consist of spinel phase Mg(Cr, Al)2O4 and silicate glass. Refractory materials (80.8 – 84.2% Cr2O3, 4.3 – 4.7% MgO, 2.0 – 9.7% Al2O3, and 2.7 – 6.9% SiO2 with M = 18.7 – 20.2) are three-phase systems composed of spinel, escolaite, and glass phase. These materials, owing to their high corrosion resistance, have promising potentiality for practical applications.__________Translated from Novye Ogneupory, No. 12, pp. 69 – 74, December, 2004. 相似文献
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Huimei Yu Xiaoxing Wang Zhu Shu Mamoru Fujii Chunshan Song 《Frontiers of Chemical Science and Engineering》2018,12(1):83-93
A series of Al2O3 and CeO2 modified MgO sorbents was prepared and studied for CO2 sorption at moderate temperatures. The CO2 sorption capacity of MgO was enhanced with the addition of either Al2O3 or CeO2. Over Al2O3-MgO sorbents, the best capacity of 24.6 mg- CO2/g-sorbent was attained at 100 °C, which was 61% higher than that of MgO (15.3 mg-CO2/g-sorbent). The highest capacity of 35.3 mg-CO2/g-sorbent was obtained over the CeO2-MgO sorbents at the optimal temperature of 200 °C. Combining with the characterization results, we conclude that the promotion effect on CO2 sorption with the addition of Al2O3 and CeO2 can be attributed to the increased surface area with reduced MgO crystallite size. Moreover, the addition of CeO2 increased the basicity of MgO phase, resulting in more increase in the CO2 capacity than Al2O3 promoter. Both the Al2O3-MgO and CeO2-MgO sorbents exhibited better cyclic stability than MgO over the course of fifteen CO2 sorption-desorption cycles. Compared to Al2O3, CeO2 is more effective for promoting the CO2 capacity of MgO. To enhance the CO2 capacity of MgO sorbent, increasing the basicity is more effective than the increase in the surface area. 相似文献
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Hakbeum Lee Won-Il Kim Kwang-Deog Jung Hyoung Lim Koh 《Korean Journal of Chemical Engineering》2017,34(5):1337-1345
We investigated the effects of different Cu weight ratio on θ or γ-Al2O3 which were impregnated with platinum in terms of catalytic activity for propane dehydrogenation and physicochemical properties. 1.5 wt% Pt, 0-10 wt% Cu catalyst supported on θ-Al2O3 or γ-Al2O3 was prepared by incipient wetness co-impregnation. Enhanced Pt dispersion by increasing Cu contents in γ-Al2O3 supported catalyst was confirmed via XRD and XPS. Pt and CuO was separated in Pt-Cu/θ-Al2O3, but Pt-Cu alloy was identified after reduction treatment. Also, adding Cu in Pt/Al2O3 makes catalyst’s acidity lower and this property led to increased propylene yield in propane dehydrogenation. However, Pt3Cu was not good for yield of PDH, which was confirmed in Pt-10Cu/θ-Al2O3 through XRD. 相似文献
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I. R. Il’yasov M. V. Nazarov A. I. Laskin A. A. Lamberov A. Sh. Bikmurzin V. M. Shatilov I. F. Nazmieva 《Catalysis in Industry》2011,3(1):96-101
The influence of the structural and electronic characteristics of nonpromoted and cobalt-promoted Pd catalysts on their adsorption
and catalytic properties is studied. It is shown that the conversion of vinylacetylene depends on the dispersion of palladium
for both types of catalysts synthesized from acetate and acetylacetonate complexes. The palladium acetylacetonate catalysts
have a higher palladium dispersion than the samples obtained from acetate complex solutions, thus leading to a higher conversion
of vinylacetylene. It is established that the selectivity of vinylacetylene conversion into 1,3-butadiene on palladium acetate
and acetylacetonate catalysts depends on the state of the 3d orbitals of surface Pd atoms. The palladium acetate catalysts are characterized by a higher electron density on the 3d orbital in comparison with the acetylacetonate samples, thus producing higher selectivities of vinylacetylene conversion
into 1,3-butadiene. The introduction of cobalt into Pd/δ-Al2O3 catalyst synthesized from acetylacetonate complex leads to the formation of bimetallic Pd-Co particles, in which Pd atoms
have higher electron density than those in the nonpromoted Pd/δ-Al2O3 catalyst, due probably to the donation of electron density from promoter atoms, with a resulting decline in the adsorption
ability of bimetallic particles with regard to 1,3-butadiene and hydrogen. As a consequence, the selectivity of vinylacetylene
conversion into 1,3-butadiene increases. Requirements for the size, dispersion, and electronic characteristics of the active
component in the catalysts for the selective hydrogenation of vinylacetylene are formulated, and two techniques for their
synthesis are proposed. 相似文献
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C. Sepulveda R. Garcia N. Escalona D. Laurenti L. Massin M. Vrinat 《Catalysis Letters》2011,141(7):987-995
Abstract
Rhenium sulfide based catalysts were prepared by the incipient wetness impregnation method over alumina and silica supports and evaluated for 4,6-dimethyldibenzothiophene hydrodesulfurization in a high-pressure stirred-tank reactor. The catalyst prepared over silica was about six times more active for hydrodesulfurization than the corresponding catalyst prepared over alumina and a NiMo/Al2O3 industrial reference catalyst. This surprising and positive SiO2 support effect was explained by a metallic character of the supported sulfide, which was demonstrated using a kinetic approach of competitive hydrogenations and by XPS characterization. 相似文献19.
Kang Shanjiao Dou Tao Li Qiang Duan Aijun Zheng Yanying Pan Huifang 《Journal of Porous Materials》2008,15(2):159-162
This paper presents the direct synthesis of super-low SiO2/Al2O3 ratio zeolite beta molecular sieve through a novel route, by which some of aluminium species are added during crystaling
process. The IR results show that with the increase of aluminium content in the framework, the frequency of the band in the
range of framework vibration (1060–1090 cm−1) shifts to the lower wave-number; the BET surface-area decreases and the basicity of zeolite becomes stronger. In a second
step, new adsorbents were obtained by solid-state ion exchanging zeolite beta with Cu(I), Ag(I) cations. The deep-desulfurization
(sulfur levels of <1 ppmw) tests were performed using fixed-bed adsorption technique, the sulfur content of the treated and
untreated gasoline was analyzed by microcoulometry. The experimental results show that the desulfurization performance of
sorbents decreases in order: Cu(I)beta > Ag(I)beta > Na-beta. The best sorbent, Cu(I)beta, has breakthrough adsorption capacities
of 0.236 mmolS/g of sorbent for model gasoline. 相似文献
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An investigation on viscosity was conducted 2 weeks after the Al2O3-water nanofluids having dispersants were prepared at the volume concentration of 1-5%. The shear stress was observed with
a non-Newtonian behavior. On further ultrasonic agitation treatment, the nanofluids resumed as a Newtonian fluids. The relative
viscosity increases as the volume concentrations increases. At 5% volume concentration, an increment was about 60% in the
re-ultrasonication nanofluids in comparison with the base fluid. The microstructure analysis indicates that a higher nanoparticle
aggregation had been observed in the nanofluids before re-ultrasonication. 相似文献