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31.
电感耦合等离子体原子发射光谱法测定钛酸钡纳米粉体中7种杂质元素 总被引:3,自引:0,他引:3
钛酸钡纳米粉体样品用盐酸溶解,在所得样品溶液中用电感耦合等离子体原子发射光谱法测定了以氧化物存在于样品中的7种杂质元素(包括镁、锶、钾、钠、铝、硅及铁),对测定的光谱条件进行了试验并优化达到上述各元素的测定上限为0.1%(质量分数).测得方法的检出限(3S/b)为(单位μg·L-1):2.0(铝),1.0(铁),20.0(钾),0.2(镁),4.0(钠),3.0(硅)及0.5(锶).应用此方法分析了两件实样,所得结果的相对标准偏差(n=6)小于等于2.0%,对其中4种杂质元素(镁、钾、钠和锶)同时用HG/T 3587-1999标准中的方法作分析校核,所得结果与此方法结果一致. 相似文献
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Melian-Cabrera I Kapteijn F Moulijn JA 《Chemical communications (Cambridge, England)》2005,(16):2178-2180
BEA zeolite has been simultaneously detemplated and Fe-exchanged by treating the parent zeolite with a Fenton's-type reagent (Fe3+-H2O2) at low temperature. This one-pot process simplifies and speeds up considerably the preparation route. The catalyst shows excellent performance on N2O decomposition compared to conventionally prepared Fe-BEA. 相似文献
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A. van de Riet H. Vonk Xu Xiaoding E. Otten A. Cybulski A. Stankiewicz R. Edvinsson J. A. Moulijn 《Reaction Kinetics and Catalysis Letters》1997,60(2):339-349
A series of Ni on alumina washcoated monoliths has been prepared and characterized. The selective liquid-phase hydrogenation
of benzaldehyde to benzyl alcohol in a Berty reactor has been used as a test reaction. 相似文献
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F.P.J.M. Kerkhof J.A. Moulijn A. Heeres 《Journal of Electron Spectroscopy and Related Phenomena》1978,14(6):453-466
XPS spectra of supported and unsupported tungsten oxides before and after use in the metathesis reaction of propene are reported. It is shown that the broad peaks, usually measured for supported materials, are due to line broadening caused by differential charging. A new sample preparation technique is described which leads to a considerable reduction of the line broadening. Both XPS and X-ray diffraction show that in fresh catalysts a well-defined phase Of WO3 is present. The reduction of the supported trioxide by propene to W20O58, as concluded from X-ray diffraction measurements, results in the formation of Wv - and/or WIV -species in used catalysts. For unsupported WO3 these lower valencies have been observed in the valence-band spectra. 相似文献
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The decomposition of N2O is strongly promoted by NO over steam-activated FeZSM-5. The promoting effect of NO is catalytic, and in addition to NO2, 2 is formed much more extensively at lower temperatures than in the absence of NO. The promotion effect only requires low NO concentrations in the feed, with no significant improvements at molar NO/N2O feed ratios higher than 0.25. No inhibition by NO was identified even at a molar NO/N2O feed ratio of 10, suggesting different sites for NO adsorption and oxygen deposition by N2O. The latter sites seem to be remote from each other. Transient experiments using in situ FT-IR/MS and Multitrack over FeZSM-5 further elucidate the mechanism of NO promotion. The release of oxygen from the catalyst surface during direct N2O decomposition is a rate-determining step due to the slow oxygen recombination, which is favored by high reaction temperatures. NO addition promotes this oxygen desorption, acting as an oxygen transfer agent, probably via NO2 species. Adsorbed NO may facilitate the migration of atomic oxygen to enhance their recombination. Less than 0.9% of Fe seems to participate in this promotion. A model is proposed to explain the phenomena observed in NO-assisted N2O decomposition, including NO2 decomposition. 相似文献
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This paper obtains solitons as well as other solutions to a few nonlinear evolution equations that appear in various areas of mathematical physics. The two analytical integrators that are applied to extract solutions are tan–cot method and functional variable approaches. The soliton solutions can be used in the further study of shallow water waves in (1+1) as well as (2+1) dimensions. 相似文献
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Melián-Cabrera I Kapteijn F Moulijn JA 《Chemical communications (Cambridge, England)》2005,(21):2744-2746
Detemplation of zeolite beta has been successfully achieved at low temperature by controlled oxidation of the template using H2O2 and catalyzed by traces of Fe3+. With this approach, unlike calcination, the pristine structure of the material is well preserved; no extra-framework aluminium is formed. 相似文献