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排序方式: 共有2518条查询结果,搜索用时 15 毫秒
61.
StudiesonColloidalPropertiesofMixedMetalHydroxide-ClayAqueousSuspensionNOUwan-guo;ZHANGChun-guang;SUNDe-jun;HANShu-huaandWANG... 相似文献
62.
Transition metal oxide doped lanthanum gallates, La0.9Sr0.1Ga0.8M0.2O3 (where M=Co, Mn, Cr, Fe, or V), are studied as mixed ionic-electronic conductors (MIECs) for electrode applications. The
electrochemical properties of these materials in air and in H2 are characterized using impedance spectroscopy, open cell voltage measurement, and gas permeation measurement. Three single
cells based on La0.9Sr0.1Ga0.8 Mg0.2O3 (LSGM) electrolyte (1.13 to 1.65 mm thick) but with different electrode materials are studied under identical conditions
to characterize the effectiveness of the lanthanum gallate-based MIECs for electrode applications. At 800 °C, a single cell
using La0.9Sr0.1- Ga0.8Co0.2O3 as the cathode and La0.9Sr0.1Ga0.8Mn0.2O3 as the anode shows a maximum power density of 88 mW/cm2, which is better than that of a cell using Pt as both electrodes (20 mW/cm2) and that of a cell using La0.6Sr0.4CoO3 (LSC) as the cathode and CeO2-Ni as the anode (61 mW/cm2) under identical conditions. The performance of LSGM-based fuel cells with MIEC electrodes may be further improved by reducing
the electrolyte thickness and by optimizing the microstructures of the electrodes through processing.
Received: 9 January 1998 / Accepted: 1 May 1998 相似文献
63.
Karen?Glenn Andrew?van?Bommel Subhash?C.?Bhattacharya Rama?M.?PalepuEmail author 《Colloid and polymer science》2005,283(8):845-853
The mixed micelles of sodium dodecyl sulphate (SDS) with Brij35 and Brij 97 were studied separately by fluorescence measurement using pyrene as fluorescent probe. In the range of 0–1.0 mole fraction (X) of added SDS to Brij solutions, the cmc value of the mixed micelles varies from 0.085 to 8 mmol with Brij 35 and 0.04 to 8 mmol with Brij 97. The aggregation number also changes. A measure of the stability of mixed micelles is also presented. The interaction parameter 12 and the chain–chain contribution parameter (B1) are extracted from the analysis of the results. This parameter B1 is related to the standard free energy change associated with the introduction of one ionic species into a nonionic micelle coupled with the release of one nonionic species from the micelle. The clouding behaviour of Brij 97 in the presence of SDS was investigated and the associated thermodynamic parameters of clouding were generated and discussed. 相似文献
64.
Alain H. Roux Daniel Hétu Gérald Perron Jacques E. Desnoyers 《Journal of solution chemistry》1984,13(1):1-25
Mixed micelles can be formed in water between various pairs of hydrophobic solutes such as surfactants, alcohols and hydrocarbons. These systems can often be studied through the thermodynamic functions of transfer of one of the solutes, usually kept near infinite dilution, from water to an aqueous solution of the other solute. When mixed micelles are formed, these functions change significantly, and often go through extrema, in the region where the binary system micellizes or undergoes some microphase transition.Three main effects are responsible for the observed trends: pair-wise interactions between both solutes in the monomeric form, a distribution of the reference solute between the aqueous and micellar phases and a shift in the monomer-micelle equilibrium in the vicinity of the reference solute. Simple equations can be derived for these three effects which can account for the sign and magnitude of the observed trends using parameters which are derived for the most part from the two binary systems. 相似文献
65.
66.
In this work we address the optimization of mixed conductivity in fluorite compounds based on zirconia. Phase relations of the new systems YbO1.5-NbO2.5-ZrO2, and CaO-NbO2.5-ZrO2 are presented. The limit of the cubic defect fluorite phase in YbO1.5-NbO2.5-ZrO2 closely resembles that of the system YO1.5-NbO2.5-ZrO2, whilst in CaO-NbO2.5-ZrO2 is narrow extending to include composition Ca0.255Nb0.15Zr0.595O1.82 at 1500°C. The influence of dopant ion size, charge and composition on ionic conduction is assessed and parallels are drawn with the systems YO1.5-NbO2.5-ZrO2 and YO1.5-TiO2-ZrO2. Comparison of these results with published data on the Ti containing systems CaO-TiO2-ZrO2, GdO1.5-TiO2-ZrO2 shows that the highest mixed conducting compositions can only be offered in the system YO1.5-TiO2-ZrO2 out of all the systems here studied. 相似文献
67.
Hideko Koshima Teruo Matsuura 《Journal of photochemistry and photobiology. A, Chemistry》1996,100(1-3):85-91
This paper deals with the solid state bimolecular photoreactions occurring at the interface between crystallites of two different organic compounds prepared as a polycrystalline mixture by melting-resolidification. The photoreactions include the photoaddition of NH compounds to aromatic and olefinic double bonds, hydrogen abstraction, condensation reaction via photoelectron transfer and [2+2] photoaddition. Particular attention is focused on the characterization of the polycrystalline mixture, the selectivity of the photoreactions in the solid state compared with those in the solution phase and the factors controlling the photoreactions. 相似文献
68.
本文研究了上文提出催化光度测定硒的有关机理。非离子表面活性剂(NSF)对硒催化S~(2-)还原亚甲基蓝(MB)退色产生胶束催化作用。首先,MB与NSF形成带阳电的混合胶束(NSF-MB)。在此,MB增溶于NSF胶束的栅状层和聚氧乙烯外壳,然后,〔S…Se°〕~(2-)被吸附于此混合胶束的界面。由于增溶和吸附的双重富集作用,使胶束界面反应物的浓度大大提高,从而促进了反应速率。反应速度增加的大小,决定于形成NSF-MB混合胶束的难易(这又决定于NSF的憎水基的结构)及〔S…S°〕~(2-)和〔S…Se°〕~(2-)在此混合胶束界面吸附能力的大小。 相似文献
69.
L. -M. Yuan R. -N. Fu S. -H. Gui X. -T. Xie R. -J. Dai X. -X. Chen Q. -H. Xu 《Chromatographia》1997,46(5-6):291-294
Summary The gas chromatographic separation of xylene isomers using special mixed stationary phases consisting of heptakis(2.3.6-tri-O-pentyl)-β-CD-AgNO3, heptakis (2.3.6-tri-O-pentyl)-β-CD-TINO3 or bentone-34-AgNO3 is investigated. The first two have positive synergistic effects for the separation of m, and p-xylene isomers, but negative
synergistic effects for the m, and oisomers. The separation effects depend on temperature, mixing ratio and how mixing is
accomplished. 相似文献
70.
神经网络法用于多元混酸同时测定 总被引:1,自引:0,他引:1
利用多层神经网络误差反向传播算法处理酸碱电位滴定数据,求得出多元混合酸各组分的浓度,优化了神经网络的结构和参数,测定了三组分有机酸混合样品,结果良好,平均相对偏差RSD≤4%。 相似文献