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排序方式: 共有195条查询结果,搜索用时 46 毫秒
41.
42.
提出了一个测定微量钴 (Ⅱ )的极谱吸附波新体系。在pH 9.5的柠檬酸铵底液中 ,钴(Ⅲ ) NRS络合物在 - 0 .5 7V(vs .SCE)有一良好的吸附波 ,二阶导数波峰电流与钴浓度在 0 .0 1~1.2 μg·ml- 1范围内呈线性关系 ,检出限为 5ng·ml- 1。研究了极谱波性质和形成机理 ,应用于锌电解液中微量钴的分析 ,简便快速 ,结果准确 相似文献
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《Mendeleev Communications》2020,30(4):472-473
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45.
Analysis of the published data on the vapor pressure and degree of electrolytic dissociation of perchloric acid revealed that the molar fraction of nondissociated HClO4 is determined by the Raoult—Henry law in a wide range of acidimetric concentrations and temperatures. The degree of dissociation of perchloric acid was calculated from its thermodynamic activity. The results of calculations agree satisfactorily with the known spectroscopic data. 相似文献
46.
F Willig B Burfeindt K Schwarzburg T Hannappel W Storck 《Journal of Chemical Sciences》1997,109(6):415-428
Electron transfer over the reaction distance corresponding to three saturated bonds occurs within 70 fs from the excited singlet
state of anchored perylene chromophores to empty electronic levels in a sponge-type anatase TiO2 electrode. Injected electrons can be consumed in three different types of recombination processes at the interface with the
electrolytic contact. Electron transport through the electrode follows a potential gradient that is set-up in the dark, corresponding
to the difference between the Fermi levels of the two contact materials. It is dominated by multiple trapping and trap filling
processes. 相似文献
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提出了一种合成正丁醛的新方法———间接电解氧化法 .在陶瓷隔膜电解槽中 ,用Pb/PbO2 作阳极 ,石墨作阴极 ,将Mn2 + 氧化成Mn3 + ,然后用Mn3 + 作氧化剂对正丁醇进行氧化获得正丁醛 ,还原所得的Mn2 + 可循环利用 .电解的优选条件为 :C硫酸 =4 .0mol/L ,电流密度 80 0A/m2 ,CMn(II) =0 .5mol/L ,温度t=2 0℃ . 相似文献
49.
B. Liu P. S. Thomas R. P. Williams S. W. Donne 《Journal of Thermal Analysis and Calorimetry》2005,80(3):625-629
Summary Samples of electrolytic manganese dioxide (EMD) were chemically reduced using 2-propanol under reflux (82°C) for 1, 2, 3, 6 and 24 h intervals. XRD analysis showed that the -MnO2 structure was preserved although the lattice dimensions were observed to increase with increasing degree of reduction to accommodate the intercalation of protons. The exception was the 24 h reduced sample which contained two phases; -MnO2 and -MnOOH. Three regions of decomposition in the range of 50 to 1000°C were observed using thermogravimetric analysis coupled with mass spectrometry (TG-MS) and were accounted for as water removal below 390°C, reduction of MnO2 to Mn2O3 between 400 and 600°C, and Mn2O3 to Mn3O4 between 600 and 1000°C. Again the exception proved to be the 24 h reduced sample which was observed to decompose predominantly in one step between 400 and 600°C directly to Mn3O4. 相似文献
50.
E. Matykina R. Arrabal P. Skeldon G. E. Thompson 《Surface and interface analysis : SIA》2010,42(4):221-226
Plasma electrolytic oxidation (PEO) is a surface treatment technology enabling fabrication of adherent thick (50–150 µm) coatings on light metal alloys with significantly enhanced hardness, wear and corrosion resistance compared with other conventional treatments. The technology has the potential to play a significant role in the transport sector for replacement of steel with light‐weight materials of improved durability. A main limitation of PEO lies in its relatively high cost, associated with high energy consumption and low coating efficiency. The present work explores possible routes to improve the process efficiency. It is shown that a combination of conventional pre‐anodising with sequential PEO treatment reduces specific energy consumption up to five times because of an increase of the coating growth rate, up to 10 µm/min, compared with existing PEO processes. A further approach to improved coating efficiency involves PEO in electrolytes with suspended fine or nanoparticles, which results in the formation of thicker coatings in reduced time as a result of the incorporation of the particles from the electrolyte into the coating. Additionally, melting of the coating material during the micro‐arc discharge process leads to formation of stabilised high‐temperature phases, such as tetragonal and cubic zirconia, which provide significantly improved microhardness of the coating material and give a potential for thermal barrier applications. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献