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91.
Voltammetry at a rotating platinum electrode in concentrated electrolyte solutions containing HCl and LiCl is described for simultaneous determinations of iron(II) and iron(III) in a variety of materials. Applications of the method to some U.S. Geological Survey standard rocks, a Georgian clay, and an iron-containing multiple vitamin tablet are described. For materials which can be dissolved without altering the original iron(II)/ iron(III) ratio, this method enables the two valence states to be determined rapidly and simultaneously. The technique is precise (r.s.d. ≈ 2%) and relatively free from interference, and requires only a recording d.c. polarograph. 相似文献
92.
Banks CE Kruusma J Moore RR Tomcík P Peters J Davis J Komorsky-Lovrić S Compton RG 《Talanta》2005,65(2):423-429
Three different electroanalytical techniques for the detection of manganese in marine sediments are evaluated. The anodic stripping voltammetry of manganese at an in situ bismuth-film-modified boron-doped diamond electrode and cathodic stripping voltammetry at a carbon paste electrode are shown to lack the required sensitivity and reproducibility whereas cathodic stripping voltammetry at a bare boron-doped diamond electrode is shown to be reliable and selective with a limit of detection, from applying a 60 s accumulation period of 7.4 × 10−7 M and a sensitivity of 0.24 A M−1. The method was used to evaluate the manganese content of marine sediments taken from Šibenik, Croatia. 相似文献
93.
Y. X. Xia J. I. Friese D. A. Moore P. P. Bachelor L. Rao 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(1):79-86
The complexation of plutonium(IV) with sulfate at variable temperatures has been investigated by solvent extraction method.
A NaBrO3 solution was used as holding oxidant to maintain the plutonium(IV) oxidation state throughout the experiments. The distribution
ratio of Pu(IV) between the organic and aqueous phases was found to decrease as the concentrations of sulfate were increased.
Stability constants of the 1:1 and 1:2 Pu(IV)-HSO4
− complexes, dominant in the aqueous phase, were calculated from the effect of [HSO4
−] on the distribution ratio. The enthalpy and entropy of complexation were calculated from the stability constants at different
temperatures using the Van’t Hoff equation. 相似文献
94.
Evan R. Moore Andrew E. Bourne Todd J. Hoppe Philip J. Abode Steven R. Boone Gordon H. Purser 《国际化学动力学杂志》2004,36(10):554-564
The mechanism by which an excess of iron(II) ion reacts with aqueous chlorine dioxide to produce iron(III) ion and chloride ion has been determined. The reaction proceeds via the formation of chlorite ion, which in turn reacts with additional iron(II) to produce the observed products. The first step of the process, the reduction of chlorine dioxide to chlorite ion, is fast compared to the subsequent reduction of chlorite by iron(II). The overall stoichiometry is The rate is independent of pH over the range from 3.5 to 7.5, but the reaction is assisted by the presence of acetate ion. Thus the rate law is given by At an ionic strength of 2.0 M and at 25°C, ku = (3.9 ± 0.1) × 103 L mol?1 s?1 and kc = (6 ± 1) × 104 L mol?1 s?1. The formation constant for the acetatoiron(II) complex, Kf, at an ionic strength of 2.0 M and 25°C was found to be (4.8 ± 0.8) × 10?2 L mol?1. The activation parameters for the reaction were determined and compared to those for iron(II) ion reacting directly with chlorite ion. At 0.1 M ionic strength, the activation parameters for the two reactions were found to be identical within experimental error. The values of ΔH? and ΔS? are 64 ± 3 kJ mol?1 and + 40 ± 10 J K?1 mol?1 respectively. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 554–565, 2004 相似文献
95.
Crystal orientation-ordered ZnS nanowire bundles 总被引:1,自引:0,他引:1
We report a novel approach for growing aligned and orientation-ordered ZnS nanowires. Our method relies on a buffer layer of CdSe grown on a Si(111) substrate, on which ZnS nanowires are grown. The growth process of the nanowire bundles is presented. The technique demonstrated could be an effective pathway for growing patterned, aligned, size-controlled, and orientation-ordered ZnS nanowires. 相似文献
96.
97.
98.
H. Penttilä D. Gorelov V. -V. Elomaa T. Eronen U. Hager J. Hakala A. Jokinen A. Kankainen P. Karvonen I. D. Moore J. Parkkonen K. Peräjärvi I. Pohjalainen S. Rahaman S. Rinta-Antila J. Rissanen V. A. Rubchenya A. Saastamoinen V. Simutkin T. Sonoda C. Weber A. Voss J. Äystö 《The European Physical Journal A - Hadrons and Nuclei》2016,52(4):104
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100.