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121.
The separation of silver from a uranium matrix has been carried out using Cyanex-471X (triisobutylphosphine sulphide) in xylene. The effects of various parameters such as the Cyanex-471X concentration, the nitric acid molarity, the contact time and the nitrate ion concentration on the extraction of silver have been studied. The silver metal ion species extracted into the organic phase was found to be Ag(NO3)·2S (where S is Cyanex-471X). The stripping of silver into an aqueous medium was carried out with 5% NaHSO3, followed by its determination using ICP-AES. 相似文献
122.
123.
S. Hermann P. Neuschul V. Lucas L. Bracaloni F. Berger M. Kochmann H. Kunz A. Lévêque J. Moulin C. van Zijp R. Kleinert K. Bambach T. H. Rider D. Payer K. Peták H. Kaiser H. Will Ch. F. Poe C. H. Hampshire G. R. Page W. Karaffa-Korbutt L. Rosenthaler L. D. Korosstischewskaja Marguerite van Hauwert H. Leonhardt R. Klockmann R. P. Jacquemain H. Mistroff G. F. Reddish D. Bartos J. Buchgraber E. Klarmann V. A. Shternov A. Mossini M. G. Vergez 《Analytical and bioanalytical chemistry》1938,114(9-10):368-375
124.
H. J. M. Bowen E. Page I. Valente R. J. Wade 《Journal of Radioanalytical and Nuclear Chemistry》1979,48(1-2):9-16
Radio-tracer experiments have shown that antimony, mercury and zinc interact to form complexes with humic and/or fulvic acids,
whose molar masses can be estimated by gel chromatography. Sb(III) and (V) humates are stable in the pH range 7–11, but are
largely dissociated below pH 4; humic acid does not reduce Sb(V) to Sb(III) in solution. Mercury forms a strong complex with
humic+fulvic acids. Zinc forms complexes with both humic acids and glycine, and the humic acid complex has similar elution
behaviour on dextran gel to a fraction from river water equilibrated with65Zn. At least one other form of zinc, in addition to Zn2+, occurs in this river. 相似文献
125.
An analysis of the contact mechanics and the forces of interaction in lateral force microscopy measurements is presented. This analysis allows for a new method of interpretation of the frictional forces, the lateral contact stiffness, and the contact shear strength. The technique was developed for the interpretation of frictional data obtained with colloidal probes, although results are presented which illustrate its ability to interpret measurements recorded with both colloidal probes and standard atomic force microscopy tips. The technique is found to compensate for the variations in the contact geometry, giving repeatable results for probes of different sizes. A critical review of other techniques which have been employed to interpret the frictional force in lateral force microscopy is also presented. Copyright 2000 Academic Press. 相似文献
126.
A procedure for the direct polarographic determination of aluminium is described, with particular reference to zinc-base die-casting alloys. Interfering elements are removed by electrolysis of a solution of the alloy in a mercury-cathode cell. The solution is polarographed at a carefully controlled pH in a supporting electrolyte of magnesium chloride and sodium sulfate of appropriate concentration. The precision and accuracy of the method are shown to be satisfactory by the analysis of standard samples from three different laboratories. 相似文献
127.
Equilibrium configurations of self-gravitating massless thermal radiation inside spherical boxes of radiusR in asymptotically anti-de Sitter space (A = -3/b
2) are constructed numerically for a range of central densities. For each box radius considered (R/b = 0, 1/2, 1, 2, 4, ), there is a unique configuration with maximal total mass and entropy, and another (at a lower central density) with maximum asymptotic red-shifted temperature. With the box removed toR=, the maximum total mass and entropy of self-gravitating thermal radiation areM
max 0.4598b0.7964(–A)–1/2 andS
max1.3560a
1/4
b
3/2 3.0910a
1/4(–A)–3/4, and the maximum red-shifted temperature is 相似文献
128.
129.
P. MORLIÉRE M. BAZIN L. DUBERTRET R. SANTUS T. SA E. MELO G. HÜPPE J. HAIGLE P. FORLOT A. BERNARD 《Photochemistry and photobiology》1991,53(1):13-19
5-Geranoxypsoralen, commonly called bergamottin, a major furocoumarin contained in bergamot oil, is reported in vitro as a highly photoreactive psoralen. In ethanol, it exhibits quite a high triplet state quantum yield (approximately 0.37). The triplet state is involved in subsequent photochemistry which depends on the initial concentration and on the presence of oxygen. In contrast to most psoralens, absorption and fluorescence data suggest that 5-geranoxypsoralen does not interact with DNA in the dark. No UVA-induced interstrand cross-links in DNA were shown. 相似文献
130.