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131.
The structure of the semiconducting glassy As2Se3Hgx system was investigated in a composition range x = 0.005?0.12. An explanation of the anomalous behaviour of the macroscopic density is proposed, based on the analysis of radial electron density distribution curves. A formula is given which correlates quantitatively the magnitude of coordination spheres with the experimental macroscopic density. 相似文献
132.
Necessary and sufficient conditions for the existence of a complex structure in an 8-dimensional spin vector bundle over a
closed connected spin manifold of dimension 8 are given in terms of characteristic classes. The result completes the papers
by Heaps [H] and Thomas [T] on the same topic.
Received: 2 May 1997 相似文献
133.
Commuting Toeplitz operators with harmonic symbols 总被引:7,自引:0,他引:7
This paper shows that on the Bergman space, two Toeplitz operators with harmonic symbols commute only in the obvious cases. The main tool is a characterization of harmonic functions by a conformally invariant mean value property.The first author was partially supported by the National Science Foundation. 相似文献
134.
N. Aissaoui F. Haas R. M. Freeman C. Beck A. Morsad B. Djerroud R. Čaplar G. A. Monnehan A. Hachem M. Youlal 《Zeitschrift für Physik A Hadrons and Nuclei》1994,348(3):237-238
The 16 O+ 15 N reaction products have been studied by the γ-ray detection method in the CM energy range 15.5 to 36.1 MeV and by the kinematical coincidence method at energies ranging from E CM =20.6 to 33.5MeV. The γ-ray yield excitation function of the 16O 3? inelastic channel shows the existence of resonant structures. Two structures with ~ 1.6 MeV width are observed in the large angle elastic scattering excitation function, they are correlated with the resonances seen in the inelastic channel. Angular momentum assignments were made from the elastic backward angular distributions. 相似文献
135.
136.
Electrochemical Activity of Wedelolactone and Probing its Interaction with DNA Using Voltammetry at a Carbon Electrode
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Wedelolactone (WLA) is a polyphenolic coumestan derivative found in extracts of plants used in traditional medicine. Due to its cytostatic activity, WLA is one of natural compounds tested as potential anticancer drugs. In this work we for the first time studied electrochemical properties of WLA using cyclic (CV) and square‐wave (SWV) voltammetry at the basal‐plane pyrolytic graphite electrode. A reversible pair of peaks, corresponding to catechol/o‐benzoquinone redox system, was observed using CV around 0.275 V vs. Ag|AgCl|3 M KCl reference electrode. Measurements of SWV signal of WLA in the presence of single‐ or double‐stranded DNA suggested a weak interaction without evident preference for double‐stranded DNA. An indirect assay, employing electroactive DNA intercalator doxorubicin as competitor, confirmed absence of intercalative DNA binding of WLA. 相似文献
137.
138.
Jiří Čmelík Zdeňka Nainarová Petr Ryšánek 《International journal of environmental analytical chemistry》2015,95(12):1090-1098
The developed and tested method is based on the acid volatile sulphur (AVS) releasing from a sample of sediment by acidification with hydrochloric acid and sequential absorption of released hydrogen sulphide into the absorption solution of sodium hydroxide. Total sulphur absorbed in the absorption solution is subsequently determined by inductively coupled plasma optical emission spectrometry (ICP-OES) technique. The method was tested using both model and real samples of the river sediment. Obtained results were compared with the results of iodometric determination as the method routinely used for the AVS determination. In case of using ICP-OES with purge and trap, there is no spectral interference of calcium; therefore for the determination of sulphur, it is possible to use atomic emission line of sulphur S I 180.7 nm. The tested method provides the results comparable with the iodometric method within the range of tested concentrations. The detection limit (LOD) of this method is 0.09 mg· S2? ? L?1 in the absorption solution which corresponds to 0.23 mg S2?·kg?1 in a sediment. Value of LOD is comparable with the iodometric determination. 相似文献
139.
Čížková M Kolivoška V Císařová I Šaman D Pospíšil L Teplý F 《Organic & biomolecular chemistry》2011,9(2):450-462
A modular approach to the construction of monocationic quaternary N-heteroaromatic frameworks was developed capitalizing on a direct pyridine-type nitrogen quaternization followed by metal-catalyzed [2+2+2] cycloaddition with gaseous acetylene. The flexibility of the route is demonstrated on 12 diverse scaffolds based on pyridinium, quinolinium, thiazolium, benzothiazolium, imidazolium, and pyrimidinium. Electrochemical study revealed a quinolinium redox system with two electrochemically distinct forms that are interconverted by a homogeneous chemical reaction triggered by fast electron transfers (reduction at -0.7 V and oxidation at -0.05 V). 相似文献
140.
Vladan Čelebonović 《高压研究》2013,33(1-6):693-695
Abstract Using the mass and radius of Uranus, as determined by Voyager, and a particular semiclassical theory of dense matter, a model of its interior has been developed. Details of the model, the underlying theory and possible sources of discrepancies with recent work on this topic are briefly presented. 相似文献