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排序方式: 共有239条查询结果,搜索用时 234 毫秒
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P. Palade G. Principi T. Spataru P. Blaha K. Schwarz V. Kuncser S. Lo Russo S. Dal Toé V. A. Yartys 《Journal of Radioanalytical and Nuclear Chemistry》2005,266(3):553-556
Summary LaNiSn and NdNiSn compounds and their deuterides have been studied by variable temperature 119Sn M?ssbauer spectroscopy. The hyperfine parameters obtained experimentally are in good agreement with those derived from
first principle calculations. The enlargement of quadrupole splitting observed for LaNiSn after deuteration confirms the lower
symmetry of electron density around tin atoms indicated by the calculation of partial Sn-p density of states (DOS). Magnetic
ordering is observed at low temperature in deuterided NdNiSn. 相似文献
3.
Sorin Staicu Ilie G Dinulescu Filip Chiraleu Margaret Avram 《Journal of organometallic chemistry》1976,113(4):C69-C72
Coupling of diarylacetylenes with alkenes in the presence of dichlorobis(benzonitrile)palladium gives chloro(syn-1-chloro-anti-1-aryl-syn-3-alkyl)-π-allylpalladium complexes. 相似文献
4.
The simultaneous isolation and determination of mitoxantrone (Novantrone) and its two known metabolites (the mono- and dicarboxylic metabolites) were carried out using a high-performance liquid chromatographic (HPLC) system equipped with an automatic pre-column-switching system that permits drug analysis by direct injection of biological samples. Plasma or urine samples were injected directly on to an enrichment pre-column flushed with methanol-water (5:95, v/v) as the mobile phase. The maximum amount of endogenous water-soluble components was removed from biological samples within 9 min. Drugs specifically adsorbed on the pre-column were back-flushed on to an analytical column (Nucleosil C18, 250 X 4.6 mm I.D.) with 1.6 M ammonium formate buffer (pH 4.0) (2.5% formic acid) containing 20% acetonitrile. Detection was effected at 655 nm. Chromatographic analysis was performed within 12 min. The detection limit of the method was about 4 ng/ml for urine and 10 ng/ml for plasma samples. The precision ranged from 3 to 11% depending on the amount of compound studied. This technique was applied to the monitoring of mitoxantrone in plasma and to the quantification of the unchanged compound and its two metabolites in urine from patients receiving 14 mg/m2 of mitoxantrone by intravenous infusion for 10 min. 相似文献
5.
Thermostable heterocyclic polymers containing benzimidazole and imide rings, as well as flexible ester groups, have been synthesized by solution polycondensation of diaminobenzimidazoles with dianhydrides incorporating preformed ester linkages. The thermal stability and the electrical insulating properties of these products are discussed and compared with related heterocyclic polymers. 相似文献
6.
Bogdan Tutunaru Adriana Samide Catalin Negrila 《Journal of Thermal Analysis and Calorimetry》2013,111(2):1149-1154
The influence of different ions NO3 ? and SO4 2? on the carbon steel corrosion in ammonium chloride was investigated using mass loss measurements and potentiodynamic polarization. Corrosion products were analyzed using X-ray photoelectron spectroscopy (XPS) and simultaneous thermal and differential scanning calorimetry (TG/DSC). XPS analysis shows that the main product of corrosion is a non-stoichiometric Fe3+ oxyhydroxide, consisting of a mixture of FeO(OH) and FeO(OH) containing inclusions of these anions, species such as Fe3+O(OH,Cl?); Fe3+O(OH,SO4 2?); and Fe3+O(OH,NO3 ?). TG/DSC confirms the decomposition of the rusty products formed by chemical corrosion, compounds like Fe3+ oxyhydroxides, with β-FeOOH as the major phase, crystal structure of which may contain Cl?, NO3 ?, and SO4 2?—e.g., akaganeite [Fe3+O(OH,A)]. 相似文献
7.
This work is focused on the compressive behavior in the elastic region of a composite material made out of stalk-based maize fiber and unsaturated polyester resin polymer as matrix with methyl ethyl ketone peroxide as a catalyst and Cobalt Octoate as a promoter [1]. Deformation and fracture behavior are investigated by using Extended Finite Element Method (XFEM). XFEM enables the accurate approximation of solutions with jumps, discontinuities or general high gradients across interfaces between the fibers and the matrix [2], [3]. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
8.
In the last paper, the geometry of the Sz.-Nagy-Foia
model for contraction operators on Hilbert spaces was used to advantage in several problems of multivariate analysis. The lifting of intertwining operators, one of the basic results from the Sz.-Nagy-Foia
theory, is now recognized as the most adequate operatorial form of the deep classical results of the extrapolation theory. The labeling of the exact intertwining dilations given by [1]Acta Sci. Math. (Szeged) 40 9–32] and the recursive methods used there open a broad perspective for using the Sz.-Nagy-Foia
model in multivariate filtering theory. In this paper, using the notion of correlated action (see [5 and 6] Rev. Roumaine Math. Pures Appl. 23, No. 9 1393–1423]) as a time domain, a linear filtering problem is formulated and its solution in terms of the coefficients of the analytic function which factorizes the spectral distribution of the known data and the coefficients of an analytic function which describes the cross correlations is given. In some special cases it is shown that the filter coefficients can be determined using recursive methods from the intertwining dilation theory, of the autocorrelation function of the known data and an intertwining operator, interpreted as the initial estimator given by the prior statistics. 相似文献
9.
We present a theoretical analysis and first-principles calculation of the radiative lifetime of excitons in semiconducting carbon nanotubes. An intrinsic lifetime of the order of 10 ps is computed for the lowest optically active bright excitons. The intrinsic lifetime is, however, a rapid increasing function of the exciton momentum. Moreover, the electronic structure of the nanotubes dictates the existence of dark excitons near in energy to each bright exciton. Both effects strongly influence measured lifetime. Assuming a thermal occupation of bright and dark exciton bands, we find an effective lifetime of the order of 10 ns at room temperature, in good accord with recent experiments. 相似文献
10.
An inequality is established involving colengths of the tightclosure of ideals of systems of parameters in local rings withsome mild conditions. As an application, a proof is given ofa result due to Goto and Nakamura (first conjectured by Watanabeand Yoshida), which states that the HilbertSamuel multiplicityof a parameter ideal is greater than or equal to the colengthof the tight closure of the ideal. The result is also furtherrefined. 2000 Mathematics Subject Classification 13D40, 13A35,13H15. 相似文献