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51.
H. Th. Schneider B. P. Lisboa und H. Breuer 《Fresenius' Journal of Analytical Chemistry》1976,279(2):161-162
Ohne Zusammenfassung
Identification of hormone metabolites in tissue by radio gas chromatography相似文献
52.
J. Henrique Teles Johann-Peter Melder Klaus Ebel Regina Schneider Eugen Gehrer Wolfgang Harder Stefan Brode Dieter Enders Klaus Breuer Gerhard Raabe 《Helvetica chimica acta》1996,79(1):61-83
Stable carbenes derived from thiazole, 1H-imidazole, and 4H-1,2,4-triazole are efficient catalysts for benzointype condensations of formaldehyde. Catalysts derived from N-substituted thiazolium salts trimerize formaldehyde to dihydroxyacetone ( II ). Catalysts based on 1,4-disubstituted 4H-1,2,4-triazol-1-ium salts give glycolaldehyde ( I ) as the main product and no II , whereas N,N′-disubstituted 1H-imidazol-3-ium salts yield mixtures of both products. The isolation of several intermediates in the catalytic cycle provide a better insight into the reaction mechanism. 相似文献
53.
M. Gastel U. Breuer H. Holzbrecher J. S. Becker H. -J. Dietze M. Kubon H. Wagner 《Fresenius' Journal of Analytical Chemistry》1995,353(3-4):478-482
The determination of elemental distributions in thin film solar cells based on amorphous silicon using electron beam SNMS is possible by quantifying the measured ion intensities. The relative sensitivity factors (RSFs) for all elements measured have to be known. The RSFs have been determined experimentally using implantation and bulk standards with known concentrations of the interesting elements. The measured RSFs have been compared with calculated RSFs. The model used for the calculation of the RSFs takes into account the probability for electron impact ionization and the dwell time of the neutrals inside the postionization region. The comparison between measured and calculated RSF shows, that this model is capable to explain the RSFs for most elements. Differences between calculated and measured values can be explained by the formation of hydride and fluoride molecules (in case of H and F) and influences of the angular distribution of the sputtered neutrals in case of Al. The experimentally determined RSFs have been used for a quantification of depth profiles of the i-, buffer-, p- and front contact layers of a-Si solar cells. 相似文献
54.
Angular distributions have been measured for 3He elastic scattering from 36, 38, 40Ar at 26.5 MeV and from 36Ar and 40Ca at energies between 24.5 and 28 MeV. This scattering clearly shows features of “anomalous” backward-angle scattering, which is discussed in the systematics of 3He scattering from heavier target nuclei. The data for “anomalous” scattering can be described by optical potentials which show features significantly different from those of “normal” scattering. These features are smaller radius parameters for the real optical potential and a strongly reduced volume integral for the imaginary potential. 相似文献
55.
The new type of phosphoniminoxy free radicals was generated electrochemically or by chemical oxidation of oximes. It was established the strong difference of ESR parameters for isomeric Z and E forms of the radicals. The spin distribution and its correlation with electronic and spatial characteristics of molecules as well as with intramolecular interactions are discussed. 相似文献
56.
57.
High-spin states in156Er have been populated using the (α, 8n) and (16O, 4n) reactions. In the ground state band a strong backbending effect was observed atI π=12+. Four states of a secondK=0 band with spins 9, 11, 13 and 15 were found. This second band depopulates completely into the 8+ and 10+ members of the ground state band. This is explained by the fact that the upper states of this second band are yrast states and that this band crosses the (gsb)-line atI ?11. 相似文献
58.
The magnetical rotation of the plane of polarisation and the ellipticity of the reflected and transmitted light through magnetically saturated, evaporated layers of iron, cobalt and nickel (30 to 100 mμ) are dependent one another according to the phenomenological theory of W.Voigt. The four measured magnetooptical angles are however independent each other. By comparison of other physical properties, except the magnetooptical ones, (f. e. magnetical saturation, optical absorption) measured respectively with transmitted and with reflected light, we try to prove, that the layers are homogenous at least near the glass-side. The linear increase of Faraday-rotation and optical absorption with the thickness of the layer supports this assumption. Then the independence can only be explaned by a magnetooptical term in the second equation of Maxwell also (precession of spin). The knowledge of the optical constants ist necessary for the comparison of magnetooptical ones. They are find out by measurements of intensity only, using the transmitted light and the reflected light at both sides of the layer. By supernumerarykinds of determination the foult is estimated. The method of Drude is adapted to measurements of intensity and then applied on the glasside too. The results on this side agree with those of transmitted light, the air-side differs a little. 相似文献
59.
Kampf T Fischer A Basse-Lüsebrink TC Ladewig G Breuer F Stoll G Jakob PM Bauer WR 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2010,207(2):262-273
This study shows how applying compressed sensing (CS) to (19)F chemical shift imaging (CSI) makes highly accurate and reproducible reconstructions from undersampled datasets possible. The missing background signal in (19)F CSI provides the required sparsity needed for application of CS. Simulations were performed to test the influence of different CS-related parameters on reconstruction quality. To test the proposed method on a realistic signal distribution, the simulation results were validated by ex vivo experiments. Additionally, undersampled in vivo 3D CSI mouse datasets were successfully reconstructed using CS. The study results suggest that CS can be used to accurately and reproducibly reconstruct undersampled (19)F spectroscopic datasets. Thus, the scanning time of in vivo(19)F CSI experiments can be significantly reduced while preserving the ability to distinguish between different (19)F markers. The gain in scan time provides high flexibility in adjusting measurement parameters. These features make this technique a useful tool for multiple biological and medical applications. 相似文献
60.
Skarpos H Vorob'eva DV Osipov SN Odinets IL Breuer E Röschenthaler GV 《Organic & biomolecular chemistry》2006,4(19):3669-3674
Convenient routes to methyl 2-oxalylimino- and 2-(phosphonoformimido)-3,3,3-trifluoropropanoates have been elaborated, based on the reaction of methyl trifluoropyruvate with ethyl oxamate or diethyl carbamoylphosphonate, respectively, followed by dehydration. The compounds obtained are useful synthetic intermediates toward a variety of novel 3,3,3-trifluoroalanine derivatives that are potential drug candidates. 相似文献