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61.
Gerhard Englert 《Fresenius' Journal of Analytical Chemistry》1961,181(1):447-455
Ohne Zusammenfassung 相似文献
62.
An additional splitting of Shubnikov-de Haas oscillations in (lll) n-type silicon inversion layers in observed. We attribute it to valley splitting, analogous to that previously observed on (100) surface layers, and point out that theoretical explanations of valley splitting, restricted to the valley configuration in (100) inversion layers, are not applicable. 相似文献
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66.
A. Büling C. Carl P. Englert U. Herpers W. Herr R. Michel P. Ney H. Weigel 《Journal of Radioanalytical and Nuclear Chemistry》1977,38(1-2):379-390
In a large number of alpine rocks and respective mineral separates the beryllium distribution was studied via “non-destructive”
photon activation. The detection limit of the assembly was ∼20 ppb. The existence of Be-rich areas was revealed. A selection
of individual rocks was analysed by instrumental as well as by radiochemical neutron activation analysis for main and trace
elements as: Na, K, Sc, Cr, Mn, Fe, Co, Rb, Cs, La, Eu, Yb, Ta, W, Au, and U. The latter was determined by counting the235U-fission tracks. The data supply an insight into the complex processes leading to the formation of metamorphic rocks. The
hardware and the computer evaluation of the γ-spectra is described in some detail. A further application is the determination
of traces of53Mn (in the order of 10−12 g/g) produced by the interaction of cosmic rays with stony meteorites. From a comparison of the26Al- and53Mn-values it is concluded that the depth dependent production of these two radionuclides differs slightly. 相似文献
67.
We investigate the discrete chiral transformation of a Majorana fermion on a torus. Depending on the boundary conditions the integration measure can change sign. Taking this anomalous behavior into account we define a chiral order parameter as a ratio of partition functions with differing boundary conditions. Then the lattice realization of the Gross–Neveu model with Wilson fermions is simulated using the recent ‘worm’ technique on the loop gas or all-order hopping representation of the fermions. An algorithm is formulated that includes the Gross–Neveu interaction for N fermion species. The critical line mc(g) is constructed for a range of couplings at N=6 and for N=2, the Thirring model, as examples. 相似文献
68.
Lars Müller-Meskamp Rainer Waser Melanie Homberger Ulli Englert 《Surface science》2009,603(4):716-8968
The self-assembly of ω-ferrocenylalkanethiols (FcCnSH) with different alkyl-spacer lengths on Au(1 1 1) substrates has been studied by scanning tunneling microscopy (STM). Upon deposition at room temperature FcCnSH molecules tend to form multilayers, while by thermal treatment monolayer formation, a rearrangement of the molecules and the formation of ordered domains is achieved. The surface structure of the resulting full coverage self-assembled monolayers is resolved with molecular resolution by STM. The ordered monolayer structure of ω-ferrocenylpropanethiol is discussed in comparison with its bulk crystal structure, derived from single crystal X-ray analysis. Based on these results a monolayer structure of ω-ferrocenylalkanethiols with longer alkyl chains closely related to the bulk crystal structure of the shorter alkyl-spacer derivates is suggested. Our results provide detailed insight into the self-assembly of FcCnSH on gold substrates. 相似文献
69.
Tim Hammerer Laurent Weisgerber Stefan Schenk Othmar Stelzer Ulli Englert Walter Leitner Giancarlo Franciò 《Tetrahedron: Asymmetry》2012,23(1):53-59
New diphosphinite ligands based on atropoisomeric diol backbones and (R,R)-2,5-dimethylphospholane moieties have been prepared and fully characterised. For each ligand structure, both diastereomers have been synthesised. These ligands are available through a straightforward procedure in good yields. The solid state structures of two diastereomeric ligands are reported. These ligands have been applied to Rh-catalysed asymmetric hydrogenations and hydroformylations of CC bonds as well as in Ir-catalysed asymmetric hydrogenations of CN bonds. Turnover frequencies in the range of 10,000 h?1 and enantioselectivities of up to 98% ee have been achieved. The different chirality elements within the ligands led to marked cooperative effect in catalysis. Interestingly, there is no general privileged diastereomeric structure but rather a matched diastereomer for each application. 相似文献
70.
Both ATLAS and CMS have reported a discovery of a Standard Model-like Higgs boson H of mass around 125 GeV. Consistency with the Standard Model implies the non-observation of non-SM-like decay modes of the newly discovered particle. Sensitivity to such decay modes, especially when they involve partially invisible final states is currently beyond scrutiny of the LHC. We systematically study such decay channels in the form of H→AA→jets+missing energy, with A a light scalar or pseudo-scalar, and analyze to what extent these exotic branching fractions can be constrained by direct measurements at the LHC. While the analysis is challenging, constraints as good as BR?10% can be obtained. 相似文献