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61.
G. Kuntze und A. Hilger 《Fresenius' Journal of Analytical Chemistry》1890,29(1):707-708
Ohne Zusammenfassung 相似文献
62.
63.
Ohne Zusammenfassung 相似文献
64.
A. Hilger 《Fresenius' Journal of Analytical Chemistry》1876,15(1):115
Ohne Zusammenfassung 相似文献
65.
Sven Zschocke Thomas Hilger Burkhard Kämpfer 《The European Physical Journal A - Hadrons and Nuclei》2011,47(12):151
The operator product expansion (OPE) for heavy-light-quark pseudoscalar mesons (D -mesons and B -mesons) in medium is determined, both for a moving meson with respect to the surrounding medium as well as for a meson at
rest. First of all, the OPE is given in terms of normal-ordered operators up to mass dimension 5, and the mass of the heavy
quark and the mass of the light quark are kept finite. The Wilson coefficients of such an expansion are infrared (IR) divergent
in the limit of a vanishing light-quark mass. A consistent separation of scales necessitates an OPE in terms of non-normal-ordered
operators, which implies operator mixing, where the IR-divergences are absorbed into the operators. It is shown that the Wilson
coefficients of such an expansion are IR-stable, and the limit of a vanishing light-quark mass is perfomed. Details of the
major steps for the calculation of the Wilson coefficients are presented. By a comparison with previous results obtained by
other theoretical groups we have found serious disagreements. 相似文献
66.
67.
68.
H. Genzel E. Hilger G. Knop H. Kemen R. Wedemeyer 《Zeitschrift für Physik A Hadrons and Nuclei》1974,268(1):19-26
At the Bonn 500 MeV electron synchrotron differential cross sections of the reactionγ+p→Π 0+p were measured in the kinematical region of photon energies between 340 and 420 MeV and pionCM angles from 10° to 70° by means of detecting the two photons from the pion decay by two Cherenkov counters. 相似文献
69.
RikR. Tykwinski Anouk Hilger Franois Diederich HansPeter Lüthi Paul Seiler Volker Gramlich Jean‐Paul Gisselbrecht Corinne Boudon Maurice Gross 《Helvetica chimica acta》2000,83(7):1484-1508
Tetraethynylethenes (TEEs) functionalized with donor (4‐(dimethylamino)phenyl) and acceptor (5‐nitro‐2‐thienyl) groups were prepared by Pd0‐catalyzed Sonogashira cross‐coupling reactions (Schemes 1 – 6). The physical properties of these novel chromophores were examined and compared with those of analogous systems containing 4‐nitrophenyl instead of 5‐nitro‐2‐thienyl acceptor groups. X‐Ray crystal‐structure analyses showed the π‐conjugated frameworks of 2 , 11 , and 13 , including the TEE core and all aryl moieties, to be nearly perfectly planar (Figs. 1, 3, and 4). In contrast, one 4‐(dimethylamino)phenyl group in 10 is rotated almost 90° out of the molecular plane, presumably due to crystal‐packing effects (Fig. 2). The analysis of bond lengths and bond angles revealed little, if any, evidence of intramolecular ground‐state donor‐acceptor interactions. The electrochemical behavior of nitrothienyl‐substituted TEEs is similar to that of the corresponding nitrophenyl‐functionalized derivatives (Table 3). The nitrothienyl groups were reduced at −1.23 V (vs. the ferrocene/ferricinium couple, Fc/Fc+), regardless of the degree or pattern of other substitutions. For nonsymmetrical TEE 13 , the reduction of the nitrothienyl group at −1.23 V is followed by a reduction of the nitrophenyl group at −1.40 V, a potential typical for the reduction of other nitrophenyl‐substituted TEEs, such as 17 – 20 . UV/VIS Spectroscopy showed a consistently lower‐energy absorption cutoff for nitrothienyl derivatives compared with the analogous nitrophenyl‐substituted TEEs that confirms a lowering of the HOMO‐LUMO gap as a result of nitrothiophene substitution (Figs. 5 and 6). A comparison of the tetrakis‐arylated TEEs 11 , 13 , and 20 clearly showed a steady bathochromic shift of the longest‐wavelength absorption maximum and the end‐absorption upon sequential replacement of nitrophenyl by nitrothienyl groups. Quantum‐chemical computations were performed to explain a number of complex features of the electronic absorption spectra. All empirical features of relevance in the experimental UV/VIS spectra for 2 , 5 , 6 , and 17 – 19 were correctly reproduced by computation (Tables 4 and 5). The combination of theory and experiment was found to be very useful to explain the particular acceptor properties of the 5‐nitro‐2‐thienyl group. 相似文献
70.
We have observed edge diffraction with a double crystal diffractometer and therefore can explain the enhanced wing intensity of measured Darwin profiles in dynamical diffraction. Precise experiments uniquely demonstrate the contribution of Fresnel diffraction at absorbing straight edges, interpreted as ultra small angle scattering (USAS) or diffuse scattering in other experiments. No contributions were found due to ultra small surface scattering or TDS stemming from the crystals, which was proposed by other groups to explain the enhanced wing intensity of their measured rocking curves. 相似文献