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171.
172.
173.
Novel stilbenes as probes for amyloid plaques. 总被引:7,自引:0,他引:7
H F Kung C W Lee Z P Zhuang M P Kung C Hou K Pl?ssl 《Journal of the American Chemical Society》2001,123(50):12740-12741
174.
J. Plášek 《Molecular Crystals and Liquid Crystals》2013,570(1-4):23-33
The excitation wavelength dependence of luminescence measured in adenine cation crystals at 77 K is reported. The observed variations of all the luminescence parameters exhibit a marked correlation with a changing penetration depth of the excitation light. The alterations of luminescence intensity, vibronic structure of emission spectra, emission polarization and phosphorescence decay were attributed mainly to a variable contribution of the emission from local excited states which correspond to a different trap ensembles in the crystal bulk and near the surface, respectively. 相似文献
175.
176.
177.
Juliette Sabbatani Prof. Dr. Nuno Maulide 《Angewandte Chemie (International ed. in English)》2016,55(23):6780-6783
A novel formal [3+2] cycloaddition of cyclopropylacetals and aldehydes was developed, and the resulting trisubstituted tetrahydrofurans display three new chiral centers formed with highly diastereoselectivity. This method is stereocomplementary to most previously reported cycloadditions of malonate diesters, relies on the transient generation of cyclopropyl oxocarbenium ions, proceeds under mild conditions, and is based on the concept of temporary activation of an otherwise inert protecting group. 相似文献
178.
J. Becker H.G. Andresen J.R.M. Annand K. Aulenbacher K. Beuchel J. Blume–Werry Th. Dombo P. Drescher M. Ebert D. Eyl A. Frey P. Grabmayr T. Großmann P. Hartmann T. Hehl W. Heil C. Herberg J. Hoffmann J.D. Kellie F. Klein K. Livingston M. Leduc M. Meyerhoff H. Möller Ch. Nachtigall A. Natter M. Ostrick E.W. Otten R.O. Owens S. Plützer E. Reichert D. Rohe M. Schäfer H. Schmieden R. Sprengard M. Steigerwald K.-H. Steffens R. Surkau Th. Walcher R. Watson E. Wilms 《The European Physical Journal A - Hadrons and Nuclei》1999,6(3):329-344
The electric form factor of the neutron GEn has been determined in double polarized exclusive 3
He(e,e'n) scattering in quasi–elastic kinematics by measuring asymmetries A
⊥, A
∥ of the cross section with respect to helicity reversal of the electron, with the nuclear spin being oriented perpendicular
to the momentum transfer q in case of A⊥ and parallel in case of A∥. The experiment was performed at the 855 MeV c. w. microtron MAMI at Mainz. The degree of polarization of the electron beam
and of the gaseous 3
He target were each about 50%. Scattered electrons and neutrons were detected in coincidence by detector arrays covering large
solid angles. Quasi–elastic scattering events were reconstructed from the measured electron scattering angles ϑe, φe and the neutron momentum vector p
n
′ in the plane wave impulse approximation. We obtain the result <G
En>(0.27 < Q2c2/GeV2 < 0.5)= 0.0334 ± 0.0033stat± 0.0028syst which is averaged over the indicated range of Q
2, the squared momentum transfer. This G
En value is significantly smaller than measured from the D(e,e'n) reaction under similar kinematical conditions. To what extent final state interactions in 3He quench the G
En result is subject of calculations currently in progress elsewhere.
Received: 29 April 1999 相似文献
179.
H. J. Andrä H. J. Plöhn A. Gaupp R. Fröhling 《Zeitschrift für Physik A Hadrons and Nuclei》1977,281(1-2):15-20
It is shown that nuclear spin polarized ion beams can be generated by ion beam surface interaction at grazing incidence. An optical detection method for the nuclear polarization after foil excitation of such beams is described and used for a hyperfine structure quantum-beat measurement on the14N II ?2p 3p 3 D-state. 相似文献
180.
Serge Nicaise Juliette Venel 《Journal of Computational and Applied Mathematics》2011,235(14):4272-4282
We perform the a posteriori error analysis of residual type of transmission problem with sign changing coefficients. According to Bonnet-BenDhia et al. (2010) [9], if the contrast is large enough, the continuous problem can be transformed into a coercive one. We further show that a similar property holds for the discrete problem for any regular meshes, extending the framework from Bonnet-BenDhia et al. [9]. The reliability and efficiency of the proposed estimator are confirmed by some numerical tests. 相似文献