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991.
Craig S. Harris Laurent F. Hennequin Olivier A. Willerval 《Tetrahedron letters》2005,46(45):7715-7719
A convenient 3-step multi-parallel process for the preparation of 4-(3-chloro-2-fluoroanilino)-6,7-bisalkoxyquinazolines is highlighted. 相似文献
992.
The electronic structure of Al2O3 has been studied by electron energy loss spectroscopy (ELS), and an energy level model of both filled and empty states has been constructed from the ELS and available optical data. For the high temperature pyrolytic α-polycrystalline Al2O3 films, the transitions are assumed to originate at the two principal peaks in the valence band density of states and the O(2s) core state, and to terminate on two peaks within the conduction band density of states. We also report energy loss spectra due to excitations out of the deeper Al(2p), Al(2s), Al(1s), and O(1s) core levels. The excitations originating at the Al(2p), Al(2s), and Al(1s) core levels terminate on levels in the conduction band and on an exciton lying about 1 eV below the conduction-band edge. 相似文献
993.
A bandshape study of the Raman diffusion by liquid fluorine over the temperature range 75–100°K is presented. A discussion of the molecular reorientation process is developed. 相似文献
994.
995.
M. Olivier 《Fresenius' Journal of Analytical Chemistry》1968,237(4):300
Ohne Zusammenfassung 相似文献
996.
997.
Jean Devillers Martin Cornus Jacques Navech Jean-Grard Wolf 《Magnetic resonance in chemistry : MRC》1975,7(9):411-414
The 1H NMR spectrum of the 2-dimethylamino-3-methyl 1,3,2 oxazaarsolane is very sensitive to solvent and temperature. A complete analysis of the spectrum at ?48 °C in deuteriated toluene shows that the molecule exists in a preferred conformation in the C-4? C-5 region. The spectrum, corresponding to an A2X2 system in nitrobenzene at +31 °C, indicates free movement around that bond. At higher temperatures a new coalescence phenomenon is explained by inversion of the As atom. 相似文献
998.
999.
Kronig and Penney's model is used to test a new formulation of quantum virial theorem for periodic systems. It is shown that the corrective term to the usual formulation of the virial theorem corresponding to boundary conditions is of importance and gives correct energy values for the system. Application of the virial theorem to a diatomic molecule also shows an important boundary condition correction if the distance of the nuclei is slightly different from equilibrium position, in accordance with the above correction. 相似文献
1000.
Jean Devillers Jacques Navech Jean-Pierre Albrand 《Magnetic resonance in chemistry : MRC》1971,3(2):177-186
The 31P decoupled PMR spectra of the title oxazaphospholanes give rise to well resolved ABXY patterns. Among the eight possible solutions, six can be readily eliminated from chemical shifts considerations and the choice between the remaining two is based on tickling experiments. Good fits are observed between experimental and calculated spectra. The relative signs of the 3J(P? O? C? H) and 3J(P? N? C? H) coupling constants are given by tickling and Indor experiments. The ring conformation is discussed. 相似文献