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71.
Huub Kooijman Anthony L. Spek Henk Kleijn Hendrik L. van Maanen Johann T. B. H. Jastrzebski Gerard van Koten 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):481-483
The configuration of the chiral ring atoms of the title compound, C26H26N2O, obtained in an enantioselective synthesis, has been established relative to the known R configuration of the α‐methylbenzyl moieties. The crystal packing involves a two‐dimensional network of C—H?π interactions between the aromatic rings. 相似文献
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Emanuel Vogel Hans-Wilhelm Engels Saichi Matsumoto Johann Lex 《Tetrahedron letters》1982,23(17):1797-1800
An expedient new synthesis of benzo[c]octalene starting from the Diels-Alder adduct of benzocyclobutadiene to 7,8-dimethylenecycloocta-1,3,5-triene is described. This octalene derivative, in solution, exists as an equilibrating mixture of the double bond isomers (2) and (3) whereas in its crystalline state only the isomer (2) is present. 相似文献
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The relation between sample mass andDSC-amplitude was investigated under various experimental conditions for vitreous quartz, both as discs and powders. Contrary to other authors3 proportionality has been found up to the highest masses (75 mg) used. A statistical analysis of the data indicates that the accuracy of directC p-measurements byDSC can be increased by determining the blank value by extrapolation of the amplitudes for several masses to zero mass instead of using the usual procedure, which involves a run with the empty pans. The overall error ofC p due to instrument errors is estimated not to exceed 2%. 相似文献
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Using the method of atomic-beam magnetic resonance, detected by laser-induced resonance fluorescence (ABMR-LIRF), the atomic ground-state hyperfine intervals of 50V were precisely measured. A quadrupole moment ratio is obtained which results in . 相似文献
80.
Johann Günter Krieg 《Zeitschrift für Physik A Hadrons and Nuclei》1967,205(5):425-439
This paper realizes an idea ofRedfield in a general and quantitative manner: Charged point defects produce local electric fields in a crystal which cause a change in the absorption-constant compared with the absorption-constant of an undisturbed crystal (Franz-Keldysh-effect). Thus one gets a tail in the absorption constant decreasing from the ideal intrinsic absorption edge towards longer wave-lengths. Applying an external fieldF one finds an additional, frequency-dependent absorptionconstantΔα. Its magnitude and spectral distribution depend on the concentration of defects. For external fields smaller than the internal onesΔα∝ F 2 holds at all frequencies. The results are compared with those found byFranz. 相似文献