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Excess noise in Bi whiskers was measured as a function of temperature from 50 to 350 K. The noise is approximately 100 times larger than in films and nearly constant from 50 to 250 K where a sharp increase is observed. The noise did not disappear when was zero, nor was any correlation between the exponent of the inverse power law and the temperature found. 相似文献
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van Eis MJ Wijsman GW de Wolf WH Bickelhaupt F Rogers DW Kooijman H Spek AL 《Chemistry (Weinheim an der Bergstrasse, Germany)》2000,6(9):1537-1546
The course of the hydrogenation of [5]- and [6]metacyclophane (1b and 1c) and their thermochemistry is described. Both compounds are hydrogenated rapidly (within 10 s) to furnish the bridgehead olefins 13b and 12c. The accompanying hydrogenation enthalpies are -220 and -141 kJmol(-1), respectively. Strain energies (SE) and olefinic strains (OS) of a number of bridgehead olefins have been evaluated by DFT calculations; it was concluded that 13b belongs to the class of hyperstable olefins which correlates nicely with its reluctance to undergo hydrogenation. By combining experimental hydrogenation enthalpies and DFT calculations, SE of 187 and 121 kJmol(-1) were derived for 1b and 1c. 相似文献
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