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71.
It is usually assumed that the holding current of an amorphous semiconductor threshold switch is not strongly dependent on the circuit surrounding the switch. This paper shows that the holding current is in fact controlled by both the series resistance and the parallel capacitance, according to two simple inequalities. In order to obtain low holding currents a large series resistor and minimum parallel capacitance are required, and in this way a holding current of 10 μA has been observed. Data are also presented on the effects of device dimensions and temperature on the on-state I-V curves and holding current. 相似文献
72.
Enda Bergin David L. Hughes Christopher J. Richards 《Tetrahedron: Asymmetry》2010,21(11-12):1619-1623
Reaction of (η5-cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt with Hg(OAc)2 (2.3 equiv) in 1:1 MeOH/CH2Cl2 followed by the addition of LiCl resulted in the formation of (η5-1,2-dichloromercuricyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt (33%) and its 1,3-isomer (6%). Following conversion into their corresponding diiodides these compounds were desymmetrised by Suzuki reactions with ArB(OH)2 employing [(R)-BINAP]PdCl2, with the highest ee of 24% being obtained for (η5-1-iodo-3-(2-methoxyphenyl)cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt. 相似文献
73.
74.
75.
Ohne Zusammenfassung 相似文献
76.
Crystal and molecular structure of 5,12a-diacetyloxytetracycline 总被引:1,自引:0,他引:1
77.
1H NMR studies of an equilibrium mixture of 1,1,1,5,5,5-hexafluoropentane-2,4-dionato-π-allylplatinum(II) [IA] and bis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato)bis(μ-allyl)diplatinum(II) [IB] show that the μ-allylic ligands of (IB) exhibit temperature dependent tautomeric behaviour, giving rise to a site-exchange between protons on these ligands. 相似文献
78.
O.H. Hughes J.C. Woolley S.A. Lopez-Rivera B.R. Pamplin 《Solid State Communications》1980,35(8):573-575
The preparation of a range of polycrystalline Selenides and Tellurides of the form I III IV VI4 was undertaken. Twelve Selenides with quaternary composition were prepared but the eight Tellurides attempted did not grow as quaternaries. Single crystal samples of CuGaSnSe4 were grown by vapour transport. X-Ray powder photography confirmed that the quaternary Selenides have tetragonal Chalcopyrite structure with a c/a ratio of approximately 2. A systematic variation of unit cell volume and of c/a was found over the entire range of compounds grown. 相似文献
79.
80.
The shape and moments of the F+ absorption band in SrO have been measured between 4.2K and 300K. Analysis of the moments gives the effective frequency of the vibrational modes interacting with the centre as , and the Huang-Rhys factors for cubic and non-cubic modes as SC = 3 ± 1 and SNC = 4 ± 1 respectively. 相似文献