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排序方式: 共有362条查询结果,搜索用时 15 毫秒
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Simaan S Marks V Gottlieb HE Stanger A Biali SE 《The Journal of organic chemistry》2003,68(2):637-640
Octakis(bromomethyl)naphthalene (4) adopts in the crystal a chiral conformation with a helical central naphthalene core and the bromomethyl groups disposed in an alternate up-down "in" arrangement. According to MM3 calculations, this conformation is less stable than the corresponding all alternated "out" form, while B3LYP/LANL2DZ calculations suggest the opposite stability order. The topomerization barrier (16.0 kcal mol(-1)) is ascribed to an enantiomerization process requiring 180 degrees rotation of all the bromomethyl groups and reversal of the helical sense of the naphthalene core. 相似文献
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P. MORLIÉRE M. BAZIN L. DUBERTRET R. SANTUS T. SA E. MELO G. HÜPPE J. HAIGLE P. FORLOT A. BERNARD 《Photochemistry and photobiology》1991,53(1):13-19
5-Geranoxypsoralen, commonly called bergamottin, a major furocoumarin contained in bergamot oil, is reported in vitro as a highly photoreactive psoralen. In ethanol, it exhibits quite a high triplet state quantum yield (approximately 0.37). The triplet state is involved in subsequent photochemistry which depends on the initial concentration and on the presence of oxygen. In contrast to most psoralens, absorption and fluorescence data suggest that 5-geranoxypsoralen does not interact with DNA in the dark. No UVA-induced interstrand cross-links in DNA were shown. 相似文献
98.
Z. J. Wu R. K. Gottlieb G. W. Burgreen J. A. Holmes D. C. Borzelleca M. V. Kameneva B. P. Griffith J. F. Antaki 《Experiments in fluids》2001,31(6):615-629
An oil dot flow visualization method was utilized in conjunction with a traditional light sheet particle tracer method to
investigate internal flow dynamics of a miniature mixed-flow blood pump. The effects of the operating condition and impeller
design on the internal fluid dynamics and hydrodynamic performance were studied. The oil dot method enabled analysis of separated
and disturbed flow within the highly wrapped rotating-blade passages – previously imperceptible with light sheet methods.
The blade wrap was found to be critical to providing a favorable fluid dynamics for blood pumping over a range of off-design
conditions. The low flow operating conditions were found to have a detrimental effect on blood flow.
Received: 13 september 2000 / Accepted: 3 April 2001 相似文献
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J. Gottlieb 《Fresenius' Journal of Analytical Chemistry》1870,9(1):251-253
Ohne Zusammenfassung 相似文献
100.
McCarthy MC Thorwirth S Gottlieb CA Thaddeus P 《Journal of the American Chemical Society》2004,126(13):4096-4097
The rotational spectrum of thiozone, S3, has been observed for the first time. From the rotational constants of the normal and 34S isotopic species, a precise geometrical structure has been derived: S3 is a bent chain with a bond to the apex S of length 1.917(1) A and an apex angle of 117.36(6) degrees . The derived structural parameters indicate substantial double-bonding character in S3 and sp2 hybridization of the central sulfur atom. Thiozone is an excellent candidate for astronomical detection in the atmosphere of Io, the innermost Galilean moon of Jupiter, and in rich interstellar sources. 相似文献