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排序方式: 共有3021条查询结果,搜索用时 15 毫秒
21.
A. Hempel B. G. Lane N. Camerman 《Acta Crystallographica. Section C, Structural Chemistry》1997,53(11):1707-1709
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John Cagnol Irena Lasiecka Catherine Lebiedzik Richard Marchand 《Comptes Rendus Mathematique》2006,342(9):711-716
This note is concerned with the non-linear shallow shell model introduced in 1966 by W.T. Koiter, and later studied by M. Bernadou and J.T. Oden. We show the uniqueness of the solution to the dynamical model and that this solution is continuous with respect to the initial data. To cite this article: J. Cagnol et al., C. R. Acad. Sci. Paris, Ser. I 342 (2006). 相似文献
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Appleby I Boulton LT Cobley CJ Hill C Hughes ML de Koning PD Lennon IC Praquin C Ramsden JA Samuel HJ Willis N 《Organic letters》2005,7(10):1931-1934
Two methods to produce (2S)-5-amino-2-(1-n-propyl-1H-imidazol-4-ylmethyl)-pentanoic acid were investigated. Diastereoisomeric salt resolution, using the quinidine salt, gave the desired intermediate in 98% ee and 33% yield. Asymmetric hydrogenation of various substrates gave high conversions, with up to 83% ee. Integration of these two approaches via asymmetric hydrogenation of a quinidine salt substrate followed by crystallization provided the desired intermediate in 94% ee and 76% yield. 相似文献
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Joël J. E. Moreau Luc Vellutini Catherine Bied Michel Wong Chi Man 《Journal of Sol-Gel Science and Technology》2004,32(1-3):63-67
The acid-hydrolysis of an organo-bridged bisdiethoxysilylated molecular precursor bearing urea groups, (EtO)2MeSi(CH2)3NHCONH(CH2)12NHCONH(CH2)3SiMe(OEt)2, has been performed in pure aqueous medium. Scanning electron microscopy (SEM) analysis of the resulting insoluble solid revealed plate-like forms with a lamellar structure as determined by powder X-ray diffraction (PXRD) studies with a sharp peak at 28.5 Å. The solid state 29Si MAS-NMR spectrum of this bridged siloxane hybrid is consistent with a moderately condensed material with complete preservation of the Si–C bonds throughout the hybrid network. In comparison, the classical sol–gel hydrolysis-condensation of the molecular precursor in ethanol with stoichiometric amount of water and fluoride anion as catalyst produced an amorphous featureless solid. 相似文献
29.
Syntheses of Two Potential Ligands for Tc-99m Labeling as Diagnosis Agents of Alzheimer''''s Disease
Two types of ligands-biphenyl and stilbene derivatives, whichcan be labeled with Tc-99m for the diagnosis of Alzheimer'sdisease (AD) have been synthesized successfully. The key stepsin these two syntheses involved Suzuki reaction and Wittig reac-tion respectively. The new discovered debromination reactionmay be expanded to the compounds with double or triple bondadjacent to the carbon atom bearing the bromine atoms. Thesetypes of syntheses provide a route to a series of biphenyl andstilbene derivatives that will benefit the search of new imagingagents for AD. 相似文献
30.
C. A. Rinaldi J. C. Ferrero S. I. Lane E. V. Oexler 《Journal of Chemical Sciences》1991,103(3):465-469
The IR multiphoton dissociation of CF3I has been studied in the presence of isobutane and with isobutane and Ar and CO2 as inert gases. The dependence of the reaction probability P(Φ) with fluence (ϕ) is confirmed. Modeling of the experimental results shows that for the energy transfer processes the average energy transferred
per collision 〈†E〉d varies with (ϕ). 相似文献