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61.
62.
Gilbert Dana Feiga Weisbuch Brigitte Lo Cicero Jean-Michel Drancourt Jacqueline Mercier 《Tetrahedron》1985,41(7):1241-1249
We show that the four studied 4-hydrindenones (with or without a methyl substituant at C3 or C7a) give by hydrogenation on Raney nickel or on Pd/C, in various solvants, the cis 4-hydrindanones, by a kinetically controlled process. During the hydrogenation, the double bond can migrate only in the positions conjugated to the carbonyl group.In contrast, when the carbonyle is protected as a dioxolanne, the double bond is free to migrate around the five membered ring. In spite of this mobility the optical purity of the saturated dioxolannes formed is high. In the case of the (+)3-methyl Δ3(3a) 4-hydrindenone, the enantiomeric hydrindanones obtained by direct hydrogenation or with isomerization of the double bond are not the same. Therefore, the optical purity of the product is low, but its value allows an estimation of the relative importance of the two reaction pathways. 相似文献
63.
64.
François Treussart Nicolas Dubreuil Jongthan Cave Knight Vahid Sandoghdar Jean Hare Valçrie Lefçvre-Seguin Jean-Michel Raimond Serge Haroche 《电信纪事》1997,52(11-12):557-568
Light can be confined efficiently in the high-Q, small-volume whispering-gallery-modes observed in silica microspheres. By coupling these microspheres to eroded optical fibers and fiber tips, direct mapping of the whispering-gallery modes has been achieved and the mode numbers have been assessed. The properties of these modes have allowed us to obtain laser action with very low thresholds in Nd-doped silica microspheres. Further projects in the field of non-linear optics and cavity quantum electrodynamics are described. 相似文献
65.
Lavandier M Jelfs S Culling JF Watkins AJ Raimond AP Makin SJ 《The Journal of the Acoustical Society of America》2012,131(1):218-231
When speech is in competition with interfering sources in rooms, monaural indicators of intelligibility fail to take account of the listener's abilities to separate target speech from interfering sounds using the binaural system. In order to incorporate these segregation abilities and their susceptibility to reverberation, Lavandier and Culling [J. Acoust. Soc. Am. 127, 387-399 (2010)] proposed a model which combines effects of better-ear listening and binaural unmasking. A computationally efficient version of this model is evaluated here under more realistic conditions that include head shadow, multiple stationary noise sources, and real-room acoustics. Three experiments are presented in which speech reception thresholds were measured in the presence of one to three interferers using real-room listening over headphones, simulated by convolving anechoic stimuli with binaural room impulse-responses measured with dummy-head transducers in five rooms. Without fitting any parameter of the model, there was close correspondence between measured and predicted differences in threshold across all tested conditions. The model's components of better-ear listening and binaural unmasking were validated both in isolation and in combination. The computational efficiency of this prediction method allows the generation of complex "intelligibility maps" from room designs. 相似文献
66.
Bouchoul Nassim Fourré Elodie Tatibouët Jean-Michel Batiot-Dupeyrat Catherine 《Plasma Chemistry and Plasma Processing》2019,39(3):713-727
Plasma Chemistry and Plasma Processing - The coupling of catalyst and nonthermal plasma for the dry reforming of methane was investigated with a special attention to the textural and structural... 相似文献
67.
68.
Gielen E Smisdom N De Clercq B Vandeven M Gijsbers R Debyser Z Rigo JM Hofkens J Engelborghs Y Ameloot M 《Journal of fluorescence》2008,18(5):813-819
Many membrane proteins and lipids are partially confined in substructures ranging from tens of nanometers to micrometers in
size. Evidence for heterogeneities in the membrane of oligodendrocytes, i.e. the myelin-producing cells of the central nervous
system, is almost exclusively based on detergent methods. However, as application of detergents can alter the membrane phase
behaviour, it is important to investigate membrane heterogeneities in living cells. Here, we report on the first investigations
of the diffusion behavior of the myelin-specific protein MOG (myelin oligodendrocyte glycoprotein) in OLN-93 as studied by
the recently developed RICS (raster-scanning image correlation spectroscopy) technique. We implemented RICS on a standard
confocal laser-scanning microscope with one-photon excitation and analog detection. Measurements on FITC-dextran were used
to evaluate the performance of the system and the data analysis procedure.
Ellen Gielen and Nick Smisdom contributed equally to this work. 相似文献
69.
Hétérocycles à fonction quinone. 7. Benzo[f]quinazolinediones-7,10 à action antitumorale potentielle
Hlne Parrot-Lopez Jean-Michel Delacotte Jean Renault Suzanne Cros 《Journal of heterocyclic chemistry》1986,23(4):1039-1043
Few benzo[f]quinazoline-7,10-diones 4a-c are prepared by oxidation, with potassium nitrosodisulfonate, of the corresponding benzo[f]quinazolinamines, made by reduction of the nitro analogues which were obtained from 8-methoxybenzo[f]quinazolin-1(2H)-one. The compound 4a shows an interesting cytotoxicity. 相似文献
70.
Our efforts in construction the 1,2-dioxane ring of plakortolides through two approaches are described. The first one involved as a key step an acid catalyzed 6-endo ring closure of β-hydroperoxy trans-epoxides directed by a vinyl group adjacent to the epoxide function. By this route, an advanced intermediate of plakortolides was obtained in six steps and 35% overall yield. The second approach featured a 1,2-dioxane ring forming by a double opening of bis-epoxides by ethereal hydrogen peroxide. This reaction did not proceed in the expected sense and exclusive formation of hydroperoxy tetrahydropyran derivatives was observed via a tandem oxacyclization–hydroperoxidation sequence. 相似文献