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51.
52.
Programmable axial apodizing and hyperresolving amplitude filters with a liquid-crystal spatial light modulator 总被引:3,自引:0,他引:3
Amplitude-transmitting filters for apodizing and hyperresolving applications can be easily implemented by use of a two-dimensional programmable liquid-crystal spatial light modulator operating in a transmission-only mode. Experimental results are in excellent agreement with theoretical predictions. This approach can permit the analysis of various filter designs and can allow the filters to be changed rapidly to modify the response of an optical system. 相似文献
53.
A kinetic and product study of the dichloroacetic acid catalyzed chlorination of 1-methylpyrrole with 3- and 4-substituted N-chlorobenzamides was carried out. Protonated N-chlorobenzamides served as carriers of CI+. A Hammett correlation was obtained with ρ=−0.68 (r=0.98, n=8). General acid catalysis was observed with α=0.48 (r=0.99 and n=7). The yields of 2-chlorination (84±0.7%) and 3-chlorination (2.6±0.4%) were essentially constant (constant intramolecular selectivity) as the substituent on the N-chlorobenzamide was varied. Observation of constant intramolecular selectivity indicated that two intermediates were formed during the acid catalyzed chlorination of 1-methylpyrrole with N-chlorobenzamides. The carrier method is applicable to all types of aromatic systems and limited only by the availability of suitable carrier molecules. 相似文献
54.
Cecilio Marquez Rosa M. Rabanal Serafiin Valverde Liliana Eguren Aurea Perales Jos Fayos 《Tetrahedron letters》1980,21(52):5039-5042
Two diterpenes, capitatin 4 and teucapitatin 5 have been isolated from Teucrium capitatum. The X-ray structure of 4, including absolute stereochemistry, is given. Diterpene 4 has been chemically related to picropolin 1 and picropolinone 2, thereby establishing the absolute stereochemistry of these two neoclerodane-type diterpenes. 相似文献
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William H. GerwickPauline Leslie G.Cliona LongBrian L. Marquez Christine L. Willis 《Tetrahedron letters》2003,44(2):285-288
[6-13C]-(2S,4S)-5-Chloroleucine 12 was prepared in six steps and 26% overall yield from protected l-glutamic acid using 13CH3I as the source of isotopic label. On feeding 12 to cultures of L. majuscula no incorporation of isotopic label into the trichlorinated marine natural product barbamide was detected. The synthesis of a novel dichloroleucine derivative 16 is also described. 相似文献
57.
Antonio A. García Ana Egatz-Gómez Solitaire A. Lindsay P. Domínguez-García Sonia Melle Manuel Marquez Miguel A. Rubio S.T. Picraux Dongqing Yang P. Aella Mark A. Hayes Devens Gust Suchera Loyprasert Terannie Vazquez-Alvarez Joseph Wang 《Journal of magnetism and magnetic materials》2007
Magnetic fields can be used to control the movement of aqueous drops on non-patterned, silicon nanowire superhydrophobic surfaces. Drops of aqueous and biological fluids are controlled by introducing magnetizable carbonyl iron microparticles into the liquid. Key elements of operations such as movement, coalescence, and splitting of water and biological fluid drops, as well as electrochemical measurement of an analyte are demonstrated. Superhydrophobic surfaces were prepared using vapor–liquid–solid (VLS) growth systems followed by coating with a perfluorinated hydrocarbon molecule. Drops were made from aqueous and biological fluid suspensions with magnetizable microparticle concentrations ranging from 0.1 to 10 wt%. 相似文献
58.
[reaction: see text] Intramolecular cyclopropanation of a carbene engendered from the corresponding diazo beta-ketoester produced the desired bicyclo[3.1. 0]hexane pseudosugar. Purine nucleosides obtained via Mitsunobu coupling were resolved with adenosine deaminase. The requisite beta-ketoester was assembled in one step from ethyl acetoacetate and acrolein. 相似文献
59.
Kang JH Siddiqui MA Sigano DM Krajewski K Lewin NE Pu Y Blumberg PM Lee J Marquez VE 《Organic letters》2004,6(14):2413-2416
[structure: see text] Commercially available 2-methylenepropane-1,3-diol was converted to chiral epoxide (R)-2 via Sharpless asymmetric epoxidation in >96% ee. Regiospecific epoxide ring opening and reduction of the intermediate alkyne set the stage for a one-pot lactonization to give (R)-6, a convenient precursor for all functionalized chiral DAG-lactones used as potent PK-C ligands. The synthesis of the most potent DAG-lactones known to date, (Z)-10 and (E)-10, served to confirm PK-C's exclusive preference for the (R)-stereochemistry in this class of compounds. 相似文献
60.