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221.
Frank Marlow Dr. Muldarisnur Parvin Sharifi Rainer Brinkmann Cecilia Mendive Dr. 《Angewandte Chemie (International ed. in English)》2009,48(34):6212-6233
The beauty of opals results from a densely packed, highly ordered arrangement of silica spheres with a diameter of several hundred nanometers. Such ordered nanostructures are typical examples of materials called photonic crystals, which can be formed by known microstructuring methods and by self‐assembly. Opals represent a self‐assembly approach to these structured media; such an approach can lead to novel materials for photonics, photocatalysis, and other areas. Although self‐assembly leads to many types of defects, resulting in the surprising and very individual appearance of natural opals, it causes also difficulties in technological applications of opal systems. 相似文献
222.
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224.
Mohammad-Reza. Rouini Yalda H. Ardakani Alireza Foroumadi Hoda Lavasani Lida Hakemi 《Chromatographia》2009,70(5-6):953-956
A rapid LC method with UV detection was developed for the quantification of carboxylic acid metabolite of clopidogrel in human plasma. Following a simple protein precipitation using a mixture of methanolic solution of ZnSO4, the analyte and commercially available internal standard were separated using a mobile phase of water–acetonitril (85:15, v/v) adjusted to pH 3.5 on a Chromolith C18 column at a flow rate of 2.5 mL min?1 with a total retention time of 4 min. Linearity was verified over the range of 20–3,000 ng mL?1 where the LOQ was 20 ng mL?1. This method was applied in a pharmacokinetic study. 相似文献
225.
In this paper characterization of maximally looped complex curves is discussed and a relation between the number of double points and the number of loops is presented. Also we calculate the rotation number of maximally looped complex curves and compute the number σ of double tangents for those without inflection points. 相似文献
226.
Optical spectra and angular dependence of electromagnetic emission from Al-Al oxide-Ag and Al-Al oxide-Au tunnel junctions are reported. Data from Ag junctions are consistent with the assumption of roughness induced decoupling of surface polaritons, while data from Au junctions suggest that the emission results from direct coupling of current fluctuations in the junction to the external radiation fields. 相似文献
227.
Reza?GhiasiEmail author Sarvin?Hossien?Saraf Hoda?Pasdar 《Monatshefte für Chemie / Chemical Monthly》2018,149(12):2167-2174
228.
Second-order rate constants are reported for the cleavage of the phenyltin bond of phenyltriethyltin by mercury(II) salts in ethanol. propan-1-ol, propan2-ol and butan-1-ol. It is shown that the reactivity order for the mercury(II) salts is HgI3? << HgI2 < HgCl2. Activation parameters are reported, and on the basis of the low values of activation enthalpies the presence of an intermediate π-complex is suggested for the reactions. 相似文献
229.
Abu T. Khan Lokman H. Choudhury Tasneem Parvin Md. Asif Ali 《Tetrahedron letters》2006,47(46):8137-8141
A convenient method for the preparation of β-acetamido carbonyl compounds is described by multi-component reactions of aromatic aldehydes, enolizable ketones or β-keto esters and acetonitrile in the presence of acetyl chloride and 10 mol % CeCl3·7H2O at room temperature. 相似文献
230.
J. C. Lima Parvin Danesh Paulo Figueiredo Fernando S. Pina António Maçanita 《Photochemistry and photobiology》1994,59(4):412-418
Abstract The excited state properties of the chalcone isomers of malvidin 3,5-diglucoside (malvin) in acidic aqueous solution (0 < pH < 4) were investigated using steady-state and time-resolved fluorescence spectroscopy. The two chalcone isomers of malvin were first isolated by high-performance liquid chromatography and then characterized by UV/visible absorption and fluorescence spectroscopy. The results were supported by molecular orbital calculations. The rate constants for photodeprotonation ( k 1 = 1 × 109 s−l ) and protonation ( k −1 = 1.3 × 1010 L mol−1 s−l ) were determined, both from the multiexponential fluorescence decays and the fluorescence intensities measured at the emission wavelengths of the neutral and ionized chalcone forms. The results here obtained are relevant for the understanding of the photoreactivity of anthocyanins in acidic medium. 相似文献