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91.
The photogalvanic effect has been studied in three systems using photogalvanic cells and NaLS-ascorbic acid-azur A, NaLS-ascorbic
acid-azur B, NaLS-ascorbic acid-azur C systems. The photopotential and photocurrent generated by these systems are 7700, 9710,
623·0 mV and 160·0, 185·0, 145·0 (μA respectively. The effects of different parameters on the electrical outputs of the cell have been observed and current-voltage
characteristics of the cell studied, and a mechanism has been proposed for the generation of photocurrent in photogalvanic
cells. The conversion efficiencies for azur A, azur B and azur C are 0·5461, 0·9646 and 0·4567% and storage capacity 110,
135 and 95 min respectively. 相似文献
92.
93.
Dheer Singh Anju Chopra Mitra Bhanu Patel Amarjit Singh Sarpal 《Chromatographia》2011,74(1-2):121-126
Although the concentration of nitrogen compounds in crude oil is relatively low, they can become more concentrated in petroleum distillates and poison the catalysts used in refining processes. They cause undesirable deposits, color formation and odor in products; they also contribute to air pollution and some are highly carcinogenic. The poisoned catalyst becomes deactivated for hydrodesulfurization and unable to remove sulfur from middle distillates. In order to understand the effect on catalytic processes, it is desirable to identify the nitrogen compounds in various petroleum distillates. This paper compares the nitrogen species profiles in different petroleum distillates using a nitrogen chemiluminescence detector. In addition, four different petroleum distillate samples from different refineries were analyzed to find the variation in their nitrogen profiles. The nitrogen compounds in petroleum distillate samples were identified as anilines, quinolines, indoles, and carbazoles and their alkyl derivatives. Quantitation was carried out against known reference standards. The quantitative data were compared to the total nitrogen content determined by elemental analysis. 相似文献
94.
Chemical and genetic modifications on the surface of viral protein cages confer unique properties to the virus particles with potential nano and biotechnological applications. The enclosed space in the interior of the virus particles further increases its versatility as a nanomaterial. In this paper, we report a simple method to generate a high yield of stable cowpea mosaic virus (CPMV) empty capsids from their native nucleoprotein counterparts by removing the encapsidated viral genome without compromising the integrity of the protein coat. Biochemical and structural comparison of artificially generated empty particles did not reveal any distinguishable differences from CPMV particles containing viral RNA. Preliminary results on the use of artificially produced empty CPMV capsids as a carrier capsule are described. 相似文献
95.
Nanoparticles, bulk and thin films of NiFe2 O4 compounds are studied by micro‐Raman spectroscopy. The effect of varying the incident laser power up to 40 mW was studied in all forms of the samples. The spectra showed a large magnitude of red shift and line broadening as a result of high incident laser power. It is shown that the inverse spinel structure remains robust, and no trace of laser‐induced oxidation was observed. The low‐temperature study of the bulk and nanoparticles has also been carried out for elucidating thermal effects due to the high incident laser power. The rise in temperature for maximum incident laser power of 40 mW was estimated to be ∼625 °C. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
96.
97.
Baburaj Baskar N. Ganesh Pandian Kuttikode Priya Anju Chadha 《Tetrahedron: Asymmetry》2004,15(24):3961-3966
Enantioselective bioreduction of alkyl 2-oxo-4-arylbutanoates and 2-oxo-4-arylbut-3-enoates mediated by Candida parapsilosis ATCC 7330 resulted in the formation of the corresponding (S)-2-hydroxy compounds in high enantiomeric excesses (93–99%) and good isolated yields (58–71%). The absolute configuration of enantiomerically pure ethyl 2-hydroxy-4-(p-methylphenyl)but-3-enoate obtained by the reduction of the corresponding keto ester was assigned by 1H NMR using Mosher’s method. 相似文献
98.
Cowpea mosaic virus (CPMV) is a robust, icosahedrally symmetric platform successfully used for attaching a variety of molecular substrates including proteins, fluorescent labels, and metals. The symmetric distribution and high local concentration of the attached molecules generates novel properties for the 30 nm particles. We report new CPMV reagent particles generated by systematic replacement of surface lysines with arginine residues. The relative reactivity of each lysine on the native particle was determined, and the two most reactive lysine residues were then created as single attachment sites by replacing all other lysines with arginine residues. Structural analysis of gold derivatization not only corroborated the specific reactivity of these unique lysine residues but also demonstrated their dramatically different presentation environment. Combined with site-directed cystine mutations, it is now possible to uniquely double label CPMV, expanding its use as an addressable nanoblock. 相似文献
99.
Summary The kinetics of oxidation of amines (EtNH2, Et2NH, Et3N) and aminoalcohols [H2NCH2CH2OH, H2N(CH2)3OH, (CH2CH2OH)2NH, (CH2CH2OH)3N] by N-bromosuccinimide (NBS) have been studied in aqueous HClO4 with PdCl2 as catalyst, and in the presence of Hg(OAc)2 to ensure oxidation by pure NBS. The order of reaction with respect to NBS was unity, however, an increase in [NBS]0 resulted in a decrease in the rate constant. The rate was directly proportional to [PdII] for the aminoalcohols while for EtNH2 the rate was proportional to k + k[PdII] (where k and k are rate constants for the uncatalysed and catalysed paths, respectively). Retarding effects for HClO4, succinimide, Cl– and AcOH on the rate of oxidation were observed. The kinetic data support the formation of [PdII-A] and [PdII-(A)2] complexes (where A represents amine or aminoalcohol). A mechanism, consistent with the observed kinetic data, is proposed. 相似文献
100.
A spectrophotometric method to determine palladium(II) at trace levels is based on the extraction of palladium(II) as a binary complex with N-hydroxy-N,N′-diphenylbenzamidine (HDPBA) in chloroform at pH 5.0 ± 0.2. The complex shows maximum absorbance at 400 nm with molar absorptivity 6.4 × 103 L mol?1 cm?1. The sensitivity of the Pd(II)-HDPBA complex was enhanced by the addition of l-(2-pyridylazo)-2-naphthol (PAN). The green coloured complex shows maximum absorbance at 620 nm with molar absorptivity 1.58 × 104 L mol?1 cm?1. Sandell's sensitivity and the detection limit of the method are 0.0067 μg cm?2and 0.1 μg Pd(II) mL?1, respectively. Most common metal ions associated with palladium metal do not interfere. The effects of various analytical parameters on the extraction of the metal are discussed. 相似文献