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131.
Maddali L.N. Rao Varadhachari Venkatesh Priyabrata Dasgupta 《Tetrahedron letters》2010,51(38):4975-4980
Oxalyl chloride has been demonstrated to function as C1 carbonyl synthon in the carbonylations of triarylbismuth and triarylindium nucleophiles under palladium-catalyzed conditions. All the three aryl groups from both bismuth and indium reagents participated in carbonylative couplings to afford the corresponding functionalized ketones in high yields. This study also disclosed a novel utilization of oxalyl chloride as facile alternative source of CO for carbonylations under palladium catalysis. 相似文献
132.
Kerry-Ann Green Paul T. Maragh Kamaluddin Abdur-Rashid Alan J. Lough Tara P. Dasgupta 《Tetrahedron letters》2014
The synthesis of a series of imidazolinium chlorides containing the [2.2]paracyclophane scaffold is described. Attempts to deprotonate the salts with strong bases resulted in hydrolytic ring-opening and yielded N-formylethylenediamine products rather than the intended free carbenes. 相似文献
133.
134.
Photonic crystals fabricated from the colloidal spheres of polymethyl methacrylate (PMMA) using the inward-growing self-assembly
technique were subsequently in-filled with zinc oxide (ZnO) prepared by the sol-gel process. The polymer template was removed
by heat treatment and chemical method to get ZnO-inverse photonic crystal. The structural quality of the inverse photonic
crystal obtained by the chemical method was found to be superior to that obtained by heat treatment. The ZnO-inverse photonic
crystal obtained by the chemical method was further treated at an elevated temperature to ensure the crystalline nature of
ZnO. Laser-induced emission studies on ZnO-inverse photonic crystals were carried out at an excitation wavelength of 325 nm.
The emission spectra showing UV and visible bands at collection angle of 45° from the direction of excitation helped to establish
the role of crystalline ZnO. 相似文献
135.
A time-dependent, two-dimensional (in space) rate equation model of a transversely-pumped pulsed dye laser oscillator, which
incorporates transverse pump intensity variation in the presence of intracavity dye laser radiation, is proposed to understand
and predict its temporal behaviour. The model yields output pulses which agree well with experimental results using rhodamine
6G and kiton red dyes. The shape, amplitude and temporal position of the simulated pulse within the pump pulse vary dramatically
across the tuning range of each dye depending on the relative gain and loss values. 相似文献
136.
Many aspects of photophysical, photostability and laser properties of kiton red S dye remain unresolved, particularly for
pumping with 578 nm radiation of CVL and 532 nm output of Nd:YAG lasers, and these are studied using different alcohol- and
water-based binary solvents. Our results show that methanol is better suited for low and high-repetition-rate KRS dye lasers
because of its superior laser efficiency, photostability as well as photothermal properties. 相似文献
137.
Summary: Self assembly of oligo(phenylene vinylene) based gelator is studied in three different solvents namely, trans-decahydronaphthalene (trans-decalin), benzene and benzyl alcohol. The morphology as well as the thermal properties are different for benzyl alcohol gel as compared to those gels in trans-decalin or benzene. X-ray diffraction studies indicate that in case of benzyl alcohol gel, the molecular organization is highly ordered with respect to the fibrils grown in other two solvents. 相似文献
138.
139.
There has been no reliable published data on the presence of perchlorate in seawater. Seaweeds are among the most important plant life in the ocean and are good sources of iodine and have been widely used as food and nutritional supplement. Perchlorate is known to inhibit the transport of iodide by the sodium iodide symporter (NIS), present e.g., in the thyroid and mammary glands. With perchlorate being increasingly detected in drinking water, milk and various other foods, increasing the iodide intake through inexpensive natural supplements may be an attractive solution for maintaining iodine assimilation. We report here measurable concentrations of perchlorate in several samples of seawater (detectable in about half the samples analyzed). We also report the iodide and perchlorate concentrations of 11 different species of seaweed and the corresponding bioconcentration factors (BCF) for perchlorate and iodide, relative to the seawater from which they were harvested. All seaweed samples came from the same region, off the coast of Northeastern Maine. Concentrations of iodide and perchlorate in four seawater samples collected from the region near harvest time were 30 ± 11 and 0.16 ± 0.084 μg l−1, respectively. Concentrations of both iodide and perchlorate varied over a wide range for different seaweed species; iodide ranging from 16 to 3134 mg kg−1 and perchlorate from 0.077 to 3.2 mg kg−1. The Laminaria species had the highest iodide concentration; Laminaria digitata is the seaweed species most commonly used in the kelp tablets sold in health food stores. Our sample of L. digitata contained 3134 ± 15 mg iodide/kg dry weight. The BCF varied widely for different species, with Laminaria species concentrating iodide preferentially over perchlorate. The iodide BCF (BCFi) to perchlorate BCF (BCFp) quotient ranged from 0.66 to 53; L. digitata and L. saccarina having a BCFi/BCFp value of 45 and 53, respectively, far greater than a simple anion exchange process will allow. Although most seaweed samples contain some amount of perchlorate, the great majority contains iodide in so much higher amount that at least for the commonly used Laminaria species, the iodide/perchlorate ratio is greater than the square of the perchlorate to iodide selectivity factor reported for the mammalian NIS and should thus lead to net beneficial iodine nutrition even in a two-stage mother-infant scenario. 相似文献
140.
In this paper we investigate to what extent the results of Z. Wang and D. Daigle on “nice derivations” of the polynomial ring over a field k of characteristic zero extend to the polynomial ring over a PID R, containing the field of rational numbers. One of our results shows that the kernel of a nice derivation on of rank at most three is a polynomial ring over k. 相似文献