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311.
Raghvendra Singh Yadav Shiv Kumar Pandey Avinash Chandra Pandey 《Journal of luminescence》2011,131(9):1998-1893
Nanostructured BaAl12O19:Mn2+ phosphor particles of nano-rod morphology with diameter 40-100 nm and length up to 200-600 nm has been synthesized by solution combustion method and its photoluminescence characteristics have been studied by Vacuum Ultra-Violet Photoluminescence spectrometer (VUVPL) under 147 nm excitation. The crystallographic phase purity of BaAl12O19:Mn2+ nanostructured phosphor particle synthesized by solution combustion approach is confirmed by X-ray diffraction (XRD). The broadening of XRD diffraction peaks indicates nanocrystalline nature of particles present in powder. The emission spectrum of BaAl12O19:Mn2+ nanophosphor on 147 nm excitation consists of a wide green band with a peak at about 515 nm, which is due to a 3d5 (4T1g)-3d5 (6A1g) transition corresponds of Mn2+ ions. It is found that the concentration quenching is obtained when Mn2+ content (x) is 0.05 in BaAl12O19:xMn2+ nanophosphor on 147 nm excitation. The decay time of 3d5 (4T1 g)-3d5 (6A1 g) transition of Mn2+ ions at 147 nm excitation is about 23 ms for BaAl12O19:Mn2+ nanophosphor. This nanostructured green emitting BaAl12O19:Mn2+ phosphor can find potential application in Plasma Display Panels (PDPs) and mercury-free fluorescent lamps. 相似文献
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313.
A highly efficient method for the deacetylation of thioacetate is reported under mild acidic conditions employing acetyl chloride in methanol. Some of the major advantages are mild conditions, high efficiency, high yields, and easy operations. 相似文献
314.
Baji Shaik Ji Hee Park Tae Kyu An Young Ri Noh Soon Byung Yoon Chan Eon Park Young Jin Yoon Yun-Hi Kim Sang-Gyeong Lee 《Tetrahedron》2013
Anthracene and thiophene compounds are promising materials for OTFTs. We report here, the synthesis, as well as the physical, thermal, and optoelectronic properties of alkyl-substituted asymmetric anthracene–thiophene compounds connected by a bridged triple bond. The target molecules were synthesized using 2-bromoanthracene as the starting material, and the proceeding reactions included alkylation, bromination, and the Sonogashira coupling reaction. The synthesized compounds were both thermally and electrochemically stable. Among the synthesized compounds, HTEA (7a) and DTEA (7b) showed mobility and on/off ratio values of 1.3×10−1 cm2/V s, 2.6×106 and 2.0×10−2 cm2/V s, 1.0×106, respectively. 相似文献
315.
Glucose stabilized palladium nanoparticles (PdNPs) have been prepared and the application of NPs in catalyzing both Suzuki and Heck reactions has been explored in aqueous media under microwave conditions. Both electron-rich and electron-deficient aryl halides can be coupled with a variety of boronic acids and styrene to access a wide variety of biaryl compounds and substituted alkenes in good to excellent yields. The catalyst can be recycled and reused four times with minimally affecting the morphology and efficiency of the nanoparticles. A plausible reaction mechanism has been proposed. 相似文献
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317.
Synthesis and properties of thioether spacer containing gemini imidazolium surfactants 总被引:1,自引:0,他引:1
Twelve new gemini imidazolium surfactants have been synthesized, having dodecyl, tetradecyl, hexadecyl, and octadecyl chain lengths and three different spacers (i.e., -S-(CH(2))(n)-S-), where n = 2, 3, and 4 and their surface properties have been evaluated by surface tension and conductivity methods. The thermal degradation of these new gemini surfactants was determined by thermogravimetric analysis (TGA). These surfactants have low cmc values as compared to other categories of gemini cationic surfactants and exhibit peculiarities at sufficiently low concentration because they were able to form premicellar aggregates over a wide range of concentration below their cmc values. The DNA binding affinity of these gemini surfactants determined by agarose gel electrophoresis and ethidium bromide exclusion experiments established their strong interaction with DNA, thereby protecting it against enzymatic degradation. 相似文献
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319.
Avinash Khare 《Pramana》1997,49(1):41-64
In the past ten years, the ideas of supersymmetry have been profitably applied to many nonrelativistic quantum mechanical problems. In particular, there is now a much deeper understanding of why certain potentials are analytically solvable. In this lecture I review the theoretical formulation of supersymmetric quantum mechanics and discuss many of its applications. I show that the well-known exactly solvable potentials can be understood in terms of a few basic ideas which include supersymmetric partner potentials and shape invariance. The connection between inverse scattering, isospectral potentials and supersymmetric quantum mechanics is discussed and multi-soliton solutions of the KdV equation are constructed. Further, it is pointed out that the connection between the solutions of the Dirac equation and the Schrödinger equation is exactly same as between the solutions of the MKdV and the KdV equations. 相似文献