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61.
Amrita Chakraborty Samiran Kar D N Nath Nikhil Guchhait 《Journal of Chemical Sciences》2007,119(2):195-204
Photoinduced intramolecular charge-transfer reactions in 4-amino-3-methyl benzoic acid methyl ester (AMBME) have been investigated
spectroscopically. AMBME, with its weak charge donor primary amino group, shows dual emission in polar solvents. Absorption
and emission measurements in the condensed phase support the premise that the short wavelength emission band corresponds to
local emission and the long wavelength emission band to the charge transfer emission. Laser-induced fluorescence excitation
spectra show the presence of two low-energy conformers in jet-cooled molecular beams. Theoretical calculations using density
functional theory help to determine structure, vibrational modes, potential energy surface, transition energy and oscillator
strength for correlating experimental findings with theoretical results. 相似文献
62.
Anjan Biswas Abhijit Bandyopadhyay Nikhil K. Singha Anil K. Bhowmick 《Journal of polymer science. Part A, Polymer chemistry》2007,45(23):5529-5540
In this investigation, solution grafting of acrylic acid (AA) in presence of benzoyl peroxide (BPO) was carried out onto metallocene‐based “poly(ethylene‐octene) elastomers” (POE) as well as “poly(ethylene‐butene) elastomers” (PBE), to impart polarity on the non‐polar rubbery matrix and also to study the effects of crystallinity and pendant chain length on the “grafting percentage” and “percent gel yield” at optimized conditions for all the POE and PBE systems. Reaction parameters were optimized on the basis of the relative proportions of graft and gel formations obtained through %weight gain, Fourier Transform infrared spectroscopy and elemental analysis. The effect of grafting at its maximum level on various physico‐mechanical properties was also thoroughly investigated by using X‐ray diffraction (XRD), differential scanning calorimetry (DSC), mechanical, dynamic mechanical (DMTA), and thermogravimetric analysis (TGA) and the properties were correlated with the structure of the modified polymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5529–5540, 2007 相似文献
63.
Mathematical Programming - In this paper, we bound the integrality gap and the approximation ratio for maximum plane multiflow problems and deduce bounds on the flow-multicut-gap. We consider... 相似文献
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66.
We report the application of aluminum doped ZnO (ZnO:Al) layer as a buffer on ITO glass for fabrication of non-inverted polymer solar cells. The ZnO:Al thin film was deposited using DC magnetron sputtering, with the thickness being varied from 23 to 100 nm. The devices showed most discernible improvements in their efficiencies when a thin layer of ZnO:Al film of thickness ∼40 nm was introduced. The observed enhancement in short circuit current density and open circuit voltage is likely attributed to the role of the ZnO:Al film as an optical tuner and an interfacial diffusion barrier. The result suggests that a metal oxide layer inserted between ITO and polymer layers can be a route for improving both efficiency and stability of polymer solar cells. 相似文献
67.
Gas chromatographic (GC) profiles of cuticular hydrocarbon extracts obtained from individual and pooled ant samples were analyzed using pattern recognition techniques. Clustering according to the biological variables of social caste and colony were observed. Pooling individual extracts enhanced the recognition of patterns in the GC profile data characteristic of colony. Evidently, the contribution of the ant's individual pattern to the overall hydrocarbon profile pattern can obscure information about colony in the GC traces of cuticular hydrocarbon extracts obtained from red fire ants. Re-analysis of temporal caste and time period data on the cuticular hydrocarbon patterns demonstrates that sampling time and social caste must be taken into account to avoid unnecessary variability and possible confounding. This and the fact that foragers could not be separated from reserves and brood-tenders in all five laboratory colonies studied suggests that cuticular hydrocarbons as a class of sociochemicals cannot model every facet of nestmate recognition in Solenopsis invicta which in turn suggests a potential role for other compounds in the discrimination of alien conspecifics from nestmates. 相似文献
68.
Biswanath Das Nikhil Chowdhury Kongara Damodar Bommena Ravikanth 《Helvetica chimica acta》2007,90(10):2037-2040
A new and convenient stereoselective synthesis of (Z)‐2‐(chloromethyl)alk‐2‐enoates has been achieved from Baylis–Hillman adducts by treatment with PPh3/Cl3CCONH2 at room temperature. The synthesis can proceed under mild and acid‐free conditions to form the products in high yields. 相似文献
69.
[reaction: see text]. Diprotected monosubstituted hydrazine derivatives have been prepared via the reaction of tert-butyl carbazates with boronic acids catalyzed by cuprous chloride at room temperature. 相似文献
70.
Jana NR 《Chemical communications (Cambridge, England)》2003,(15):1950-1951
High quality single size nanorods can be separated from polydisperse samples using surfactant-assisted nanorod self-assembly. 相似文献