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101.
An efficient synthesis of -dibenzylbutyrolactones, applicable to very many of those lignans, is outlined. Two examples including di-O-methyl compound X (HPMF) are given. 相似文献
102.
103.
[reaction: see text] The first enantioselective total synthesis of valeriananoids A-C (-)-1-3 is reported starting from the readily available monoterpene (R)-carvone, employing a tandem intermolecular Michael addition-intramolecular Michael addition-alkylation sequence and an electron-transfer-mediated 6-endo-trig cyclization as key steps. 相似文献
104.
Gopal C Bhar Pathik Kumbhakar D V Satyanarayana N S N Banerjee U Nundy C G Chao 《Pramana》2000,55(3):405-412
Generation of third harmonic of CO2 laser radiation has been obtained in a type-II, ϑ=57° cut 9 mm thick AgGaSe2 crystal for the first time by sum-frequency-mixing of the fundamental with its second harmonic, the latter being obtained
using another type-I, ϑ=55° cut 11 mm thick AgGaSe2 crystal. The energy conversion efficiencies obtained for second harmonic and third harmonic generations are 6.3% and 2.4%
respectively with the input fundamental pump power density of 5.9 MW/cm2 only. The wavelength of the fundamental CO2 laser radiation used for the generation of harmonics is 10.6 μm, P(20) line. A compact TEA CO2 laser source has been built in the laboratory. 相似文献
105.
We study asymptotic behavior of solutions to an initial value problem posed for heat equation. For which, we construct an approximate solution to the initial value problem in terms of derivatives of Gaussian by incorporating the moments of initial function. Spatial shifts are introduced into the leading order term as well as penultimate term of the approximation. This paper is continuation to the work of Yanagisawa [14]. 相似文献
106.
P. Ramesh Kumar M. Venkateswarlu Manjusri Misra Amar K. Mohanty N. Satyanarayana 《Ionics》2013,19(3):461-469
Lithium manganese phosphate (LiMnPO4) nanorods were synthesized using the modified polyol method. Polyvinylpyrrolidone was used as a stabilizer to control the shape and size of LiMnPO4 nanorods. Resin coating process was used to coat the carbon over the LiMnPO4 nanorods. X-ray diffraction and Fourier transform infrared spectroscopy results showed the formation of LiMnPO4 crystalline phase. The TEM image shows a uniform coating of the nano size (2.3 nm) carbon over the surface of LiMnPO4 nanorods and the EDS spectrum of the carbon-coated LiMnPO4 nanorods confirming the presence of carbon element along with the other Mn, P, and O elements. Impedance measurements were made on pure and carbon-coated LiMnPO4 nanorods, and their conductivities were evaluated by analyzing the measured impedance data using the WinFIT software. More than two orders of magnitude of conductivity enhancement was observed in the carbon-coated LiMnPO4 nanorods compared to pure ones, and the conductivity enhancement may be attributed to the presence of carbon over LiMnPO4 nanorods. Temperature dependence of conductivity and ac conductivity were calculated using impedance data of pure and carbon-coated LiMnPO4 nanorods. CR2032 type lithium ion coin cells were fabricated using pure and carbon-coated LiMnPO4 nanorods and characterized by measuring charge–discharge cycles between 2.9 and 4.5 V at room temperature. More than 25 % of improved capacity was achieved in the carbon-coated LiMnPO4 nanorods when compared to pure ones synthesized using modified polyol and resin coating processes. 相似文献
107.
108.
Smeer Durani M. Krishnakumar K. Satyanarayana 《Journal of Radioanalytical and Nuclear Chemistry》2012,294(2):215-220
A simple, effective and low cost solid phase extraction procedure was standardized for the trace and ultra-trace level determination of rare earth impurities, such as, Ce, Dy, Sm, Gd, Eu, Er etc. which act as neutron poisons, in nuclear grade uranium oxide (U3O8?>?99.9% by weight). The method involves selective separation of these elements as their fluorides with the help of activated charcoal from major uranium matrix followed by determination by ICP-MS and high resolution ICP-OES. The residual uranium content of the solution was <10???g/mL. The recovery of REEs ranges from 85 to 105%. The method was validated with nuclear grade uranium oxide standards CRM-I to CRM-V (BARC, Mumbai, India) in addition to some synthetic standards. The RSD of the method was ±12% (n?=?3). 相似文献
109.
110.
A series of deoxycholic and cholic acid‐derived oligomers were synthesized and their ability to extract hydrophilic dye molecules of different structure, size, and functional groups into nonpolar media was studied. The structure of the dye and “dendritic effect” in the extraction process was examined using absorption spectroscopy and dynamic light scattering (DLS). The efficiency of structurally preorganized oligomers in the aggregation process was evaluated by 1‐anilinonaphthalene‐8‐sulfonic acid (ANS) fluorescence studies. The possible formation of globular structures for higher‐generation molecules was investigated by molecular modeling studies and the results were correlated with the anomaly observed in the extraction process with this molecule. The ability of these molecules for selective extraction of specific dyes from blended colors is also reported. 相似文献