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Teck Ming Koh Sie Tiong Ha Teck Leong Lee Siew Ling Lee Guan Yeow Yeap Hong Cheu Lin Ramesh T.Subramaniam 《中国化学快报》2011,22(5):619-622
The design and synthesis of new calamitic benzothiazole-based liquid crystals,2-[4-(4-alkyloxybenzoyloxy)-phenyl]ben-zothiazoles are presented.The target compound was characterized using spectroscopic techniques,such as FT-IR,NMR(1H and 13C),microanalysis and EI-MS.The liquid crystalline behaviours of these compounds were thoroughly examined by differential scanning calorimetry and polarizing optical microscope techniques.These materials exhibited enantiotropic nematic phase with high thermal stability(>168℃).Smectic A phase starts to emerge as monotropic(metastable) phase from C10 member and changes into enantiotropic(stable) phase from C12 and persists up to C16 members. 相似文献
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Pierre Wolf Ramesh Balakrishnan Gabriel Staffelbach Laurent Y. M. Gicquel Thierry Poinsot 《Flow, Turbulence and Combustion》2012,88(1-2):191-206
Great prominence is put on the design of aeronautical gas turbines due to increasingly stringent regulations and the need to tackle rising fuel prices. This drive towards innovation has resulted sometimes in new concepts being prone to combustion instabilities. In the particular field of annular combustion chambers, these instabilities often take the form of azimuthal modes. To predict these modes, one must compute the full combustion chamber, which remained out of reach until very recently and the development of massively parallel computers. Since one of the most limiting factors in performing Large Eddy Simulation (LES) of real combustors is estimating the adequate grid, the effects of mesh resolution are investigated by computing full annular LES of a realistic helicopter combustion chamber on three grids, respectively made of 38, 93 and 336 million elements. Results are compared in terms of mean and fluctuating fields. LES captures self-established azimuthal modes. The presence and structure of the modes is discussed. This study therefore highlights the potential of LES for studying combustion instabilities in annular gas turbine combustors. 相似文献
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Nageswara Rao Pilli Jaswanth Kumar Inamadugu Ramesh Mullangi Vijaya Kumari Karra Jayathirtha Rao Vaidya J. V. L. N. Seshagiri Rao 《Biomedical chromatography : BMC》2011,25(4):439-449
A rapid, simple, sensitive and specific LC‐MS/MS method has been developed and validated for the simultaneous estimation of atorvastatin (ATO), amlodipine (AML), ramipril (RAM) and benazepril (BEN) using nevirapine as an internal standard (IS). The API‐4000 LC‐MS/MS was operated under the multiple‐reaction monitoring mode using electrospray ionization. Analytes and IS were extracted from plasma by simple liquid–liquid extraction technique using ethyl acetate. The reconstituted samples were chromatographed on C18 column by pumping 0.1% formic acid–acetonitrile (15:85, v/v) at a flow rate of 1 mL/min. A detailed validation of the method was performed as per the FDA guidelines and the standard curves were found to be linear in the range of 0.26–210 ng/mL for ATO; 0.05–20.5 ng/mL for AML; 0.25–208 ng/mL for RAM and 0.74–607 ng/mL for BEN with mean correlation coefficient of ≥0.99 for each analyte. The intra‐day and inter‐day precision and accuracy results were well with in the acceptable limits. A run time of 2.5 min for each sample made it possible to analyze more than 400 human plasma samples per day. The developed assay method was successfully applied to a pharmacokinetic study in human male volunteers. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Raja Reddy Kallem Jaswanth Kumar Inamadugu Mullangi Ramesh J. V. L. N. Seshagirirao 《Biomedical chromatography : BMC》2013,27(3):349-355
A rapid, simple, sensitive and selective LC‐MS/MS method has been developed and validated for quantification of nifedipine (NF) and atenolol (AT) in human plasma (250 μL). The analytical procedure involves a one‐step liquid–liquid extraction method using carbamazepine as an internal standard (IS). The chromatographic resolution was achieved on a Hypurity Advance C18 column using an isocratic mobile phase consisting of 5 mm ammonium acetate–acetonitrile (15:85, v/v) at flow rate of 1.0 mL/min. The LC‐MS/MS was operated under the multiple‐reaction monitoring mode using electrospray ionization. The total run time of analysis was 2 min and elution of NF, AT and IS occurred at 0.79, 1.04 and 0.76 min, respectively. A detailed method validation was performed as per the FDA guidelines and the standard curves found to be linear in the range of 1.02–101 ng/mL for NF and 5.05–503 ng/mL for AT, with a coefficient of correlation of ≥0.99 for both the drugs. NF and AT were found to be stable in a battery of stability studies, viz. bench‐top, auto‐sampler and repeated freeze–thaw cycles. The validated assay method was successfully applied to a pharmacokinetic study in humans. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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