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1.
Two binary mixtures of polar liquid crystal materials were previously reported to exhibit three incommensurate smectic A phases predicted for such materials on the basis of phenomenological theory. Results of our recent high-resolution X-ray scattering experiments show that no incommensurate phases exist in the two systems. Wide coexistence regions are found at first order transitions between various frustrated smectic phases of these mixtures. These regions were previously identified as the incommensurate smectic A phases. The phase diagrams of the two systems determined with high-resolution X-ray technique are shown to be in excellent agreement with Baroisa-Prost-Lubensky theory. 相似文献
2.
Satyendra Nath Gupta Uma Sankar Nandi 《Journal of polymer science. Part A, Polymer chemistry》1970,8(6):1493-1501
Dimethyl sulfoxide has been used as a solvent in the polymerization of methyl methacrylate and styrene. The chain-transfer coefficients of the solvent and the values of δ [i.e., (2kt)1/2/kp] in solvent-monomer mixtures of various compositions were determined. δ was observed to be dependent on the solvent concentration in the case of methyl methacrylate but remained constant in case of styrene. The lowering of the values of δ with increasing solvent concentration in case of methyl methacrylate has been attributed to an interaction between the solvent and poly(methyl methacrylate) radical resulting in lower termination rate. 相似文献
3.
Pradip K. Bhowmik Haesook Han Ivan K. Ndedeltchev James J. Cebe Shin‐Woong Kang Satyendra Kumar 《Liquid crystals》2013,40(8):891-906
Several viologen bis{tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate} salts were prepared by metathesis reaction of the corresponding viologen dibromides (diiodide) with sodium bis{tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate} salt in a polar organic solvent. They were characterized for their physical and thermal properties by experimental techniques including variable temperature X‐ray diffraction. All exhibited low T g and T m, and their T g/T m (K) ratios were in the range 0.66–0.79. Several exhibited polymorphism and formed isotropic ionic melts at <150°C. They were soluble in many common organic solvents such as ethers, alcohols, acetonitrile and methylene chloride. They exhibited photoluminescence in both 1,2‐dimethoxyethane and methanol, as well as in the solid state. In the solid state, the emission spectra exhibited hypsochromic shift when compared with those in solutions of 1,2‐dimethoxyethane and methanol. 相似文献
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Nitin Mehrotra Sreedharan Sabarinath Satyendra Suryawanshi Kanwal Raj Ram Chandra Gupta 《Chromatographia》2009,69(9-10):1077-1082
The herbal medicament derived from the lipid soluble fraction obtained from Curcuma longa L. (Zingiberaceae) has shown potential neuroprotective activity in disorders like stroke. HM has been standardized with three biomarkers: ar-turmerone, α/β-turmerone and curlone, major bisabolane sesquiterpenes of turmeric oil. Development of a biaonalytical method for these sesquiterpenes was initiated to characterize its preclinical pharmacokinetics in rabbits to accelerate its development as a potential candidate for vascular complications. Since, the compounds are structurally and chemically very similar, gradient elution was utilized on a C-18 reversed phase column with a mobile phase comprising of acetonitrile and deionised water. The UV detector was set at wavelengths 240 and 270 nm. The sample clean-up was performed by protein precipitation with acetonitrile. The method was reasonably sensitive with limits of quantitation (LOQ) of 0.098 μg mL?1 in plasma for all the analytes. Accuracy and precision were within the acceptable limits, as indicated by relative standard deviation (% RSD) varying from 1.3 to 13.6% and bias values ranging from ?5.5 to 10.3%, respectively. Moreover, the analytes were stable in plasma even after three freeze-thaw cycles. The method was applied to generate preliminary pharmacokinetics of turmeric oil in rabbits after intravenous administration. 相似文献
7.
Satyendra Ray 《Colloid and polymer science》1928,45(1):9-12
Ohne Zusammenfassung
Uebersetzt von Alexander Naumann (Leipzig). 相似文献
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A novel, efficient and protecting group free enantioselective synthetic approach of (?)-(R)-1 and (+)-(S)-rolipram 2 is described employing the organocatalyzed asymmetric Michael addition, Henry condensation, Wittig olefination and reductive lactamization reactions as key steps. 相似文献
10.
F. J. Arcelus Satyendra Kumar G. Srinivasan 《4OR: A Quarterly Journal of Operations Research》2011,9(3):279-297
The saliency of returns in today’s business world is unquestionable, in such items as toys, Christmas decorations, books,
seasonal/fashion items and the like. This is largely due to the high economic benefits prevalent in some industries today
and to the increasing opportunities for resale in secondary and global markets. This paper attempts to model the profitability
of returns policy in presence of a secondary market, to a profit-maximizing manufacturer in a newsvendor framework. The returns
policy applies both for the unsold merchandise left at the end of the selling season and the items returned by the unsatisfied
customers within the specified time period. With a returns policy, the manufacturer shares the risks of demand uncertainty,
in turn assuaged by the availability of secondary market. The manufacturer’s decision is to arrive at an optimal wholesale
price and the returns policy, based on the retailer’s reaction on that offer. The retailer in turn optimizes the retail price
and the order quantity to meet a price-dependent uncertain demand. This set of optimal policies has then been contrasted to
that obtained from maximizing the combined profit of the manufacturer and of the retailer. The key question in the comparison
has been clearly answered. The total combined profit that coordinates the policies of both channels exceeds that of the sum
of the profits obtained independently. 相似文献