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131.
K. Sudarshan R. Tripathi R. Acharya A. G. C. Nair A. V. R. Reddy A. Goswami 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(3):1075-1080
The k 0-based internal mono-standard prompt gamma-ray neutron activation analysis (IM-PGNAA) method was used for compositional analysis of a cement standard provided by the International Atomic Energy Agency as a part of inter-laboratory comparison exercise. The PGNAA was also applied to a local cement sample for comparison purpose. The concentration ratios of elements with respect Ca were determined using the internal mono-standard method. The concentration ratios were then converted to the absolute concentrations by determining concentration of Ca in the cement using relative method. Concentrations of 11 elements were determined in both sample and standard of cement. The results of cement standard are found to be in good agreement with the certified values. The uncertainties on the elemental concentrations were in the range of 5–10 %. 相似文献
132.
In this report, we are documenting the synthesis of peptide barbiturate through copper-catalyzed oxidation of peptide disulfide. Single disulfide-containing contryphans are used as models to access possibility of anchoring of barbituric acid (BRB) onto the peptide disulfide. Current method permits anchoring of two molecules of BRB onto the polypeptide and yield of peptide barbiturates varies from 59 to 84%. Formation of cysteine sulfenic acid (Cys-SOH) during oxidation of disulfide was confirmed using chemical probe of Cys-SOH dimedone. Mass spectrometric studies have confirmed the presence of cysteine barbiturate in anchored peptides. Based on the nature of reactive oxygen species involved in oxidation of peptide disulfide, possible mechanisms were proposed for anchoring of BRB onto the peptide disulfide through Cys-SOH. This is the first report on anchoring of two molecules of BRB onto the closely spaced cysteine residues of single polypeptide. 相似文献
133.
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135.
Shin-Woong Kang Young Eun Choi Byeong Hoon Lee Jun Hee Lee Sudarshan Kundu Heui-Seok Jin 《Liquid crystals》2013,40(4):552-557
In-plane field driven vertical alignment device using a liquid crystal with positive dielectric anisotropy has been studied. In the device, the distance between inter-digital electrodes needs to be increased to achieve higher transmittance; however, such a design results in an increase in operating voltage and slower response time. In this work, we use polymer stabilisation technique, which generates surface tilt angle other than 90o, to improve upon these drawbacks. As a result, the proposed device shows lower operating voltage and faster response time while keeping transmittance at the same level, compared to those prior to polymer stabilisation. 相似文献
136.
Supported by Canadian NSERC Grant A-5300 and Polish Scientific Grant 211399101. 相似文献
137.
138.
V. Sridhar D. Sudarshan Reddy N. Ravikumar Reddy S. Satyanarayana 《Journal of Chemical Sciences》2002,114(1):11-23
Equilibria and kinetics of the reaction of bromomethyl(aquo) cobaloxime with histamine, histidine, glycine and ethyl glycine
ester and iodomethyl(aquo) cobaloxime with cyanide, imidazole and substituted imidazoles were studied as a function ofpH at 25°C, 10 M ionic strength (KCl) by spectrophotometry technique. The rate of substitution of H2O varies with thepKa of the incoming ligand, thus establishing the existence of nucleophilic participation of the ligand in the transition state.
Dissociation kinetic reactions were also studied as a function ofpH. Binding and kinetic data were interpreted based on the basicity, steric crowd of the entering ligand and HSAB principle.
To compare the rate constants of the entering ligandspH independent second-order rate constants were calculated. 相似文献
139.
S. Chhillar R. Acharya S. Sodaye K. Sudarshan S. Santra R. K. Mishra C. P. Kaushik R. K. Choudhury P. K. Pujari 《Journal of Radioanalytical and Nuclear Chemistry》2012,294(1):115-119
Barium borosilicate glass (BaBSG) is proposed as a potential candidate for vitrification of nuclear waste generated from thoria based nuclear reactors. Along with fission products, activation products and many inactive chemicals, like fluorine in the form of HF are expected to be present in the dissolver solution with nuclear waste. As vitrification occurs at high temperature, it is important to quantify fluorine in BaBSG. Due to its complex matrix, most of the wet chemical and nuclear analytical methods encounter problems in the estimation of fluorine. Particle induced γ-ray emission (PIGE) method has been standardized for non-destructive determination of fluorine contents in BaBSG samples utilizing measurement of prompt gamma-rays from 19F (p, p’γ) 19F reaction. Experiments have been carried out with thick pellet targets prepared in cellulose matrix using 4 MeV proton beam from the folded tandem ion accelerator at BARC, Mumbai. For obtaining current normalized count rate of interest, beam current variation was monitored by the Rutherford backscattering spectrometry (RBS) method as well as by the in situ approach using an externally added element sensitive to PIGE. In this paper standardization of PIGE methods for F determination, validation of methods using synthetic samples, and application to BaBSG samples are reported. 相似文献
140.
Gregory T. Lee Sudarshan K. Sehgal Ernesto Spinelli 《Algebras and Representation Theory》2014,17(5):1597-1601
Let F be a field of characteristic p > 2 and G a nonabelian nilpotent group containing elements of order p. Write F G for the group ring. The conditions under which the unit group ??(F G) is solvable are known, but only a few results have been proved concerning its derived length. It has been established that if G is torsion, the minimum derived length is ?log2(p + 1)?, and this minimum occurs if and only if |G′| = p. In the present note, we show that the same holds if G has elements of infinite order. 相似文献