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21.
Some new coordination polymers have been synthesized by combining adipyl bis-biuret and azelyl bis-biuret with metals of first transition series viz Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). They were characterized by elemental analysis, infrared and reflectance spectral and magnetic studies. A detailed thermal study was carried out and thermal stability compared. The results obtained have been discussed.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
22.
Estimation of <Superscript>90</Superscript>Sr activity in reprocessed uranium from the PUREX process
S. Ravi A. K. Deepa B. Surekha S. Susheela P. V. Achuthan S. Anil Kumar K. Vijayan U. Jambunathan S. K. Munshi P. K. Dey 《Journal of Radioanalytical and Nuclear Chemistry》2007,272(1):123-126
90Sr estimation in reprocessed uranium was carried out by a series of solvent extraction and carrier precipitation techniques
using strontium and lanthanum carriers. Fuming with HClO4 was used to remove 106Ru as RuO4. Three step solvent extraction with 50% tri-n-butyl phosphate in xylene in presence of small amounts of dibutyl phosphate
and thenoyl trifluoro acetone was carried out to eliminate uranium, plutonium, thorium and protactinium impurities. Lanthanum
oxalate precipitation in acid medium was employed to scavenge the remaining multivalent ions. Strontium was precipitated as
strontium oxalate in alkaline pH and 137 Cs was removed by washing the precipitate with water. A strontium recovery well above 70% was obtained. Final estimation
was carried out by radiometry using end window GM counter after drying the precipitate under an infra red lamp. The same procedure
was extended to the estimation of 90Sr in a diluted sample of the actual spent fuel solution. An additional lanthanum oxalate precipitation step was required
to remove the entire 144Ce impurity from this sample. This modified procedure was employed in the determination of 90Sr in a number of reprocessed uranium samples and the over all precision of the method was found to be well within ±10%. An
additional barium chromate precipitation step was necessary for the analysis of reprocessed uranium samples from high bumup
fuels to eliminate trace amounts of short lived 224Ra produced during the decay of 232U and its daughters as they interfere in the estimation of 90Sr. 相似文献
23.
The chelation reactions of gallium and indium with Arsenazo 1, i.e., 3-[(o-arsonophenyl)azo]-4,5-dihydroxy-2,7-naphthalene disulfonic acid, have been studied in detail. The nature and number of complexes formed was studied and it was found that gallium and indium form only one complex with Arsenazo 1. The composition of the complexes formed was found by various methods and it was found that both the complexes have composition 1:1 (metal:reagent). The values of log K were calculated by different methods at four different fixed values of ionic strength. For both the complexes, the value of thermodynamic stability constant has been obtained by plotting values of log K against ionic strength and extrapolating the curves to zero ionic strength. A tentative suggestion about the structure of the chelate ring has been made. The studies were further extended to the analytical aspects of the complexes and a suitable procedure has been recommended for the spectrophotometric determination of gallium and indium using this reagent. 相似文献
24.
Haresh S. Kalasariya Nikunj B. Patel Akanksha Yadav Kahkashan Perveen Virendra Kumar Yadav Faris M. Munshi Krishna Kumar Yadav Shamshad Alam You-Kyung Jung Byong-Hun Jeon 《Molecules (Basel, Switzerland)》2021,26(24)
Cosmetic industries are highly committed to finding natural sources of functional active constituents preferable to safer materials to meet consumers’ demands. Marine macroalgae have diversified bioactive constituents and possess potential benefits in beauty care products. Hence, the present study was carried out to characterize the biochemical profile of marine macroalga Chaetomorpha crassa by using different techniques for revealing its cosmetic potentials. In results, the FTIR study characterized the presence of different bioactive functional groups that are responsible for many skin-beneficial compounds whereas six and fifteen different important phycocompounds were found in GCMS analysis of ethanolic and methanolic extracts, respectively. In the saccharide profile of C. crassa, a total of eight different carbohydrate derivatives were determined by the HRLCMS Q-TOF technique, which showed wide varieties of cosmetic interest. In ICP AES analysis, Si was found to be highest whereas Cu was found to be lowest among other elements. A total of twenty-one amino acids were measured by the HRLCMS-QTOF technique, which revealed the highest amount of the amino acid, Aspartic acid (1207.45 nmol/mL) and tyrosine (106.77 nmol/mL) was found to be the lowest in amount among other amino acids. Their cosmetic potentials have been studied based on previous research studies. The incorporation of seaweed-based bioactive components in cosmetics has been extensively growing due to its skin health-promoting effects. 相似文献
25.
The liquid–metal magneto-hydrodynamic (LMMHD) facility at the Bhabha Atomic Research Centre (Mumbai) has a two-phase mercury–nitrogen
flow system which is currently used for various studies related to void-fraction, flow, pressure, slip-ratio, of the flow
system. Non-invasive measurements of steady-state void-fraction profiles has been carried out by a 60 mCi Cesium-137 gamma-ray
source and a NaI(Tl) detector mounted on a trolley. The reconstructed cross-sectional void-fraction profiles were in the riser
section of the LMMHD loop, and in this process radial tomographic methods were used, e.g. least-squares and chord-segment-inversion
(CSI). The present work investigates the possible uncertainties in the profiles thus measured. A simple statistical model
has been developed for the CSI algorithm due to the inherent “square nature” of the data matrix. The inherent Poisson error
has been also investigated in this exercise.
Received: 1 December 1997/Accepted: 30 May 1998 相似文献
26.
The ignition delay time of two stoichiometric methane/hydrogen/air mixtures has been measured in a shock tube facility at pressures from 16 to 40 atm and temperatures from 1000 to 1300 K. Overall, the observed reduction in ignition delay with some methane replaced by hydrogen is relatively small given the large concentration of hydrogen involved in the current study. With a high hydrogen mole fraction (35% of the total fuel), a reduction of the ignition‐promoting effect was observed with reduced temperature. A detailed chemical kinetic mechanism was used to simulate ignitions of test mixtures behind reflected shocks. An analysis of the mechanism indicates that at higher temperatures, the rapid decomposition of hydrogen molecules leads to a quick formation of H radical pools, which promote the chain branching through H + O2 ? O + OH. At lower temperatures, the branching efficiency of hydrogen is low; a weak effect of hydrogen on methane ignition could be result from the reaction between H2 and methylperoxy CH3O2, which contributes extra H radicals to the reaction system. The effects of hydrogen also decrease with increasing pressure; this is related to the negative pressure dependence of hydrogen at the second ignition limit. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 221–233, 2006 相似文献
27.
Based on general arguments, the in-medium quark propagator in a quark-gluon plasma leads to a quark dispersion relation consisting
of two branches, of which one exhibits a minimum at some finite momentum. This results in a vanishing group velocity for collective
quark modes. Important quantities such as the production rate of low mass lepton pairs and mesonic correlators depend inversely
on this group velocity. Therefore these quantities, which follow from self energy diagrams containing a quark loop, are strongly
affected by van Hove singularities (peaks and gaps). If these sharp structures could be observed in relativistic heavy-ion
collisions it would reveal the physical picture of the quark-gluon plasma (QGP) as a gas of quasiparticles. 相似文献
28.
29.
S. C. Tripathi R. Kannan P. S. Dhami P. W. Naik S. K. Munshi P. K. Dey N. A. Salvi S. Chattopadhyay 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(3):691-695
The improvement and the refinement of non-viable Rhizopus arrhizus biomass were investigated via immobilization. Immobilization was carried out by using sodium alginate/CaCl2 solution and formaldehyde/HCl cross-linking with dead Rhizopus arrhizus biomass and were used for the sorption of radionuclides from low level effluent wastes. The sodium alginate/CaCl2 immobilized biomass (ratio 1:2) showed about 86% sorption for 241Am activity but due to its soft nature and tendency to undergo distortion in shape, is unsuitable for practical applications.
The biomass cross-linked with 15% formaldehyde/0.1 M HCl solution has a relatively high mechanical strength and rigidity.
It was showing a sorption of >99% for 241Am activity and has the sorption capacity of ~65 mg/g for americium and uranium. Hence, it can be utilized for the removal
of radionuclides from radioactive waste effluents. 相似文献
30.
Sayan Sarkar Dr. Piyali Sarkar Sandip Munshi Prof. Pradyut Ghosh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(25):7307-7314
Selectivity of aryl iodo over ethynyl iodo toward the Suzuki cross coupling reaction is explored by utilizing a palladium complex of amino-ether heteroditopic macrobicycle. Subsequently, unreacted ethynyl iodide undergoes homocoupling reaction in the same catalytic atmosphere, thereby representing a cascade dual C−C coupling reaction. Furthermore, this approach is extended for novel one-pot synthesis of unsymmetrical 1,3-diynes. 相似文献