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941.
Synthesis of solid [Cr(nta)(H2O)2] 1, kinetics and equilibrium of ots reaction with pentane-2,4-dione (Hpd) to form [Cr(nta)(pd)]− 2 (H3nta is nitrilotriacetic acid), aquation of 2 into 1, and some related reactions have been described. Parallel proton-independent and inverse proton-dependent paths lead from 1 to 2. The [H+]−1 path arises from metal assisted deprotonation of HE, the enol form of Hpd. Aquation of 2 into 1 involves [Cr(Hnta)(pd)(H2O]+ 2H (Hnta is tridentate nta) in addition to 2. The nta comples 1 is considerably more labile and a weaker acid than [Cr(H2O)6]3+. 相似文献
942.
An easy method for the recovery of gold from lead-rich minerals has been developed. The gold is extracted with methyl isobutyl ketone from an aqua regia solution of the mineral, then stripped into aqueous medium by evaporating the solvent, and finally co-precipitated with lead sulphide. The gold is uniformly distributed in the lead sulphide. 相似文献
943.
S. N. Bhattacharyya D. Maldas V. K. Pandey 《Journal of polymer science. Part A, Polymer chemistry》1986,24(10):2507-2515
N-Vinyl carbazole methyl methacrylate, and the binary mixtures of these monomers were grafted onto cellulose acetate films by taking recourse to Co-60 simultaneous irradiation grafting technique. The effect of various parameters (e.g., solvents, radiation dose, compositions of the monomers, and concentration of the monomers) on the extent of grafting in unitary and binary systems were studied. The optimum conditions for grafting were evaluated. The sensitizing effect of one monomer in the presence of other in the binary system was identified. The relative molecular reactivity and reactivity ratios were computed and these were used in explaining sensitization and the effect of monomer compositions on the extent of grafting in the binary system. 相似文献
944.
Dinabandhu Pramanick Jyotish Sarkar Ramanath Bhattacharyya 《Journal of polymer science. Part A, Polymer chemistry》1988,26(2):573-581
The reaction of ?H radicals with a number of aliphatic amino acids has been studied by entrapping the resultant radicals as end groups of poly(methyl methacrylate) that have been detected and estimated by the sensitive dye partition technique. The rate constants of the reaction (in mol?1 L S?1) of 7 amino acids at 25°C and at pH 1.00 have been determined as 8.33 × 108 for glycine, 2.56 × 109 for β-alanine, 2.01 × 109 for β-alanine, 3.99 × 109 for 4-amino butyric acid, 7.56 × 109 for (1+) valine, 1.42 × 1010 for (1?) leucine, and 5.98 × 1010 for 6-amino caproic acid. Glycine, α-alanine, β-alanine, and 4-amino butyric acid produced radicals that underwent deamination and incorporated only carboxyl-bearing end groups in the polymer. The other amino acids, leucine, valine, and 6-amino caproic acid, produced at least two types of radicals, radicals that underwent deamination and those that remained intact, and incorporated in the polymer both carboxyl- and amine-bearing end groups but in different amounts. The latter type of radicals were about 29% from 6-amino caproic acid, 23% from leucine, and 18% from valine. The change of pH from 0.80 to 2.72 did not produce any significant change in the end group profile of the polymer obtained, indicating no appreciable change in the rate of the reaction of ?H radicals with the simplest amino acid glycine in the pH range studied. 相似文献
945.
P. K. Sinhamahapatra S. Sinhamahapatra S. K. Bhattacharyya 《Reaction Kinetics and Catalysis Letters》1977,6(3):281-286
The structures of bismuth tungstate catalysts with Bi/W ratios of 2/3, 1/1, 2/1 and 6/1 have been studied by X-ray diffraction. The presence of corner sharing W–O octahedra in the bulk of Bi/W=2/1 and 1/1 compositions has been established. The Bi/W=2/3 catalyst appears to contain edge-shared W–O octahedra whereas W in the Bi/W=6/1 sample form WO4 tetrahedra. An apparent correlation has been obtained between the structures of the catalysts and their activities in the oxidation and ammoxidation of propylene and 1-butene.
Bi/W, 23, 11, 21 61, . , W–O Bi/W=21 11. Bi/W=23 W–O , Bi/W=61 . 1-.相似文献
946.
A. S. Bhattacharyya S. K. Raj Parameshwar Kommu P. Prabhakar R. Praveen Kumar Neha Kumari Kumar Gaurav 《Surface and interface analysis : SIA》2016,48(12):1294-1298
Cu thin films were deposited on Si(111), glass, and quartz substrates by magnetron sputtering. X‐ray diffraction, SEM, and photoemission electron microscope studies were carried out to characterize the films. An influence of the nature of substrate on the Cu2O and CuO phases formed was observed. Copper silicide formation in case of silicon substrates aided in formation of Cu2O rather than CuO unlike glass and quartz substrates. Formation of nanocrystallites was observed by SEM and X‐ray diffraction. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
947.
Ritz variational calculation for the singly excited states of compressed two‐electron atoms
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Jayanta K. Saha Sukhamoy Bhattacharyya Tapan K. Mukherjee 《International journal of quantum chemistry》2016,116(23):1802-1813
A detailed analysis on the effect of spherical impenetrable confinement on the structural properties of two‐electron ions in states has been performed. The energy values of 1sns [ ] ( ) states of helium‐like ions ( ) are estimated within the framework of Ritz variational method using explicitly correlated Hylleraas‐type basis sets. The correlated wave functions used here are consistent with the finite boundary conditions due to spherical confinement. A comparative study between the singlet and triplet states originating from a particular electronic configuration shows incidental degeneracy and the subsequent level‐crossing phenomena. The thermodynamic pressure felt by the ion inside the sphere pushes the energy levels toward continuum. Critical pressures for the transition to strong confinement regime (where the singly excited two‐electron energy levels cross the corresponding one‐electron threshold) as well as for the complete destabilization are also estimated. 相似文献
948.
A Locally Correctable Code (LCC) is an error correcting code that has a probabilistic self-correcting algorithm that, with high probability, can correct any coordinate of the codeword by looking at only a few other coordinates, even if a δ fraction of the coordinates is corrupted. LCCs are a stronger form of LDCs (Locally Decodable Codes) which have received a lot of attention recently due to their many applications and surprising constructions.In this work, we show a separation between linear 2-query LDCs and LCCs over finite fields of prime order. Specifically, we prove a lower bound of the form p Ω(δd) on the length of linear 2-query LCCs over F p , that encode messages of length d. Our bound improves over the known bound of 2 Ω(δd) [8,10,6] which is tight for LDCs. Our proof makes use of tools from additive combinatorics which have played an important role in several recent results in theoretical computer science.We also obtain, as corollaries of our main theorem, new results in incidence geometry over finite fields. The first is an improvement to the Sylvester-Gallai theorem over finite fields [14] and the second is a new analog of Beck's theorem over finite fields.The paper also contains an appendix, written by Sergey Yekhanin, showing that there do exist nonlinear LCCs of size 2 O(d) over F p , thus highlighting the importance of the linearity assumption for our result. 相似文献
949.
950.
Bhattacharyya Suvanjan Vishwakarma Devendra Kumar Goel Varun Chamoli Sunil Issakhov Alibek Meyer Josua P. 《Journal of Thermal Analysis and Calorimetry》2021,145(3):1445-1465
Journal of Thermal Analysis and Calorimetry - Baffles are used for heat transfer enhancement in heat exchanger tubes. However, they also increase the friction factor in the flow channel.... 相似文献