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81.
Kalyan Kali Sengupta Biswanath Basu Shipra Sengupta Sanghamitra Nandi 《Polyhedron》1983,2(10):983-986
Hypophosphite ion is oxidised by Au(III) in aqueous hydrochloric acid to give phosphorus acid and Au(I). The kinetics of the reaction has been studied spectrophotometrically in the UV region at different temperatures. The oxidation of hypophosphorous acid is first order with respect to both Au(III) and substrate. Hydrogen ion has no effect on the rate in acid media (0.15–1.0)M. The energy and entropy of activations are 128 ± 3.0kJ mol?1 and 135.8 ± 6.5 JK?1 mol?1 respectively. The results are interpreted in terms of the probable formation of intermediate Au(lI). 相似文献
82.
The development of the theory of electron capture processes in ion-atom collisions is reviewed in the present work. The formal theory of scattering is used to obtain the Born and the distorted wave Born series for the rearrangement scattering matrix. On the basis of these series, the applications of the first and second Born approximation, the OBK approximation, the DWBA and the Padé approximants to electron capture processes are discussed. The impulse approximation, the Faddeev method and the second order potential method are also explained. The results of the investigations of the high energy behaviour of the charge transfer cross section based on the Faddeev-Watson multiple scattering expansion are analysed.The methods of molecular and atomic eigenfunction expansions are presented and their relative merits discussed. The semi-classical treatment for determining the differential electron capture probability is reviewed. Results obtained in works utilising expansions in Sturmian, Gaussian and pseudo-state wave functions are also presented. An integral equation approach to the close coupling approximation is described. The field theoretic approach to investigate the electron capture process is discussed in the last section.The results obtained by different theoretical methods are compared with available experimental results. 相似文献
83.
A simple method for the amperometric estimation of N-cyclohexyl-2-benzothiazole sulphenamide, N-dicyclohexyl-2-benzothiazole sulphenamide, 2-(morpholinothio)benzothiazole and N-tert.-butyl-2-benzothiazole sulphenamide is reported. The results are obtained within 5 min and are correct within +/- 2.0%. 相似文献
84.
X-ray photoemission spectra of vacuum cleaved LiC6, prepared from highly oriented pyrolytic graphite, provide a direct measure of the filling of the graphite π bands by electrons from Li. The resulting Fermi energy shift is in agreement with recent band structure calculations and indicates near unity charge transfer from Li. Core level spectra exhibit shifts compatible with the expected charge transger and line shapes showing strong asymmetries resulting from the metallic character of this compound. 相似文献
85.
B. K. Basu 《Czechoslovak Journal of Physics》1978,28(4):374-384
A set of recurrence relations connecting the matrix elements of finite transformation belonging to the same irreducible representation of SU(4) is used to obtain a wide class of matrix elements. An expression for the Clebsch-Gordan coefficient is obtained by integrating the product of three matrix elements belonging to three different irreducible representations of the group. The symmetry properties of the matrix elements and the Clebsch-Gordan coefficients are discussed.The author is grateful to Professors S.Datta Majumdar and G.Bandyopadhyay of the Department of Physics, I.I.T., Kharagpur, for many helpful discussions. This work was supported by the C.S.I.R., Government of India. 相似文献
86.
Sengupta T Dutta Choudhury S Basu S 《Journal of the American Chemical Society》2004,126(34):10589-10593
The interaction between 2'-deoxyadenosine and the model antitumor drug menadione has been studied in organic solvent and in micellar medium. The aim of the work is to elucidate the mechanism of this drug-nucleoside interaction and to determine the environmental effects. Laser flash photolysis and magnetic field effect are used to detect the transients and their spin states. The results indicate that H atom transfer and electron transfer are the operative mechanisms depending upon the medium. 相似文献
87.
A simple and efficient method has been developed for chemoselective deprotection of phenolic methoxymethyl (MOM) ethers using silica-supported sodium hydrogen sulfate as a heterogeneous catalyst. The conversions occur at room temperature, and the yields of the deprotected phenols are excellent. The method is suitable for deprotection of phenolic MOM ethers of multifunctional bioactive natural products. 相似文献
88.
89.
Vishal Kesari P. K. Jain B. N. Basu 《International Journal of Infrared and Millimeter Waves》2007,28(6):443-449
In the method of tapering the cross section of the interaction structure for broadbanding a gyro-TWT, the different portions
of the interaction length of the tapered-cross-section waveguide become effective for different frequency ranges if the magnetic
field and beam parameters are profiled to maintain the condition of electron cyclotron resonance throughout the interaction
length. In the present paper, the study of profiling the magnetic field and beam parameters in steps of the stepped analytical
model of a double-tapered disc-loaded circular waveguide was made throughout the steps of the model. In the observed profile,
the magnetic flux density in a typical step relative to its value in first-step decreases from first-step (gun-end) to end-step
(collector-end) of the model considering the up-tapering schemes, in which structure parameters increase from gun-end to collector-end.
Also, the transverse beam velocity in a typical step relative to its value in first-step decreases from gun-end to collector-end.
However, the Larmor radius in a typical step relative to its value in first-step as well as the hollow-beam radius in a typical
step relative to its value in first-step, both increase from gun-end to collector-end in the model considering the up-tapering
schemes. 相似文献
90.
Tushar S. Basu Baul Keisham Surjit Singh Michal Hol?apek 《Journal of organometallic chemistry》2005,690(6):1581-1587
The complex, [(PhCH2)2{O2CC6H4{N(H)N(C6H3-4(O)-5-O)}-o}Sn]2 (1), is obtained as the exclusive reaction product from the reaction of sodium 2-[(E)-2-(3-formyl-4-hydroxyphenyl)-1-diazenyl]benzoate and (PhCH2)3SnCl. The reaction possibly proceeds via Dakin type rearrangements where arylazosalicylaldehyde is oxidized to arylazocatechol, followed by facile Sn-C bond cleavage. Complete assignments were achieved by 1H, 13C, 2D 1H-119Sn HMQC (119Sn chemical shift), 1D gs 1H-15N HMQC (1J(15N, 1H) coupling constant) NMR and ESI-MS. The crystal structure of compound 1 as determined by X-ray diffraction analyses shows a cyclic centrosymmetric dinuclear moiety linked into extended chains by pairs of long Sn?O contacts of approximately 3.2 Å. Two polymorphs were identified and their structures differ primarily in the packing arrangement afforded by the benzyl groups. In one polymorph, when viewed along the Sn?Sn vector, the benzyl groups at each Sn-atom are oriented to form an S-shape, while they form a U-shape in the second polymorph. 相似文献