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61.
V.M. MathewC.S. Menon K.P. Jayachandran 《Journal of Physics and Chemistry of Solids》2002,63(10):1835-1838
The second- and third-order elastic constants and pressure derivatives of second-order elastic constants of tetragonal β-tin have been obtained using the deformation theory. The strain energy density derived using the deformation theory is compared with the strain dependent lattice energy obtained from the elastic continuum model approximation to get the expressions for the second- and third-order elastic constants. Higher order elastic constants are a measure of the anharmonicity of a crystal lattice. The 12 non-vanishing third-order elastic constants and the six pressure derivatives of the second-order elastic constants in tetragonal β-tin are obtained in the present work and are compared with the available experimental values. The second-order elastic constant C33 obtained in the present study is in reasonable agreement with the experimental values. The third-order elastic constants are generally one order of magnitude greater than the second-order elastic constants as expected of a crystalline solid. The third-order elastic constant C333 is higher in magnitude than all other values. This shows a greater anharmonicity of β-tin along the c-axis direction of the crystal. 相似文献
62.
Vijay Nair P.B. Beneesh V. Sreekumar S. Bindu Rajeev S. Menon Ani Deepthi 《Tetrahedron letters》2005,46(2):201-203
The zwitterionic species generated by the addition of dimethoxycarbene to dimethyl butynedioate is trapped by arylidenemalononitrile to yield cyclopentenone derivatives. 相似文献
63.
A. Reginiv R. Kaur N. Sudha S. C. Menon H. B. Singh 《Journal of Chemical Sciences》1995,107(4):431-442
A range of novel bi-, tri- and multidentate organotellurium ligands containing Te and N donor atoms and their derivatives
have been synthesised. The synthetic strategy involves telluration of orthochelating, monoanionic substrates derived from
the following arylamines: N,N-dimethylbenzylamine, (S)-(-)-N,Ndimethyl-1-phenethylamine, N,N-dimethylnaphthylamine, (N,N-di-methylaminomethy
l) ferrocene, tricarbony1(N, N-dimethylbenzenemethanamine) chromium and 2-(3-thienyl)-pyridine. In addition novel chiral hybrid
Schiff base ligands have been prepared by the condensation reaction of bis(o-formylphenyl) telluride ando-butyltellurobenzaldehyde with (R)-(+)-l-phenethylamine and (1R, 2S)-(-)-norephedrine. 相似文献
64.
Examples of progress in fabricating branched multi-terminal multi-wall and single-wall carbon nanotube junctions as predicted by nanotechnology simulations, using template growth and nanowelding techniques, respectively, have been briefly reviewed in this report. It is argued that similar general progress in computational nanotechnology-driven fabrication of applications in other nanomaterials such as nanotubes, fullerenes, nanowires, quantum dots, DNA molecules, and nanoparticle-based systems and devices are also feasible. This is because, at nanometer length scale, system sizes have shrunk sufficiently small such that it is feasible to simulate the structural, stability, and physical and chemical characteristics with very high accuracy predictive simulations. 相似文献
65.
K.V Menon 《Discrete Mathematics》1984,48(1):87-93
Let Δ(α + β) = |Hλ2?r+1| where Hr is the complete symmetric function in (α1 + β1), (α2 + β2), …, (αn + βn). It is proved that Δ(α + β) ? Δ(α) + Δ(β). This inequality is generalised for certain symmetric functions defined by Littlewood. Let . Then we prove that Ω(α + β) ? Ω(α) + Ω(β). Here λ1, λ2, λ3, …, λn is a partition such that λn > λn?1 > ··· > λ2 > λ1. 相似文献
66.
The application of Delahay’s theory of kinetic polarographic currents as applied to the reduction of pyruvic acid has been examined. It is shown that the agreement between Delahay’s theory and the available data is more satisfactory, if one assumes that the current is controlled by the rate of the reaction between pyruvate ion and water molecule forming pyruvic acid and hydroxyl ion, than when one assumes the mechanism suggested by the earlier workers involving the rate of reaction between pyruvate ion and hydrogen-ion, both from the point of view of the magnitude of the diffusion current as well as its pH dependence. The results give an indication of the latter reaction being sluggish due to the activation energy requirements. 相似文献
67.
Pure Potassium chloride, when quenched rapidly from melt shows pronounced glow peak at 250°K. The intensity of the glow peak has been found to decrease by heating the specimen to around 450°K, or by subjecting it to pressure. A qualitative interpretation of these effects has been offered on the basis of quenched —in cation —anion vacancy pairs. 相似文献
68.
69.
The generalised Gruneisen parameters γ′ = ?? log ω/??′ and γ″ = ?? log ω/??″ have been calculated for various normal mode frequencies using the force model for Zirconium obtained on Keating's approach. There is a general agreement between the normalised frequency distribution curve of Zirconium obtained on the present model and that of Bezdek et al. The temperature dependence of the effective Gruneisen functions and has been calculated using the procedure of Blackman. The high temperature limits of , and are in good agreement with those obtained by Goldak et al. from an analysis of the thermal expansion data of Zirconium. 相似文献
70.
The transbilayer flip-flop of early intermediates in the glycosylphosphatidylinositol (GPI) biosynthetic pathway has been demonstrated using novel fluorescent GPI probes and a biochemical reconstitution approach. 相似文献