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991.
992.
P Singh 《Journal of Chemical Sciences》1986,97(1):91-95
The estrogen receptor binding affinity of 2-phenylindoles is found to be significantly correlated with Kier’s first-order
valence molecular connectivity index. The correlation equations obtained provide a much simple rationale to design more potent
compounds and help in predicting the potency of new compounds. 相似文献
993.
A general solution of Einstein field equations corresponding to a charged fluid distribution on the background of higher dimensional
spheroidal space-time is obtained. The solution generates several known solutions for superdense star having spheroidal space-time
geometry.
Formerly V. Regional College of Engineering 相似文献
994.
Flow past a circular cylinder for Re=100 to 107 is studied numerically by solving the unsteady incompressible two‐dimensional Navier–Stokes equations via a stabilized finite element formulation. It is well known that beyond Re ~ 200 the flow develops significant three‐dimensional features. Therefore, two‐dimensional computations are expected to fall well short of predicting the flow accurately at high Re. It is fairly well accepted that the shear layer instability is primarily a two‐dimensional phenomenon. The frequency of the shear layer vortices, from the present computations, agree quite well with the Re0.67 variation observed by other researchers from experimental measurements. The main objective of this paper is to investigate a possible relationship between the drag crisis (sudden loss of drag at Re ~ 2 × 105) and the instability of the separated shear layer. As Re is increased the transition point of shear layer, beyond which it is unstable, moves upstream. At the critical Reynolds number the transition point is located very close to the point of flow separation. As a result, the shear layer eddies cause mixing of the flow in the boundary layer. This energizes the boundary layer and leads to its reattachment. The delay in flow separation is associated with narrowing of wake, increase in Reynolds shear stress near the shoulder of the cylinder and a significant reduction in the drag and base suction coefficients. The spatial and temporal power spectra for the kinetic energy of the Re=106 flow are computed. As in two‐dimensional isotropic turbulence, E(k) varies as k?5/3 for wavenumbers higher than energy injection scale and as k?3 for lower wavenumbers. The present computations suggest that the shear layer vortices play a major role in the transition of boundary layer from laminar to turbulent state. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
995.
Brajendra K. Singh Christian V. Stevens Davy R.J. Acke Erik V. Van der Eycken 《Tetrahedron letters》2009,50(1):15-4274
A continuous flow procedure has been elaborated for the copper(II)-mediated N- and O-arylation of a range of compounds with arylboronic acids using a commercial microreactor setup. The compounds could be continuously generated in good yields paving the way for efficient scalability. 相似文献
996.
997.
998.
Mona Khare Akhilesh Kumar Singh 《Journal of Mathematical Analysis and Applications》2008,344(1):238-252
The aim of this paper is to introduce and investigate the concept of pseudo-atoms of a real-valued function m defined on an effect algebra L; a few examples of pseudo-atoms and atoms are given in the context of null-additive, null-null-additive and pseudo-null-additive functions and also, some fundamental results for pseudo-atoms under the assumption of null-null-additivity are established. The notions of total variation |m|, positive variation m+ and negative variation m− of a real-valued function m on L are studied elaborately and it is proved for a modular measure m (which is of bounded total variation) defined on a D-lattice L that, m is pseudo-atomic (or atomic) if and only if its total variation |m| is pseudo-atomic (or atomic). Finally, a Jordan type decomposition theorem for an extended real-valued function m of bounded total variation defined on an effect algebra L is proved and some properties on decomposed parts of m such as continuity from below, pseudo-atomicity (or atomicity) and being measure, are discussed. A characterization for the function m to be of bounded total variation is established here and used in proving above-mentioned Jordan type decomposition theorem. 相似文献
999.
Alan R. Katritzky Nabin K. Meher Sureyya Hanci Reena Gyanda Srinivasa R. Tala Sindhu Mathai Randolph S. Duran Sophie Bernard Firouzeh Sabri Sandeep K. Singh Jacek Doskocz David A. Ciaramitaro 《Journal of polymer science. Part A, Polymer chemistry》2008,46(1):238-256
Fourteen commercial polyols have been characterized by GPC, NMR spectroscopy, and elemental analysis. From these, eight corresponding tosylates, six nitrate esters, seven mesylates, 13 alkynes, and 14 azides have been prepared and all these derivatives have been fully characterized. Five alkyne monomers and eight azide monomers were also prepared. Twelve alkynes and 13 azides (functionality 2–4) were combined in 1,3‐dipolar cycloaddition reactions under neat conditions to prepare triazole‐cured polymers, avoiding any heavy metal catalyst. Characterization by NMR spectroscopy, elemental analysis, and gel permeation chromatography indicated triazole polymers 14 , 22 , 23 , 28 , and 30 with degrees of polymerization of 17–28 to be the best candidates for future work. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 238–256, 2008 相似文献
1000.