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261.
Cyclobutylchlorocarbene can be intercepted by simple alkenes in successful competition with intramolecular ring expansion and hydride migration reactions. 相似文献
262.
[reaction: see text] Stereoselective isomerization of C-allyl glycosides into (E)-C-vinyl glycosides or (Z)-exo-glycals was carried out in the presence of the cationic iridium(I) catalyst [(Ph(2)MeP)(2)Ir(cod)PF(6)]. The products of the isomerization were affected by the relative 1,2-stereochemical relationships and by the nature of the protecting groups. These effects are discussed along with a plausible reaction mechanism. 相似文献
263.
In this article we give a characterization of the convergence of projection methods which are useful for approximating the
Moore-Penrose inverse of a closed densely defined operator between Hilbert spaces. We illustrate the main theorem with an
example. Also a procedure for constructing the admissible sequence of projections is discussed. 相似文献
264.
Ramesh Kapadia† ‡ 《International Journal of Mathematical Education in Science & Technology》2013,44(4):431-433
We develop one criterion for the selection of the content of a mathematics syllabus. We advocate the importance of the biogenetic law and stress the importance of a historical perspective in mathematical education. 相似文献
265.
Muthu Thangaraj Bibhuti Ranjan Ramesh Muthusamy Arul Murugesan Robert Moonsamy Gengan 《Journal of heterocyclic chemistry》2019,56(3):867-885
A series of fused quinolinyl and quinolonyl pyrans were synthesized via a one‐pot reaction of quinolinyl and quinolonyl carbaldehydes, malononitrile, and a 1,3‐diketone. The reactions were catalyzed by a new humic acid supported 1‐butyl‐3‐methyl imidazolium thiocyanate ionic liquid under microwave irradiation conditions. Antimicrobial, antioxidant, and toxicity studies displayed various biological activities depending on structure of the pyrans. 相似文献
266.
Ramesh Kumar C. Vijayakumar V. Suresh A. Jayalakshmi S. Sivaraman N. 《Journal of Radioanalytical and Nuclear Chemistry》2019,321(2):617-627
Journal of Radioanalytical and Nuclear Chemistry - Radiolytic stability of polymeric resins is an important aspects in nuclear materials processing. The different dosage of gamma radiation was... 相似文献
267.
We present a stability map which predicts the domains of shear instability due to grain rotation in nanocrystalline materials. The onset of this mode of instability is influenced by grain-size-dependent mechanisms and the length-scale of intergranular interaction. The map shows the grain size regimes that are inherently susceptible to this mode for a range of materials. In the amorphous limit, the model predicts embryonic nuclei sizes of about 10-50 nm, which agrees well with the shear band thicknesses for many metallic glasses. 相似文献
268.
M. Narasimhulu S. Malla Reddy K. Rajesh N. Suryakiran D. Ramesh Y. Venkateswarlu 《Heteroatom Chemistry》2008,19(4):429-433
A mild and highly efficient synthesis of chiral tetrahydroquinolino pyranose derivatives is described. The reaction of a chiral α,β‐unsaturated aldehyde containing a hydroxyl group with different aryl amines using lanthanum(III) nitrate hexahydrate as a catalyst afforded corresponding chiral tetrahydroquinolinated pyranosides in excellent yields. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:429–433, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20441 相似文献
269.
Kiran Ramesh Kenneth Granlund Michael V. Ol Ashok Gopalarathnam Jack R. Edwards 《Theoretical and Computational Fluid Dynamics》2018,32(2):109-136
A leading-edge suction parameter (LESP) that is derived from potential flow theory as a measure of suction at the airfoil leading edge is used to study initiation of leading-edge vortex (LEV) formation in this article. The LESP hypothesis is presented, which states that LEV formation in unsteady flows for specified airfoil shape and Reynolds number occurs at a critical constant value of LESP, regardless of motion kinematics. This hypothesis is tested and validated against a large set of data from CFD and experimental studies of flows with LEV formation. The hypothesis is seen to hold except in cases with slow-rate kinematics which evince significant trailing-edge separation (which refers here to separation leading to reversed flow on the aft portion of the upper surface), thereby establishing the envelope of validity. The implication is that the critical LESP value for an airfoil–Reynolds number combination may be calibrated using CFD or experiment for just one motion and then employed to predict LEV initiation for any other (fast-rate) motion. It is also shown that the LESP concept may be used in an inverse mode to generate motion kinematics that would either prevent LEV formation or trigger the same as per aerodynamic requirements. 相似文献
270.
Umesh Todmal Suresh P. Sulochana Mohd Zainuddin Ravi Kanth Bhamidipati Swapan Kumar Samanta Gurulingappa Hallur Sridharan Rajagopal Sriram Rajagopal Ramesh Mullangi 《Chromatographia》2018,81(3):457-468
A sensitive and rapid LC–MS/MS method was developed and validated for the simultaneous quantitation of five selective KCNQ channel openers, namely ICA-27243, ML-213, PF-05020182, SF-0034 and flupirtine in mice plasma as per regulatory guideline. The analytes and the internal standard (IS; flupirtine-d 4 ) were extracted from 50 µL mice plasma by liquid–liquid extraction, followed by chromatographic separation using an Atlantis C18 column with an isocratic mobile phase comprising 0.2% formic acid: acetonitrile (20:80, v/v) at a flow rate of 0.6 mL min?1 within 2.5 min. Detection and quantitation was done by multiple reaction monitoring on a triple quadrupole mass spectrometer following the transitions: m/z 268.9 → 140.8, 258.1 → 95.1, 367.2 → 269.1, 322.2 → 248.2, 305.7 → 196.4 and 309.1 → 196.1 for ICA-27243, ML-213, PF-05020182, SF-0034, flupirtine and the IS, respectively, in the positive ionization mode. The calibration curves were linear from 1.00 to 2008 ng mL?1 for all the analytes with r2 ≥ 0.99. The intra- and inter-batch accuracy and precision (% CV) across quality controls varied from 90.0 to 113 and 2.64 to 13.0; 93.8 to 114 and 3.15 to 14.9%, respectively, for all the analytes. Analytes were found to be stable under different stability conditions. The method was applied to a pharmacokinetic study in mice. 相似文献