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51.
Neeraj Shukla Saurabh K. BoseMihir Sarkar Nobin BanerjiAnjan K. Gupta Harish C. Verma 《Journal of magnetism and magnetic materials》2012
2 MeV protons and 1 MeV carbon ions are bombarded on highly oriented pyrolytic graphite (HOPG) samples and their electronic transport measurements are carried out in the presence of magnetic field. The Magneto-Resistance (MR) measurements show measurable hysteresis in the resistance value after ion beam irradiation for the in-plane magnetic field direction as well as for the out-of-plane field direction. The MR depends on the thickness of the flake and the method of its separation from the bulk HOPG. The results substantiate that the ferromagnetic coupling between the magnetic moments at the vacancy defect sites in HOPG sensitively depends on the average defect separation. The average defect separation range of 1.7–0.5 nm allows only a part of the 40 μm thick proton beam irradiated sample to go for ferromagnetic ordering. Similar conclusions are drawn from carbon ion irradiated HOPG flake. The irradiation increases the resistance of the flake as well. 相似文献
52.
Prashant T. Mistry Nimesh R. Kamdar Dhaval D. Haveliwala Saurabh K. Patel 《Journal of heterocyclic chemistry》2012,49(2):349-357
A variety of pyrano[2,3‐d]pyrimidine‐5‐one derivatives 5 , 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 6 , 6a , 6b , 6c , 6d , 6e , 6f , 6g , 6h , 6i , 6j have been synthesized from 6‐amino‐4‐(substituted phenyl)‐5‐cyano‐3‐methyl‐1‐phenyl‐1,4‐dihydropyrano[2,3‐c]pyrazole derivatives 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j via cyclization using formic acid and acetic acid. All the newly synthesized compounds have been characterized by IR, 1H NMR, 13C NMR, and elemental analysis. All the synthesized compounds have been screened for antibacterial, antifungal and antitubercular activity. J. Heterocyclic Chem., (2012). 相似文献
53.
The Ramanujan Journal - In Maier and Tenenbaum (Invent Math 76(1):121–128, 1984), Tenenbaum and the first author proved an old conjecture of Paul Erd?s about the propinquity of divisors... 相似文献
54.
Joshua W. M. MacMillan Katherine M. Marczenko Prof. Dr. Erin R. Johnson Prof. Dr. Saurabh S. Chitnis 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(71):17134-17142
The addition of Sb−H bonds to alkynes was reported recently as a new hydroelementation reaction that exclusively yields anti-Markovnikov Z-olefins from terminal acetylenes. We examine four possible mechanisms that are consistent with the observed stereochemical and regiochemical outcomes. A comprehensive analysis of solvent, substituent, isotope, additive, and temperature effects on hydrostibination reaction rates definitively refutes three ionic mechanisms involving closed-shell charged intermediates. Instead the data support a fourth pathway featuring open-shell neutral intermediates. Density-functional theory (DFT) calculations are consistent with this model, predicting an activation barrier that is in agreement with the experimental value (Eyring analysis) and a rate limiting step that is congruent with the experimental kinetic isotope effect. We therefore conclude that hydrostibination of arylacetylenes is initiated by the generation of stibinyl radicals, which then participate in a cycle featuring SbII and SbIII intermediates to yield the observed Z-olefins as products. This mechanistic understanding will enable rational evolution of hydrostibination as a synthetic methodology. 相似文献
55.
A gauge-invariant Rarita-Schwinger theory of a massive spin-3/2 particle interacting with external electromagnetic, gravitational and dilaton fields is obtained by Kaluza-Klein reduction of a massless Rarita-Schwinger theory with graviational interaction. Fermionic gauge invariance serves to determine the background equations of motion. The couplings with external fields obtained by the Kaluza-Klein reduction are shown to lead to the absence of the classical Velo-Zwanziger problem and on quantizing using Dirac's procedure, the field anticommutators are found to be positive definite. 相似文献
56.
Saurabh D Rindani 《Pramana》1995,45(1):263-276
The prospects of experimental detection ofCP violation ate + e ? and\(pp/p\bar p\) colliders are reviewed. After a general discussion on the quantities which can measureCP violation and on the implications of theCPT theorem, various possibilities of measuringCP violation arising outside the standard model are taken up.CP violation in leptonic processes, especially polarization effects ine + e ?→l + l ? are discussed next.CP violation in\(t\overline t \) andW + W ? production and decay is also described. 相似文献
57.
Otto P. Strausz Ratnakar K. Gosavi George R. Demaré Imre G. Csizmadia 《Chemical physics letters》1979,62(2):339-340
The rotational barrier height Erot in the lowest triplet state oxirane molecule was calculated to be 26.3 kcal/mole using a double zeta basis set with partial geometry optimization. This suggest ldrelaxedrd rotation and the computed e(T1- E(So) + Erot value is commensurate with the enthalpy change for the oxirane-forming O(3P) + C2H4 reaction, thus providing a rationale for the stereochemical features of the reaction. 相似文献
58.
Beena Annie Kuruvilla Madhukar Zambre Suresh Gosavi Sucheta Gorwadkar A. Datta S. A. Gangal S. K. Kulkarni 《Journal of polymer science. Part A, Polymer chemistry》1994,32(12):2275-2281
Plasma polymerized methyl methacrylate (PPMMA) films have been synthesised on silicon substrates in RF glow discharge using oxygen plasma. The electron beam delineation sensitivity of the PPMMA films has been studied systematically by varying oxygen and monomer flow rates. X-ray photoelectron spectroscopy (XPS) analysis clearly illustrates how C/O ratio in the films determines the properties of PPMMA films as electron beam resist. © 1994 John Wiley & Sons, Inc. 相似文献
59.
60.
Gosavi Seema A. Shirkhedkar Atul A. Jaiswal Yogini S. Surana Sanjay J. 《平面色谱法杂志一现代薄层色谱法》2006,19(3):228-232
JPC – Journal of Planar Chromatography – Modern TLC - A simple, rapid, and reliable HPTLC method has been established for determination of pantoprazole sodium sesquihydrate in tablets.... 相似文献