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1.
Lokenath Debnath 《Journal of Mathematical Analysis and Applications》2007,333(1):164-190
This paper deals with recent developments of linear and nonlinear Rossby waves in an ocean. Included are also linear Poincaré, Rossby, and Kelvin waves in an ocean. The dispersion diagrams for Poincaré, Kelvin and Rossby waves are presented. Special attention is given to the nonlinear Rossby waves on a β-plane ocean. Based on the perturbation analysis, it is shown that the nonlinear evolution equation for the wave amplitude satisfies a modified nonlinear Schrödinger equation. The solution of this equation represents solitary waves in a dispersive medium. In other words, the envelope of the amplitude of the waves has a soliton structure and these envelope solitons propagate with the group velocity of the Rossby waves. Finally, a nonlinear analytical model is presented for long Rossby waves in a meridional channel with weak shear. A new nonlinear wave equation for the amplitude of large Rossby waves is derived in a region where fluid flows over the recirculation core. It is shown that the governing amplitude equations for the inner and outer zones are both KdV type, where weak nonlinearity is balanced by weak dispersion. In the inner zone, the nonlinear amplitude equation has a new term proportional to the 3/2 power of the difference between the wave amplitude and the critical amplitude, and this term occurs to account for a nonlinearity due to the flow over the vortex core. The solution of the amplitude equations with the linear shear flow represents the solitary waves. The present study deals with the lowest mode (n=1) analysis. An extension of the higher modes (n?2) of this work will be made in a subsequent paper. 相似文献
2.
Sufficient conditions for asymptotic behavior of the solutions of nonlinear forced neutral delay differential equations with impulses are found. The results given in [2,4,6,7] are generalized and improved. 相似文献
3.
4.
Indole-2-yl-prop-2-ynyl sulfides, under thiophenol-mediated alkenyl radical cyclization conditions, afforded exclusively 4-thiophenyl-2,3,4,9-tetrahydrothiopyrano[2,3-b]indoles or 3-thiophenylmethyl-2,3,8-trihydrothieno[2,3-b]indoles depending on the substituent at the indole nitrogen. 相似文献
5.
A vesicle-forming chiral cationic surfactant (1R,2S)-(-)-N-dodecyl-N-methyl-ephedrinium bromide was evaluated as a pseudo-stationary phase in micellar electrokinetic chromatography (MEKC) for enantioseparation of eight non-steroidal anti-inflammatory drugs e.g., carprofen, flurbiprofen, fenoprofen, ibuprofen, indoprofen, ketoprofen, naproxen and suprofen by capillary electrophoresis. The effects of varying experimental conditions such as pH and concentration of surfactant in the running buffer on the enantiomer separation of the drugs are reported. A mixture of five of the above drugs was separated and each enantiomeric pair was also separated simultaneously in a single run by use of the surfactant. The strong electrostatic interactions between the analytes and the vesicles seemed to have a major role in the enantiomeric separation of the profens. 相似文献
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7.
Piyali Bagchi Khatua Ujjal Debnath 《International Journal of Theoretical Physics》2012,51(12):3701-3720
In this work, we have considered Cardassian Universe in Ho?ava-Lifshitz gravity. Four types of Cardassian Universe models i.e., polytropic/power law, modified polytropic, exponential and modified exponential models have been considered for accelerating models. The natures of statefinder parameters, deceleration parameter, Om diagnostic and EoS parameters have been investigated for all types of Cardassian models in Ho?ava-Lifshitz gravity. 相似文献
8.
Using classical analytic techniques, the Wilker–Anglesio inequality and parameterized Wilker inequality for hyperbolic functions are proved. The main result is then applied to deriving a hyperbolic analogue of the Sándor–Bencze inequality. 相似文献
9.
Dr. Renata Kaczmarek Samuel Ward Dipra Debnath Taisiya Jacobs Alexander D. Stark Dariusz Korczyński Prof. Dr. Anil Kumar Prof. Dr. Michael D. Sevilla Dr. Sergey A. Denisov Dr. Viacheslav Shcherbakov Dr. Pascal Pernot Prof. Dr. Mehran Mostafavi Prof. Dr. Roman Dembinski Prof. Dr. Amitava Adhikary 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(43):9495-9505
The directionality of the hole-transfer processes between DNA backbone and base was investigated by using phosphorodithioate [P(S−)=S] components. ESR spectroscopy in homogeneous frozen aqueous solutions and pulse radiolysis in aqueous solution at ambient temperature confirmed initial formation of G.+-P(S−)=S. The ionization potential of G-P(S−)=S was calculated to be slightly lower than that of guanine in 5′-dGMP. Subsequent thermally activated hole transfer from G.+ to P(S−)=S led to dithiyl radical (P-2S.) formation on the μs timescale. In parallel, ESR spectroscopy, pulse radiolysis, and density functional theory (DFT) calculations confirmed P-2S. formation in an abasic phosphorodithioate model compound. ESR investigations at low temperatures and higher G-P(S−)=S concentrations showed a bimolecular conversion of P-2S. to the σ2-σ*1-bonded dimer anion radical [-P-2S 2S-P-]− [ΔG (150 K, DFT)=−7.2 kcal mol−1]. However, [-P-2S 2S-P-]− formation was not observed by pulse radiolysis [ΔG° (298 K, DFT)=−1.4 kcal mol−1]. Neither P-2S. nor [-P-2S 2S-P-]− oxidized guanine base; only base-to-backbone hole transfer occurs in phosphorodithioate. 相似文献
10.
Structural Chemistry - The role of Ti(II) sandwich complex, [Cp2Ti], generated by the combination of [Cp2TiCl2] and two equivalents of nBuLi, in situ, in toluene has been investigated theoretically... 相似文献