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91.
Sabyasachi Ghosh S. Mallik Sourav Sarkar 《The European Physical Journal C - Particles and Fields》2010,70(1-2):251-262
We analyse the structure of one-loop self-energy graphs for the ρ meson in real time formulation of finite temperature field theory. We find the discontinuities of these graphs across the unitary and the Landau cuts. These contributions are identified with different sources of medium modification discussed in the literature. We also calculate numerically the imaginary and the real parts of the self-energies and construct the spectral function of the ρ meson, which are compared with an earlier determination. A significant contribution arises from the unitary cut of the π ω loop, that was ignored so far in the literature. 相似文献
92.
Danne Ashruba B. Choudhari Amit S. Sarkar Dhiman Sangshetti Jaiprakash N. Khedkar Vijay M. Shingate Bapurao B. 《Research on Chemical Intermediates》2018,44(10):6283-6310
Research on Chemical Intermediates - The synthesis of a new series of triazole-biscoumarin conjugates by using a molecular hybridization approach is described. The newly synthesized compounds... 相似文献
93.
M. Chawda N. Patel K. C. Sebastian D. R. S. Somayajulu M. Sarkar R. P. Singh 《辐射效应与固体损伤》2013,168(6):361-364
Radiation-induced defects are studied in cubic rhodium metal, using the local probe technique ‘Time differential perturbed angular correlation’ (TDPAC) at liquid N2 temperature. Isochronal annealing was done at 300, 1073 and 1473 K temperatures. The irradiated sample showed two quadrupole interaction frequencies at 1150 and 93 MHz. The low frequency disappeared at room-temperature annealing, which was assigned to In trapped at a vacancy, whereas the higher frequency remained up to high temperatures and was attributed to In trapped at Rh–C complexes in the Rh matrix. 相似文献
94.
Sarben Sarkar 《Foundations of Physics》2010,40(7):978-1003
The role of CPT invariance and consequences for bipartite entanglement of neutral (K) mesons are discussed. A relaxation of CPT leads to a modification of the entanglement which is known as the ω effect. The relaxation of assumptions required to prove the CPT theorem are examined within the context of models of space-time foam. It is shown that the evasion of the EPR type entanglement
implied by CPT (which is connected with spin statistics) is rather elusive. Relaxation of locality (through non-commutative geometry) or
the introduction of an environment do not by themselves lead to a destruction of the entanglement. One model of the environment,
which is based on non-critical strings and D-particle capture and recoil, leads to a specific momentum dependent stochastic
contribution to the space-time metric and consequent change in the neutral meson bipartite entanglement. Although the class
of models producing the omega effect is non-empty, the lack of an omega effect is demonstrated for a wide class of models
based on thermal like baths which are often considered as generic models appropriate for the study of space-time foam. 相似文献
95.
The doped fiber amplifier has already emerged as the indispensable potential candidate for repeaterless transmission of information processed through single mode. Therefore the fundamental modal field in the doped single-mode fiber needs to be accurately prescribed both in the pump as well as the signal to facilitate further study of their variation with distance. Based on the novel approximation of the fundamental modal field in graded-index fiber, we formulate analytical expression as regards the variation of modal intensity with radial distance from the axis of the fiber both for the pump and the signal fields and estimate such variation for step-index fiber of some typical V values as example. We find that our estimation matches excellently with the available exact results in case of both the pump and the signal and is shown to be much superior to one-parameter Gaussian approximation. In addition, our methodology involves less computation compared to the exact analysis involving cumbersome computation. 相似文献
96.
The process of infrared multiple photon dissociation (IRMPD) of molecules is of great fundamental importance and has practical
significance, such as isotope separation etc. Unfortunately, a clear insight into the process has been hindered by the bewildering
array of important variables affecting MPD. The dissociation probability γ (φ) i.e. the yield has been found to be a sensitive
function of laser fluence φ along with numerous other parameters like laser frequency, gas pressure etc. We have shown that
in single frequency IRMPD, an accurate quantitative characterization of the dissociation probability can be adequately expressed
by a ‘power law’ model with two fitting parameters namely critical fluence, φc and multiphoton order,m. This model was exploited in analysing our MPD results on various systems. However, the small isotope shift encountered in
heavy elements and the sticking phenomenon observed in small light molecules restrict respectively the separation factor and
the dissociation yield. These problems can effectively be tackled by irradiation with multifrequency laser beams which can
be chosen appropriately on the basis of spectroscopic features. Based on our success in single frequency model, multifrequency
IRMPD is modelled by a functional form containing the product of power law terms for individual fluences on irradiation frequencies.
This model is successfully benchmarked with our experimental results on multifrequency LIS of tritium. Such knowledge can
be utilized for appropriate separation process design, evaluation and optimization. 相似文献
97.
P. B. Sarkar N. R. Dhar J. M. Kalthoff J. Holluta J. Obrist G. Krüss J. Nicklès A. Skrabal J. Preiss O. T. Christensen M. Geloso P. Dubois F. P. Treadwell R. W. Coltman A. Gorgeu O. Hauser F. Wirth und O. Hackl 《Fresenius' Journal of Analytical Chemistry》1930,80(5-6):216-228
Ohne Zusammenfassung 相似文献
98.
99.
A. Chatterjee A. Sarkar Sourav Bhattacharya P. Mukherjee N. Gayathri P. Barat 《Physics letters. A》2008,372(22):4016-4020
Tensile tests were carried out by deforming polycrystalline samples of substitutional Al–2.5%Mg alloy at room temperature for a range of strain rates. The Portevin–Le Chatelier (PLC) effect was observed throughout the strain rate regime. The deformation bands in this region are found to be of type A in nature. From the analysis of the experimental stress time series data we could infer that the dynamics of type A dislocation band propagation is a Markov process. 相似文献
100.
Daniel C. Steigerwald Bardia Soltanzadeh Aritra Sarkar Cecilia C. Morgenstern Richard J. Staples Babak Borhan 《Chemical science》2021,12(5):1834
Intermolecular asymmetric haloamination reactions are challenging due to the inherently high halenium affinity (HalA) of the nitrogen atom, which often leads to N-halogenated products as a kinetic trap. To circumvent this issue, acetonitrile, possessing a low HalA, was used as the nucleophile in the catalytic asymmetric Ritter-type chloroamidation of allyl-amides. This method is compatible with Z and E alkenes with both alkyl and aromatic substitution. Mild acidic workup reveals the 1,2-chloroamide products with enantiomeric excess greater than 95% for many examples. We also report the successful use of the sulfonamide chlorenium reagent dichloramine-T in this chlorenium-initiated catalytic asymmetric Ritter-type reaction. Facile modifications lead to chiral imidazoline, guanidine, and orthogonally protected 1,2,3 chiral tri-amines.Intermolecular haloamination reactions are challenging due to the high halenium affinity of the nitrogen atom. This is circumvented by using acetonitrile as an attenuated nucleophile, resulting in an enantioselective halo-Ritter reaction. 相似文献