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141.
Debnath A Mukherjee B Ayappa KG Maiti PK Lin ST 《The Journal of chemical physics》2010,133(17):174704
We compute the entropy and transport properties of water in the hydration layer of dipalmitoylphosphatidylcholine bilayer by using a recently developed theoretical scheme [two-phase thermodynamic model, termed as 2PT method; S.-T. Lin et al., J. Chem. Phys. 119, 11792 (2003)] based on the translational and rotational velocity autocorrelation functions and their power spectra. The weights of translational and rotational power spectra shift from higher to lower frequency as one goes from the bilayer interface to the bulk. Water molecules near the bilayer head groups have substantially lower entropy (48.36 J/mol/K) than water molecules in the intermediate region (51.36 J/mol/K), which have again lower entropy than the molecules (60.52 J/mol/K) in bulk. Thus, the entropic contribution to the free energy change (TΔS) of transferring an interface water molecule to the bulk is 3.65 kJ/mol and of transferring intermediate water to the bulk is 2.75 kJ/mol at 300 K, which is to be compared with 6.03 kJ/mol for melting of ice at 273 K. The translational diffusion of water in the vicinity of the head groups is found to be in a subdiffusive regime and the rotational diffusion constant increases going away from the interface. This behavior is supported by the slower reorientational relaxation of the dipole vector and OH bond vector of interfacial water. The ratio of reorientational relaxation time for Legendre polynomials of order 1 and 2 is approximately 2 for interface, intermediate, and bulk water, indicating the presence of jump dynamics in these water molecules. 相似文献
142.
Rahul Ghosh Surajit Chattopadhyay Ujjal Debnath 《International Journal of Theoretical Physics》2012,51(2):589-603
This work is motivated by the work of Kim et al. (Mod. Phys. Lett. A 23:3049, 2008), which considered the equation of state parameter for the new agegraphic dark energy based on generalized uncertainty principle
coexisting with dark matter without interaction. In this work, we have considered the same dark energy interacting with dark
matter in emergent, intermediate and logamediate scenarios of the universe. Also, we have investigated the statefinder, kerk and lerk parameters in all three scenarios under
this interaction. The energy density and pressure for the new agegraphic dark energy based on generalized uncertainty principle
have been calculated and their behaviors have been investigated. The evolution of the equation of state parameter has been
analyzed in the interacting and non-interacting situations in all the three scenarios. The graphical analysis shows that the
dark energy behaves like quintessence era for logamediate expansion and phantom era for emergent and intermediate expansions
of the universe. 相似文献
143.
Ujjal Debnath Surajit Chattopadhyay Ibrar Hussain Mubasher Jamil Ratbay Myrzakulov 《The European Physical Journal C - Particles and Fields》2012,72(2):1875
In this work, we have considered the power-law correction of entropy on the horizon. If the flat FRW Universe is filled with
the n components fluid with interactions, the GSL of thermodynamics for apparent and event horizons have been investigated for
equilibrium and non-equilibrium cases. If we consider a small perturbation around the de Sitter spacetime, the general conditions
of the validity of GSL have been found. Also if a phantom dominated Universe has a pole-like type scale factor, the validity
of GSL has also been analyzed. Further we have obtained constraints on the power-law parameter α in the phantom and quintessence dominated regimes. Finally we obtain conditions under which GSL breaks down in a cosmological
background. 相似文献
144.
Piyali Bagchi Khatua Shuvendu Chakraborty Ujjal Debnath 《International Journal of Theoretical Physics》2012,51(2):405-417
In this work, we have considered dilaton dark energy model in Weyl-scaled induced gravitational theory in presence of barotropic
fluid. It is to be noted that the dilaton field behaves as a quintessence. Here we have discussed the role of dilaton dark
energy in modified gravity theories, namely f(R),f(T) and Hořava-Lifshitz gravities and analyzed the behavior of the dilaton field and the corresponding potential in respect
to these modified gravity theories instead of Einstein’s gravity. In f(R) and f(T) gravities, we have considered some particular forms of f(R) and f(T) and we have shown that the potentials always increase with the dilaton fields. But in Hořava-Lifshitz gravity, it has been
seen that the potential always decreases as dilation field increases. 相似文献
145.
Dinda B Debnath S Arima S Sato N Harigaya Y 《Chemical & pharmaceutical bulletin》2006,54(7):1030-1033
Four new iridoid glucosides, 5-dehydro-8-epi-adoxosidic acid, 5-dehydro-8-epi-mussaenoside, 10-O-dihydroferuloyldeacetyldaphylloside, and wendoside, together with one known iridoid glucoside, 8-epi-mussaenoside, beta-D-glucose, D-mannitol and beta-sitosterol have been isolated from the roots of Wendlandia tinctoria. On the basis of chemical and spectral analyses, the structures of new iridoid glucosides have been elucidated. 相似文献
146.
The total charge of the projectile spectator fragments, Qpf is taken as a measure of the degree of centrality of collision thus defining the collision geometry. In this paper the mean
multiplicities of the different charged secondaries emitted in the interaction of 24Mg-Em at 4.5A GeV have been investigated as a function of the total charge Qpf of the projectile spectator fragments. It has been observed that the average number of the produced particles, 〈Ns〉 and the heavily ionizing particles, 〈Nh> decreases exponentially with the increase of Qpf showing strong correlation with the geometry of the collision. An attempt has also been made to compare these results with
84Kr-Em interaction at 0.95A GeV. 相似文献
147.
Surajit Chattopadhyay Ujjal Debnath 《International Journal of Theoretical Physics》2010,49(7):1465-1480
The present work considers interaction between DBI-essence and other candidates of dark energies like modified Chaplygin gas,
hessence, tachyonic field, and new agegraphic dark energy. The potentials of the fields have been reconstructed under interaction
and their evolutions have been viewed against cosmic time t and scalar field φ. Equation of state parameters have also been obtained. The nature of potentials and the equation of state parameters of the
dark energies have been found graphically in presence of interaction (both small and large interaction). 相似文献
148.
Arvind Kumar A.K. Debnath S. Samanta D.K. Aswal S.K. Gupta J.V. Yakhmi 《Talanta》2010,82(4):1485-1489
We present room temperature chemiresistive gas sensing characteristics of drop casted sulphonated copper phthalocyanine (CuTsPc) films. It has been demonstrated that these films are highly selective to Cl2 and the sensitivity in the 5-2000 ppb range varies linearly between 65 and 625%. However, for concentrations ≥2000 ppb, the response becomes irreversible, which is found to be due to the chemical bond formation between Cl2 and SO3Na group of CuTsPc films. The X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) data confirms the oxidation of SO3Na group by Cl2 gas. 相似文献
149.
This paper deals with the exact solution of surface gravity waves in an ocean with irregular bed topography. In order to obtain water surface elevation and run-up of infra-gravity waves when the bed is either wavy or exponential, closed form solutions are obtained. Numerical computations indicate that when solitary wave or sinusoidal wave conditions are applied at the boundary, water surface elevation attains near Gaussian profile. 相似文献
150.
Tong Zhang M. Debnath S. K. Clowes W. R. Branford A. Bennett C. Roberts L. F. Cohen R. A. Stradling 《Physica E: Low-dimensional Systems and Nanostructures》2004,20(3-4):216
Both magneto-resistive sensors and spintronic hybrid semiconductor devices require thin epitaxial layers of high-mobility InSb. Here we study unintentionally doped InSb epilayers grown on semi-insulating GaAs(100) substrates by molecular-beam epitaxy. We have introduced an initial low-temperature growth step extending the work that the NTT group reported in 2000. We find significant improvement in the room temperature mobility for epilayer thickness between 60 and 300 nm. The importance of the initial growth step to the epilayer mobility performance is discussed. 相似文献