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1.
A self-consistent system of gravitational field with a binary mixture of perfect fluid and dark energy given by a cosmological
constant has been considered in Bianchi Type-V universe. The perfect fluid is chosen to be obeying either the equation of
state p=γρ with γ ε |0,1| or a van der Waals equation of state. The role of A-term in the evolution of the Bianchi Type-V universe has been
studied. 相似文献
2.
V. K. Chaubey A. Mishra 《Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences)》2017,52(1):1-7
In the present paper we study the Finslerian hypersurfaces of a Finsler space with a special (α, β) metric, and examine the hypersurfaces of this special metric as a hyperplane of first, second and third kinds. 相似文献
3.
This paper reports the simulative analyses to investigate the impact of different pulse shapes on DP-DQPSK modulation for high-spectral efficient DWDM transmission at 112 Gbps per channel. In the simulation model we have considered three different pulse shapes viz. NRZ, 50% duty cycle RZ (RZ50) and 67% duty cycle RZ (RZ67) in symbol-aligned and symbol-interleaved format. The analysis has been carried out for various linear and nonlinear system impairments where the pulse is subjected to degradation under the influence of amplified spontaneous emission (ASE) noise, group velocity dispersion (GVD), cross-phase modulation (XPM) and polarization mode dispersion (PMD) and thus, limiting the system performance. Results show that the RZ50 pulse shape for DP-DQPSK with symbol interleaving shows the maximum tolerance for the various system degradations in long haul DWDM transmission. Even the system based on the NRZ pulse shape can gain significant improvement from the symbol-interleaving. 相似文献
4.
The photo (PL) and electro (EL) luminescence in ZnS: MnLa and ZnS: La have been studied. The enhancement and quenching of
emission bands have been observed on the simultaneous application of sinusoidal field and photons. The wave shape, voltage,
frequency and temperature dependence of EL brightness have been reported. A study of the phosphorescence and thermoluminescence
of these phosphors is also carried out and it is observed that the trap-depth changes slowly with temperature and activator
concentration. An attempt has been made to calculate the trap depth by studying temperature dependence of EL brightness. The
results are reported and discussed. 相似文献
5.
Gutti Jogesh Babu Yogendra P. Chaubey 《Annals of the Institute of Statistical Mathematics》1996,48(1):75-88
This paper studies regression, where the reciprocal of the mean of a dependent variable is considered to be a linear function of the regressor variables, and the observations on the dependent variable are assumed to have an inverse Gaussian distribution. The large sample theory for the pseudo maximum likelihood estimators is available in the literature, only when the number of replications increase at a fixed rate. This is inadequate for many practical applications. This paper establishes consistency and derives the asymptotic distribution for the pseudo maximum likelihood estimators under very general conditions on the design points. This includes the case where the number of replications do not grow large, as well as the one where there are no replications. The bootstrap procedure for inference on the regression parameters is also investigated.Research supported in part by NSF Grant DMS-9208066.Research supported in part by NSERC of Canada. 相似文献
6.
R. Chaubey 《International Journal of Theoretical Physics》2013,52(4):1300-1308
The open anisotropic cosmological model of the early Universe is considered. Two interacting scalar fields with special form of potential energy are a source of matter fields. Analytic solutions for inflationary and scalaron stages are found. The exact solutions to the corresponding field equations are obtained in quadrature form. The cosmological parameters have been discussed in detail and it is also shown that the solutions tend asymptotically to isotropic Friedmann-Robertson-Walker cosmological model. 相似文献
7.
8.
Synthesis and stabilization of FeCo nanoparticles 总被引:1,自引:0,他引:1
Chaubey GS Barcena C Poudyal N Rong C Gao J Sun S Liu JP 《Journal of the American Chemical Society》2007,129(23):7214-7215
9.
R. Chaubey 《International Journal of Theoretical Physics》2009,48(4):952-960
We have studied the evolution of a homogeneous, anisotropic universe given by a Bianchi type-I cosmological model with modified
Chaplygin gas. We have assumed that the equation of state of this modified model is valid from the radiation era to the ΛCMD
model. We have used state-finder parameters in characterizing different phase of the model. 相似文献
10.
Dark energy with the usually used equation of state p=γρ, where γ=const<0 is hydrodynamically unstable. To overcome this drawback we consider the cosmology of a perfect fluid with a linear equation
of state of a more general form p=α(ρ−ρ
0), where the constants α and ρ
0 are free parameters. The anisotropic Bianchi type-I cosmological model filled with dark energy has been considered. A generalized
equation of state for the dark energy component of the universe has been used. The exact solutions to the corresponding Einstein
field equations and the statefinder diagnostic pair i.e. {r,s} parameters have been obtained in three interesting cases (i) when ρ
Λ>0 and A>0 (ii) when ρ
Λ>0 and A<0 and (iii) when ρ
Λ<0 and A>0 at the singularities i.e. t→0 and t→±∞. 相似文献