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91.
S. K. Maurya Y. K. Gupta Saibal Ray Debabrata Deb 《The European Physical Journal C - Particles and Fields》2017,77(1):45
In the present study we search for a new stellar model with spherically symmetric matter and a charged distribution in a general relativistic framework. The model represents a compact star of embedding class 1. The solutions obtained here are general in nature, having the following two features: first of all, the metric becomes flat and also the expressions for the pressure, energy density, and electric charge become zero in all the cases if we consider the constant \(A=0\), which shows that our solutions represent the so-called ‘electromagnetic mass model’ [17], and, secondly, the metric function \(\nu (r)\), for the limit n tending to infinity, converts to \(\nu (r)=C{r}^{2}+ ln~B\), which is the same as considered by Maurya et al. [11]. We have investigated several physical aspects of the model and find that all the features are acceptable within the requirements of contemporary theoretical studies and observational evidence. 相似文献
92.
Ram Narayan Deb 《Brazilian Journal of Physics》2017,47(2):107-121
We propose a total measure of multi-particle quantum correlation in a system of N two-level atoms (N qubits). We construct a parameter that encompasses all possible quantum correlations among N two-level atoms in arbitrary symmetric pure states and define its numerical value to be the total measure of the net atom-atom correlations. We use that parameter to quantify the total quantum correlations in atomic Schrödinger cat states, which are generated by the dispersive interaction in a cavity. We study the variation of the net amount of quantum correlation as we vary the number of atoms from N=2 to N=100 and obtain some interesting results. We also study the variation of the net correlation, for fixed interaction time, as we increase the number of atoms in the excited state of the initial system, and notice some interesting features. We also observe the behaviour of the net quantum correlation as we continuously increase the interaction time, for the general state of N two-level atoms in a dispersive cavity. 相似文献
93.
Dynamics of electronic motion in hydrogen atom under parallel strong oscillating magnetic field and intense laser fields
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M. Sadhukhan Amlan K. Roy P. K. Panigrahi B. M. Deb 《International journal of quantum chemistry》2016,116(5):377-387
The mechanism of ionization of an H atom interacting with intense laser electric fields is altered when a strong, oscillating magnetic field is applied along a direction parallel to the laser field. In this first study, these two strongly nonperturbative situations have been combined together and the corresponding time‐dependent (TD) Schrödinger equation has been numerically solved without using any basis set. The electric field arising out of the magnetic field and the magnetic field arising out of the laser electric field are found to be negligibly small, thereby not affecting the results. There are two main, apparently counter‐intuitive results from this study of parallel fields of the same frequency but different field strengths: (1) In presence of an oscillating magnetic field, the ionization rate due to the laser field diminishes, and (2) increasing the laser intensity, keeping the magnetic field strength the same, makes the electron density ionize with a lesser rate, in contrast to the situation with intense lasers in the absence of a strong TD magnetic field. © 2015 Wiley Periodicals, Inc. 相似文献
94.
Shyamolina Ghosh Deb Shankar Ray 《The European Physical Journal B - Condensed Matter and Complex Systems》2014,87(3):1-7
Using first-principles calculation, we have studied the properties of a series of M x Co1?x /Co(0001) (M = Pd, Pt) bimetallic surface alloys with atom M ratios from 0.25 to 1.0, then the effect of alloyed M metal on the properties of S adsorbed on these surfaces are discussed. Our calculations show that the alloying of metal Pd, Pt on Co(0001) weakens the S-M (M = Pd, Pt, Co) bond strength compared to monometallic surfaces and the site preference of sulfur atom is dependent on the alloyed metal M and its surface concentration. Moreover, bimetallic surface electronic structure modifications with and without sulfur are analyzed in comparison with clean Co(0001), and the correlation between the sulfur adsorption energy and the bimetallic surface d-band center is presented. 相似文献
95.
Ashwini Kumar Yadav Ravi kumar Akhilesh Gupta Barun Chatterjee Deb Mukhopadhyay H. G. Lele 《Heat and Mass Transfer》2014,50(6):737-746
In a nuclear reactor temperature rises drastically in fuel channels under loss of coolant accident due to failure of primary heat transportation system. Present investigation has been carried out to capture circumferential and axial temperature gradients during fully and partially voiding conditions in a fuel channel using 19 pin fuel element simulator. A series of experiments were carried out by supplying power to outer, middle and center rods of 19 pin fuel simulator in ratio of 1.4:1.1:1. The temperature at upper periphery of pressure tube (PT) was slightly higher than at bottom due to increase in local equivalent thermal conductivity from top to bottom of PT. To simulate fully voided conditions PT was pressurized at 2.0 MPa pressure with 17.5 kW power injection. Ballooning initiated from center and then propagates towards the ends and hence axial temperature difference has been observed along the length of PT. For asymmetric heating, upper eight rods of fuel simulator were activated and temperature difference up-to 250 °C has been observed from top to bottom periphery of PT. Such situation creates steep circumferential temperature gradient over PT and could lead to breaching of PT under high pressure. 相似文献
96.
Nath NC Sarker S Ahammad AJ Lee JJ 《Physical chemistry chemical physics : PCCP》2012,14(13):4333-4338
Three electrode structures with different spatial arrangements of carbon nanotubes (CNTs) in the mesoporous TiO(2) layer were employed in dye-sensitized solar cells to study the effect of surface states at the interface formed by the incorporation of CNTs. It was found that the decay of open circuit voltage (V(oc)) was significantly minimized by avoiding the direct contact of nanotubes to the conducting substrate by introducing a thin buffer layer of TiO(2) while maintaining the superior electron collection efficiency from the incorporation of nanotubes. 相似文献
97.
Biocompatible organic acids and citrate-stabilized gold nanoparticles were interacted with nisin to generate robust antimicrobial agents, which display archetypical nisin activity even at elevated pH. 相似文献
98.
In this paper an alternative approach for measurement of στ product for 4
F
3/2→4
I
11/2 transition of Nd3+ doped YVO4 crystal is reported. In this method a microchip laser is formed by keeping a small piece of the sample in plane-plane resonator
and a diode laser (808 nm) is used for pumping. The pump power induced thermal lensing effect is used to make the cavity stable.
The cavity mode area is estimated by measuring the thermal lens focal length at the threshold and the average pump area is
measured by Gaussian fit to the intensity profiles of the pump beam. The value of στ product of Nd:YVO4 crystal obtained by this method is within 10% of the reported values. The advantage of this method is that it is a simple
method for direct measurement of στ product of laser crystals. 相似文献
99.
Aniruddha Deb M. Itou Y. Sakurai N. Hiraoka N. Sakai 《Radiation Physics and Chemistry》2001,61(3-6):545-546
The spin density of Heusler alloy Co2FeGa, has been studied using the Compton scattering technique with 274 keV circularly polarized synchrotron radiation in the high energy inelastic scattering beamline (BL08W), at SPring-8, Japan. The magnetic Compton profiles along the two principal directions [1 1 0] and [1 1 1] were measured. The spin profiles shows a good agreement with our FLAPW-GGA results, where the theoretical results were based on the ferromagnetic ground state. The 3d spin moment at the Co and the Fe site was found to be in excellent agreement with the earlier reported neutron diffraction measurements. 相似文献
100.
Ramakumar K. L. Saxena M. K. Deb S. B. 《Journal of Thermal Analysis and Calorimetry》2001,66(2):387-397
Experimental evaluation of the procedures adopted for heat capacity measurements employing differential scanning calorimetry
(DSC) has been carried out by taking nickel and sapphire as test samples. Among the various methodologies reported in literature,
the absolute dual step method was chosen for this purpose due to its simplicity and minimum number of measurements required.
By proper temperature and heat flux calibration employing indium as reference, it was possible to obtain the calibration factor
independent of temperature. This was ascertained by analysing other pure metals namely Sn, Zn, Cd, and Pb and determining
their melting temperatures and heats of melting. Various operator- and sample-dependent parameters such as heating rate, sample
mass, the structure of the sample, reproducibility and repeatability in the measurements were investigated. Heat capacities
of both nickel and sapphire have been determined using the above method. Further, the heat capacity of nickel has also been
determined
using the widely employed three-step method taking sapphire as the heat flux calibration standard. Both methods yielded the
comparable heat capacity values for nickel. Based on the parameters investigated and their influence, it could be concluded
that reasonably precise and accurate heat capacity measurements are possible with DSC. One advantage of this method is the
elimination of a separate calibration run using a reference material of known heat capacity.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献