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An exact diagonalization calculation of the t-J model on 2D square cluster has been studied for the ground state properties of HTSC. Effect of next-nearest-neighbour hopping and magnetic (both antiferromagnetic and ferromagnetic) interaction on dx2−y2-wave pairing has been shown. Relative strength of the next-nearest-neighbour interaction with respect to that of near-neighbour interaction for...
KALI-1000 pulse power system has been used to generate single pulse nanosecond duration high-power microwaves (HPM) from a virtual cathode oscillator (VIRCATOR) device. HPM power measurements were carried out using a transmitting-receiving system in the presence of intense high frequency (a few MHz) electromagnetic noise. Initially, the diode detector output signal could not be recorded due to the...
We present a new approach to Hamilton’s theory of turns for the groups SO(3) and SU(2) which renders their properties, in particular their composition law, nearly trivial and immediately evident upon inspection. We show that the entire construction can be based on binary rotations rather than mirror reflections.
In this paper we investigate two-dimensional (2D) Rayleigh-Bénard convection using direct numerical simulation in Boussinesq fluids with Prandtl number P = 6.8 confined between thermally conducting plates. We show through the simulation that in a small range of reduced Rayleigh number r (770 < r < 890) the 2D rolls move chaotically in a direction normal to the roll axis. The lateral shift of...
This paper describes the effect of 24 MeV proton irradiation on the electrical characteristics of a pnp bipolar junction transistor 2N 2905A. I-V, C-V and DLTS measurements are carried out to characterize the transistor before and after irradiation. The properties of deep level defects observed in the bulk of the transistor are investigated by analysing the DLTS data. Two minority carrier levels,...
The free energy of a quark-gluon plasma fireball in the hadronic medium is calculated in the Ramanathan et al statistical model after incorporating the effect of curvature. The result with the inclusion of curvature is found to produce significant improvements in all the parameters we calculated with respect to the earlier results. The surface tension with this curvature effect is found to be 0.17...
We study continuum percolation of overlapping circular discs of two sizes. We propose a phenomenological scaling equation for the increase in the effective size of the larger discs due to the presence of the smaller discs. The critical percolation threshold as a function of the ratio of sizes of discs, for different values of the relative areal densities of two discs, can be described in terms of...
A numerical study is presented to investigate the role of solitons in the electronic states of double-stranded DNA (dsDNA) molecule in the metal/DNA/metal system. Based on tight-binding Hamiltonian model and within the framework of a generalized Green’s function technique, we consider a ladder model for poly(dG)-poly(dC) DNA molecule containing M cells with four sites (two base pair sites and two...
GaN and AlGaN epitaxial layers are grown by a metalorganic chemical vapour deposition (MOCVD) system. The crystalline quality of these epitaxially grown layers is studied by different characterization techniques. PL measurements indicate band edge emission peak at 363.8 nm and 312 nm for GaN and AlGaN layers respectively. High resolution XRD (HRXRD) peaks show FWHM of 272 and 296 arcsec for the (0...
Using Lie algebraic techniques and simpler expressions of the matrix elements of Majorana and Casimir operators given by us, we obtain an effective Hamiltonian operator which conveniently describes stretching vibrations of biomolecules. For a copper tetramesityl porphyrin molecule, the higher excited vibrational levels are calculated by applying the U(2) algebraic approach.
The dynamic structure factor S(q, ω) of a harmonically trapped Bose gas has been calculated well above the Bose-Einstein condensation temperature by treating the gas cloud as a canonical ensemble of non-interacting classical particles. The static structure factor is found to vanish s8 q2 in the long-wavelength limit. We also incorporate a relaxation mechanism phenomenologically by including a stochastic...
The branching ratio for Bs → ℓ+ℓ−γ mode is of the same order as Bs → ℓ+ℓ−, since there is no helicity suppression in the 3-body decay mode. New Physics beyond Standard Model may affect these rates favourably for experimental observation at LHC and simultaneous measurements of the modes Bs...
Potential energy curves of various electronic states of COn+ (0 ≤ n ≤ 6) are generated at MRCI/CASSCF level using cc-pvQZ basis set and the results are compared with available experimental and theoretical data.
The bifurcation theory of dynamical systems is applied to an integrable nonlinear wave equation. As a result, it is pointed out that the solitary waves of this equation evolve from bell-shaped solitary waves to W/M-shaped solitary waves when wave speed passes certain critical wave speed. Under different parameter conditions, all exact explicit parametric representations of solitary wave solutions...
In this paper, we present results of our calculations on the effects of next-to-nearest-neighbour boson hopping (t′) energy on Bose-Einstein condensation in cubic lattices. We consider both non-interacting and repulsively interacting bosons moving in the lowest Bloch band. The interacting bosons are studied using Bogoliubov method. We find that the Bose condensation temperature is enhanced by increasing...
In this paper, we have provided an overview of cosmic ray effects on terrestrial processes such as electrical properties, global electric circuit, lightning, cloud formation, cloud coverage, atmospheric temperature, space weather phenomena, climate, etc. It is suggested that cosmic rays control short-term and long-term variations in climate. There are many basic phenomena which need further study...
Thermal effects of a double-end-pumped cubic Nd:YVO4 laser crystal are investigated in this paper. A detailed analysis of temperature distribution and thermal stress in cubic crystal with circular shape pumping is discussed. It has been shown that by considering the total input powers as constant, the double-end-pumped configurations with equal pump power can be considered as having a minimum thermal...
Chaotic synchronization of two directly modulated semiconductor lasers with negative delayed optoelectronic feedback is investigated and this scheme is found to be useful for efficient bidirectional communication between the lasers. A symmetric bidirectional coupling is identified as a suitable method for isochronal synchronization of such lasers. The optimum values of coupling and feedback strength...
We have measured near normal incidence far-infrared (FIR) reflectivity spectra of a single crystal of TbMnO3 from 10 K to 300 K in the spectral range of 50 cm−1–700 cm−1. Fifteen transverse optic (TO) and longitudinal optic (LO) modes are identified in the imaginary part of the dielectric function ɛ2(ω) and energy loss function Im(−1/ɛ(ω)), respectively. Some of the observed phonon modes show anomalous...
Electrical properties of SiO2 grown on the Si-face of the epitaxial 4H-SiC substrate by wet thermal oxidation technique have been experimentally investigated in metal oxide-silicon carbide (MOSiC) structure with varying oxide thicknesses employing Poole-Frenkel (P-F) conduction mechanism. The quality of SiO2 with increasing thickness in MOSiC structure has been analysed on the basis of variation in...
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