Study on specific heat capacity and thermal conductivity of uranium nitride

In this study, we have proposed an analytical method for calculating the specific heat capacity of uranium nitride nuclear material. The specific heat capacity results have obtained by the use of the Debye-Einstein approximation. The thermal conductivity of nuclear material has been obtained by using the experimental data of thermal diffusivity and the calculation results of specific heat capacity. This method shows that our results are satisfactory for the wide range temperature variations. The proposed approach can be easily applied to determine the thermodynamic properties of the other nuclear materials.

DARK ENERGY IN MODIFIED SUPERGRAVITY

We propose a supersymmetric extension of the dynamical dark energy function and the scalar (super)potential in [Formula: see text] supergravity. Our model is viable in the Einstein approximation, and also has an analytic (regular) scalar potential. The hidden sector responsible for spontaneous supersymmetry breaking is also given.

PRESSURE COEFFICIENT OF THE SUPERCONDUCTING TRANSITION TEMPERATURE IN THE STRONG COUPLING LIMIT

Pressure coefficient (β) of the superconducting transition temperature (T c ) for a two dimensional system is studied in presence of Coulomb interaction, using Eliashberg equation with the Einstein approximation for the phonon system, within the van Hove scenario. β is found to be high in the low-T c region and low in the high-T c region. β is positive in the underdoped region and becomes negative in the overdoped region. For a given value of Fermi energy, β increases in the underdoped region and decreases in the overdoped region with the increase of Coulomb repulsion.

THERMAL STABILITY OF AN ADSORBED ARRAY OF CHARGES IN THE EINSTEIN APPROXIMATION

For an infinite hexagonal array of ions adsorbed on a conducting plane of infinite extent, the thermal fluctuation from strict lattice ordering in the neighborhood of a given adion is considered. The ions are imaged in the uniform, conducting adsorbent and are assumed to move freely in the plane; they thus arrange themselves in a perfect hexagonal array at absolute zero temperature. By use of the accurate planar potential seen by one adion moving in the field arising from an infinite number of fixed hexagonally arrayed surrounding ions, the root-mean-square (r.m.s.) amplitude of planar vibration of the ion relative to its neighbors is approximately determined for several values of nearest neighbor distances between ions, r1. On the basis of these results, we find, for example, that for a distance, β, between the center of charge of an ion and the imaging plane of 3 Å, an ionic valence zv of unity, and an effective dielectric constant of ε, a hexagonal array with r1 = 15 Å is stable up to a temperature, T0, of approximately 1760/ε°K while one with r1 = 21 Å is stable up to about 760/ε°K. Results apply to adsorption from either a gas or liquid phase and, as well, to an array of real dipoles adsorbed on a nonconducting surface. The appropriate values for ε are of the order of 2 and 6, respectively, for adsorption from gas or from aqueous electrolytes. For various r1's, explicit expressions for T0 are obtained which depend on ε, β, and zv.