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Yakub E.S.,Odessa I I Mechnikov National University | Yakub L.N.,Odessa State Academy of Refrigeration
Fluid Phase Equilibria | Year: 2013

New model equation of state (EOS) for highly compressed polymerizing fluid is developed and calibrated on ab initio simulation data. The EOS was applied to the prediction of the fluid-fluid transition in strongly compressed nitrogen. Location of the fluid-fluid phase transition line and position of the critical point on it were estimated and compared with earlier predictions and experimental shock compression data. © 2012 Elsevier B.V.

Shvets V.T.,Odessa State Academy of Refrigeration
Journal of Experimental and Theoretical Physics | Year: 2013

The effective ion-ion interaction, free energy, pressure, and electric resistance of metallic liquid helium have been calculated in wide density and temperature ranges using perturbation theory in the electron-ion interaction potential. In the case of conduction electrons, the exchange interaction has been taken into account in the random-phase approximation and correlations have been taken into account in the local-field approximation. The solid-sphere model has been used for the nuclear subsystem. The diameter of these spheres is the only parameter of this theory. The diameter and density of the system at which the transition of helium from the singly ionized to doubly ionized state occurs have been estimated by analyzing the pair effective interaction between helium atoms. The case of doubly ionized helium atoms has been considered. Terms up to the third order of perturbation theory have been taken into account in the numerical calculations. The contribution of the third-order term is significant in all cases. The electric resistance and its temperature dependence for metallic helium are characteristic of simple divalent metals in the liquid state. The thermodynamic parameters - temperature and pressure densities-are within the ranges characteristic of the central regions of giant planets. This makes it possible to assume the existence of helium in the metallic state within the solar system. © 2013 Pleiades Publishing, Ltd.

Trotsenko A.V.,Odessa State Academy of Refrigeration
Russian Journal of Physical Chemistry A | Year: 2011

The finiteness and positive value of the slope of the saturation curve at the critical point according to its location in the region of a thermodynamic surface restricted by the curves of inversion and saturation are substantiated. It is shown that any two derivatives of the first order formed with respect to volume, internal energy, entropy, enthalpy, and the Helmholtz energy, one of which is taken at a fixed value of pressure and the other at a fixed value of temperature, are equal in the critical state. New sets of the critical conditions for a pure substance are obtained. © 2011 Pleiades Publishing, Ltd.

Solomitsky M.,Odessa State Academy of Refrigeration
Modern Problems of Radio Engineering, Telecommunications and Computer Science - Proceedings of the 11th International Conference, TCSET'2012 | Year: 2012

Approaches to the formal description of interaction between the convergent telecommunication network and environment are offered. © 2012 Lviv Polytechnic Natl Univ.

Shvets V.T.,Odessa State Academy of Refrigeration
JETP Letters | Year: 2012

The effective proton-proton interaction in metallic hydrogen has been calculated for various densities. In the potential of this interaction, which can be represented in the form of a series of perturbation theory in the electron-proton interaction, the second- and third-order terms are taken into account. The second-order term gives a comparatively shallow potential well with one minimum. The position of the minimum corresponds to the equilibrium mutual position of protons in metallic hydrogen. When the third-order term is additionally taken into account, the potential has two characteristic minima; the position of one of them corresponds to the distance between the protons in a hydrogen molecule. The depths of these potential wells depend on the density of the system. At fairly high densities, only the potential well corresponding to the equilibrium position of protons in the metallic phase holds in the proton-proton potential. Owing to the presence of two minima in the effective proton-proton potential, the density of hydrogen at the point of transition to the metallic state can be estimated. Analysis of the effective proton-proton interaction makes it also possible to estimate the possibility of the existence of metallic hydrogen in a stable state at quite low temperatures. © 2012 Pleiades Publishing, Ltd.

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