Superstructure orthorhombicII (OII) phase in polycrystalline samples of YBCOx was observed by using synchrotron in-situ high resolution powder diffraction (HRPD) techniques at 300˚C. Rietveld method (RM) refinement was employed to analyse the collected diffraction data under proper oxygen partial pressure atmospheres. Our study indicates that by oxygen uptake, the samples undergo structural pha...

The ferromagnetic Ising model on the Bethe lattice of degree k is considered in the presence of a dichotomous external random field fx= +a and the temperature T>0. We give a description of a part of the phase diagram of this model in the T-a. plane, where we are able to construct limiting Gibbs states and ground states. By comparison with the model with a constant external field we show that fo...

In this work, the melting point and the phase diagram of methanol is determined via computer simulations using the OPLS model. The three different solid structures that are found experimentally were considered. By computing the free energies of both the fluid phase and the three different solid structures (alpha, beta, gamma), the initial solid-solid and fluid-solid coexistence points were dete...

Phase diagram of the spin-1 quantum Heisenberg model with both exchange as well as single-ion anisotropy is constructed within the framework of pair approximation formulated as a variational procedure based on the Gibbs-Bogoliubov inequality. In this form adapted variational approach is used to obtain the results equivalent with the Oguchi’s pair approximation. It is shown that the single-ion a...

Phase diagram of the spin-1 quantum Heisenberg model with both exchange as well as single-ion anisotropy is constructed within the framework of pair approximation formulated as a variational procedure based on the Gibbs-Bogoliubov inequality. In this form adapted variational approach is used to obtain the results equivalent with the Oguchi’s pair approximation. It is shown that the single-ion a...

We study the equivalence of ensembles for stationary measures of interacting particle systems with two conserved quantities and unbounded local state space. The main motivation is a condensation transition in the zero-range process which has recently attracted attention. Establishing the equivalence of ensembles via convergence in specific relative entropy, we derive the phase diagram for the c...

The electroweak phase transition in the Two-Higgs-Doublet Model is investigated. Gibbs potential at a finite temperature computed with regard for one-loop plus ring diagram contributions. strong first-order satisfying Sakharov's baryogenesis conditions determined values of scalar field masses allowed by experimental data. relation between model parameters supplying to be first order derived. It...

We determine the phase diagram of several amphiphilic molecules as a function of the amphiphilic parameter alpha defined as the ratio of the volume of hydrophilic to hydrophobic segments using the Gibbs ensemble Monte Carlo method supplemented by configurational bias scheme. Specifically, we study amphiphilic molecules h(1)t(7), h(2)t(6), and h(3)t(5), for which alpha=0.14, 0.33, and 0.60 respe...

The phase behavior of both pure systems and binary mixtures has been widely studied by molecular simulation [1], using techniques such as the Gibbs ensemble [2], Gibbs-Duhem [3] or histogram reweighing [4] algorithms. The common aim of many of these investigations is to accurately predict the phase diagram using effective intermolecular potentials, most notable the Lennard-Jones potential. In c...