On reconstitutive phase transitions and the jump of the chemical potential

Analysis ◽  
2008 ◽  
Vol 28 (1) ◽  
Author(s):  
Thomas Blesgen
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Weak Solutions ◽  
Transition Layer ◽  
Chemical Potential ◽  
Sharp Interface ◽  
Free Energies ◽  
Diffusion In Solids ◽  
Existence Of Weak Solutions ◽  
Two Phases

This article studies diffusion in solids in the case of two phases under isothermal conditions where due to plastic effects the number of vacancies changes when crossing a transition layer, i.e. a reconstitutive phase transition. A segregation model is derived and the equations are studied in the limit of a sharp interface. A Gibbs–Thomson law is derived and it is shown that the vacancy component of the chemical potential jumps across the transition layer thereby explaining recent experimental observations. The thermodynamic correctness of the model is shown as well as the existence of weak solutions with logarithmic free energies.

PHASE TRANSITION PATTERNS OF NUCLEAR MATTER BASED ON EXTENDED LINEAR SIGMA MODEL

2013 ◽  
Vol 22 (11) ◽  
pp. 1350077 ◽  
Author(s):  
TRAN HUU PHAT ◽  
NGUYEN TUAN ANH ◽  
PHUNG THI THU HA
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Nuclear Matter ◽  
Degrees Of Freedom ◽  
Sigma Model ◽  
Chemical Potential ◽  
Linear Sigma Model ◽  
Baryon Chemical Potential ◽  
Chiral Phase ◽  
The Relationship

We study systematically various types of phase transitions in nuclear matter at finite temperature T and baryon chemical potential μ based on the extended linear sigma model with nucleon degrees of freedom. It is shown that there are three types of phase transitions in nuclear matter: the chiral symmetry nonrestoration (SNR) at high temperature, the well-known liquid–gas (LG) phase transition at sub-saturation density and the Lifshitz phase transition (LPT) from the fully-gapped state to the state with Fermi surface. Their phase diagrams are established in the (T, μ)-plane and their physical properties are investigated in detail. The relationship between the chiral phase transition and the LG phase transition in nuclear matter is discussed.

WEIGHT RATIO FIXING AT FIRST ORDER PHASE TRANSITIONS

1992 ◽  
Vol 03 (05) ◽  
pp. 1109-1117
Author(s):  
THOMAS LIPPERT ◽  
KLAUS SCHILLING ◽  
PEER UEBERHOLZ ◽  
GYAN BHANOT
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Weight Ratio ◽  
Phenomenological Method ◽  
Reliable Determination ◽  
First Order ◽  
First Order Phase Transition ◽  
Two Phases ◽  
First Order Phase

The presence of strong metastabilities in computer simulations of models showing a first order phase transition hinders a reliable determination of the weight ratio between the two phases. We discuss a new phenomenological method which allows an accurate fixing of the weight ratio using the standard multihistogram procedure.

Pressure induced wurtzite-to-zinc blende phase transition in ZnO at finite temperature

2008 ◽  
Vol 23 (12) ◽  
pp. 3347-3352 ◽  
Author(s):  
Yaping Wu ◽  
Junyong Kang ◽  
Feng Liu
Keyword(s):  
Phase Transition ◽  
Energy Barrier ◽  
Energy Difference ◽  
Vibrational Entropy ◽  
Free Energies ◽  
Zinc Blende ◽  
Face Centered ◽  
Two Phases ◽  
Dynamics Simulations ◽  
Increasing Temperature

We predict a possible phase transition of ZnO from wurtzite to zinc blende structure using first-principles molecular-dynamics simulations. By calculating the Gibbs free energies of the two phases as a function of temperature and hydrostatic pressure, we show that their energy difference decreases continuously with increasing temperature and pressure, and the vibrational entropy plays an important role on the location of the phase transition point. At 300 K, the phase transition is expected to occur at a pressure lower than 30 GPa with an activation energy barrier of 0.386 eV/atom. The transition path was also simulated, along which the system goes through a transient face-centered orthorhombic structure to overcome the energy barrier. Our theory results may be valuable for stabilizating the zinc blende ZnO in experiment.

EXISTENCE OF SOLUTIONS WITH MOVING PHASE BOUNDARIES IN THERMOELASTICITY

2008 ◽  
Vol 05 (03) ◽  
pp. 589-611 ◽  
Author(s):  
HARUMI HATTORI
Keyword(s):  
Phase Transitions ◽  
Euler Equations ◽  
Weak Solutions ◽  
Existence Of Solutions ◽  
Entropy Condition ◽  
Phase Boundaries ◽  
Kinetic Relation ◽  
Two Phase ◽  
Existence Of Weak Solutions ◽  
Dynamic Phase

We discuss the existence of weak solutions with moving phase boundaries in thermoelasticity related to dynamic phase transitions. One of the goals is to study the dynamical consequence of the stable and metastable states defined in this paper. We use the entropy condition and the kinetic relation as the main admissibility criteria to study the above goals for the Euler equations with nonmonotone constitutive relation. We discuss the case where there are two noninteracting phase boundaries moving in the opposite directions. A modification to treat the case where the two phase boundaries collide is also discussed.

Convection in a fluid with two phases

1971 ◽  
Vol 46 (4) ◽  
pp. 801-812 ◽  
Author(s):  
F. H. Busse ◽  
G. Schubert
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Gravitational Instability ◽  
Fluid Layer ◽  
Dense Phase ◽  
Opposite Case ◽  
Two Phases ◽  
Horizontal Fluid Layer

The gravitational instability of a horizontal fluid layer with a univariant phase transition is considered. It is found that the layer can be unstable even when the less dense phase lies above the dense phase and can be stable in the opposite case. Applications of the theory to convection with phase transitions in astrophysical and geophysical problems are briefly discussed.

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