Description of the molecular mechanism of cooperativity in human hemoglobin cannot be limited to a first-order free energy coupling concept

Biochemistry ◽  
1988 ◽  
Vol 27 (2) ◽  
pp. 833-837 ◽  
Author(s):  
Michael L. Johnson
Keyword(s):  
Free Energy ◽  
Molecular Mechanism ◽  
Energy Coupling ◽  
Human Hemoglobin ◽  
First Order

TEMPERATURE DEPENDENCE OF SURFACE TENSION OF LIQUID CRYSTALS AT THE PHASE TRANSITION

1995 ◽  
Vol 09 (03n04) ◽  
pp. 237-242 ◽  
Author(s):  
R. MOLDOVAN ◽  
M. TINTARU ◽  
T. BEICA ◽  
S. FRUNZA ◽  
D. N. STOENESCU
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Surface Tension ◽  
Free Energy ◽  
Surface Layer ◽  
Order Parameter ◽  
Unit Area ◽  
Negative Slope ◽  
First Order ◽  
First Order Transition

The surface tension is calculated as the excess of the free energy per unit area, due to the presence of a surface layer, using Landau–de Gennes expansions, in the hypothesis of a first order transition in the bulk and taking into account the dependence of the surface free energy from the surface tilt angle. The surface order parameter is calculated and surface-ordered phase above the phase transition temperature has been found. A variety of calculated surface tension versus temperature curves with a jump at the phase transition, with positive or negative slope, well describing the experimental data from literature, have been attained.

Physical origin underlying the prenucleation-cluster-mediated nonclassical nucleation pathways for calcium phosphate

2019 ◽  
Vol 21 (27) ◽  
pp. 14530-14540 ◽  
Author(s):  
Xiao Yang ◽  
Mingzhu Wang ◽  
Yang Yang ◽  
Beiliang Cui ◽  
Zhijun Xu ◽  
...  
Keyword(s):  
Free Energy ◽  
Phase Separation ◽  
Calcium Phosphate ◽  
Molecular Mechanism ◽  
Free Energy Calculations ◽  
Nucleation Process ◽  
Physical Origin ◽  
Energy Calculations

We employed free energy calculations to reveal the molecular mechanism underlying the non-classical nucleation process and phase separation for calcium phosphate.

scholarly journals EFFECTS OF STRAIN COUPLING AND MARGINAL DIMENSIONALITY IN THE NATURE OF PHASE TRANSITION IN QUANTUM PARAELECTRICS

2013 ◽  
Vol 27 (08) ◽  
pp. 1350028 ◽  
Author(s):  
NABYENDU DAS
Keyword(s):  
Free Energy ◽  
Critical Point ◽  
Finite Temperature ◽  
Order Parameter ◽  
Quantum Critical Point ◽  
Order Transition ◽  
Zero Temperature ◽  
First Order ◽  
Quantum Paraelectrics ◽  
First Order Transition

Here a recently observed weak first order transition in doped SrTiO 3 [Taniguchi, Itoh and Yagi, Phys. Rev. Lett.99, 017602 (2007)] is argued to be a consequence of the coupling between strain and order parameter fluctuations. Starting with a semi-microscopic action, and using renormalization group equations for vertices, we write the free energy of such a system. This fluctuation renormalized free energy is then used to discuss the possibility of first order transition at zero temperature as well as at finite temperature. An asymptotic analysis predicts small but a finite discontinuity in the order parameter near a mean field quantum critical point at zero temperature. In case of finite temperature transition, near quantum critical point such a possibility is found to be extremely weak. Results are in accord with some experimental findings on quantum paraelectrics such as SrTiO 3 and KTaO 3.

CHARACTERISTIC TEMPERATURES OF FIRST-ORDER FERROELECTRIC PHASE TRANSITION: EFFECTIVE FIELD APPROACH

2012 ◽  
Vol 02 (02) ◽  
pp. 1241007 ◽  
Author(s):  
C. L. WANG ◽  
C. ARAGÓ ◽  
M. I. MARQUÉS
Keyword(s):  
Free Energy ◽  
Phase Transitions ◽  
Helmholtz Free Energy ◽  
Ferroelectric Phase ◽  
Effective Field ◽  
Static Properties ◽  
Field Approach ◽  
First Order ◽  
Characteristic Temperatures ◽  
Ferroelectric Phase Transitions

The explicit expression of Helmholtz free energy has been obtained from the equation of state from effective field approach. From the Helmholtz free energy, four characteristic temperatures describing a first-order ferroelectric phase transitions have been determined. The physical meaning of coefficients in Landau-type free energy has been revealed by comparison with the expanding Helmholtz function. Temperature dependence of polarization under different bias, and hysteresis loops at different temperatures are presented and discussed. These results provide the basic understandings of the static properties of first-order ferroelectric phase transitions.

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