scholarly journals Casimir-Foucault interaction: Free energy and entropy at low temperature

2010 ◽  
Vol 82 (3) ◽  
Author(s):  
Francesco Intravaia ◽  
Simen Å. Ellingsen ◽  
Carsten Henkel
Keyword(s):  
Free Energy ◽  
Low Temperature ◽  
Interaction Free Energy

Conformational analysis of 1,4-disubstituted cyclohexanes. III. trans-1,4-Di(trifluoroacetoxy)cyclohexane

1969 ◽  
Vol 47 (3) ◽  
pp. 429-431 ◽  
Author(s):  
Gordon Wood ◽  
E. P. Woo ◽  
M. H. Miskow
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Free Energy ◽  
Magnetic Resonance ◽  
Low Temperature ◽  
Conformational Analysis ◽  
Integration Method ◽  
Standard Free Energy ◽  
Energy Difference ◽  
Free Energy Difference ◽  
Conformational Free Energy

By the low temperature nuclear magnetic resonance integration method the standard free energy difference between the diequatorial and the diaxial forms of 1-H,4-H-trans-1,4-di(trifluoroacetoxy)-cyclohexane-d8 was found to be 77 ± 5 cal/mole. The conformational free energy (−ΔG0) of the trifluoroacetoxy group in the monosubstituted cyclohexane was 485 ± 4 cal/mole at the same temperature. The non-additivity of the −ΔG0 values is discussed in terms of transannular electrostatic interaction.

Ion-Electron Interaction Contribution to the Helmholtz Free Energy for Fully Ionized Hydrogen Plasma

2012 ◽  
Vol 229-231 ◽  
pp. 991-994
Author(s):  
Xing Rong Zheng ◽  
Chun Ling Tian ◽  
Na Wu ◽  
Bo Wu ◽  
Xiao Bing Wang
Keyword(s):  
Free Energy ◽  
Low Temperature ◽  
Thermodynamic Properties ◽  
High Pressures ◽  
Helmholtz Free Energy ◽  
Hydrogen Plasma ◽  
Padé Approximant ◽  
Electron Interaction ◽  
Pade Approximant ◽  
Interaction Contribution

The Padé approximation is a very important description of thermodynamic properties of fully ionized hydrogen at high pressures and temperatures. By comparing of several reported Padé approximants via calculation of the ion-electron interaction contribution to the Helmholtz free energy of the fully ionized hydrogen plasma, we find that Padé approximant proposed by Stolzman gives an unphysical odd local minimal appears at low temperature( ), and gradually fade away with the increase of temperature, implying a prominent limit of low temperature. While Chabrier et al. developed a more reasonable Padé approximant for the contribution of ion-electron interaction on the Helmholtz free energy. Analyses on isotherm curves indicate that the thermodynamic properties of the ion-electron interaction contribution to the Helmholtz free energy described by the revised Padé approximant is very stable at all temperatures and pressures without any unphysical effects at low temperatures.

scholarly journals Ion Transport in Hydrodictyon africanum

1967 ◽  
Vol 50 (6) ◽  
pp. 1607-1625 ◽  
Author(s):  
J. A. Raven
Keyword(s):  
Free Energy ◽  
Low Temperature ◽  
Electrical Potential ◽  
Bathing Solution ◽  
Electrical Potential Difference ◽  
Energy Gradient ◽  
Na Efflux ◽  
K Concentration ◽  
Net Fluxes ◽  
External K

The concentrations of K, Na, and Cl in the cytoplasm and vacuole, the tracer fluxes of these ions into and out of the cenocyte, and the electrical potential difference between bathing solution and vacuole and cytoplasm, have been measured in Hydrodictyon africanum. If the ions were acted on solely by passive electrochemical forces, a net efflux of K and Cl and a net influx of Na would be expected. Tracer fluxes indicate a net influx of K and Cl and efflux of Na in the light; these net fluxes are consequently active, with an obligate link to metabolism. The effects of darkness and low temperature indicate that most of the tracer K and Cl influx and Na efflux are linked to metabolism, while the corresponding tracer fluxes in the direction of the free energy gradient are not. Ouabain specifically inhibits the metabolically linked portions of tracer K influx and Na efflux. Alterations in the external K concentration have similar effects on metabolically mediated K influx and Na efflux. It would appear that K influx and Na efflux are linked, at least in the light.

scholarly journals Low Temperature Expansion in the Lifshitz Formula

2014 ◽  
Vol 2014 ◽  
pp. 1-34 ◽  
Author(s):  
M. Bordag
Keyword(s):  
Free Energy ◽  
Low Temperature ◽  
Asymptotic Expansions ◽  
Casimir Effect ◽  
Basic Method ◽  
Temperature Expansion ◽  
Starting Point ◽  
Unified Description

The low temperature expansion of the free energy in a Casimir effect setup is considered in detail. The starting point is the Lifshitz formula in Matsubara representation and the basic method is its reformulation using the Abel-Plana formula making full use of the analytic properties. This provides a unified description of specific models. We rederive the known results and, in a number of cases, we are able to go beyond. We also discuss the cases with dissipation. It is an aim of the paper to give a coherent exposition of the asymptotic expansions forT→0. The paper includes the derivations and should provide a self-contained representation.

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