• Transactions of the Korean Society of Mechanical Engineers
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• 제14권5호
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• pp.1337-1348
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• 1990

Estimations of the thermodynamic properties are made for the selected binary non-azeotropic refrigerant mixtures including R13B1/R114, R22/R114, R12/R114, R152a/R114, R13B1/R152a and R13B1/R12 using the Peng-Robinson equation of state and mixing rules. In this study, we find that the binary interaction coefficients for the above mixtures have an effect upon the vapor-liquid equilibria and the thermodynamic properties. As the binary interaction coefficient becomes larger, the deviation from the idealized model, say, Raoult`s rule, is obvious. A correlation is proposed to relate the binary interaction coefficient to the difference between the dipole moments op each pure refrigerant. Vapor-liquid equilibrium are also accurately estimated using the binary interaction coefficient. Pressure-enthalpy and temperature-entropy relations are plotted for a certain composition ratio of each refrigerant mixture. Results show that the estimating method in this study can be applied to the investigation of the thermodynamic properties for the binary non-azeotropic refrigerant mixtures.

• Journal of the Korean Chemical Society
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• 제37권4호
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• pp.442-447
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• 1993

The thermodynamic parameters (${\Delta}$G, ${\Delta}$H and ${\Delta}$S) of lanthanides(III)-benzoylformate complexes in aqueous solution have been determined in the ionic medium of 0.1M $NaClO_4$ at 25$^{\circ}C$, using pH and enthalpy titration method. The stability constants of the lanthanide(III)-benzoylformate complexes (1 : 1) agree well with the general relationships for the bidentate ligands (e.g., log${\beta}_1$ vs. p$K_a$). Thermodynamic evidences show that the oxygen atom in ketone group is coordinated along with the carboxylate group. It is ascribed to the increasing charge density on the oxygen atom in ketone group due to the conjugation effect in the benzoylformate ligand. Thermodynamic results also indicate that the complexes are stabilized by the enthalpy effect caused by the ionic interaction of metal-oxygen bond as well as the entropy effect.

• Korean Journal of Materials Research
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• 제12권4호
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• pp.283-289
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• 2002

The E.M.F of the galvanic cell with fused salt was measured to determine the activities of zinc at 700-820K over the entire composition range of liquid Zn-Cd alloys. The cell used was as follows: (-) W ｜ Zn(pure) $Zn^{2+}(KCI-LiCl)$ ｜ Zn(in Zn-Cd alloy) ｜ W (+) The activities of zinc in the alloys showed positive deviation from Raoult's law over the entire composition range. The activity of cadmium and some thermodynamic functions such as Gibbs free energy, enthalpy, entropy were derived from the results by the thermodynamic relationship. The comparison of the results and the literature data was made. The liquid Zn-Cd alloy is found to be close to the regular solution. The concentration fluctuations in long wavelength limit, $S_{cc}(o)$, in the liquid alloy was calculated from the results.

• Journal of the Korean Electrochemical Society
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• 제5권2호
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• pp.79-85
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• 2002

The present article is concerned with the application of the Monte Carlo simulation to electrochemistry of lithium intercalation from the thermodynamic view point. This article first introduced the fundamental concepts of the ensembles, and Ising and lattice gas models in statistical thermodynamics for the Monte Carlo simulation in brief. Finally the Monte Carlo method based upon the lattice gas model was employed to analyse thermodynamics of the lithium intercalation into the transition metal oxides. Especially we dealt with the thermodynamic properties as the electrode potential curve and the partial molar internal energy and entropy of lithium ion in the case of the $LiMn_2O_4$ electrode, and consequently confirmed the utility of the Monte Carlo method in the field of electrochemistry of the lithium intercalation.

• Journal of the Korean Chemical Society
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• 제15권3호
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• pp.133-145
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• 1971

A method of theoretical calculation of the thermodynamic properties for liquid-vapor interface of binary solution is developed according to the transient state theory of significant liquid structure. The surface tensions, the adsorbed amounts at the liquid-vapor interface and the activity coefficients of the components for the solutions of $C_6H_{12}-C_6H_6$ $CCI_4-C_6H_6$, $CHCl_3-C_6H_6$, $CHCl_3-CCl_4$, $CCl_4-CS_2$ are calculated through the full ranges of the compositions.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.150.1-150.1
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• 2011

Structure-II hydrate has been highlighted due to its higher gas storage capacity and favorable thermodynamic conditions. In this study, we introduce a new structure-II hydrate former, tert-butyl hydroperoxide (TBHP) and confirm the structural characteristics through High-Resolution Powder Diffraction (HRPD), $^{13}C$ solide-state NMR and Ramanspectroscopy. Here,we also investigated the thermodynamic stability of binary(TBHP+gaseous) clathrate hydrates. The experimental data were generated using an isochoric pressure-search method. The dissociation data for (TBHP +gaseous) clathrate hydrates are compared with the other hydrocarbon hydrate and pure gaseous hydrate.

• Transactions of the Korean Society of Mechanical Engineers B
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• 제33권3호
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• pp.201-206
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• 2009

The focus of this work is placed on the analysis of the mixture formation process under the evaporative diesel-free spray conditions. In order to examine homogeneity of mixture within the vapor phase region of the injected spray, image analysis was carried out based on the entropy of statistical thermodynamics. As an experimental parameter, the injection pressure and ambient gas density were selected, and effects of the injection pressure and density variation of ambient gas on the mixture formation process in the evaporative diesel spray were investigated. In the case of application of the thermodynamic entropy analysis to evaporative diesel spray, the value of the dimensionless entropy always increases with increase in time from injection start. Consequently, the dimensionless entropy in the case of the higher injection pressure is higher than that of lower injection pressure during initial injection period.

• Proceedings of the Korean Magnestics Society Conference
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• 한국자기학회 2012년도 자성 및 자성재료 국제학술대회
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• pp.130-131
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• 2012

In this study, the thermodynamic and magnetic properties of alloying element substituted B2 FeAl systems have been investigated using the all-electron FLAPW method based on the GGA. It was shown that the important changes take place in the structural properties as well as in the magnetism when alloying element is substituted by Fe or Al site in B2 FeAl. Detailed discussion on the thermodynamic and magnetic properties and electronic structure of these intermetallic compounds will be given.

• Journal of the Korean Chemical Society
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• 제43권3호
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• pp.251-256
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• 1999

Viscosities of toluene were experimentally determined by the falling-ball method at several temperatures and pressures to investigate the pressure and temperature dependence of the viscosity of toluene. With the shear stress of the viscous flow of toluene, the shear free energy, the shear entropy, and the shear enthalpy were defined to discuss the variations of the shear thermodynamic properties with pressure. The effect of temperature and pressure on the shear thermodynamic properties obtained experimentally can be explained by means of the molecular thermal agitation due to temperature incleasing and the steric effect of the closed molecules of to Iuene due to pressure elevation.

• The Transactions of the Korean Institute of Electrical Engineers
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• 제45권3호
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• pp.415-425
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• 1996

This study presents an analytical method of solving the behaviors of arc plasma in a nozzle constricting transferred-type torch and purposes to obtain the basic data for the design of a plasma torch, which can be obtained from the temperature, pressure, velocities and voltage distributions. We have to solve some conservation equations simultaneously and need to know the exact thermal gas properties in order to obtain the correct behaviors of arc plasma. It is also necessary to give the relevant physical or geometric boundary conditions. For the simplicity of analysis, we assumed that (a) the plasma flow is laminar, (b)the local thermodynamic equilibrium, i.e. LTE, prevails over the entire arc column region. The electrode sheath effects were neglected and the nozzle area was excluded from the analysis by assuming that the current flow into the nozzle is zero. We solved the momentum transfer equation including the self-magnetic pinch effect, and obtained the temperature distribution from the energy conservation equation. From this temperature, we could get arc voltage distribution. (author). refs., figs., tabs.