• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1667-1671
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• 2003

A computer program to calculate properties of nitrogen is developed. Procedures for the calculation is briefly discussed. The program calculates unknown thermodynamic properties fixing the state with two independent input properties. If input value by user is inappropriate, it displays an error message and replaces the input value with an appropriate one. In addition user can change units with easy. The program developed in this work can be utilized to calculate parameters required for the simulation and design of an equipment using nitrogen.

• Journal of Korea Foundry Society
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• v.25 no.1
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• pp.36-39
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• 2005

The thermodynamic analysis of deoxidation in molten coppyr by Fe has been made. Equilibrium oxygen solubility saturated with FeO in Cu-Fe-O system has been derived without and with consideration of the solute interaction between Fe and O. The derived relationship of oxygen contents with Fe has been compared with the experimental results done by Kulkarni and the minimum oxygen solubility could be predicted by a simple first order interaction method, Wagner model.

• Bulletin of the Korean Chemical Society
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• v.22 no.7
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• pp.663-668
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• 2001

Thermodynamic and electrical functions of aminophenol and anthranilic acid complexes with Mn(Ⅱ), Fe(Ⅱ), Co(Ⅱ), Ni(Ⅱ) and Cu(Ⅱ) were determined. ΔG°, ΔH° and ΔS° were calculated with the help of stability constant values at different temperatures. It was found that the complexing processes have an exothermic nature. The studied complexes behave like semiconductors. The conduction takes place according to hopping mechanism. To show the composition of complexes conductometric and photometric titrations, IR spectra, thermal analysis and X-ray diffraction techniques were employed.

• Journal of Mechanical Science and Technology
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• v.20 no.9
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• pp.1475-1482
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• 2006

Wet compression means the injection of water droplets into the compressor of gas turbines. This method decreases the compression work and increases the turbine output by decreasing the compressor exit temperature through the evaporation of water droplets inside the compressor. Researches on wet compression, up to now, have been focused on the thermodynamic analysis of wet compression where the decrease in exit flow temperature and compression work is demonstrated. This paper provides thermodynamic and aerodynamic analysis on wet compression in a centrifugal compressor for a microturbine. The meanline dry compression performance analysis of centrifugal compressor is coupled with the thermodynamic equation of wet compression to get the meanline performance of wet compression. The most influencing parameter in the analysis is the evaporative rate of water droplets. It is found that the impeller exit flow temperature and compression work decreases as the evaporative rate increases. And the exit flow angle decreases as the evaporative rate increases.

• BMB Reports
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• v.44 no.2
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• pp.102-106
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• 2011

Thermodynamic stability and refolding kinetics of firefly luciferase and three representative mutants with depletion of negative charge on a flexible loop via substitution of Glu by Arg (ER mutant) or Lys (EK mutant) as well as insertion of another Arg in ER mutants (ERR mutant) was investigated. According to thermodynamic studies, structural stability of ERR and ER mutants are enhanced compared to WT protein, whereas, these mutants become prone to aggregation at higher temperatures. Accordingly, it was concluded that enhanced structural stability of mutants depends on more compactness of folded state, whereas aggregation at higher temperatures in mutants is due to weakening of intermolecular repulsive electrostatic interactions and increase of intermolecular hydrophobic interactions. Kinetic results indicate that early events of protein folding are accelerated in mutants.

• Journal of Institute of Convergence Technology
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• v.2 no.2
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• pp.30-34
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• 2012

The SI thermochemical cycle process accomplishes water splitting through distinctive three chemical reactions. We focused on thermodynamic models applicable to the process. Recently, remarkable models based on the assumed ionic species have been developed to describe highly nonideal behavior on the liquid phase reactions. ElecNRTL models with ionic reactions were proposed in order to provide reliable process simulation results for phase equilibrium calculations in Section II and III. In this study, the current thermodynamic models of SI thermochemical cycle process were briefly described and the calculation results of the applied ElecNRTL models for phase equilibrium calculations were illustrated for binary systems.

• International Journal of Air-Conditioning and Refrigeration
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• v.12 no.4
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• pp.176-183
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• 2004

Systematic methods to calculate thermodynamic properties of carbon dioxide, HFC-134a and HCFC-22 are presented. First, application of a basic method to identify the saturation state with given temperature or pressure is attempted and the feasibility of auxil­iary equations is tested. Next, detailed procedures are suggested to tell a phase when tem­perature/pressure and another property are specified. Finally the Newton-Raphson method is applied to calculate unknown thermodynamic properties fixing the state with the two inde­pendent properties specified. The procedures described here are utilized to develop a computer program, which is used to find the relation between temperature and pressure with maximum isobaric heat capacity for super-critical carbon dioxide.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.112-117
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• 2000

A numerical study on natural convection in a vertical square cavity filled with a porous medium is carried out with Brinkman-Forchheimer-extended Darcy flow model, and the validity of local thermodynamic equilibrium assumption is studied. The local thermodynamic equilibrium refers to the state in which a single temperature can be used to describe a heat transfer process in a multiphase system. With this assumption, the analysis is greatly simplified because only one equation is needed to describe the heat transfer process. But prior to using this assumption, it is necessary to know in what conditions the assumption can be used. The numerical results of this study reveal that large temperature difference between fluid phase and solid phase exists near wall region, paticularily when the convection becomes dominant over conduction. And the influence of flow parameters such as fluid Rayleigh number, fluid Prandtl number, dimensionless particle diameter and conductivity ratio are investigated.

• Coupled systems mechanics
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• v.4 no.3
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• pp.237-249
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• 2015

In the gear meshing process, gear temperature field concerns the meshing surface friction, the friction heat depends on the contact pressure, the contact pressure is affected by the elastic deformation of gears and the temperature field caused by the thermal deformation, so the temperature field, stress field and displacement field should be mutual coupling. It is necessary to consider in meshing gear pair in the operation process of thermodynamic coupling contact stress (TCCS) and thermodynamic coupling deformation (TCD), and based on thermodynamic coupling analysis (TCA) of gear teeth deformation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.5
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• pp.389-396
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• 2003

Systematic methods to calculate thermodynamic properties of carbon dioxide, HFC-l34a and HCFC-22 are presented. First, application of a basic method to identify the saturation state with given temperature or pressure is attempted and the feasibility of auxiliary equations is tested. Next, detailed procedures are suggested to tell a phase when temperature/pressure and another property are specified. Finally Newton-Raphson method is applied to calculate unknown thermodynamic properties fixing the state with the two independent properties specified. The procedures described here are utilized to develop a computer program, which is used to find the relation between temperature and pressure with maximum isobaric heat capacity for super-critical carbon dioxide.