• Journal of Magnetics
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• v.22 no.1
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• pp.1-6
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• 2017

Magnetic properties of CoPt nanoparticles (average size = 2.1 nm) encapsulated in synthesized protein shell have been investigated with SQUID (Superconducting Quantum Interference Device) magnetometer and analyzed by the recently developed non-equilibrium magnetization calculation by our group [T. H. Lee et al., Phys. Rev. B 90, 184411 (2014)]. Field dependence of magnetization measured at 2 K was successfully analyzed with modified Langevin function. In addition, small hysteresis loops having the coercive field of 890 Oe were observed at 2 K. Temperature dependence of magnetization has been measured with zero field cooled (ZFC) and field cooled (FC) protocol with slightly modified sequence in accordance with non-equilibrium magnetization calculation. The analysis on the M vs. T data revealed that the anisotropy energy barrier distribution is found to be very different from the log-normal distribution found in a size distribution. Zero temperature coercive field and Bloch coefficient have also been extracted from the analysis and the validity of those values is checked.

• Journal of applied mathematics & informatics
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• v.3 no.2
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• pp.149-156
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• 1996

We discuss sensitivity of equilibrium points in bimatrix games depending on small variances (perturbations) of data. Applying implicit function theorem to a linear complementarity problem which is equivalent to the bimatrix game we investigate sensitivity of equi-librium points with respect to the perturbation of parameters in the game. Namely we provide the calculation of equilibrium points deriva-tives with respect to the parameters.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.10
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• pp.80-89
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• 1996

This paper proposes a new COA (center of area) defuzzifier that is working in the accurate and fast manner. The proposed COA defuzzifier involves both membership values and the spans of membership functions in clauclating a crisp value. In additon, it avoid division by replacing the COA calculation with the searching of the momentum equilibrium point. The moment equilibrium point is searched in the coarse-to-fine manner such that the moment computing points during the coarse searching are moved in the interval of fuzzy terms until they are reached at two adjacent fuzzy terms searching method accerlates the finding of the moment equilibrium point by O(M) mazimally when compared iwth the equal interval searching method of ruitz. In order to verify the accuracy of the proposed COA defuzzifier, the crisp values obtained form the proposed coarse-to-fine searching are compared with the precise crisp values from the arithmetic calculation. Application to the truck backer-upper control problem of the proposed COA defuzzifier is presented. The control performance is compared with that of the conventional COA defuzzifier in tems of the average tracing distance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.65-69
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• 2002

Unsteady vaporization of a droplet quiescent in a high pressure environment are studied with emphasis placed oil the modeling of equilibrium at vapor-liquid interface. Complete set of conservation equations for liquid and gas phases is numerically time integrated. Vapor-liquid interfacial thermodynamics are solved by f]ash equilibrium calculation method. The model was proper]y validated with experiment and the improvement in the solution accuracy was made. Vaporization of n-pentane fuel droplet in nitrogen background gas is examined. Effects of ambient gas solubility, property variation, transient diffusion, and multicomponent transport on the droplet vaporization are investigated systematically. High-pressure effects on the droplet vaporization is examined and discussed.

• 한국연소학회:학술대회논문집
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• 2001.06a
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• pp.106-118
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• 2001

A rigorous study of single droplet vaporization under quiescent high pressure atmosphere is attempted adopting method of flash evaporation calculation for vapor-liquid equilibrium. Results due to flash method shows excellent agreement with measurement. Also shown is the present model fairly capable of depicting transients of droplet vaporization under high pressure environment, such as ambient gas solubility, property variation, and multicomponent transports. Systematic treatment of these effects with emphasis on vapor-liquid phase equilibrium revealed; conventional treatment for subcritical droplet vaporization, such as $d^2$-law, leads to erroneous prediction of droplet history, augmented gas solubility is significant under supercritical pressure, and vaporization rate proportionally increase with pressure.

• Journal of Industrial Technology
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• v.5
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• pp.73-79
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• 1985

Thermodynamic calculation for the CVD of SiC from methyltrichlorosilane(MTS) was done in some range of deposition condition to identify optimum condition. The results show that the most considerable chemical species are chloride and chlorosilane for silicon source and methane and acetylene for carbon source. In order to yield single phase ${\beta}$-SiC it is believed that optimum temperature range is between 1500 and $1700^{\circ}k$. With increasing temperature, stable phase is changed from Si+SiC phase to C+SiC phase. It is believed because equilibrium concentration of silicon source decrease and equilibrium concentration of carbon source increases with increasing temperature.

• Structural Engineering and Mechanics
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• v.41 no.3
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• pp.339-348
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• 2012

The slope stability analysis is usually done using the methods of calculation to rupture. The problem lies in determining the critical failure surface and the corresponding factor of safety (FOS). To evaluate the slope stability by a method of limit equilibrium, there are linear and nonlinear methods. The linear methods are direct methods of calculation of FOS but nonlinear methods require an iterative process. The nonlinear simplified Bishop method's is popular because it can quickly calculate FOS for different slopes. This paper concerns the use of inverse analysis by genetic algorithm (GA) to find out the factor of safety for the slopes using the Bishop simplified method. The analysis is formulated to solve the nonlinear equilibrium equation and find the critical failure surface and the corresponding safety factor. The results obtained by this approach compared with those available in literature illustrate the effectiveness of this inverse method.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.4
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• pp.483-491
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• 2016

A simple aerodynamic calculation program for high Mach number flow is developed by combining the modified Newtonian method with Tannehill's curve fits for the thermodynamic properties of air in equilibrium state. Aerodynamic characteristics for a parabolic nose are predicted and compared with CFD(Computational Fluid Dynamics) analysis results. Comparison shows good agreements, and the developed program is expected to be a practical tool for slender body aerodynamic calculation for high Mach number flow.

• Journal of The Korean Astronomical Society
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• v.11 no.1
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• pp.55-58
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• 1978

An extensive molecular equilibrium calculation has been performed under sunspot conditions in order to resolve the current dispute on the presence of $C_2$ lines in the spectrum of sunspots. Equilibrium abundance of $C_2$ has been computed under the conditions of umbral cores, umbrae and the normal photosphere. As the results, it is found that the umbral cores yield unfavorable environment for $C_2$ formation. It is concluded that $C_2$ molecular lines are not likely tn be observed in the spectrum of sunspots.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.4
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• pp.331-334
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• 2009

In this paper, we present a surface relaxation model in atomistic calculations for thin nanofilms. This surface relaxation model is very simple model which have only two degrees of freedoms to determine the atomic positions of nanofilms. Whereas in conventional molecular statics simulations, the same number of degrees of freedoms at all atom positions are used as unknown variables. In order to prove the reliability of the presented model, we present the results of self-equilibrium strain calculations with the surface parameters obtained from this model.