• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.172-176
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• 1997

It is likely that the corona discharge appears due to the motion and the multiplication of electron and ion under the nonuniform electric field. Because the motion and the multiplication of electron and ion are the function of electric field, for the simulation of the corona discharge, we have to calculate the electric field, before the calculation of the motion and the multiplication of electron and ion. In this paper, the electric field is calculated on the assumption that the gap between a hyperboloidal needle and a plane is 1-dimension, and the motion and the multiplication of electron and ion are determined by Flux-Corrected Transport method. For this purpose, we solve the electron and ion continuity equation together with Poisson equation. We calculated the current density and the electron and ion density distributions between electrodes as well as electric field distortion due to the space charge assuming that the discharge channel radius is 100${\mu}{\textrm}{m}$. In this simulation, it is found that the current density has one peak as observed by experiment, and electric field distortion is important to the formation and the stability of the corona discharge.

• Journal of the Korean earth science society
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• v.28 no.7
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• pp.936-946
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• 2007

Analytical geopotential field in balance with the sectoral mode (the first symmetric mode with respect to the equator) of the Rossby-Haurwitz wave on the inclined rotation axis was derived in presence of superrotation background flow. The balanced field was obtained by inverting the divergence equation with the time derivative being zero. The inversion consists of two steps, i.e., the evaluation of nonlinear forcing terms and the finding of analytical solutions based on the Poisson's equation. In the second step, the forcing terms in the from of Legendre function were readily inverted due to the fact that Legendre function is the eigenfunction of the spherical Laplacian operator, while other terms were solved either by introducing a trial function or by integrating the Legendre equation. The balanced field was found to be expressed with six zonal wavenumber components, and shown to be of asymmetric structure about the equator. In association with asymmetricity, the advantageous point of the balanced field as a validation method for the numerical model was addressed. In special cases where the strength of the background flow is a half of or exactly the same as the rotation rate of the Earth it was revealed that one of the zonal wavenumber components vanishes. The analytical balanced field was compared with the geopotential field which was obtained using a spherical harmonics spectral model. It was found that the normalized difference lied in the order of machine rounding, indicating the reliability of the analytical results. The stability of the sectoral mode of Rossby-Haurwitz wave and the associated balanced field was discussed, comparing with the flrst antisymmetric mode.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.4
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• pp.201-208
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• 2002

In this paper, we present a new formulation using time-domain electric field integral equation (TD-EFIE) to obtain transient scattering response from arbitrarily shaped three-dimensional conducting bodies. The time derivative of the magnetic vector potential is approximated with a central finite difference and the scalar potential is time averaged by dividing it into two terms. This approach with an implicit method using central difference results in accurate and more stable transient scattering responses from conducting objects. Detailed mathematical steps are included and several numerical results are presented and compared with the inverse discrete Fourier transform (IDFT) of the frequency-domain solution.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.2
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• pp.31-37
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• 2008

In this paper, we analyzed the dynamic behavior of magnetic fluid in a circular pipe with multiple permanent magnets. Magnetic fluid react on magnetic field against the normal fluid. In other words, magnetic fluid flow has the electromagnetism and fluid mechanics. So magnetic fluids has studied about the fluids properties and experiment. In this paper we studied the magnetic fluids velocity and pressure distribution for the novel type actuator. Because the velocity and pressure distribution is the important element of the magnetic fluids flow. First, we analyzed the Maxwell equation for the multiple permanent magnet and then concluded the governing equations for the magnetic fluid flow using the equation of Navier-Stokes. And, we simulated the dynamic behavior of magnetic fluid flow using the FEM(Finite Element Method). And we illustrated the relation between magnetic field and dynamic behavior of magnetic fluid flow.

• Bulletin of the Korean Mathematical Society
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• v.42 no.3
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• pp.485-489
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• 2005

We show that any Drinfeld module of rank 2 on IF'q[T] over a global function field K has a global minimal Drinfeld module equation if and only if h(O$_{K}$) = 1.

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.215-216
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• 2008

Electricity unified field is described based on magnetic theory. Maxwell Einstein Lorentz Equation & pair particle photon model was introduced for Photonics. Refractive index is calculated as deceleration and deflection of photon due to photo-induced surface magnetism. MEL equation was proved with magneto-jet assumption.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.475-480
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• 2001

In this study, a empirical equation which can be feasibly used to evaluate minimal track buckling strength without exact numerical analysis is presented. Parameter studies we carried out to investigate the effects of the individual factor on buckling strength. In order to simulate track buckling in the field as precisely as possible, a rigorous buckling model which accounts for all the important parameters is adopted. A empirical equation for prediction of minimal track buckling strength is derived by taking nonlinear regression of data which are obtained from numerical analyses. Its characteristics and applicability are investigated by comparing the results by the presented equation with the one by the equation which was presented in japan, and is frequently using in korea when designing track structure.

• Journal of information and communication convergence engineering
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• v.7 no.1
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• pp.57-61
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• 2009

This paper has presented the subthreshold current model of FinFET using the potential variation in the doped channel based on the analytical solution of three dimensional Poisson's equation. The model has been verified by the comparison with the data from 3D numerical device simulator. The variation of subthreshold current with front and back gate bias has been studied. The variation of subthreshold swing and threshold voltage with front and back gate bias has been investigated.

• Journal of Korean Society of Transportation
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• v.10 no.1
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• pp.21-40
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• 1992

We examine primarily the existing study procedures for freeway weaving section by comparing speed estimates. Most methods have poor predictions because of neglecting the weaving vehicle influ-ence. In this study we develop the speed prediction equation considering the weaving influence area i.e, weaving box. Assuming that speeds outside weaving box are similar to speeds in freeway basic sec-tions we develop speed equation in box based on the field data. Moreover level of service criteria and weaving analysis precedure are proposed under the new speed prediction equation.

• Proceedings of the KIEE Conference
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• 1985.07a
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• pp.344-347
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• 1985

Hew dual integral equation for electromagnetic field scattered by an arbitrary dielectric wedge is formulated. In order to check the validity and physical meaning of the formulated equation, it is applied to the well-known case which is the diffraction by a perfectly conducting wedge.