• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1448-1450
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• 1994

The breakdown voltages of punchthrough-mode diodes with cylindrical junction are analytically calculated, The proposed method, which is based on th Gauss's law, estimates the lateral expansion of the depletion region as well as the electric field and the charge distribution. The proposed method is given in terms of epitaxial layer width, the epitaxial layer doping concentration, and curvature radius of the junction edge. The calculation results agree well with the MEDICI simulation results for various device parameters.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권4호
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• pp.182-186
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• 1999

Evaluation of the AC losses in the HTS tapes which are used in electric power machines in one of the important topics in this field. This paper deals with the calculation and measurement of the magnetization loss in HTS tapes. Bean model is adopted for the theoretical calculation of the magnetization loss. Magnetization method is used for the measurement of the loss. Two types of the HTS tape model, multi-filamentary model and mono-filamentary model, are used to evaluate the magnetization loss in this paper. According to the results of the analysis, large discrepancy between the calculated and measured value is observed in multi-filamentary model is more useful than multi-filamentary model for the evaluation of the magnetization loss.

• 대한전기학회논문지:전력기술부문A
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• 제53권8호
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• pp.438-445
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• 2004

This paper presents a new numerical spectral domain algorithm devoted to blocking unsuccessful automatic reclosing onto permanent faults and fault distance calculation. Arc voltage amplitude and fault distance are calculated from the fundamental and third harmonics of the terminal voltages and currents phasors. From the calculated arc voltage amplitude it can be concluded if the fault is transient arcing fault or permanent arcless fault. If the fault is permanent automatic reclosure should be blocked. The algorithm can be applied for adaptive autoreclosure, distance protection, and fault location. The results of algorithm testing through computer simulation and real field record are given.

• 한국전자파학회논문지
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• 제29권9호
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• pp.701-706
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• 2018

본 논문에서는 임의의 대형구조의 전자기 특성을 효율적으로 해석하기 위해 대표적인 전자기 수치해석 기법의 하나인 모멘트법 기반 직접풀이법 중 CBFM의 원거리 상호작용 계산의 가속화 알고리즘을 제안하였다. 대형구조의 전자기 특성해석을 위해서는 계산시간의 단축이 필수적이며, CBFM 해석법에서 원거리 블록 간의 상호작용을 다중극전개방법을 사용한 근사화를 통해 복잡도를 크게 감소시킨 수식을 도출하였다. 본 논문에서 제안된 새로운 알고리즘을 도체구와 전투기의 레이다 단면적 계산에 적용하여 기존의 CBFM과 비교하여 정확도 손실 없이 계산시간이 각각 34 %, 74 % 단축되어 대형구조 문제해석에 효율적이라는 것을 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 추계학술대회 논문집
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• pp.33-35
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• 1988

From the study of mechanism of electrical conduction of film which is made from Polyethylene Terephthalate at very high temperature which is larger than low electric field and glass transition point, we find that there is a extraordinary non ohmic region (I∝V$^n$, 0

• Journal of Magnetics
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• 제16권1호
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• pp.6-9
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• 2011

Spin-motive force has drawn attention because it contains a fundamental physical property. Spin-motive force creates effective electric and magnetic fields in moving magnetization; a vortex is a plausible system for observing the spin-motive force because of the abrupt profile of magnetization. However, the time-averaged value of a spin-motive force becomes zero when a vortex core undergoes gyroscopic motion. By means of micromagnetic simulation, we demonstrates that a non-zero time-averaged electric field induced by spin-motive force under certain conditions. We propose an experimental method of detecting spin-motive force that provides a better understanding of spin transport in ferromagnetic system.

• 한국전자파학회논문지
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• 제7권2호
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• pp.105-116
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• 1996

급전선과 직교된 전자기결합 마이크로스트립 다이폴안테나는 주로 주파수 영역의 적분방정식 및 모멘트법에 의해, 다이폴의 전류분포를 구하므로써 설계 및 해석이 이루어졌으나, 본 연구에서는 FDTD 방법을 이용하여 각 다이폴의 전류분포를 직접 계산하여, 전자기결합 다이폴 배열안테나의 설계 및 해석 가능성을 제시하였다. 이 경우, 맥스웰방정식 적분형을 유한차분형태로 표현한 수식을 적용하였으며, 계산된 각 다이폴의 전류분포에 의해 복사전계를 구하므로써, 표면전류 및 자류밀도를 계산하여 복사패턴을 구하는 방법에 비해 계산과정과 시간이 크게 단축됨을 보였다.

• 한국전기전자재료학회논문지
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• 제25권3호
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• pp.218-223
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• 2012

A rigorous electro-optical simulation and ray tracing for an electric field driven liquid crystal Fresnel lens was proposed to obtain design parameters of the electrode pattern of the Fresnel lens. The optimal design was carried out using Taguchi's experimental method for 17.1"($368{\times}229.5$ mm) wide LCD panels with 9 views. For the calculation of the distribution of liquid crystal molecules and the optical transmission of the panel, finite difference method and extended Jones matrix method were used to deal effectively with highly nonlinear and complicated motional equations of the liquid crystal molecules and to obtain the oblique transmission characteristics of the LCD panel. As simulation results, the optimal lengths of the 3 electrodes of the Fresnel lens are 4.0 ${\mu}m$, 30 ${\mu}m$ and 83 ${\mu}m$, respectively, and the locations of the second and third electrodes are 32.9-33.0 ${\mu}m$ and 45.9-46.0 ${\mu}m$, respectively. The optimal applied voltage of the 3 electrodes are found to be 5.75 V, 7.80 V and 11.9 V, respectively.

• 대한기계학회논문집B
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• 제29권1호
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• pp.87-94
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• 2005

A computer code for Electrical Capacitance Tomography (ECT) is developed to sense the cross sectional phase distribution of two-phase flow in the rectangular pipe in which the tomography sensor furnished by the insulated wall, electrodes, and electric field screen. The computer code had two steps for the image reconstruction. In the forward projection step, the sensitivity matrix was constructed based on the electric field calculated by the finite difference method. In the backward projection step, the sensitivity matrix and the measured capacitances were used to reconstruct the cross sectional image. Several algorithms including LBP, TR, ITR, and PLI were employed to find the proper one for the two-phase flow analysis. Since the dielectric constant of the water in two-phase flow is sensitive to the thermal parameter such as, temperature and pressure, the developed code was evaluated to find their accuracy, speed of calculation, and sensitivity to the variation of the dielectric constant. It was found that the iterative methods are superior to the direct methods for the image reconstruction, and the PLI method was the best in the variation of the dielectric constants.

• KIEE International Transactions on Electrophysics and Applications
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• 제11C권4호
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• pp.107-112
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• 2001

Laser Thomson scattering measurements of electrom temperature and density in a neutral loop discharge (NLD) plasma were performed in order to reveal the electron behavior around the neutral loop (NL). The experimental results were examined by using a simulation model that included effects of a three dimensional electromagnetic field with spatial decay of the RF electric field, and the limitation of the spatial extent of the electron motion and collision effect. From the experiments and modeling of the electron behavior, it was found that NLD plasma posses the electron temeprature $T_{e}$ and density ne peaks around the NL is essential for the formation of plasma. Also, the optimum condition of plasma production could be simply estimated by the calculation of $U_{av}$ and $F_{0}$././.