• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1243-1245
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• 2005

신뢰성 있는 초전도전력 케이블의 설계를 위하여 초전도 케이블 각층의 인덕턴스 산정방법을 기존 방법과 새로 제안된 방법을 비교하였으며, 새로 제안된 방법에 의한 인덕턴스 계산을 검증하기 위하여 상용전자장해석 프로그램을 이용하여 그 계산결과를 비교하였다. 기존의 초전도 전력케이블의 인덕턴스 산정방식인 Go and Return Method 및 Energy Method에 대한 전자기적 타당성을 재검토하였으며, 더 나아가 Newman Method와 Geometric Mean Distance를 결합한 Neumann-GMD Method를 제안하였다. 각 방법의 신뢰성 검증을 위하여 상업적으로 검증된 전자장 해석 tool인 OPERA를 이용하여 특정 피치에 대한 2층 구조의 케이블을 모델링하고 그 인덕턴스를 계산하여, 각 방법에 의하여 계산된 인덕턴스 값과 비교하였다. 이 과정을 통하여 가장 신뢰성 있는 인덕턴스 계산법을 선택하여 초전도 전력 케이블의 설계에 적용하고자 한다.

• Journal of the Korean Chemical Society
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• v.47 no.2
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• pp.109-114
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• 2003

The electronic absorption spectra of trans-$[CrX_2([15]aneN_4)]ClO_4\;([15]aneN_4$=1,4,8,12-tetraazacyclopentadecane; X=F, Cl) complexes have been interpreted using the ligand field theory. An AOMX program is used to optimize the differences between the calculated and the observed positions for the spin-allowed transition bands. The crystal field theory(CFT) parameter is directly related to the angular overlap model(AOM), normalized spherical harmonic hamiltonians(NSH), and semiempirical parameters. The various ligand field parameters are discussed in terms of their chemical significances. According to the ligand field analysis, we can confirm that the fluoride ligand is a very strong ${\sigma}-$ and ${\pi}-$donor while the chloride has weak ${\sigma}-$ and ${\pi}-$donor properties toward chromium(III) ion.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.9
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• pp.873-882
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• 2013

The effective way of estimation and analysis of EMI(Electromagnetic Interference) in Wireless Power Transfer System operating at 13.56 MHz is proposed. In this paper methodology of driving magnetic field strength and electric loop current of two antennas which are in free space and on PEC plane using image theory and duality is proposed. Perfect electric conductor(PEC) is planar, infinite in extent, and perfectly conducting plane. And we will refer it as PEC plane. A equivalent circuit model is used to analyze. Using this theoretical analysis, we can derive maximum magnetic field strength of the far-field region numerically using measured data of near-field maximum magnetic field strength. The experimental results using commercial numerical simulation tool are in agreement with the theoretical results. Also, using the derivation of maximum magnetic field strength in the far-field region, we can easily estimate the maximum allowable power dissipation that meets EMI regulations.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.103-105
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• 2002

전기-기계 결합시스템에서의 동특성을 정확히 해석하기 위해서는 해석모델의 전기회로 방정식과 운동방정식이 함께 고려되어야 한다. 이때 시스템의 다양한 입력과 기하학적인 구조 등에 대한 등가회로 상수는 시스템의 전반적인 특성에 매우 민감하게 작용하므로 중요하게 고려 되어야한다. 본 논문에서는 전자기시스템의 회로상수를 미리 계산한 다음 이를 기계 역학시스템에 적용하여 다양한 전기적 입력과 외부 부하특성에 대하여 어떻게 동작하는지를 알아보았다. 전자기시스템의 회로상수 추출을 위해 전자장해석은 유한요소법을 이용하였으며 전기회로 방정식과 운동방정식이 함께 고려된 상태 미분방정식은 4차 Runge-Kutta 미분방정식 해법을 이용하여 운동특성을 해석하였다. 계산된 결과는 수학적으로 검증된 미분방정식과 비교하여 검증하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2381-2387
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• 2013

This paper deals with an optimal angle error reduction method of magnetic hall sensor using hall effect elements with yoke. The magnetic position sensor is required to generate ideal sine and cosine waveforms from its hall effect elements according to rotation angle for precise angle information. However, the output signals are easy to include harmonics due to uneven magnetic field distribution from disturbance in the vicinity of hall effect elements. Thus, The paper studies a way which makes sine and cosine waveforms robust in disturbance and reduces harmonics by installing a yoke around Hall effect elements. The angle detection simulation for the magnetic hall sensor is performed by 3 dimensional finite element method and Taguchi method, one of the design of experiments. For the Taguchi method, three design parameters related to position of hall effect elements and shape of hall effect element yoke are selected.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.9
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• pp.7-14
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• 2000

This paper examines the constraints imposed in the usage of the conventional two-mode coupling model in the context of a cascaded long-period fiber grating and presents a set of approximate conditions that must be satisfied for the model to be applicable in the analysis of such a structure. Numerical examples based on the guidelines are provided for a set of realistic grating parameters and their practical implications on the allowed grating period variations for a given bandwidth are discussed.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.161-162
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• 2014

본 연구의 목적은 HVDC Valve module 및 valve tower에 유입되는 냉각 유체의 유동장 동적 해석과 동시에 냉각 유체의 동적 특성을 측정 비교함으로써 유동 해석의 적합성을 판단하고, HVDC valve module과 valve tower의 냉각 유로 및 관련 기구 설계의 기초 자료로 활용하는데 그 목적이 있다.

• Progress in Medical Physics
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• v.14 no.1
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• pp.1-7
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• 2003

In this work we developed a EGS4 control code to calculate the dose distributions for high energy electron beams in water phantom applied longitudinal magnetic field. We reviewed the electron's motion in magnetic field and delivered equations for direction changs of the electron by the external magnetic field. The mathematical results are inserted into the EGS4 code system to account for the presence of external magnetic fields in phantom. The electron pencil beam paths of 6 MeV in water phantom are calculated for magnetic fields of 1-3 T and the dose distributions for a field of 1.0 cm in diameter are calculated for magnetic fields of 0.6-1 T using the code. From the results of path calculations we found that the lateral ranges of the electrons are reduced in the magnetic field of 3 T. For a field of 1 cm diameter and a magnetic field of 1 T, the small dose enhancement near the range of the electrons on the depth dose and the penumbra reduction of 0.15 cm on the beam profile are observed. We discussed and evaluated the results from the theoretical concepts.

• The Journal of the Acoustical Society of Korea
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• v.27 no.7
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• pp.325-332
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• 2008

The prediction method of TS parameters, frequency response, and electrical input impedance is proposed with physical properties of parts and results of electromagnetic FEA(Finite Element Analysis) in a loudspeaker driver design. In design for weight reduction and improvement of flux density asymmetry, the prediction results are well coincided with measurement ones. As the applications, it can be applied in design for improvement of the $2^{nd}$ harmonic distortion with flux density distribution analysis. The proposed method is expected to be utilized for reducing trial-and-error process in electromagnetic parts design. It can also be used for providing guidelines for parts selection in the early stages.

• Journal of the Korean Vacuum Society
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• v.21 no.2
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• pp.69-77
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• 2012

Visualization of the electromagnetic vector fields are presented and examined with Mathematica. Vector fields may be used to represent a great of many physical quantities in various area of physics, including electromagnetism with vector differential operators. Because they deal with abstract, three-dimensional fields that are some times very difficult to visualize, electromagnetism can be conceptually rather difficult. Visual representation of such an abstract vector fields is invaluable to student or researchers working in this field and also helps teaching electromagnetism to physics or engineering students. Mathematica provides a wider range of graphical tools including plot of vector fields and vector analysis, which can be applied to visualization of electromagnetic system. We have visualized the most fundamental concepts of the electromagnetic vector $\vec{E}=-\vec{\nabla}_{\varphi}$, $\vec{D}={\epsilon}\vec{E}$, $\vec{\nabla}{\times}\vec{A}$, $\vec{B}={\mu}\vec{H}$, $\vec{B}={\mu}_0(\vec{H}+\vec{M})$, which are confirmed with vector calculations and valid graphically with some presentations.