• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1561-1563
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• 2008

We report an optical second harmonic generation measurement that allows direct probing of dynamical carrier motion in organic field effect transistors. Carrier injection and transport process are discriminated. The mobility and contact resistance of pentacene FETs are determined from the visualized diffusion-like carrier motion.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1132-1134
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• 2005

This paper presents a design strategy of Slotless type BLDC motor using the space harmonic field method. The distribution of Back emf and torque are considered by movement of the Permanent Magnet and armature current. The result of magnetic field distribution, back-emf, and torque are in agreement with FEM.

• 한국광학회지
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• 제12권3호
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• pp.230-234
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• 2001

반전대칭이 없는 광굴절결정에 있어 위상접합이 만족되지 않은 상태에서 발생된 제2고조파의 세기가 외부전기장에 의존한다는 사실을 이용하여 광굴적결정의 광굴절율 변형현상에 관한 중요상수를 측정할 수 있는 방법을 개발하였다. 마커무늬의 전기장의존도에 관한 근사식을 구하였고 이를 이용하여 제2고조파의 세기변화로부터 공간전하장의 크기를 측정할 수있었다. 실험적으로 congruent $LiNbO_3$에 빛을 두가지 다른 세기로 비추어 유도되는 공간저하장의 시간의존성을 조사하였고 측정결과를 근사식과 비교분석하여 $LiNbO_3$의 광기전력상수, 암전도상수 및 광전도상수를 결정할 수 있었다.

• 한국자기학회지
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• 제7권3호
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• pp.159-165
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• 1997

최근에 자계시스템을 해석함에 있어서 서로 다른 위상을 갖는 자속밀도와 자계의 세기간의 벡터적인 관계를 고려하는 것이중요시 되고 있으며 그 방법에 관한 연구도 많이 이루어지고 있다. 본 연구에서는 유한요소법과 이차원 투자율 텐서를 이용하여 자속밀도와 자계의 세기를 계산하였다. 특히 이 방법으로 회전이력현상을 정확하게 고려하여 회전자속밀도와 회전 자계의 세기를 계산할 수 있음을 보였으며 또한 기본파 성분만을 가진 자속 뿐만 아니라 고조파를 포함하고 있는 자속의 계산을 위한 방법을 제시하고 게산결과와 실험결과의 비교를 통해서 제안된 방법의 타당성을 제시한다.

• 대한수학회논문집
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• 제35권3호
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• pp.1019-1035
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• 2020

In this paper, we introduce the deformed-Sasaki metric on the tangent bundle TM over an m-dimensional Riemannian manifold (M, g), as a new natural metric on TM. We establish a necessary and sufficient conditions under which a vector field is harmonic with respect to the deformed-Sasaki Metric. We also construct some examples of harmonic vector fields.

• 대한수학회지
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• 제49권5호
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• pp.977-991
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• 2012

Let (M,F) and (M',F') be two foliated Riemannian manifolds with M compact. If the transversal Ricci curvature of F is nonnegative and the transversal sectional curvature of F' is nonpositive, then any transversally harmonic map ${\phi}:(M,F){\rightarrow}(M^{\prime},F^{\prime})$ is transversally totally geodesic. In addition, if the transversal Ricci curvature is positive at some point, then ${\phi}$ is transversally constant.

• Journal of Mechanical Science and Technology
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• 제18권10호
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• pp.1747-1754
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• 2004

In this study, a new harmonic axisymmetric thick shell element for static and dynamic analyses is proposed. The newly proposed element considering shear strain is based on a modified Hellinger-Reissner variational principle, and introduces additional nodeless degrees for displacement field interpolation in order to enhance numerical performance. The stress parameters selected via the field-consistency concept. are very important in formulating a trouble-free hybrid-mixed elements. For computational efficiency, the stress parameters are eliminated by the stationary condition and then the nodeless degrees are condensed out by the dynamic reduction. Several numerical examples confirm that the present element shows improved efficiency and yields very accurate results for static and vibration analyses.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권2호
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• pp.76-82
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• 2006

This paper investigates the magnetic field behavior and its iron losses in the stator core using electrical steels. The analysis model is a brushless motor with the permanent magnet. The elliptical rotating and alternating flux distributions with non-sinusoidal waveform are obtained by Finite Element Method and then their harmonic components are extracted. Based on these results, the local iron losses in the stator core caused by the harmonic flux are calculated. And then this paper explains the relation between flux waveform and iron loss produced in each part of the stator core. Furthermore, the iron loss at no load condition is measured and compared with the analysis results.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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• pp.237-240
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• 2007

The evaluation of shear modulus (or shear wave velocity) profile of site is very important in the various fields of geotechnical engineering. To obtain shear wave velocity profile, various in-situ seismic methods using surface waves have been developed. These surface wave based in-situ seismic methods have their own strength and weakness. In this study, new seismic site characterization method using the harmonic wavelet analysis of wave (HWAW) was proposed to overcome some of weaknesses in the existing surface wave based seismic site characterization methods. HWAW method which is based on time-frequency analysis using harmonic wavelet transform have been developed to determine phase and group velocities of waves. In order to estimate the applicability of HWAW method, field tests were performed. Through field applications and comparison with other test results, the applicability of the proposed method were verified.

• 대한수학회논문집
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• 제36권1호
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• pp.135-147
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• 2021

In this paper, we introduce the harmonicity of a covector field on a Riemannian manifold (M, g) to its cotangent bundle T∗ M equipped with g-natural metric. Afterward we also construct some examples of harmonic covector fields.