• Proceedings of the KSEG Conference
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• 2001.03a
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• pp.83-90
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• 2001

• Explosives and Blasting
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• v.21 no.4
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• pp.23-35
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• 2003

This study is to clarify the comparative relationship and a mechanical anisotropy of rock on the subject of granite distributed in the Namwon area Uniaxial compressive and Brazilian strengths with respect to the horizontal and vertical axes of granite are shown the linear relation. In the case of the result of the p-wave velocity measurement. it is represented that the velocity of vortical direction is faster about 10 to 15% than other two horizontal directions. The difference between velocities is caused by a developmental pattern of microcracks distributed in rock. Moreover, this result is very consistent with the result investigated through thin sections. The proportion of uniaxial compression strength to Index of point load strength ($Is_{(50)}$) is 18~20 times in case of granite. Uniaxial compressive strength is relatively good relationship with point load strength, Schmidt hammer rebound value, and tensile strength point load strength of them is the best comparative relationship. It is indicated that point load test is the most useful tool to estimate uniaxial compressive strength, comparing with other experimental methods.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.9
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• pp.29-39
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• 2001

Dielectric cover effect of rectangular microstrip patch antenna on uniaxial substrates with airgap are studied. First, we derive Dyadic Green function for selected anisotropic material by constitutive relation and then formulate integral equations of electric fields using Fourier transform in space region. Using Galerkin's moment method, we discretize the electric field integral equations into the matrix form and select sinusoidal functions as basis functions. We verify the validity of numerical results and compare the results with existing ones in showing a good agreement between them. When the dielectric cover thickness is varied, the resonant frequencies and input impedances in the variation of air gap, patch length and thickness and permittivity of superstrate are presented and analyzed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.3
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• pp.293-308
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• 1999

이 논문에서는 패널, 깊은 보 그리고 전단벽과 같이 평면응력상태하에 있는 철근콘크리트 구조물의 비선형 유한요소해석에 있어서의 직교이방성 콘크리트 구성 모델의 적용성을 보여준다. 등가의 일축 변형을 개념을 토대로 콘크리트의 구성 관계가 주변형률 축과 일치하고 하중이력에 따라 회전하는 직교하는 축에 대해 제시된다. 제안된 모델은 이축 압축응력상태와 인장-압축 응력상태에서 각각 압축강도의 증가와 인장 저항력의 감소효과를 보여주는 이축 파괴영역의 정의를 포함한다. 인장균열이 발생한 후, 콘크리트의 압축강도의 감소효과가 제시되고, 인장강화효과로 알려진 철근에 의해 지지되는 콘크리트의 인장응력이 고려된다. 평균응력과 평균변형률 개념을 사용하여 힘의 평형, 적합조건 그리고 철근과 철근을 둘러싼 콘크리트 사이의 부착응력-슬림 관계를 토대로 인장강화효과를 모사하기 위한 모델이 제안된다. 유한요소 모델에 의한 예측은 유용한 실험자료와의 비교에 의해 입증된다. 이 논문에서는 해석결과와 이상화한 전단 패널실험으로부터 얻어진 실험값의 비교연구가 수행되고, 제안된 모델의 타당성을 보여주기 위해 서로 다른 응력상태하의 전단 패널 보와 벽체의 힘-변위 관계를 평가하였다.

• Journal of the Korean Magnetics Society
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• v.18 no.1
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• pp.28-31
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• 2008

We studied the effect of easy magnetization axis orientation with respect to the strip direction by measuring the magnetoresistance(MR), the magneto-optic Kerr effect(MOKE), and real-time domain evolution. The five strips were patterned on a single chip with the easy axis orientation of each strip relative to the longitudinal direction by around $0^{\circ}$, $18^{\circ}$, $36^{\circ}$, $54^{\circ}$ and $72^{\circ}$, respectively. The overall shape of field dependent MR was mostly governed by the anisotropy magnetoresistnace. The relative change of the longitudinal MR was significantly increased with increasing angle between the easy axis and strip direction, whereas, the transverse MR variation rate was decreased with increasing angle. Several MR steps were observed during the magnetization reversal, and the simultaneous measurement of the MOKE and the domain images identified that the MR steps were associated with evolution of the oppositely directed magnetic domain.

• Proceedings of the Korean Magnestics Society Conference
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• 1993.11a
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• pp.24-25
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• 1993

• Proceedings of the Korean Magnestics Society Conference
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• 1999.04a
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• pp.130-131
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• 1999

• Journal of the Korean Magnetics Society
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• v.1 no.2
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• pp.42-48
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• 1991

The basic soft magnetic characteristics of a typical Fe based amorphous $Fe_{80}B_{15}Si_{5}$ alloy were measured with pulse metheod. Quantitative relations between magnetostriction, anisotropy energy, reluctivity were investigated. The relative contribution factor of magnetostrictive and uniaxial anisotropy energy to the reluctivity were calculated. The internal stress and induced anisotropy were estimated. A tension applied to the long axis of the sample greatly enhanced induced anisotropy.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.133-141
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• 2002

Isotropic rock and anisotropic rock have different tensile strength which has the greatest influence on rock failure. In this study, elastic modulus of anisotropic rock is obtained through uniaxial compression test, and tensile strength and tension failure behavior are analyzed through indirect tensile strength test. Stress concentration factor of a specimen at the center is obtained from anisotropic elastic modulus and strain by indirect tensile strength test. Theoretical solutions for tensile strength of isotropic and anisotropic rock are compared. Stress concentration factor of anisotropic rock is either higher or lower than isotropic rock depending on the inclination angle of bedding plane. The use of stress concentration factor of isotropic rock resulted in overestimation or underestimation of tensile strength.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.12A
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• pp.1759-1765
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• 2000

공기 갭을 갖는 일축성 기판위에 마이크로 패치 안테나의 공진 주파수가 full-wave approach와 모멘트 계산법을 이용하여 연구되었다. 일축성 매질내의 구성관계식을 통하여 제안된 구조에서의 파수영역 다이애딕 그린 함수를 유도하였으며 이 결과로부터 전계 적분 방정식을 수식화하였다. 갤러킨 모멘트법을 사용하여 전계 적분 방정식을 이산화 하였으며 기저함수의 선택은 수치 해석적 수렴을 고려하여 패치 위의 실제 전류밀도와 가장 유사한 형태인 정현적 기저함수를 선택하였다. 전사모의 실험 결과의 타당성을 검증하기 위해서 기존의 결과와 비교하여 일치된 결과를 얻었다. 공기 갭의 두께와 패치 길이, 이방성 비의 변화에 따른 공진 주파수가 제시되고 분석되었다.