• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1271-1272
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• 2015

송전선로 아래에서의 전기장과 자기장의 계산은 2013년 밀양 송전탑 사건에서 볼 수 있듯이 매우 중요한 문제로 대두되고 있다. 공간을 전파해 나가는 전자파의 특성과는 다르게 5~60Hz의 매우 낮은 주파수(ELF: Extremely Low Frequency)로 송전을 하는 송전선로에서는 발생원으로부터 거리에 따라 반비례하여 그 크기가 작아지는 정전기장 및 정자기장을 발생시킨다. 하지만 수백 kV의 높은 송전전압 때문에 주변에서의 전기장 자기장의 값이 매우 크게 되고 이로 인한 논란이 많기 때문에 정확한 정량적 해석이 불가피한 실정이다. 본 논문에서는 수백 kV로 송전되는 송전선로에서 발생 하는 전기장과 자기장을 해석적으로 계산하고 지면으로 부터 특정한 높이에 따라 전기장 자기장이 어떻게 변화 하는지에 대한 결과를 분석 하였다. 송전 선하에 전기장 및 자기장의 분포는 MATLAB을 통해서 계산 되었다.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.678-680
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• 2001

본 연구는 탐지대상물체의 형상인식이 가능한 비접촉, 원격 탐지장치의 개발에 관한 것이다. 본 연구에서는 2극 또는 4극의 정자기장을 인가할 때 탐지 대상 물체에 의한 자기장의 자계외곡을 32개의 Hall Sensor로 감지하여 탐지 대상 물체를 인식하는 원격 감지 System을 설계하였다. 투자율에 따른 민감도는 10 이하에서 우수한 특성을 보였고 위치에 따른 민감도는 2극에서는 어느곳에 있어도 특성이 좋았고 4극에서는 중심에서는 특성이 좋지 않으나 물체가 센서 가까이에 있을 때 특성이 좋았다.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.52-53
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• 2002

스핀밸브 구조는 현재 고기록밀도 자기저장 분야에서 그 응용범위가 넓다. 이런 고기록밀도를 달성하기 위해서는 자기저항곡선의 비대칭성 문제가 중요하다. 그러므로 비대칭성 문제를 해결하여 센서의 민감도를 높이기 위해서는 고정층에서 나오는 정자기장을 제어하는 것이 필요하다. 이런 문제를 해결하기 위해 IBM에서 최초로 합성형 스핀밸브 구조가 도입하였다 [1]. 이런 합성형 스핀밸브는 기존의 스핀밸브에 비해 열적으로나 또는 자기적으로 매우 안정한 장점을 가지고 있다. (중략)

• Journal of the Korean Magnetics Society
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• v.9 no.2
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• pp.85-90
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• 1999

The ferromagnetic resonance study of the magnetostatic wave modes for an YIG thin film, grown by a liquid phase epitaxy method, was performed by an FMR spectrometer at room temperature. The magnetostatic surface wave and backward volume wave modes show periodic excitations in parallel configuration, whereas the complex spectra were observed in perpendicular configuration. The resonance spectra in parallel configuration can be well explained by the Walker and Damon-Eshbach theory. The peak-peak line width of uniform mode was 0.4 Oe. The saturation magnetization $M_s$ of the YIG thin film was calculated as 137 emu/㎤. In order to know the dependence of the magnetostatic modes as a function of the saturation magnetization and the thickness, the (1,1) and (3,1) modes of the magnetostatic backward volume wave were compared and theoretically calculated.

• Journal of the Korean Magnetics Society
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• v.21 no.6
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• pp.219-224
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• 2011

The motion features of sanals inside of the primo vascular system (PVS), that is so-called the Kyungrak system, are investigated under a low static magnetic field by using the anatomy technology and optical microscope. The sanals with a size of about 1 selected and separated from the primo vessel and node of the real PVS inside of the surface of the internal organs are observed from rabbits' abdominal wall and dipped with PBS liquid inside of petri dish. The sanal's moving velocity along the direction of magnetic field (xdirection) and perpendicular to the direction of magnetic field (y-direction) under the low magnetic field of 0 Oe, 20 Oe, 40 Oe, 60 Oe, and 80 Oe, respectively, is observed below a internal temperature of $38^{\circ}C$. Ten sanals' moving velocities versus magnetic field are shown two differently dominant tendencies with an average velocity of 0.9 pixel/s and a random velocity according to the x-direction and y-direction, respectively. This experimental results imply that the rotating motion of sanal with nuclei DNA composed of many inorganic magnetic materials of Mn and Co is monotonically weakened by the increase of applied magnetic field.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.62-65
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• 2003

본 연구는 탐지대상물체의 형상인식이 가능한 비접촉, 원격 탐지장치의 개발에 관한 것이다. 본 연구에서는 2극 또는 4극의 정자기장을 인가할 때 탐지대상 물체에 의한 자기장의 자계 왜곡을 홀 센서로 감지하여 탐지 대상 물체를 인식하는 원격 감지 시스템을 설계하고 제작하여 특성을 분석한 결과 2극과 4극 시스템 모두 비 투자율의 변화를 감지 할 수 있었고, 특히 탐사물체의 위치 파악에는 2극 시스템이 4극 시스템에 비하여 좋은 특성을 보였다.

• Journal of the Korean Magnetics Society
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• v.10 no.1
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• pp.22-29
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• 2000

The effective linewidth was measured using the conventional cavity perturbation method at 9.43 GHz in room temperature for Ca-Zr substituted yttrium iron garnet plate. The experimental set-up consists of the network analyzer, the electromagnet and the cylimdrical TE001 cavity. Measurement was performed in the static magnetic field perpendicular to the sample plane. The real and imaginary parts of diagonal component of the microwave susceptibility tensor are obtained from the resonance frequency and the quality factor Q of the cavity. Variations of the effective linewidth was qualitatively explained with the spin wave scattering theory.

• The Journal of Korean Institute for Practical Engineering Education
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• v.2 no.2
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• pp.55-60
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• 2010

We usually encounter Electro-magnetics phenomenons and only feel some part of that, but it is hard to feel it visually. Moreover understanding physically and quantitatively is not a easy work. These electrostatic field theory, magnetostatic field theory and interchange magnetic field theory combined with electromagnetic field are formulated experimentally and theoretically by James Clerk Maxwell in 1873. Electromagnetic field takes electro-magnetic phenomenons as a expansion of formula originated in Maxwell equations. Since this is based on expansion of formula, it is hard to understand for many students not only middle school and high school students learning it at the first time but also college students studying physics as a elementary class and even majors in electromagnetic field. The program is developed as a visual aid to cope with these problems, and even to deal with complex problem to estimate solution using numerical method.

• Journal of Biomedical Engineering Research
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• v.36 no.1
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• pp.31-36
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• 2015

In this study, we evaluated the effects of static magnetic fields of earphones and headphones on pacemakers and implantable cardioverter defibrillators(ICDs). Five pacemakers and three ICDs were subjected to in-vitro test with three headphones which were an in-ear earphone, clip-on headphone, and closed-back headphone. Each implantable device was placed in close proximity(within 3 mm) to the ear-pad of each of the earphone and headphones for 3 min. As a result, no effects were observed on the pacemakers for the earphone and headphones during the test, but an effect was observed on one ICD for the clip-on and closed-back headphone during the test. When the ICD was placed in close proximity to the headphones, the ICD temporarily suspended functions of tachyarrhythmia detection and therapy. The effect was not observed in this study when the headphones were at least 2 cm from the ICD. Based on these findings, patients with ICDs should be advised to keep earphones and headphones at least 2 cm apart from their ICDs.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.1
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• pp.46-53
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• 2000

Magnetostrictive sensors which can be used effectively to detect flaws in pipe were fabricated. The optimal conditions to obtain the maximum generation efficiency of the ultrasonic wave were established. In case of the used steel pipe the optimal magnetic field was $250{\sim}350Oe$ and the coil width of 15mm showed the best efficiency for generating a wave with the frequency of 180 kHz. In the best condition, the wave can propagate further than 50m without serious attenuation. The amplitude of the ultrasonic wave reflected from artificial flaw had a good linear relationship to the cross-sectional area of the flaw.