• 한국초전도ㆍ저온공학회논문지
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• 제11권4호
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• pp.33-36
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• 2009

An air gap between the pancake windings was provided in this paper to increase the central magnetic field of a high temperature superconducting (HTS) magnet consisting of pancake windings. Unlike the LTS magnet, providing an air gap between the pancake windings increases the central magnetic field of a HTS magnet. Furthermore, the uniformity of the magnetic field near the center of the magnet increased because the pancake windings spread out in wider area. Effects of the air gap on the central magnetic field of an HTS magnet was described in this paper, Calculation of the critical current was carried out by using E-J relation of the HTS wire and the optimization technique was adopted to obtain the appropriate critical current which could maximize the central magnetic field. Pancake windings with BSCCO-2223 HTS wire were wound on glass epoxy bobbin. 6 double pancake windings with 200 turns were used to construct a HTS magnet. Characteristics of the HTS magnet including the central magnetic field and the uniformity of the magnetic field were measured and compared with the results of calculation.

• 한국전자파학회논문지
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• 제28권1호
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• pp.61-68
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• 2017

본 논문에서는 저주파 대역에서 동작하는 무선전력전송 시스템에서 발생하는 자기장을 저감하기 위한 개선된 자기장 저감 구조를 제안하였다. 제안된 구조는 자성체와 도체로 구성되었으며, 적용된 다양한 설계 파라미터를 최적화하여 전력전송을 위한 자기장의 상쇄효과는 최소화 하면서 시스템 주변으로 누설되는 자기장 상쇄효과는 개선되도록 하였다. 무선전력전송 시스템의 효율과 주변으로 누설되는 자기장 저감 효과를 컴퓨터 시뮬레이션과 측정을 통하여 분석 및 검증을 하였다. 시뮬레이션 분석 결과, 제안된 구조가 적용된 무선전력전송 시스템의 전력전송효율은 약 77 % 수준으로 기존의 전력전송효율과 동등한 수준을 유지하였다. 또한, 고효율을 유지하는 구조들과 비교하여 최대 근접지점에서 누설되는 자기장의 세기를 약 29~37 % 저감할 수 있었다.

• Journal of Magnetics
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• 제8권1호
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• pp.74-78
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• 2003

The largest advantage of magnetic micromachine is wireless operation. This advantage makes it suitable for medical micromachine working inside the human body. In the medical field, low invasion treatment is very important From this point of view, very small machines working in the body without power supply cables meet the needs of the medical field. In this paper, we report about magnetic wireless actuators for medical applications.

• Journal of Magnetics
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• 제18권1호
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• pp.43-49
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• 2013

A pulsed ferrite magnetic field generator (FMFG) was designed for the use in the 1000 m long through-the-earth (TTE) communication system for mining disaster situations. To miniaturize the TTE system, a ferrite core having 10,000 of permeability was used for the FMFG. Attenuation of the magnetic field intensity from the FMFG (200-turn and 0.18 m diameter) was calculated to be 89.95 dB at 1000 m depth soil having 0.1 S/m of conductivity. This attenuation was lower than 151.13 dB attenuation of 1 kHz electromagnetic wave at the same conditions. Therefore, the magnetic-field was found to be desirable as a signal carrier source for TTE communications as compared to the electromagnetic wave. The designed FMFG generates the magnetic field intensity of $1{\times}10^{-10}$ Tesla at 1000 m depth. This magnetic field is detectable by compact magnetic sensors such as flux gate or magnetic tunneling junction sensor. Therefore, the miniature FMFG TTE communication system can replace the conventional electromagnetic wave carrier type TTE system and allow reliable signal transmission between rescuer and trapped miners.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.115-118
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• 2003

The sensor at liquid nitrogen temperature showed the increase of electrical resistance by applying magnetic field. Actually, the voltage drop across the sensor was changed from zero to a value more than $100\;{\mu}V$ by the applied magnetic field. The change of electrical resistance depended on magnetic field. The sensitivity of this sensor was $2.9\;{\Omega}/T$. The sensing limit was about $1.5{\times}10^{-5}\;T$. The increase of electrical resistance by the magnetic field was ascribed to a modification of the Josephson junctions due to the penetrating magnetic flux into the superconducting material. Considering the observed properties of the superconductor with trapped magnetic flux, a magnetic sensor was fabricated to detect simultaneously both the intensity and the direction of the magnetic field.

• Journal of information and communication convergence engineering
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• 제6권4호
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• pp.411-416
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• 2008

When compose magnetic field curer by belt and band style and need by magnetic field ripple last month, produce self-discipline roof. Bred in muscle disease (lumbago, backbone disease, corpulence) back. Result that study, manufactured various variableness band style - magnetic field probe firstly. Can establish self-discipline treatment pulse price by disease secondly. Could seek correct variableness band punishment, - magnetic field probe relationship implementation and property in waist, and so on, shoulder, neck, arm, leg, ankle, wrist etc. by third. Could find variableness band style energy value that need in-magnetic field Probe's treatment by fourth. This research could design pulse of self-discipline in band form and apply each according to disease.

• Journal of Magnetics
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• 제18권3호
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• pp.326-330
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• 2013

Magnetic treatment of surface vessels and submarines (Deperm) is required to camouflage them against magnetic detection from enemy marine force. So far, deperm has been accomplished by applying an alternating magnetic field of which amplitude decreases linearly. However, the reduction of the residual flux density in the direction of magnetic field is not linear in the case of the linear protocol, since the ferromagnetic material used to construct a surface vessel, mainly Fe-C, shows a nonlinear behavior in an alternating magnetic field. This is one of main reasons to make an ordinary deperm protocol inefficient. In this paper, we propose the exponential deperming protocol and compare the exponential protocol to conventional linear protocol within the framework of deperm performance. We found out that step number could be reduced in the exponential protocol compare with in the linear protocol, because the larger numbers of deperm steps are dedicated in the irreversible domain process region on the magnetic hysteresis.

• Journal of Magnetics
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• 제16권4호
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• pp.453-456
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• 2011

Demagnetization for a tube sample which was made of a galvanized steel sheet was performed by applying a magnetic field with a decrement to remove the remanent magnetization of the material. An orthogonal fluxgate magnetic field sensor was used to measure a magnetic field created from a ferromagnetic material. To evaluate the remanent magnetization, the measured magnetic fields were separated into two magnetic field components by the remnant magnetization and the induced one. The horizontal and the vertical bias fields should be controlled separately during demagnetization to remove the horizontal and the vertical components of the remanent magnetization of the tube sample.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.1018-1021
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• 2003

This dissertation is reference to measure visual information about the configuration of magnetic field automatically and materialize the new magnetic field mapping system for the rapid and clear measure by using of the mediocrity orthogonal robot in the three- dimensional space required the measure of magnetic field concurrently. The measuring sensor is composed to be available for the measure of three-dimensional direction of magnetic field by vertically conjoining each of three hall sensors utilized of the hall effect and installed Gaussmeter, which is devised to receive the sensor result and the robot controller, away from the measuring robot in order to minimize the affection of magnetic field. Also, the controller and Gaussmeter are composed of Use interface, RS-232C and IEEE-488.2 communication. Interface system is written in NI's LabVIEW and composed to be able to set up a measuring area, the measuring number of times, two and three-dimensional graph, the velocity of robot and the magnetic field distribution graph of each element by inputting parameters. The materialized magnetic field mapping system expert the collection of the data easily and the effect of utilizing data.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.314.1-314.1
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• 2008