• Journal of Magnetics
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• 제18권2호
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• pp.105-110
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• 2013

The design model and key parameters of the material design for the control of induced magnetic flux at the near-field and efficient power transfer in a modified wireless power transfer (WPT) system with a large air gap of wireless electric vehicles were investigated through analytical simulations for magnetic vector and time-domain transient analysis. Higher saturation magnetic core with low core loss induced a stronger vertical magnetic field by the W-type primary coil in the WPT system with a gap of 20 cm at 20 kHz, which is shown from the vector potentials of the magnetic induction. The transient analysis shows that the higher magnetic fluxes through the pick-up cores lead to a linear increment of the alternating voltage with a sinusoidal waveform in the non-contact energy transfer system.

• 한국정보통신학회논문지
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• 제18권8호
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• pp.2051-2056
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• 2014

함정의 탈자결과 평가를 위한 자계신호의 분리방법에 대한 이론적 근거와 해저 면에 설치되는 사각코일로부터 발생하는 불균일한 자계가 분리결과에 미치는 영향을 측정 신호와 FEM해석을 통해 검토하였다. 측정신호는 제작된 모델함에서 발생하는 자계를 자계센서로 측정한 것이며 FEM 계산은 제작된 모델함과 동일한 형상으로 수행되었다. ILM(induced longitudinal magnetization) 신호와 IVM(induced vertical magnetization) 신호는 함정이 가지는 투자율과 지자계의 수평과 수직방향 성분에 의해 각각 발생하는 자화에 의한 것이며, PLM(permanent longitudinal magnetization) 신호와 PVM(permanent vertical magnetization) 신호는 함정의 영구자화의 수평성분과 수직성분에 의한 것임이 확인되었다. 또한 사각 코일의 수직방향의 자계는 균일한 지자계를 완전히 상쇄할 수 없어 사각코일의 면적에 가까운 크기를 가지는 함정 일수록 사각코일의 자계 불균일성의 영향을 크게 받게 됨을 알았다.

• 한국군사과학기술학회지
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• 제14권3호
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• pp.359-363
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• 2011

An orthogonal magnetic field is often used for a military vessel in the deperm process such as Flash D deperm protocol and Anhysteretic deperm protocol. The effect of the orthogonal magnetic field on a deperm performance was investigated for a sample with strain-induced magnetization and field-induced magnetization given to different direction. A 70mm wide, 110mm long and 0.25mm thick rectangular steel plate was bent to have U-shape and to generate a strong strain on the bottom region of U-shaped steel plate. Field-induced magnetization was attached by NdFeB permanent magnet. Demagnetization was performed by applying magnetic field with a step decrement from the first field(the first shot) under the action of DC bias field.

• 대한전기학회논문지
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• 제43권6호
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• pp.1001-1009
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• 1994

The present paper deals with a new developed sensor for measuring the time-varying magnetic fields and describes the experimental results of trasient magnetic field that takes place during the operations of electric appliance. The operation principle of the self-integrating magnetic field sensor by using coaxial cable is analyzed and a calibration investigation is carried out. The frequency bandwidth of the magnetic field measurement system is from 40 Hz to about 300 kHz. The magnetic field induced by the starting and/or operation of electric appliance mainly includes the odd harmonics such as the third, the fifth and the seventh harmonics. The magnetic field intensity caused during the operation of ultrasonic washer is inversely proportional to distance, this correspodns to induction component. As a result, it was known that the odd harmonics of magnetic field in the desing of electromagnetic shield employed for protecting electronic circuit and control devices have to be considered.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.183-186
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• 1998

Axial magnetic field generated by special electrode construction in vacuum interrupters is used to extinguish electric plasma arcs. This investigation by FDM should prove to what extent the magnetic field might influence on the arc expansion. The calculated results show that the stronger magnetic field induced the lesser radius of arc plasma. This study will help to offer good data in design of vacuum interrupters.

• Journal of Radiation Protection and Research
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• 제27권2호
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• pp.81-87
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• 2002

The interaction of low density extremely low frequency magnetic field (ELF MF) in the frequency of hypoxanthine-guanine phosphoribosyltransferase (HPRT) mutation induced by bleomycin and on the frequency of sister chromatid exchanges (SCEs) induced by 1,2,4-benzenetriol(BT) was demonstrated. CHO cells pretreated with bleomycin or 1,2,4-benzenetriol were exposed for 24hrs to a sinusoidal 0.8mT magnetic field at 60Hz. Frequency of HPRT mutation and SCEs were determined. ELF MF exposure led to a two-fold increase of the frequency of HPRT mutation induced by bleomycin. No increase of mutation frequency was observed by ELF MF alone ELF MF also increased the frequency of SCEs induced by BT while no Increase of SCE frequencies were observed by ELF MF alone. These results suggest that low density ELF MF field would art as an enhancer rather than as an initiator of mutagenic effects in CHO cell.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2001년도 International Symposium on Dietary and Medicinal Antimutgens and Anticarcinogens
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• pp.178-178
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• 2001

The interaction of extremely low frequency magnetic field (ELF-MF) on the frequency of micronuclei (MN) induced by benzo(a)pyrene (BP) in human lymphocytes was examined. A 60 Hz ELF-MF of 0.8 mT field strength was applied for 24 hours either alone or with the tumour initiator, BP. The frequency of MN induced by BP increased in a dose-dependent manner.(omitted)

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.36-40
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• 2010

In recent society, the electricity is so essential for the human lives. Lots of modern people take many cultural benefits owing to the development of the power systems, the cell phone, the electrical appliances, and etc. However, the problems related to the electromagnetic field generate as the side effects. Examples are the fault in the electric machinery due to the electromagnetic coupling, the fault in the communication devices due to the electromagnetic field around the power line equipments, and the effect upon the human beings due to the electromagnetic field, and etc. In this paper, we induce the vector equation about the magnetic field based on Biot-Savart law. We calculate the magnetic field at the surface of the high speed train with this induced equation and the current in the high speed railroad catenary wire. Finally, we calculate the magnetic field in the high speed train considering the material property like the permeability, the conductivity, and so on.

• Journal of Magnetics
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• 제17권3호
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• pp.210-213
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• 2012

To detect the surface and the opposite side cracks on iron specimen under AC and DC magnetic fields, the planar inductive coil sensors were employed. When the induced signals were measured, the planar inductive coil sensor and the magnetic field source were lifted off about 2 mm from the top surface of the specimen. AC magnetic fields and DC magnetic fields were applied to the specimens by single straight Cu coil and NdFeB permanent magnet, respectively. The detected signals at crack positions were good coincidence with those of the simulation results.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.394-394
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• 2013

The spin-orbit interaction has received great attention in the field of spintronics, because of its property and applicability. For instance, the spin-orbit interaction induces spin precession which is the key element of spin transistor proposed by Datta and Das, since frequency of precession can be controlled by electric field. The spin-orbit interaction is classified according to its origin, Dresselhaus and Rashba spin-orbit interaction. In particular, the Rashba spin-orbit interaction is induced by inversion asymmetry of quantum well structure and the slope of conduction band represents the strength of Rashba spin-orbit interaction. The strength of spin-orbit interaction is experimentally obtained from the Shubnikov de Hass (SdH) oscillation. The SdH oscillation is resistance change of channel for perpendicular magnetic field as a result of Zeeman spin splitting of Landau level, quantization of cyclotron motion by applied magnetic field. The frequency of oscillation is different for spin up and down due to the Rashba spin-orbit interaction. Consequently, the SdH oscillation shows the beat patterns. In many research studies, the spin-orbit interaction was treated as a tool for electrical manipulation of spin. On the other hands, it can be considered that the Rashba field, effective magnetic field induced by Rashba effect, may interact with external magnetic field. In order to investigate this issue, we utilized InAs quantum well layer, sandwiched by InGaAs/InAlAs as cladding layer. Then, the SdH oscillation was observed with tilted magnetic field in y-z plane. The y-component (longitudinal term) of applied magnetic field will interact with the Rashba field and the z-component (perpendicular term) will induce the Zeeman effect. As a result, the strength of spin-orbit interaction was increased (decreased), when applied magnetic field is parallel (anti-parallel) to the Rashba field. We found a possibility to control the spin precession with magnetic field.