• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.302.2-302.2
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• 2008

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.124-128
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• 1995

We have fabricated the vacuum magnetic device with a lateral field emitter arrays constructed on n-Si wafer, and investigated its magnetic characteristics. The device is consited to tip-arrayed emitter. gate and split-anode, The fabricated vacuum magnetic device has showed a good linearity of magnetic field and a high sensitivity compared with the conventional semiconductor magnetic device.

• Journal of Magnetics
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• v.19 no.2
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• pp.197-204
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• 2014

A transcranial magnetic stimulation device is a complicated appliance that employs a switching power device designed for discharging and charging a capacitor to more than 1 kV. For a simple transcranial magnetic stimulation device, this study used commercial power and controlled the firing angle using a Triac power device. AC 220V 60 Hz, the power device was used directly on the tanscranial magnetic stimulation device. The power supply device does not require a current limiting resistance in the rectifying device, energy storage capacitor or discharge circuit. To control the output power of the tanscranial magnetic stimulation device, the pulse repetition rate was regulated at 60 Hz. The change trigger of the Triac gate could be varied from $45^{\circ}$ to $135^{\circ}$. The AVR 182 (Zero Cross Detector) Chip and AVR one chip microprocessor could control the gate signal of the Triac precisely. The stimulation frequency of 50 Hz could be implemented when the initial charging voltage Vi was 1,000 V. The amplitude, pulse duration, frequency stimulation, train duration and power consumption was 0.1-2.2T, $250{\sim}300{\mu}s$, 0.1-60 Hz, 1-100 Sec and < 1 kW, respectively. Based on the results of this study, TMS can be an effective method of treating dysfunction and improving function of brain cells in brain damage caused by ischemia.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.11
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• pp.199-207
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• 1998

This paper presents the design and the control of three degree-of-freedom(DOF) fine positioning device based on an electro-magnetic force. The device is designed by use of a magnetic circuit theory and it is capable of fine motion due to the electro-magnetic force. The device consists of permanent magnets, yokes and coils. The magnetic fluxes generated from the permanent magnets constitute magnetic paths through steel, whereas the coils are arranged into the gap between two surfaces of the yokes. Therefore, by supplying current to the coils, the coils are capable of some motions due to Lorentz forces. For the optimal design of the actuating system, the system parameters are defined and investigated under the given constraints. From the system modeling in small displacement, three decoupled equations of motion are obtained. To get better performance of the system, a PID controller is implemented. Experimental results are presented in terms of time response and accuracy.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.8
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• pp.654-659
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• 2008

This paper is to suggest a concept design of the permanent magnet type magnetic resonance imaging (MRI) device based on the parameter optimization method. Pulse currents in the gradient coils will introduce the effect of eddy currents in the ferromagnetic material, which will worsen the quality of imaging. In order to equalize the magnetic flux in the MRI device for good imaging, the eddy current effect in the ferromagnetic material must be taken into account. This study attempts to use the design of experiment (DOE) and the response surface method (RSM) for equalizing the magnetic flux of the permanent magnet type MRI device using that the magnetic flux can be calculated directly using a commercial finite element analysis package. As a result, optimal shapes of the pole and the yoke of the PM type MRI device can be obtained. The commercial package, ANSYS, is used for analyzing the magnetic field problem and obtaining the resultant magnetic flux.

• Journal of Magnetics
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• v.19 no.4
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• pp.357-364
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• 2014

This study examined effect of a transcranial magnetic stimulation device with a commercial-frequency approach on the neuronal cell death caused ischemia. For a simple transcranial magnetic stimulation device, the experiment was conducted on an ischemia induced rat by transcranial magnetic stimulation of a commercial-frequency approach, controlling the firing angle using a Triac power device. The transcranial magnetic stimulation device was controlled at a voltage of 220 V 60 Hz and the trigger of the Triac gate was varied from $45^{\circ}$ up to $135^{\circ}$. Cerebral ischemia was caused by ligating the common carotid artery of male SD rats and reperfusion was performed again to blood after 5 minutes. Protein Expression was examined by Western blotting and the immune response cells reacting to the antibodies of Poly ADP ribose polymerase in the cerebral nerve cells. As a result, for the immune response cells of Poly ADP ribose polymerase related to necrosis, the transcranial magnetic stimulation device suppressed necrosis and had a protective effect on nerve cells. The effect was greatest within 12 hours after ischemia. Therefore, it is believed that in the case of brain damage caused by ischemia, the function of brain cells can be restored and the impairment can be improved by the application of transcranial magnetic stimulation.

• Proceedings of the Korean Magnestics Society Conference
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• 2015.05a
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• pp.161-163
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• 2015

The micro device, coil, and channel for the biosensor integrated with the GMR-SV device based on the antiferromagnetic IrMn layer was fabricated by the light lithography process. When RBCs coupled with several magnetic beads with a diameter of $1{\mu}m$ passed on the micro channel, the movement of RBC + ${\mu}Beads$ is controlled by the electrical AC input signal. The RBC + ${\mu}Beads$ having a micro-magnetic field captured above the GMR-SV device is changed as the output signals for detection status. From these results, the GMR-SV device having the width magnitude of a few micron size can be applied as the biosensor for the analysis of a new magnetic property as the membrane's deformation of RBC coupled to magnetic beads.

• Computers and Concrete
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• v.13 no.5
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• pp.649-657
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• 2014

In this paper, effects of magnetic water on different properties of cement paste including fluidity, compressive strength, time of setting and etc, has been studied in concrete laboratory of Sahand University of Technology. For production of magnetic water, three devices including an AFM called device(made in UAE), a device marked AC(made in Germany) and finally a device was designed and made in Concrete Laboratory of Sahand University of Technology) have been used. The results show that, intensity and direction of magnetic field, velocity and time of water passing through magnetic device, and amount and type of Colloidal particles have direct effects on properties of magnetic water and using such a water in making cement paste, increases its fluidity and compressive strength up to 10%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.242-242
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• 2007

무방향성 규소강판을 lamination core 형태로 제작하여 자기적 특성을 조사 하였다. 그 결과 1차, 2차 권선수가 400turns 시료에서 보자력(Hc)과 포화자속밀도(Bs)는 최대값을 나타내었고, 보자력은 0.05Oe, 포화자속밀도는 1.8T 이었다. 현재 국내에서 생산되고 있는 무방향성 규소강판의 자속밀도값 보다 더 우수한 강을 나타내었으며, 열화특성이 자기적 특성에 미치는 영향을 통해 고효율 무방항성 규소강판 개발의 가능성을 확인하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1803-1808
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• 2010

Electric railway system consists of rolling stock, track, signal and catenary system. ATP system in railway signaling system is the important one grasping the position and velocity of a train. The wayside device of ATP system is installed between rails. Recently, the research about increasing train speed has been developed in total departments of the railroad systems. The study on the information transmission between on-board device and wayside device is required for increasing the train speed in the ATP system. When the train speed is increased as to same transmission distance, the problem on information transmission occurs because the transmission time is decreased. In case that the transmission distance is extended, the transmission time is decreased with respect to the train speed. Therefore, we have to define the standard magnetic field intensity as to the train speed in order to transmit correctly telegram. In this paper, the transmission distance for the telegram is suggested on the basis of the train speed. Also, the standard magnetic field intensity from the wayside device to on-board device is proposed by using transmission distance regarding the train speed in the ERTMS/ETCS system by using Matlab program. Also, BER according to the train speed is presented by calculating electric field intensity from the magnetic field intensity.