• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.8
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• pp.99-105
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• 2011

This paper is about the design of 3-axis magnetic sensor module which detects parking and moving vehicle. For the sensor module, MR Sensor from Honeywell of which maximum measurement range is ${\pm}2$[G] is used. It also consisted of amplifier and sensor filter and fabricated $30{\times}50$[mm] PCB. Fabricated sensor module produced helmholtz coil of which the length is 1.2[m] of 3-axis to know the performance. It installed sensor module at the center and measured the detected magnetic field. In result, 3-axis were detected as 0.2~0.3[mG] and the drift of the fluctuation of magnetic field was stabilized at 0.03[mG] unit. For the performance evaluation of the vehicle detection, after the entry and parking of the vehicle, variation of magnetic field was measured as 0.323~0.695[G] which the average 0.5[G] of the earth magnetic field was the center and the range of variation was confirmed as 0.37[G]. Therefore, the designed magnetic sensor can be used as the vehicle detection sensor module.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.89-89
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• 2002

Purpose： To report initial experience and evaluate feasibility of cervical carotid artery contrast-enhanced MR angiography (CEMRA) using whole body coil at 3.0T Method： Twenty-eight patients (14 male, ages 41-80, mean age 63) underwent CEMRA at the 3.0T using whole body coil and 3D-FSPGR (TR/TE 6.6/l.3 msec, FA 30, thickness 1.3mm), and thirty patients (17 male, ages 30-80, mean age 57) underwent CEMRA at the 1.5T using Helmholtz neck coil and 3D FLASH sequence (TR/TE 3.8/l.4msec, FA 35, thickness 1mm). At both 1.5 and 3.0T, a power injector (Spectris) injected 20m1 of gadolinium to the right or left antecubital vein at a rate of 3mL/s. All CEMRA cases were accepted by one neuroradiologiest. We measured the signal intensities at the bifurcation of common carotid artery (CCA), vertebral artery (V2) and two surrounding tissues (ST) and noise at the background in all patients, and also compared contras-to-noise ratios (CNR) of CCA/ST and V2/ST at 3.0 and 1.5T

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.2 no.2
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• pp.69-78
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• 1991

전자파장해 측정에 사용되는 대표적인 측정시설에는 접지면(ground plane)을 갖춘 야외시험장 (open area test site), 전자파반무향실(semianechoic chamber), TEM(transverse Electromagnetic) cell, 평행판선로(parallel plate line), 헬름홀츠코일(Helmholtz coil), 전자파잔향실(reverberating chamber) 등이 있으며, 이러한 시설은 시험대상기기의 크기, 주파수대역, 적용규격의 규제치, 측정하고자 하는 전자기장의 형태 및 편파면, 그리고 시험신호의 전기적 특성(주파수영역 또는 시간영역) 등을 고려하여 선택되고 구성되 어야 한다. 실제로 시험장소를 건설하는데 막대한 비용이 소요되고, 큰 측정오차를 유발시킬 수 있기 때문에 매우 신중 하게 설계, 구성하여야 한다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.13-17
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• 2003

In this paper, the design parameters for the magnetic field source at extremely low frequency are proposed. This facility can be used for in vivo experiments with small animals to investigate biological response to the driving magnetic fields. In case that the exposed animals are motionless, the animals may be affected by the directivity of driving field. To avoid this effect, a 2-axis ELF magnetic field driving apparatus was designed, The optimum location and number of turns of each coil were obtained by numerical analysis. Applying these data to the MATLAB code (for computation), the magnetic field distribution was obtained. The calculation result for a well-designed facility showed that the space in which the amplitude of the magnetic field lies within the 95% of the magnetic field distribution was more than 60% of each axis length.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.8
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• pp.871-877
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• 2003

In this paper, the design parameters for the magnetic field source at extremely low frequency are proposed. This facility can be used fur in vivo experiments with small animals to investigate biological response to the driving magnetic fields. In case that the exposed animals are motionless, the animals may be affected by the directivity of driving field. To avoid this effect, a 2-axis ELF magnetic field driving apparatus was designed. The optimum location and number of turns of each coil were obtained by numerical analysis. Applying these data to the MATLAB code(for computation), the magnetic field distribution was obtained. The calculation result fur a well-designed facility showed that the space in which the amplitude of the magnetic field lies within the 95 % of the magnetic field distribution was more than 60 % of each axis length.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.2
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• pp.349-354
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• 2015

This paper is about utilizing magnetic sensor to measure magnetic signal and analyze the form of magnetic signal for vehicle detection. For magnetic sensor, MR sensor from Honeywell company was used, and Helmholtz coil of which 3 axis' length is 1.2 m was manufactured to check the capability of the sensor and estimate its ability to detect the magnetic field. Vehicle detection was performed in following steps: installing sensor in road lane and non-road lane; estimating magnetic field when the vehicle is run by the driver; and estimating magnetic field of 7 different vehicles with different sizes. Also, sensor was installed at SUV and small-sized vehicle's park and non-park area to analyze the form of magnetic field. Lastly, the form of magnetic field made by different parts of the vehicle was analyzed. Based on the analysis, the form of magnetic field's magnetic peak value was bigger for road lane than non-road lane, complicated form was useful to distinguish the road lane above the installed sensor and the location of the running car, and the types of vehicle could be sorted because the variance of the magnetic field was bigger for bigger size of the vehicle. Also, it was confirmed that the forms of vehicle in parts-by-parts estimates.

• Transactions on Electrical and Electronic Materials
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• v.10 no.2
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• pp.35-39
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• 2009

A novel Helmholtz coil inductively coupled plasma(H-ICP) etcher is proposed and characterized for deep nano-scale CMOS technology. Various hardware tests are performed while varying key parameters such as distance between the top and bottom coils, the distance between the chamber ceiling and the wafer, and the chamber height in order to determine the optimal design of the chamber and optimal process conditions. The uniformity was significantly improved by applying the optimum conditions. The plasma density obtained with the H-ICP source was about $5{\times}10^{11}/cm^3$, and the electron temperature was about 2-3 eV. The etching selectivity for the poly-silicon gate versus the ultra-thin gate oxide was 482:1 at 10 sccm of $HeO_2$. The proposed H-ICP was successfully applied to form multiple 60-nm poly-silicon gate layers.

• Journal of the Korean Vacuum Society
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• v.12 no.1
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• pp.1-6
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• 2003

An axial electron beam gun system, which emits the electron beam power of 50 kW, has been manufactured. The electron beam gun consists of two parts. One is the electron beam generation part. including the filament, cathode, and anode. The maximum beam current is 2 A and the acceleration voltage is 25 kV. The other part includes the focusing-, deflection-, and scanning coils. The beam diameter and ham trajectory can be controlled by these coils. The characteristic of each part is measured ior the optimum condition of evaporation process. Moreover, Helmholtz coil is installed inside the vacuum chamber to adjust the incident angel of the beam to the melting surface for the maximum evaporation. We report on the evaporation rates for zirconium(Zr) and gadolinium(Gd) metals which have the high melting temperatures.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1300-1305
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• 2009

The various electromagnetic based actuation(EMA) methods have been proposed for actuating microrobot. The advantage of EMA is that it can provide wireless driving to microrobot. In this reason a lot of researchers have been focusing on the EMA driven microrobot. This paper proposed a swimming microrobot driven by external alternating magnet field which is generated by two pairs of Helmholtz coils. The microrobot has a fish-like shape and consists of a buoyant robot body, a permanent magnet, and a fin. The fin is directly linked to the permanent magnet and the magnet is swung by the alternating magnet field, which makes the propulsion and steering power of the robot. In this paper, firstly, we designed the locomotive mechanism of the microrobot boy EMA. Secondly, we set up the control system. Finally, we demonstrated the swimming robot and evaluated the performance of the microrobot by the experiments.

• Journal of the Korean Magnetics Society
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• v.8 no.6
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• pp.388-394
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• 1998

We designed and fabricated an improved null-type torque magnetometer for measuring magnetic anisotropy of magnetic materials. This torque magnetometer has a measurement range of $~{\pm}15$ dyne.cm, and the range can be controlled. Resolution is ~0.0005 dyne.cm. Noise level is less than 0.01 dyne.cm with one measurement, and less than 0.004 dyne.cm with 10 averaged measuremets. The precision is less than 0.5 %. In contrast to typical null-type torque magnetometers, we placed a small ferrite magnet in the Helmholtz coil, instead of placing coil in the permanent magnet. From this novel sturucture, we can design a geometrically isotropic and relatively light-weight sample rod. Also, we can prevent the effect of input and output lines of coil exposed in the magnetic field in torque meter. Consequently, our novel null-type torque magnetometer can have a better sensitivity, faster response time, and smaller distortion of torque curve than commercially available torque magnetometers.