• Proceedings of the Korean Magnestics Society Conference
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• 2000.09a
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• pp.200-206
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• 2000

We have investigated the activation magnetic moment, which characterizes the basis magnetic moment acting as a single magnetic particle during magnetization reversal. The activation magnetic moment was measured from each local area on continuous ferromagnetic thin films, by analyzing the magnetic field dependence of magnetization reversal of the corresponding local area based on a thermally activated relaxation process. It was found that the activation magnetic moment was nonuniform on submicrometer scale; the fluctuation increased with increasing the number of layers in Co/Pd multilayers. The distribution could be well analyzed by exp($\delta$m$\^$3/2/), where $\delta$m is the deviation of the activation magnetic moment from the mean value.

• Journal of Magnetics
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• v.6 no.2
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• pp.70-72
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• 2001

We have investigated the activation magnetic moment, which characterizes the basic magnetic moment acting as a single magnetic particle during magnetization reversal. The activation magnetic moment was measured from each local area on continuous ferromagnetic thin films, by analyzing the magnetic field dependence of magnetization reversal of the corresponding local area, based on a thermally activated relaxation process. It was found that the activation magnetic moment was nonuniform on a submicrometer scale; the fluctuation increased with increasing the number of layers in Co/Pd multilayers. The distribution could be well described by exp($\delta m^{3/2}$), where $\delta$m is the deviation of the activation magnetic moment from the mean value.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.489-494
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• 2008

The measurement of magnetic field is performed about DC and AC magnetic field in electric railway line. The test point is cap, on the converter/inverter box, on the traction motor and on the SIV, the height of measurement is bottom and 60 cm height. In case of AC magnetic field, the selected specific frequency is measured on the converter/inverter box. The AC magnetic field is checked and analysis through BNC output, DAQ cad and notebook PC.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.4
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• pp.339-344
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• 2007

Safety of large scale cable in bridge is very important because it may cause the unwanted catastrophic failure. Although the proof load were considered at the design stage, its soundness must be monitored continuously because the cable may be broken out without warning by the variable external load. The cable tension of in-use structures has been mainly measured by the resonance method and its use has been limited because of relatively large measurement uncertainty. Recently a new magnetic method was developed and its reliability is known to be good for evaluating the cable tension. In this study a system which can deliver the calibrated load to the cable was developed and the measurement reliability of developed magnetic sensor according to the change of external load was analyzed quantitatively. The effect of magnetization frequency, bias magnetic field, and temperature on the sensor output was also evaluated.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.2055-2058
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• 2004

This paper formulates a yaw angle determination algorithm for earth-point satellite. The algorithm based on vector observation, is implemented with the limited vector measurements. The proposed algorithm doesn't require gyro measurement data but magnetic sensor measurement data. In order to confirm the usefulness of the proposed method, we investigate the simulated telemetry data of the KOMPSAT-2, a satellite that is scheduled to be launched into a 685km altitude sun synchronous circular orbit in 2005.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.304-307
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• 2003

Usually, the thrust of a Linear Pulse Motor(LPM) is calculated by magnetic equivalent circuit modelling method. Analytical thrust deviation exists to calculating magnetic flux density by using Permeance Modelling Method, Finite Element Method, and Velocity Electric Motive Force method. For calculating accuracy thrust by using these every method, tire thrust is calculated and compared by Lorentz Force method, Magnetic coenergy Method, and Maxwell correspondence forte Method. And that becomes Important factor at the comparison of each capacity and parameter of motor. So this study wants to compare and analyze measurement data and calculating data of the static thrust of LPM. and then we can get more accuracy method, calculating the static thrust of LPM.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.817-819
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• 2007

The purpose of this work is to develop a measurement system of the pendulum test with minimal restriction of experimental environment and little influence of noise. In this work, we developed a vision system without any line between markers and a camera. The system performance is little influenced by the experimental environment, if light are sufficient to recognize markers. For the validation of the system, we compared knee joint angle trajectories measured by the developed system and by the magnetic sensor system during the nominal pendulum test and the maximum speed voluntary knee joint rotation. The joint angle trajectories of the developed system during both tests matched well with those of the magnetic system. Therefore, we suggest the vision system as an alternative to the previous systems with limited practicality for the pendulum test.

• Journal of the Korean Magnetics Society
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• v.1 no.1
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• pp.30-36
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• 1991

A measurement system for magnetic anisotropy was built. The torque acting on the disc or sperical samples placed in uniform magnetic field was detected with a capacitive transducer which is connected with a transformer ratio-arm bridge. The output of the bridge was amplified with a lock-in amplifier. The cubic anisotropy constant for (100) of 3% Si-Fe was $3.3{\times}10^{4}\;J/m^{3}$. The calibration for the system was carried out with the shape anisotropy of a thin Ni wire.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.6
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• pp.136-144
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• 1996

We developed a part of stroke sensing cylinder for position control of automatic excavator and its measurement system. In this paper, for development of stroke sensing cylinder, we consist of 2-axis control instrument system with Hall sensor. A performance of piston rod with magnetic scales is evaluated by the developed measurement system. Furthermore, the position control for good performance of instrument system is achieved by a sliding mode control which is a new method diminishing the chattering in that control by setting 2-dead band along the swtching line. The unknown parameters for sliding mode control are estimated by the signal compression method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.554-558
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• 2002

A magnetostrictive sensor is used to measure stress waves propagating in a ferromagnetic cylinder without physical contact. The performance of a magnetostrictive sensor is affected most significantly by the bias magnetic field applied around the measurement location. The goal of this paper is to carry out the topology optimization of the bias magnet and yoke assembly to maximize the sensor output for traveling bending waves. We will use the multi-resolution topology optimization strategy to find the assembly of the bias magnet and the yoke that is easy to realize. The effectiveness of the present design is confirmed by an actual measurement of the sensor signal with the proposed bias magnet and yoke configuration.