• New Physics: Sae Mulli
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• v.68 no.11
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• pp.1249-1261
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• 2018

The quantitative representation for the magnetic force of a cylindrical permanent magnet acting on a ferromagnetic cylindrical object was derived on the basis of magnetization theories, and the Gilbert and Ampere models of magnetism. The magnetic force derived in this study is directly proportional to the remanent magnetization magnetic field, the cross-sectional area of the permanent magnet, the saturation magnetic field, and the cross-sectional area of the ferromagnetic object and is inversely proportional to the square of the quantity related to the distance between the permanent magnet and the ferromagnetic object. The magnetic forces of an AlNiCoV cylindrical permanent magnet and a Ferrite cylindrical permanent magnet, both with a radius of 0.4 cm and a length of 7 cm, acting on ferromagnetic objects at distances farther than the radius were calculated to be less than 3.6711 N and 0.1857 N, respectively.

• The Journal of the Petrological Society of Korea
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• v.25 no.1
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• pp.85-88
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• 2016

The new rocks of the oceanic crust, like basalt, are created in the mid-oceanic ridge, and the magnetic polarities of the rocks are supposed to be oriented as following the Earth's magnetic field. An extensive magnetic survey of total field at sea level reveals mainly unusual north-south magnetic stripes parallel to the axis of the mid-oceanic ridge, especially in the Atlantic Ocean. From this stripes the Earth's magnetic field is considered as repeatedly 'flipped'(the N pole becoming the S pole, and vice versa) and many times over geological time. The discovery of stripes of alternately normal and reversed-magnetized rocks forming the ocean floor has been a key evidence for the sea-floor spreading, continental drift, and plate tectonics. This study introduces a simple apparatus to explain a possible mechanism of the magnetic reversal in the new oceanic crust, which makes a magnetic stripe adjacent to the mid-oceanic ridge. The apparatus shows a bar magnet effect of adjoined stripes to have a special magnetic polarity on the rocks in the center of the mid-oceanic ridge. The new magnetic stripe seems to be generated not only by Earth's magnetic field, but also by neighbored stripes in the mid-oceanic ridge, acting as a bar magnet.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.315-316
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• 2012

전기도금법으로 제조한 $Ni-TiO_2$ 복합체에 교반 속도가 전류효율에 미치는 영향을 연구하였다. 교반은 공기를 불어넣은 공기교반과 자석막대를 회전시킨 자석교반으로 나누어 실시하였다. 교반 속도는 공기교반의 경우에는 0.5, 1.0, 1.5 L/min, 자석교반의 경우에는 100, 200, 300, 400, 500 rpm으로 변화시켜 $Ni-TiO_2$ 복합체의 전류효율과 순수 니켈의 전류효율 변화를 관찰하였다. 순수 니켈의 경우 전류효율이 두 종류의 교반 방식 모두, 속도가 높아질수록 다소 감소하였으나, 그 폭이 크지 않았다. 반면, $Ni-TiO_2$ 복합체의 경우에는 교반 속도가 높아지면, 전류효율이 급격히 감소하였다. 특히, 공기교반의 경우에는 1.0L/min에서 1.5L/min으로 교반속도가 증가하면 전류효율이 크게 감소하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.122-129
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• 2008

This paper gives the experimental results for the effective precipitation of particulated matter(PM) below 1[${\mu}m$] of diameter using the electrostatic precipitator, which is designed by ourselves. In order to improve the precipitation efficiency, the vertical and parallel magnetic field to the electric field is applied simultaneously by arranging ferrite magnets. When the parallel magnetic field is applied, the precipitation efficiency does not improve in comparison with non-magnets. However, when the vertical magnetic field is applied, it is improved about 5[%] more than the case of non-magnetized ferrite plate used. In addition, when the magnets are installed at the center of ground plate electrodes, the precipitation efficiency is ranged from 17 to 32[%] under the applied voltage of 5[kV]. It is similar to the case of the magnet arrangement at the front part of ground electrode. Also, the precipitation efficiency is more improved by arranging magnets as the inside part and zigzag on the electrodes. Especially, large particles of 0.7 and 1[${\mu}m$] is more easily captured by electrostatic precipitator. Consequently, it is convinced that the vertical magnetic field is more desirable than parallel magnetic field on the electric field for the effective treatment of particulated matter.

• 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.