• Advances in Computational Design
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• v.7 no.1
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• pp.57-68
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• 2022

A simulation study of the distribution of magnetic flux induced by a U-shaped electromagnet into a two-layer massive object with variations in the depth and properties of the surface layer has been carried out. It has been established that the hardened surface layer "pushes" the magnetic flux into the bulk of the magnetized object and the magnetic flux penetration depth monotonically increases with increasing thickness of the hardened layer. A change in the thickness and magnetic properties of the surface layer leads to a redistribution of magnetic fluxes passing between the poles of the electromagnet along with the layer and the bulk of the steel object. In this case, the change in the layer thickness significantly affects the magnitude of the tangential component of the field on the surface of the object in the interpolar space, and the change in the properties of the layer affects the magnitude of the magnetic flux in the magnetic "transducer-object" circuit. This difference in magnetic parameters can be used for selective testing of the surface hardening quality. It has been shown that the hardened layer pushes the magnetic flux into the depth of the magnetized object. The nominal depth of penetration of the flow monotonically increases with an increase in the thickness of the hardened layer.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1549-1551
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• 2004

The Electromagnetic properties in BiPbSrCaCuO superconductor was studied. In the measurement of current-voltage characteristics, a voltage across the superconducting sample was observed on applying an external magnetic field. The voltage continues to appear the removal of the magnetic field. The appearance of the voltage is ascribed to the trapping of magnetic flux. Depanding on the direction of applied magnetic flux less than 2.5${\times}$10-5 T, the voltage in the magnetized sample increases or decreases. It is considered that mechanism of voltage occurrence can be explained by applying filament model.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.302-305
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• 2000

It is important to control the electron energy distribution to have high quality plasma process. A conventional inductively coupled plasma(ICP) source with 13.56MHz power is not adequate for low damage sub-half micron patterning process due to higher electron temperature. Only the pulsed plasma technique seems to provide low electron temperature, and thus low process damage. Recently, a novel method proposed by us, named as ‘Enhanced-ICP’, which uses periodic weak axial magnetic field added to a normal ICP source, has shown great improvement in etch characteristics. changes of plasma characteristics according to the frequency of time-varying axial magnetic field have been observed by probe-time-averaged Langmuir probe.

• Journal of Magnetics
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• v.19 no.1
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• pp.84-89
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• 2014

This paper presents an analytical prediction and experimental verification of the electromagnetic performance of a parallel magnetized surface-mounted permanent magnet (SPM) motor having a fractional number of slots per pole combination. On the basis of a two-dimensional (2-D) polar coordinate system and a magnetic vector potential, analytical solutions for flux density produced by the permanent magnets (PMs) and stator windings are derived. Then, analytical solutions for back-electromotive force (emf) and electromagnetic torque are derived from these field solutions. The analytical results are thoroughly validated with 2-D nonlinear finite element (FE) analysis results. Finally, the experimental back-emf and electromagnetic torque measurements are presented to test the validity of the analysis.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.131.1-131.1
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• 2015

플라즈마 진단법으로서 컷오프 탐침과 랑뮤어 탐침은 다양한 분야에서 많은 연구가 진행되었다. 하지만 고밀도 및 균일성 관점에서 많은 이점을 가지고 있는 자화유도결합플라즈마에서 컷오프 탐침의 적용 가능성에 대한 연구는 많이 부족하다. 본 연구에서는 두 가지 탐침법을 이용하여 전자밀도를 비교하고 각각의 특성을 분석하였다. 먼저 랑뮤어 탐침법을 이용하여 RF파워, 압력, 외부자기장에 따른 플라즈마 변수(전자밀도, 전자온도, 플라즈마 전위)를 측정하였다. 외부자기장을 인가하였을 때 전자구속으로 인하여 전 영역의 전자밀도는 증가하였지만 R방향의 전자밀도 분포는 균일하지 않았다. 반면 전자온도는 외부자기장을 인가하였을 때 챔버 중심에서 감소하였으며, 챔버 끝에서 전자온도는 증가하였다. 즉, R방향의 전자온도 분포는 U형태가 나타났다. 또한 컷오프 탐침으로 전자밀도를 측정한 결과 비교적 낮은 $10^{11}/cm^3$ 이하에서 정확한 컷오프 주파수를 확인하여 전자밀도를 구할 수 있었으며, 그 이상의 전자밀도를 갖는 경우 동축케이블의 손상 문제로 인하여 신뢰성 있는 결과를 얻기는 힘들다. 현재 이 문제를 해결하기 위한 연구가 지속적으로 진행 중이다.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.601-603
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• 2004

We present the results of the linear analysis for the Parker-Jeans instability in the magnetized gas disks including the effect of cosmic-ray diffusion along the magnetic field lines. We adopted an uni-formly rotating two temperature layered disk with a horizontal magnetic fields and solved the perturbed equations numerically. Fragmentation of gases takes place and filamentary structures are formed by the growth of the instability. Nagai et al. (1998) showed that the direction of filaments being formed by the Parker-Jeans instability depends on the strength of pressure outside the unperturbed gas disk. We found that at some range of external pressures the direction of filaments is also governed by the value of the diffusion coefficient of CR along the magnetic field lines k.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.131-137
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• 1999

Under magnetism , as the magneticfluid is being itself magnetized, increase the apparent viscosity because of its body force and has the magnetic characteristics in response ot magnetism, the magnetic fluid is getting attention in various field. The magnetic fluid has the fluidity, which is a special characteristics of fluid and the magneticism , which is a special one of solid. Using this characteristics, this study has been proceeded to show the basic data for developing of a viscous damper with magnetism fluid as hydraulic fluid. Experimental study shows that the application of magnetic field is effective reducing the resonance characteristics of the spring-mass system.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.197-199
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• 2006

This paper presents a analytical field solutions for the general class of Linear Brushless DC(LBLDC) motors with PM mover and 3-phase winding stator. In our magnetic field analysis, we have adopted an approach which can treat both magnetized material and winding from the each field analysis by magnetic vector potential considering 2-Dimensional slot modeling. Therefore, we give accurate analytical formulas and object function for design and parameters estimation by its magnetic field.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.127-129
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• 1996

A 3-dimensional analysis is desired for a magnet of magnetically levitated vehicle because the geometrical shape of the magnet is complicated and nonsymmetric. A FEM package of FLUX3D is used to analyze the characteristic of the magnet. Various quantities could be observed like levitation force, flux density distribution along the air gap, edge and fringing effect, leakage flux pattern, etc. The simulation results from FLUX3D are compared with those of 2-D analysis and test results. There are a little difference between results due to the boundary conditions and magnetized B-H curve of the core.

• Journal of Acupuncture Research
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• v.30 no.5
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• pp.95-105
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• 2013

Objectives : The purpose of this study is to examine the preparing methods of the traditional acupuncture needle and to interpret the electromagnetic meaning intervened in them. Methods : The overall manufacturing processes of the acupuncture needles in ancient books were surveyed. And the facts that special functional activities were carried out in common in the preparing processes were detected. The reproduction tests for the detected former functional activities were followed. Results : According to the ancient medical books, the traditional acupuncture needles were treated with the magnet through the preparing processes. The reproduction tests provided the fact that the ferromagnetic iron needles treated with the magnet were enhanced their magnetisms. And major techniques of the ancient supplementation and draining can be interpreted as magnetic or induced electromagnetic actions. Conclusions : Considering the electromagnetic characteristics of human body, the magnet treated ferromagnetic iron needles of ancient era and magnetic or induced electromagnetic interpretable manipulation techniques are the historical evidences of magnetic activities of acupuncture. So modern acupuncture therapy should be understood, studied, and reinterpreted as an electromagnetic viewpoint.