• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.188-189
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• 2007

Axial magnetic field was applied into the hollow anode of plasma torch for the purpose of extension of electrode lifetime. The average arc voltage increased because the arc column became longer, the arc voltage ripple frequency became low. The steady state of arc voltage was removed by applied magnetic filed. The lifetime of electrode was over 1000 hours which is 100 times longer than operation without magnetic field.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.616-619
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• 2000

It is important to control the plasma characteristics for high quality plasma process. Recently, a novel method proposed by us, named as Enhanced-ICP, using periodic weak time-varying axial magnetic field added to a normal ICP source, has improved etch characteristics much. Variation of plasma characteristics according to the frequency of time-varying axial magnetic field have been measured and analyzed.

• 지구물리와물리탐사
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• 제25권1호
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• pp.38-43
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• 2022

화산의 화도나 불발탄과 같이 축 대칭을 갖지만 단면의 반지름이 변하는 경우 대칭축에 수직인 얇은 원판들의 반응을 더하여 모델링하는 것이 효율적이다. 이런 모양의 이상체에 대한 자력 및 자력 변화율 텐서 모델링을 위해서는 얇은 원판에 대한 해석해가 필수적이다. 따라서 이 논문에서는 원판형 이상체에 대한 벡터 자력과 자력 변화율 텐서 반응식을 유도하였다. 벡터 자력은 중력 변화율 텐서를 자력으로 변환하는 포아송 관계식을 이용하여 원판형 이상체의 기존 중력 변화율 텐서로부터 유도하였다. 자력 변화율 텐서는 직교 좌표계의 미분 관계식을 원통 좌표계로 미분 관계식으로 변환한 후 벡터 자력을 미분하여 유도하였다. 벡터 자력과 자력 변화율 텐서는 원판형 이상체의 축 대칭성을 이용한 립쉬츠-한켈(Lipschitz-Hankel) 적분을 기반으로 구하였다.

• 한국결정성장학회지
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• 제3권1호
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• pp.1-11
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• 1993

초크랄스키 법에 의한 실리콘 단결정 성장시 액상내의 난류 특성 억제 및 산소, 첨가제 등의 제어를 위해 보통 자기장을 걸어주고 있으며 본 연구에서는 축방향 자기장을 걸어주었을 경우 나타나는 자장의 효과를 수치적으로 계산하였다. 자기력의 증가에 따라 액상내의 유속의 크기는 상당히 억제되었다. 자장의 크기가 증가함에 따라 중심축 부근에서 상승하는 유동의 속도가 감소하기 때문에 S/L 응고계면은 점점 평탄해졌으며, B=0.3 Tesla에서 액상내의 온도 분포는 중심축 부근을 제외하고는 오직 전호 효과로만 계산된 결과와 거의 유사하였다. 또한 고상 및 액상 표면을 통한 열방출량 중 Ar 가스에 의한 열방출량은 3% 미만이었으며 대부분의 열량은 복사를 통해 방출되었다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권5호
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• pp.309-314
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• 1999

The magnetized helical resonator plasma etcher has been built. Electron density and temperature were measured as functions of rf source power, axial magnetic field, and pressure. The results show electron density increases as the magnetic field increases and reached $2\times1012cm^{-3}$,/TEX>. The oxide etch rate and selectivity to polysilicon were investigated as the above mentioned conditions and self-bias voltage. We can obtain the much improved oxide etch selectivity to polysilicon (60 : 1) by applying the external axial weak magnetic field in magnetized helical resonator plasma etcher.

• 한국산학기술학회논문지
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• 제16권10호
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• pp.6453-6457
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• 2015

본 논문에서는 솔레노이드의 자기 이론과 시뮬레이션을 통해 해석의 정확성을 검증하였다. 솔레노이드는 간단한 구조와 빠른 응답성을 바탕으로 기계 산업, 의료 등의 분야에 활발히 사용되어지고 있다. 솔레노이드 엑츄에이터는 전자기력을 활용하며 전류를 인가시키면 자기장이 형성되어 자기력을 발생시키고 플런저를 직선운동 또는 회전운동으로 구동을 시키는 장치이다. 이론 해석은 Biot-Savart's law를 통해 축방향 및 반경방향 자기장 (Magnetic flux density, B)의 값을 구했으며, 임의의 점 P에서의 자기장 값도 계산하였다. Ansys의 Magnetostatic Analysis를 이용하여 해석 시뮬레이션을 진행하였고, 그 결과를 비교하여 이론과 해석의 유사성을 살펴보았다. 비교 결과를 통해 오차 범위 안에서 error값이 존재함을 알 수 있었고, 따라서 정확성을 검증할 수 있었다.

• 한국초전도ㆍ저온공학회논문지
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• 제5권1호
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• pp.97-101
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• 2003

When HTS tapes are used in power application, they are used by winding form, such as, a pancake and a solenoid. When AC current is applied to the coil, Ac magnetic field is generated in winding. This AC magnetic field acts as an external magnetic field and makes loss. In this paper the radial magnetic field component ($B_r$) and the axial magnetic field component ($B_z$) in a pancake and a solenoid were calculated by numerical analysis method and compare with measured value. AC losses of a short sample were calculated by Norris equation and n numerical analysis based on Brandt equation. AC losses of the pancake coil and the solenoid coil were also calculated.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2500-2505
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• 2007

The vacuum interrupter (VI) is used for medium-voltage switching circuits due to its abilities and advantages as a compact and environmental friendly circuit breaker. In general, the application of a sufficiently strong axial magnetic field (AMF) permits the arc to be maintained in a diffused mode to a high-current vacuum arc. A full understanding of the vacuum arc physics is very important since it can aid to improve the performance of vacuum interrupter. In order to closely examine the vacuum arc phenomena, it is necessary to predict the magnetohydrodynamic (MHD) characteristics by the multidisciplinary numerical modeling, which is coupled with the electromagnetic and hydrodynamic fields, simultaneously. In this study, we have investigated the electromagnetic behaviors of high-current vacuum arcs for two different types of AMF contacts, which are coil-type and cup-type, using a commercial finite element analysis (FEA) package, ANSYS. The present results are compared with those of MAXWELL 3D, a reliable electromagnetic analysis software, for verification.

• 한국초전도ㆍ저온공학회논문지
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• 제18권1호
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• pp.50-54
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• 2016

In this paper, a hybrid method is proposed to design an air-core superconducting solenoid system for 6 T axial uniform magnetic field using Niobium Titanium (NbTi) superconducting wire. In order to minimize the volume of conductor, the hybrid optimization method including a linear programming and a nonlinear programming was adopted. The feasible space of solenoid is divided by several grids and the magnetic field at target point is approximated by the sum of magnetic field generated by an ideal current loop at the center of each grid. Using the linear programming, a global optimal current distribution in the feasible space can be indicated by non-zero current grids. Furthermore the clusters of the non-zero current grids also give the information of probable solenoids in the feasible space, such as the number, the shape, and so on. Applying these probable solenoids as the initial model, the final practical configuration of solenoids with integer layers can be obtained by the nonlinear programming. The design result illustrates the efficiency and the flexibility of the hybrid method. And this method can also be used for the magnet design which is required the high homogeneity within several ppm (parts per million).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2515-2518
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• 2008

The vacuum interrupter (VI) is widely used in medium-voltage switching circuits due to its abilities and advantages as an environmental friendly circuit breaker. An understanding of the vacuum arc flow phenomena is very important for improving the performance of vacuum interrupter. In order to closely examine the vacuum arc phenomena, it is necessary to predict the magnetohydrodynamic (MHD) characteristics by the multidisciplinary numerical modeling, which is coupled with the electromagnetic and the thermal flow fields, simultaneously. In this study, we have investigated arc plasma constriction phenomena and an effect of AMF on the arc plasma with the high-current vacuum arcs for the cup-type AMF electrode by using a commercial finite element analysis (FEA) package, ANSYS. The simulation results applied with various AMFs and constant Joule heat generation show that strong axial magnetic field (AMF) permits the arc to be maintained in a diffused mode to a high-current vacuum arc. However, further studies are required on the two-way coupling method and radiation model for arc plasma in order to accomplish the advanced analysis method.