• 대한안전경영과학회지
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• 제11권4호
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• pp.311-317
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• 2009

In this paper deals with behavior of the magnetic abrasive using Ba-Ferrite on polishing characteristics in a new internal finishing of STS304 pipe applying magnetic abrasive polishing. The magnetic abrasive using Ba-Ferrite grain WA used to resin bond fabricated low temperature. And Ba-Ferrite of magnetic abrasive powder fabricated that Ba-Ferrite was crused into 200 mesh. The previous research have made an experiment in the static state the movement of magnetic abrasive grain is nevertheless in the dynamic state. In this paper, We could have investigated into the changes of the movement of magnetic abrasive grain. In reference to this result, we could have made the experiment which is set under the condition of the magnetic flux density, polishing velocity according to the form of magnetic brush.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.565-568
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• 2003

In this paper we deal with behavior of the magnetic abrasive using Ba-Ferrite on polishing characteristics in a new internal finishing of STS304 pipe applying magnetic abrasive polishing. The magnetic abrasive using Ba-Ferrite grain WA was used to resin bond fabricated at low temperature. And Ba-Ferrite of magnetic abrasive powder was crused into 200 mesh. The previous research made an experiment in the static and the dynamic state on the movement of magnetic abrasive grain. In this paper. We investigated into the changes of the movement of magnetic abrasive grain. In reference to this result. we have made the experiment which is set under the condition of the magnetic flux density. polishing velocity according to the form of magnetic brush.

• 한국진공학회지
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• 제8권2호
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• pp.172-179
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• 1999

The axial distributions of plasma density in a helical resonator plasma with the external magnetic field have been measured using Langmuir probes. Net RF power is set to 200W and chamber pressure is varied from 0.4 mTorr to 100mTorr there are three kinds of eternal magnetic field structure applied on the helical resonator plasma. One is a uniform magnetic field, the second is a positive gradient magnetic field and the third is a negative gradient magnetic field. In the three magnetic field structures, the negative gradient magnetic field is found to show the highest increase in plasma density on the substrate compared with other magnetic structures. Plasma density profile in helical resonator is well consistent with electromagnetic field pattern obtained by computer simulation. It is also found that axial magnetic fields do not affect plasma density distribution in the plasma reactor region, but induce the increase of plasma density in the process chamber region. In order to avoid the nonuniformity of radial density profile, weak magnetic fields under 100G are applied.

• 한국결정성장학회지
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• 제8권4호
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• pp.555-562
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• 1998

비균일 자장이 도가니에 인가되어 있는 상황에서 정상상태의 Czochralski 유동장과 비정상상태의 산소농도장에 대한 연구가 수치해석적인 방법으로 연구되었다. 여기에서 기준 자장의 세기가 B=0.1T, 0.2T, 0.3T의 경우에 대한 연구가 수행되었다. 가열에 의한 부력의 효과와 자유표면의 표면장력에 의한 열모세관 효과에 의하여 유발되는 자오면 유동은 비균일 자장에 의하여 차등적으로 억제되고 있다. 자자의 세기가 증가하면 자오면 유동에서 발생하는 순환류의 중심은 결정으로 접근하며, 순환류의 크기도 작아진다. 결정으로 흡수되는 산소의 세기가 클수록 낮아지며 농도분포는 균일해지는 경향을 갖는다.

• 한국초전도ㆍ저온공학회논문지
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• 제11권4호
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• pp.33-36
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• 2009

An air gap between the pancake windings was provided in this paper to increase the central magnetic field of a high temperature superconducting (HTS) magnet consisting of pancake windings. Unlike the LTS magnet, providing an air gap between the pancake windings increases the central magnetic field of a HTS magnet. Furthermore, the uniformity of the magnetic field near the center of the magnet increased because the pancake windings spread out in wider area. Effects of the air gap on the central magnetic field of an HTS magnet was described in this paper, Calculation of the critical current was carried out by using E-J relation of the HTS wire and the optimization technique was adopted to obtain the appropriate critical current which could maximize the central magnetic field. Pancake windings with BSCCO-2223 HTS wire were wound on glass epoxy bobbin. 6 double pancake windings with 200 turns were used to construct a HTS magnet. Characteristics of the HTS magnet including the central magnetic field and the uniformity of the magnetic field were measured and compared with the results of calculation.

• 한국광과학회:학술대회논문집
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• 한국광과학회 1999년도 학술대회지
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• pp.77-78
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• 1999

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2002년도 춘계연구발표회 논문개요집
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• pp.138-139
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• 2002

• Investigative Magnetic Resonance Imaging
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• 제20권3호
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• pp.196-199
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• 2016

Viagra has been prescribed worldwide to treat men with erectile dysfunction. Clinical trials have shown that Viagra may cause various kinds of adverse effects include some central nervous system (CNS) adverse effects. Although extremely rare, toxic encephalopathy also can be one of those effects. This report presents a case of encephalopathy caused by Viagra in correlation with its radiologic findings. Its pharmacologic mechanism and potential effects on the biochemistry of the CNS are reviewed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.36-41
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• 2001

The performance of an inductive position sensor is described by the accuracy and the dynamic characteristics of the sensor. Both of these performance indices are affected by magnetic hysteresis and eddy currents. In this paper, a model of an inductive sensor is presented. This model includes the effects of hysteresis and eddy currents. Computer simulation shows that the sensitivity of the sensor is greatly affected by hysteresis and eddy currents. Repeability error increases with hysteresis and eddy currents effects. Results also show that eddy currents influence more on the sensor performance than hysteresis does. To reduce the effects of hysteresis and eddy currents, the sensor should be made out of thin laminations with high resistivity.

• 한국의학물리학회지:의학물리
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• 제13권4호
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• pp.195-201
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• 2002

측방 산란이 상대적으로 많은 6 MeV 전자선에 대하여 세로 자기장에서 반음영의 변화를 몬테칼로 계산을 이용하여 연구하였다. 전자의 물질과의 상호작용 계산에서 외부 자기장의 효과를 반열하기 위하여 자기장에서 전자의 방향변화에 관한 알고리즘을 개발하여 EGS4 시스템에 삽입하였다. 완성된 코드를 이용하여 점선원 기하구조를 설정하고 SSD 100 cm에서 직경 5 cm인 전자선에 대하여 0-3 T의 세로 자기장이 걸려있는 팬텀속 1.5 cm, 2.0 cm, 2.4 cm 깊이에서의 빔 프로파일을 계산하였다. 자기장의 세기에 따른 반음영의 감소를 나타내기 위해 같은 질이에서의 기존 반음영의 폭과 자기장에 의한 반음영 폭의 감소 비로 반음영 감소율(PRR)을 정의하였다. 계산결과 팬텀속 1.5 cm, 2.0 cm, 2.4 cm 깊이에 대하여 자기장의 세기가 2 T인 경우에 PRR은 각각 27%, 36%, 36%로 나타났으며, 3 T인 경우에는 각각 46%, 50%, 50%로 나타났다 0.5 T와 1 T에서는 자기장의 효과가 매우 미약하였다. 이 결과는 6 MeV 전자선의 경우에 2 T 이상의 자기장을 세로방향으로 인가한는 경우에 측방산란된 전자들이 자기장에 의하여 편향되면서 반음영의 폭이 크게 줄어드는 것으로 해석할 수 있다. 결론적으로 전자선치료에서 세로 자기장을 병행하는 경우에 조사면 가장자리의 선량감소가 보상됨으로써 치료효과의 증대를 기대할 수 있다.