• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.369-370
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• 2008

This paper describes the electric field distribution of high voltage polymer bushing with inner field shaper designs. The field control can be achieved by means of the designs of such internal field shaper. But high electric stress occurred between field shaper and central conductor by the closely space. In accordance, the floating and ring shield designs was importance for electric stress grading at critical parts of the bushing. The bushing has a central conductor, and internal ring shield or floating shield, gaps are formed between field shaper and ring shield. Accordance equipotential lines extend through gaps. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing.

• 한국전기전자재료학회논문지
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• 제22권5호
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• pp.436-442
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• 2009

This paper describes a study on the design of compact polymer bushing with inner control shield. In the bushing, a high electric stress occurred between field shaper and central conductor by the closely space. Also coaxial cylindrical shield has a great height along the axis to control an electric field. Consequently, all the potentials are raised axially along the field shaper and electric stress is concentrated on a part of the surface of the FRP tube near the upper end of the field shaper. In accordance, the field control can be achieved by means of the designs of such inner control shields. The floating and ring shield designs was decreased electric field concentration at critical parts of the bushing. The shield gaps is formed between field shaper and ring shield. Accordance equipotential lines extend through gaps. As a result, the resulting electrical stress are thus reduced in the range $17{\sim}23%$ in the bushing with floating and ring shield designs. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing. The optimized design uses internal elements for electric stress grading at critical parts of the bushing.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.234-234
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• 2009

This paper illustrates the use of electric field computation to optimize the design of high voltage composite bushing. In the bushing, a high electric stress occurred between field shaper and central conductor by the closely space. Also coaxial cylindrical shield has a great height along the axis to control an electric field. Consequently, all the potentials are raised axially along the field shaper and electric stress is concentrated on a part of the surface of the FRP tube near the upper end of the field shaper. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing. The optimized design uses internal elements for electric stress grading at critical parts of the bushing.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 춘계학술대회 논문집
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• pp.35-35
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• 2010

This paper illustrates the use of electric field computation to optimize the design of high voltage composite bushing. In the bushing, a high electric stress occurred between field shaper and central conductor by the closely space. Also coaxial cylindrical shield has a great height along the axis to control an electric field. Consequently, all the potentials are raised axially along the field shaper and electric stress is concentrated on a part of the surface of the FRP tube near the upper end of the field shaper. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing. The optimized design uses internal elements for electric stress grading at critical parts of the bushing.

• 한국항행학회논문지
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• 제10권1호
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• pp.70-78
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• 2006

본 논문은 RFC2963에서 제안된 single rate Rate adaptive Shaper (srRAS)를 설계한 것이다. srRAS는 RFC2693에서 제안된 하향의 single rate Three Color Marker (srTCM)과 함께 사용된 쉐이퍼이다. 그것은 가변 속도로 출력되는 tail-drop FIFO (First Input First Out) 큐이다. srTCM은 srRAS로부터의 IP 패킷 스트림을 측정한 후 그 패킷을 green, yellow, 또는 red로 마킹해 준다. 이 쉐이퍼는 AF PHB (Per Hop Behavior)를 제공하는 DS (Differentiated Service) 네트워크의 입력에서 사용되도록 제안되었다. 그리고 srRAS는 srTCM의 상향 트래픽의 버스트성을 줄여줄 수 있다. 본 논문은 srRAS의 알고리즘, 구조, 그리고 FPGA 및 관련 기술을 통하여 구현할 수 있는 방안을 언급하였다.

• 한국정밀공학회지
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• 제7권2호
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• pp.14-27
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• 1990

Electromagnetic Pulse Forming is the one of the high velocity forming method. When the electric energy which is charged in the capacitor bank is suddenly discharged into the electromagnetic coil, the high magnetic field occurs at the airgap between the electromagnetic coil and workpiece. Thus we can obtain the high electromagnetic pressure, which is proportional to the square of magnetic flux density. This is the basic principle of the electromagnetic pulse forming. In this paper, the equivalent L-R-C circuit is derived by computing the magnetic field and its loss of the total system. Thus, the values of the magnetic flux density and pressure can be obtained from the equation of this circuit. As a result, the computed and measured values of the maximum magnetic flux density and pressure are compared and the characteristics of the tapered field shaper are further discussed as follows; 1) The strength of magnetic flux density and pressure can be controlled by the charged energy and the size of the airgap between the inner field shaper and the workpiece. 2) During the design of the tapered field shaper, the penetration of the magnetic flux through the sharp edge should be considered.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.489-490
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• 2008

This paper describes the analysis of electric field distribution of high voltage polymeric bushing with structure. The high voltage bushing consists of FRP tube and housing made of LSR. The field control can be achieved by means of the design of such internal field shaper and top corona ring as grading electrodes. In accordance, the optimized design uses both internal and external elements for electric stress grading at critical parts of the bushing. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymeric bushing.

• 한국콘텐츠학회논문지
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• 제8권11호
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• pp.182-188
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• 2008

최근 방사선치료의 중추적 역할을 담당하고 있는 다엽콜리메이터는 사용의 편리성 때문에 기존의 납합 금 차폐물을 급속도로 대체하고 있다. 그러나 다엽콜리메이터는 엽간 누설선량이나 디지털 신호를 입출력 알고리즘에 따른 오류가 발생할 수 있다. 저자는 미국 Varian사에서 제공하는 다엽콜리메이터의 입력 방법에 따른 차이를 모의치료장치 프로그램(XimaVision)값을 기준으로 전자펜 정보 전송장치(MLC shaper)와 디지털 변환장치(film scanner)에서의 오차와 유효 조사야를 여러 형태의 차폐윤곽으로 비교하였다. 기준 값과 비교하여 기본적인 차폐 윤곽(test1-5)에서 전자펜 전송방식은 $0{\sim}0.29cm$, $0.23{\sim}3.59cm^2$, 디지털 변환장치 방식은 $0{\sim}0.20cm$, $0.72{\sim2.59cm^2$ 차이를 보였다. 임상에서 적용되는 차폐 윤곽에서 전자펜 전송방식은 $0{\sim}0.54cm$, $0.04{\sim}1.68cm^2$, 디지털 변환장치 방식은 $0{\sim}0.78cm$, $0.24{\sim}3.89cm^2$ 차이를 보였고, 대부분 선속 중심선에서 멀어질수록 조사야가 클수록 오차범위가 증가함을 알 수 있었다. 다엽콜리메이터의 임상적용을 위한 다양한 정보 입력과정에서 기준점으로부터 수 mm 이내에서 오차가 잇었다. 그리고 유효 조사야는 실제 면적에 대하여 수 $cm^2$이내에서 오차가 발생하여 기계적 선량(Monitor Unit)이나 조사야 내 선량변화에 관여하지 않았다. 그러나 임계장기를 차폐 할 경우 장기의 움직임으로 표적용적의 일부가 포함되지 않을 수 있기 때문에 문제의 여지가 있다. 그러므로 오류를 최소화하기 위한 다엽콜리메이터의 입력과정에 세심한 주의를 기울여야 한다.

• 공학논문집
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• 제7권1호
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• pp.99-103
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• 2005

The ferrimagnetic resonance technique, with the inclusion of shaper anisotropy effects, was used to obtain information about the early stages in the precipitation of magnesium ferrite from iron-doped magnesia. The very small magnesioferrite particles were produced by precipitation method from solid solution of iron ion in single crystal magnesia. The temperature dependence of the resonance anisotropy field for a coherent assembly of hyperfine magnesium ferrite precipitates was investigated in the range 100~400K. The results are interpreted in terms of the shape anisotropy of the precipitates.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.121-122
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• 2007

본 연구는 유한 길이를 갖는 솔레노이드 내에 원통형 도체가 존재하는 경우, 코일에 펄스 전압을 인가했을 때 정적, 동적 특성을 고찰하였다. 또한 솔레노이드 내에 자속을 한 부분으로 집중시켜주는 B-field shaper를 삽입하여 같은 방법으로 펄스 전류 인가시의 정적, 동적 특성을 고찰하였다. 원통형 도체의 재질로는 Al, Cu, Fe 계열을 사용하였으며, 인가 전압은 고압용 콘덴서를 충전하여 수백 micro sec 단위의 짧은 시간에 통전하였다. 본 논문에서는 유한 길이 솔레노이드는 설계 기본 방법을 제시하였고, 설계된 시작품에 대한 동적특성 해석은 유한요소법을 이용하여 검증하였다. 해석결과로는 현상에 따른 솔레노이드 내의 원통 도체에 작용하는 자기력 분포, 인덕턴스 등 설계 변수에 대한 자기력 특성 값을 제시하였다.