• 센서학회지
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• 제4권1호
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• pp.15-20
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• 1995

본 논문은 시변전장을 측정할 수 있는 평판형 센서에 대하여 기술하였다. 광대역의 전장측정계를 구현하기 한 평판형 센서가 제안되었다. 측정계의 이론적인 원리와 설계방법에 대하여 제시하였으며, 교정실험 및 적용실험을 수행하였다. 교정실험을 통하여 전장측정계의 주파수대역과 감도는 $160\;[Hz]\;{\sim}\;25\;[MHz]$, 1.2 [mV/V/m] 이었다. 적용실험으로 고전압 실험실에서 임펄스전압과 진동성 과도전압에 의해 발생되는 전장을 제안된 측정장치로 측정하였으며, 측정결과는 우수하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2003년도 제24회 학술발표회 초록집
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• pp.35-35
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• 2003

• 대한기계학회논문집B
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• 제34권11호
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• pp.1015-1025
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• 2010

본 연구는 교류전기장이 인가된 전선에서의 화염전파특성에 전기장이 미치는 영향에 대한 실험적 연구이다. 폴리에틸렌으로 피복된 전선에서 인가된 교류전압과 주파수에 따라 화염전파율을 도출하였다. 그리고 화염전파는 선형적 화염 전파와 비선형적으로 가속된 화염 전파로 구분되어졌다. 이것은 전선에 인가된 교류전기장에 따라 형성된 전기장 세기의 축방향 분포가 원인이 된다. 그리고 기울어진 전선화염의 화염전파율이 상대적으로 높게 나타났다. 이러한 현상은 온도균형메커니즘으로 설명이 가능하다.

• Journal of electromagnetic engineering and science
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• 제6권2호
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• pp.130-134
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• 2006

This paper presents the reduction characteristics of penetrated electromagnetic fields through a narrow slot in a planar conducting screen of infinite extent. When a plane wave is excited to the narrow slot, the aperture electric field is controlled by the parallel wire or parallel plate connected on the slot. The magnitude of penetrated electromagnetic fields through a narrow slot is controlled by electric field distributions on the slot. An integral equation for the aperture electric field on narrow slots is derived and solved by applying Galerkin's method of moments. The results show that the magnitude of the penetrated electromagnetic field can be effectively reduced by installing the parallel wire or parallel plate on the slot.

• Journal of Microbiology and Biotechnology
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• 제21권6호
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• pp.646-651
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• 2011

Cultures of Saccharomyces cerevisiae were treated with pulsed electric fields to improve accumulation of zinc in the biomass. Under optimized conditions, that is, on 15 min exposure of the 20 h grown culture to PEFs of 1500 V and 10 ${\mu}s$ pulse width, accumulation of zinc in the yeast biomass reached a maximum of 15.57 mg/g d.m. Under optimum zinc concentration (100 ${\mu}g$/ml nutrient medium), its accumulation in the cells was higher by 63% in comparison with the control (without PEFs). That accumulation significantly correlated against zinc concentration in the medium. Neither multiple exposure of the cultures to PEFs nor intermittent supplementation of the cultures with zinc increased the zinc accumulation. The intermittent supplementation of the cultures with zinc and multiple exposures on PEFs could even reduce the accumulation efficiency, respectively, by 57% and 47%.

• 한국광학회:학술대회논문집
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• 한국광학회 1990년도 제5회 파동 및 레이저 학술발표회 5th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.64-68
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• 1990

Boundary element method using linear basis function is applied to obtain fields scattered from a 3-D dielectric sphere. Electric field integral equation is used on the surfaces of the dielectric material where its surface is discretized into trilateral cells. For plane wave incidence, scattered fields by a dielectric sphere is calculated and compared with its analytic solution. The total electric fields are calculated on the great circle of the sphere boundary as well as the outside of the sphere in the plane of the wave vector and the polarization vector of the incident electric field.

• 한국안전학회지
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• 제8권3호
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• pp.34-43
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• 1993

This paper presents a study on the characteristics and safety criteria for human body in ELF (Extremely Low Frequency : 50-60Hz) electric and magnetic fields. Many researches for ELF electric and magnetic fields, which are developed in the past, are studied and analyzed In this paper. In order to estabilish the safety criteria for human body in the field, the field intensity, induced current and voltage are calculated by the electrostatic field approach which is far simpler than the electromagnetic field one based on Maxwell equation. The method is applied to the 345 KV transmission line system In operation and 765 KV system under consideration. According to the results, the maximum value of field intensity, 6.8627KV/m, is evaluated at the location which is 14m away from transmission line. As the safety criteria value by the abroad researches asserting that the human can detect the Induced current in 6KV/m and above, 5KV/m and 7KV/m are recommended at residence area and nonresidence area, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2158-2160
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• 1999

In order to obtain the detailed informations about the lightning electromagnetic fields, the electric and magnetic fields radiated by lightning return strokes were observed with the electric field sensor of hemi-sphere type and the magnetic field sensor of loop type and their physical characteristics were statistically analyzed. The multiple stroke occurrence numbers was 2.6. In multiple lightning strokes the amplitude of peak and the time interval between the subsequent strokes were decreased as the number of the subsequent strokes increases.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.207-212
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• 2001

Electro-Rheological(ER) fluid are suspensions which show an abrupt increase in rheological properties under electric fields. ER effects arise from electrostatic forces between the starch particles dispersed in the electrically insulating silicone oil, induced when an electric field is applied. Yield stress of the fluids were measured on the couette cell type rheometer as a function of electric fields. This paper presents performance analyses of four types of the two parallel-plate. Which have different electrode length and width but same electrode area. On the basis of the pressure drop and flow rate analysis. Four types of the two parallel-plate are designed and manufactured. Using ER fluid, it is possible to directly interface between electric signals and fluid power without moving parts.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2000년도 추계 학술대회논문집
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• pp.72-77
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• 2000

This paper presents the results of the application of a computational fluid dynamics algorithm for the simulation of plasma flows of arc-heated jet. The underlying physical model is based on the axisymmetric form of the conservation equations that are coupled with an arc model including Ohm heating, electromagnetic forces. The arc model given as a source term in fluid dynamic equations is determined by a solution of electric potential field governed by an elliptic partial differential equation. The governing equation of electric field is loosely coupled with fluid dynamic equations by an electric conductivity that is a function of state variables. However, the electric fields and flow fields cannot be solved In fully coupled manner, but should be solved iteratively due to the different characteristics of governing equations. With this solution approach, several applications of arc flow analysis will be presented including Arc Thruster and Circuit Breaker.