• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1999-2001
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• 2000

Impulse breakdown voltage characteristics of sulphur-hexafluoride/nitrogen ($SF_{6}-N_{2}$) mixtures were presented. The applied voltages were the positive and negative lightning impulse (1.2/44${\mu}s$) and oscillating impulse ($0.4{\mu}s$/2.08MHz) voltages. The predischarge current was observed to clarify the breakdown mechanism. The electrode system was consisted of plane to plane configuration with a needle-shaped protrusion whose length and diameter are 10mm and 1mm. The measurements were carried out at the gas pressure of mixtures up to 0.5MPa with nitrogen concentrations varying from 5 to 20%. The electrical breakdown in $SF_{6}-N_{2}$ mixtures develops with steplike pulses in leader mechanism. The minimum breakdown voltages for the negative lightning and oscillating impulse voltages were higher than those for the positive.

• 전기의세계
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• 제29권2호
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• pp.129-132
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• 1980

For large gas-insulated systems, the conductor utilized possess some degree of surface roughness which locally enhances the applied field at highpressure in $SF_{6}$. In order to investigate the effect of field enhancement on the breakdown field strength, the spheric protrusion was employed which gives a quantitative analysis on field enhancement. For further investigations on the breakdown level and polarity effect in $SF_{6}$, the repeated breakdown tests were performed with d.c. voltage at pressures up to about 4 bar. The experimental results show that the breakdown level does vary noticeably due to successive voltage applications and the breakdown field strength measured for a test gap with the cathode protrusion is markedly lower than that determined from the identical anode protrusion.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.258-260
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• 2004

산업 발전과 정보화 사회로 인한 전력 수요의 급증으로 안정된 전기에너지 공급을 위해 전력계통은 고전압 대용량화되고 있다. 따라서 전력계통 현장에서 많이 사용되고 있는 GIS에 결함이 발생하면 치명적인 사고를 유발할 수 있다. 본 논문은 모의 GIS내 도전성 금속이물질 존재 시 발생되는 부분방전 신호를 절연진단 방법 중 하나인 UHF법을 이용하여 부분방전 시 방사되는 Narrow Band 방사전자파를 측정하여 $SF_6$ 가스의 절연 특성을 연구하였다. 이러한 연구는 GIS 및 전력기기에 사용되는 $SF_6$ 가스의 절연 이상으로 인한 사고를 미연에 방지하기 위한 부분방전 탐지에 중요한 기초 자료가 될 것으로 사료된다.

• 조명전기설비학회논문지
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• 제24권7호
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• pp.41-46
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• 2010

With the improvement of industrial society, high quality electrical energy, simplification of operation and maintenance, and ensuring reliability are being required. Also we request an urgent change from $SF_6$ gas to an environment-friendly gas insulation material. In this paper, the experiments of breakdown characteristics by pressure and gap change of $N_2/O_2$ mixture gas through a GIS (Gas Insulated Switchgear) model were described. This paper reviews basic data of the surface discharge characteristics for Teflon resin in not only pure $N_2$, $N_2:O_2$ mixture gas as being focused on environmentally-friendly insulating gas, but also $SF_6$. Also, insulation characteristics by breakdown voltage and surface discharge voltage of $N_2:O_2$ mixture gas in the experimental chamber were studied.

• Ocean Science Journal
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• 제43권1호
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• pp.17-24
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• 2008

Over a period of 5 days between August 12 and 17, 2005, we performed a gas exchange experiment using the dual tracer method in a tidal coastal ocean located off the southern coast of Korea. The gas exchange rate was determined from temporal changes in the ratio of $^3He$ to $SF_6$ measured daily in the surface mixed layer. The measured gas exchange rate($k_{CO_2}$), normalized to a Schmidt number of 600 for $CO_2$ in fresh water at $20^{\circ}C$, was approximately $5.0\;cm\;h^{-1}$ at a mean wind speed of $3.9\;ms^{-1}$ during the study period. This value is significantly less than those obtained from floating chamber-based experiments performed previously in estuarine environments, but is similar in magnitude to values obtained using the dual tracer method in river and tidal coastal waters and values predicted on the basis of the relationship between the gas exchange rate and wind speed (Wanninkhof 1992), which is generally applicable to the open ocean. Our result is also consistent with the relationship of Raymond and Cole (2001), which was derived from experiments carried out in estuarine environments using $^{222}Rn$ and chlorofluorocarbons along with measurements undertaken in the Hudson River, Canada, using $SF_6$ and $^3He$. Our results indicate that tidal action in a microtidal region did not discernibly enhance the measured $k_{CO_2}$ value.

• 한국진공학회지
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• 제18권2호
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• pp.85-91
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• 2009

현재 플렉시블 폴리머를 이용한 MEMS (Microelectromechanical Systems) 기술이 빠르게 발전하고 있다. 그 중에서 Polycarbonate (PC), Poly Methyl Methacrylate (PMMA)와 같은 플렉시블 폴리머 재료는 광학적 특성이 우수하고 인체 친화적이며 미세 패턴 제조 공정이 용이하다는 등의 많은 장점을 가지고 있다. 본 연구는 반응성 이온 식각 기술을 이용하여 $O_2$, $SF_6$ 그리고 $CH_4$의 삼성분계 가스의 혼합 비율에 따른 PC와 PMMA의 건식 식각 결과 및 특성 평가에 관한 것이다. 준비한 각각의 기판에 포토리소그래피 방법으로 마스크를 형성하여 샘플을 만들었다. RF 척 파워를 100 W, 총 가스 유량을 10 sccm으로 고정시켜 플라즈마 식각 실험을 실시하였다. 그 결과에 의하면 전체적으로 PMMA의 식각율이 PC보다는 약 2배 정도 높았다. 그 결과는 PC는 PMMA 보다 상대적으로 높은 녹는점을 가지고 있다는 사실과 관계가 있다고 생각한다. 또한 $O_2/SF_6/CH_4$의 삼성분계 가스와 $SF_6/CH_4$, $O_2/SF_6$, $O_3/CH_4$로 나누었을 때 $O_2/SF_6$의 혼합 가스에서 PMMA와 PC의 식각 속도가 가장 높았다 (PC: 5 sccm $O_2$/5 sccm $SF_6$에서 약 350 nm/min, PMMA: 2.5 sccm $O_2$/7.5 sccm $SF_6$에서 약 570 nm/min). SEM을 활용하여 식각된 표면을 분석한 결과 PC는 PMMA보다 상대적으로 식각 표면이 더 매끈하였다. 또한 표면 거칠기 분석결과 PC의 표면 거칠기는 1.9$\sim$3.88 nm이었지만 PMMA의 표면 거칠기는 17.3$\sim$26.1 nm로 현저하게 높았음을 확인할 수 있었다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.529-534
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• 2008

Interzonal air movements are important to characterize overall ventilation performance of complicated multi-zone buildings. Tracer gas techniques are widely used to measure ventilation rates, ventilation effectiveness, and interzonal air movements. Depending on the number of gases used, they are divided into single and multi tracer gas methods. This paper deals with the comparison of the tracer gas methods in measuring air exchange rate between rooms. Experiments have been conducted in a simple two-room model with known airflow rates. In multi-gas procedure, the concentration decays of two tracer gases, i.e SF6 and R134a are measured after simultaneous injections in each room. The single tracer gas method is also applied by injecting SF6 gas with a time lag between two rooms. The data reduction procedures are developed to obtain the interzonal airflow rate using the matrix inversion, and various data manipulation methods are tested, such as data shift, interpolation, and smoothing. Uncertainty for each airflow rate is investigated depending on the parameters based on the setting values.

• 설비공학논문집
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• 제21권11호
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• pp.606-612
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• 2009

Interzonal air movements are important to characterize overall ventilation performance of complicated multi-zone buildings. Tracer gas techniques are widely used to measure ventilation rates, ventilation effectiveness, and interzonal air movements. Depending on the number of gases used, they are divided into single and multi tracer gas methods. This paper deals with the comparison of the tracer gas methods in measuring air exchange rate between rooms. Experiments have been conducted in a simple two-room model with known airflow rates. In multi-gas procedure, the concentration decays of two tracer gases, i.e SF6 and R134a are measured after simultaneous injections in each room. The single tracer gas method is also applied by injecting SF6 gas with a time lag between two rooms. The data reduction procedures are developed to obtain the interzonal airflow rate using the matrix inversion, and various data manipulation methods are tested, such as data shift, interpolation, and smoothing. Uncertainty for each airflow rate is investigated depending on the parameters based on the setting values.

• 한국재료학회지
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• 제10권6호
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• pp.450-455
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• 2000

실리콘 소자가 더욱 미세화되면서, 발생되는 power consumption, crosstalk와 interconnection delay 등을 감소시키기 위해 $SiO_2$ 대신에 저유전 상수막의 적용이 고려되어진다. 본 논문에서는, 저유전 상수 층간 절연막 재료로 유망한 폴리이미드의 식각 특성에 $O_2/SF_6$ 가스가 미치는 영향을 연구하였다. 폴리이미드의 식각률을 SF(sub)6 가스의 첨가에 따라 산소와 hydrocarbon 폴리머 간의 반응을 억제하는 비휘발성 물질은 fluorine 화합물의 형성에 의해 감소되었다. 반면에, 기판 전극의 전압 증가는 물리적인 충격을 통해 식각 공정을 증가시켰다. 또한 작은 량의 SF(sub)6 가스 첨가는 식각 topography에 바람직하였다. 폴리이미드 식각을 위한 $SiO_2$ hard mask 사용은 산소 플라즈마 식각 하에서 효과적이었다(선택비-30). 반면에 $O_2SF_6$ 가스 조성은 식각 선택비를 4로 저하시키게 되었다. 이러한 결과를 기초로, $1-2\mu\textrm{m}$ 선폭을 가진 PI 2610의 식각을 원활히 수행할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.178-179
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• 2006

In this paper the experiments of breakdown characteristics SF6 liquid ($LSF_6$) in model GIS(Gas Insulated Switchgear) were described. From the experiments results, The ability of $LSF_6$ insulation is higher than high-pressurized SF6 gas. The breakdown characteristics of $LSF_6$ were produced by bubble formed evaporation of $LSF_6$ and bubble caused by high electric emission. It is considered in this paper that the results are fundamental data for electric insulation design of superconductor and cryogenic equipments machinery which will be studied and developed in the future.