• 전기학회논문지
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• 제56권5호
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• pp.933-937
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• 2007

A point plate type nonthermal plasma reactor, with a grounded cylindrical third electrode which closely- encompasses the needle point, have been investigated with an emphasis on the role of the third electrode. It was found that the point plate airgap, with the grounded third electrode, had a switching characteristic on its I V characteristics for negative and positive discharges, which is very different from that of a conventional point plate airgap without a third electrode. The corona discharge and ozone generation characteristics of the plasma reactor with the grounded cylindrical third electrode, such as the corona onset voltage. the breakdown voltage. the corona current. and the amount of output ozone, were influenced significantly by the height of the third electrode. and these characteristics can be controlled by adjusting the height of the third electrode.

• The Korean Journal of Ceramics
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• 제5권3호
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• pp.245-249
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• 1999

A new type of nonthermal plasma reactor utilizing ferroelectric pellets is proposed to generate nonthermal plasma efficiently, which is used for simultaneous control of various pollutant gases. Electric charges stored on ferroelctric pellets by corona discharge between a corona tip and a mesh electrode provide partial electrical discharges among ferroelectric pellets. These partial electrical discharges can enhance partial discharges around the surface of ferroelectric pellets. This method utilizes wide reacting area of ferroelectric pellets and partial discharge. Positive and negative dc voltage are applied to the corona tip to generate partial discharges, and corona currents are estimated to investigate charge storage on ferroelectric pellets as function of time and charge relaxation time constants of ferroelectric pellects. As a result, charge relaxationtime, dielectric constants of ferroelectric pellets, polarity of applied voltage and applied time influence partial discharges among ferroelectric pellect.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.118-118
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• 2010

In this paper, we analyzed the frequency spectrum of radiated electromagnetic waves which is generated by corona discharges as a basic study to develop a on-line diagnostic technique for power facilities installed in a closed-switchboard. Five types of electrode system were arranged to simulate corona discharge. The experiment was carried out in an electromagnetic shielding room, and the measurement system consists of an Ultra Log Antenna and an EMI Test Receiver. These results showed that the frequency spectrum of corona discharges exists widely in ranges from 30 to 1,000 [MHz].

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.41-45
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• 2010

In this paper, we analyzed the frequency spectrum of radiated electromagnetic waves generated by series arc- and corona- discharges as a basic study to develop an online diagnostic technique for power facilities installed inside switchboards. To simulate corona and series arc discharges, an arc generator specified in UL1699 and a corona generator were fabricated. The experiment was carried out in an electromagnetic shielding room, and the measurement system consists of an Ultra Log Antenna and an EMI Test Receiver. The frequency spectrum exists in ranges from 30 to 500 [MHz] for series arc discharge and 30 [MHz] to 2 [GHz] depending on defects for corona discharge. The peak frequency of series arc discharge and corona were 40 [MHz], 80 [MHz] and 35 [MHz]~160 [MHz], respectively.

• 대한전기학회논문지
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• 제38권8호
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• pp.650-657
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• 1989

The conversion efficiency of an ozone generator can be significantly improved by modifying the discharge electrode of a helical strip line rod-to-cylinder type ozone generator to a pyramid-project-embossed rod, and by using a pulse corona discharge. Parametric studies have been carried out to obtain optimum values of peak pulse voltage, pulse forming capacitance, feeder cable and ozone generator capacitance, interelectrode spacing and corona tip density of ozone generator, and feed air flow rate and temperature. The generated ozone concentration was very dependent upon the value of pulse forming capacitance, feeder cable and ozone generator capacitance, and corona tip density. Maximum conversion efficiency was obtained with a pulse forming capacitance of about 500pF, 75pF matched feeder cable and ozone generator, and a corona tip density of 16mm. When operated at optimum values, ozone yield of 79, 99, 80 g/KWh for the different interelectrode type ozone generators tested were obtained, which are approximately 30% higher than that of an industrial ozone generator.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1510-1515
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• 2004

The effects of additive ions on the generation of metallic nanoparticles were evaluated using a corona induced supersonic nozzle. Applying the corona discharge to the nanoparticle generator, a tungsten needle and the supersonic nozzle are used as an anode electrode and a cathode electrode respectively. The corona ions act as nuclei for the silver vapor condensation. The ion density was controlled precisely as varying the applied voltage between electrode and nozzle. The mean diameter of the silver particle decreases as the ion density increases. However, the number concentration of the silver particle tended to increase with the ion density. The size distribution is more uniform as the ion density increases.

• 전기의세계
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• 제19권6호
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• pp.18-25
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• 1970

The object of this project is to manifest the mechanism of deterioration phenomena for dielectrics causing corona discharge and applies it for determine the standard corona detection technique. As the results, we observed that corona discharges may occur more strongly around cylindrical shape electrode in air than hemisphere shape electrode in vacuum, so that it depends on effects such as shape of the electrode, moisture, surface coditions, etc. According to observed the deterioration of dielectrics takes place in following stages. At first the attacked surface by an electron avalanche is uniformly eroded; then pits are formed; after that sharp channels are formed which lead to break-down as a treeing. The test are accelerated with higher frequencies by the cylindrical bar shape electrode in the pulse stright detection method more sensitive than Lissajous patterns. Lissajous patterns detection method is simple but usually insensitive and has disadvantage that the magnitude of the individual discharge is not measured.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2070-2076
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• 2015

Nano composite materials were multi-constituent combinations of nano dimensional phases with distinct differences in structure, chemistry and properties. Nano particles were less likely to create large stress concentrations and thereby can avoid the compromise of the material ductility while improve other mechanical properties. Corona discharge was an electrical discharge. The ionization of a fluid surrounding a conductor was electrically energized. This discharge would occur when the strength of the electric field around the conductor was high enough to form a conductive region, but not high enough to cause electrical breakdown or arcing to nearby objects. This paper shows all the studies done on the preparation of nano fillers. Special attention has given to the ACSR transmission line conductor, TiO₂ nano fillers and also to the evaluation of corona resistance on dielectric materials discussed in detail. The measurement of the dielectric properties of the nano fillers and the parameters influencing them were also discussed in the paper. Corona discharge test reveals that in 0%N ACSR sample corona loss was directly proportional to the applied line voltage. No significant change in corona loss between 0%N and 1%N. When TiO₂ nano filler concentration was increased up to 10%N fine decrement in corona loss was found when compared to base ACSR conductor, corona loss was decreased by 40.67% in 10%N ACSR sample. It was also found from the surface conditions test that inorganic TiO₂ nano filler increases the key parameters like tensile strength and erosion depth.

• Journal of Electrical Engineering and Technology
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• 제11권5호
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• pp.1348-1356
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• 2016

• 공업화학
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• 제27권6호
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• pp.627-632
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• 2016

PVDF-PVC 적층필름의 계면접착력을 향상시키기 위한 새로운 방법으로 PVDF 필름 표면에 유전체장벽 코로나 방전을 통한 EMA 단량체 커플링을 시도하였다. EMA 1% 분위기에서 코로나 표면처리한 PVDF 필름을 사용하여 제조한 PVDF-PVC 적층필름의 계면접착력은 코로나 처리하지 않은 PVDF에 비해 현저히 향상되었다. 코로나 방전처리에 의해 PVDF 필름 표면의 접촉각은 현저히 감소하였다. XPS 분석 결과, 코로나 처리에 의해 필름 표면의 탄소와 산소함량은 증가하는 반면 불소 함량은 감소하였다. XPS $C_{1s}$ 피크의 curve fitting 결과, 코로나 방전 처리에 의해 비극성 C-C 결합 탄소와 산소와 결합하는 탄소의 비율은 점차 증가한 반면, 불소와 결합하는 탄소의 비율은 크게 감소하는 경향을 나타내었다.