• 전기학회논문지
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• 제61권5호
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• pp.717-720
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• 2012

Various types of dielectric-barrier-discharge (DBD) devices have been developed for diverse applications for the last decade. In this study, a flat non-thermal DBD micro plasma source under atmospheric pressure has been developed. The flat-panel type plasma is generated by bipolar pulse voltages, and driving gas is air. In this study, the plasma source was investigated with intensified charge coupled device (ICCD) images and Optical Emission Spectroscopy (OES). The micro discharges are generated on the crossed electrodes. For theoretical analysis, 2-dimensional fluid simulation was performed. The plasma source can be driven in air, and thus the operation cost is low and the range of application is wide.

• Applied Science and Convergence Technology
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• 제26권4호
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• pp.74-78
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• 2017

The discharge characteristics of the radio frequency (RF) surface dielectric barrier discharge have been simulated for the investigation of the ratio of the ion transit time to the RF period. From one-dimensional particle-in-cell (PIC) simulation for a planar dielectric barrier discharge (DBD), it was observed that the high-frequency driving voltage confines the ions in the plasma because of a shorter RF period than the ion transit time. For two-dimensional surface dielectric barrier discharges, a fluid simulation is performed to investigate the characteristics of RF discharges from 1 MHz to 40 MHz. The ratio of the peak density to the average density decreases with the increasing frequency, and the spatiotemporal discharge patterns change abruptly with the change in the ratio of ion transit time to the RF period.

• 한국재료학회지
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• 제25권2호
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• pp.100-106
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• 2015

Plasma properties of dielectric barrier discharges (DBDs) at atmospheric pressure were measured and characterized using optical emission spectroscopy. Optical emissions were measured from argon, nitrogen, or air discharges generated at 5-9 kV using 20 kHz power supply. Emissions from nitrogen molecules were markedly measured, irrespective of discharge gases. The intensity of emission peaks was increased with applied voltage and electrode gap. The short wavelength peaks (315.9 nm and 337.1 nm) measured at the middle of DBDs were significantly increased with applied voltage. The optical emission from DBDs decreased with the addition of oxygen gas, which was especially significant in argon discharge. Emission from oxygen molecules cannot be measured from air discharge and argon discharge with 4.8% oxygen. The emission intensity at 337.1 nm and 357.7 nm related with nitrogen molecule was sensitively changed with electrode types and discharge voltages. However, the pattern of argon emission spectrum was nearly the same, irrespective of electrode type, oxygen content, and discharge voltage.

• 한국표면공학회지
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• 제44권2호
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• pp.50-54
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• 2011

Hydrophobic a-C:F film was coated on polycarbonate film with $CF_4$, $C_2F_6$ and HFC ($C_2F_4H_2$) gas in helium discharge generated by 5~100 kHz AC power supply at atmospheric pressure and room temperature. The highest water contact angle of the a-C:F film formed with $He/C_2F_6$ mixed gas is $155^{\circ}$. X-ray photoelectron spectrum showed that there was 40% of C-$CF_3$ bond at the surface of the super hydrophobic film. The contact angle and deposition rate were decreased with increasing substrate temperature. The contact angle was generally increased with the surface roughness of the film. The contact angle was high when the surface microstructure of the film was fine and sharp at the similar roughness and chemical composition of the surface.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.152-155
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• 2003

Ashing of photoresist was investigated in dielectric barrier discharges in atmospheric pressure by changing applied voltage, frequency, flow rate. we analyzed the plasma by Optical Emission Spectroscopy(OES) to monitor the variation of active oxygen species. Another new peaks of oxygen radical is observed by addition of argon gas. This may explain the increase in ashing rate with argon addition. With the results of Optical Emission Spectroscopy(OES), we can find the optimized ashing conditions. MIS capacitor for monitoring charging damage by the plasma was also studied. The results suggest the dielectric barrier discharges(DBD) can be an efficient, alternative Plasma source for general surface processing.

• Applied Science and Convergence Technology
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• 제25권6호
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• pp.138-144
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• 2016

The discharge characteristics of pulse-driven coplanar micro barrier discharges for an ultraviolet (UV) light source using Ne-Xe mixture have been investigated using a two-dimensional fluid simulation at near-atmospheric pressure. The densities of electrons, the radiative excited states, the metastable excited states, and the power loss are investigated with the variations of gas pressure and the gap distance. With a fixed gap distance, the number of the radiative states $Xe^*(^3P_1)$ increases with the increasing driving voltage, but this number shows weak dependency on the gas when that pressure is over 400 Torr. However, the number of the radiative states increases with the increase of the gap distance at a fixed voltage, while the power loss decreases. Therefore, a long gap discharge has higher efficiency for UV generation than does a short gap discharge. A slight change in the electrode tilt angle enhances the number of radiative species 2 or 3 times with the same operation conditions. Therefore, the intensity and efficiency of the UV light source can be controlled independently by changing the gap distance and the electrode structure.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.528-528
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• 2012

Recently, atmospheric pressure plasmas attract lots of interests for the useful applications such as surface modification and bio-medical treatment. In this study, a particle-in-cell Monte Carlo collision (PIC-MCC) simulation was adopted to investigate the discharge characteristics of a planar micro dielectric barrier discharge (DBD) with a driving frequency from 13.56 MHz to 162.72 MHz and with a gap distance of 80 micrometers. The variation of frequency, in the change in the electron energy probability function (EEPF). Through the relation between the ion trajectories and the frequency, results in the change of EEPFs is achievable with the turning point of frequency mode. Therefore, it is possible to categorize the efficient operation range of DBDs for its applications by controlling the interactions between plasmas and neutral gas for the generation of preferable radicals.

• 한국표면공학회지
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• 제48권5호
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• pp.245-252
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• 2015

In recent years, the cleaning and activation technology of surfaces using atmospheric plasma as well as the deposition technology for coating using atmospheric plasma have been demonstrated conclusively and drawn increasing industrial attention. Especially, due to the simplicity, the technology using atmospheric plasma enhanced chemical vapor deposition has been widely studied from many researchers. The plasma source type commonly used as the stabilization of diffuse glow discharges for atmospheric pressure plasma enhanced chemical vapor deposition pressure is the dielectric barrier discharge. In this review paper, some kinds of modified dielectric barrier discharge type will be presented. And, the characteristics of silicon based compound such as SiOx and SiNx deposited using atmospheric plasma enhanced chemical vapor system will be discussed.

• Korean Chemical Engineering Research
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• 제57권3호
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• pp.432-437
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• 2019

유연전극 기반의 대기압 부유전극 유전체 장벽 방전 (floating electrode-dielectric barrier discharge, FE-DBD) 시스템을 개발하여 플라즈마 특성을 분석하였다. 유연한 파워전극(powered electrode)을 구성하는 유연유전체로 polytetrafluoroethylene (PTFE), polydiemethylsiloxane (PDMS), polyethylene terephthalate (PET)를 사용하여 플라즈마를 발생하였을 때 플라즈마의 광학적 세기와 전자온도는 파워전극에 인가하는 전압이 증가할수록 증가하였고, 전압이 일정할 때는 PTFE < PDMS < PET 순으로 증가하였다. 이는 유전체의 종류와 전압에 따른 축전용량의 변화로 설명할 수 있었고, 유연전극 기반의 대기압 FE-DBD 플라즈마의 특성은 유연한 파워전극을 구성하는 유전체와 파워전극에 인가되는 전압을 변화함으로써 조절될 수 있음을 의미한다. 유연전극 대기압 FE-DBD 시스템은 피부 곡면을 따라 플라즈마가 발생될 수 있으므로 플라즈마 메디신(plasma medicine)에 유용할 것으로 기대한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.494-494
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• 2013

Atmospheric pressure non-thermal plasma of the needle-typed interaction with aqueous solutions has received increasing attention for their biomedical applications [1]. In this context, surface discharges at bio-solutions were investigated experimentally. We have generated the non-thermal plasma jet bombarding the bio-solution surface by using an Ar gas flow and investigated the emission lines by OES (optical emission spectroscopy) [2]. Moreover, The non-thermal plasma interaction with bio-solutions has received increasing attention for their biomedical applications. So we researched, the OH radical density of various biological solutions in the surface by non-thermal plasma were investigated by Ar gases. The OH radical density of DI water; deionized water, DMEM Dulbecco's modified eagle medium, and PBS; 1x phosphate buffered saline by non-thermal plasma jet. It is noted that the OH radical density of DI water and DMEM are measured to be about $4.33{\times}1016cm-3$ and $2.18{\times}1016cm-3$, respectively, under Ar gas flow 250 sccm (standard cubic centimeter per minute) in this experiment. The OH radical density of buffer solution such as PBS has also been investigated and measured to be value of about $2.18{\times}1016cm-3$ by the ultraviolet optical absorption spectroscopy.