• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.175.1-175.1
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• 2016

In recent, tract infections such as atopic dermatitis, allergic rhinitis and a respiratory disease are increasing, giving rise to the atmospheric pollution, inflow of micro-size dust and side effect of humidifier disinfectant. In this context, the environment-friendly technology is required to eliminate airborne pathogens. We propose solution of the previous problems, making use of Radical Mist Generator (RMG). Existing technologies of air purification using a gas discharge produce harmful substances such as ozone, NOx, etc. However, the RMG uses a pure water as a plasma forming material. The RMG sprays the water mist, which contains reactive radicals to sterilize microorganisms. RMG is comprised of a power supply, plasma electrodes and a nozzle. In order to analyze the electrical characteristic and concentrations of reactive radicals, we employ an oscilloscope and a titration method. To test the sterilization effect of RMG, we used E.coli. We confirmed that E.coli was killed over 90%. Eventually, we expect that RMG can be promising tool for a purified system.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.140.1-140.1
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• 2015

Currently, As Plasma application is expanded to the industrial and medical industrial, Low temperature plasma characteristics became important. Especially in Medical industrial, Low temperature plasma directly adapted to human skin, so their plasma parameter is important. One of the plasma parameters is electron density, some kinds of method to measuring electron density are Thomson scattering spectroscopy and Millimeter-wave transmission measurement. But most methods is expensive to composed of experiment system. Heterodyne interferometer system is cheap and simple to setting up, So we tried to measuring electron density by Laser heterodyne interferometer. To measuring electron density at atmospheric pressure, we need to obtain the phase shift signal. And we use a heterodyne interferometer. Our guiding laser is Helium-Neon laser which generated 632 nm laser. We set up to chopper which can make a laser signal like a pulse. Chopper can make a 4 kHz chopping. We used Needle jet as Ne plasma sources. Interference pattern is changed by refractive index of electron density. As this refractive index change, phase shift was occurred. Electron density is changed from Townsend discharge's electron bombardment, so we observed phenomena and calculated phase shift. Finally, we measured electron density by refractive index and electron density relationship. The calculated electron density value is approximately 1015~1016 cm-3. And we studied electron density value with voltage.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.784-787
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• 2003

In this study, water jet etching of aqueous green tape was attempted for processing barrier rib of plasma display panel. This process combines 1) chemical etching between water and aqueous based binder in the tape and 2) mechanical erosion by water jet. Effects of etching parameters such as pressure, temperature and aqueous binder content on the morphology of barrier ribs formed were investigated. The results demonstrated a possibility of processing barrier ribs by water jet etching.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.775-777
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• 2003

Several methods are available for the fabrication of electrode pattern for the plasma display panel(PDP) including screen printing and photolithographic method. Piezo type ink-jet printing method is considered to the method of choice for electrode patterning in manufacturing of PDP. Both silver ink and absorbent layer paste formulation were developed for ink-jet printing of electrode pattern. The ink-jet printing of silver electrode with preformed absorbent layer was especially suitable for the patterning of address electrode for high resolution PDP.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.44.1-44.1
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• 2020

Hα jets of cool chromospheric plasma are protruding into the solar corona 10-100 Mm above the photosphere. The driving mechanisms of Hα jets have been widely studied for decades. However, the detailed process is still elusive. We observed shock signatures moving along a dark jet using 1.6 meter Goode Solar Telescope at Big Bear Solar Observatory. The first shock front of the jet shows sharp --- when it moves upward, while fuzzy and granulated when it moves downward. The jet itself extends upward when the second shock front of the jet reaches the top of the jet. We find abrupt EUV brightenings when the second shock front collides with the edge of the jet. The third front and the fouth front quasi-periodically. These phenomena might be the signs of the rebound shock waves triggered by p-mode wave leakages at the bottom of the jets. Our observation suggests that the jet can be triggered by the rebound shock waves generated by the p-mode waves leaked at the bottom of the jets.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.190.1-190.1
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• 2016

One of the most serious problems faced by billions of people today is the availability of fresh water. According to statistics, 15% of the world's total output of dye products is discharged into the environment as dye wastewater, which seriously pollutes groundwater resources. For the treatment of chemically and biologically contaminated water the advanced oxidation processes (AOPs) shows the promising action. The main advantage with AOPs is the ability to degrade the organic pollutants to $CO_2$ and $H_2O$. For this degradation process the AOPs generation of powerful and non-selective radicals that may oxidize majority of the organic pollutants present in the water body. To generate the various reactive chemical species such as radicals (${\bullet}OH$, ${\bullet}H$, ${\bullet}O$, ${\bullet}HO_2$) and molecular species ($H_2O_2$, $H_2$, $O_2$) in large amount in water, we have used the atmospheric pressure plasma. Among the reactive and non-reactive species, the hydroxyl radical (${\bullet}OH$) plays important role due to its higher oxidation potential (E0: 2.8 V). Therefore, in this work we have checked the degradation of various dyes such as methyl orange, methylene blue and congo red using different type of atmospheric pressure plasma sources (Indirect jet and direct jet). To check the degradation we have used the UV-visible spectroscopy, HPLC and LC-MS spectroscopy. Further, to estimate role of ${\bullet}OH$ on the degradation of dyes we have studied the molecular dynamic simulation.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.83-88
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• 2004

High voltage AC electric field has been applied to turbulent propane jets to investigate the effect of electric field on liftoff characteristics. Liftoff velocity and liftoff height have been measured by varying the applied voltage and frequency. Liftoff velocities were delayed and liftoff heights were reduced by applying AC, not by DC. The electric effect became disappeared with further increasing jet velocities, which shows that the effect can be explained by the balance between inertia force and electric force. The flame stabilization effect was intensified as either applied voltage or frequency increased. Plasma streamers were generated between the flame and the jet under high voltage conditions. Liftoff velocity in the absence of plasma can be well correlated by the function of voltage and frequency.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.326-326
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• 2011

최근 다양한 종류의 태양전지의 연구가 수행되고 있으며 그 중 박막형 태양전지 및 웨이퍼 실리콘 기반의 태양전지의 경우 태양전지의 효율 및 생산단가를 충족시키는 것에 연구의 목적이 집중되어 있다. 이러한 사항을 만족시키기 위하여 대면적 PECVD기반의 플라즈마 소스를 적용하려는 연구가 진행되고 있으며 결정질의 실리콘 박막 증착에 있어서 다중접합 태양전지 기준으로 효율 10% 내외를 유지하면서 결정질 기준 증착속도 0.5 nm/sec의 성과를 보이고 있다. 하지만 단위 가격 당 전력 생산 단가의 경쟁력을 확보하기 위하여 증착속도의 고속화에 대한 연구가 더욱 진행되어야 한다. 본 연구에서는 새로운 플라즈마 방전 개념으로서 Gas의 분사되는 Jet을 plasma에 통과시켜 증착속도의 향상을 도모하는 plasma 소스를 제시하였다. 새로운 방전 개념을 이용하여 다양한 공정조건인 압력(3~8 torr), Gas ratio([SiH4]/[H2]), RF power에서의 Plasma의 특성을 확인 하였으며 해당 조건에서의 박막 특성을 확인하여 비정질 기준 3 nm/sec, 결정질 기준 결정화도 약 70%의 조건에서 증착속도 2 nm/sec의 결과를 확인하였다. 또한 해당 조건에서의 효율 및 FF, $V_{oc}$, $I_{sc}$를 확인하여 태양전지로서의 적용가능성을 확인하였다. 마지막으로 해당소스의 대면적 적용가능성을 확인하기 위하여 대면적 plasma 개념의 모델중 하나인 In-line 개념의 plasma source로서의 적용 가능성을 제시하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.363-366
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• 2011

Mixing and combustion experiments with a vent slot mixer were performed in Mach 2 supersonic wind tunnel. Helium and hydrogen gases each were used for the mixing and the combustion experiment with a plasma jet (PJ) torch. The vent slot mixer holds plenty of fuel in the downstream mixing region, even though the fuel is transversely injected. In case of the combustion, the injected fuel is ignited by the PJ torch, and then unburned mixture is burned by shock-induced combustion downstream. Thermal choking in the combustor leads to shock trains in the isolator, causing the unstable combustion.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.104-105
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• 2001

Recently, plasma injection has been suggested as a means to enhance and control combustion rates of propellant materials. It is also of interest for applications in fields such as rocket propulsion, electrothermal-chemical (ETC) launchers, and hypersonic mass acceleration technology. In order to characterize the plasma fundamental measurements such as the plasma excitation temperature and electron number density are essential. (omitted)