• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.932-938
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• 2010

This paper proposed the effective treatment method for organic substances using the barrier discharge plasma process and catalytic chemical reaction followed from ozone decomposition. The decomposition by the plasma process of organic substances such as trichloroethylene, methyl alcohol, acetone, and dichloromethane carried out, and ozone is generated effectively at the same time. By passing through catalysts, ozone easily decomposed and further decomposed organic substances. And, 2-dimensional distribution of ozone using the optical measurement method is performed to identify the catalytic surface chemical reaction. In addition, CO is easily oxidized into $CO_2$ by this chemical reaction, which might be induced oxygen atom radicals formed at the surface of catalyst from ozone decomposition.

• Journal of Industrial Technology
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• v.25 no.A
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• pp.141-149
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• 2005

We investigated numerically the evolutions of several chemical species which are important for film growth and particle generation in the pulsed $SiH_4$ plasmas. During the plasma-on, the $SiH_x$ concentration increases with time mainly by the generation reaction from $SiH_4$, but, during the plasma-off, decreases because of the hydrogen adsorption reaction. During the plasma-on, the concentrations of negative ions increase with time by the polymerization reactions of negative ions and those become almost zero in the sheath regions because of the electrostatic repulsion. During the plasma-off, the concentrations of negative ions decrease with time by the neutralization reactions with positive ions and some negative ions can diffuse toward the sheath regions because there is no electric field inside the reactor. The polymerized negative ions of higher mass can be reduced successfully by using the pulsed plasma process.

• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.483-488
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• 2006

Etching process of PMMA (Polymethyl Methacrylate) on glass surface was investigated by dry etching technique using remote plasma. To determine the etching characteristics, the remote plasma etching was conducted for various process parameters such as plasma power, reaction gas and distance from plasma generation. As the distance from the plasma generation was increased, the etch rate of PMMA was linearly decreased by radical density in plasma. PMMA has removed by reactive radicals in the plasma. The etch rate increased with plasma power because of more reactive radicals. The etch rate and surface roughness of PMMA increased with $O_2$ concentration in the etchant.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1689-1692
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• 2013

Food is a common source of chromium (Cr) exposure. However, it is difficult to analyze Cr in complex food matrices by using inductively coupled plasma mass spectrometry (ICP-MS) because the major isotope, $^{52}Cr$, is masked by interference generated by the sample matrix and the plasma gas. Among the systems available to minimize interference, the recently developed collision-reaction interface (CRI) has a different structure relative to that of other systems (e.g., collision cell technology, octopole reaction system, and dynamic reaction cell) that were designed as a chamber between the skimmer cone and quadrupole. The CRI system introduces collision or reaction gas directly into the plasma region through a modified hole of skimmer cone. We evaluated the use of an CRI ICP-MS system to minimize polyatomic interference of $^{52}Cr$ and $^{53}Cr$ in various foodstuffs. The $^{52}Cr$ concentrations measured in the standard mode were 2-3 times higher than the certified values. This analytical method based on an ICP-MS system equipped with a CRI of helium gas was effective for Cr analysis in complex food matrices.

• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.497-502
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• 2014

The conversion reaction of methane and carbon dioxide at an atmospheric pressure plasma reactor filled with Ni-$Al_2O_3$ and Ni-$MgAl_2O_4$ catalyst was performed. Effects of various process parameters such as the applied electric power, reaction gas flow rate, reactor temperature, mixing ratio of reactants and the presence of the catalyst on the reaction between methane and carbon dioxide were analyzed. From the analysis of the contribution of the catalyst in the reaction step, even if the temperature raised to $400^{\circ}C$, there was no spontaneous catalytic conversion of methane and carbon dioxide without plasma discharges. When the catalysts for the conversion of methane and carbon dioxide would be adopted to the plasma reactor, the careful selection of suitable catalysts and process parameters should be essential.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.96-99
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• 2004

Silica fillers were coated by plasma polymer coatings of 1,3-diaminopropane, allylamine, pyrrole, 1,2-epoxy-5-hexene, allyl mercaptan and allyl alcohol using RF plasma (13.56 MHz). The coated fillers were then mixed with biphenyl epoxy, phenol novolac (curing agent) and/or triphenylphosphine (catalyst), and subjected to DSC analyses in order to elucidate the chemical reaction between functional moieties in the plasma polymer coatings and the epoxy resin. Only the samples with 1,3-diaminopropane and allylamine plasma polymer coated silica fillers showed heat of reaction peaks when they were mixed with biphenyl epoxy resin only, while these samples as well as the samples with 1,3-diaminopropane, allylamine and pyrrole plasma polymer coated silica fillers exhibited heat of reaction peaks when mixed with both biphenyl epoxy and phenol novolac (curing agent).

• Nuclear Engineering and Technology
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• v.44 no.1
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• pp.21-32
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• 2012

Fluorinated compounds mainly used in the semiconductor industry are potent greenhouse gases. Recently, thermal plasma gas scrubbers have been gradually replacing conventional burn-wet type gas scrubbers which are based on the combustion of fossil fuels because high conversion efficiency and control of byproduct generation are achievable in chemically reactive high temperature thermal plasma. Chemical equilibrium composition at high temperature and numerical analysis on a complex thermal flow in the thermal plasma decomposition system are used to predict the process of thermal decomposition of fluorinated gas. In order to increase economic feasibility of the thermal plasma decomposition process, increase of thermal efficiency of the plasma torch and enhancement of gas mixing between the thermal plasma jet and waste gas are discussed. In addition, noble thermal plasma systems to be applied in the thermal plasma gas treatment are introduced in the present paper.

• Polymer(Korea)
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• v.36 no.3
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• pp.302-308
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• 2012

The objective of this study is to investigate optimum reaction conditions for the grafting of poly($N$-vinyl- 2-pyrrolidone) (PVP) onto the surface of plasma-treated polypropylene film. The plasma treatment conditions were fixed as 200 W rf power, 6 LPM Ar flow rate, 30 sec treatment time, and 5 min exposure time after treatment. For graft copolymerization, we investigated the change of grafting degree with respect to reaction time, reaction temperature and $N$-vinyl-2-pyrrolidone concentration. Maximum grafting degree was obtained at the conditions of 6 h reaction time, $90^{\circ}C$ reaction temperature, and 40% $N$-vinyl-2-pyrrolidone concentration. The introduction of PVP was confirmed by ATR-FTIR, XPS, and SEM analysis.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.536-541
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• 2009

Plasma-polymerized acrylic acid films were deposited on Si wafer and KBr pellet by remote plasma-enhanced chemical vapor deposition (PECVD). Effects of plasma power, reaction pressure, indirect plasma method on the growth rate, chemical structure, and chemical bonding state of the films were investigated. Chemical structure and chemical state of the films were characterized by Fourier transformed infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis and curve fitting technique. Growth rate of the film increased to a saturation value with plasma power of 100 W, but showed the maximum with reaction pressure at 300 mtorr. Whenever W/FM factor (applied energy per gas molecule) increased by increasing plasma power or lowering pressure, the fragmentation of acrylic acid molecules was promoted. From the XPS curve fitting analyses, we found that the intensity of carboxyl COO bonding peak decreased with W/FM factor, and the tendency of intensity change of carboxylic COO peak was contrary to those of ether C-O and carbonyl C=O peaks.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.452-458
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• 2022

Three types of gas-liquid hybrid horizontal, vertical and needle-to-cylinder plasma reactors were fabricated. Through these reactors, a high-efficiency, eco-friendly cleaning concept that generates reactive active species generated in atmospheric plasma discharge and gas-liquid activation reaction of cleaning components through the potential difference within the electrode was presented. As a result of comparing the efficiency for cleaning performance, the needle-to-cylinder type reactor had the best characteristics. Through this study, it was confirmed that the gas-liquid hybrid atmospheric pressure plasma reactor has the potential to be applied to ultra-precision cleaning processes such as semiconductor processes.