• Mass Spectrometry Letters
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• v.3 no.4
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• pp.108-111
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• 2012

An experimental study on the nascent product of the OH heterogeneous reaction with NaCl was performed under dry and wet conditions using a bead-filled flow tube system coupled to a high-pressure chemical ionization mass spectrometer. The ozone concentration in the flow tube for the atomic hydrogen removal was varied in order to control the conversion reaction of molecular chlorine into HCl for the identification of the nascent product. The mass spectrometric observation was that the $O_3$ introduction reduced the concentration HCl, while it increased the concentration of $Cl_2$ and ClO. Based on the experimental results, we suggest that the nascent product of the titled reaction is gaseous $Cl_2$, which is followed by fast conversion into HCl in presence of H. No significant difference in the concentration profile between under dry and wet (RH = 2%) conditions was observed.

• Korean Journal of Agricultural Science
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• v.45 no.1
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• pp.94-104
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• 2018

Nitrite is an essential additive for cured meat product. Plasma is ionized gas and reactive nitrogen species in plasma can be infused into meat batter and subsequently generate nitrites by reaction with water molecules after plasma treatment. However, the increase of nitrite in meat batter is limited with direct treatment of atmospheric pressure cold plasma because of the increase of meat batter temperature. Therefore, this study investigated the influence of indirect treatment of atmospheric pressure cold plasma on the physicochemical properties of meat batter. Meat batter was indirectly treated with plasma at 1.5 kW for 60 min. The pH of meat batter decreased while the temperature increased with plasma treatment time. The total aerobic bacterial count of meat batter was not affected by plasma treatment. The nitrite content of meat batter was increased to 377.68 mg/kg after 60 min of plasma treatment. The residual nitrite content of cooked meat batter also increased with plasma treatment time. The CIE $a^*$-value of cooked meat batter increased. As plasma treatment time increased, lipid oxidation tended to increase and protein oxidation significantly increased. According to these results, the indirect treatment of atmospheric pressure cold plasma can be used as a new curing method for replacing synthetic nitrite salts.

• Journal of Environmental Science International
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• v.10 no.6
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• pp.417-422
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• 2001

The vertical structure of atmosphere was observed In investigate the variation of surface ozone concentration by vertical downward mixing of residual ozone in the atmospheric boundary layer at the Busan coastal area. Airsonde and pilot balloon measurements were made at Gamcheondong and the Kimhae airport for April 26~27, 1996. The vertical potential of potential temperature showed a residual layer between 510m and 1800m from 2100LST April 26 to 0900LST April 27. The downward mixing of ozone in the residual layer of the atmospheric boundary layer was confirmed from vertical profile of mixing ratio near 600m in the morning. The thickness of the sea breeze layer was 900m at 1500LST April 26. Thereafter, it become to be lowered with time A low level jet was measured near 900m at 0300LST on April 27 from a pibal measurement. Early morning sharp increase of surface ozone concentration at the Busan coastal area was caused by vertical downward mixing of ozone concentration rather than by photochemical reaction In the atmospheric boundary layer.

• Polymer(Korea)
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• v.32 no.5
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• pp.433-439
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• 2008

An atmospheric plasma pre-treatment method was applied to polyurethane foam (density: 0.27) and rubber (butadiene rubber) to improve its contact angle and adhesion using atmospheric plate type reactor. In order to investigate the optimum reaction condition of plasma treatment, type of treatment gas (nitrogen, argon, oxygen, air), rate of gas flow ($30{\sim}100\;mL/min$), and treated time ($0{\sim}30\;s$) were examined in a plate plasma reactor. The result of the surface modification with respect to the treatment procedure was characterized by using SEM and ATR-FTIR. Due to a decrease of the contact angle of various materials, the greatest adhesion strength was achieved at optimum condition such as flow rate of 100 mL/min, reaction time of polyurethane foam 10 s and rubber 3 s for an atmosphere nitrogen gas. Consequently, the atmospheric plasma treatment reduced the wettability of the polyurethane foam and rubber also resulted in the improvement of the adhesion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.278-283
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• 2000

The activity of catalysts obtained by self-propagating high temperature synthesis in reaction of partial methane oxidation at atmospheric pressure was investigated. Basing on the compared results of X-ray analysis and gas chromatography analysis of reaction products, the dependence of compounds formation on the phase concentrations in the studied catalyst samples was found.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.4
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• pp.415-425
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• 2003

A single particle analysis, called low-Z electron probe X-ray microanalysis was applied to characterize the atmospheric aerosols collected during Asian Dust storm events in the year of 2000 and 2001. Most frequently encountered chemical species were the soil-originated species such as aluminosilicates, silicon dioxide, and calcium carbonate. Also various species such as carbon -rich, organics, sea salts, and some reacted calcium carbonate were identified. The observation of internally mixed particles oi calcium carbonate, calcium nitrate and/or calcium sulfate shows the occurrence of the heterogeneous reaction between Asian Dust particles and NO$_{x}$ and/or SO$_{x}$ species in the atmosphere.ere.

• Mass Spectrometry Letters
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• v.8 no.1
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• pp.1-7
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• 2017

Studies performed on heterogeneous reactions of hydroxyl radicals (OH) in aerosol materials of tropospheric interest are presented, focusing on the chemical ionization mass spectrometric approach. Kinetic investigations of these reactions reduced deviation in the estimation of OH concentration in the troposphere by atmospheric modeling from field measurements. Recently, OH uptake was investigated under wet conditions to acquire kinetic information under more realistic conditions representative of the troposphere. The information on the mechanism and kinetics of OH uptake by tropospheric aerosol materials will contribute to the updating of atmospheric models, allowing a better understanding of the troposphere.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.2
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• pp.161-174
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• 2004

Aerosol formation and growth by water vapor reactions were investigated in a 2.5 -㎥ indoor smog chamber filled with the unfiltered ambient air. The relative humidity of test ambient air was elevated at 59～64% or 84～88% by adding water vapor. The aerosol number size distribution and the concentrations of $O_3$, NO, NO$_2$, and SO$_2$ were measured during the experiments. The $O_3$ and NO$_2$ gases were well reacted with the water vapor at high relative humidity of 84～88%, and the reaction rates of these gases seemed to be decreased at low relative humidity of 59～64%. The formation and condensational growth phenomena of ambient aerosols by water vapor reactions were observed in a Teflon bag, depending strongly on the initial particle size distribution. The water vapor reactions might be affected by the contents of oxidants produced by photochemical reactions under sunlight.

• Asian Journal of Atmospheric Environment
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• v.5 no.3
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• pp.181-188
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• 2011

Photocatalysis is a photochemical catalytic reaction which is a highly promising tool for the environmental cleanup process. It is very effective in treatment of environmental pollutants by its unique redox property. It has wide applications in the treatment of atmospheric pollutants (e.g., nitrogen dioxide, trichloroethylene, volatile organics, hydrogen sulfide, benzene, etc) through oxidative removal and by disinfection (aeromicro flora). In this research, the fundamental aspects of photocatalysis are described with respect to the composition of catalysts, experimental conditions (e.g., temperature, duration, etc), and interfering factors (e.g., catalyst deactivation).

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.5
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• pp.519-524
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• 1998

Formaldehyde is known to have adverse health effects, and is also found to be a product of atmospheric. photochemical reaction%. Several methods have been employed for the measurement of formaldehyde. Among them, two common methods are comparatively evaluated in this study, i.e. the chromotropic acid method and the HPLC method coupled with 2,4- dinitrophenylhydrazine (DNPH) derivatization of carbonyl compounds. Method evaluation and validation were performed with respect to repeatability, linearity, collection efficiency, and recovery efficiency. Comparison of formaldehyde concentrations measured simultaneously in the field using the two (n=20) and 35.8%, respectively. Overall, the measured levels by chromotropic acid method appeared to ice significantly higher than those by DNPH-HPLC method, indicating a positive interference due to the other aldehydes collected together with formaldehyde.