• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.58-61
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• 2005

Environmental polluting materials from road surface drainage are a significant nonpoint source influenced to the eutrophication of lake and ecosystems with a transport development in recent years. To elucidate the discharge characteristics, the changing patterns in concentrations of polluting materials such as suspended solid (SS), chemical oxygen demand (COD), nitrogenous and phosphorus nutrients in drainage waters, were investigated during rainfall. Load variation of COD concentration in drainage water samples was closely related to that of SS concentration. This indicates that SS contained a greater part of organic matter. A quite difference between the past pavement and the new well-drainage pavement system was observed in the concentrations of SS and COD in drainage waters. Appreciable concentrations of nitrite and nitrate were determined in drainage waters. The present results indicate that the drainage water from road surfaces is a significant nonpoint source, and that the well-drainage pavement system introduced to skid prevention has an effect on the decreases of pollutants.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.2
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• pp.124-138
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• 2017

Physico-chemical measurement of non-refractory submicron particles($NR-PM_1$) was conducted in Baengnyeong Island, Korea using Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) from 2012 to 2014. Organics and ammoniated sulfate were dominant species in $NR-PM_1$. The organics was found to have similar fractions(approximate 40%) of $NR-PM_1$ during the summer and winter, while the sulfate fractions of $NR-PM_1$ were calculated to be approximately 47% and 31% for the summer and winter, respectively, suggesting the possibility that particles provide non-acidic surfaces for condensation of nitric acid in the winter. The nitrate fractions of approximate 4% and 20% of $NR-PM_1$ were observed in August (summer) and November (winter), respectively, resulting that the relatively low concentration of sulfate in $NR-PM_1$ provided a non-acidic surface for nitric acid condensation and formation of particulate ammoniated nitrate is favored thermodynamically in winter. The new particle formation (NPF) event and particle growth rate were analyzed for each month in 2014 using Scanning Mobility Particle Sizer(SMPS). The Percent of NPF events was the highest in winter, but NPF event was not observed during summer due to relatively high temperature and frequent rainfall. The average particle growth rate was 3.5 nm/h and the highest particle growth rate was 5.5 nm/h in May. We observed the long-range transport of the anthropogenic sulfate from the East Asia during the intensive monitoring period of November between Qingdao and Baengnyeong Island in 2013. The relatively high concentrations of m/z 60 measured in HR-ToF-AMS was observed in May and June at Baengnyeong Island, suggesting the possibility of the influence of biomass burning from the East Asia to the Korean Peninsula.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.77-90
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• 2022

Despite the decreasing trend of anthropogenic emissions in East Asia in recent years, haze days still frequently occur in spring. Atmospheric blocking, which occurs frequently in the northeastern Pacific, leads to persistent changes in large-scale circulation and blocks westerly flow in the East Asian region. During March 2019, frequent warm and stagnant synoptic meteorological conditions over East Asia were accompanied 6-7 days later by the Alaskan atmospheric blocking. The Alaskan atmospheric blocking over the period of March 18-24, 2019 led to high particulate matter (PM₁₀) severe haze days exceeding a daily average of 50 ㎍ m^-3 over the period of March 25-28, 2019 in South Korea. Although the high-PM₁₀ severe haze days were caused by warm and stagnant meteorological conditions, the regional contribution of anthropogenic emissions in eastern China was calculated to be 30-40% using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). The major regional contributions of PM₁₀ aerosols in the period of high-PM₁₀ severe haze days were as follows: nitrates, 20-25%; sulphates, 10-15%; ammonium, 5-10%; and other inorganics, 15-20%. Ammonium nitrate generated via gas-to-aerosol conversion in a warm and stagnant atmosphere largely contributed to the regional transport of PM₁₀ aerosols in the high-PM₁₀ severe haze days in South Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.3
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• pp.163-170
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• 2016

Heading time is important element for yield and quality in crops. Among day length and temperature which influence on heading, temperature effect has not been investigated well. To investigate temperature effect on heading, heading date and plant growth characters were checked under the low and high temperature conditions in short day length. Analyzing heading date of six Korean varieties under the high and low temperature condition, heading date of varieties were delayed under low temperature. In the low temperature condition, dry weight and area of leaf were reduced. Varieties showing more delay of heading under low temperature also showed more reduction in leaf area. After selecting three varieties showing significant difference in leaf growth and heading date under different temperature conditions, nutrient contents of plant were analyzed. Nitrogen content was reduced in leaf and shoot under the low temperature condition. OsNRT2.3, nitrate transporter, was significantly down regulated in varieties showing more heading delay. Available phosphate content was decreased in leaf, but increased in shoot due to reduction of phosphate mobility. OsPT1, phosphate transporter regulating phosphate uptake, was more down regulated in varieties showing more heading delay. OsPT6, phosphate transporter regulating phosphate transport in plant, was also significantly down regulated in those varieties. With these data, we expected that active nitrogen and available phosphate uptake and transport in plant would increase leaf growth then might reduce heading delay under the low temperature condition.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1755-1762
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• 2013

A graphene-Zn/Al layered double hydroxide composite film was simultaneously prepared by electrochemical deposition on the surface of a glassy carbon electrode (G-LDH/GCE) from the mixture solution containing GO and nitrate salts of $Zn^{2+}$ and $Al^{3+}$. The modified electrode showed good electrochemical performances toward the simultaneous electrochemical detection of hydroquinone (HQ), catechol (CA) and resorcinol (RE) due to the unique properties of graphene (G) and LDH such as large active surface area, facile electronic transport and high electrocatalytic activity. The redox characteristics of G-LDH/GCE were investigated with cyclic voltammetry and differential pulse voltammetry. The well-separated oxidation peak potentials, corresponding to the oxidation of HQ, CA and RE, were observed at 0.126 V, 0.228 V and 0.620 V respectively. The amperometric response of the modified electrode exhibited that HQ can be detected without interference of CA and RE. Under the optimized conditions, the oxidation peak current of HQ is linear with the concentration of HQ from 6.0 ${\mu}M$ to 325.0 ${\mu}M$ with the detection limit of 0.077 ${\mu}M$ (S/N=3). The modified electrode was successfully applied to the direct determination of HQ in a local tap water, showing reliable recovery data.

• Asian Journal of Atmospheric Environment
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• v.10 no.2
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• pp.114-123
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• 2016

A change in chemical compositions of Asian dust (AD) particles can dramatically alter their optical properties, cloud-forming properties, and health effects. The present study was undertaken to evaluate this aging of AD particles by means of two complementary methods (i.e., the traditional spot test and the most advanced micro-PIXE analytical technique) for single particle analysis. Size-classified particles were sampled at the rural peninsula of Korea (Byunsan, 35.37N; 126.27E) during AD event and non-AD period in 2004. Sulfate was principally enriched on the particles in the size range of $7.65-10.85{\mu}m$ collected during AD event. The average number fraction of coarse particles ($>2.05{\mu}m$) containing chloride was 16.2% during AD event. Relatively low particles containing nitrate compared to those containing sulfate and chloride were found in AD event. Micro-PIXE elemental maps indicated that a large number of AD particles were internally mixed with man-made zinc. The highest peaks of EC and OC concentrations were appeared at $0.01-0.43{\mu}m$ particle aerodynamic diameter. High EC concentration in $PM_1$ was might be caused by the Saemangeum Seawall Project that was being conducted during our field measurement.

• Microbiology and Biotechnology Letters
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• v.19 no.2
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• pp.153-157
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• 1991

Intracellular enzymes of an extreme halophilic bacterium, Halobacterium sp. HE10, isolated from a saltern in Korea was investigated. The membrane-bound enzyme, NADH dehydrogenase, involved in electron transport system was stimulated by the addition of 2.0 M NaCl. The respiratory enzyme activities such as NADH oxidase and NADH dehydrogenase was decreased on removal of $Na^+$ ion and restored when replaced with cations like $K^+$, $Li^+$and $NH_{4}^{+}$ ions. Furthermore, their activities were affected by the anions such like carbonate, acetate, sulfate, chloride and nitrate at the presence of $Na^+$ion. Lactate dehydrogenase activity was highest at the asturated solution of NaCl and isocitrate dehydrogenase activity was a maximum level at 1.0 M NaCl. These results suggested that the enzyme activites of the respiratory chain in Halobacterium sp. EH10 was stimulated by the presence of $Na^+$ ion.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.1
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• pp.79-90
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• 1996

Total suspended particles were measured at Kosan, Cheju Island, Korea during the period of March 11 .sim. April 19, 1994. Concentrations of non-sea salt(nss) ions were higher than those measured at clean marine areas in Japan and other background marine areas in the world. Especially, nss sulfate concentration is compatable to thoes measured at Seoul. It is suggested that most nss sulfate concentration is originated from anthropogenic sources. Nss sulfate concentration shows strong correlation with ammonium and nss potassium concentrations while shows no a pparent correlation with nitrate and nss calcium concentrations. Nss calcium concentrations shows strong correlation with nss potassium and mss magnesium concentrations. It is deduced that nss potassium has two origins, one anthropogenic, the other crustal. Backward trajectory analysis results show the trajectories of air parcel during the measurement period were mostly originated from China. It is shown that cases of high nss sulfate with high nss calcium can occur when an air parcel originated from arid and semi-arid regions of morthwestern China or Mongolia passes through northeastern China.

• Progress in Superconductivity
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• v.7 no.1
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• pp.52-57
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• 2005

[ $YBa_{2}Cu_{3}O_y$ ] superconducting films were prepared on $LaAlO_3$(100) single crystal substrate by spray pyrolysis method. The precursor solution was prepared by dissolving nitrate powders in de-ionized water. Both of ultrasonic and concentric nebulizers were used in order to generate fine droplets of precursor solution. C-axis oriented films were obtained at deposition temperature of $750\~850^{\circ}C$ and working pressure of 100 Torr and 500 Torr. In case of ultrasonic nebulizer, films showed rough and porous surface morphology due to formation of enormous droplets, while smooth and dense films were obtained for concentric nebulizer. A transport $J_c$ value of $0.43\;MA/cm^2$ at 77 K and self field was achieved on $LaAlO_3$(100) single crystal substrate.

• Journal of the Korean earth science society
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• v.43 no.2
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• pp.283-302
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• 2022

Despite the nationwide COVID-19 lockdown in China since January 23, 2020, haze days with high PM₁₀ levels of 88-98 ㎍ m^-3 occurred on February 1 and 2, 2020. During these haze days, the East Asian region was affected by a warm and stagnant air mass with positive air temperature anomalies and negative zonal wind anomalies at 850 hPa. The Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) was used to analyze the variation of regional PM₁₀ aerosol transport in Korea due to decreased anthropogenic emissions in East Asia. The base experiment (BASE), which applies the basic anthropogenic emissions in the WRF-Chem model, and the control experiment (CTL) applied by reducing the anthropogenic emission to 50%, were used to assess uncertainty with ground-based PM₁₀ measurements in Korea. The index of agreement (IOA) for the CTL simulation was 0.71, which was higher than that of BASE (0.67). A statistical analysis of the results suggests that anthropogenic emissions were reduced during the COVID-19 lockdown period in China. Furthermore, BASE and CTL applied to zero-out anthropogenic emissions outside Korea (BASE_ZEOK and CTL_ZEOK) were used to analyze the variations of regional PM₁₀ aerosol transport in Korea. Regional PM₁₀ transport in CTL was reduced by only 10-20% compared to BASE. Synthetic weather variables may be another reason for the non-linear response to changes in the contribution of regional transport to PM₁₀ in Korea with the reduction of anthropogenic emissions in East Asia. Although the regional transport contribution of other inorganic aerosols was high in CTL (80-90%), sulfate-nitrate-ammonium (SNA) aerosols showed lower contributions of 0-20%, 30-60%, and 30-60%, respectively. The SNA secondary aerosols, particularly nitrates, presumably declined as the Chinese lockdown induced traffic.