• 한국대기환경학회지
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• 제12권1호
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• pp.55-66
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• 1996

One-hour average concentrations of ground-level ozone from around 80 monitoring stations in Korea during 1991 to 1993 were analyzed to examine characteristics of the ozone concentration variations. Two types of variations were observed: one was for the Capital area typified by Kwanghwmun, and the other was for the south and east seashore region typified by Tongkwangyang. In the Capital area including Seoul, Inchon, Kyonggi-do and Chunchon, mean daily 1-hout maximum was the highest in June following high monthly averages in spring. But frequent precipitation prevented further rise of daily maximum in July and August even though there were frequent episodes of high concentration exceeding 100ppb. In the south and east seashore region, average concentration was the highest throughout the year, and daily maximum and minimum simultaneously changed owing to small contributions from photochemical reactions. The typical annual variation was spring peak, summer down, and fall rise. Spring peak accompanied an usual observations of background variations at remote sites in the Northern Hemisphere. Riess of average and daily maximum with lower daily minimum in fall were attributable to photochemical reactions.

• 분석과학
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• 제8권4호
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• pp.835-841
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• 1995

The quantitation of inorganic anions in various drinking waters were investigated using capillary electrophoresis(CE) and the results were compared with ion chromatography(IC). With CE, in contrast to IC, was demonstrated rapid analysis, good efficiency, a low detection limit and the low comsumption of a solvent and samples. CE analysis was used 5 mM sodium chromate(pH 8.0) containing 20 mM tetraalkylammoniumbromide at -25kV applied voltage with indirect UV detection at 254 nm. This results in exceedingly short analysis time within 3 min. with efficiencies approaching 200,000 theoretical plates. The coefficients of variants of migration time are less than 0.8% and those of peak area are less than 2.3%. Detection limits for quantitative determination were 300 ppb-50 ppm level. These optimum conditions are applicable to various samples without pretreatment.

• Carbon letters
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• 제1권2호
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• pp.82-86
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• 2000

The present research was undertaken to evaluate the possibility of water purification filter with activated carbon fibers (ACFs) using a very low cost precursor consisting of phenolic resin coated on glass fibers. The simplified procedure involving coating, curing and activation and a very low cost glass fiber as a raw material were adopted in order to reduce manufacturing cost. The breakthrough curves of the manufactured ACFs and the commercial activated carbon (AC, Calgon F-200) were investigated in the initial concentration range from 19 to 49 ppm for benzene, toluene and ethylbenzene. From breakthrough profiles, the manufactured ACFs had significantly faster adsorption kinetics than the AC. Especially the benzene breakthrough curves, the manufactured ACF (13 g of ACF with 32% of carbon on the glass) was over the limited level (5 ppb) after flowing of 32 l at initial concentration of 15 ppm, while the commercial AC was shown about 3 ppm in initial adsorption.

• Corrosion Science and Technology
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• 제10권4호
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• pp.151-155
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• 2011

The iron oxide particles could be resulted from the corrosion of the circulating water system of a power plant. Because it may be one of the trouble materials which affect the power generation efficiency due to the deposition on steam generator tube and turbine blade, the continuous observation of its concentration is very important. The laser induced break-down detection (LIBD) technology was applied to monitor continuously the concentration of corrosion products with the detection limit of ppb level. The measurement system consists of a Nd:YAG pulsed laser, a polarizing beam splitter, a flow-type sample cell, an acoustic emission sensor, a high speed data acquisition board, a personal computer, etc.. The performance test results confirmed that this technology can be effective to monitor the corrosion product concentration of the circulating water system of a power plant.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.145-145
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• 2003

To evaluate the effect of PAHs on fertilization and larval development of the Pacific oyster, Crassostrea gigas via in vivo exposure for 30 days. Conditioned C. gigas adult brood stock was taken from oyster farm in May 2003 and raised in flow through tank at 20-22$^{\circ}C$ with feeding equivalently mixed marine microalgae: Chaetoceros simplex, C. gracilis, Isochrysis galbana and Tetrasemis tetrathele. The oysters were exposed to PAHs cocktail at 200ppb (10 species) until they are fully riped with an untreated group. Motility of sperm, Fertilization and The percent of D-shaped larvae was measured under microscope (Olympus BX-50). Fertilization capability using dry sperm and eggs from both non- and PAHs treated brood stocks was significantly reduced at the treated group (P<0.01). In addition to the origin effect, it was obvious that fertilization of eggs from both group were adversely suppressed in consistent with PAHs level (P<0.01). The percent of D-shaped larvae in treated group was significantly reduced comparing to non-treated. The percent was adversely correlated with PAHs level, which was more significantly reduced in treated group. Therefore, it was obvious that PAHs exposure on the Pacific oyster has adverse affects on the sperm as well as larvae in both maternal and acute source.

• 한국대기환경학회지
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• 제14권6호
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• pp.545-554
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• 1998

The diurnal variation of O3 concentration shows two peaks, the first peak at noontime and the secondary peak at night. In order to show why the secondary peak, high nocturnal O3 concentration, occurs without sunlight which is a essential factor of a photochemical response, the O3 concentration, several weather elements and synoptic weather map were used for June∼September at 1995, 1996. The mean concentration of high nocturnal O3 concentration days is higher by 5.4 ppb than that of low nocturnal O3 concentration days. The nocturnal O3 concentration is higher than that of diurnal O3 concentration during high nocturnal O3 concentration days, at July, 1995 and June, 1996. The high nocturnal O3 concentration is related to low air pressure, high cloud cover and high wind speed. The correlation coefficient, r. between nocturnal O3 concentration and wind speed, pressure and cloud cover is 0.387, -0.218, and 0.194, respeftiviely. It is interesting that the O3 concentration increases at Pusan when the typhoon passes by. The same result showed at Taegu when the typhoon FAYE passed by. According to the analysis of nocturnal O3 concentration for June∼September at 1995 and 1996, it seems that the high nocturnal O3 concentration relates to the trough and cyclones passing by Pusan.

• 한국환경과학회지
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• 제13권9호
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• pp.767-777
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• 2004

This study evaluated the technical feasibility of the application of $TiO_2$ photocatalysis for the removal of volatile hydrocarbons(VHC) at low ppb concentrations commonly associated with non-occupational indoor air quality issues. A series of experiments was conducted to evaluate five parameters (relative humidity (RH), hydraulic diameter (HD), feeding type (FT) of VHC, photocatalytic oxidation (PCO) reactor material (RM), and inlet port size (IPS) of PCO reactor) for the PCO destruction efficiencies of the selected target VHC. None of the target VHC presented significant dependence on the RH, which are inconsistent with a certain previous study that reported that under conditions of low humidity and a ppm toluene inlet level, there was a drop in the PCO efficiency with decreasing humidity. However, it is noted that the four parameters (HD, RM, FT and IPS) should be considered for better VHC removal efficiencies for the application of $TiO_2$ photocatalytic technology for cleansing non-occupational indoor air. The PCO destruction of VHC at concentrations associated with non-occupational indoor air quality issues can be up to nearly 100%. The amount of CO generated during PCO were a negligible addition to the indoor CO levels. These abilities can make the PCO reactor an important tool in the effort to improve non-occupational indoor air quality.

• 한국대기환경학회지
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• 제15권6호
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• pp.779-789
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• 1999

To support daily ground-level $O_3$ forecasting in Seoul, a transfer function model(TFM) has been developed by using surface meteorological data and pollutant data(previous-day [$O_3$] and [$NO_2$]) from 1 May to 31 August in 1997. The forecast performance of the TFM was evaluated by statistical comparison with $O_3$ concentration observed during September it is shown that correlation coefficient(R), root mean squared error(RMSE), normalized mean squared error(NMSE) and mean relative error(MRE) were 0.73, 15.64, 0.006 and 0.101, respectively. The TFM appeared to have some difficulty forecasting very high $O_3$ concentrations. To compare with this model, multiple regression model(MRM) was developed for the same period. According to statistical comparison between the TFM and MRM. two models had similar predictive capability but TFM based on $O_3$ concentration higher than 60 ppb provided more accurate forecast than MRM. It was concluded that statistical model based on TFM can be useful for improving the accuracy of local $O_3$ forecast.

• Mycobiology
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• 제36권4호
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• pp.255-259
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• 2008

The effect of aflatoxin-contaminated corn on albino mice was investigated using the sperm morphology assay. Blood parameter levels including; total white blood cells (WBC), total red blood cells (RBC), packed cell volume (PCV), serum bilirubin (SB) and fasting blood sugar (FBS) were also determined in the tested mice. Test mice were exposed to aflatoxin-contaminated corn (contamination level of 100 ppb) for $1{\sim}4$ weeks while aflatoxin-free corn and cyclophosphamide were used as negative and positive controls, respectively. Sperm cells showed varieties of morphological abnormality when assessed after 5 weeks. The percentage frequencies of the negative and positive controls were 18.8% and 48.87%, respectively, while the percentage abnormalities for the 1, 2, 3 and 4 weeks exposures were 41.38%, 48.17%, 57.13% and 61.67%, respectively. PCV, WBC, total bilirubin and glucose level values of mice in all concentrations were higher and statistically significant as compared to the negative control values using Dunnett's test. Therefore, abnormal sperm cell induction is concentrationdependent such that continuous consumption of aflatoxin-contaminated corn is capable of negatively affecting spermatogenesis by inducing or increasing the frequency of morphologically abnormal sperm cells produced.

• 한국환경과학회지
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• 제6권3호
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• pp.277-283
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• 1997

SPME deuce was applied to determine the THM in an aqueous solution. The 6 kinds of THM was quantitatively detenuned by using GC-ECD which has the sample eutracted on the SPME fiber from an aqueous solution for 10 min. The THM components were well separated from $CHCl_3$ to the last $CHBr_3$ UHh 13 mons at the condition. 6 kinds of the volatile halogenated organic compounds: $CHCl_3$, $CHBrCl_2$, $CHBrtCl_2$, $CHCl_3$, $C_2Cl$. and $CHBr_3$, showed well defirled calibration graph with good llnearlty from a few ppb level up to several tens of pub concentration. $CHBr_2Cl$ and $C_2C1_4$ were detected from a few samples among the 10 of river samples. CHCl3, however, was detected In 4 sea water samples with the highest of 10 ppd among the pouuted 6 positions. Trace level of $CHBr_2Cl$ and few pub level of $CHBr_3$ were also detected at the other two sample stations. Most of the 13 rain water samples collected from 6 sampling stations were contained ppd level of $CHCl_3$, and also $CHBr_2Cl$, and C_2Cl_4$ were only detected at trace level at a few rain samples among them. We could recognize the fact that our Ut and water enoronment has already been contaminated by certain volatile halogenated organic compounds through this study.