• Analytical Science and Technology
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• v.31 no.3
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• pp.122-133
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• 2018

In this study, groundwater quality data measured for 11 years from 2006 to 2016 were analyzed statistically for 101 civil defense emergency water supply facilities (CDEWSF) in the Gwangju area. The contamination level was quantified into four grades by using excess drinking water quality standards, average concentration analysis, and tendency analysis results for each facility. On the basis of this approach, the groundwater contamination degree of each item was evaluated according to land use status, installation year, depth, and geological distribution. The contamination grade ratios, which were obtained by analyzing three contamination indicators (water quality exceeded frequency, average concentration analysis, and trend analysis) for 15 items on statistically significant of civil defense emergency water was relatively high, in the order of Turbidity (51.5 %) > Color (32.7 %) > Nitrate nitrogen (28.7 %) > Hardness (25.7 %). As a result of the contamination grade analysis, except for the items of Turbidity, Color, and Nitrate nitrogen, the contamination levels were distributed in various degrees from "clean (0)" to "seriously contaminated (3)." Regarding the contamination grade of 12 items, 25 % of the total were classified as "possibly contaminated (1)," and 75 % were rated "clean (0)." The four items (Turbidity, Color, Nitrate nitrogen, and Hardness) for which contamination indication rate were evaluated as "high" by the were visualized on a contamination map.

• Journal of The Korean Astronomical Society
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• v.40 no.1
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• pp.17-28
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• 2007

We present wide-field $JHK_s$-band photometric observations of the three compact H II regions G48.9-0.3, G49.0-0.3, and G49.2-0.3 in the active star-forming region W51B. The star clusters inside the three compact H II regions show the excess number of stars in the $J-K_s$ histograms compared with reference fields. While the mean color excess ratio $(E_{J-H}/E_{H-K_s})$ of the three compact H II regions are similar to ${\sim}2.07$, the visual extinctions toward them are somewhat different: ${\sim}17$ mag for G48.9-0.3 and G49.0-0.3; ${\sim}23$ mag for G49.2-0.3. Based on their sizes and brightnesses, we suggest that the age of each compact H II region is ${\leq}2\;Myr$. The inferred total stellar mass, ${\sim}1.4{\times}10^4M_{\odot}$, of W51B makes it one of the most active star forming regions in the Galaxy with the star formation efficiency of ${\sim}10%$.

• Bulletin of the Korean Chemical Society
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• v.31 no.10
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• pp.2873-2876
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• 2010

Excess free iron generates oxidative stress that may contribute to the pathogenesis of various causes of neurodegenerative diseases. Previous studies have shown that one of the primary causes of increased brain iron may be the release of excess iron from intracellular iron storage molecules. In this study, we attempted to characterize the oxidative damage of DNA induced by the reaction of ferritin with $H_2O_2$. When DNA was incubated with ferritin and $H_2O_2$, DNA strand breakage increased in a time-dependent manner. Hydroxyl radical scavengers strongly inhibited the ferritin/$H_2O_2$ system-induced DNA cleavage. We investigated the generation of hydroxyl radical in the reaction of ferritin with $H_2O_2$ using a chromogen, 2,2'-azinobis-(2-ethylbenzthiazoline-6-sulfonate) (ABTS), which reacted with ${\cdot}OH$ to form $ABTS^{+\cdot}$. The initial rate of $ABTS^{+\cdot}$ formation increased as a function of incubation time. These results suggest that DNA strand breakage is mediated in the reaction of ferritin with $H_2O_2$ via the generation of hydroxyl radicals. The iron-specific chelator, deferoxamine, also inhibited DNA cleavage. Spectrophotometric study using a color reagent showed that the release of iron from $H_2O_2$-treated ferritin increased in a time-dependent manner. Ferritin enhanced mutation of the lacZ' gene in the presence of $H_2O_2$ when measured as a loss of $\alpha$-complementation. These results indicate that ferritin/$H_2O_2$ system-mediated DNA cleavage and mutation may be attributable to hydroxyl radical generation via a Fenton-like reaction of free iron ions released from oxidatively damaged ferritin.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.1
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• pp.15-26
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• 2022

3D open-field farm model developed from UAV (Unmanned Aerial Vehicle) data could make crop monitoring easier, also could be an important dataset for various fields like remote sensing or precision agriculture. It is essential to separate crops from the non-crop area because labeling in a manual way is extremely laborious and not appropriate for continuous monitoring. We, therefore, made a 3D open-field farm model based on UAV images and developed a crop segmentation model using a supervised machine learning algorithm. We compared performances from various models using different data features like color or geographic coordinates, and two supervised learning algorithms which are SVM (Support Vector Machine) and KNN (K-Nearest Neighbors). The best approach was trained with 2-dimensional data, ExGR (Excess of Green minus Excess of Red) and z coordinate value, using KNN algorithm, whose accuracy, precision, recall, F1 score was 97.85, 96.51, 88.54, 92.35% respectively. Also, we compared our model performance with similar previous work. Our approach showed slightly better accuracy, and it detected the actual crop better than the previous approach, while it also classified actual non-crop points (e.g. weeds) as crops.

• Journal of the Korean earth science society
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• v.27 no.5
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• pp.557-568
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• 2006

We present CCD UBVI photometry for more than 10,000 stars in $20'.5{\times}20'.5$ field of the halo globular cluster M30. From a color-magnitude diagram, main sequence turnoff was obtained when $V_{TO},\;(B-V)_{TO},\;and\;(V-I)_{TO}\;are\;8.63{\pm}0.05,\;0.44{\pm}0.05\;and\;0.63{\pm}0.05$, respectively. From a (U-B)-(B-V) diagram, reddening parameter, E(B-V) equals $0.05{\pm}0.01$ and a UV color excess ${\delta}(U-B)\;is\;0.27{\pm}0.01$. The abundance is derived, where [Fe/H] equals $-2.05{\pm}0.09$ according to the photometric method and spectroscopic data. The observed luminosity function of M30 shows an excess in the number of red giants relative to the number of turnoff stars, when comparing with the predictions of canonical models. Using the Hipparcos parallaxes for subdwarfs, we estimate distance modulus, $(m-M)_o\;as\;14.75{\pm}0.12$. Using the R and R' method, we find helium abundances, Y(R) as $0.23{\pm}0.02$, Y(R') as $0.29{\pm}0.02$, respectively. Finally, the cluster' sage dispersion was deduced from 10.71 Gyr to 17 Gyr.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.57.2-57.2
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• 2014

Red active galactic nuclei (AGNs) are supposed to be transitional objects becoming normal AGNs in the galaxy evolution scenario. So far, ~200 red AGNs have been found by very red color in optical through NIR wavelength (e.g., r'-K >5 and J-K>1.3; Urrutia et al. 2009). Here, we compare nuclear activities of the red AGNs to those of normal AGNs to verify the evolutionary phase of the red AGNs. In order to study the nuclear activities of the red AGNs, we use broad emission lines of $P{\beta}$ ($1.28{\mu}m$) of which flux is less suppressed by a factor of 100 than the $H{\beta}$ line in the case of the red AGNs with a color excess of E(B-V)=2 mag. We use 16 red AGNs discovered in previous red AGN surveys by using SDSS, 2MASS, and FIRST (Glikman et al. 2007; Urrutia et al. 2009) at z ~0.7 for which $P{\beta}$ lines are redshifted to the sky window at ${\sim}2.2{\mu}m$. The mean Eddington ratio of the 16 red AGNs is 0.562, and that of the normal AGNs is 0.320, which indicates the red AGNs include more active black hole (BH) than the normal AGNs. To test how significantly the nuclear activities of the red AGNs and the normal AGNs are different, we perform a two-dimensional Kolmogorov-Smirnov test (K-S test) on their Eddington ratio distributions. The K-S test shows the maximum deviation between the cumulative distributions, D, is 0.48, and the probability of null hypothesis, p, is even less than 0.001. This result is consistent with a picture of that the red AGNs are in intermediate phase between the stage of merger-driven starburst galaxy and the normal AGN.

• Journal of Korean Society of Water and Wastewater
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• v.8 no.3
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• pp.9-18
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• 1994

Activated sludge pilot plant testing was conducted to determine the ability of a well-designed activated sludge treatment system to remove chromic toxicity from the bleached kraft pulp mill effluent. Removals of conventional(BOD and SS) and nonconventional(resin and fatty acids, color, AOX) pollutants were estimated. The pilot plant was operated at steady state for about 10 weeks at an F/M of 0.28 and a sludge age of 8.4 days. The average MLSS concentration was 4,309mg/l, of which volatile fraction was 57%. During the operation period, the BOD removal reaction rate(k) was determined to be 8.2/day at $30^{\circ}C$. The BOD removal was 84 percent, which was 3 to 6 percent lower than expected for full-scale treatment. The chronic toxicity of the activated sludge effluent was tested by employing both Dinnel and the BML protocols. It was found that the pilot plant could achieve in excess of 90 percent reduction in chronic echinoderm toxicity. The data show slight reduction of color and AOX across the activated sludge system. The pilot system, however, demonstrated on excellent removal of resin and fatty acids.

• Economic and Environmental Geology
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• v.26 no.1
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• pp.107-114
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• 1993

For the blue sapphires from Santung, China, the color change before and after has been investigated by UV-Visible spectrophotometry method. The blue sapphires from Shantung show four groups of absorption bands: the bands A (374, 386 and 450 nm) being attributed to single $Fe^{3+}$ ion, the band B (560, 579 and $704n{\breve{m}}$) to $Fe^{2+}$/$Ti^{4+}$ pairs, the band C (-800 nm) to $Fe^{2+}$/$Fe^{3+}$ pairs, and the D (528 nm) to $Ti^{3+}$ dd transitions. From those UV-VIS characteristics the origin of blue color of the sapphires is confirmed to be attributed by the factors such as $Fe^{2+}$/$Fe^{3+}$ and $Ti^{3+}$/$Ti^{4+}$. The absorption spectra of natural blue sapphires before and after heat treatment show distintive features, comparing with those of sapphires from other localities: the bands of 689 nm and of $Cr^{3+}$ are not recorded on the spectra of sapphires from Shantung. The band (492 nm), which resulted from $Ti^{3+}$, is not shown and the intensity of the band 528 nm decreases after the heat treatment. Decoloration of ink-blue sapphires are found to be successful by heat treatment with the control of annealing and atmosphere. During the diffusion process the excess components of impurities contained originally in the host crystal were expelled to the surface of crystals, enhancing the transparency of the crystals noticeably.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.75.1-75.1
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• 2011

We investigate the connection between the presence of bars and AGN activity, using a volume-limited sample of ~6,000 late-type galaxies with axis ratio b/a > 0.6 and $M_r=-19.5+5logh$ at low redshift (0.02 < z ${\leq}$ 0.055), selected from Sloan Digital Sky Survey Data Release 7. Although bars are believed to play an important role in fueling AGNs, it is still an open question whether AGN activity is connected with the presence of bars. We find that the bar fraction in AGN-host galaxies (44.1%) is 2.5 times higher than in non-AGN galaxies (17.6%), implying an AGN-bar connection. However, this trend is simply caused by the fact that AGN-host galaxies are on average more massive and redder than non-AGN galaxies since the bar fraction increases with u-r color and velocity dispersion. When AGN-host and non-AGN galaxies with fixed u-r color and velocity dispersion are compared, the excess of bar fraction in AGN-host galaxies disappears. Among AGN-host galaxies we find no strong difference of the Eddington ratio distributions between barred and non-barred systems. These results indicate that AGN activity is not directly connected with the presence of bars.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.668-674
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• 1998

Physico-chemical qualities of pyunyuk depending on the cooking time were evaluated to produce high quality and to reduce labor and processing time. Pork headmeat divided into two parts was cooked for 1~4hrs, trimmed and pressed with 110kg/$\textrm{cm}^2$(gauge pressure) for 3.5hrs at 1$0^{\circ}C$. The contents of general nutrients, yield, texture, color, fatty acid composition, gel structure, and sensory evaluation were observed. Deboning time was very dependent on cooking time. Optimum cooking time observed in this study was 2~2.5hrs for efficiency of deboning and yield. Excess cooking time resulted in low yield and working efficiency. Yield variation depending on the cooking time was 14.3~26.0% and it was reduced by increasing the cooking time. The content of moisture was 53.5~54.8% which was not significantly different by cooking time. The content of crude fat was 14.2~26.0% which was decreased by increasing the cooking time. The contents of crude protein(21.1~26.3%) and mineral(1.4~2.7%) were increased by increasing the cooking time. The color of pyunyuk was significantly different by cooking time(p<0.05). In the texture, hardness and chewiness of the pyunyuk cooked for 2hrs were significantly higher than others processed in this study(p<0.05). However cohesiveness and springiness were not different among pyunyuks. With sensory evaluation, hardness was similar among the pyunyuks cooked over 2hrs. The pyunyuk cooked for 1hr showed higher value in juiciness than the pyunyuk cooked for 3~4hrs(p<0.05). The % of saturated fatty acids was decreased by increasing the cooking time, and gel structure of pyunyuk cooked for 2hrs was the most compact among treaments. In conclusion, 2hrs was proper as a cooking time concerned with working efficiency and physico-chemical quality of pyunpyk.