• Journal of Korean Society for Atmospheric Environment
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• v.22 no.5
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• pp.642-652
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• 2006

In order to understand the characteristics of surface ozone concentration and high $O_3$ concentration days, regional data from seven air quality monitoring stations which were operated by local governments were analyzed Regional characteristics of $O_3$ concentration were analyzed with the data of $O_3$ concentration and the characteristics of $O_3$ generation and weather conditions by the selection of the days in which the concentration was higher than 80 ppb. In the case of daily variation, the lowest $O_3$ concentration was shown in all regions from 7am to 8am and the highest around at 4 pm. The monthly variation of mean $O_3$ concentration and ${\Delta}O_3$ values revealed a reducing pattern in July and August following the peak in June, and again a gradual increasing trend in September and October. The result shows that the amount of ozone is dependent on photochemical reaction. The days of $O_3$ generated more than 80 ppb in the region of Gwangyang-bay were 544 days(1,760 hrs). The frequency of occurrence in the region revealed a strong pattern with the order of Samil-dong, Jinsang, and Gwangmu-dong stations in the Gwangyang region. However, Tein-dong, which is the nearest station to air pollution material generation source, showed the lowest frequency in the study area. Consequently, the meteorological parameters which can easily generate the high concentration of $O_3$ in the region of Gwangyang-bay are characterized as follows; atmospheric temperature which is higher than $19^{\circ}C$, relative humidity with the range of $60{\sim}85%$, the less average wind velocity than 5 m/s, cloud cover which is less than 5/10, and the more duration of sunshine than 8 hours.

• Economic and Environmental Geology
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• v.27 no.4
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• pp.345-361
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• 1994

Lens shaped titanomagnetite ore bodies in the Soyeonpyeong iron mine are embedded in amphibolites, which were intruded into Precambrian metasediments such as garnet-mica schist, marble, mica schist, and quartz schist. Mineral chemistry, K-Ar dating and hydrogen and oxygen stable isotopic analysis for the amphibolites and titanomagnetite ores were conducted to interpret petrogenesis of amphibolite and ore genesis of titanomagnetite iron ore deposits. Amphibolites of igneous origin have unusually high content of $TiO_2$, ranging from 0.94 to 6.39 wt.% with an average value of 4.05 wt.%. REE patterns of the different lithology of the amphibolite show the similar trend with an enrichment of LREE. Amphiboles of amphibolites are consist mainly of calcic amphiboles such as ferro-hornblende, tschermakite, ferroan pargasite, and ferroan pargasitic hornblende. K-Ar ages of hornblende from amphibolite and gneissic amphibolite were determined as $440.04{\pm}6.39Ma$ and $351.03{\pm}5.21Ma$, respectively. This indicates two metamorphic events of Paleozoic age in the Korean peninsula which are correlated with Altin orogeny in China. The titanomagnetite mineralization seems to have occurred before Cambrian age based on occurrence of orebodies and ages of host amphibolites. The Soyeonpyeong iron ores are composed mainly of titanomagnetite, ilmenite, and secondary minerals such as ilmenite and hercynite exsolved in titanomagnetite. The temperature and the oxygen fugacity estimated by the titanomagnetite-ilmenite geothermometer are $500{\sim}600^{\circ}C$ (ave. $550^{\circ}C$) and about $2{\pm}10^{-23}bar$, respectively. Hornblendes from ores and amphibolites which responsible for magnetite ore mineralization, have a relatively homogeneous isotopic composition ranging from +0.8 to +3.9 ‰ in ${\delta}^{18}O$ and from -87.8 to -113.3 ‰ in ${\delta}D$. The calculated oxygen and hydrogen isotopic compositions of the fluids which were in equilibrium with hornblende at $550^{\circ}C$, range from 2.8 to 5.9‰ in ${\delta}^{18}O_{H2O}$ and from -60.41 to -81.31 ‰ in ${\delta}D_{H2O}$. The ${\delta}^{18}O_{H2O}$ value of magnetite ore fluids are in between +6.4 to + 7.9 ‰. All of these values fall in the range of primary magmatic water. A slight oxygen shift means that $^{18}O$-depleted meteoric water be acted with basic fluids during immiscible processes between silicate and titaniferous oxide melt. Mineral chemistry, isotopic compositions, and occurences of amphibolites and orebodies, suggest that the titanomagnetite melt be separated immisciblely from the titaniferous basic magma.

• Korean Journal of Food Science and Technology
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• v.52 no.3
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• pp.304-309
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• 2020

Different types of storage containers, such as polypropylene (PP), stainless steel (STS), and ceramic were used for kimchi storage at 0℃ in a refrigerator, and the characteristics were compared for 32 days. The pH of kimchi samples in PP and STS containers reached 4.59 and 4.53, respectively at day 16, while a pH of 4.92 could be observed in ceramic containers. This trend persisted until day 32. Titratable acidities of the PP and STS container contents reached 0.83 and 0.82%, respectively, on day 16, while it reached 0.73% in the case of the ceramic container contents. The viable cell counts of lactic acid bacteria in kimchi samples in PP, STS, and ceramic containers fluctuated and finally reached 4.87, 5.44, and 5.35 Log CFU/g, respectively. Weissella koreensis occupied a large portion of the kimchi sample of the ceramic container on day 20 based on the metagenomic analysis. Taken together, ceramic container might be desirable for the storage of kimchi in low temperature refrigerators.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.417-422
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• 2003

The onions are considered to be a favorable functional source of beverage because they contain much sugar and various nutrients, and they are juicy vegetable. Recently, consumers have a new trend to take functional foods with health benefits. To meet this need, this study was the basic research to establish a manufacturing process of functional onion beverage by glucose oxidase. Glucose oxidase catalyzes reaction of glucose oxidation and makes generation of gluconic acid. Kinetics of the reaction was also investigated, and maximum glucose consumption rate $(V_{max})$ of $26.1{\times}10^{-2}\;g/L{\cdot}min$ and $K_m$ of 5.84 g/L were obtained. Optimum conditions were obtained when the glucose oxidase catalyzed reaction was carried out at temperature of $25^{\circ}C$, agitation rate of 450 rpm and aeration rate of 4 vvm in a 2.5 L jar fermentor. Finally, the enzyme reactor was 10-times scaled up and a similar glucose oxidation performance was achieved in the scaled-up reactor.

• Journal of Ginseng Research
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• v.20 no.4
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• pp.501-519
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• 1996

There are two kinds of commercially available ginseng root, red ginseng and white ginseng processed from fresh ginseng root Those ginsengs are primary product from fresh ginseng root and have the characteristic of keeping their original root shape Processed ginseng products are made from either red ginseng or white ginseng by way of complicated process of pulverization. Extraction. Condensation, fettering, sterilization, etc. Among them there are extracts. extract powder, powder, capsules tablets, Candy, drinks, nectar, jelly, gums. chicken soup. tonic. etc. to meet the demand for consumer's pretheronce . The 200 kinds of processed secondary products are approximately produced in the form of 20 kinds of ginseng products by about 60 domestic companies. In spite of about 213.000 million won of domestic market in 1993. it seems like that the ginseng market of the future has not a good prospects The total market sale of white ginseng in Korea has been continuously decreased since 1991 And 963 tons of white ginseng was consumed in domestic market in 1993 The domestic market sales of white ginseng in origina1 root shave. was 90, 000 million won in 1993 and market price of the fine root used as a source of processed products has not been changed in these ten years. The total market sale of red ginseng and its processed products was 58, 000 million won in 1993 9.800 mi11ion won of red ginseng in original root shape and 48.000mi11ion of processed red ginseng product. Ginseng products such as extracts, drinks, teas and tonics etc atre mostly exported to south-east Asia. And the total exports of ginseng pi.oducts (extracts, drinks teas) decreased to 54 million dollars in 1994, compared with 85 million dollars in 1992. Despite of extensive knowledge about ginseng little is still known about the development of new processed ginseng pl.oducts because of "Know-How". Some papars have presented the effects of extracting method(amounts of solvent. time. temperature, equipment. etc.) on the quality and yields of ginseng extr acts. Also. some researchers have carried out a few studies on the poriflcation of the extracts and the amounts of precipitation in the drink at variotas pH during the storage for preventinly drink from precipitation. A fell studies on the preservation of Korean ginseng powder. tea. Extract powder by irradiation and ozone treatment have been reported by some researcher for the improvement hygienic quality of ginseng products There are also some reports about the effects of ginseng components on the acid production by lactic acid bacteria or acetic acid bacteria. and alcohol production by yeast for the development of new ginseng products processed by fermentation. To make ginseng more able to contribute to the health of mankind in the future. consistent and considerable efforts should be focussed on improving the taste of ginseng and developing various new product as a health food or a function food.tion food.

• Korean Journal of Plant Resources
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• v.24 no.2
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• pp.160-167
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• 2011

Shallot is a foreign crop introduced from France in 1995 as a new overwintering field crop with an aim to develop as an export crop. During the introductory cultivation trials, several problems were raised such as premature growth depression in early summer, sensitivity to summer moisture, and weakened vigor of the seed bulbs following successive propagations. This study was conducted to develop proper cultural methods based on annual productivity and adaptability of growing area to address and suggest solutions to some of these problems. Bulb weight was 18.7 g and bulb yield per 10a was 4,113 kg in 1995. In 1996, bulb weight increased to 25.8 g, while bulbs yield per 10a deceased to 2,013 kg. This trend continued in 1997 so that bulb weight increased, and yield per 10a decreased as compared to those in 1996. However, in 1998, both bulb weight (21.1 kg) and yield per 10a (1,246 kg) decreased significantly as compared to those of the previous years. Plant growth from planting to April in the coastal area was better than in other areas. However, the plant growth thereafter until early July was better in the semi-highland area. As a result, the bulb yield in the semi-highland area was 57% more than that in the lowland areas such as the coastal area.

• Corrosion Science and Technology
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• v.10 no.4
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• pp.109-117
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• 2011

The Korean Peninsula is located in the middle latitude of the northern hemisphere and has a clear 4-seasons and shows the typical temperate climate. Because of seasonal winds, it is cold and dry by a northwestern wind in the winter and it is hot and humid by a southeast wind in the summer. Also, temperature difference between the winter and the summer is large and it shows a rainy season from June to July but recently this regular trend may be greatly changed by an unusual weather phenomena. Since the Peninsula is east high west low type, the climate is complicated too. Because these geographical and climate characteristics can affect the properties of corrosion of metals and alloys, a systematic research on atmospheric corrosion in the Peninsula is required to understand and control the corrosion behavior of the industrial facilities. This paper analyzed the atmospheric corrosion factors for several environments in the Korean Peninsula and categorized the corrosivity of atmospheric corrosion of metals and alloys on the base of the related ISO standards. Annual pH values of rain showed the range of 4.5~5.5 in Korean Peninsula from 1999 to 2009 and coastal area showed relatively the low pH's rain. Annual $SO_2$ concentrations is reduced with time and its concentrations of every major cities were below the air quality standard, but $NO_2$concentration revealed a steady state and its concentration of Seoul has been over air quality standard. In 2007, $SO_2$classes of each sites were in $P_0{\sim}P_1$, and chloride classes were in $S_0{\sim}S_1$, and TOW classes were in ${\tau}_3{\sim}{\tau}_4$.That is, $SO_2$ and chloride classes were low but TOW class was high in Korean Peninsula. On the base of these environmental classes, corrosivity of carbon steel, zinc, copper, aluminium can be calculated that carbon steel was in C2-C3 classes and it was classified as low-medium, and zinc, copper, and aluminium showed C3 class and it was classified as medium.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.230-236
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• 1988

The distributions of bacterial numbers and activities were studied bimonthly in 1987, at 3 sites in Lade Paro for elucidating the changes by disturbance of aquatic ecosystem. The total bacterial number was $0.3\times 10^{5}-13.1\times ^{5}$ cells/ml. The geterotrophic bacterial number had the variance from $1.9\times 10^{3}$ CFUs/ml to $3.1\times 10^{4}$CFUs/ml and the variation trend was similar to that of the total bacterial number. The proportions of alpha-glucosidase or beta-glucosidase releasing bacteria showed temporal changes rather than spatial changes. The proportions of phosphatase releasing bacteria had the maximum values, 22.7-83.0%, in July. The electron transpory system activity revealed the variation from $480{\mu}gO_{2}$/l/day to $1696{\mu}gO_{2}$/l/day and hagher values at upper stream and in summer. The degradation fraction by phosphatase was 0.4-9.1%/h and increased with temperature. The maximum value of heterotrophic activity was 8.2%/h in summer. Eventhough the distributions of total bacteria and heterotrophic bacteria were affected by the water disturbance but microbial activities and proportions of the specific enzume releasing bacteria were not affected.

• Journal of Environmental Science International
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• v.15 no.8
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• pp.701-718
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• 2006

The average ratio of the daily UV-B to total solar (75) irradiance at Busan (35.23$^{\circ}$N, 129.07$^{\circ}$E) in Korea is found as 0.11%. There is also a high exponential relationship between hourly UV-B and total solar irradiance: UV-B=exp (a$\times$(75-b))(R$^2$=0.93). The daily variation of total ozone is compared with the UV-B irradiance at Pohang (36.03$^{\circ}$N, 129.40$^{\circ}$E) in Korea using the Total Ozone Mapping Spectrometer (TOMS) data during the period of May to July in 2005. The total ozone (TO) has been maintained to a decreasing trend since 1979, which leading to a negative correlation with the ground-level UV-B irradiance doting the given period of cloudless day: UV-B=239.23-0.056 TO (R$^2$=0.52). The statistical predictions of daily total ozone are analyzed by using the data of the Brewer spectrophotometer and TOMS in East Asia including the Korean peninsula. The long-term monthly averages of total ozone using the multiplicative seasonal AutoRegressive Integrated Moving Average (ARIMA) model are used to predict the hourly mean UV-B irradiance by interpolating the daily mean total ozone far the predicting period. We also can predict the next day's total ozone by using regression models based on the present day's total ozone by TOMS and the next day's predicted maximum air temperature by the Meteorological Mesoscale Model 5 (MM5). These predicted and observed total ozone amounts are used to input data of the parameterization model (PM) of hourly UV-B irradiance. The PM of UV-B irradiance is based on the main parameters such as cloudiness, solar zenith angle, total ozone, opacity of aerosols, altitude, and surface albedo. The input data for the model requires daily total ozone, hourly amount and type of cloud, visibility and air pressure. To simplify cloud effects in the model, the constant cloud transmittance are used. For example, the correlation coefficient of the PM using these cloud transmissivities is shown high in more than 0.91 for cloudy days in Busan, and the relative mean bias error (RMBE) and the relative root mean square error (RRMSE) are less than 21% and 27%, respectively. In this study, the daily variations of calculated and predicted UV-B irradiance are presented in high correlation coefficients of more than 0.86 at each monitoring site of the Korean peninsula as well as East Asia. The RMBE is within 10% of the mean measured hourly irradiance, and the RRMSE is within 15% for hourly irradiance, respectively. Although errors are present in cloud amounts and total ozone, the results are still acceptable.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.1
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• pp.45-55
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• 2017

Climate change causes changes in rainfall patterns, temperature and drought frequency. Climate change impact influences on water management and crop production. It is critical issue in agricultural industry. Rice is a staple cereal crop in South Korea and Korea uses a ponding system for its paddy fields which requires a significant amount of water. In addition, water supply has inter-relationship with crop production which indicates water productivity. Therefore, it is important to assess overall impacts of climate change on water resource and crop production. A water footprint concept is an indicator which shows relationship between water use and crop yield. In addition, it generally composed of three components depending on water resources: green, blue, grey water. This study analyzed the change trend of water footprint of paddy rice under the climate change. The downscaled climate data from HadGEM3-RA based on RCP 8.5 scenario was applied as future periods (2020s, 2050s, 2080s), and historical climate data was set to base line (1990s). Depending on agro-climatic zones, Suwon and Jeonju were selected for study area. A yield of paddy rice was simulated by using FAO-AquaCrop 5.0, which is a water-driven crop model. Model was calibrated by adjusting parameters and was validated by Mann-Whitney U test statistically. The means of water footprint were projected increase by 55 % (2020s), 51 % (2050s) and 48 % (2080s), respectively, from the baseline value of $767m^2/ton$ in Suwon. In case of Jeonju, total water footprint was projected to increase by 46 % (2020s), 45 % (2050s), 12 % (2080s), respectively, from the baseline value of $765m^2/ton$. The results are expected to be useful for paddy water management and operation of water supply system and apply in establishing long-term policies for agricultural water resources.