• Journal of the Korean earth science society
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• v.29 no.1
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• pp.1-12
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• 2008

A geophysical mapping was performed for Hwasan caldera which is located in Euisung Sub-basin of the southeastern part of the Korean Peninsula. In order to overcome the limitation of the previous studies, remote sensing technic was used and dense potential data were obtained and analyzed. First, we analyzed geological lineament for target area using geological map, digital elevation model (DEM) data and satellite imagery. The results were greatly consistent with the previous studies, and showed that N-S and NW-SE direction are the most dominant one in target area. Second, based on the lineament analysis, highly dense gravity data were acquired in Euisung Sub-basin and an integrated interpretation considering air-born magnetic data was made to investigate the regional structure of the target area. The results of power spectrum analysis for the acquired potential data revealed that the subsurface of Euisung Sub-basin have two density discontinuities at about 1 km and 3-5 km depth. A 1 km depth discontinuity is thought as the depth of pyroclastic sedimentary rocks or igneous rocks which were intruded at the ring vent of Hwasan caldera, while a 3-5 km depth discontinuity seems to be associated with the depth of the basin basement. In addition, three-dimensional gravity inversion for the total area of Euisung Sub-basin was carried out, and the inversion results indicated two followings; 1) Cretaceous Palgongsan granite and Bulguksa intrusion rocks, which are located in southeastern part and northeastern part of Euisung Sub-basin, show two major low density anomalies, 2) pyroclastic rocks around Hwasan caldera also have lower density when compared with those of neighborhood regions and are extended to 1.5 km depth. However, a poor vertical resolution of potential survey makes it difficult to accurately delineate the detailed structure caldera which has a vertically developed characteristic in general. To overcome this limitation, integrated analysis was carried out using the magnetotelluric data on the corresponding area with potential data and we could obtain more reasonable geologic structure.

• Korean Journal of Food Science and Technology
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• v.28 no.5
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• pp.841-849
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• 1996

Quality changes in carrot during storage were studied to investigate the efficiency, cooling properties and the washing and storage effects of hydrocooling method. As a result of plotting the nondimensionalized carrot temperature versus cooling time, its cooling rate coefficient was shown $-0.0171min^{-1}{\sim}-0.0121min^{-1}\;(R^{2}=0.99{\sim}0.95)$, and $-0.141min^{-1}{\sim}-0.0038min^{-1}\;(R^{2}=0.98{\sim}0.92)$ in package condition7. Rate of weight loss and change in moisture content of carrot were not significantly different by treatment conditions during storage at $5^{\circ}C$. During storage at $15^{\circ}C$, however, weight loss of hydrocooled carrot was lower than that of non-treated carrot from the 30th to 40th day. Especially, PE was more effective than tray for packaging hydrocooled carrots. Carrot pretreated wish sterilizing agent, packed with PE vinyl film and with residual water removed after hydrocooling showed a lower decaying-rate than any other carrots. Changes in Hunter L and b values of hydrocooled carrot were slower than those of non-treated one. The carotenoids contents of stored carrot $(0.736{\sim}0.780mg%)$ decreased to $9{\sim}43%$ after 40 days of storage at $5^{\circ}C$ and before 20 days of storage at $15^{\circ}C$. It could be presumed that the addition of sterilizing agent reduced the initial level of overall microbial and coliform counts and their growth rate during storage.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.4
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• pp.118-126
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• 2012

In this study, two types of ozone generating experimental instrument were installed in commercial livestock manure fertilization facility, which can treat hundred tons of pig manure in a day. Gas samples to be treated were collected from the upper part of the liquid fertilization system and composting system of the commercial livestock manure fertilization facility. The gas sample was flowed to oxidation reactor through pipe line by suction blower, therefore, contacted with ozone. Ammonia and sulfur compounds of gas samples collected from the inlet and outlet point of the experimental instrument were analyzed. The oxidation effect by the contact with ozone was higher in sulfur compounds than ammonia. Ammonia content was reduced about 10% by ozone contact. Sulfur compounds, on the other hand, reduced significantly while treated with ozone. In case of gas sample collected from liquid fertilization system, the concentrations of hydrogen sulfide ($H_2S$), methyl mercaptan (MM), dimethyl sulfide (DMS), and dimethyl disulfide (DMDS) of inlet gas were 50.091, 4.9089, 27.8109 and 0.4683 ppvs, respectively. After oxidized by ozone, the concentrations of sulfur compounds were 1.2317, 0.3839, 14.7279 and 0.3145 ppvs, respectively. Another sample collected from aerobic composting system was oxidized in the same conditions. The concentrations of $H_2S$, MM, DMS and DMDS of the sample collected from inlet point of the reactor were 40.6682, 1.3675, 24.2458 and 0.8289 ppvs, respectively. After oxidized, the concentrations of $H_2S$, MM, DMS, and DMDS were reduced to 3.013, ND, 8.8998 and 0.3651 ppvs, respectively. By application of another type of ozone, the concentrations of $H_2S$, MM, DMS and DMDS of inlet gas were reduced from 43.397, 1.4559, 3.6021 and 0.4061 to ND, ND, ND, and 0.21ppvs, respectively.

• KDI Journal of Economic Policy
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• v.32 no.2
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• pp.171-216
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• 2010

With the payment and settlement systems becoming more and more complex and interconnected, the issue of their interdependency rises as an important academic issue as well as a policy topic. This study examines causes, forms, and risk management of interdependencies of payment and settlement systems in Korea, and presents their current situation. By way of simulations using BOF-PSS2 developed by the Bank of Finland, we quantify the effects of an operational disruption on the payment and settlement systems so as to figure out the degree of interdependency. As a result, the secondary round effect reaches up to ￦13.6 trillion a day, which amounts to 7.8% of the daily settlement value. Furthermore, if we also consider the amount of direct operational disruption, the volume of operational disruption occupies 22.3% of total value of the daily settlement, evidencing that the interdependencies of the payment and settlement systems in Korea is enormously widespread. The secondary round effects are found to be more severe with security companies rather than with banks, and to be more depended upon when it is perceived rather than it actually happens. In case that we expand the liquidity to include cash holdings and deposits as assets, the secondary round effect dramatically decreases in all types of financial institutions while foreign banks account for more share of all the secondary round effects increases. Based on these results, we suggest various policy tasks and directions to improve the risk management of settlement systems: expansion of off-setting settlements, introduction of a new settlement system for securities transactions, rapid provision of liquidity to financial institutions, more effective monitoring on participant institutions, and intensified information sharing and cooperation among the systems.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.555-566
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• 2008

Hydrogeochemical study in Samseung area (Boeun, Chungbuk) and waterrock interaction experiment using rock samples from the area were performed to elucidate the fluoride source in groundwater and explaining geochemical behavior of fluoride ion. Fluoride concentration of public water supply mostly using groundwater in Boeun area was significantly higher in South Korea. The maximum fluoride concentration of the study area was 3.9 mg/L, and 23% of samples exceeded the Korean Drinking Water Standard of fluoride (1.5 mg/L). The average concentration of fluoride was 1.0 mg/L and median was 0.5 mg/L. Because of high skewness (1.3), median value is more appropriate to represent fluoride level of this area. The relationships between fluoride ion and geochemical parameters ($Na^+$, $HCO_3$, pH, etc.) indicated that the degree of waterrock interaction was not significant. However, high fluoride samples were observed in $NaHCO_3$ type on Piper's diagram. The negative relationship between fluoride and $NO_3$ ion which might originate from surface contaminants was obvious. These results indicate that fluoride ion in groundwater is geogenic origin. The source of fluoride was proved by waterrock interaction batch test. Fluoride concentration increased up to 1.2 mg/L after 96 hours of reaction between water and biotite granite. However, the relationship between well depth and fluoride ion, and groundwater age and fluoride ion was not clear. This indicates that fluoride ion is not correlated with degree of waterrock interaction in this area but local heterogeneity of fluoriderich minerals in granite terrain. High fluoride concentration in Boeun area seems to be correlated with distribution of permeable structures in hard rocks such as lineaments and faults of this area. This entails that the deep bedrock groundwater discharges through the permeable structures and mixed with shallow groundwater.

• Journal of the Korean earth science society
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• v.44 no.1
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• pp.13-35
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• 2023

Ocean currents play the most important role in causing and controlling global climate change. The water depth of the Yellow Sea is very shallow compared to the East Sea, and the circulation and currents of seawater are quite complicated owing to the influence of various wind fields, ocean currents, and river discharge with low-salinity seawater. The Yellow Sea Warm Current (YSWC) is one of the most representative currents of the Yellow Sea in winter and is closely related to the weather of the southwest coast of the Korean Peninsula, so it needs to be treated as important in secondary-school textbooks. Based on the 2015 revised national educational curriculum, secondary-school science and earth science textbooks were analyzed for content related to the YSWC. In addition, a questionnaire survey of secondary-school science teachers was conducted to investigate their perceptions of the temporal variability of ocean currents. Most teachers appeared to have the incorrect knowledge that the YSWC moves north all year round to the west coast of the Korean Peninsula and is strong in the summer like a general warm current. The YSWC does not have strong seasonal variability in current strength, unlike the North Korean Cold Current (NKCC), but does not exist all year round and appears only in winter. These errors in teachers' subject knowledge had a background similar to why they had a misconception that the NKCC was strong in winter. Therefore, errors in textbook contents on the YSWC were analyzed and presented. In addition, to develop students' and teachers' data literacy, class materials on the YSWC that can be used in inquiry activities were developed. A graphical user interface (GUI) program that can visualize the sea surface temperature of the Yellow Sea was introduced, and a program displaying the spatial distribution of water temperature and salinity was developed using World Ocean Atlas (WOA) 2018 oceanic in-situ measurements of water temperature and salinity data and ocean numerical model reanalysis field data. This data visualization materials using oceanic data is expected to improve teachers' misunderstandings and serve as an opportunity to cultivate both students and teachers' ocean and data literacy.

• Korean Journal of Food Science and Technology
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• v.8 no.1
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• pp.19-32
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• 1976

The laboratory Mejus as well as home-made Meju and improved Meju received from Korea were ripened in the brine for up to 8 months and the changes is the chemical composition during the process were determined and the differences between the types of Meju were compared. On the basis of the amino acid pattern, the changes in the protein quality of soybean during the process was evaluated. No significant changes in the general chemical composition of Meju were noticed during the ripening for 8 months. However, the nitrogen solubility of Meju increased for $13{\sim}29%$ to $66{\sim}78%$ during 8 month ripening of the Meju-brine mixture. The concentration of free amino-N to the total-N increased from $4{\sim}7%$ in Meju to $29{\sim}35%$ in the 8month ripened mixture. The concentration of amino-N to the total-N increased from $1{\sim}4%$ in Meju to $5{\sim}14%$ in the 8month ripened mixture and the changes varied with the type of Meju used. Remarkable changes in the amino acid pattern of soybean were occured during the ripening process. The concentration of methionine decreased to the half of original Meju during the first month of ripening. Arginine and histidine were destroyed rapidly by the ripening longer than 1 month. A considerable amount of ornithine was synthesized during the ripening. The amino acid pattern of Meju did change drastically during the ripening longer than 3 months and the changes varied with the type of Meju. The retention of the nutrients in soybean during 8 month ripening of the laboratory 3 month Meju in the brine was 49% for carbohydrates, 107% for crude fat, 93% for crude protein and 74% for the total amino acid. Histidine, arginine and methionine and 74% for the total amino acid. Histidine, arginine and methionine were the most damaged during the process, retaining only 25%, 27% and 49% of the contents in raw soybean, respectively, whereas lysine retained 79%. By the separation of the 8 month ripened mixture, approximately 60% of crude protein, all of crude fat and 80% of carbohydrates in the mixture were retained in soypaste. Soypaste contained higher concentrations of amino acids per 16gN compared to soysauce, except for lysine. The most limiting amino acid of the protein was the S-containing amino acids in all cases studied, whereas the second limiting amino acid varied from valine in soybean to threonine in most of Mejus and the brine mixtures, lysine in most of soypastes and tryptophan in some of soysauces. According to the protein quality evaluation made by the reference of the FAO provisional pattern of amino acid, the chemical score of raw soybean was 82, which was reduced to 77 by cooking and further reduced to $71{\sim}74$ by Meju fermentation. At the eighth month of ripening the chemical score of the Meju-brine mixtures were reduced to $51{\sim}66. After the separation, the chemical score of soypaste ranged from 60 to 71, whereas that of soysauce varied from 45 to 57. Generally, the products made from improved Meju recorded the highest score, whereas those made from homemade Meju showed the poorest protein quality. The essential amino acid index(EAAI) of the samples was similar to the chemical score, but it appeared to fit the overall changes in the amino acid pattern during the process better than the chemical score.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.2
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• pp.200-207
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• 2015

Various natural products or their derivatives, mostly originating from plants, fungi, and bacteria, have been exploited as therapeutic drugs to treat various human diseases. In addition to previously explored organisms, research on natural compounds has now expanded into unexamined living organisms in order to identify novel bioactive substances. Here, we determined whether or not the larval form of the mealworm beetle Tenebrio molitor, a species of darkling beetle, contains cytotoxic substances that exclusively affect cancer cell viability. Ethanol extract and its solvent partitioned fractions, hexane and ethyl acetate fractions, showed anticancer effects against various human cancer cells derived from the prostate (PC3 and 22Rv1), cervix (HeLa), liver (PLC/PRF5, HepG2, Hep3B, and SK-HEP-1), colon (HCT116), lung (NCI-H460), breast (MDA-MB231), and ovary (SKOV3). Cell death induced by the fractions was a mix of apoptosis, necrosis, and autophagy. The hexane fraction was administered intraperitoneally to nude mice bearing a hepatocellular carcinoma SK-HEP-1 and showed inhibition of tumor growth in vivo. Therefore, we concluded that worm extracts contain cytotoxic substances, which can be enriched by proper fractionation protocols, and further separation and purification could lead to the identification of novel molecules to treat human cancers.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.2
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• pp.77-84
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• 2011

This study was conducted to develop a novel combined system of a hybrid rotating biological contactor (RBC) process that was composed of an attached- and suspended- biomass reactor, followed by a settler and a biological aerated filter (BAF) column to treat a high strength slaughter wastewater. Long term influences of organic and nitrogen loading rates were investigated to see how the combined system worked in terms of the removal efficiency. A synthetic wastewater containing a pork cutlet steak source (commercially available) and swine blood was used to feed the combined system. The hybrid RBC process showed excellent removals: about 95% for soluble COD and 85% for ammonium nitrogen. However, the unsettled solids seriously deteriorated the removal efficiency of total COD (TCOD) and total nitrogen (TN) in the RBC process. A significant fraction of the TCOD and suspended solids (SS) was further removed in the BAF column although the effluent quality was still unsatisfactory, giving TCOD 300 mg/L, SS 180 mg/L and TN 59 mg/L. An addition of polyaluminium chloride into the RBC effluent improved the performance of the settler and BAF, producing an excellent quality of final effluent; TCOD 16.5 mg/L, SS 0 mg/L, TN 55.5 mg/L, TP 1.3 mg/L. Therefore, it was confirmed that the combined system of hybrid RBC and BAF could treat a high strength slaughter wastewater excellently.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.2
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• pp.164-173
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• 2018

Elevated atmospheric carbon dioxide concentration ($CO_2$) is a major component of climate change, and this increase can be expected to continue into the crop and food security in the future. In this study, Soil-Plant-Atmosphere-Research (SPAR) chambers were used to examine the effect of elevated $CO_2$, temperature, and drought on the canopy architecture and concentration of macronutrients in potatoes (Solanum tuberosum L.). Drought stress treatments were imposed on potato plants 40 days after emergence. Under AT+2.8C700 (30-year average temperature + $2.8^{\circ}C$ at $700{\mu}mol\;mol^{-1}$ of $CO_2$), at maximum leaf area, elevated $CO_2$, and no drought stress, a significant increase was observed in both the aboveground biomass and tuber, and for the developmental stage. Even though $CO_2$ and temperature had increased, AT+2.8C700DS (30-year average temperature + $2.8^{\circ}C$ at $700{\mu}mol\;mol^{-1}$ of $CO_2$ under drought stress) under drought stress showed that the leaf area index (LAI) and dry weight were reduced by drought stress. At maturity, potatoes grown under $CO_2$ enrichment and no drought stress exhibited significantly lower concentrations of N and P in their leaves, and of N, P, and K in tubers under AT+2.8C700. In contrast, elevated $CO_2$ and drought stress tended to increase the tuber Mg concentration under AT+2.8C700DS. Plants grown in AT+2.8C700 had lower protein contents than plants grown under ATC450 (30-year average temperature at $400{\mu}mol\;mol^{-1}$ of $CO_2$). However, plants grown under AT+2.8C700 showed higher tuber bulking than those grown under AT+2.8C700DS. These findings suggest that the increase in $CO_2$ concentrations and drought events in the future are likely to decrease the macronutrients and protein concentrations in potatoes, which are important for the human diet.