• Journal of the Korean Society of Groundwater Environment
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• v.1 no.1
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• pp.51-58
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• 1994

Electrical soundings and mappings were conducted to elucidate the geoelectrical structures of the local area of Cheju Island. The areas of the electrical surveys are coastal areas of Cheju Island, Gwagji, Sinpung-Sincheon. Generally, the geoelectrical structures of these areas are closely related with hydrogeological structures and it is very important to elucidate the geoelectrical structures for the water supply problems. Even though the results of electrical surveys in coastal areas of Cheju Island differ from place to place, there exists a general tendency of resistivity decrease with depth and the zone in the vicinity of mean sea level has low resistivity value. Also, there is good correlation between the low resistivity zone and the ground water distribution in the survey areas. A careful examination of the results of this study enabled resistivities of the rocks in Cheju Island to be divided in some categories. The resistivities of rocks unsaturated with ground water are greater than about 1000 ohm-m. The rocks saturated with fresh water have the resistivity value of about few hundreds ohm-m. Last, the rocks saturated with saline and/or brackish water have the resistivity value of about few tens ohm-m. The subsurface resistivity distribution of Cheju Island seems to be strongly dependent on the hydraulic characteristics of the rocks, and the amount and the salinity of the ground water in the rocks rather than the surface geology of the area.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.11
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• pp.1491-1496
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• 2008

Twenty natural plants from Jeju were extracted by pressurized organic solvent (100% methanol, $40^{\circ}C$, 13.6 MPa, 10 min). Extraction yield, total phenolic content (TPC) and integral antioxidant capacity were measured, and each component was identified by GC/MS. Extraction yields were high as 21.8%, 21.5, 21.1, 20.7 and 20.1% in Rhus javanica, Euscaphis japonica, Alnus firma, Sapium japonicum and Sorbus alnifolia, respectively. The extracts containing high TPC (mg GAE/g of dry sample) were obtained from Malus sieboldii (68.3), Sapium japonicum (57.6), Pyrrosia lingua (56.6) and Euscaphis japonica (55.1). Integral antioxidant capacities of water-soluble substances were 598, 394, 293 and $270\;{\mu}mol$ ascorbic acid equivalent/g in Geranium thunbergii, Sapium japonicum, Cornus kousa and Rhus javanica, respectively. Integral antioxidant capacities of lipidsoluble substances were 611, 314, 296 and $242\;{\mu}mol$ trolox equivalent/g in Ardisia crenata, Ostrya japonica, Geranium thunbergii and Quercus acuta, respectively. Fifteen major peaks were identified by GC/MS from the extract of pressurized organic solvent from Sapium japonicum. Two polyphenols (gallic acid (retention time (RT) 19.7 min)) and quercetin (33.5 min)), ascorbic acid (RT 35.3 min), and several fatty acids (retention time 18.6, 21.0, 21.8, 21.9 and 23.6 min) were identified, and gallic acid was the major polyphenol component due to high peak area.

• 한국지구물리탐사학회:학술대회논문집
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• 2000.09a
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• pp.54-69
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• 2000

There are groundwater trouble by high-salinity yield inducing sea-water intrusion in Cheju Island. It is used groundwater-GIS(Well-lnfo) in the maintenance and management of groundwater in Cheju Island to grasp groundwater trouble area and cause of high-salinity yield. For 16 wells certain to yield high-salinity, we logged specific electrical conductivity(EC) and tried to get hold of freshwater and saltwater relationship. As result of distribution of $Cl^-$ by depth, it is showed up groundwater trouble by high-salinity yield in the east coastal area and the partly north coastal area. The reason of high-salinity groundwater yield are low-groundwater level by the structure of geology and low-hydraulic gradient etc. There is necessity for management to development and use of groundwater in the high-salinity area, special management area.

• Journal of the Korean earth science society
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• v.22 no.1
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• pp.10-19
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• 2001

There are three scoria cones and their eruptive materials in Sarabong-Byeoldobong-Hwabukbong area Cheju Island. And they made complicated volcanic stratigraphy. In Byeoldobong tuff, basalt and granite xenoliths are present. It is presumed that the granite is a kind of basement of Cheju island. And Biseokgeori hawaiite has many kaersutite phenocrysts. Therefore, this area is very important for the study about history of volcanic activity of Cheju island. The lowest beds are Shinheung basalt and Byeoldobong tuff. Byeoldobong tuff has xenoliths of granite and phenocrystalline basalt. After the formation of these rocks, the Hwabukbong volcanism commenced. First of all this volcanism formed Biseokgeori hawaiite that has lots of kaersutite, a member of amphibole group, characteristically. Over this rock, Hwabukbong scoria cone was formed. The next Sarabong volcanism effused Keonipdong hawaiite that has lots of plagioclase and olivine phenocrysts and then Sarabong scoria cone was made up. Basalt xenolith in Byeoldobong tuff is different from Shinheungri basalt with regard to petrography, therefore this offers suggestion about existence of another basalt between basement and Shinheungri basalt. Granite xenolith derived from the basement of this area has features of the Jurassic granite in the Korea Peninsula, for example a lot of myrmekitic texture, microcline, and absolute age (172.4 Ma) by K-Ar method.

• Environmental Analysis Health and Toxicology
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• v.19 no.1
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• pp.49-58
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• 2004

It is important to select a risk based priority area for environmental policy formation and decision-making. We estimated the health risks and associated damage costs from exposure to fine particles and assigned priority areas for twenty -five districts in Seoul. In order to estimate the theoretical mortality incidence of the health risk, baseline risks were estimated from mortality rates in two low level areas of fine particles, Seocho Gu and Cheju city To estimate the damage cost from the risk estimates, we investigated and estimated the willingness to pay (WTP) for specific risk reduction. We assumed two different locations as the reference area, Cheju city as Scenario I and Seocho gu as Scenario II. From the results, the five districts, Kwangjin, Chungnang, Kangbuk, Nowon, and Kangnam, ranked high in the categories of both health risk and economic risk. Damage costs were over twenty billion won in each of these districts. As there are uncertainties in these results, the parameter values such as PM$_{2.5}$ level, dose -response slope factor, baseline risk, exposure population and WTP should be continuously validated and refined.d.

• Journal of Veterinary Clinics
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• v.25 no.2
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• pp.102-105
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• 2008

The most common abnormality of the umbilicus in the foal is the patent urachus. Patent urachus may be a congenital or acquired condition in foals in which the urachus fails to close spontaneously at or shortly after parturition. A 17-day-old male Thoroughbred foal was requested to the Veterinary Pathology Laboratory of Cheju National University. The foal showed clinical signs such as umbilical urination, anorexia, depression, lethargy, and abdominal pain for 10 days. Because of the umbilical urination, the surgery for patent urachus was performed, but he died next day. Grossly, many pale yellowish foci 10-20 mm in diameter were scattered on the throughout surface of lungs. Severe subcapsular hemorrhage was observed in left kidney. Large milky yellow mass 10X6-7 cm in size was found in the adjacent area of right kidney. Histopathologically, many abscesses with bacterial cocci were scattered in the blood vessels or adjacent pulmonary parenchyma of lungs. Severe numerous abscesses with intralesional bacterial cocci were mostly occupied in the abdominal mass from right kidney. Gram staining for tissue sections demonstrated numerous Gram positive cocci in pulmonary and abdominal abscesses. In bacterial culture, catalase-positive beta-hemolytic colonies were isolated and confirmed as Staphylococcus (S.) aureus by Vitek system. Based on the results, acquired patent urachus and then multiple abscesses may be originated from the umbilical cord infected with S. aureus in this foal.

• Korean Journal of Environmental Biology
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• v.17 no.2
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• pp.175-182
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• 1999

An unprecedented mass mortality of commercially important macrobenthic animals, including Haliotis discus discus, H. diversicolor, Batilus cornutus, Sticopus japonious and Hemicentrotus puzoherrimus, occurred off the west coast of Cheju Island in summer of 1996. Phytoplankton blooms were absent along the coast. The appearances of the surface low-salinity water (SLSW) off the coast of Cheju Island preceded the mass mortality, leading to speculation that the low-salinity stress may have a crucial role in the mass mortality. Since there was no heavy rain for the same period, the precipitation was not a possible explanation for the decrease of salinity. Physical oceanographic data taken by NFRDI (1997) clearly indicated that the SLSW was present in the area between China and Cheju Island in August 1996. This is most likely due to a freshwater supply resulting from the existence of large river runoff. Evidence of the current and the distance between the Yangtz River and Cheju Island also supports the hypothesis that source of the SLSW was the freshwater originated from the Yangtz River runoff.[macrobenthic animals, mass mortality, surface low-salinity water].

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1997.11a
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• pp.145-159
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• 1997

Cheju Island is the most attractive resort area in Korea for its exotic landscape, natural beauty, and traditional culture which is quite different from that of the mainland. Until now, most of the recreational facilities and accomodations have been constructed along the coastal areas. Recently, mid-mountain area has been under very heavy development pressure because it is suitable for new sites for tourism facilities and the land price in the coastal area is very high. The mid-mountain area is the land located 200-600m above the sea level. It is a major source of water supply for the island and has exotic scenic beauty, which cannot be found in mainland but it is the area very vulnerable to water pollution Therefore, it is very important to manage this area based on the concept of environmentally sound and sustainable development in order to meet ever increasing demand for the land development The purposes of this project are: 1) to establish Geographic Information System for the whole island, 2)to formulate environmentally sound landuse plat However, There has been accuracy of the original map, defining criteria of analysis, updating of the data were identified for future tasks to be studied.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.4
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• pp.247-254
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• 1991

Mackerel purse seine fishery is one of the most important fisheries in Korea and its annual mean catch from 1982 to 1988 is 350 thousand tons. Between 1982 and 1988, the characteristics of catch at 5 sectors of the sea area was analyzed according to operating sea block and the catch by fishes based on the data obtained from daily report of fishing condition that had been made out by 48 Korean fishing boats engaged in the fishery of purse seine. In these 5 sectors of the sea area, catch per net hauling in the coastal area of Cheju Island is less than that in the other sectors. Accordingly, the shape of fishing gear during operation has been measured to analyzed the deformation of net shape caused by the bottom current. (The lunar calender is used in the paper) The results obtained are as follows; The average CPUE of purse seines is 31.6 tons and it is higher from October to April than that from May to September. In the 5 purse seine fishing grounds, the ratio of net haul in the coastal sea area of cheju Island is 42.4% and it is the highest level, but the CPUE is 25.7 tons which is relatively low level. Each CPUE in the sea areas is significant differences with 1% level. Index of seasonal variation of mackerel CPUE from May to October is lower than the standard value, whereas index from November to January is higher. The diameter of circle by net shooting becomes shorter to the minimum caused by the bottom current during loose set, becomes narrower and the efficiency of fish encirclement becomes lower. The shape of leadline by bottom current becomes long oval type along with current direction in the tight set, while it becomes long oval type in the direction of a right angle to the current direction and the enclosed area is reduced hurriedly, and the deformation of net is most serious in the loose set.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.4
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• pp.487-498
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• 2006

Total 438 precipitation samples were collected in Jeju City between 1997 and 2005, and their major ionic components were analyzed. The comparison tests using ion balance, electric conductivity and acid fraction were performed. It was found their correlation coefficients were in the range of 0.977$\sim$0.994, indicating the good quality of collected dam. The volume-weighted mean pH and electric conductivity were 4.8 and 23.0 $\mu$S/cm, respectively. with the ionic strength of 0.23$\pm$0.20 mM. The marine ($Na^+$, $Mg^{2+}$, and $CI^-$), anthropogenic (nss$SO_4{2-}$, $NO_3^-$, and $NH_4^+$) and soil (nss-$Ca^{2+}$) species have contributed to the ionic components of precipitation samples with 43$\sim$74%, 16$\sim$37% and $\sim$5%, respectively. The seasonal variations of $NO_3^-$ and nss-$SO_4^{2-}$ showed a distinct seasonality with higher concentrations in winter than summer, indicating an increase of fossil fuel consumption and a possibility of long-range transport of those pollutants from continental area along the dominant winter westerly. The levels of nss-$Ca^{2+}$ also were appeared the highest in winter and increased comparatively in spring season. possibly due to the soil influences including the Asian Dust. The acidification contribution of nss-$SO_4^{2-}$ and $NO_3^-$ showed 88$\sim$96%, and the free acidity was in the range of 6.0$\sim$40.1%. Interestingly, the backward trajectories for the case of upper 10% nss-$SO_4^{2-}$ and $NO_3^-$ levels have passed through the China continent before their arrival to Jeju. The precipitation of pH below 4.5 has been occurred frequently when the trajectory's path lied over the China continents. On the other hand, the air masses from the North Pacific area were characterized by lower 10% of nss-$SO_4^{2-}$- and $NO_3^-$ concentration, which demonstrated that air mass from the North Pacific was the cleanest among air masses moved to Jeju.