• Economic and Environmental Geology
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• v.55 no.6
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• pp.671-687
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• 2022

It has been reported that about 47% of groundwater wells within 10 km from the coastline in the western/southern coastal areas of Korea were affected by seawater. It has been interpreted that the cause of groundwater salinization is seawater intrusion. The Gilsan stream in the Seocheon area was a tidal stream until the Geumgang estuary dam was constructed and operated. Therefore, it is likely that the Gilsan stream catchment was deposited with sediments containing high-saline formation water prior to the use of landfill farmland at this catchment area. The groundwater in this study area showed EC values ranging from 111 to 21,000 µS/cm, and the water quality types were diverse including Ca(or Na)-HCO₃, Ca(or Na)-HCO₃(Cl), Na-Cl(HCO₃), Na-Cl types. It is believed that this diversity of water quality is due to the mixing of seawater and fresh groundwater generated by infiltration of precipitation and surface water through soil and weathered part. In this study, we discussed whether this water quality diversity and the presence of saline groundwater are due to present seawater intrusion or to remnant high-saline pore water in sediments during flushing out process. For this, rain water, surface water, seawater, and groundwater were compared regarding the water quality characteristics, tritium content, oxygen/hydrogen stable isotopic composition, and ⁸⁷Sr/⁸⁶Sr ratio. The oxygen/hydrogen stable isotopic compositions indicated that water composition of saline groundwaters with large EC values are composed of a mixture of those of fresh groundwater and surface water. Also, the young groundwater estimated by tritium content has generally higher NO₃ content. All these characteristics showed that fresh groundwater and surface water have continued to affect the high-saline groundwater quality in the study area. In addition, considering the deviation pattern in the diagrams of Na/Cl ratio versus Cl content and SAR (sodium adsorption ratio) versus Cl content, in which two end members of fresh surface-ground water and seawater are assumed, it is interpreted that the groundwater in the study area is not experiencing present seawater intrusion, but flush out and retreating from ancient saline formation water.

• Journal of the Korean Geosynthetics Society
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• v.15 no.3
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• pp.57-66
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• 2016

In this study, to prevent possible collapse caused by hydraulic or mechanical instability, liquid nitrogen injection method is developed and implemented at the tip of drilling auger of steel pipe propulsion tunneling. In this study, 1/5-scale model auger and sand chamber were manufactured. The prototype diameter of steel pile (or casing) is assumed about 1,000 mm. For the frictional sandy soils and plastic weathered soils, liquid nitrogen injection methods were tested varying water contents of the soils. For the induced hydraulic instability, the ground near the drilling auger was frozen within approximately 5 minutes preventing mechanical collapse and water infiltration. Securing stability of steel pile propulsion tunneling using liquid nitrogen was much more effective for which the water content of the soil somewhat exceeds the optimum water content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.311-317
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• 2004

This study was designed to investigate the effect of Korean traditional tea materials on lead (Pb) accumulation and histological changes in Pb-administered rats. Male rats were divided into six groups: a normal, Pb, and Pb-water extract of Korean traditional tea materials (green tea: GT, persimmon leaf: PL, safflower seed: SS, Eucommia ulmoides: EU) groups. Pb (25 mg/kg BW) was orally administered once a day for 4 weeks. The extract of GT, PL, SS, and EU were administered based on 1.26 g of raw traditional tea materials/kg Bw/day. Pb contents of serum and liver were significantly higher in the Pb group than in the normal group. However the water extracts of GT, PL, SS, and EU administration lowered Pb contents of serum and liver in the Pb-administered rats, respectively. Serum Zn content was significantly higher in the Pb group than in the normal group, whereas, Cu and Fe contents were lower in the Pb group. Hepatic Ca content was significantly lower in the Pb group compared to the normal group. In the present study, water extract of Korean traditional tea materials administration effectively improved Cu and Fe contents of serum and liver. Infiltration of the local inflammation was found in Pb group, whereas water extracts of Korean traditional tea materials administration attenuated histological changes of tissues.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.543-553
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• 2013

In Korea, there have been many studies and progresses on various types of pilot scale or commercialized field scale Best Management Practices(BMP) during the last 10 years. Runoff characteristics of diffuse pollutants from different land uses are well identified and documented. However, for the coastal area connected directly with shoreline, runoff patterns and management schemes of non-point pollution were not fully studied. Recently, coastal area is emerging as a new development axis especially in west coast side of Korea such as Incheon city and Chungnam province, thus urbanized area rapidly increased but there are no buffer zones and BMP facilities to aim at preventing direct discharge of the first flush into coastal sea and beaches. In this study, parking area in Deacheon harbor, Boryeong City in Chungnam Province was selected and rainfall runoff was monitored for two year period in order to examine run-off features from which proper type of BMP suitable for coastal area is proposed. Coastal area usually has a low ground water level and consists of plain land, so that large scale BMP such as storm water retention pond and wetland requiring great excavation works is not best management plan. In addition, monitoring study shows that storm water from the paved parking area has a high salinity compared with those in storm water from the inland. High salinity is detrimental for the vegetation. Therefore, BMP employing least vegetative cover and also in terms of maintenance is a good option such as infiltration trench and porous pavement.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.9
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• pp.911-916
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• 2005

In this study, variations of water quality, sediment size and contaminant substances are analyzed at upstream and downstream in sewer systems in order to evaluate the characteristics of wastewater transformation by physico-chemical and biological reactions. The differences of DOC concentration between up and down stream showed the range of $-5.8{\sim}18.6$ from the result of continuous measurement at up and down stream. About 8.4% of DOC concentration was reduced and reduction rate was 2.3 mg/L/km. SS reduction rate was measured by 5.5 mg/L/km, 0.22 mg/L/min from upstream to downstream, which was twice than DOC reduction rate. When pollution load reduction was evaluated considering infiltration/inflow effect, DOC load was eliminated from 1,230 ka/d to 1,167 kg/d by physi-chemical and biological reaction in a sewer and 7.8% of the SS in upstream station was reduced under dry weather condition. The results showed that the characteristics of transformation process of wastewater in sewer should be considered for design and operation of wastewater treatment plant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.737-746
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• 2019

Most landslides in the country are shallow failures triggered by intense rainfall. Many researchers have revealed the possibility of predicting shallow failure through the volumetric water content (VWC). This study examined how to determine shallow failure using the gradient characteristics of the volumetric water content. For this, flume experiments were conducted using weathered granite soil. To confirm the saturation state of the surface layer under a rainfall intensity of 30 and 50mm/hr, VWC sensors were installed at depths of 10 and 20 cm on the upper, middle and lower slope. The test results showed that a shallow failure determination using VWC could be applied limitedly according to the slope degree. In addition, the effective cumulative rainfall due to the rainfall infiltration velocity is considered the main factor for the failure time. The failure prediction using the gradient of the VWC depends on the installation location and depth of the sensor. According to the experimental data, the measured value at 20 cm below the slope was most effective. Therefore, an analysis method of VWC and the method of selecting the installation location confirmed through this study can provide important data for presenting the measurement criteria using VWC in the future.

• The Journal of Internal Korean Medicine
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• v.27 no.2
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• pp.521-532
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• 2006

Backgrounds and Objectives: A major goat in asthma therapy isto reduce or prevent the inflammatory response associated with bronchial hyperresponsiveness, reversible airway obstruction and airway remodelling. Many studies have shown that eosinophilic infiltration is a prominent feathure in the pathophysiology of asthma. The importance of the Presence of eosinophils in the airways of asthmatics has long been recognized, but the mechanism by which these cells are recruited and retained in the lung are only now being elucidated Production of chemotactic cytokines by bronchial epithelial cells may contribute to the local accumulation of eosinophils in Patients with bronchial asthma. This study was designed to investigate the inhibitory effect of extraction of herbal dicoction, Gamichungsangbohatang(GMCSBHT) on eosinophil chemotactic cytokines. Material and Methods:We used water and 70% ethanol extracts of GMCSBHT and pulmonary epithelial cell lines A549(human type II -like epithelial cells). We estimated cytotoxic effects of GMCSBHT, and estimated the effects of water and 70% ethanol extracts of GMCSBHT on chemokines from prestimulated A549 cells by sandwich ELISA. Results: Chemokines of eotaxin, IL-8 were inhibited by GMCSBHT in dose-dependent manner. And ethanol extract of GMCSBHT has more inhibitory effects on eotaxin, IL-8 than hot water extract. Conculusions: These findings indicate that the supression of the expression of chemokines can be accomplished by GMCSBHT treatment, so GMCSBHT may inhibit the iuflammatory process by eosinophils in asthma.

• Journal of the Korean Geotechnical Society
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• v.28 no.11
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• pp.69-78
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• 2012

Conventional numerical analysis for rainfall-induced slope stability has been estimated by separating seepage and stress-strain behavior, respectively. Many researchers' models from commercial softwares and literatures define that partially saturated permeability is the only function of degree of saturation (or matrix suction) and then they do not consider hydraulic-mechanical characteristics for the analysis. However, in practice, the water flow processes in a deformable soil are influenced by soil skeleton movement and the pore water pressure changed due to seepage will lead to changes in stress and to deformation of a soil. The relationship between seepage and soil behavior causes a change of partially saturated permeability as well as saturated permeability with the lapse of time. Instability of partially saturated soil slopes due to infiltration would be analyzed from reduction of negative pore water pressure calculating the process of water flow based on predicted partially saturated permeability. Therefore, partially saturated permeability should be defined by the function of degree of saturation (or matric suction) and porosity. The paper presents the comparison between staggered and monolithic coupled analysis regarding seepage and stress deformation problems. As a result, the decrease in matric suction on soil slope from monolithic analysis is slower than that from staggered analysis.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.2
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• pp.88-99
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• 2007

Soil moisture is one of the essential components in determining surface hydrological processes such as infiltration, surface runoff as well as meteorological, ecological and water quality responses at watershed scale. This paper discusses soil moisture transfer processes measured at hillslope scale in the Gwangneung forest catchment to understand and provide the basis of stochastic structures of soil moisture variation. Measured soil moisture series were modelled based upon the developed univariate model platform. The modeling consists of a series of procedures: pre-treatment of data, model structure investigation, selection of candidate models, parameter estimation and diagnostic checking. The spatial distribution of model is associated with topographic characteristics of the hillslope. The upslope area computed by the multiple flow direction algorithm and the local slope are found to be effective parameters to explain the distribution of the model structure. This study enables us to identify the key factors affecting the soil moisture distribution and to ultimately construct a realistic soil moisture map in a complex landscape such as the Gwangneung Supersite.

• Journal of Korea Water Resources Association
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• v.38 no.8 s.157
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• pp.605-616
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• 2005

In this paper, runoff curve numbers (CN's) for a small forested mountainous catchment are estimated using rainfall-runoff data measured at Sulma experimental catchment every 10 minutes and a new guideline for applying the antecedent rainfall conditions (ARC's) for small mountainous watersheds in Korea is proposed. Sulma experimental catchment is a typical natural mountainous basin with $97\%$ of forested land cover and CN's are estimated to be in the range between 51 and 89 with median value of 72. The test hypothesis stating as 1-day ARC is better than 5-day ARC in determining CN's for a small mountainous watershed is shown to be acceptable. Also, linear regression equations for the estimation of CN's for small mountainous catchments are proposed. As there is no significant investigations available on CN's for small mountainous catchments, the newly proposed relationships between CN's and ARC may be used as a preliminary guideline to assign CN's for the estimation of floods from rainfall data on mountainous regions.