• Journal of Korea Soil Environment Society
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• v.2 no.1
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• pp.51-61
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• 1997

The objective of this study is to evaluate the feasibility of Pumping-and-Treatment system (PTS) for remediation of the saturated zones contaminated with NAPLs. A simulation is carried out for the removal of DNAPLs (denser-than-water non-aqueous phase liquids) and LNAPLS (lighter-than-water non-aqueous phase liquids) distributing at and below the water table. In the study, LNAPL and DNAPL are assumed to be n-hexane and 1,1-dichloroacetone, respectively. The model system studied consists of four heterogeneous soil layers with different permeabilities. Groundwater flows through the bottom layer and a pumping well is located under the initial water table. The time-driven deformation of the water table and removal efficiency of contaminants are estimated after vacuum application to the inlet of the well. In the calculation, FVM (Finite Volumetric Method) with SIMPLEC algorithm is applied. Results show that removal efficiencies of both DNAPL and LNAPL are negligible for the first 5 days after the PTS operation. However, when the cone-shape water table is formed around the inlet of the pumping well, the rapid removal rate is obtained since NAPLs migrate rapidly through the curvature of the water table. The removal efficiency of DNAPL is estimated to be higher than that of LNAPL due to the gravity. The results also show that the fluctuation or cone-shaped depression of the water table enhances the removal efficiency of NAPLs in saturated zones. The simulation results could provide a basis of the PTS design for the removal of NAPLs in saturated zones.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.213-219
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• 2006

The Yongjang mine is located in Masan City, Gyeongsangnamdo, which consists of a black shale possessing quartzite veins with othercompositions such as gold, silver, and sublimated sulfur. The average width of the veins is $9{\sim}17cm$ and the average degrees of the gold and silver are 3.6 g/t and 113.6 g/t respectively. A regional and a detailed scale electrical resistivity surveys are conducted to determine the existence of the mineralization zones and the linear structures in the study area. In addition, surveys of a several different array methods are conducted such as dipole-dipole array in the surface and borehole-to-surface array, surface-to-borehole array, and dipole-dipole array in the borehole. The method of element division can be applied to the region in which the borehole is curved, inclined or the distance between the electrodes is shorter than that of nodal points, because the coordinate of each electrode cannot be assigned directly to the nodal point if several electrodes are in an element. Yongjang vein is extended longer under the subsurface than on the surface in the images reconstructed from the 3D inversion. Therefore, it is recognized that the 3-D interpretation of the electrical resistivity survey is a very useful method to figure out the existence of strike and extension direction because the mineralization zones and the linear structures are shown in each depth.

• Economic and Environmental Geology
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• v.2 no.1
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• pp.1-12
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• 1969

In the Sangdong Mine area, Taebaegsan series (Pre-Cambrian) and Chosun System (Cambro-ordovician) are widely distributed. The Chosun System consists of Yangdug Series (Jangsan Quartzite and Myobong Slate) and The Great Limestone Series (Pungchon Limestone, Shesong Shale, Hwajeol Formation and Dongjeom Quartzite). The mineralized zone containing the main ore body of the Sangdong Mine was developed in the Myobong Slate formation. The result of the field and microscopic study on the mineral paragenesis and it's wall rock alteration in the tungsten ore deposit shows the following features. The orogenic movements of the Post-Chosun System in the Hambaeg Geosyncline are closely related to the tungsten ore deposition in the area, the ore minerals are composed mainly of scheelite, powelite molybdenite and sulfide minerals, and gangue minerals are hornblende, diopside, garnet, quartz, phlogopite, tremolite, biotite, muscovite, fluorite, etc., main ore body was enriched by scheelite bearing quartz vein filling into interstices of formerly mineralized zones, and the minor faults, faults of N $60^{\circ}-70^{\circ}W$, $45^{\circ}-60^{\circ}NE$ and joints, which were formed at the end of the mineralization and the slate. Country rock of the ore body was altered into the following several zones from the outside to the inside; lowgrade recrystalline aureole, silicified sericite zone, and diopside-hornblende zone. Under the microscopic observation of 195 samples taken from throughout ore body can be classified into 10 different groups by their mineral paragenesis as shown in table 2. The garnet-diopside group is primary skarn and it shows gradational change to the groups of later stage by the successive processes of metasomatism. From the stage of quartz-bearing group, the dissemination of scheelite is seen. The crystallization of scheelite in the bed started with the quartz deposition and continued to the last stage when quartz vein intruded into the main ore body. In the field and the under ground investigation a durable limestone bed in thickeness about 20 meters and their remnants in ore body are observed and under microscope calcite remnants are recognized. Hence it is posturated that the ore material moved up through the faults, shear zones or feather cracks and was assimilated with the interbeded limestone, after that the body was affected by the successive differentiated ore solution by gradational increasing in $SiO_2$, $K_2O$ and $H_2O$. Evidently this ore deposit shows the features resulted from pyrometasomatic processes.

• Economic and Environmental Geology
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• v.28 no.4
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• pp.395-404
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• 1995

The geologic structure of the Cheju volcanic island has been investigated by analyzing the gravity and magnetic data. Bouguer gravity map shows apparent circular low anomalies at the central volacanic edifice, and the maximum difference of the anomaly values on the island appears to be 30 mgal. The subsurface structure of the island is modeled by three-dimensional depth inversion of gravity data by assuming the model consists of a stacked grid of rectangular prisms of volcanic rocks bounded below by basement rocks. The gravity modeling reveals that the interface between upper volvanic rocks and underlying basement warps downward under Mt. Halla with the maximum depth of 5 km. Magnetic data involve aeromagnetic and surface magnetic survey data. Both magnetic anomaly maps show characteristic features which resemble the typical pattern of total magnetic anomalies caused by a magnetic body magnetized in the direction of the geomagnetic field in the middle latitude region, though details of two maps are somewhat different. The reduced-to-pole magnetic anomaly maps reveal that main magnetic sources in the island are rift zones and the Halla volcanic edifice. The apparent magnetic boundaries inferred by the method of Cordell and Grauch (1985) are relatively well matched with known geologic boundaries such as that of Pyosunri basalt and Sihungri basalt which form the latest erupted masses. Inversion of aeromagnetic data was conducted with two variables: depth and susceptibility. The inversion results show high susceptibility bodies in rift zones along the long axis of the island, and at the central volcano. Depths to the basement are 1.5~3 km under the major axis, 1~1.5 km under the lava plateau and culminates at about 5 km under Mt. Halla. The prominent anomalies showing N-S trending appear in the eastern part of both gravity and magnetic maps. It is speculated that this trend may be associated with an undefined fault developed across the rift zones.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1123-1130
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• 2013

This paper aims to estimate work zone base capacity by the number of lanes for urban freeway. To do this, data were collected from the field survey and the database system maintained by traffic control center, and analyzed with four different methods such as the average maximum observation flow rate, headway, regression analysis, and parameter inspection. The work zone base capacity for urban freeway is estimated based on the average maximum observation flow rate and headway method, which are more reliable methods compared to others. The average capacity is 1,650pcphpl when the design speed is 80km/h. The capacity of four lanes one-way work zones was about 1,700pcphpl, while one of 2 lanes one-way work zones was about 1,600pcphpl. The capacity reduction rates for each are 0.15 and 0.2, respectively. The smaller the number of lane is, the more base capacity is reduced. For verification of results, we estimate the capacity by simulation analysis using PARAMICS, and compare with analytical results by a statistical method. This research can be used for efficient and systemic management of work zone in the urban freeway.

• Journal of Cadastre & Land InformatiX
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• v.47 no.2
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• pp.5-18
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• 2017

The AMOEBA approach in this study supplements the Hotspot method that had not been fully capable of dealing with the ecotone issues in designating the Development Impact Fee (DIF) zones as had been seen in the preceding study by Kim and Choei (2017). The AMOEBA procedure shares the common Getis-Ord statistic with the Hotspot technique but is more adequate to figure out the ecotones. For the comparative purpose, simulations are run by both methods for a series of different scenarios in terms of analytic spatial units (here, the square grids) from 100m up to 400m; and the zonal outcomes by both methods are compared using a set of evaluative indicators. In terms of the numerical scores, the performances by the two methods are much comparable except that the former is slightly superior with respect to the avoidance of the oversized spread of the selected zones whereas so is the latter with respect to the ease of infrastructure installation. It remains yet to be investigated by the extended studies that include in-depth field surveys to figure out the causes as well as the meanings of such differences in zonal determinations.

• The Journal of Engineering Geology
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• v.29 no.3
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• pp.223-236
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• 2019

Resistivity surveys can identify the distribution of geological units and structures (including fragmented fault zones), the extent of weathered and modified geological strata, and the characteristics of groundwater. This study aims to analyze the underground sedimentary layers and geological structures near the Nari and Albong Basins of Ulleung-do, Korea, focusing on six survey lines to identify the spatial trends in subsurface resistivity. A modified dipole array method (D method) was employed, combining resistivity results obtained by existing dipole array methods (A and C methods). The modified method provides optimal analysis of the cross-section of underground resistivity, and shows a clear boundary between a low-resistivity zone (${\leq}500{\Omega}{\cdot}m$) of sedimentary layers and weak zones, and a high-resistivity zone (${\geq}5,000{\Omega}{\cdot}m$) of volcanic rock (trachyandesite). The estimated average thickness of the sedimentary layers is 50~100 m for the Albong Basin and 100~200 m for the Nari Basin. An anomaly zone, different from the weak zone in the bedrock, is identified as a caldera fault, and the low-resistivity zone extends from the surface down to the lowest survey depths.

• The Korean Journal of Nuclear Medicine
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• v.35 no.3
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• pp.131-141
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• 2001

Purpose: We evaluated the sensitivity of the F-18 FDG PET by visual assessment and statistical parametric mapping (SPM) analysis for the localization of the epileptogenic zones in frontal lobe epilepsy. Materials and Methods: Twenty-four patients with frontal lobe epilepsy were examined. All patients exhibited improvements after surgical resection (Engel class I or II). Upon pathological examination, 18 patients revealed cortical dysplasia, 4 patients revealed tumor, and 2 patients revealed cortical scar. The hypometabolic lesions were found in F-18 FDG PET by visual assessment and SPM analysis. On SPM analysis, cutoff threshold was changed. Results: MRI showed structural lesions in 12 patients and normal results in the remaining 12. F-18 FDG PET correctly localized epileptogenic zones in 13 patients (54%) by visual assessment. Sensitivity of F-18 FDG PET in MR-negative patients (50%) was similar to that in MR-positive patients (67%). On SPM analysis, sensitivity decreased according to the decrease of p value. Using uncorrected p value of 0.05 as threshold, sensitivity of SPM analysis was 53%, which was not statistically different from that of visual assessment. Conclusion: F-18 FDG PET was sensitive in finding epileptogenic zones by revealing hypometabolic areas even in MR-negative patients with frontal lobe epilepsy as well as in MR-positive patients. SPM analysis showed comparable sensitivity to visual assessment and could be used as an aid in the diagnosis of epileptogenic zones in frontal lobe epilepsy.

• Journal of Ecology and Environment
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• v.36 no.2
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• pp.131-140
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• 2013

In Korea, many paddy fields in mountainous area have been abandoned because of their low accessibility and rice price and the abandoned paddy terraces have changed into natural lentic wetlands. To understand the relationship between characteristics of environmental conditions and early development of plant community in abandoned paddy terraces, we investigated at four well-maintained abandoned paddy terraces in 3 different climatic zones in Korea. Soil texture of abandoned paddy terraces was mostly kinds of loam and electric conductivity of soil was also similar among abandoned paddy terraces. On the other hand, contents of nitrogen, phosphorus, potassium, sodium, magnesium, and calcium in soil were relatively low and significantly different among abandoned paddy terraces. Water depth was different within sites and inter-sites. Although environmental conditions including climate, soil condition and water depth were different among abandoned paddy terraces, the compositions of plant communities were relatively similar in all abandoned paddy terraces. 55 dominant taxa out of 141 recorded species were commonly recorded over sites and they were mostly perennial obligate wetland plants and facultative wetland plants. 8 taxa out of 55 dominant taxa occurred at all abandoned paddy terraces with over 10% coverage. Several site-specific species occurred at site, which have some area with deep water level. This result indicates that early development of plant community in abandoned paddy terraces of similar water regime is similar in the entire area of Korea even though environmental conditions such as climate, biogeographic history and soil are different.

• Journal of dental hygiene science
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• v.18 no.1
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• pp.18-23
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• 2018

Propolis has been used as a natural remedy in folk medicine worldwide. The antibacterial, antiviral, antifungal, and antiprotozoal aspects of its antimicrobial properties have been widely investigated. However, few studies focused on its applications in dentistry. Many dental diseases are related to various microorganisms in the oral cavity. In this study, we assessed the antimicrobial activity of Korean propolis extract, collected from 6 different regions, on oral pathogenic microorganisms. The propolis samples, collected from 6 different regions (P1: Uijeongbu, P2: Ansan, P3: Hongcheon, P4: Iksan, P5: Gwangju, and P6: Sangju), were dissolved in ethanol at two different concentrations (10 and 50 mg/ml). Three oral bacteria (Streptococcus mutans, Staphylococcus aureus, and Enterococcus faecalis) and one fungus (Candida albicans) were activated in general broth for 24 hours. Microorganisms were diluted and spread onto agar plates, onto which sterilized 6 mm filter papers with or without each propolis sample were placed. After 24 hours of incubation, clear zones of inhibition were observed. All tests were performed in triplicate. The propolis samples showed significant antibacterial and antifungal activity on oral pathogenic microorganisms; in addition, low-concentration groups showed outstanding antimicrobial efficacy on the 4 different microorganisms. Among the samples, P6 had significantly higher antibacterial activity than that of the others against three different bacteria. In particular, a high concentration of P6 showed a significant antifungal effect. In conclusion, we confirmed that Korean propolis has an inhibitory effect on oral pathogenic bacteria and fungi. Therefore, we suggest the possibility of developing oral medicine and oral care products based on Korean propolis.