• Korean Journal of Heritage: History & Science
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• v.47 no.2
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• pp.32-45
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• 2014

The aim of this study is to raise a cognition and necessity of effective geoheritage education for pre-service teachers. We conducted a survey research of 190 elementary and secondary pre-service teachers in Chung-buk province, 2013. The survey showed that pre-service teachers did not recognize and explain geoheritatges well due to lack of education even though they have heard about 'geoheritages' through broadcast media. Although most pre-service teachers were not trained for geoheritage courses, some of them were educated from their elementary and middle school teachers. However, even the trained pre-service teachers have insufficient cognition for geoheritages, either. Some of pre-service teachers recognized the significance of geoheritages and responded to a necessity of geoheritage education. The pre-service teachers recognized that education for geoheritages is not included in present elementary and secondary curriculum, even though education of geoheritages by teachers at school would be the most effective approach. Furthermore, the pre-service teachers answered that elementary school curriculum should raise much curiosity and provide effective learning for geoheritage education even though negative views are present such that students may have to spend considerable time for geoheritage education. Finally, the pre-service teachers expect to experience with field activities for geoheritage education as a present curriculum, and responded that they would prefer video aids for education provided from professional geoheritage organization. As a result of this investigation we provide strategy for introducing to Pre-service teachers about value and preciousness of geoheritage.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.219-224
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• 2002

충북 청원군 미원면 금관-원룡리 일대를 따라 발달된 화전리층(상층)과 구룡산층 분포지역에서, 기반암에 따른 지하수 및 지표수의 수질특성의 차이를 규명하고자 하였다. 화전리층(상층)지역의 경우 Ca-(HCO$_3$+.CO$_3$) 유형을, 구룡산층 지역의 경우 (Ca,Mg)-SO$_4$ 및 (Ca,Mg)-HCO$_3$ 유형을 보였다. 지하수의 경우, 화전리층(상층) 지역은 주고 탄산염광물의 풍화에 의해, 구룡산층 지역은 주로 규산염광물의 풍화에 의해 수질특성이 결정됨을 보였으며, 이러한 차이는 통계분석 방법으로 확인할 수 있었다. 지표수의 경우, 한 지점을 제외하고는 대부분이 암반 기원으로 도시되어 기반암의 영향이 수질특성을 좌우하고 있음을 보였다. 본 연구의 결과는, 지하수ㆍ지표수 각각의 수질 특성이 지역적인 기반암 종류에 따름을 확인시켜주는 바, 국가적인 수질관리정책은 지역적인 지질매체의 차이를 고려하면서 수립 ㆍ시행되어야 함을 보여준다.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2002.08a
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• pp.308-315
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• 2002

해양구조물 설치(Offshore Engineering)에 대한 수요가 급증함에 따라 보다 정확한 설계와 시공을 위한 해저지형 및 지질환경에 대한 탐사(Geophysical Survey)수요가 급격히 증가하고 있다. 전자기파의 감쇄가 심한 해수로 덮여 있는 해저에 대한원격탐사 매체로는 SONAR(SOund Navigation And Ranging)시스템이 일반적으로 이용되고 있다. (중략)

• Economic and Environmental Geology
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• v.38 no.5 s.174
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• pp.525-534
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• 2005

Adsorption experiments for As(V) and As(III) onto the surfaces of aerobic Pseudomonas aeruginosa, which can be readily isolated from natural media, were conducted under nutrient-absent conditions. While a small amount of As(III) was adsorbed on the bacterial cell surfaces, As(V) was not effectively removed from the solution through adsorption. The result was likely due to the electrostatic repulsion between anionic compounds of aqueous As(V) and cell surfaces of f aeruginosa. However, the bacteria forming biofilm reduced a large amount of aqueous As(V) to As(III), which indicated that microorganisms in most oligotrophic, natural geologic settings can mediate the behavior of aqueous As. Biobarriers designed to remove the various heavy metals in contaminant plume may practically lead to the enhancement of toxicity and mobility of As.

• Economic and Environmental Geology
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• v.50 no.5
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• pp.401-414
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• 2017

To prevent the damages from earthquakes, various researches have been conducted around the world focusing on earthquake prediction and forecasting for several decades. Among various precursory phenomena, changes in groundwater level and quality are considered to be reliable for estimating the time of earthquake occurrence and its magnitude. In effects, some countries impacted by frequent earthquakes have established and operated the groundwater monitoring network for earthquake surveillance and prediction. In Korea, recently researches have begun for using groundwater monitoring techniques for earthquake prediction. In this paper, the groundwater monitoring networks of China, Japan, and the United States were reviewed focusing on the facilities and results of researches to deduce the tasks for earthquake prediction researches using groundwater monitoring techniques in Korea. In results, research needs are suggested in the implementation of groundwater monitoring networks for specifically earthquake surveillance with the real-time monitoring and the measures to quantify the degrees of abnormal changes in the relationship of distance from the earthquake epicenter.

• The Journal of Engineering Geology
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• v.19 no.2
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• pp.205-215
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• 2009

The conventional numerical models to analyze flow in subsurface porous media under the transient state usually generate numerical oscillation and unstability due to local flux domain for critical cases such as infiltration into initially dry soil during rainfall period. In this case, it is required refined mesh and small time step, but it decrease efficiency of computation. In this study, numerical unstability in discontinuity domain is removed by applying particle tracking algorithm to simulate unsteady subsurface flow with inflow boundary condition. Finally the hybrid LE FEM improving numerical stability is proposed. The hypothetical domains with unsteady uniform and nonuniform flow field were used to demonstrated algorithm verification. In comparison with analytic solution, we obtained reasonable results and conducted simulation of hypothetical 3-D recharge/pumping area. The proposed algorithm can simulate saturated/unsaturated porous media with more practical problems and will greatly contribute to accuracy and stability of numerical computation.

• Economic and Environmental Geology
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• v.54 no.1
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• pp.105-115
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• 2021

The geological CO2 sequestration in underground geological formation such as deep saline aquifers and depleted hydrocarbon reservoirs is one of the most promising options for reducing the atmospheric CO2 emissions. The process in geological CO2 sequestration involves injection of supercritical CO2 (scCO2) into porous media saturated with pore water and initiates CO2 flooding with immiscible displacement. The CO2 migration and distribution, and, consequently, the displacement efficiency is governed by the interaction of fluids. Especially, the viscous force and capillary force are controlled by geological formation conditions and injection conditions. This study aimed to estimate the effects of surfactant on interfacial tension between the immiscible fluids, scCO2 and porewater, under high pressure and high temperature conditions by using a pair of proxy fluids under standard conditions through pendant drop method. It also aimed to observe migration and distribution patterns of the immiscible fluids and estimate the effects of surfactant concentrations on the displacement efficiency of scCO2. Micromodel experiments were conducted by applying n-hexane and deionized water as proxy fluids for scCO2 and porewater. In order to quantitatively analyze the immiscible displacement phenomena by n-hexane injection in pore network, the images of migration and distribution pattern of the two fluids are acquired through a imaging system. The experimental results revealed that the addition of surfactants sharply reduces the interfacial tension between hexane and deionized water at low concentrations and approaches a constant value as the concentration increases. Also it was found that, by directly affecting the flow path of the flooding fluid at the pore scale in the porous medium, the surfactant showed the identical effect on the displacement efficiency of n-hexane at equilibrium state. The experimental observation results could provide important fundamental information on immiscible displacement of fluids in porous media and suggest the potential to improve the displacement efficiency of scCO2 by using surfactants.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.376-376
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• 2023

전 세계적으로 중요한 담수 자원인 지하수의 미세플라스틱 오염에 대한 우려가 커지고 있다. 지하수 환경에서 미세플라스틱의 오염을 예측하고 평가하기 위해 대수층 내 현장 실태조사가 수행 중에 있으며, 실험실 규모의 컬럼 실험을 통해 지하수에서 미세플라스틱 이동 메커니즘을 조사하는 연구들이 수행되고 있다. 이러한 연구들은 많은 개수의 분석 시료를 동반하며, 환경 중 미세플라스틱 정량분석을 위해서 고가의 분석기기(라만분광기, 푸리에 변환 적외선(FTIR) 분광기, 열분해 가스크로마토그래피 질량분석기)를 사용하여 플라스틱의 종류를 판별하고 개수를 측정하고 있다. 또한, 컬럼 실험을 수행한 대부분의 선행 연구에서는 미세플라스틱 정량분석을 위해 탁도 분석, 분광광도계를 이용한 흡광도 분석, 현미경을 이용한 계수 방법 등을 이용하여 고가의 분석기기를 사용하지 않고 연구를 수행하였다. 하지만, 이러한 방법들은 유체 속 다른 물질이 포함되어있을 경우에 민감하고 농도를 비율 혹은 개수로 표현하기 때문에 질량 측면에서 미세플라스틱의 농도를 과소·과대 평가할 수 있다. 특히, 현미경을 이용한 계수 방법의 경우에는 분석에 많은 시간이 소요된다는 단점이 있다. 위에 언급한 다양한 분석법들의 단점들을 보완하기 위하여, 본 연구에서는 대수층 내 미세플라스틱 이동 특성을 규명하기 위한 실내 실험에 사용될 수 있는 형광이미지 기반의 미세플라스틱 정량분석법을 개발하였다. Nile Red 형광염료를 이용하여 미세플라스틱을 염색하고 사진을 촬영하여 미세플라스틱 시료의 질량과 미세플라스틱 형광이미지의 형광강도 간 상관관계를 분석하였다. 또한, Nile Red로 염색된 미세플라스틱 입자의 수중 노출 테스트를 진행하여, 실내 대수층 모의실험 시 미세플라스틱 질량을 정량화할 수 있는 적용 가능성을 평가하였다. 상관 분석 결과, 미세플라스틱 질량과 이미지의 형광강도는 높은 상관관계를 보였으며, 수중 노출 실험 전과 후의 미세플라스틱 입자의 형광강도 차이는 미미한 것으로 나타났다. 이러한 연구결과를 통해 본 연구에서 개발된 미세플라스틱 정량분석 방법이 포화 다공성 매체로 구성된 컬럼실험 시 유출수의 미세플라스틱 질량 추정에 유용하게 사용될 것으로 생각되며, 대수층 내 미세플라스틱의 이동 특성 규명 연구에 많은 도움이 될 것으로 기대된다.

• Journal of the Korean Geotechnical Society
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• v.18 no.6
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• pp.5-16
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• 2002

A hydrogeomechanical numerical model is presented to evaluate rainfall impacts on groundwater flow in slopes and slope stability. This numerical model is developed based on the fully coupled poroelastic governing equations for groundwater flow in deforming variably saturated geologic media and the Galerkin finite element method. A series of numerical experiments using the model developed are then applied to an unsaturated slope under various rainfall rates. The numerical simulation results show that the overall hydromechanical slope stability deteriorates, and the potential failure nay initiate from the slope toe and propagate toward the slope crest as the rainfall rate increases. From the viewpoint of hydrogeology, the pressure head and hence the total hydraulic head increase as the rainfall rate increases. As a result, the groundwater table rises, the unsaturated zone reduces, the seepage face expands from the slope toe toward the slope crest, and the groundwater flow velocity increases along the seepage face. From the viewpoint of geomechanics, the horizontal displacement increases, and the vertical displacement decreases toward the slope toe as the rainfall rate increases. This may result from the buoyancy effect associated with the groundwater table rise as the rainfall rate increases. As a result, the overall deformation intensifies toward the slope toe, and the unstable zone, in which the factor of safety against shear failure is less than 1, becomes thicker near the slope toe and propagates from the slope toe toward the slope crest. The numerical simulation results also suggest that the potential tension failure is likely to occur within the slope between the potential shear failure surface and the ground surface.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.330-333
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• 2004

국내 폐금속광산 일대에서 비소 및 중금속의 발암 및 비발암 위해성을 근거로 복원 기준치를 설정하였다. 폐금속광산일대의 주요한 노출 경로는 부지내 폐광석과 광미로부터 직접적인 오염물 흡입과 지하수를 통한 부지내 및 외 섭취의 경로로 구분된다. 지하수의 오염원은 폐광석과 광미 침출로부터의 오염과 갱구 유출로부터의 오염 및 지질매체 자체에 의한 오염이 설정되었다. 높은 오염 수준에 대해서 높은 오염성분감소비와 폐광산일대의 다양한 배경농도로부터 복원기준치를 설정 했을때, 토양 및 지하수의 복원기준치는 비소 위해도의 영향이 매우 큰 것으로 평가되었다. 비소의 높은 독성은 복원 기준치를 매우 낮게 형성했고, 위해도가 낮은 아연과 카드늄은 높게 설정되었다. 궁극적으로 오염성분 감소비에 따른 복원기준치 설정은 오염성분의 노출 경로 차단이 복원 목표치를 현실화시킬 수 있음을 보여주었다.