• 한국지반신소재학회논문집
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• 제10권2호
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• pp.29-34
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• 2011

본 연구에서는 유류나 각종 비수용성 오염물질(DNAPL)로 오염된 지반에 인공동결공법을 이용한 차수벽을 형성하고 지하수의 이동으로 인한 오염물질의 확산 방지 효과를 확인하기 위한 초기연구로 인공동결공법을 통한 동결차수벽을 형성하기 위하여 모형실험을 수행하였다. 동결차수벽 형성의 확인을 위하여 실험조건에 따른 동결범위와 동결토의 강도를 분석하였다. 동결범위를 확인하기 위한 실험조건은 포화도가 80%, 90%인 표현을 실트를 대상으로 하였다. 또한, 동결토의 강도특성은 다짐도와 포화도를 변경하여 동결을 실시하였고, 일축압축강도 실험을 통하여 확인하였다.

• Environmental Engineering Research
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• 제15권4호
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• pp.225-230
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• 2010

In order to treat soil contaminated with high percentages of water and petroleum, the combined microwave and thermal desorption process was studied, which was composed of the consecutive connection of two pre-treatment processes. For the thickness of the contaminated soil layer on the transfer conveyor belt, the optimal total petroleum hydrocarbon (TPH) removal rate was studied with respect to the duration of microwave exposure in the consecutive process combined with thermal desorption. The TPH removal rate when the contaminated soil layer thickness was 1 cm at 6 kW of microwave power was 80%. The removals rates for 2 and 3 cm soil layer thicknesses were both 70%. Under identical experimental conditions, the TPH removal rate for the microwave pre-treatment, when considering the soil particle size, was over 70%. The lowest TPH removal rate was achieved with a particle diameter of 2.35 mm. For contaminated soil with 30% water content, 6 kW and a thermal desorption temperature of $600^{\circ}C$ were the optimal operational conditions for the removal of THP. However, considering the fuel consumption cost, 4 kW and a thermal desorption temperature of $300^{\circ}C$ would be the most economic conditions.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.257-266
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• 1999

This paper presents a method of seismic analysis for a cylindrical liquid storage structure on/in horizontally layered half.space considering the effects of the interior fluid and exterior soil medium in the frequency domain. To capture the essence of fluid-structure-soil interaction effects effectively, a mixed finite element with two-field (u, p) approximation is employed to model the compressive inviscid fluid, while the structure and soil medium are presented by the 3-D axisymmetric finite elements and dynamic infinite elements. The present FE-based method can be applied to the system with complex geometry of fluid region as well as with inhomogeneous near-field soil medium, since it can directly model both the fluid and the soil. For the purpose of verification, dominant peak frequencies in transfer functions for horizontal motions of cylindrical fluid storage tanks with rigid massless foundation on a homogeneous viscoelastic half.space are compared with those by two different added mass approaches for the fluid motion. The comparison indicates that the Present FE-based methodology gives accurate solution for the fluid-structure-soil interaction problem. Finally, as a demonstration of versatility of the present study, a seismic analysis for a real-scale LNG storage tank embedded in layered half.space is carried out, and its member forces along the height of the structure are compared with those by an added mass approach developed by the present writers.

• 한국지반공학회논문집
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• 제19권3호
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• pp.45-51
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• 2003

복합기초의 한 형식인 소일시멘트 말뚝의 거동 특성을 컴퓨터 해석을 통하여 연구하였다. 연직하중을 받는 소일시멘트말뚝의 거동 특성을 ABAQUS라는 상용 프로그램을 사용하여 조사하였으며 해석조건은 지반물성치, 말뚝의 길이, 치환율, 강성비, 하중 조건 등을 달리하여 실시하였다. 해석 결과는 하중의 전이 및 침하특성 뿐만 아니라 효과적인 말뚝길이와 말뚝 및 지반의 하중 분배에 관하여서도 유용하게 쓰일 수 있음이 판명되었다. 또한 복합기초를 설계할 때 강성비, 치환율이 설계에 가장 큰 영향을 미치는 인자로 나타났다.

• 한국토양비료학회지
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• 제42권Spc호
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• pp.33-39
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• 2009

논토양에서 지속가능한 농업생산 및 환경보호를 위한 양분관리는 토양의 화학반응들에 따른 지표들을 활용하는 것이다. 이 연구는 동일비료 영년시험 결과와 2000년부터 2002년까지 수행된 논토양 유형별 질소수준 시험 결과 등을 토대로 하여, 논토양의 화학작용 및 이와 관련된 양분공급력 지표들을 조사하였다. 논토양의 화학작용은 영양성분의 흡탈착 및 유기물질의 분해를 통한 수소, 전자, 이산화탄소의 생성작용과 이들 물질에 의한 화학작용 등으로 구성되었다. 이러한 토양의 화학작용을 고려한 양분공급력 지표들은 다음과 같았다. 질소의 공급력 지표는 토양유기물 또는 토양단백질이었으며, 인산의 공급력 지표는 유효인산함량이었고, 칼륨의 공급력 지표는 양이온교환용량과 치환성 양이온함량이었다. 한국에서는 논토양의 시비 추천식은 이러한 양분공급력 지표들을 사용하여 설정한 것으로 나타나 환경을 보전하면서 농업생산을 지속적으로 유지할 수 있는 것으로 판단된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.963-970
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• 2010

In this study, a series of thermal numerical analysis was conducted through the ground condition and the length and shape of the energy pile. In order to investigate the effect of the thermal properties of ground condition, grout and pile type on heat transfer efficiency in the U-type heat exchanger in energy pile, thermal numerical analysis was done by using ABAQUS. ABAQUS, a finite element analyzing program, was employed to evaluate the temperature distribution on the cross section of energy pile system incorporating HDPE - grout - pile - Ground condition which consists of clay, sand, rock type soil and ground water.

• Geomechanics and Engineering
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• 제7권2호
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• pp.149-164
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• 2014

One of the most advanced classes of techniques for ground response analysis is based on the use of Transfer Functions. They represent the ratio of Fourier spectrum of amplitude motion at the free surface to the corresponding spectrum of the bedrock motion and they are applied in frequency domain usually by FFT method. However, Fourier spectrum only shows the dominant frequency in each time step and is unable to represent all frequency contents in every time step and this drawback leads to inaccurate results. In this research, this process is optimized by decomposing the input motion into different frequency sub-bands using Wavelet Multi-level Decomposition. Each component is then processed with transfer Function relating to the corresponding component frequency. Taking inverse FFT from all components, the ground motion can be recovered by summing up the results. The nonlinear behavior is approximated using an iterative procedure with nonlinear soil properties. The results of this procedure show better accuracy with respect to field observations than does the Conventional method. The proposed method can also be applied to other engineering disciplines with similar procedure.

• 한국버섯학회지
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• 제3권4호
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• pp.145-153
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• 2005

미생물을 이용한 중금속 오염지의 생물적 개량연구를 위하여 구리, 납 등 중금속 오염지인 은성 폐광과 도곡 폐광지역에서 야생버섯을 수집 동정하고 중금속 함량을 분석한 결과 Laccaria laccata가 가장 높게 나타났으며 토양 내 중금속함량이 높을수록 버섯 내 중금속 농도도 높았다. 그러나, 전이계수를 이용하여 버섯 자실체의 중금속 이행률을 알아본 결과, Amanita volvata가 카드뮴과 비소의 이행률이 가장 높았으며, 구리의 이행률은 Agaricus praesquamosus가 다른 버섯에 비해 월등히 높은 수치를 나타냈다. 납은 Mycena pura, 아연은 Marasmius pulcherripes, 니켈은 Laccaria laccata, 크롬은 Collybia confluens로 나타났다. 중금속 오염지와 비오염지인 치악산 지역에서의 담자균의 발생 분포를 비교한 결과, Russula와 Collybia 속은 비오염지와 오염지역 모두에서 발생되었으며 Leucocoprinus, Coprinus, Suillus, Lepiost, Gyroporus. Lepista, Microstoma, Stropharia, Agrocybe 속은 오염지에서만 발생되었다. 이상의 결과, Laccaria laccata 등 일부 담자균은 중금속 오염지 저감에 이용할 가능성이 있으며 이를 위한 많은 연구가 기대된다.

• 한국환경과학회지
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• 제16권2호
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• pp.233-239
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• 2007

In the coastal wetland the mud is consist of fine particles, which means that it is characterized by small gap, and heat transfer is obstructed since moisture is found between the gaps. The relationship between net radiation ($R_N$) and soil heat flux($H_G$) shows a counterclockwise hysteresis cycle, which refer to a time lag behind in the maximal soil heat fluxes. The albedo is independent of seasonal variation of the vegetation canopy which plays very important roles to store and control the heat in the atmospheric surface layer.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.319-322
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• 1999

Land surface hydrological conditions have been considered to play an important role in the global and regional climate variability. Especially, snow, soil moisture, surface temperature, vegetation and rain are the key parameters which should be observed in the global scale. In this paper, new algorithms for these land surface hydrological parameters have been developed by introducing frequency and polarization dependencies of these parameters in the microwave radiative-transfer equations. The algorithms were applied to the TRMM Microwave Radiometer. (TMI) and validated by using the ground data obtained in the Tibetan Plateau. The estimated snow, soil moisture, surface temperature, water content of vegetation and rain patterns corresponded reasonably to the observed ones.