• Environmental Analysis Health and Toxicology
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• 제16권3호
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• pp.121-126
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• 2001

Analytical method of benzophenone (BP) in sediment and soil was developed by gas chromatography/mass selective detector/selected ion monitoring (GC/MSD/SIM). The ultrasonic extraction of US EPA (method 3550B) method and liquid-liquid extraction for sediment and soil samples were used for the analysis of BP from sediment and soil. BP was extracted with n-hexane. Organic layer was washed with 5% sodium chloride solution. 1∼2 l of the concentrated solution of organic layer was applied to GC/MSD. The retention time of BP peak was 11.10 min. Recovery (％) of BP by ultrasonication from sediment and soil samples was 96.0∼100.6％ and 40.0∼83.0％, respectively. Recovery of BP by liquid-liquid extraction was 51∼59％ in soil samples. The detection limit of BP in sediment and soil samples were determined to 0.1 ng/g.

• 분석과학
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• 제28권5호
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• pp.317-322
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• 2015

토양 중 음이온 바이오사이드인 chlorite, chlorate, cyanuric acid와 sodium dodecylbenzenesulfonate (Na-DBS)의 liquid chromatography-tandem mass spectrometry (LC-MS/MS) 동시 분석방법을 개발하였다. Chlorite와 chlorate는 물로 추출하였으며, cyanuric acid와 Na-DBS는 0.25 mM ammonium formate를 함유한 20 mM formic acid와 acetonitrile (1:1) 이동상을 이용하여 추출하였다. 추출물은 필터 후 직접 LC-MS/MS로 주입하였다. 분석물질이 검출되지 않는 토양에 각 성분들을 첨가한 후 정도관리를 실시한 결과 검출한계는 chlorite 0.04 mg/kg, chlorate 0.04 mg/kg, cyanuric acid 0.27 mg/kg 그리고 Na-DBS의 경우는 0.05 mg/kg 이었다. 이 방법을 사용하여 우리나라 AI로 소독제를 많이 사용한 장소 40개 지역과 사용하지 않은 지역 10개 대조 지역의 토양을 분석한 결과 대조지역을 포함한 모든 조사지역에서 네 가지 음이온 모두 검출되지 않았다.

• 분석과학
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• 제22권4호
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• pp.293-301
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• 2009

휴대용 형광 분석기의 개발을 위한 사전 기초연구로서 bench-top ED-XRF 및 휴대용 XRF를 이용하여 토양 시료 중의 Cr, As, Se, Hg, Pb, Cd 등 6종의 유해금속 성분들을 비교 분석하였다. 유해금속 원소를 0~1500 mg/kg 농도 범위로 오염시킨 토양 인증표준물질을 구입하여 XRF 분석의 중요 인자인 X-선 튜브 전압 및 측정 시간 등에 따른 최적 분석조건을 확립하고, 각각의 유해 중금속에 대한 검량선을 작성하였다. 유해금속 원소가 포함된 토양 인증표준물질 외에 7종의 다른 토양 시료 중의 유해금속 원소에 대해서도 empirical 법 및 fundamental parameter 법으로 정량분석하고 그 결과를 비교 분석하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.1009-1019
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• 2009

Soil nailing method is widely used in reinforcing slopes and excavating earth. The analysis of nail-reinforced slopes, in order to determine the economical length ratio and nail angle, complicated analytical need to be applied by means of computer programs. Therefor this suggested Soil stability Chart for nailed slopes which may be very useful for pre-design, rapidly design, and final check. Three slope types, three nail length and three nail angles are selected for the stability analysis by using limit equilibrium method of Bishop and French Method. From the above results, this study propose the slope reinforced design charts for dry season and rainy season. This proposed reinforced design charts can check dry season as well as rainy season, also these charts can provide reinforcing requirement, soil nail's economical length ratio and nail angle as well.

• 한국지반공학회논문집
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• 제20권1호
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• pp.37-47
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• 2004

본 연구에서는 암반에 근입된 현장타설말뚝의 지지력을 높이기 위해 말뚝 주면에 soil nail을 정착한 타설말뚝의 축하중 해석을 수행하여 그 거동을 파악하였으며, soil nail의 유ㆍ무에 따른 보강효과를 분석하였다. 이를 위해 Beam-Column모델을 이용하여 현장타설말뚝과 지반을 모델링하고 하중전이곡선을 사용하여 말뚝지반의 상호작용을 고려하였다. 무보강 말뚝의 경우, 서해대교 현장재하시험결과 및 범용 프로그램인 Shaft 4.0의 해석결과와 비교ㆍ분석을 수행하였다. 보강형 말뚝의 경우에는 말뚝이 타설되는 지반을 [사질토+풍화암], [사질토+연암], [사질토+경암]으로 나누어 지반조건에 따른 soil nail의 보강효과를 파악하였다. 본 해석결과와 현장 실측치, SHAFT 4.0의 해석결과를 분석한 결과 제안된 주면하중전이함수 중 사질토에서는 Vijayvergiya의 함수, 암반에서는 O'Neill-Hassan의 함수가 암반에 근입된 현장타설말뚝의 거동을 비교적 적절히 예측함을 알 수 있었다. 이를 토대로 예측한 보강형 현장타설말뚝의 보강효과는 soil nail까지 하중전이가 나타나는 풍화암층에서 가장 크고, 암질이 양호한 연암과 경암층에서는 그 효과가 그다지 크지 않음을 알 수 있었다.

• Computers and Concrete
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• 제22권2호
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• pp.221-225
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• 2018

In this paper, vibration analysis of concrete foundations resting on soil medium is studied. The soil medium is simulated by Winkler model considering spring element. The concrete foundation is modeled by thick plate elements based on classical plate theory (CPT). Utilizing energy method consists of potential energy, kinetic energy and external works in conjunction with Hamilton's principle, the motion equations are derived. Assuming the simply supported boundary condition for the concrete foundation, the Navier method is used for calculating the frequency of the structure. The effect of different parameters such as soil medium, mode numbers, length to width ratio and length to thickness ratio of the concrete foundation are shown on the frequency of the structure. At the first, the results are validated with other published works in order to show the accuracy of the obtained results. The results show that considering the soil medium, the frequency of the structure increases significantly.

• Geomechanics and Engineering
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• 제38권3호
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• pp.261-273
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• 2024

This study presents a groundbreaking analytical approach to find an exact solution for the bearing capacity of strip footings on reinforced slopes, utilizing the two-phase approach and slip line method. The two-phase approach is considered as a generalized homogenization technique. The slip line method is leveraged to derive the stress field as a lower bound solution and the velocity field as an upper bound solution, thereby facilitating the attainment of an exact solution. The key finding points out the variation of the bearing capacity factor N_γ with influencing factors including the backfill soil friction angle, the footing setback distance from the slope crest edge, slope angle, strength, and volumetric fraction of inclusion layers. The results are evaluated by comparing them with those of relevant studies in the literature considering analytical and experimental studies. Through the application of the two-phase approach, it becomes feasible to determine the tensile loads mobilized along the inclusion layers associated with the failure zone. It is attempted to demonstrate the results by utilizing non-dimensional graphs to clearly illustrate variable impacts on reinforced soil stability. This research contributes significantly to advancing geotechnical engineering practices, specifically in the realm of static design considerations for reinforced soil structures.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 창립총회 및 춘계학술발표회
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• pp.3-8
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• 2000

A simple and rapid simultaneous analysis method of BTEX and TPH in soil was developed. 5g of soil sample were mixed with sodium sulfate and then extracted with 10 mL of mixture of acetone and dichloromethane (1:1). Extraction was performed for 10 min in sonicator and analysis was with GC-FID. The detection limits of BTEX and TPH was 0.8 and 10 mg/kg, respectively. The analytical recoveries were >90% for all BTEX and TPH. Low boiling point fuels and high boiling point fuels are consistently reproduced within RSD 7%. The analysis results show very simple and rapid quantitation of BTEX and TPH in soil sample with low RSD.

• 농약과학회지
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• 제18권4호
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• pp.258-268
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• 2014

OECD Test guideline 307에 따라 확립한 토양대사 시험법으로, 호기성 토양 조건에서 [$^{14}C$]butachlor의 토양대사 시험을 실시하였다. 시험토양은 국내 밭토양의 대표적인 토성인 양토였으며, 비멸균 및 멸균토양에 [$^{14}C$]butachlor ($6.83mgKg^{-1}$)을 처리하고 flow-through system에서 60일간 배양하였다. 시험기간 동안 mass balance는 비멸균 토양과 멸균토양에서 각 처리방사능 대비 91.1~95.5%, 93.0~97.7% 수준이었다. 비멸균 토양의 경우 처리 후 60일 경과 시 처리방사능의 8.4%로 감소하였으며, $DT_{50}$과 $DT_{90}$은 10.4일과 34.6일이었다. 토양 추출액 중 주요대사산물 2-chloro-2',6'-diethylacetanilide이 검출되었다. $^{14}CO_2$ 및 비추출성 토양잔류물은 3.5%와 43.5% 수준이었다. 시험기간 중 멸균 토양 내 [$^{14}C$]butachlor의 분해는 거의 일어나지 않았다. 따라서 butahclor는 호기성 토양에서 미생물에 의해 빠르게 분해되어 주요 대사산물 2-chloro-2',6'-diethylacetanilide와 $CO_2$를 생성하거나 토양에 강하게 흡착되어 비추출성 잔류물로 존재하는 것으로 판단된다. 이를 통해 OECD guideline TG 307에 확립한 호기성토양대사 시험법은 농약의 위해성 평가를 위한 토양 동태 예측 있어 국내 활용에 적합할 것으로 판단된다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 춘계학술대회 논문집
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• pp.108-119
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• 2001

The Spectral Analysis of surface Waves(SASW) Method has a great has a great potential for rapid determination of shear wave velocity profile of ground. However, it has an inherent limitation in the interpretation of test results due to the assumption that the ground is layered horizontally. The reason of the assumption is that difficulties exist in obtaining analytical solutions of wave equation when a soil system is composed of inclined soil layer. In this study, a finite-element method has been employed to assess the effects of dip angle and stiffness contrast of inclined soil layers and the testing direction on the dispersion curve. The propagation of wave front in the inclined soil layer was also investigated. The results indicated that the influence of dip angle on the dispersion curve is getting obvious as the dip angle increases and the propagation of wave front in the inclined layer also entirely different compared with the case of the horizontal layer.