• 한국지반환경공학회 논문집
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• 제7권4호
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• pp.35-41
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• 2006

임하호의 고탁도 유발물질에 대한 근본원인물질을 규명하기 위하여 영양과 청송 6개 지역 시료에 포함되어 있는 토양 성분의 용출성과 성분을 분석하였다. 채취된 시료의 주성분을 분석해 보면 vermiculite(V), illite(I), kaolinite(Ka), quartz(Q), feldspar(F)가 전체의 80% 이상을 차지하고 있는 것으로 확인되었다. 산성과 청기지역의 토양에서는 Na와 Ca이 대량 용출되었으며, 특히 Ca는 수계와 접촉 시 이온의 용출이 급격히 이루어지며 이때 용출된 이온이 pH를 상승시키는 알칼리성 성분으로 확인되었다. 영양일대에 위치한 점토질 토양 중에는 calcite 성분이 포함되어 있어 강우 시 수분에 의해 쉽게 용해되며 이로 인하여 토양 입자들을 수 ${\mu}m$ 크기로 분리시키는 작용을 수반하고 있어서 임하호의 고탁도 발생과 pH 상승의 주요 원인으로 작용할 것으로 사료된다.

• 한국환경과학회지
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• 제14권1호
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• pp.71-80
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• 2005

Soil is one of the most fundamental elements as well as with water and air in studies associated with the environment, in addition, it is one of the important environmental mediums that constructs a basis of the bio­logical system and performs various roles of matter circulation. This study was carried out in Seoul, in May 2000 to evaluate variation in the concentration levels and distribution characteristics for PAH compounds in soil. Soil samples were collected from 33 sites covering traffic, factory, incineration and mountain groups and the PAHs were analyzed. The results show a wide dis­tribution range of PAHs concentrations between 14.66 ng/g and 1,219.35 ng/g. The highest concentration levels exist at Sungsu-2 of the factory group (FS-2). Daemo-3 of the Mountain group (MD-3) presents the lowest levels as compared with the other sites. PAH compounds including mutagenic and carcinogenic materials show high concentrations in the traffic and factory groups and a high ratio in the mountain group. Besides, these compounds absorbed with micro particles might be spread out over a wide region associated with particles' movement and diffusion. After principal component analysis of the soil samples, the results indicated that the sources of PAHs in the soil were divided into two groups, pesticides and vehicles.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1182-1189
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• 2010

The mechanical behavior of a granular material is governed by the applying effective stresses and its skeletal structure which is considered to be the packing of particles giving overall density and degree of anisotropic. Factors that affect soil packing are the particle size, size distribution and shape, and the arrangement of grain contact. Soil particle size and shape are the most important factor, but difficult to quantify. In this study, 2D Fourier analysis is applied to quantify the shape of granular particles. Jumunjin sand was used in the experiment and particle images are captured using an optical microscope. The results showed that three lower order Fourier descriptor are closely related with roundness, sphericity of the granular particle. Also statistical approach is used to determine roundness, form factor, elongation ratio, roughness of Jumunjin sand.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 추계학술발표회
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• pp.115-119
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• 2001

Contaminant retardation factor is derived from the colloidal and contaminant transport equations for a four-phase porous medium: an aqueous phase, two mobile colloidal phases, and a solid matrix. It is assumed that the contaminant sorption to solid matrix and colloidal particles and the colloidal deposition on solid matrix follow the linear isotherms. The behavior of the contaminant retardation factor in response to the change of model parameters is examined employing the experimental data of Magee et al. (1991) and Jenkins and Lion (1993). In the four-phase system, the contaminant retardation factor is determined by both the contaminant association with solid matrix and colloidal particles and the colloidal deposition on solid matrix. The contaminant mobility is enhanced when the affinity of contaminants to mobile colloids increases. In addition, as the affinity of colloids to solid matrix decreases, the contaminant mobility increases.

• Environmental Engineering Research
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• 제22권2호
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• pp.224-229
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• 2017

Zinc oxide nanoparticles (ZnO NPs) have been used as additives in a variety of consumer products. While these particles may enter the environment, only a limited number of studies have investigated the effects of ZnO NPs on soil exoenzymes. Here, we investigate the long-term effects of ZnO NPs at concentrations of 50 and 500 mg/kg on the activities of six soil exoenzymes in planted soils: Dehydrogenase, fluorescein diacetate (FDA) hydrolase, urease, acid phosphatase, arylsulfatase, and ${\beta}-glucosidase$. Significant effects were observed at one or more time points for all enzymes except for FDA hydrolase. These effects included both decreases and increases in enzyme activity. Our results suggest that ZnO NP treatments of 50 and 500 mg/kg can adversely affect soil enzymes, particularly acid phosphatase and urease, and thus, these data may have implications for phosphorous and nitrogen cycles in the soil.

• Geomechanics and Engineering
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• 제19권3호
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• pp.229-240
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• 2019

The physical models are useful to understand the soil behaviour. Hence, these tools allow validating analytical theories and numerical data. This paper addresses the design, construction and implementation of a physical model able to simulate the soil liquefaction under different cyclic actions. The model was instrumented with a piezoelectric actuator and a set of transducers to measure the porewater pressures, displacements and accelerations of the system. The soil liquefaction was assessed in three different grain size particles of a natural sand by applying a sinusoidal signal, which incorporated three amplitudes and the fundamental frequencies of three different earthquakes occurred in Colombia. In addition, such frequencies were scaled in a micro shaking table device for 1, 50 and 80 g. Tests allowed identifying the liquefaction susceptibility at various frequency and displacement amplitude combinations. Experimental evidence validated that the liquefaction susceptibility is higher in the fine-grained sands than coarse-grained sands, and showed that the acceleration of the actuator controls the phenomena trigging in the model instead of the displacement amplitude.

• Geomechanics and Engineering
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• 제36권3호
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• pp.295-301
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• 2024

Understanding the post-liquefaction shear behavior is crucial for predicting and assessing the damage, such as lateral flow, caused by liquefaction. Most studies have focused on the behavior until liquefaction occurs. In this study, we performed undrained multi-stage tests on clean sand, sand-silt mixtures, and silty soils to investigate post-liquefaction shear strain based on soil compressibility. The results confirmed that it is necessary to consider the soil compressibility and the shape of soil particles to understand the post-liquefaction shear strain characteristics. Based on this, an index reflecting soil compressibility and particle shape was derived, and the results showed a high correlation with post-liquefaction small resistance characteristic regardless of soil type and fine particle content.

• Asian Journal of Atmospheric Environment
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• 제4권2호
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• pp.97-105
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• 2010

A quantitative single particle analytical technique, denoted low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA), was applied to characterize particulate matters collected at two underground subway stations, Jegidong and Yangje stations, in Seoul, Korea. To clearly identify the source of the indoor aerosols in the subway stations, four sets of samples were collected at four different locations within the subway stations: in the tunnel; at the platform; near the ticket office; nearby outdoors. Aerosol samples collected on stages 2 and 3 ($D_p$: $10-2.5\;{\mu}m$ and $2.5-1.0\;{\mu}m$, respectively) in a 3-stage Dekati $PM_{10}$ impactor were investigated. Samples were collected during summertime in 2009. The major chemical species observed in the subway particle samples were Fe-containing, carbonaceous, and soil-derived particles, and secondary aerosols such as nitrates and sulfates. Among them, Fe-containing particles were the most popular. The tunnel samples contained 85-88% of Fe-containing particles, with the abundance of Fe-containing particles decreasing as the distances of sampling locations from the tunnel increased. The Fe-containing subway particles were generated mainly from mechanical wear and friction processes at rail-wheel-brake interfaces. Carbonaceous, soil-derived, and secondary nitrate and/or sulfate particles observed in the underground subway particles likely flowed in from the outdoor environment by human activities and the air-exchange between the subway system and the outdoors. In addition, since the platform screen doors (PSDs) limit air-mixing between the tunnel and the platform, samples collected at the platform at the Yangjae station (with PSDs) showed a marked decrease in the relative abundances of Fe-containing particles compared to the Jegidong station (without PSDs).

• 한국토양비료학회지
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• 제13권2호
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• pp.57-63
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• 1980

시판(市販)되고 있는 광재규산질비료를 사별(篩別)하여 10목이하(目以下) 20-35목(目) 및 100목이상(目以上)의 3개입자군(個粒子群)으로 분리(分離)하고 그들을 토양(土壤)에 처리했을 때 토양용액(土壤溶液)의 규산함량변화(珪酸含量變化), 토양(土壤)에서의 이동성(移動性) 등을 조사(調査)한바 다음과 같은 결과(結果)를 얻었다. 1. 규산질비료(珪酸質肥料) 20mg을 증류수50ml로 침출(浸出) 했을 때 용액(溶液)의 규산농도(珪酸濃度)는 10목이하(目以下), 20-35목(目), 100목이상(目以上) 입자(粒子)에 처하여 각각 0.3, 1.0, 3.2ppm 이었으며 1N-Na-acetate용액(溶液)으로 침출(浸出)했을 때의 농도(濃度)는 각각 24.5, 126.2, 225.5ppm 이었다. 2. 규산질비료(珪酸質肥料) 20mg을 첨가(添加)한 상양(上壤)20g을 증류수 50ml로 침출(浸出)했을 때 10목이하(目以下), 20-35목(目), 100목이상(目以上) 입자(粒子)의 규산질비료(珪酸質肥料)를 처리한 토양용액중(土壤溶液中)의 규산농도(珪酸濃度)는 규산(珪酸)을 첨가(添加)하지 않았을 때 보다 각각 0.25, 0.97, 3.28ppm 증가하였다. 3. 토양용액(土壤溶液)의 pH는 규산질비료(珪酸質肥料)의 첨가(添加) 여부와 관계(關係)없이 담수일수(湛水日數)와 함께 2~4주(週)까지는 상승(上昇)하고 그 후(後) 6~10주(週)까지 하강(下降)하였다. 이때 수용액중(水溶液中)의 규산농도(珪酸濃度)는 pH와 역상관(逆相關)을 냐타내었으나 담수(湛水) 6~10주이후(週以後)에는 pH와 관계(關係)없이 수용액중(水溶液中)의 규산농도(珪酸濃度)는 증가하였다. 4. 토양투하수(土壤透下水)의 분액별(分液別) 규산농도(珪酸濃度)는 규산질비료(珪酸質肥料)를 첨가(添加)하지 않았을 경우 투과수(透過水)의 양(量)이 0.88 pore volume에 달(達)했을 때 최고치(最高値)를 나타내었으며 20-35목(目), 100목이상(目以上)의 규산질비료(珪酸質肥料)를 첨가(添加)하였을 때에는 각 각 0.94, 1.03pore volume에서 최고농도(最高濃度)를 나타내었다. 5. 1.5pore volume의 증류수를 투하(透下)시킨 후(後) 토양(土壤) column의 부위별(部位別) 규산함량(珪酸含量)을 분석(分析)한 바 수용성(水溶性) 규산(珪酸) 함량(含量)은 6~9cm이하에서는 깊이에 관계없이 일정(一定)하나 그 위 부위(部位)에서는 위로 갈수록 낮은 함량(含量)을 나타내었다. 그러나 1N-Na-acetate 가용규산(可溶珪酸)은 이동(移動)되지 않고 규산(珪酸) 처리부위에 집적(集積)되어 있었다.

• 한국토양환경학회지
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• 제5권2호
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• pp.13-21
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• 2000

유수지는 생활하수 및 정수 처리된 하수를 바다에 방류하기 전에 하수방류가 조수의 영향으로 역류하는 것을 막기 위해 설치된 일종의 하수 저류시설이다. 본 연구에서는 현장에서 준설한 시료에 대하여 실내시험을 실시하여 유수지 하상 오니가 포함하고 있는 실토사의 적정량을 산출하였다. 또한, 준설오니를 임시 저장한 슬러지 저장 연못에서 시료를 채취하여 실내시험을 실시하여 준설용적을 산출하였다. 본 연구결과, 준설오니의 비중은 2.17∼2.29로 일반적인 점토보다 상당히 낮은 값으로, Gypsum과 유사한 값을 나타내었다. 또한, 함수율은 300∼700%의 범위를 나타내었다. 준설토로부터 물을 제거함에 따른 유실용적은 전체용적의 78.2∼87.5%의 범위로, 준설오니의 실토사 적정토량은 12.5∼21.9%의 범위를 나타내었다. 유수지 준설오니와 고화처리시료에 대한 중금속함량(크롬, 아연, 구리, 카드뮴, 수은, 비소, 납)시험결과 국내 관계법령 중 가장 엄격한 해양오염방지법 기준에 모두 만족하는 결과를 나타내었다.