• 한국지하수토양환경학회지:지하수토양환경
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• 제16권5호
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• pp.18-23
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• 2011

The electrokinetic transport characteristics of salts were investigated using nitrate and sulfate accumulated saline greenhouse soil. Within 8 days, 95% of nitrate was removed from the soil, while sulfate removal was 19% for 8 days. The low removal of sulfate came from adsorption reaction on the soil particles or organic matter and precipitation with calcium. Divalent cations such as calcium and magnesium were transported toward cathode via electromigration, and most monovalent cation such as potassium was removed. The pattern of residual electrical conductivity was similar with that of sulfate. Based on the results, electrokinetic technique is effective to restore nitrate-accumulated saline soil, but is not effective to restore sulfate-accumulated soil.

• 한국패류학회지
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• 제26권3호
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• pp.179-183
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• 2010

In other to understand the effect of yellow soil to mortality of Korean scallops, P. yessoensis, We investigated its mortality at indoor tanks. The environmental conditions such as water temperature, Salinity, Do and pH were continued constantly during the experimental periods. The 100% of survival rate showed in two experiments groups such as 0.1% and 0.4% of concentration of yellow soil and the other groups as 0.05% and 0.2% of concentration of yellow soil was appeared one dead scallop at each group for 8 days of the experiment periods. the gills of scallop in high concentration of yellow soil (0.2% and 0.4% groups) were covered by yellow soil particles so that this group's scallop should be got a high stress from yellow soil. I think this situation will be more continued for long time the scallop will become to dead. The results of bacteriological analysis did not isolated from haemolymph of scallops and no Perkinsus infectious disease in scallops and the scallops showed necrosis and degeneration on digestive grand and gills of scallop.

• 센서학회지
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• 제30권6호
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• pp.415-419
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• 2021

We developed a highly accurate, yet inexpensive, refractive index (RI)-based soil moisture sensor. To detect the RI, a light guide was set with a light-emitting diode and photodiode. When the air fills the space between the soil particles, most of the incident light is reflected at the interface between the waveguide and the air because of the large RI difference. As the moisture of the soil increases, the macroscopic soil RI increases. This allows incident light to pass through the interface. The intensity of the light reaching the photodiode was simulated according to the change in the soil RI. Using the simulation results, we designed and manufactured a curved glass waveguide. We evaluated the performance of the RI-based soil sensor by comparing it with a commercially available, high-cost and high-performance time-domain reflectometer (TDR). Our sensor was 96% accurate, surpassing the costly TDR sensor.

• 한국재난정보학회 논문집
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• 제20권1호
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• pp.169-176
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• 2024

연구목적: 본 논문에서는 직접전단시험에서 시험시편의 규모 때문에 부득이 굵은 입자가 제외되는 문제 때문에 발생되는 전단강도의 차이를 분석하고자 직접전단시험을 실시하는 실험연구를 수행하였다. 연구방법: 최대직경 50mm의 굵은 골재가 포함된 3개의 풍화토를 대상으로 대형직접전단시험을 실시하였다. 또한 굵은 골재가 제외된 최대직경 5mm 시료를 이용하여 소형직접전단시험을 실시하였다. 연구결과: 소형직접전단시험의 경우 큰입자가 포함된 대형직접전단시험의 결과에 비하여 내부마찰각은 약2.3% 작은 값을 도출하여 비교적 큰 차이가 없었다. 점착력에서는 대형직접전단시험에 비하여 소형 직접전단시험이 약 80.3% 작은 값을 도출하여 비교적 큰 차이를 나타내었다. 결론: 대형직접전단시험에서 굵은 입자가 내부마찰각보다는 점착력에 큰 영향을 준 것으로 분석되었다. 따라서, 굵은 입자를 포함한 화강풍화토는 수직응력에 영향을 받지 않는 점착력과 같은 전단강도를 갖고 있는 것으로 판단된다. 본 연구에서는 일반적으로 사용되고 있는 굵은 입자를 제외한 소형직접전단시험은 굵은 입자의 효과를 제외함으로서 안전측의 결과를 제공하는 것으로 분석되었다.

• 한국초지조사료학회지
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• 제19권4호
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• pp.373-378
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• 1999

본 시험은 사양토에서 조성된 혼파초지에서 석회석의 입자도 및 패각분이 토양특성, 목초의 건물수량 및 사료가치에 미치는 영향을 구명하기 위하여 축산기술연구소 초지사료과의 시험포장에서 무처리, $Ca(OH)_2$, 도로마이트 0.5, 2.0, 4.0mm 및 패각분을 각각 중화량으로 총 6처리로 하여 '94년부터 '96년까지 실시하였다. 목초의 평균 건물수량은 소석회 > 도로마이트 2.0mm > 0.5mm > 무처리 > 4.0mm > 패각분 순이었으며 유의적인 수량차이는 없었다. 목초의 평균 조단백질 수량은 도로마이트 2.0mm > 0.5mm > 무처리 > 소석회 > 패각분 > 4.0mm 순이었다. 석회요구량은 연차가 경과할수록 ha당 2,410kg에서 4,853kg으로 크게 증가하였으며, 토양경도는 1년차와 2년차까지는 적정범위였으나 시용 후 시간이 경과할수록 토양이 단단해지는 경향이었다. 토양삼상은 도로마이트 0.5mm가 다른 처리에 비하여 고상함량이 낮았다. 이상의 결과로서 사양토에서는 도로마이트 2.0mm를 석회 대용으로 3년마다 시용하여 주는 것이 건물수량과 사료가치 측면에서 유리하다고 생각되며, 패각분은 자주 시용하는 것이 효과가 있다고 생각된다.

• 한국물환경학회지
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• 제38권2호
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• pp.72-81
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• 2022

Numerous studies have investigated the occurrence and fate of microplastics in the environment; however, only limited effort has been devoted to exploring the characteristics of dissolved organic matter (DOM) leached from microplastics. In microplastic (MP)-contaminated environment, MPs are typically mixed with naturally-occurring particles, which interferes with their detection in the environment. Thus, it is necessary to distinguish between the DOM leached from MPs and those leached from natural particles and also to characterize their properties. This study investigated DOM leaching behavior from MPs (polystyrene: PS, polyvinylchloride: PVC) and natural particulates (forest soil: FS, litter leaves: LL) under light, which is considered one of the main weathering processes that affect MPs in the environment. The leached DOM concentrations and fluorescence characteristics were compared under dark versus light conditions. Regardless of the origins, UV light promoted DOM release from all the particulates. More DOM was released from natural particles than from MPs under both conditions. However, the effect of promoting DOM release by UV was more pronounced for MPs than for natural particles. It was observed from fluorescence spectra that the intensity of the humic-like region was substantially reduced when MP-derived DOM was exposed to UV light, whereas the change of intensity was very little for natural particles. Under light conditions, the ratio of protein-like to humic-like fluorescence of MP-derived DOM was higher than that of DOM from natural particles. This study implies that a substantial amount of DOM could be leached from MPs even in MP-polluted environment under UV irradiation. Protein/humic fluorescence ratio could be utilized as a fast probing indicator to separate the two sources of particles under light.

• 한국대기환경학회지
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• 제19권4호
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• pp.415-425
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• 2003

A single particle analysis, called low-Z electron probe X-ray microanalysis was applied to characterize the atmospheric aerosols collected during Asian Dust storm events in the year of 2000 and 2001. Most frequently encountered chemical species were the soil-originated species such as aluminosilicates, silicon dioxide, and calcium carbonate. Also various species such as carbon -rich, organics, sea salts, and some reacted calcium carbonate were identified. The observation of internally mixed particles oi calcium carbonate, calcium nitrate and/or calcium sulfate shows the occurrence of the heterogeneous reaction between Asian Dust particles and NO$_{x}$ and/or SO$_{x}$ species in the atmosphere.ere.

• 한국대기환경학회지
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• 제5권2호
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• pp.72-83
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• 1989

Twenty-five atmospheric particulates were collected using a high volume aerosol sampler from Septermber to December, 1988 on a site located on the West coast of Korea and analysed for twelve elements (Na, Mg, Al, Mn, Fe, Cu, Co, Ni, Zn, Ag, Cd, and Pb) by AAS. The particles being mainly crustal minerals, large quantity of spherical fly ashes were also observed. In order to identify the origin of trace metals in atmospheric particulates, enrichment factor, interelemental correlation and factor analysis were performed. Based upon these analysis, the twelve elements can be classified into three groups; the elements dominantly present in soil particles (Al, Mn, Fe, Co, and Ni), those in sea salt aerosols (Na and Mg), and those in air pollution-derived particles (Cu, Cd, Pb, Ag and Zn).

• 한국제4기학회지
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• 제21권2호
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• pp.77-79
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• 2007

The source regions of Asian Dusts (Yellow Sands) in the western part of China are investigated, and the soil samples are collected samples for approximately 15 days during the spring of 2005. Particle sizes of sediments are analyzed and compared with each other. These grain-size analyses from the source areas can be compared Particle sizes between loess deposits and desert sands in western part of China and desert areas show distinctive differences. Loess deposits are predominantly composed of fine sands and silts. The distinction between the final characteristics of Asian Dust particles arrived in Korea and characteristics during transportation can be recognized comparison with the Asian Dust particles collected where the dust particles settled down. The characteristics of Asian Dust particle sizes can provide the basic information regarding the transportation history from the source region.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권1호
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• pp.27-32
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• 2017

Cesium (Cs) generated by nuclear accidents is one of the most hazardous radionuclides because of its gamma radiation and long half-life. Especially, when Cs is exposed on the soil environments, Cs is mainly adsorbed on the topsoil and is strongly combined with tiny soil particle including clay minerals. The adsorption of Cs onto soil can vary depending on various physicochemical properties of soil. In this study, the adsorption characteristics between soil and Cs were investigated according to various physicochemical properties of soil including organic matter contents, cation exchange capacity (CEC), soil particle size, and the types of clay minerals. Soil organic matter inhibited the adsorption of Cs onto the soil because organic matter was blocking the soil surface. In addition, it was estimated that the CEC of the soil influenced the adsorption of Cs onto the soil. Moreover, more Cs was adsorbed as the soil particles size decreased. It was estimated that Cs was mostly adsorbed onto the topsoil, this is related to the clay mineral. Therefore, soil organic matter, CEC, soil particle size, and clay minerals are considered the key factors that can influence the adsorption characteristics between soil and Cs.