• Ecology and Resilient Infrastructure
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• 제2권3호
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• pp.237-246
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• 2015

대한민국은 도시화 과정과 인접 국가에서부터 대기를 통한 유입 등으로 납과 같은 중금속의 토양 오염 문제가 관심을 받고 있다. 이에 가로수 수종으로 많이 쓰이고 있는 자생종 4종을 대상으로 토양 내 납 오염에 대한 엽록소 함량, 항산화 효소, 광합성량, 생물량과 같은 생리-생태적인 반응과 흡수능력을 연구하여 납 오염에 대응하는 가로수로 적합한 수종을 제시하고자 하였다. 연구 대상종인 은행나무, 왕벚나무, 느티나무, 이팝나무는 200 mg Pb/kg 이상의 처리구에서 엽록소 함량, 항산화 효소에서 납 독성에 대한 반응을 보였다. 반면에 생물량이나 광합성량의 경우 고농도 (5,000 mg/kg)를 제외하고는 큰 차이를 나타내지 않았다. 특히 은행나무는 항산화 효소, 광합성 및 생물량에서 고농도에서도 납의 부정적인 영향이 나타내지 않았다. 실제 환경에서 나타날 수 있는 저농도 처리구에서 은행나무와 벚나무의 경우 연구 대상종 중 높은 납 흡수율을 보였다. 이처럼 은행나무와 같이 납에 대한 저항력과 흡수능력을 가진 수종을 선발하여 가로수로 식재하여 도로 주변 납 오염에 대응하는 방안이 필요할 것이다.

• International Journal of Precision Engineering and Manufacturing
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• 제8권1호
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• pp.46-51
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• 2007

Environmental contamination creates shortages of potable water. In such situations, the leakage of water due to breakage or aging of rubber valve seats is a serious problem. Rubber is apt to break when it is placed between two materials that contact each other. One way to avoid water leakage due to rubber damage and breakdown is to replace the rubber with metal, which is currently taking place in water distribution systems. In tribology, a severe form of wear is characterized by local macroscopic material transfer or removal, or by problems with sliding protrusions when two solid surfaces experience relative sliding under load. One of the major problems when metal slides is the occurrence of galling. Experimentally, various conditions influence incipient galling, such as hardness, surface roughness, temperature, load, velocity, and the external environment. This study sought to verify the galling tendencies of metal according to its hardness, surface roughness, load, and sliding velocity, and determine the quantitative effect of each factor on the galling tendencies.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.581-586
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• 2000

Gas metal arc welding(GMAW) uses a continuously fed electrode as a filler metal. The arc is shielded from atmospheric contamination by an inert gas active or inert/active gas mixture delivered through the welding gun and cable assembly. The recent research topics on $CO_2$ are welding machines are focused mainly on the reduction method of generated spatter by using new type consumable electrode metal or inverter control method. The various current waveform control methods have been researched for welding performance improvement. Until now current waveform control methods reduce to spatter occurred by instantaneous short circuiting,. but these methods is drawback that no reduce spatter occurred by arc reignition. In this paper the previous arc reignition current control method for welding performance improvement of inverter arc welding machine is studied and compared the various current control methods with the previous arc reignition current control method.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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• pp.183-188
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• 1998

The efficiency of removing cadmium, copper, and lead from a contaminated soil of abandoned metal mine was studied in a laboratory investigation where citric acid were used to extract the metal from the soil. The contamination level of Pb, Cu in the soil A were 875.5, 667.5mg/kg respectively. The mobility and bioavailability of the metals in soil were also estimated by Sequential Chemical Extractions. Citric acid were examined for its potential extractive capabilities. Concentrations of the acid examined in this study ranged from 0.025 to 0.15M. The pH of the suspensions and S/S ratio in which the extractions were performed ranged from 2.4 to 8.1, and from 2.1:1 to 20:1. Results showed that the removal of contaminant using citric acid was pH and S/S raton dependent.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.210-214
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• 2002

In this study, the coupled effect of electrokinetic and ultrasonic remediation technology was investigated for removing of heavy metal and organic matter at the same time. The laboratory tests were conducted using specially designed and fabricated electrokinetic and ultrasonic devices. The electrokinetic technique was applied to remove mainly the heavy metal and the ultrasonic technique was applied to remove mainly organic substance in contaminated soil. Diesel fuel and Cd were used as a surrogate contaminant for this test. A series of laboratory experiments involving electrokinetic and electrokinetic+ultrasonic flushing test were carried out. An increase in permeability and contaminant removal rate was observed in electrokinetic+ultrasonic flushing test.

• Ocean and Polar Research
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• 제25권4호
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• pp.645-652
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• 2003

The coastal environment of King George Island is potentially subject to contamination by pollutants arising from station operations, such as emissions from fossil fuel burning, oil spills, waste disposal, etc. As a preparatory step to assess such impacts on the marine environment and living organisms of this island, two molluscan species (the bivalve Laternula elliptica and the gastropod Nacella concinna) were selected as biomonitors for metal pollution monitoring, and their baseline levels have been investigated for the past several years at King Sejong Station. In this review, variability of the baseline levels is discussed in relation to body size, tissue type, and sex. Natural elevations of some metals are also discussed with respect to the environmental characteristics of this region.

• 한국식품영양과학회지
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• 제29권5호
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• pp.758-761
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• 2000

This study was performed to investigate the contamination levels of harmful heavy metals that sampled from June. 1 to June. 31, 1999, at 3 areas in Jeonbuk west cost area. The heavy metal contents were determinated by ICPS (Inductively Coupled Plasma Spectrometer) method. The levels of total lead, cadmium, aluminum, zinc and copper were determined and the results were summarized as follows: The minimum and maximum values (ppm) of 3 areas of shellfishes (shortneck clam, hard clam, cockle clam, snail and top sell) were Pb: 1.29~4.35, Cd:0.12~0.37, Al: 9.45~54.06, Zn: 9.65~15.14, Cu: 0.62~1.64 ppm.

• 생명과학회지
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• 제20권9호
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• pp.1378-1384
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• 2010

안동호와 임하호에 서식하는 끄리(O. bidens), 잉어(C. carpio), 치리(H. eigenmanni), 백조어(C. brevicauda)의 부위에 따른 중금속 축적량을 비교하여 수환경 내 중금속이 어류에 미치는 영향을 알아보고자 하였다. 안동호와 임하호에 서식하는 어류의 중금속 함량은 안동호에 서식하는 어류에서 높은 함량을 보였으며, 중금속에 따라 함량의 차이도 컸다. 안동호와 임하호에 서식하는 어류에서 Cr, Cu, Zn 및 Pb은 뼈 조직에서 높은 함량을 보였고, Cd는 신장 조직에서 높은 함량을 보였다. 부위별 중금속함량은 Pb와 Zn을 제외한 전 중금속에서 높은 차이를 보였으며, 중금속별로는 Zn이 가장 많았고 Cd가 가장 낮았다. 또한 Cr은 안동호의 어류에서 임하호 보다 2배의 높은 함량의 차이를 보였다. 본 연구의 결과 안동호에 서식하는 어류가 임하호에 서식하는 어류 보다 중금속 함량이 높았으며, 이는 안동호의 수질과 저니에서 중금속 함량이 높은 것으로 보아 수환경의 수질과 저니에 포함된 유기물을 어류가 먹이로 섭취함으로써 어류에서도 높은 함량을 보인 것으로 생각된다.

• 한국지구과학회지
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• 제24권8호
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• pp.711-720
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• 2003

전주시 도로변 퇴적물의 중금속 오염을 평가하고 특성을 알기 위해 2002년 여름과 겨울 두 차례에 걸쳐 67곳에서 134개의 시료를 채취했다. 이들 시료를 Thompson and Wood (1982)와 Tessier et al. (1979)의 방법으로 화학처리한 후 Cd, Co, Cr, Cu, Ni, Pb, Zn, Mn등의 원소를 분석했다. 전주 도로변 퇴적물에 함유된 Zn, Cu, Pb, Cd의 함량은 서울의 도로변 토양, 먼지, 하수 슬러지에 함유된 것 보다 낮지만 세계 여러 나라에서 제시하는 토양 중 환경기준값을 초과했으며 자연 토양 중의 함량 보다 2-7배 초과한 값이다 산업지역, 상업지역, 주거지역으로 구분해 분석한 결과 전반적으로 산업지역에서의 중금속 함량이 약간 높고(특히 Cr, Ni, Pb, Zn)오염지수도 높다. 상업지역과 주거지역간의 중금속 오염 정도는 비슷하며 산업지역이 아니라도 특정 금속 가공업체나 자동차 정비 관련 업체가 위치해 있는 곳은 오염이 심하다. 연속추출 결과 중금속 원소의 존재 형태는 Pb, Zn, Mn등은 주로 탄산염 광물과 수반되거나 Fe-Mn산화물과 수반된 형태로 존재하고, Cu는 유기물과 함께 존재하는 비율이 높다. 그러나 전체적으로 규산염광물과 수반된 형태로 존재하는 비율이 50% 이상을 차지한다. 따라서 서울 지역에 비해 인위적 오염의 정도가 낮은 편이지만, Cd, Co, Ni, Pb, Zn, Mn등의 원소가 탄산염 형태로 존재하는 비율이 높기 때문에 오염원으로서의 가능성이 높다.

• 자원환경지질
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• 제31권6호
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• pp.499-508
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• 1998

The Imgok Creek is located in the Gangreung coal field, which has been known that sulfides are more abundant than other coal fields in Korea, and it has been severly contaminated by acid mine drainage (AMD) discharging from the abandoned coal mines, such as the Youngdong, the Dongduk and the Waryong coal mines. The purposes of this study are to synthetically assess the contamination of natural water, stream sediment and cultivated soils, and to provide the basic data for AMD treatment. Geochemical samples were collected in December, 1996 (dry season) and April, 1997 (after three day's rainfall). TDS of the Youngdong mine water was remarkably higher than those of other mine waters. In the Imgok Creek, concentrations of most elements, except Fe decreased with distance by dilution caused by the inflow of uncontaminated tributaries. From the results of NAMDI and $I_{geo}$ calculation, the Youngdong coal mine was the main contamination source of the study area. Groundwater pollution was not yet confirmed in this study and the paddy and farm land soils were also not yet contaminated by mining activity based on the pollution index ranging from 0.27 to 0.47.