• Journal of Soil and Groundwater Environment
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• v.10 no.2
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• pp.44-51
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• 2005

Fractional composition and mobility of some heavy metals in sediments from Okdong stream are investigated. The fractional scheme for heavy metals in the sediment was established for five chemically defined heavy metal forms as adsorbed fraction, carbonate fraction, reducible fraction, organic fraction, and residual fraction. The most abundant fraction heavy metals in the sediments is reducible and secondly abundant is organic fraction. Adsorbed fraction is minor part of the total heavy metals. Mobilization of heavy metals in the sediments from Okdong stream occur $19.8{\sim}56.7%$ of total cadmium concentrate. The most abundant fraction of the sediment metal is organic fraction in Cu, Pb metals investigated. Labile fraction of sediment metals are $0.5{\sim}48.5%$ of total Zn, $2.6{\sim}48.1%$ of total Pb, and $0.2{\sim}36.9%$ of total Cu, respectively. Most of labile fraction consists of reducible fraction for Cd, Zn, adsorbed fraction for Pb, reducible fraction for Cu, adsorbed fraction for Ni. The Mobilization of Zn and Cu is most likely to occur when oxygen depletes and that of Pb and Ni occurs when physical impact, oxygen depletion and pH reduction.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.699-705
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• 2005

In order to identify the speciation of As and trace elements which are contained weathered waste rocks on the abandoned Jangpoong Cu mine area, five fraction sequential extraction was carried out. Concentrations of the extraction solutions which were acquaired each fraction were mesured by ICP-AES. Mineral characters of weathered waste rocks were determinated by XRD. The weathered waste rocks could divide into two types (Type I and type II). Type land type II weathered waste rocks are mainly composed of a quartz and a calcite, respectively. The most dominant speciation of As, Co and Fe is residual phase. Most of the speciation of Cd, Mn and Zn is residual phase for type I and Fe-Mn oxide phase for type II. In case of Cu, residual phase is predominant in type I and sulfide is predominet in type II. The most dominant speciation of Pb for type I and type II is associated with the residual phase and Fe-Mn oxide phase, respectively. At pH 4-7 range, the order of relative mobility considers Zn>Cu>Cd>Pb>Co>AS in type I, and Cd>Cu>Zn>Pb>As>Co in type II.

• Resources Recycling
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• v.6 no.1
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• pp.35-39
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• 1997

This study was carried out to find the existing forms of chlorlnc in EM dust and to understand the valaliliratian behavior and the removal of chlorine from EAF dust with lemperalure and heating almosphere The chemical compositions of dust A are 27.3%Fe. 21.8%3Zn, 3 15%Pb, 3 51%C1 and that of dust B BE 33.92%Fe, 15.94%Zn, 2.73% Pb, 3.98%Cl. The XRD analysis and water leaching test shows that chlorlne in EM dust exist mainly as NaCI, KCI, Pb (0H)Cl. Above 99% of chlorine was volatilized when dust was hentcd in alr atmosphere at 1100$^{\circ}$C h r 1 hour and that was 96% when heated in reduction atmosnherc at 1100$^{\circ}$C for 1 hour.

• Journal of Labour Economics
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• v.11
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• pp.93-113
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• 1988

• Journal of Soil and Groundwater Environment
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• v.11 no.5
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• pp.20-34
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• 2006

This study was undertaken to assess the anthropogenic impact on trace metal concentrations (Zn, Cu, Pb, Cr, Ni, and Cd) of roadside sediments (N = 70) from No.7 national road within the watershed of Hoidong Reservoir in Pusan City and to estimate the potential mobility of selected metals using sequential extraction. We generally found high concentrations of metals, especially Zn, Cu and Pb, affected by anthropogenic inputs. Compared to the trace metal concentrations of uncontaminated stream sediments, arithmetic mean concentrations of roadside sediments were about 7 times higher for Cu, 4 times higher for Zn, 3 times higher for Pb and Cr and, 2 times higher for Ni and As. Speciation data on the basis of sequential extraction indicate that most of the trace metals considered do not occur in significant quantities in the exchangeable fraction, except for Cd and Ni whose exchangeable fractions are appreciable (average 29.3 and 25.8%, respectively). Other metals such as Zn (51.4%) and Pb (45.2%) are preferentially bound to the reducible fraction, and therefore they can be potentially released by a pH decrease and/or redox change. Copper is mainly found in the organic fraction, while Cd is highest in the exchangeable fraction, and Cr and Ni in the residual fraction. Considering the proportion of metals bound to the exchangeable and carbonate fractions, the comparative mobility of metals probably decreases in the order of Cd>Ni>Pb>Zn>Cr>Cu. Although the total concentration data showed that Zn was typically present in potentially harmful concentration levels, the data on metal partitioning indicated that Cd, Ni and Pb pose the highest potential hazard for runoff water. As potential changes of redox state and pH may remobilize the metals bound to carbonates, amorphous oxides, and/or organic matter, and may release and flush them through drain networks into the watershed of Hoidong Reservoir, careful monitoring of environmental conditions appears to be very important.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.9
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• pp.840-850
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• 2010

The present study was attempted to find the effects of structural properties of phosphorus on the water quality of Gyehwa reservoir in Saemangeum. Relationship of phosphorus fractions between water and sediment properties was closely examined, and a few types of phosphorus were found from the sample sediment as : Saloid-P, Al-P, Fe-P, Ca-P, Red-P and Occd-P. Saloid-P (1.4%), Al-P (0.5%), Fe-P (39.8%), Ca-P (56.6%), Red-P (0.4%), Occd-P (1.3%) were extracted in a mass basis from the sediment of Gyehwa reservoir. Approximately more than 97% of phosphorus were calcium related phosphorus (Ca-P, 56%) and iron bound phosphorus (Fe-P, 39.8%). The Fe-P closely relates with water quality of T-N (r=0.761, p<0.05), $NO_3$-N (r=0.754, p<0.05), $NH_4$-N (r=0.728, p<0.05), T-P (r=0.774, p<0.05) and $PO_4$-P (r=0.767, p<0.05) while the Ca-P did not show any consistent dependency on the water quality. On the other hand, the correlation of Ca-P with $P_2O_5$ was high with r=0.783 (p<0.05) in the sediment. The Fe-P was affected significantly on the Ignition Loss (r=0.569, p<0.05), T-N (r=0.715, p<0.05) and T-P (r=0.983, p<0.01). In the research of correlation between phosphorus fraction and heavy metals in the sediment, Ca-P did not show any specific relationships with heavy metals. The Fe-P showed a significant correlation with As (r=0.817, p<0.01), Cu (r=0.793, p<0.05), Cd (r=0.786, p<0.05), Zn (r=0.738, p<0.05), so that it can be stated that the presence of Fe-P may implicate the volume of various metallic elements.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.864-865
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• 2007

외전형 유도전동기는 내전형에 비해 회전자가 외부에 존재하는 특징을 가지고 있어서 제품의 소형화 및 경량화를 시킬 수 있다는 장점이 있다. 하지만 외전형은 회전자의 직경이 내전형에 비하여 크기 때문에 조립 공정상에 존재하게 되는 회전자와 고정자간의 이심률에 따른 제품 전체의 불균형력이 상대적으로 크며, 이로 인해 모터의 정속적인 운전 방해 및 불규칙한 출력토크로 인한 제품 작동상의 오류발생이 더 크게 나타난다. 본 논문에서는 외전형 유도전동기에서 존재하는 이심률의 크기에 따른 불균형력이 최소화 될 수 있는 슬롯형태를 찾기 위해 회전자 슬롯의 형태를 전폐형, 반폐형, 개구형태의 3가지형태로 변경시킨 후, 이를 전자장 해석을 통해 불균형력을 비교하였다. 또한 이심률이 증가함에 따라 나타나는 불균형력의 증대를 슬롯 형태에 따라 비교 분석하여, 불균형력에 최적화된 외전형 모터의 슬롯형태를 알아보았다.

• Korean Journal of Environmental Agriculture
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• v.25 no.2
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• pp.129-137
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• 2006

A study was conducted to investigate the behavior of pollutant forms at each area in the sewage treatment plant by natural purification method. The sewage treatment plant by natural purification method that consisted of aerobic and anaerobic area was constructed. The efficiency of sewage treatment depending on the operation time, the loading amount of pollutant season variation were investigated. The removal amount of BOD, COD, TOC and SS in the aerobic area was significantly increased as the treatment proceeded. Decreased BOD, COD, TOC, SS, T-N and T-P depending on the loading amount of pollutants in the aerobic and ananerobic area were mostly insoluble BOD (IBOD), insoluble COD (ICOD), soluble TOC (STOC), volatile SS (VSS), dissolved T-N (DTN) and dissolved T-N (DTP) types, respectively. The removal efficiency of BOD, COD, TOC, SS, T-N and T-P in hot season (summer and autumn) were more than that in cold season (spring and winter). The removal efficiencies of BOD, COD, TOC, SS, T-N and T-P of the effluent were about 92, 89, 73, 95, 46 and 84% in all seasons, respectively.

• Journal of Soil and Groundwater Environment
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• v.8 no.3
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• pp.45-55
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• 2003

This study investigates the fractional composition and the leaching characteristics of heavy metals in polluted soils due to mining activities. The fractionated composition of heavy metals is classified into five fractions; adsorbed, carbonate, reducible, organic and residual fraction. The status of humic substances in mine wastes of most sites are polyhumic except tailing from Sangdong mine. According to the sequential extraction procedures (SEPs), leaching probabilities of Cd in coal wastes and tailing are relatively low due to high percentage of residual fraction. 46.4% of Ni in tailings from Sangdong mine is probably leached under oxidized environment, and 39.4% of Cu in these tailings is readily extracted under strongly oxidized environment by organic fraction. According to leaching condition of pH 3.0 and pH 5.6, the amount of heavy metals leached out of coal wastes and tailing increases to 1/2 hours. At pH 3.0 and pH 5.6, concentration of Ni in tailing increases up three times of the initial value. Heavy metals released from coal wastes and tailing were not influenced significantly by leaching time.

• Economic and Environmental Geology
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• v.37 no.6 s.169
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• pp.657-667
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• 2004

Arsenic was detected in the 29 water samples out of the 46 groundwaters located in the Ulsan metropolitan area and it's concentration ranges from $<0.1\;to\;72{\mu}g/L$. Among them the arsenic concentrations of three samples are over domestic drinking-water requirements $(50{\mu}g/L)$, and those of 10 samples are more than WHO MCLs, $10{\mu}g/L.$. High arsenic groundwater were recognized in the two region; one was near the tectonic line, especially Ulsan iron mine at Dalcheunri and the other was around Hyomundong distributed Jeongia conglomerate. It is estimated that the former is originated from pyrite oxydation type, oxygenated redox, whilst the latter is resulted from oxidation of reducted FeOOH. The species of arsenic in groundwater is in pentavalent arsenic, $H_2AsO_4^-,\;HAsO4_^{-2}$ near tectonic line, and trivalent arsenic, $H_3AsO_3$ around Hyomundong.