http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Evaluation of layered and mixed passive treatment systems for acid mine drainage
Jeen, Sung-Wook,Mattson, Bruce Informa UK (TaylorFrancis) 2016 Environmental Technology Vol.37 No.22
<P>Laboratory column tests for passive treatment systems for mine drainage from a waste rock storage area were conducted to evaluate suitable reactive mixture, system configuration, effects of influent water chemistry, and required residence time. Five columns containing straw, chicken manure, mushroom compost, and limestone (LS), in either layered or mixed configurations, were set up to simulate the treatment system. The results showed that all of the five columns removed metals of concern (i.e. Al, Cd, Co, Cu, Fe, Ni, and Zn) with a residence time of 15h and greater. Reaction mechanisms responsible for the removal of metals may include sulfate reduction and subsequent sulfide precipitation, precipitation of secondary carbonates and hydroxides, co-precipitation, and sorption on organic substrates and secondary precipitates. The results suggest that the mixed systems containing organic materials and LS perform better than the layered systems, sequentially treated by organic and LS layers, due to the enhanced pH adjustment, which is beneficial to bacterial activity and precipitation of secondary minerals. The column tests provide a basis for the design of a field-scale passive treatment system, such as a reducing and alkalinity producing system or a permeable reactive barrier.</P>
Design of Passive Treatment Systems for Mine Drainage Waters
Jeen, Sung-Wook Korean Society of Soil and Groundwater Environment 2017 지하수토양환경 Vol.22 No.2
Passive treatment systems are commonly used for remediation of mine drainage waters because they do not require continuous chemical inputs and operation. In this study, the selection and design criteria for such systems were evaluated, particularly the two most commonly used ones, i.e., permeable reactive barriers (PRBs) and vertical flow biological reactors (VFBRs). PRBs and VFBRs are operated on the same principles in terms of biochemical reaction mechanisms, whereas differences relate to configuration, engineering, and water management. In this study, each of these systems were described with respect to key design variables, such as metal removal mechanisms and removal rates, effectiveness and longevity, general design and construction, flow capacity, and cost. The information provided from this study could be used as a design guideline when a passive treatment option is considered for potential remediation of a mine site.
Bench-Scale Flushing Experiments for Remediation of Hg-Contaminated Groundwater
Hindawi Limited 2016 Journal of chemistry Vol.2016 No.-
<P>Bench-scale laboratory column experiments were conducted to determine the desorption characteristics of Hg in the aquifer material from an area of known elevated Hg concentrations in groundwater under flushing conditions. The experimental results showed that columns packed with perched aquifer material (PA) showed flushing of Hg, with the general decline of effluent Hg concentrations over time (from 0.05-0.1 mg/L in the beginning to 0.0001-0.003 mg/L at the end of the experiment). Columns with lower aquifer material (LA) showed nondetectable level of effluent Hg throughout the experiment. Possibility of redissolution/desorption of Hg after static condition (for the duration of 18 days) was tested, showing only slight rebound of Hg concentrations after equilibration. The results suggest that removal of up to 20% of Hg inventory in the sediment could be achievable for the duration of the experiments (about 10 pore volumes). The results also indicate that the treated water from the water treatment plant was more effective compared to deionized water, probably due to complexing agents contained in the treated water.</P>
Injectable Apatite for the Sequestration of Sr-90 in Groundwater
Jeen, Sung-Wook,Hyun, Yunjung Korean Society of Soil and Groundwater Environment 2015 지하수토양환경 Vol.20 No.2
Laboratory column experiments were conducted to evaluate the feasibility of injectable apatite method for the sequestration of Sr-90 in groundwater. The columns were tested to evaluate the rate of citrate biodegradation, the amounts of apatite formed, and the treatability of strontium by the sediment and apatite. The results showed the decreases in citrate, calcium, and phosphate concentrations and the increases in alkalinity and citrate degradation products (acetate and formate) in the columns, suggesting that the citrate degradation and formation of calcium phosphate are occurring. Although the calcium and phosphate were not completely consumed within the columns, some amounts of apatite were formed and it showed an ability to treat strontium in groundwater. This study provides a fundamental understanding of reaction mechanisms for the injectable apatite sequestration method for Sr-90 removal.
Lee, Sung-Joon,Cho, Il-Hwan,Kim, Hyun-Wook,Hong, Sang-Jeen,Lee, Hun-Yong The Korean Institute of Electrical and Electronic 2009 Transactions on Electrical and Electronic Material Vol.10 No.5
Employing statistical design of experiments, we have performed studies on the characterization of electrodes using $TiO_2$ and process variables in the fabrication process of nanocrystalline dye sensitized solar cell. Systematic experiment to identify the effects of process variables on cell's efficiency has based on broad-band absorption of light by tailor made organometallic dye molecules dispersed on a high surface of $TiO_2$. Employing statistical design of experiment on $TiO_2$ photoelectrode forming process, structural characterization of electrodes and process variable have been investigated. Through the statistical analysis we have found that the particle size of $TiO_2$ and the amount of PEG/PEO are significantly affecting on the cell efficiency. In addition, a significant amount of interaction exists between the particle size and the amount of PEG/PEO.
Carditis 와 역류성 식도염 및 Helicobacter pylori 감염과의 관계
이상우 ( Sang Woo Lee ),박동규 ( Dong Kyu Park ),김창덕 ( Chang Duck Kim ),진윤태 ( Yoon Tae Jeen ),최재현 ( Jai Hyun Choi ),엄순호 ( Soon Ho Um ),류호상 ( Ho Sang Ryu ),전훈재 ( Hoon Jai Chun ),송치욱 ( Chi Wook song ),현진해 ( J 대한소화기학회 2001 대한소화기학회지 Vol.38 No.5
Background/Aims: The aim of this study was to investigate the relationship among squamocolumnar junctional inflammation (carditis), reflux esophagitis, and Helicobacter pylori (H. pylori) infection. Methods: Gastrofiberscopy was performed for 221 patients with various gastrointestinal symptoms. Endoscopic biopsies were performed at the distal esophagus of 3 cm above squamocolumnar junction (Z-line), Z-line, antrum, and body. Biopsy specimens were assessed for density of neutrophils and mononuclear cells (each scored 0-3), and for the presence of H. pylori. A carditis score above 2 was considered positive. Results: Among the 221 patients, 107 cases were defined as reflux esophagitis (RE) group and remaining 114 cases were defined as control group. The prevalence of carditis was significantly different between the two groups (RE, 35.5%; controls, 54.4%, p=0.005). The prevalence of H. pylori infection was also different significantly between the two groups (RE, 40.2%; controls, 57.9%, p=0.009). The relationship between H. pylori infection and carditis (p=0.001) or intestinal metaplasia (p=0.033) was statistically significant. Conclusions: Carditis and H. pylori infection can not be a marker of reflux esophagitis. H. pylori infection is associated with carditis and intestinal metaplasia at squamocolumnar junction. (Korean J Gastroenterol 2001;38:319-324)
Hyejung Jung,Sung-Wook Jeen,Hyoungseok Lee,Jeonghoon Lee 대한지질학회 2021 대한지질학회 학술대회 Vol.2021 No.10
Polar regions are under dynamic hydrological conditions due to the presence of active layers, which are freezing and thawing repeatedly. This study aims to investigate the hydrological process in a stream of a snow-dominated headwater catchment in King George Island in Antarctica using isotopic and chemical signatures of stream water. We identified that the chemical composition of stream water was correlated to the degree of interaction with soil and rock materials, and the isotopic composition was correlated to the rate of snowmelt rate. Our results showed a negative correlation between electrical conductivity (EC) and streamflow (r=0.65, p<0.0001). Additionally, we also observed a positive correlation between the stable isotopic composition of stream water and streamflow (r=0.64, p<0.0001). Based on these results, it was suggested that the active layer thickness played an important role in interpreting hydrological pathways at the catchment. During the cold summer period, the contribution of supra-permafrost groundwater was dominated because streamflow decreased, resulting from a refreezing of the snowpack, a cessation of snowmelt inputs, and a recession in the saturated soil layer. However, snowmelt runoff was also produced by limited infiltration of meltwater when active layer thickness was thin due to predominantly frozen soils in the morning with low temperatures during the cold summer period. Therefore, diel variations in the isotopic compositions of snowmelt were clearly observed during that period. During the warm period, the large amounts of snowmelt were recharged with groundwater due to the thickened active layer, and the soil layer was fully saturated, resulting in increased runoff as streamflow increased. During these periods, diel variations in the isotopic compositions of snowmelt were not distinct and disappeared because the amplitude of diel variation in air temperature was low and persist in high streamflow. Our findings will help to improve the understanding of water source inputs and hydrologic pathways of meltwater in polar catchments.