• 한국지하수토양환경학회지:지하수토양환경
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• 제24권6호
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• pp.26-32
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• 2019

An analysis of groundwater quality is significant for monitoring and managing water contamination and groundwater system. For the purpose of those, the geochemical characteristics of groundwater were studied over the concern for water quality, water type and origin of nitrate nitrogen. Total colony counts were detected in 11 out of 20 samples, and the average value was 31.73 CFU/ml. Range and average of NO₃-N concentrations were 0.9~24.0 mg/L and 8.3 mg/L. All groundwater types were found to be Ca²⁺-HCO₃^-. The range and average of NO₃-N were 0.2~17.4 mg/L and 8.7 mg/L, and those of δ¹⁵N were 1.7~8.9‰, and 5.0‰. Careful consideration is required for evaluating the origin of nitrogen when NO₃-N concentration is low. In general, noticeable difference between rockbed and alluvial water was not found. The ranges of nitrate origins by chemical fertilizer, livestock manure and domestic sewage, and natural soil were 29.6~76.4%, 14.2~58.9% and 2.6~7.0%, and the average values of those were 57.4%, 37.4%, and 5.3%, respectively. Origin of nitrate was affected by more chemical fertilizer than the other parameters. Rockbed water was more affected by chemical fertilizer than alluvial water.

• Current Photovoltaic Research
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• 제6권2호
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• pp.49-55
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• 2018

Recently solar cell industry needs the optimal design of Czochralski process for low cost high quality silicon mono crystalline ingot. Because market needs both high efficient solar cell and similar cost with multi-crystalline Si ingot. For cost reduction in Czochralski process, first of all energy reduction should be completed because Czochralski process is high energy consumption process. For this purpose we studied optimal water-cooling tube design and simultaneously we also check the quality of ingot with Von mises stress and V(pull speed of ingot)/G(temperature gradient to the crystallization) values. At this research we used $CG-Sim^{(R)}$ S/W package and finally we got improved water-cooling tube design than normally used process in present industry. The optimal water-cooling tube length should be 200mm. The result will be adopted at real industry.

• 한국환경과학회지
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• 제21권9호
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• pp.1115-1129
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• 2012

The objective of this study was to analyze long-term annual and seasonal trends of water chemistry on landuse patterns and seasonal precipitation using 72 sampling sites within Namhan River watershed during 2001-2010. Water quality, based on multi-parameters of water temperature(WT), dissolved oxygen(DO), biochemical oxygen demand(BOD), chemical oxygen demand(COD), suspended solids(SS), total nitrogen(TN), total phosphorus(TP), and electric conductivity(EC) varied largely depending on monsoon rain and landuse patterns such as forest, cropland, and residence. Concentrations of BOD and COD as an indicator for organic matter pollution, increased during summer monsoon season at the cropland and residential streams. Values of TN and TP were higher in residential streams than in the forest and cropland streams. In the meantime, DO values had weak relations to the landuse patterns of forest and cropland cover. Water quality was worst in cropland and residential streams, and also most degradated in 4th order streams. Overall, our results suggest that efficient water quality management is required in the cropland and residential landuse streams.

• Advances in environmental research
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• 제6권1호
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• pp.53-65
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• 2017

Assessment of seasonal changes in surface water quality is an important aspect for evaluating temporal variations of river pollution due to natural or anthropogenic inputs of point and non-point sources. In this study, surface water quality data for 15 physico-chemical parameters collected from 7 monitoring stations in a river during the years from 2014 to 2016 were analyzed. The principal component analysis technique was employed to evaluate the seasonal correlations of water quality parameters, while the principal factor analysis technique was used to extract the parameters that are most important in assessing seasonal variations of river water quality. Analysis shows that a parameter that is most important in contributing to water quality variation for one season may not be important for another season except alkalinity, which is always the most important parameters in contributing to water quality variations for all three seasons.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.612-615
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• 2007

Water quality modelling is an ideal tool of simulating physical, chemical and biological changes occurring in water systems. It has been utilized in a number of GIS-based water quality management and analysis applications. However, there is a need of a decision making process to translate the modelling result into an understandable form thereby implement the modelling results to the real world. This paper outlines a new water quality index called the QUAL2E's water quality index (QWQI) based on the water quality modelling using QUAL2E. The development mainly includes four steps: variable selection, sub-index development, weight assignment and sub-index aggregation. An experiment of applying the index and GIS to the Sapgyo River in Korea was implemented. Different from other water quality indices for general water uses, the index is specifically used for the simulated water quality indicators. The index can provide a simple and easy-to-understand decision support. Furthermore, interfacing with GIS, the decision analysis can be performed within a spatial environment. However, more study needs to be made in the future including the improvement of aggregation function.

• 환경위생공학
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• 제15권1호
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• pp.88-94
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• 2000

The purpose of this study was to analyze and compare the contents of minerals and ionic components in domestic commercial natural mineral waters, and to investigate the relationship between water quality and characteristics of suspended and rocks there of its source. All mineral waters tested in this study met the korean mineral water quality guideline, although chemical components varied widely depending upon the geological characteristics and degree of urbanization of the source area or physical water treatment method. The water quality of commercial bottled water was different from that of source water, especially in cationic components, and showed a tendency to become worse with time elapsed. The water quality on the bottle was also different from the measured quality.

• 대한지리학회지
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• 제39권4호
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• pp.544-561
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• 2004

본 연구에서는 대관령 지역의 산림 및 농경지 소유역을 대상으로 주 1회의 유량 및 수질 조사를 실시하고 유량 및 수질 항목간의 상관관계를 분석하였다. 산림 소유역의 수질 변화는 적었던 반면 농경지 소유역에서는 화학비료 및 가축분 퇴비의 시용과 토양 유실로 인해 큰 폭의 수질 변화를 보였다. 용존산소량(DO)은 두 소유역에서 유량보다는 수온과 매우 뚜렷한 음의 상관관계를 나타냈다. 산림 소유역에서는 농경지 소유역에 비해 유량과 총질소(T-N) 및 $K^{+}$의 양의 상관관계가 뚜렷하게 나타났다. 반면, 농경지 소유역에서는 부유물질 총량(TSS), 총인(T-P) 및 화학적 산소요구량(COD)이 유량과 높은 상관성을 보였다. 대관령 지역에서는 도암호의 수질 오염, 특히 T-P의 증가가 심각하다는 점에 비추어 볼 때 수질 개선을 위해서는 농경지의 토양 유실 방지가 매우 중요하다. 특히 고랭지 채소 파종기에 해당하는 6월말에서 7월초에 이르는 기간의 토양 및 양분유실이 가장 심각한 것으로 나타나 이를 줄이기 위한 친환경농법 도입이 요구된다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.441-444
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• 2002

In recent, industrialization increases the level of pollution load in sea areas, and the inflows of pollutants to public sea areas cause sudden and wide-range of influence to the water quality and the ecosystem. To prepare for these kinds of unpredictable water pollution issues, the necessity is emerging to build an automatic water quality monitoring system, which can monitor and alarm the water quality changes of the subject sea areas. For the ongoing installation plan of the automatic water quality monitoring system around the Saemankeum sea area, this report compares and analyzes its installation conditions as well as the physical and chemical characteristics of the in-situ type and the water-sampling type of the automatic water quality monitoring equipments, and subjects to provide elementary data for the system installation in the Saemankeum.

• 생태와환경
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• 제42권4호
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• pp.422-431
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• 2009

This study was to provide basic data for aquatic ecosystem research using fishes. Field sampling was carried out at five selected sites of Gap Stream, and fish samples, especially for a selection of sentinel species were collected three times in June, September, and October 2007. We analyzed total length distribution of Zacco platypus in relation with the season and the sampling sites, and then compared with total body weight, condition factor (K), and age distribution of the fish. The fish population data were compared with physico-chemical water quality, obtained from the Ministry of Environment, Korea. Water quality analysis showed a significant nutrient enrichment, based on total nitrogen (TN) and total phosphorus (TP), and organic matter pollution, based on biological oxygen demand (BOD) and chemical oxygen demand (COD) in the Site 5, which is directly influenced by wastewater disposal plant (WDP). Population analysis of the sentinel species showed that the total number of individuals, age distribution, and the population size-structure were influenced by the effluents from the WDP, and that reproductive failure of young-age population were evident in Site 5. According to the relation analysis of total weight to K, the disturbed population was mainly attributed to combined effects of habitat modifications and chemical degradations. Regression analysis of K values against water quality parameters showed significant (p<0.05) positive relations with nutrient and organic matter contents. Our data suggest that the population structure using a sentinel fish species reflected the ambient water quality in the stream and that diagnosis of aquatic ecosystem health using Z. platypus population may be practical for water resource and ecosystem conservations.

• 콘크리트학회지
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• 제10권4호
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• pp.205-212
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• 1998

레미콘을 제조하는 배쳐플랜트에는 혼화제를 저장하는 저장탱크가 설치되어 있는데, 특히 기온이 $0^{\circ}C$이하로 저하하는 겨울철에는 혼화제 저장탱크내의 혼화제가 동결할 수 있어 설비보존 목적상 동결온도의 검토가 요구되고 또한 동결된 혼화제를 이용할 경우 레미콘의 품질 변화가 초래될 수 있는지 검토가 요구되지만 국내의 경우 연구보고나 규정은 마련되어 있지 않은 실정이다. 그러므로 본 연구에서는 본 연구에서는 국내에 유통되고 있는 콘크리트용 각종 화학혼화제를 무작위로 시료채취하여 동결온도를 측정하므로써 동절기 외기에 노출된 혼화제 투입설비에 대한 적정 보온대책의 제안 및 레미콘에서 반드시 사용되어지는 AE제 및 AE감수제 등의 혼화제를 대상으로 동결전과 동결융해를 반복한 혼화제를 사용한 콘크리트의 품질변화에대하여 실험연구를 실시하였다. 연구결과 방동제, AE감수제 촉진형 등 내한성 혼화제를 제외한 대부분의 혼화제는 제주도 및 일부 남부 지방을 제외한 한국의 겨울철 외기온 조건하에서는 혼화제의 동결위험성이 있으므로 보온조치가 필요할 것으로 판단되며, 동결된 혼화제를 사용할 경우의 콘크리트 품질변화는 교반을 충분히 하여 이용한다면 슬럼프, 공기량, 강도 등에서 크게 문제시 되지 않는 것으로 분석되었다.