• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2295-2298
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• 2014

To effectively destruct 2-chlorophenol, a representative sterile preservative, nanometer-sized Mn (0.5, 1.0, 3.0 mol %)-incorporated $TiO_2$ powders were synthesized by a solvothermal method. XRD result demonstrated that the Mn ingredients were perfectly inserted into $TiO_2$ framework. The Mn-$TiO_2$ particles exhibited an anatase structure with a particle size of below 20 nm. The absorbance was shifted to the higher wavelength on Mn-$TiO_2$ compared to that of $TiO_2$. Otherwise, the PL intensities which has a close relationship for recombination between holes and electrons significantly decreased on Mn-$TiO_2$. The photodecomposition for 2-chlorophenol in a liquid system was enhanced over Mn-doped $TiO_2$ compared with pure $TiO_2$: 2-chlorophenol of 50 ppm was completely decomposed after 12 h when 1.0 mol % Mn-$TiO_2$ was used. Consequently, the core of this paper is as follows. introducing Mn into $TiO_2$ framework reduced the band-gap, moreover, it played as an electron capture resulted to lower recombination between electrons and holes during photocatalytic reaction for removal of 2-cholophenol.

• 환경영향평가
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• 제21권6호
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• pp.917-925
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• 2012

In this study, we report the runoff characteristics of pollutants for Tamjin A and B watershed in Tamjin river basin using statistical analysis, such as correlation analysis and regression equation. Flow rate and water qualtiy data collected from 2 sampling sites(Tamjin A and B watershed) during 3 years(2009~2011) were analyzed for biochemical oxygen demand(BOD), total nitorgen(TN), total phosphorus(TP) and suspended solid(SS). The results showed that strong correlations were observed between flow rate and SS in Tamjin A, while weak correlations were observed among the BOD, TN, and TP. In Tamjin B, strong correlations were observed among the flow rate, SS and T-P except BOD and TP. Meanwhile, the values of $R^2$ for regression equations between flow rate and pollutants load were greater than 0.7. Results of these statistics indicated that there was a good agreement between flow rate and pollutants load. Also, the flow rate exponents of regression equations for BOD, TN, and TP were smaller than 1 in Tamjin A. In Tamjin B, flow rate exponents of regression equation for BOD and TP were smaller than 1. These results indicated that concentrations of BOD, TN, TP in Tamjin A and concentrations of BOD and TP were decreased as the flow rate was increased. This means that rater than nonpoint sources, point sources affect BOD, TN and TP in Tamjin A and BOD and TP in Tamjin B.

• Ocean and Polar Research
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• 제31권1호
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• pp.71-76
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• 2009

Drastic changes in the water quality and phytoplankton community of the new Saemankeum Lakeduring the first decade following the construction of the Saemankeum Sea Wall has been considered to be unavoidable. Input of eutrophicated water through the Mankyeong River and Dongjin River might produce more direct effects on the water quality and phytoplankton community, which lead us to launch a long-term semi-weekly investigation at the "Mankyeong Bridge" monitoring point to resolve its short-term effect as well as long-term stabilization of the ecosystem in the new Saemankeum Lake. During 15 months starting from June 2006, the water temperature varied in accordance with the typical seasonal variations in temperate on the coasts, and no significant daily variations evoked by tidal cycle could be detected. However, there was an inverse relationship between seasonal precipitation and salinity even though the range in annual variation was drastically reduced right after the construction of the Saemankeum Sea Wall. Species richness in the phytoplankton community was also reduced due to the narrowed annual range of salinity, which would eliminate the mid-high salinity species from the Mankyeong Bridge monitoring point. Similarly, species diversity was decreased with increased dominance of the phytoplankton community after the construction. Between the two summer seasons during the present study, species diversity was higher in 2007 than in 2006, which might indicate the early stage of a gradual stabilization in the ecosystem including the phytoplankton community at the monitoring station. The phytoplankton community thus needs to be monitored on a long-term basis to identify indirect signals that can be used to assess the stability of the ecosystem in the young Saemankeum Lake.

• 한국건설관리학회논문집
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• 제17권1호
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• pp.40-47
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• 2016

현재 우리나라의 대다수 공공하수처리시설들은 미래의 하수량 증가에 따른 설계기준에 대한 대비가 부족하여 현재 시설로는 향후 계획하수량의 적정처리가 곤란할 것으로 판단된다. 이에 대응하여 정부는 하수처리장 건설 사업을 꾸준히 진행하고 있는 추세다. 앞으로 건설될 하수처리시설의 효율적인 운영과 시설물의 가치 향상을 위해 본 연구에서는 주민과 하수처리시설, 토목 시공, 설계VE 전문가들을 대상으로 설문조사를 실시하였다. 이를 바탕으로 비용 절감 뿐 아니라 시설물의 성능향상, 이용자 및 인근 주민의 만족도 등을 반영한 성능평가항목을 도출하고, 다단계성능평가법을 이용하여 효율적인 설계VE 수행을 위한 보다 객관적인 성능평가 항목의 가중치 분석을 실시하였다

• Ocean and Polar Research
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• 제28권3호
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• pp.293-303
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• 2006

The topography of the sea floor and textural characteristics of surface sediments are documented in areas off sectors 1,2, and 4 of the Saemangeum dyke and inside the dyke. These were investigated during the years 2002 to 2005, when the dyke construction almost came to an end, and were compared with natural topographic analogs before the dyke construction from the maritime maps of 1982 and 1994. Along and across the dyke are a number of erosional troughs formed by intensified currents during the dyke construction. The sea floor off sector 4 has undergone gradual accumulation of sands moving from the north by currents varying in direction from normal to parallel to the dyke. This is in a strong contrast with a slight erosional environment prevailing over the sea floor before dyke construction. off sectors 1 and 2, a topography with an alterative pattern of erosional troughs and sand shoals develops normal to the dyke. Eroded materials from the troughs seem to have added to the sand shoals. As a result, the troughs, former natural tidal channels, have become increasingly deeper, whereas the sand shoals have become somewhat shallower. The sea floor inside the dyke has also been remarkably shallower with expanding tidal flats due to trapping by the dyke of continuous sediment input from the Dongjin and Mangyeong rivers. Sands, all of which are considered to have originated originally from the two rivers, dominate the entire Saemangeum area.

• 멤브레인
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• 제27권1호
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• pp.104-107
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• 2017

역삼투막 운영에 있어서 유기물 오염에 대한 문제들을 해결하기 위해 많은 연구를 하고 있다. 현재 가성소다(NaOH)를 사용하여 유기물 오염 제거를 하고 있다. 본 연구는 지속적인 막오염 증가 문제를 해결하기 위한 물리/화학적 세정 기법으로서 기존에 사용하던 가성소다와 Micro-bubble를 이용하여 유기물 오염 제거 실험을 수행되었다. 멤브레인 강제 오염을 위해 Humic acid sodium, Bovine serum albumin, Sodium alginate 약품을 사용하여 유기물 오염을 시켰다. 유기물 오염에 따른 Flux를 관찰하였고, 가성소다와 Micro-bubble를 이용한 유기물 오염 제거 실험은 가성소다로만 사용했을 때보다 향상된 것을 관찰했다.

• 대한안전경영과학회지
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• 제14권1호
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• pp.155-165
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• 2012

This essay talks about research of robust design for quality improvement of production procedure of Wet Etchant. It suggested the optimum design method in consideration of specific capability value that is the way to maximize the quality of product in the production system by using Daguchi parameter design method while finding factors affecting product quality with analysis of production system of product A from producer D. Also, it set long term of 6months as noise factor and let it to be the robust design that can find the optimum condition of control factor that is dull to the changes of each month, that is the change in noise factor. The control factor which affects the product quality is decided as combination method, temperature of raw material, combination time and as there are too many possibilities for combination methods, we performed 4 methods first based on previous research data then derived three ways with product that passed SPEC and set as the factor. As a result of application of optimum production procedure suggested in this essay to the actual production process with its standardization, there was a effect of drop of more than 10particles in comparison to the particle number of previous product and also it brought the effect that resulted the stable number of particle of under 30 that is what the client company suggested.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.372-378
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• 2018

Life management technology is required as the failure risk of aged power transformers increases. Asset management technology is developed to evaluate the remaining life, establish the replacement strategies, and decide the optimal investment based on the reliability and economy of power transformers. The remaining life assessment uses data such as installation, operation, maintenance, refurbishment, and failure of power transformers. The optimal investment also uses data such as maintenance, outage, and social costs. To develop the asset management system for power transformers, determining the degradation parameters related to the aging of power transformers and evaluating the condition of power transformers using these parameters are important. In this study, since 1983, 110,000 Dissolved Gas Analysis (DGA) data have been analyzed to determine the degradation parameters related to the aging of power transformers. The alarm rates of combustible gases ($H_2$, $C_2H_2$, $C_2H_4$, $CH_4$, and $C_2H_6$), TCG, CO, and $CO_2$ were analyzed. The end of life and failure rate (bathtub curve) of power transformers were also calculated based on the failure data from 1981 to 2014. The DGA gases related to discharge, overheating, and insulation degradation were determined based on alarm and failure rates. $C_2H_2$, $C_2H_6$, and $CO_2$ were discharge, oxidation, and insulation degradation parameters related to the aging of power transformers.

• 농약과학회지
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• 제6권3호
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• pp.202-208
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• 2002

피에서 분리한 Fusarium oxysporum균주로부터 여러 번의 chromatography를 통하여 좀개구리밥의 생장을 억제하는 물질을 분리하였다. 질량분석과 핵자기공명분석을 통하여 이 물질은 dehydrofusaric acid로 동정되었다. Dehydrofusaric acid는 좀개구리밥의 생장에 대한 $EC_{50}$ 값이 $1.5{\mu}g/ml$로 매우 활성이 높은 것으로 나타났다. 또한 이 물질은 식용피, cress, 강피 및 동진벼의 뿌리의 생장도 억제하였으나, 식용피와 cress의 발아 및 네 가지 식물의 지상부의 생장에는 전혀 영향을 주지 않았다.

• 식물조직배양학회지
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• 제28권2호
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• pp.97-101
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• 2001

동화산물의 분배 효율 개선을 통한 생산성 향상 가능성을 조사하고자 감자의 sucrose 수송자 유전자를 벼에 형질전환 하였다. 동진벼로부터 유도된 callus를 감자의 sucrose 수송자 유전자가 도입된 A. tumefaciens LBA 4404와 공동배양한 후, 선발배지에서 증식된 callus를 250 mg/L carbenicillin, 2 mg/L kinetin, 0.1 mg/L NAA가 첨가된 MS 배지에 옮겨 약2주 후부터 소식물체를 얻었다. Carbenicillin 250 mg/L 첨가된 MS 기본 배지에서 소식물체의 발근을 유도하여 재분화 식물체를 얻었다. 선발된 callus는 약 150%의 높은 식물체 재분화율을 보였다. 재분화 식물체에 대한 PCR 분석을 수행하여 감자의 sucrose수송자 유전자가 삽입된 형질전환 벼 식물체를 선발하였다. 선발된 형질전환 식물체에 대한 Southern blot 분석을 통하여 외래유전자인 감질 sucrose 수송자 유전자가 벼 genome 내에 안정적으로 도입되었음을 확인하였다.