• 한국물환경학회지
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• 제23권6호
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• pp.843-849
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• 2007

Monitoring of NOM characteristics is important for improving removal efficiency of natural organic matter (NOM) in water treatment processes. In this study, several NOM characteristics, which include specific UV absorbance (SUVA), total carbonate content, molecular weight distribution, and fluorescence properties, were measured using samples collected from a pilot-scale water treatment plant consisting of coagulation/flocculation (C/F), filtration, ozonation and granular activated carbon (GAC) processes. The highest removal of NOM was observed in C/F and filtration processes as demonstrated by the reduction of dissolved organic carbon (DOC) by 25% and 21%, respectively. Despite nearly no change in DOC, however, the lowest SUVA value and the highest total carbohydrate content were observed in the sample from ozonation process. This indicates that non-degradable aromatic compounds become depleted and biodegradable organic compounds are enriched during the process. Comparison of synchronous fluorescence spectra of the samples showed that ozoation process increased protein-like fluorescence while it decreased fulvic-like and terrestrial humic-like fluorescence. Consistently, a slight peak of protein-like fluorescence was observed in the sample from ozonation process. The greatest change in molecular weight distributions of the samples was observed in C/F process. Comparison of size exclusion chromatogram of the samples revealed that NOM fractions with the molecular weight greater than 2000 Da were reduced by over 90% after C/F process. SUVA values and total carbohydrate content of the samples were well correlated with a ratio of protein-like fluorescence and terrestrial humic-like fluorescence intensities with the correlation coefficients of 0.99 and 0.91, respectively. This suggests that synchronous fluorescence properties of NOM could be used as useful tolls for monitoring changes of some NOM characteristics during water treatment processes.

• 미생물학회지
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• 제35권1호
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• pp.41-46
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• 1999

수계에 분포하는 장바이러스를 검출하기 위해 민감도가 높고 검출시간이 빠른 PCR법을 이용하였다. 바이러스입자를 보다 순수하게 농축하기 위해 몇 가지 바이러스농축법을 비교조사하고 그것의 변형을 통하여 개선된 방법을 확립하였다. 비교한 농축방법중 흡탈착/Polyethyleneglycol(PEG) 침전법과 플록화/촉속원심분리법을 통해 10 PFU $ml^{-1}$ 까지 검출이 가능하여 다른 방법에 비해 효과적임이 판명되어Te. Sephadex resin을 이용한 부가적인 시료정제 과정을 통해 시료의 순도를 높일 수 있어검출한계를 10배정도 낮추었다. 서정된 검출법을 통해 한강수계에서 장바이러스의 분포를 조사한 결과 조사한 시료중 한강의 지천에서는 75%, 본류에서는 20%의 시료에서 바이러스가 검출되었다. 본 조사결과 흡탈착/PEG 침전법-PCR 검출기법이 수계의 바이러스 오염도를 간편하고 신속하게 검출하는데 매우 유용하였으며 국내 수계에도 바이러스 오염이 광범위함을 확인하였다.

• 공업화학
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• 제19권4호
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• pp.370-375
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• 2008

비수계 분산(NAD : non-aqueous dispersion) 중합을 이용하여 친환경적인 아크릴 수지를 합성시 최적의 중합조건에 대해 연구하였다. 중합된 고분자 입자들 간의 응집을 방지하기 위한 안정제의 적정량은 20 wt%로 나타났고 안정된 NAD 상태를 유지하기 위한 혼합 용매의 적정 혼합비는 지방족과 방향족 용매의 비율이 80 : 20인 것으로 나타났다. NAD 수지의 점도는 반응시간뿐만 아니라 개시제의 양 및 교반 속도 등에 의해 영향을 받는 것으로 나타났다. 또한 NAD 수지의 입자 크기 및 분포도, 안정제의 양, 개시제의 농도 등에 의해 영향을 받는 것을 확인하였다. 단량체의 투입시기는 단량체를 초기에 모두 투입하면 용매의 극성이 증가하여 입자의 크기가 커져서 입자의 안정성이 저하되므로 단계별로 지속적으로 투입할 필요가 있는 것으로 관찰되었다.

• 한국지반신소재학회논문집
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• 제12권3호
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• pp.87-94
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• 2013

최근 국내의 준설퇴적오니 오염문제가 부각되고 있으며, 이에 따라 퇴적오니 오염의 정화를 위한 기술의 필요성이 증대되고 있다. 국내에서는 준설퇴적물에 응집제를 투입하여 응집 침전 후 탈수하여 매립하고 있으나, 과도한 슬러지 발생과 운송비 부담 등으로 경제성이 떨어져 새로운 처리방법의 필요성이 대두되고 있다. 이에 본 연구에서는 준설퇴적물 내 오염물질은 큰 입자에 비하여 작은 입자에 강하게 흡착되어 있어 입자별로 분리하면 처분량 및 처분비용을 감소시킬 수 있고, 후속처리 공정에 효율적인 하이드로사이클론을 통한 전처리기술을 이용하여 준설퇴적물 처리의 적합성을 파악하였다. 즉, 준설퇴적물의 입자분리를 위하여 하이드로사이클론을 운전한 결과 고형물함량과 유입압력이 분리효율에 큰 영향을 미쳤다.

• 상하수도학회지
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• 제8권2호
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• pp.43-52
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• 1994

In this paper, the unit processes in the typical water treatment plant, which need to be expanded because the water demand is over the existing water treatment capacity in the near future, were carefully examined to upgrade the water treatment plant. The models were installed in the fields as a distorted model based upon the hydraulic similitudes. The models having the constant discharge ratio in the unit processes between the model and the prototype were installed as two units to compare the treatment efficiencies. The capacity of the individual unit, which is a model of the prototype of $250,000m^3/day$ capacity, was $24m^3/day$. In the mixing and flocculation experiments, the mixing intensity of flocculators G was selected as the main experimental item. The optimal mixing intensities G, which are 65/sec for experimental discharge of $1m^3/hr$ and 85/sec for experimental discharge of $1.3m^3/hr$, are identified based upon the comparison the relative turbidity removal efficiencies. Also, the outlet weir loading was selected as the main experimental item in the sedimentation process. Through the continuous experiments with the main experimental items of the mixing intensity of flocculators G and the outlet loading of the weir in the sedimentation basin, about 20% upgrading compared to the existing water treatment capacity was obtained.

• 한국수산과학회지
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• 제36권6호
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• pp.716-722
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• 2003

This study determined the optimum dosage for coagulation reactions of red tide organisms (RTO) using a combination of ignited oyster shell powder (10sp) and loess and examined the electrokinetic and rheological characteristics of their flocs. Two kinds of RTO, Cylindrotheca closterium and Skeletonema costatum, were sampled in Masan Bay and cultured in the laboratory. Coagulation experiments were conducted using various concentrations of IOSP, loess, IOSP+1oess, RTO, and a jar tester RTO cell numbers were counted for both the supernatant and RTO culture solution. The removal rates increased rapidly with increasing IOSP concentrations up to 50 mg/L and loess concentrations up to 800 mg/L. A removal rate of $100\%$ was reached at 400 mg/L of IOSP and 6,400 mg/L of loess. The highest increment $(16.7\%)$ of the rates of coagulation reaction occurred using both IOSP and loess (50+200 mg/L) in comparison with IOSP alone. The rate of coagulation reaction using both IOSP and loess (50+200 mg/L), $90.6\%,$ was similar to employing either IOSP of 150 mg/L or loess of 3,200 mg/L. All of the coagulation liquids for RTO, IOSP (200 mg/L), loess (200 ma/L), and IOSP+1oess (200+200 mg/L) revealed non-Newtonian fluid properties and therefore their shear rate vs. shear stress curves were non-linear. The coagulation liquids revealed elastic body properties at a lower shear rate increasing in the following order: RTO, IOSP (200 mg/L), loess (200 mg/L), and IOSP+1oess (200+200 mg/L. IOSP+1oess (200+200 mg/L) especially demonstrated plastic flow properties at a lower shear rate.

• 한국건축시공학회지
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• 제18권1호
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• pp.51-57
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• 2018

이 연구의 목적은 친수성 표면개질의 에어로겔을 활용한 높은 단열 콘크리트 재료 개발의 기초 평가이다. 시멘트계 재료에서 에어로겔의 재료분리 방지 및 분산성 향상을 위하여 소수성 에어로겔의 표면은 계면활성제를 이용하여 친수성을 부여하였다. 시멘트 페이스트에서 에어로겔의 첨가양은 시멘트 부피 대비 0%에서 100%로 변화하였다. 일부 시멘트 페이스트는 배합단계에서 재료분리 및 에어로겔의 뭉침현상이 나타났다. 에어로겔의 혼입은 시멘트 페이스트의 압축강도를 저하시키는 반면 열전도율은 향상시켰다. 에어로겔을 100% 첨가한 페이스트의 열전도율은 일반 페이스트 대비 약 43% 낮았다. 에어로겔 혼입 콘크리트의 압축강도와 단열성 향상을 위해서는 에어로겔의 최적 표면개질에 대한 연구가 요구되었다.

• 방사성폐기물학회지
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• 제16권2호
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• pp.173-182
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• 2018

원자력 시설 내 방사능을 포함하는 물질의 제염을 위한 방법 중 거품제염은 2차폐기기물의 양을 저감시킬 수 있는 장점을 지니고 있다. 본 연구에서는 거품안정성을 증가시킬 수 있는 실리카 나노입자를 여러가지 조건을 달리하여 합성하였다. Cetyltrimethylammonium bromide(CTAB)는 거품제염제의 거품안정성에 많은 영향을 나타내었다. 이러한 거품안정성이 향상된 이유는 제염제 내에 공기와 용액간의 계면에서 실리카 나노입자와 계면활성제의 반응으로 생각된다. 또한, CTAB는 실리카나노입자의 분리특성에서도 우수한 성능을 나타냈었다. 실리카 나노입자 분리시, CTAB의 탄화수소기에 의한 소수성과 전하중성화에 의해서 실리카 나노입자의 응집현상을 향상시켰다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2000년도 제26회 펄프종이기술 국제세미나
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• pp.1-10
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• 2000

The development of paper machines, increasing machine speeds with new, mostly low basis weight and/or high ash content paper grades, as well as the fact that several trends regarding process items have increased the sensitivity of papermaking. At the same time, papermakers are looking for flexibility in the production line. We can say that with all PMs the biggest benefits with the lowest capital spending can be achieved by focusing on improved wet end management. In order to manage wet end chemistry on a paper machine, our goal is to control sub-process through which we can influence the operation of the entire wet end with maximum effect. Key measurements and controls are-white water consistency control which is the most effective way to control retention - charge demand measurement and control which takes care of concentration of the anionic material entering to PM -ash measurements and controls which are deeply related to retention and paper quality This paper presents and concentrates to two of these key controls ; retention and charge. The purpose of charge control is to give the process control the tools to react to changes caused by amount of dissolved and colloida material incoming to wet end system. It is called coagulation or fixing control. Retention control is then taking care of retention aid flow to the process by responding any changes seen in white water consistency. It is called flocculation control. Each of these solutions separately , and even more effectively all together, stabilize the wet end operations and so greatly improve the produced paper quality and machine runnability. Practical results will be presented and they are referring to the latest mill cases. We have developed the first wet end measuring system in the late 1980s and control solutions based on this modern measuring technology were completely updated in 1990s. This paper introduces the principle, operation , and results of our unique wet end analyzers (retention and charge ) which are at the level of automation solutions as a part of paper machine quality control Especially our newest member of the platform , on-line charge analyzer has reached and set new standards to the on-line charge monitoring.

• 펄프종이기술
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• 제32권5호
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• pp.44-53
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• 2000

The development of paper machines, increasing machine speeds with new, mostly low basis weight and/or high ash content paper grades, as well as the fact that several trends regarding process items have increased the sensitivity of papermaking. At the same time, papermakers are looking for flexibility in the production line. We can say that with all PMs, the biggest benefits with the lowest capital spending can be achieved by focusing on improved wet end management. In order to manage wet end chemistry on a paper machine, our goal is to control subprocesses through which we can influence the operation of the entire wet end with maximum effect. Key measurements and controls are - white water consistency control which is the most effective way to control retention. - charge demand measurement and control which takes care of concentration of the anionic material entering to PM. - ash measurements and controls which are deeply related to retention and paper quality. This paper presents and concentrates to two of these key controls: retention and charge. The purpose of charge control is to give the process control the tools to react to changes caused by amount of dissolved and colloidal material incoming to wet end system. It is called coagulation or fixing control. Retention control is then taking care of retention aid flow to the process by responding any changes seen in white water consistency. It is called flocculation control. Each of these solutions separately, and even more effectively all together, stabilize the wet end operations and so greatly improve the produced paper quality and machine runnability. Practical results will be presented and they are referring to the latest mill cases. We have developed the first wet end measuring system in the late 1980s and control solutions based on this modern measuring technology were completely updated in 1990s. This paper introduces the principle, operation, and results of our unique wet end analyzers (retention and charge) which are at the level of automation solutions as a part of paper machine quality control. Especially our newest member of the platform, on-line charge analyzer has reached and set new standards to the on-line charge monitoring.