• 한국농공학회지
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• 제24권1호
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• pp.44-52
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• 1982

Recently, estuary reserovoirs have been actively constructed in Korea and also in Japan there are a large number of estuary reservoirs constructed. But most of the estuary reservoirs are located at the downstream of a river where geographical condition is best for the construction of an enclosing dam. And an effective utilization of water from the estuary reservoir seems to be difficult even if estuary reservoirs are considered to be the water resources the most available for their watershed. Studies on estuary reservoirs so far have been mainly concentrated on the physical and engineering problems of the dam construction itself. The purpose of the present study is to review the estuary reservoir planning in connection with the water resources development and to study a basis of the planning. First, the levels of water use in Korea and Japan were compared with those of other countries in the world. And then, some representative reservoirs were selected to study the roles of a reservoir and water-using conditions in the watershed. Based on the study, a survey was given on the relation between a dam construction upstream and an estuary reservoir construction downstream of a river. Finally, a comprehensive examination was made of the bases of estuary reservoir planning. (1) The estuary reservoir planning is deeply related to the plan for water use develo- pment in the watershed. After the upstream water resources were fully developed up to the most, water reso- urces development by an estuary reservoir should be started. (2) If an estuary lake has a capacity big enough, it can store flood discharge of the watershed without any loss and become a basic facility that will bring about the maxi- mum use of water from the watershed. (3) Estuary reservoirs store water used in the upstream watershed, so recycling of water use is attained by the reservoir. Water in the estuary lake is difficult to be fresh water in its long run. Therefore, estuary reservoir should be located at a place where polluted water is purified and refused. All the planning should be based on the assumption that water in the estuary lake is not fresh but polluted after a long time. (4) The estuary lake can only supply water to the lower basin directly. But the upstream area is benefited from the estuary lake by exchange of irrigation water sources between the lower and the upper area. So a large-scale exchange plan between new and existing water resources is important. By constructing estuary reservoirs and the exchange of water sources between upper and lower areas, the reasonable maximum use of water from the whole watershed is at- tained. (5) The big problem coming from the water resources development by an enclosing estuary is salt water intrusion into the lake. To maintain the estuary lake salt-free, multi-purpose use of the lake should be avoided. It is necessary to take such fundamental measures as abolition of back flow operation of gate, and the closing of the fish port and the fish ladder. The results mentioned above were found in this study and these results of this study could be used for the adequate planning of estuary reservoirs in connection with the maximum water use of the watershed.

• 한국환경과학회지
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• 제8권3호
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• pp.411-417
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• 1999

The interfacial chemical behavior, lattice exchange and dissolution, of $FeS_{(S)}$ as one of the important sulfide minerals was studied. Emphases were made on the surface characterization of hydrous $FeS_{(S)}$, the lattice exchange of Cu(II) and $FeS_{(S)}$, and its effect on the dissolution of $FeS_{(S)}$, and also affect some organic ligands on that of both Cu(II) and $FeS_{(S)}$. Cu(II) which has lower sulfide solubility in water than $FeS_{(S)}$ undergoes the lattice exchange reaction when Cu(II) ion contacts $FeS_{(S)}$ in the aqueous phase. For heavy metals which have higher sulfide solubilities in water than $FeS_{(S)}$, these metal ions were adsorbed on the surface of $FeS_{(S)}$. Such a reaction was interpreted by the solid solution formation theory. Phthalic acid(a weak chelate agent) and EDTA(a strong chelate agent) were used to demonstrate the effect of organic lignads on the lattice exchange reaction between Cu(II) and $FeS_{(S)}$. The $pH_{zpc}$ of $FeS_{(S)}$ is 7 and the effect of ionic strength is not showed. It can be expected that phthalic acid has little effect on the lattice exchange reaction between Cu(II) and $FeS_{(S)}$. whereas EDTA has very decreased the removal of Cu(II) and $FeS_{(S)}$. This study shows that stability of sulfide sediments was predicted by its solubility. The pH control of the alkaline-neutralization process to treat heavy metal in wastewater treatment process did not needed. Thereby, it was regarded as an optimal process which could apply to examine a long term stability of marshland closely in the treatment of heavy metal in wastewater released from a disussed mine.

• 공업화학
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• 제28권5호
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• pp.539-546
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• 2017

본 연구는 산성유해가스 제거를 위한 고효율 음이온교환 복합 폼 화학필터를 제조하기 위하여 폴리우레탄(PU) foam에 다른 종류의 PSA를 사용하여 상용이온교환수지를 부착하여 제조, 이의 내수성, 내화학성, 접착신율, 농도와 유속에 따른 HCl과 HF의 흡착특성에 관하여 연구하였다. 그 결과 접착신율은 ATE-701은 900%, AT-4000C는 1,500%, HCA-1000는 2,400%이며, 내수성 및 내화학성평가에서 HCA-1000의 탈리율이 6% 미만으로 우수한 내구성을 가짐을 확인하였다. HCl, HF의 농도와 유속이 증가함에 따라 흡착이 빠르게 일어났으며 유속과 농도에 관계없이 110 min 이후 100% 흡착파과평형이 일어남을 확인할 수 있었다. 또한 SEM Morphology 관찰 결과 점착제가 고르게 분산되어 있고 이온교환수지의 다공구조가 유지되었으며, 흡-탈착 공정에서 성능저하가 없는 것으로 보아 내구성이 있음을 확인하였다.

• 설비공학논문집
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• 제29권1호
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• pp.7-14
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• 2017

This study carried out a numerical analysis of the effects of hot waste water supply on the performance of a Type II absorption heat pump. There are two types of hot waste water supply, regular series flow and reverse series flow. Also it investigated the interaction between each type of flow and heat exchange solutions. As the effectiveness of heat exchange solutions increase, the steam generation and (COP) increase as well. If the effectiveness of a heat exchange solution is lower than 0.566, the steam generation rate of the reverse flow is lower than that of the regular series flow. A high effectiveness of heat exchange solution is therefore required to make a larger amount of steam in reverse series flow than with ordinary series flow. The COP difference between the two types of flow decreases with the increasing effectiveness of the heat exchange solution. Thus, a reverse flow type absorption heat pump can match the high steam generation rate and COP of the ordinary flow type when a highly effective heat exchange solution is applied.

• 공학논문집
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• 제4권1호
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• pp.109-118
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• 2002

본 연구에서는 Na-Mont와 알킬 사슬 말단에 산기를 함유하는 베타인 화합물 $R_{11}SO_4$사이의 양이온 교환반응을 이산화탄소를 함유한 증류수를 사용하는 일반 조건 및 이산화탄소가 제거된 증류수를 이용한 상이한 pH 조건 하에서 수행하고, 그 거동을 살펴보았다. 결과적으로 일반 조건 하에서의 교환반응은 49 시간 후에 완전히 종료되었으며, 교환용액 하에 및 메탄올로 세척한 후와 고진공 하에서 건조한 후의 층간거리로는 $23.6\AA$ 및 17.1과 $15.0\AA$이 각각 얻어졌다. 상이한 pH 값 하에서의 교환반응 후에 pH 값 하에서의 교환반응 후에 pH 교환용액 하에서 얻은 층간거리 값은 pH 값에 상관없이 약 24.7과 $25.6\AA$ 사이에 놓였으며, 시료를 공기 및 고진공 하에서 건조한 후의 층간거리로는 약 $20.0\AA$ 및 13.8~14.4 사이의 값이 각각 얻어졌다.

• 멤브레인
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• 제13권2호
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• pp.118-124
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• 2003

막소재는 투과증발 막공정에서 메탄을 저항체로 잘 알려진 Poly(vinyl alcohol, PVA)과 술폰기가 있는 가교제 sulfo-succinic acid(SSA)를 PVA에 대해 17 wt.%로 고정시켜 제조하였다. 이에 이온교환능력을 향상시키기 위해 양이온교환기가 포함된 poly(acrylic acid, PAA)를 첨가하여 함량변화에 따라 메탄올투과도 (methanol permeability) 특성과 이온전도도(ion conductivity)를 측정하였으며, 기본적인 이온교환막의 특성인 함수율 (water content), 이온교환용량 (ion exchange capacity, IEC) 등을 측정하였다. PAA함량에 따른 메탄을 투과도와 이온전도도 결과는 SSA만을 사용했을 때 보다 전체적으로 감소하는 경향을 나타났는데 이는 PAA의 함량 증가를 통하여 가교도의 증가로 인한 자유부피감소가 카르복실기인 양이온교환기 도입 영향보다 더 크게 작용한 것으로 판단된다 이온전도도와 메탄올투과도의 결과로부터 'vehicle mechanism'이 본 실험에서 제조된 PVA/SSA/PAA막에서 더 우세한 영향을 미쳤을 것이라 사료된다.

• 생명과학회지
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• 제7권2호
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• pp.73-78
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• 1997

시판되고 있는 강염기성 $Cl^{-}$형의 음이온 교환수지를 사용하여 회분식 질산성 질소 제거 실험을 행하여 다음과 같은 결과를 얻었다. 수지의 종류에 따라 제거특성은 달랐다. 수지의 량이 많을수록, 계의 온도가 톡을 수록 질산성 질소이 제거효율은 높아졌다. 원수의 농도는 낮을수로그 원수의 공급유속은 느릴수록 질산성 질소의 제거효율이 좋았다. 음이온에 디한 겔형 이온교환수지인 SA 10A의 선택성은 ${SO_4}^{2-}>{No_3}^->NO_{2-}>{HCO_3}^-$로써 이온가 수가 높은 이온일수록 선택성이 증가하고 은 이온가인 경우에는 원자번호가 클수록 그리고 수화반경이 작을수록 선택성이 증가하였다. 증가하였다.

• 한국환경과학회지
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• 제25권8호
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• pp.1087-1095
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• 2016

The concepts of residence time and flushing time can be used to explain the exchange and transport of water or materials in a coastal sea. The application of these transport time scales are widespread in biological, hydrological, and geochemical studies. The water quality of the system crucially depends on the residence time and flushing time of a particle in the system. In this study, the residence and flushing time in Gamak Bay were calculated using the numerical model, EFDC, which includes a particle tracking module. The average residence time was 55 days in the inner bay, and the flushing time for Gamak Bay was about 44.8 days, according to the simulation. This means that it takes about 2 months for land and aquaculture generated particles to be transported out of Gamak Bay, which can lead to substances accumulating in the bay. These results show the relationships between the transport time scale and physical the properties of the embayment. The findings of this study will improves understanding of the water and material transport processes in Gamak Bay and will be important when assessing the potential impact of coastal development on water quality conditions.

• 한국표면공학회지
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• 제49권2호
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• pp.159-165
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• 2016

The hydrogen has been recognized as a clean, nonpolluting and unlimited energy source that can solve fossil fuel depletion and environmental pollution problems at the same time. Water electrolysis has been the most attractive technology in a way to produce hydrogen because it does not emit any pollutants compared to other method such as natural gas steam reforming and coal gasification etc. In order to improve efficiency and durability of the water electrolysis, comprehensive studies for highly active and stable electrocatalysts have been performed. The platinum group metal (PGM; Pt, Ru, Pd, Rh, etc.) electrocatalysts indicated a higher activity and stability compared with other transition metals in harsh condition such as acid solution. It is necessary to develop inexpensive non-noble metal catalysts such as transition metal oxides because the PGM catalysts is expensive materials with insufficient it's reserves. The optimization of operating parameter and the components is also important factor to develop an efficient water electrolysis cell. In this study, we optimized the operating parameter and components such as the type of AEM and density of gas diffusion layer (GDL) and the temperature/concentration of the electrolyte solution for the anion exchange membrane water electrolysis cell (AEMWEC) with the transition metal oxide alloy anode and cathode electrocatalysts. The maximum current density was $345.8mA/cm^2$ with parameter and component optimization.

• 수산해양기술연구
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• 제19권1호
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• pp.33-39
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• 1983

폐쇄적인 지형구조를 보이는 여자만에서 환경조사 및 어장관리를 위한 해양물리학적 기초자료를 얻기 위하여, 1982년 10월 30일부터 11월 6일까지 만구에서 실시한 측류판추적 및 유속계에 의한 측류자료를 사용하여 해수교류 및 교환량을 추정하고 그 해수교환특성을 알아보았다. 여자만의 평균용적(1.96km super(3))에 대하여 유입량은 43%(조차, 320cm), 유출량은 42%(조차, 304cm)였다. 이로부터 얻은 항류성분은 약 3.7$\times$10 super(7)m super(3)로서 대부분이 담수유출량으로 해석된다. 물질수송에 기여한다고 생각되는 평균해수교환량은 만의 용적(2.33km super(3); 평균고조면 3.1m 기준)에 대하여 썰물 때 1.97$\times$10 super(6) cm super(2)/sec, 밀물 때 1.69$\times$10 super(6) cm super(2)/sec였다. 썰물 때 확산계수가 큰 것은 교환능률이 컸음에 기인하여, 썰물 때 shear분산효과가 크다고 생각된다.