• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.2
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• pp.5-10
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• 2018

This study was evaluated the characteristics of organic materials in the water source and the removal characteristics of organic materials by ultrafiltration including mixing and coagulation process. As a results of the study, it was found that the total organic carbon in the water source was mostly caused by the dissolved organic materials. As the specific ultraviolet absorbance value of the raw water was low, we found the soluble organic material has a high hydrophilic and low molecular material composition ratio. As a result of ultrafiltration experiment including mixing and coagulation process, the average removal rate of total organic carbon, dissolved organic carbon and ultraviolet absorbance at 254 were 37.9%, 30.3%, and 28.2%, respectively.

• Economic and Environmental Geology
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• v.43 no.1
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• pp.33-42
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• 2010

The purpose of this study was to understand the degree of natural radon removal efficiency of small-scale water supply systems. Six sites were selected for this study, and data on well characteristics (depth, pumping rate, water tank capacity, distance from well to tap water) were obtained. Water samples both from raw water and three tap waters at each site were collected and analyzed for radon concentration. Average radon removal efficiency of the five sites (A-E) in Nov. 2006 was 26.0% while that of the same sites in Dec. 2006 was 45.6% indicating seasonal difference in natural radon removal efficiency. Meanwhile short-term (April 23, April 30, May 8, 2007) radon removal efficiency from the site F was 44.1-49.0%, implying only a little difference in natural radon removal efficiency. The degree of radon removal at tap water was influenced mainly by pumping rate rather than distance from the well and water tank capacity.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1031-1037
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• 2006

The main purposes of this study were to compare the characteristics of fractionated natural organic matters(NOM) from Han River water and Wangsuk(W) stream water, and to investigate the relationships between NOM and the formation of disinfection by products(DBPs). Three types of resin such as XAD-4, XAD-7HP and IRC-50 were used to isolate the water samples into three organic fractions. The DOC concentrations of raw waters were relatively low($1.5{\sim}3.3$ mg/L) at all seasons. The hydrophilic was the major constituent, contributing $44{\sim}63%$ of the total NOM and hydrophobic $21{\sim}33%$, transphilic $16{\sim}31%$, respectively. The formation of trihalomethans(THMs) was highly influenced by particulated NOM especially in the rainy season, whereas haloaceticacid forming potentials(HAAFPs) depended more on the hydrophilic fraction of dissolved NOM which is known to be difficult to be removed through conventional processes. The NOM of W stream was characterized as 15% hydrophobic, 9% transphilic, and 76% hydrophilic. In the fractionation of NOM using resins, $20{\sim}40%$ of the NOM in W tributary water could not be clearly isolated, whereas, 85% of the NOM in the raw water was recovered. Although the DOC concentration of tributary water was higher than the raw waters from the Han River, the DBPFPs was approximately 40% of the raw waters. In DBPFPs aspect, W stream has less effect than Han River water itself. Bromide in tributary waters discharged from waste water treatment plants has been found to shift the distribution of THMs and HANs to the more brominated DBPs.

• 월간 기계설비
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• s.259
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• pp.58-60
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• 2012

국토해양부는 공공공사 건설근로자에 대한 임금체불을 방지하기 위해 '건설근로자 노무비 구분관리 및 지급확인 지침'을 마련하고 지난 1월 1일부터 시행에 들어갔다. 이에 따라 공공건설공사 현장의 원수급인은 매월 하수급인이 고용한 근로자를 포함한 모든 건설근로자의 실제 근무내역을 작성해 발주자에게 노무비를 청구해야 한다. 또한 발주자는 원 하수급인이 건설근로자에게 실제 지급한 임금 지급내역을 확인한 뒤 같은 달 청구된 노무비를 지급하고, 이어 원수급인은 하수급인의 노무비 전용통장으로 이를 지급해야 한다. 아울러 발주자와 원수급인은 '노무비 알리미 서비스'를 통해 노무비 지급 사실을 해당 건설근로자에게 문자 메시지로 통보함으로써 임금지급 절차가 진행되고 있음을 사전에 근로자들에게 알려줘야 한다.

• Water for future
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• v.23 no.3
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• pp.363-371
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• 1990

Foundational experiments are conducted to examine the applicability of redox control in brak-point chlorination of ammonia on drinking water purification. Through the research, the behauial affects by ph and temperature to a chloromine forming reactions are evaluated. The possibility of redox control in breakpoint chlorination is recoguized by drawing up the titration curve in terms of redox potential and $C{\ell}_2$/N ratios.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.04b
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• pp.40-42
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• 1997

수처리 공정의 목적은 원수 중에 포함된 콜로이드, 미립자 등의 현탁물질, 이온과 유기물 등의 용해성 물질의 제거로, 이러한 목적을 위해서 수처리공정에 막분리 기술을 이용하는데 관심이 높아지고 있고, 이미 일부에서는 실용화되었다. 분리막에는 분리막의 기공의 크기에 따라 역삼투막, 한외여과막, 정밀여과막이 있으며, 대상 폐수 및 처리수의 재활용 여부에 따라 선정하여 사용한다. 본 연구에서는 폴리설폰 재질의 중공사하여 한외여과막을 사용하여 하천수를 처리하여 투과수와 원수의 수질을 비교함으로써, 분리막 기술에 의한 하천수처리의 타당성 및 처리 효율을 고찰해 보고자 하였다. 대상 원수로 최근 생활하수의 유입으로 수질이 악화되고 있는 소양강의 한 지류인 공지천의 물을 사용하였다.

• Korean Security Journal
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• no.41
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• pp.67-96
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• 2014

Today each country in the world goes beyond the narrow concept of national security that was limited to national defense and ideology and are entering multi-dimensional global system mainly based on economic profits. Nevertheless, conflicts between nations due to religious and ideological reasons have brought unprecedentedly intense disputes Security services for head of states have been an important national mission in every era and society. However, they are becoming a main target for assassination and attacks by terrorists. Attacks on the head of state and other VIPs can cause aftermath ranging from war to conflict situation, political crisis, and economic loss. Therefore this study aims to draw insights by comparing protective security units of Korea, the U.S., and Japan which have different legal basis and sociocultural characteristics. Especially in South Korea, which faces difficult diplomatic stance due to the tension with North Korea and relationship with other countries such as the U.S., China, and Russia as well as polarization between classes, generations, regions, and ideologies, cohesion among members of society has weakened and hatred toward the head of state has been brought, which emphasizes the important of national security services. Therefore the study of protective security units and its operation by comparison between neighboring countries will be able to bring insights on the promotion of the security service.

• Membrane Journal
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• v.26 no.1
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• pp.70-75
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• 2016

The reuse of wastewater is being diffused to manage and develop the water resources. Generally, the treated wastewater is discharged to the river after being treated to meet the effluent quality standard or reused for diverse uses through the reprocessing. And recently, as the reuse of the treated wastewater is activated, the technologies to utilize for the high quality water resources such as industrial water by reusing the wastewater with Membrane Distillation (MD) are under development. In this study, the direct contact membrane distillation (DCMD) process has been applied to treat sewage discharge water for water reuse. The laboratory scale experiment was performed by using a hydrophobic PVDF membrane with the pore size of $0.22{\mu}m$. The influence of operating parameters, such as feed temperature, feed flow rate, feed concentration, on the permeate flux and rejection has been investigated. All filtration tests were conducted till the feed volume reached a concentration factor of 3.0. Thus, the operating period ranged between 19 hr and 49 hr depending on filtration performance. The results showed that above 92% of TN, TP, COD and TOC in the feed could be rejected regardless of an operating condition. The water flux was ranged from 13.8 to 20.3 LMH. The lowest flux was obtained at the operating condition with the feed temperature of $50^{\circ}C$ and feed flow velocity of 500 mL/min while the highest one was measured with $60^{\circ}C$ and 900 mL/min. When the concentration factor reached 3.0, water flux declined by approximately ranged from 14.5% to 33.3%. But the fouling in MD is almost fully reversible, with more than 90% recovery of permeate water flux following a DI water rinse without the addition of chemical cleaning reagents.

• The monthly packaging world
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• s.43
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• pp.174-179
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• 1996

• Food Industry
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• s.13
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• pp.54-57
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• 1973