• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.632-635
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• 2003

원자력 발전소에서 배출되고 있는 방사성 폐기물의 운반 및 처분과 관련하여 규제가 예상되는 대상 핵종을 선정하고, 특히 방사능 계측기로 직접 측정이 불가능한 드럼 내 방출핵종에${\alpha}{\cdot}{\beta}$ 대한 농도 예측과 검증방법에 관한 연구가 진행되고 있다. 본 연구에서는 $\beta$방출 핵종이면서 반감기가 매우 긴 $^129I(t_{1/2}=1.57{\times}10^7)$의 정량을 위하여 모의 폐기물 중에 함유되어 있는 요오드의 분리 및 회수율을 측정하였다. 모의 폐기물중 가용성 및 난용성 시료의 전처리 방법으로 혼합산 분해법과 알칼리 용융방법을 각각 이용하였으며 두 방법에 대한 요오드의 회수율을 비교하였다. 요오드의 측정방법으로 이온 크로마토그라피를 이용하였으며 매질의 음이온성분에 의한 영향은 없었다. 두 방법의 전체 공정에서 혼합산분해에 의한 요오드의 회수율은 76.7 (RSD 1.7%)이고 알칼리용융에 의한 방법에서 모직물의 경우에는 74.3(RSD 2.2%)이고 Resin의 경우 56.5(5.6%)로 각각 나타났다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.488-491
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• 1997

The PMGS(Plant Model Generating System) was developed based on modular modeling method and fluid network calculation concept. Fluid network calculation is used as a method of real-time computation of fluid network, and the module which has a topology with node and branch is defined to take advantages of modular modeling. Also, the database which have a shared memory as an instance is designed to manage simulation data in real-time. The applicability of the PMGS was examined implementing the HRSG(Heat Recovery Steam Generator) control logic on DCS.

• 환경위생공학
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• 제12권3호
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• pp.81-86
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• 1997

In case of Industrial Wastewater, It was various pollutions, high concentration and different physical, chemical properties each other in accordance with classification of wastewater. Therefore, after inquiring into the influence on the membrane of the dissolved pollutants, we should select the membrane of best efficient quality. As results of experiments on pilot plant test, optimum operating pressure for fouling removal was 34BAR, when continues operating was 34 BAR, recovery rate was 75% and permeate water flux was $32.9{\;}{\ell}/hr{\cdot}m^{2}$.

• 한국막학회:학술대회논문집
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• 한국막학회 1996년도 추계 총회 및 학술발표회
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• pp.22-33
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• 1996

With the experience of the 1994 drought, and the shortage of water resources in Japan, it has been re-informed upon us ensure and maintain the stability of water resources. Accordingly, with each plant, a serious appraisal has begun looking at the re-use of waste water. Membrane technology is an important process for waste water recovery. Effluent kom waste water facilities changes the quality of water significantly. The conventional pre-treatment of RO is hard to supply good quality feed water to RO in the waste water recovery system. The microfiltration system as a pre-treatment of RO in the paper overcomes the fouling with the air backwash and is operated in direct flow mode at a low pressure producing a high flux. The paper will focus the waste water recovery using membrane technology and many examples will be given.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.674-680
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• 2023

The brine and seawater are important and largely untapped sources of critical trace metals and elements. The coupling of selective recovery of trace metals from seawater/brine with desalination plants gives an added advantage of energy credits to desalination plants and as well as reduce the cost of desalinated water. In this paper, status review on recovery of important trace metals and other alkali metals from seawater is presented. The potential of Indian desalination plants for recovery of trace metals, based on recovery ratio of 0.35 is also highlighted. Studies carried out by the process based on adsorption using Radiation Induced Grafted (RIG) polymeric adsorbents and then fractional elutions are presented. The fouling factors due to bio fouling and dirt fouling have been estimated for various locations of interest through field trails. The pay loader in the form of compact Contactor Assembly with minimum pressure drop, for loading specially designed radiation grafted sorbent in leaflet form has been briefed, as required for plant scale facility. The typical conceptual process design details of farm assembly of project CRUDE are described.

• 한국작물학회지
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• 제50권1호
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• pp.16-21
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• 2005

This study was conducted to establish the elaborate nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy. The nitrogen uptake by rice plants was insignificant until 25 days after seeding, and increased gradually thereafter. During this early growth stage, rice plants absorbed only the $4\%$ of basal applied N, while the $45\%$ of N fertilizer remained in the paddy soil. The absorption of basal N by rice plants was almost completed at 46 days after application. Nitrogen top-dressed at 5-leaf stage was well matched to crop nutrient demand, so it could be absorbed so actively in 8days after application. As a result, we could cut down the amount of N fertilizer to $36\%$ of the basal N level without significant difference in yield. Plant recoveries of fertilizer $^{15}N$ applied with different application timings were $7.8\%$ for basal, $9.4\%$ for 5-leaf stage, $17.1\%$ for tillering stage, and $23.4\%$ for panicle initiation stage, respectively. When urea was applied with nitrogen fertilization practice based on basal incorporation (BN), plant recovery of $^{15}N$ at harvest was $31.0\%$, which was originated from $13.7\%$ for grain, and $21.3\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. Plant recovery of fertilizer $^{15}N$ applied with nitrogen fertilization practice based on topdressing at 5-leaf stage (TN), where N rate was reduced by $18\%$ compared with BN, was $35.1\%$ (grain $15.6\%$), and $19.9\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. TN showed a higher $^{15}N$ recovery than BN because it was to apply N fertilizer at a time to well meet the demand of rice plant direct-seeded on flooded paddy. We concluded that TN would be the nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy.

• 대한환경공학회지
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• 제39권8호
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• pp.462-469
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• 2017

최근 부영양화 문제, 인광석 자원이 부족해지고 있는 국제적 상황, 하수처리장 관로 스케일 문제 등에 대응하기 위하여, Struvite 결정화 공정을 하수처리장 슬러지처리 계통의 고농도 인 제거/회수에 적용하려는 시도를 하고 있다. 본 연구는 실제 국내 하수처리장 슬러지처리 계통에 대한 Struvite 결정화 공정 적용 가능성을 평가를 목표하여, 첫째, 운영자료 및 현장측정자료 분석을 통하여 실제 하수처리장 슬러지처리 계통의 인 농도 및 물질수지를 분석하였고, 둘째, 평형화학 계산 프로그램을 활용하여 Struvite 결정화 반응 포텐셜, 이에 따른 최적 $Mg^{2+}$ 주입량, pH 등에 관해 연구하였고, 셋째, 실험실규모 배치실험을 통해 실제 Struvite 결정화 반응 동역학에 대해 연구하였다. 슬러지처리 계통에서의 인 농도 및 물질수지를 분석하였을 때, Struvite 결정화 공정은 소화슬러지 및 탈리여액에 적용함이 바람직한 것으로 파악되었다. 평형화학 계산결과, 안정적인 공정 운영을 위해서는 pH 8 이상, $Mg^{2+}$ 주입량은 몰비 기준 이론 요구량의 1.2배 이상을 첨가해야 하는 것으로 파악하였다. 그리고, Struvite 결정화 반응 동역학은 1차 반응속도식을 따르고, Struvite 결정화 반응이 평형상태에 도달한 경우, 모든 pH 조건에서 인산염인 제거율이 80% 이상으로 우수하게 나타났다. Struvite 결정화 반응 시 NaOH 첨가 없이 폭기만으로 $CO_2$ 탈기를 일으켜 반응 종결 후 pH 8.7 이상까지 상승했으며, $Mg^{2+}$ 주입원의 경우 간수 등 저가 대체물질을 활용할 수 있으므로, 약품비에 의한 운영비 증대 없이 Struvite 결정화 공정을 적용할 수 있으리라 판단된다.

• Journal of Plant Biology
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• 제33권2호
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• pp.135-140
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• 1990

The membrane potential in the subepidermal cells of Lemna gibba G3 fronds was measured in the dark with glass capillary microelectrodes. At pH 7, the membrane potential, approximately-215 mV, could be depolarized to -82∼-88 mV by 0.1 mM dicyclohexylcarbodiimide (DCCD) or by KCN at 0.3 mM or higher concentrations. When the pH of the medium was altered the potential showed reversible changes, while it revealed no response to the external pH changes when energy transduction across the membrane was being blocked by 0.1 mM DCCD. The results support an assumption that the active component of the membrane potential of Lemna subepidermal cells is generated by electrogenic H+ -pump. By the addition of 0.10∼5.00 mM salicylic acid(SA) to the bathing medium the membrane potential was depolarized to a great extent, and the removal of SA from the medium repolarized the potential showing almost complete recovery, 92.3∼97.6% to the initial levels. Although the potential was greatly depolarized by 5.0% or higher concentrations of dimethylsulfoxide (DMSO), the recovery rate by DMSO removal was decreased as the pretreatment concentration had increased. Twenty percent DMSO pretreatment limited the recovery at only 47.1%. The presence of SA in the bathing medium could reversibly increase the permeability of the plasmalemma. DMSO at its concentration of 5.0% or higher increased the permeability of the membrane by irrevesibly impairing the membrane component involved in the membrane permeability.

• 한국가스학회지
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• 제15권1호
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• pp.40-45
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• 2011

공정운전 중 운전자의 실수나 장치의 고장 등으로 형성되는 과압을 방지하기 위해 blowdown system을 통해 가스를 방출시켜 과압을 해소한다. 방출된 가스는 대부분 탄화수소 혼합물로서 가연성과 독성을 가지고 있으므로 플레어스택에서 연소시킨 후, 공기 중으로 배출시킨다. 그러나 화학공장의 규모가 증가하고 복잡해지면서 폐가스의 양이 증가하여 안전상의 이유로 플레어스택의 높이를 높이거나 추가적인 플레어시스템을 설치하여야 하는 문제가 발생하였다. 이 논문에서는 이러한 문제를 해결하기 위해 버려지는 폐가스를 회수하여 연료로 사용하는 Flare Gas Recovery System을 도입한 해결방안을 제시하고자 하였다.

• Korean Chemical Engineering Research
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• 제54권2호
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• pp.229-233
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• 2016

본 연구에서는 식물세포배양액으로부터 파클리탁셀을 효율적으로 회수하기 위하여 초음파를 이용한 액-액 추출 공정을 개발하였다. 액-액 추출을 위한 최적의 초음파 파워와 조업 시간은 주어진 하층(메틸렌 클로라이드 층)/상층(메탄올 농축액 층) 비(25%, v/v)에서 각각 250W와 15 min임을 알 수 있었다. 최적 조건 하에서 초음파를 이용한 액-액 추출 공정의 경우 단 1 회 추출로 대부분의 파클리탁셀을 하층(메틸렌 클로라이드 층)으로부터 회수(~92%) 가능하였다. 또한 무기염 첨가에 의한 초음파 상승효과로 인하여 액-액 추출을 위하여 적절한 무기염 농도와 초음파 파워가 요구됨을 알 수 있었다.