• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.83-86
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• 2001

This paper aims to make a feasibility study and to propose a master plan for the development of "integrated ocean energy utilization system", which utilizes various renewable ocean energies. Fossils energy, as the most important energy resources which are inevitable for the living and industrial development, becomes exhausted and its consumption creates serious environmental problem. It is important to utilize renewable ocean energy for a sustainable and environmentally friendly development. We survey the integrated utilization of ocean energy based on surveyed energy density distribution and propose concepts of integrated ocean energy utilization plant for both onshore and offshore system. The results of this study can support national effort for renewable energy development utilizing integrated ocean energy and refer as a guideline for the technical development of sustainable integrated ocean energy.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2008년도 추계학술발표회
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• pp.59-66
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• 2008

• 자원리싸이클링
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• 제31권2호
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• pp.56-62
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• 2022

본 연구에서는 탄산나트륨(Na₂CO₃)을 사용하여 염배소한 함바나듐 티탄철광(VTM)으로부터 바나듐의 수침출 거동을 고찰하였다. 자력선별 된 정광과 Na₂CO₃를 질량비 4:1로 혼합한 후 1050 ℃, 3시간 조건에서 염배소하고 로드밀을 사용해 D₅₀=48.79 ㎛로 분쇄하여 연구에 사용하였으며 침출 온도와 광액 농도를 수침출 영향인자로 선정하였다. 연구 결과, 온도가 25, 55, 85 ℃로 증가할수록 바나듐의 침출율은 90.4, 88.2, 83.8%로 감소하였으며 광액 농도 10, 50, 100 w/v%에 따른 바나듐 침출율은 각각 90.4, 87.0, 87.0%로 변화가 크지 않았다. 이를 바탕으로 25 ℃, 100 w/v%, 300 rpm, 1시간의 조건에서 다단 침출을 수행한 결과, 총 4단 침출 후 최종 침출액의 바나듐 농도는 16.20 g/L로 분석되었다. 따라서 다단 침출을 통해 고농도 소듐바나데이트 용액의 제조가 가능하였다.

• 자원리싸이클링
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• 제33권3호
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• pp.48-56
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• 2024

본 연구에서는 하수슬러지 가스화 고형 잔류물(GSRs)의 순환자원 활용 가능성을 검토하기 위해 대상제품에 대한 물성평가 및 물리적 분리를 수행하였다. 먼저, 본 연구에 사용된 GSRs는 수도권매립지관리공사를 통해 공급되었으며, 일반적으로 GSRs는 수 mm 입자크기의 다공성 펠릿 형태이었다. 또한, 부분적으로 검은 부분은 미연소 및 가스화되지 않은 탄소로 확인되었으며, 평균 탄소 함량은 5%였다. 또한 실리카, 알루미나, 산화인의 성분이 전체 함량의 70% 이상이었다. 습식분쇄 생성물은 금속성분이 단체분리되어있음 확인하였다. 금속성분과 비금속성분의 물리적 분리가 필요하여 최종적으로 부유선별에 적합한 것으로 결정하였다. 이에, 상대적으로 많은 양의 비금속성분이 농축된 금속 성분을 분리하기 위해 양이온 및 음이온 계면활성제를 선택하여 분리 특성을 확인하고자 하였다. 결과적으로, 금속성분 분리보다 실리카, 알루미나, 인 등 비금속 성분의 농축이 더 용이할 것으로 기대된다. 따라서, 가스화 처리된 하수슬러지 잔재물의 물리적 처리에 가능함에 따라 분리산물에 대한 재활용 방안 제안에 따라 순환자원으로서 잠재성이 있을 것으로 판단된다.

• Journal of Microbiology and Biotechnology
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• 제23권4호
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• pp.437-443
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• 2013

The diversity of culturable non-actinobacterial (NA) bacteria associated with four species of South China Sea gorgonians was investigated using culture-dependent methods followed by analysis of the bacterial 16S rDNA sequence. A total of 76 bacterial isolates were recovered and identified, which belonged to 21 species of 7 genera, and Bacillus was the most diverse genus. Fifty-one percent of the 76 isolates displayed antibacterial activities, and most of them belonged to the Bacillus genus. From the culture broth of gorgonian-associated Bacillus methylotrophicus SCSGAB0092 isolated from gorgonian Melitodes squamata, 11 antimicrobial lipopeptides including seven surfactins and four iturins were obtained. These results imply that Bacillus strains associated with gorgonians play roles in coral defense mechanisms through producing antimicrobial substances. This study, for the first time, compares the diversity of culturable NA bacterial communities among four species of South China Sea gorgonians and investigates the secondary metabolites of gorgonian-associated B. methylotrophicus SCSGAB0092.

• Journal of Microbiology
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• 제43권5호
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• pp.417-423
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• 2005

In this study, the nematode-trapping fungus, Monacrosporium sphaeroides, was transformed with a plasmid harboring the hygromycin B phosphotransferase gene, via restriction enzyme-mediated integration (REMI). Frequencies of up to 94 transformants ${\mu}g^{-1}$ per linearized plasmid DNA were obtained by optimizing the PEG concentration, as well as the category and quantity of the added restriction enzyme. $90\%$ of the transformants were determined to be stable for drug resistance when 20 randomly selected transformants were tested. Southern analyses revealed that the transforming DNA was integrated into the M. sphaeroides genome either with or without rearrangement. Five mitotic stable mutant strains were obtained using this approach, all of which had been altered with regard to sporulation capacity and pathogenicity toward nematodes. Southern blot analyses of the five mutants revealed that foreign plasmid DNA had integrated into the genome. Three of the mutants, Tms2316, Tms3583 and Tms1536, exhibited integration at a single location, whereas the remaining two, Tms32 and Tms1913, manifested integration at double or multiple locations. Our results suggest that the transformation of M. sphaeroides via REMI will facilitate insertional mutagenesis, the functional analysis of a variety of genes, and the tagging or cloning of genes of interest.

• Korean Journal of Chemical Engineering
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• 제35권12호
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• pp.2336-2347
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• 2018

The azeotrope of methyl acetate methanol and water was isolated using extractive distillation with water as entrainer. The pressure-swing extractive distillation (PSED) process and vapor side-stream distillation column (VSDC) with the rectifier process were designed to separate the methyl acetate, methanol and water mixture. It was revealed that the VSDC with the rectifier process had a reduction in energy consumption than the PSED process. Four control schemes of the two process were investigated: Double temperature control scheme (CS1), $Q_R/F$ feedforward control of reboiler duty scheme for PESD (CS2), $Q_R/F$ feedback control scheme for VSDC (CS3), the feedback control scheme of sensitive plate temperature of side-drawing distillation column to dominate the compressor shaft speed (CS4). Feed flow and composition disturbance were used to evaluate the dynamic performance. As a result, CS4 is a preferable choice for separation of methyl acetate-methanol-water mixture. A control scheme combining the operating parameters of dynamic equipment with the control indicators of static equipment was proposed in this paper. It means using the sensitive plate temperature of side-drawing column to control the compressor shaft speed. This is a new control scheme for extractive distillation.

• 한국입자에어로졸학회지
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• 제13권1호
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• pp.33-40
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• 2017

Cobalt-iron oxides have emerged as alternative electrode materials for supercapacitors because they have advantages of low cost, natural abundance, and environmental friendliness. Graphene loaded with cobalt ferrite ($CoFe_2O_4$) nanoparticles can exhibit enhanced specific capacitance. In this study, we present three-dimensional (3D) crumpled graphene (CGR) decorated with $CoFe_2O_4$ nanoparticles. The $CoFe_2O_4$-graphene composites were synthesized from a colloidal mixture of GO, iron (III) chloride hexahydrate ($FeCl_3{\cdot}6H_2O$) and cobalt chloride hexahydrate ($CoCl_2{\cdot}6H_2O$) respectively, via one step aerosol spray pyrolysis. Size of $CoFe_2O_4$ nanoparticles was ranged from 5 nm to 10 nm when loaded onto 500 nm CGR. The electrochemical performance of the $CoFe_2O_4$-graphene composites was examined. The $CoFe_2O_4$-graphene composite electrode showed the specific capacitance of $253F\;g^{-1}$.

• 한국입자에어로졸학회지
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• 제15권4호
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• pp.183-190
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• 2019

Here, we introduce porous graphene balls (PGB) showing superior electrochemical properties as supercapacitor electrode materials. PGB was fabricated via activation of graphene oxides (GO) by H₂O₂ and aerosol spray drying in series. Effect of activation on the morphology, specific surface area, pore volume, and electrochemical properties were investigated. As-prepared PGB showed spherical morphology containing pores, which lead to the effective prevention of restacking in graphene sheets. It also exhibited a large surface area, unique porous structures, and high electrical conductivity. The electrochemical properties of the PGB as electrode materials of supercapacitor are investigated by using aqueous KOH under symmetric two-electrode system. The highest specific capacitance of PGB was 279 F/g at 0.1 A/g. In addition, the high rate capability (93.8% retention) and long-term cycling stability (92.2%) of the PGB were found due to the facilitated ion mobility between the porous graphene layers.

• 한국농공학회지
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• 제29권2호
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• pp.30-38
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• 1987

Because the development of Korea's water resources will reach its limit in the near future, preparations should now be begun to deal with problems that may come as a result. It will be too late to start preparations when the water resources have already reach their limitation and, as the preparations cannot be done in a day, it will take a long time to provide them. Now is the great turning point to accumulate our technical experiences and attain our plans gradually. The preparations against this are summarized as follows; 1)The transitory use of water should be turn into the recurrent use for the future. 2)A cooperative water control system of an area should be arranged. 3)Water saving, control of water demand, and the multiple use of water should be encouraged. To do this effectively, people should be informed of the value and rarity of water. 4)The development of freshwater reserviors at estuaries is closely related to the development of water utilization in the whole river basin. The development of water resources by the construction of freshwater reservoirs at the estuaries should be started, when the development of upstream water resources reaches their limitation. 5)The existing water utilization structures should be reorganized by water resources exchange planning, so the effective use of water in large areas be attained.