• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.02a
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• pp.182-190
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• 2004

An unique extraction chromatographic column (TOA: Tri-n-octylamine on Teflon powder) with a two-stage sample loading was prepared to separate Np and Pu from the environmental matrix. Np and Pu were efficiently retained in 4 M $HNO_3$ medium on the column and easily eluted with 0.02 M oxalic acid in 0.16 M HNO$_3$at $95^{\circ}C$. The separated solutions were free from most of the matrix elements and were aspirated into the ICP-MS directly. The decontamination factor for 238U is more than 104. The instrumental detection limit for 237Np was 0.46 pg mL-l ($1.2{\times}10_{-5}$Bq mL-l), and for 239Pu was 0.48 pg mL-l ($1.1{\times}10_{-3}$ Bq mL-l). The feasibility for the determination of both elements was proved by analysing IAEA-135 reference samples, the measured values agreed with the recommended reference value.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.02a
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• pp.106-113
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• 2004

A major problem of nuclear energy is the production of radioactive wastes. Needs for more environmentally favorable method to decontaminate radioactive contaminants make the use of liquid/Supercritical $CO_2$ as a solvent medium. In removing radioactive metallic contaminants under $CO_2$ solvent, two methods - use of chelating ligands and that of water in $CO_2$ emulsion - are possible. In the chelating ligand method, a combination of ligands that can make synergistic effects seems important. We discuss about the properties of microemulsion formed by F-AOT. By adding acid in water core, decontamination of metallic parts, soils were possible.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.11a
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• pp.133-134
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• 2009

조사 핵연료 및 구조재료의 핫셀시험을 위한 조사재시험시설은 고방사능물질의 시험 및 취급과정에서 발생한 각종 방사성 물질에 오염된 공기를 정회하기 위한 특수 공기조화설비를 운영하고 있다. 시설의 배기 계통은 핫셀 계통 및 핫셀 이외의 계통으로 니눠지고 있다. 그 중 핫셀 구역 이외의 공기는 1차적으로 프리필터와 HEPA 필터로 구성된 AFU(Air Filtering Unit)로 정화하여 외부에 방출하는 MUP(Medium Under Pressure) 시스템을 채용하고 있다. 외부에 방출하는 배기의 오염을 최소화하기 위하여 설치된 AFU에 대한 풍량 측정 및 HEPA필터의 성능시험을 실시하였으며, 그 결과에 대하여 고찰하였다.

• 연구논문집
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• s.32
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• pp.5-13
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• 2002

This paper deals with the result of an analysis on the effect of the power generation by municipal solid waste(MSW)-refuse derived fuel(RDF) and the introduction of tipping fee sharing between RDF manufacturing and power generation project. As a model case for the MSW generated at small and medium cities in our country, an analysis of the RDF power generation and Tipping fee sharing shows that 1) MSW amount of 7,800* $10^3 $t/y could produce 1,950*$10^3$t/y of RDF 2) Electric power generated by MSW-RDF could supply 290,000 households/year and 98,548 C-t/y of $CO_2$ could be reduced. 3) Tipping Fee should be shared by the considering of the contents of project of both side between RDF Production and power generation.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2006.09a
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• pp.3-12
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• 2006

The main feature of these total technologies is that we can constitute the optimum treatment scheme fitting to the property of wastes, amount of wastes and energy requirement. For high moisture content wastes or biomass resources, high pressure steam process (MMCS) for crush, dry and deodorize wastes to produce high quality fertilizer of fuel is most appropriate. For dry or semi-dry solid wastes, the STAR-MEET system can be applied to produce low-BTU gases for power generation using duel fueled diesel engines of Stirling engines, and the REPRES and HyPR-MEET systems can be applied to produce hydrogen rich medium-BTU gas. For waste plastics and oils, liquefaction technology is best fit to produce light oil or kerosene equivalent fuel oils. These total technologies are completely different from the existent waste treatment technologies based on land-filling or incineration, and are expected to disseminate all over the world in the near future.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.4
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• pp.457-464
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• 2020

In this study, extraction of uranium(VI) from an aqueous nitric acid solution was investigated using tri-n-butyl phosphate (TBP) as an extractant in an ionic liquid, 1-alkyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide ([Cnmim][Tf2N]). The distribution ratio of U(VI) in 1.1 M TBP/[Cnmim][Tf2N] was significantly high when the concentration of nitric acid was low. The value of the distribution ratio decreased as the concentration of the nitric acid increased at lower acidities, and then increased with a nitric acid concentration of up to 8 M. This can be attributed to the different extraction mechanisms of U(VI) based on nitric acid concentrations. Thus, a cation exchange at low acidity levels and an ion-pair extraction at high acidity levels were suggested as the extraction mechanism of U(VI) in the TBP/[Cnmim][Tf2N] system.

• Membrane and Water Treatment
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• v.9 no.5
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• pp.327-334
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• 2018

The nano/micro composites with highly porous surface area have attracted of great interest, particularly the synthesis of porous and thin film sheets of high performance. In this paper, an easy method of cost-effective synthesis of thin film ceramic fiber membranes based on Hydroxyapatite, and activated carbon by turned into studied to be applied within the service-facilitated the transport of radioactive waste such as $^{90}Sr$, $^{137}Cs$ and $^{60}Co$) as activated product of radioisotopes from ETRR-2 research reactor and dissolved in 3M $HNO_3$, across a thin flat-sheet supported liquid membrane (TFSSLM). Radionuclides are transported from alkaline pH values. The presence of sodium salts in the aqueous media improves in $HNO_3$, the lowering of permeability because the initial $HNO_3$ concentration is improved. The study some parameters on the thin sheet ceramic supported liquid membrane. EDTA as stripping phase concentration, time of extraction and temperature were studied. The study of maximum permeability of radioisotopes for all parameters. The pertraction of a radioactive waste solution from nitrate medium were examined at the optimized conditions. Under the optimum experimental 98.6-99.9% of $^{90}Sr$, 79.65-80.3% of $^{137}Cs$ and $^{60}Co$ 45.5-55.5% in 90-110 min with were extracted in 10-30 min, respectively. The process of diffusion in liquid membranes is governed by the chemical diffusion process.

• Journal of Microbiology and Biotechnology
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• v.18 no.8
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• pp.1408-1415
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• 2008

To produce polyhydroxyalkanoate (PHA) from inexpensive substrates by bacteria, vegetable-oil-degrading bacteria were isolated from a rice field using enrichment cultivation. The isolated Pseudomonas sp. strain DR2 showed clear orange or red spots of accumulated PHA granules when grown on phosphate and nitrogen limited medium containing vegetable oil as the sole carbon source and stained with Nile blue A. Up to 37.34% (w/w) of intracellular PHA was produced from corn oil, which consisted of three major 3-hydroxyalkanoates; octanoic (C8:0, 37.75% of the total 3-hydroxyalkanoate content of PHA), decanoic (C10:0, 36.74%), and dodecanoic (C12:0, 11.36%). Pseudomonas sp. strain DR2 accumulated up to 23.52% (w/w) of $PHA_{MCL}$ from waste vegetable oil. The proportion of 3-hydroxyalkanoate of the waste vegetable-oil-derived PHA [hexanoic (5.86%), octanoic (45.67%), decanoic (34.88%), tetradecanoic (8.35%), and hexadecanoic (5.24%)] showed a composition ratio different from that of the corn-oil-derived PHA. Strain DR2 used three major fatty acids in the same ratio, and linoleic acid was the major source of PHA production. Interestingly, the production of PHA in Pseudomonas sp. strain DR2 could not occur in either acetate- or butyrate-amended media. Pseudomonas sp. strain DR2 accumulated a greater amount of PHA than other well-studied strains (Chromobacterium violaceum and Ralstonia eutropha H16) when grown on vegetable oil. The data showed that Pseudomonas sp. strain DR2 was capable of producing PHA from waste vegetable oil.

• The Korean Journal of Mycology
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• v.20 no.4
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• pp.354-359
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• 1992

The effect of the addition of various vegetable oils on the mycelial growth was studied. Most vegetable oils were proved to be stimulative for the mycelial growth, and the best mycelial growth (12 mg/ml) was obtained with the addition of cotton seed oil. Several agricultural wastes i.e., rice straw, peanut hull, sawdust, rice hull, cocoa hull, coffee waste and beer waste were empolyed as substrates for sporophore production of p. sajor-caju. The biological efficiency(BE) for sporophore productions of rice straw and peanut hull were 36.4% and 32.6%, respectively. The highest yield of sporophore was obtained from the mixture of rice straw (50%) and beer waste (50%)(BE 109.6%) followed by peanut hull (50%) and beer waste (50%)(BE; 74.5%).

• Journal of Animal Environmental Science
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• v.6 no.3
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• pp.201-209
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• 2000

Optimal conditions to utilize egg type male chicks from hatchery for cultivating yeast(Saccharomyces cerevisiae) and the effects of the yeast culture on growth of broiler chicks were investigated. The protein concentration of the spent cockerel extracts was the highest when extracted for 72 hours. Optimal water volume added to the spent cockerel chicks for the extraction was 1.5 times to the cockerel chicks weight (v/w ratio). Lipid in the extracts from the spent cockerel chicks did not affect on the yeast growth. The number of yeast cultured in the SCELP2 medium containing spent cockerel extracts and 4 % sugarcane molasses was higher by 26 % than that in the YEPD medium containing 1 % yeast extract, 2 % bacto pepton and 2 % glucose. Also the number of yeast cultured in the SBYW2 medium containing SCEP2 medium containing SCELP2 and 4 % brewer's yeast waste was increased by 8 %, compared to that in the SCELP2 medium. Body weight gain of chicks fed 4 % yeast culture supplementations cultivated in the SBYW2 medium was increased at 5 weeks by 9 %, relative to no supplementation(P<0.05). The results from this study suggest that the spent cockerel chicks can be utilized as nitrogen sources to produce yeast culture for animal feed.