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        검색결과 40

        1.
        2023.11 구독 인증기관·개인회원 무료
        Spent nuclear fuels (SNFs) are stored in nuclear power plants for a certain period of time and then transported to an interim storage facility. After that, SNFs are finally repackaged in a disposal canister at an encapsulation plant for final disposal. Finland and Sweden have already completed the design of the spent nuclear fuel encapsulation plant. In particular, Finland has begun the construction of the encapsulation plant and is on the verge of completion. Korea Radioactive Waste Agency (KORAD) is conducting a conceptual design of a deep geological repository for SNFs. Conceptual design of the encapsulation plant is part of the research activity. It is highly required to draft an operation process of the encapsulation plant before an actual design activity. As part of the activity, Finnish design concept of the encapsulation plant and experience were thoroughly reviewed. Finally a preliminary concept of the operation process was proposed considering Korean unique situations such as the volume of SNFs estimated to be disposed of, types of transportation cask and other considerations.
        2.
        2023.11 구독 인증기관·개인회원 무료
        After the decision of the Wolsong unit 1 permanent shutdown (2019), spent fuel stored in the spent fuel bay (hereafter, SFB) should be transported to a dry storage facility (MACSTOR or Canister) in order to decommission Wolsong unit 1. Accordingly, KHNP has established a shipment schedule for damaged fuel of Wolsong Unit 1 and is trying to complete the shipment according to the schedule. Wolsong is equipped with transportation casks and dry storage facilities, but baskets need to be manufactured separately. In addition, license approval is required for baskets, transport cask, and dry storage facilities for legal grounds to contain, transport, and store damaged fuels. In this paper, the initial model, upgrade model, and automation model of encapsulation equipment planned to be introduced in Canada to handle PHWR’s damaged fuel were compared, and the optimal model was selected in consideration of KHNP’s planned spent fuel shipment schedule. The PHWR’s damaged fuel encapsulation system is a system developed the PHWR’s damaged spent fuel to be handled in the same way as the existing PHWR when storing it in the dry storage facility and loading a basket for capsulation into transport cask. At the Gentilly-2 nuclear power plant in Canada, a manually operated encapsulation system was used due to the low quantity of damaged fuel, which can be encapsulated two bundles a day, and this model is an initial model. In the case of Wolsong Unit 1, it has about 300 damaged fuels, so it takes about nine months to work when using the initial model. The upgrade model developed to improve work efficiency and reliability has increased work efficiency through some automation, but it would take about eight months to process the damaged spent fuels of Wolsong Unit 1, and this model has not yet been manufactured and applied. Lastly, the automation model changed the work location outside the SFB and automated drainage/drying operations. It is easy to maintain and replace consumables because the work is carried out by lifting the damaged fuel to a shuttle outside the SFB surrounded by a shielding chimney. Considering the reduction of drainage/drying time, it is possible to save about four times as much time as the initial model. That is, if the automation model is used, it is judged that the supply of Wolsong Unit 1 can be processed in about two months. However, in terms of license, initial model and upgrade model are expected to be easier and the period is expected to be shortened. However, if licensing is carried out as soon as equipment design is completed, it is believed that the period can be shortened by parallel equipment manufacturing and licensing. It is judged that the best way to comply with the target schedule is to select an automation model with excellent work performance, develop equipment, and proceed with licensing at the same time. Accordingly, KHNP is in the process of designing equipment with the aim of using the automation model to take out damaged fuel for Wolsong Unit 1.
        4.
        2021.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this work, narrow-band green-emitting CsPbBr3 particles are embedded in commercialized glass composites by a facile dry process. By optimizing the method through sintering in glass frit (GF) composites including CsBr and PbBr2, used as precursors, the encapsulation of CsPbBr3 particles made them waterproof with green fluorescence. To improve the fluorescent properties by reducing aggregation of CsPbBr3, fumed silica (FS) is additionally used to help particles avoid bulking up in the glass matrix. The CsPbBr3 perovskite/glass composites are characterized using scanning electron microscopy (SEM) images and energy-dispersive X-ray spectroscopy (EDS) maps, which support the existence of CsPbBr3 particles in the glass matrix. The photoluminescence (PL) properties demonstrate that the emission spectrum peak, full width at half maximum (FWHM), and photoluminescence quantum yield (PLQY) values are 519 nm, 17 nm, and 17.7 %. We also confirm the water-resistant properties. To enhance water/moisture stability, the composite sample is put directly into water, with its PLQY monitored periodically under UV light.
        4,000원
        8.
        2018.04 구독 인증기관·개인회원 무료
        Probiotics are defined as advantageous microorganisms to human when they are ingested. However, without any protection, the viability of microbes and their adhesive ability to surface of colon decreases through acidic condition such as stomach and intestines. Therefore, many studies have been conducted to figure out to enhance not only the viability of probiotics, but also its adhesion for increasing effect of probiotics. In this study, extrusion method was conducted to encapsulate Enterococcus faecium. E. faecium-alginate solution was injected to CaCl2 solution with regular side air injection. To prevent coagulation of beads, stirring was conducted in CaCl2 solution and encapsulated alginate-Ca2+ microspheres were produced. For optimal encapsulation condition, air pressure was 100 mbar, flow rate of E. faecium solution was 0.02 ml/h and stirring rate was 200 rpm. For mucoadhesive ability, Monolayer of HT-29 cells used as a colon cell and encapsulated cells were inoculated and incubated in 37℃, 5% CO2/95% air atmosphere for 1 h. Encapsulation efficiency of the encapsulation method used in this study was 98.2%. For mucoadhesive test, the concentration of inoculated E. faecium was 9.9×108 CFU/ml and the concentration of adhered E. faecium was 1.6×106 CFU/ml. In conclusion, encapsulation efficiency of extrusion method was high enough to be accepted for this study, however, alginate-Ca2+ microspheres revealed lower adhesive ability compared to expectation. Therefore, it needs further studies to increase adhesive ability with other polymers.
        9.
        2017.11 구독 인증기관·개인회원 무료
        Starch is an abundant, renewable, and low cost material that has been extensively studied for its role in crystallization. Herein, we developed a facile and green approach to produce the starch-based microparticles (SMPs) that could encapsulate curcumin during the self-association of short glucan chain obtained from waxy maize starch. Scanning electron microscopy (SEM) analysis indicated that the diameters of curcumin-loaded SMPs were ranged from 1.5 μm to 3 μm. The characteristics of the curcumin-loaded SMPs were evaluated via Raman spectroscopy, confocal microscopy, UV spectrophotometer, and X-ray diffraction (XRD). The results showed that the suspended curcumin was encapsulated in SMPs in amorphous form with a encapsulating efficiency of about 96.36%. Photostability test confirmed that curcumin that is loaded inside SMPs was effectively protected against the photodegradation. Curcumin-loaded SMPs can be used not only in food industry for extending the shelf life of curcumin, but also in pharmaceutical industry to design effective carrier for oral delivery.
        10.
        2017.11 구독 인증기관·개인회원 무료
        Vitamin A is essential for growth and differentiation of a number of cells and tissues, as result the precursor, a carotenoid β-carotene remains their essential source of vitamin A. However, the major problem this carotenoid face, is its susceptible to photodegradation and chemical oxidation, those properties make it difficult to use as an ingredient as functional food product and reduce its bioavailability. This study presents a novel approach to prepare a one-step inclusion complex using amylose microparticles as host molecule using amylosucrase from Deinococcus geothermalis (DGAS) and β-carotene nanoparticles, which were added into the DGAS enzyme reaction solution to entrap them during the synthesis of amylose chains. HRFE-SEM showing a spherical shape and average diameter of 4-8 μm; XRD and DSC showed an amorphous structure as well as less energy required to start the gelatinization process, due to the complexation of amylose chains with the β-carotene nano dispersion. Last but not least Raman spectroscopy was performed in order to confirmed the complex formation between β-carotene and amylose microparticles, showing the characteristic peaks of both compound. The stability test in this study showed the high stability of the complexed microparticles against environmental stresses such as, photodegradation and chemical oxidation. We expect this study contributes to the development of functional food materials to enhance the stability and bioavailability of active compounds.
        12.
        2014.06 구독 인증기관 무료, 개인회원 유료
        본 실험은 국화의 바이로이드 제거에 이용되는 초저온처리 시 국화 품종 'White ND'을 적합한 처리조건을 확립하기 위해 초저온처리의 단계별 요인을 실험하였다. 그 결과 생장점의 크기는 1 mm(엽원기 2~3매 포함)에서 높은 생존율과 신초 재생율을 나타내었고, vitirification 처리시 PVS3가 효과적이었으며, 처리 시간은 60분 처리 하였을 때 높은 생존율 및 정 상 신초 재생율을 보였다. 또한 vitrification을 위한 전처리 조건은 sucrose 농도를 88 mM 24시간, sucrose 0.3 M 16시간, sucrose 0.5 M 6시간, sucrose 0.7 M 3시간으로 처리하는 것이 초저온 처리 후 생존율 및 신초 재생율을 높이는데 효과적이었으며, 재생된 정상 식물체는 모본과 비교하여 ploidy level이 동일한 것으로 보아 식물체의 유전적 변이가 일어나지 않았다.
        4,000원
        13.
        2013.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 아질산염 대체제로서 녹차, 세이지, 파프리카 올레오레진 추출물을 미세캡슐 화하여 돈육 패티 제조과정에서 첨가 시 4oC의 저장과정에서 색도, 총 플라보노이드 함량, DPPH radical 소거활성, TBARS, 총균수 등의 변화를 비교 분석하였다. 색도에서는 미세캡슐화한 처리구 2가 비 캡슐화의 처리구 1나 아질산염첨가 대조구보다 저장기간 내내 높은 a 값을 보였다. 총 플라보노이드함량에 있어서 저장초기 대조구와 처리구간에 유사한 값을보였으나 저장 7일후에는 저장초기대비 대조구는 약 52%의 감소가 나타난 반면 처리구 1과 처리구 2에서는 각각47과 43%가 감소하였다. DPPH radical 소거활성은 저장초기의 대조구가 8.68%로서 가장 낮았으며 처리구 1과 처리구 2는 각각 18.15와 23.27%로 높게 나타났다. TBARS값에서는 대조구, 처리구1 및 처리구 2는 각각 0.54, 0.36및 0.33mg/kg으로 나타나 아질산염을 첨가한 대조구가 천연첨가물의 처리군에 비하여 높은 값을 보였다. 저장과정에서도 저장 7일 후 대조구는 약 61%의 증가가 있었던반면 처리구 2에서는 약 30%의 증가에 그쳤다. 총균수에서는 저장초기 대조구와 처리군 간의 차이가 없었으며2.98-3.38log CFU/g 수준이었고 저장 중 급격한 증식이없었다. 저장 7일 후에도 3.32-3.64log CFU/g 수준으로유의성차이를 보이지 않았다.
        4,000원
        14.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        hydroxycinnamic acid인 ferulic acid와 caffeic acid는 강력한 식물성 항산화제 이다. DPPH 수용액에서 이들의 자유라디칼 소거능과 높은 온도, 금속 이온과 같은 산화촉진 요인에 대한 화학적 안정성 등을 살펴보았다. 아스코르빅 산의 안정성 향상을 위해 ferulic acid와 caffeic acid를 아스코르빅산 수용액에 첨가하였다. 아스코르빅 산의 안정성 향상은 시간경과에 따른 SC50 값의 변화로부터 확인하였다. 아스코르빅 산을 ferulic acid 또는 caffeic acid와 조합하여 BGsome 안에 포집시켜본 결과, 아스코르빅 산의 안정성이 순수한 용액 상태로 있을 때에 비해 크게 향상되었다.
        4,000원
        15.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The synthesis of C60@MWCNT was carried out at room temperature (~25℃) from arc-discharge prepared Multi-wall carbon nanotubes (MWCNTs). They were oxidized and acid treated for tube opening. Then C60 molecules were encapsulated into MWCNTs by wetting them with C60-toluene solution for several minutes followed by ultrasonification. C60@MWCNT was cleaned by pure toluene to remove any excess C60. C60@MWCNT was characterized by electron microscopy, which showed large scale filling of C60 into MWCNTs. It was observed that the mechanism of insertion of C60 into MWCNTs may be due to the capillary suction at the opening ends of MWCNTs.
        3,000원
        16.
        2009.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 김치건조분말을 제조하는 과정에서 김치의 발효과정과 건조 전후에서 나타나는 향기성분의 변화를 조사하고, β-cyclodextrin의 첨가로 인한 향기성분 포집효과를 검증하고자 GC-MS를 이용하여 분석실험을 실시하였다. 김치를 제조하여 20oC에서 발효시켰을 때, 초기 2일째는 dimethyl sulfide와 carbon disulfide가 생성되었고, 7일이 경과하였을 때, dimethyl disulfide, methyl 2-propenyl disulfide, allyl methyl sulfide, and di-2-propenyl disulfide의 황화합물이 주된 향기성분으로 검출되었다. 본 김치시료를 감압건조 하였을 때, 11개 화합물이 검출되지 않았고 dimethyl sulfide, acetaldehyde and methanethiol를 주로 포함하는 13개 화합물이 잔류하였다. 건조공정 중에서 김치 향기성분의 손실을 최소화하고자 0.25-1.0% 농도의 β-cyclodextrin을 건조보조제로 첨가하였을 때, 향기성분의 포집효과에 의해 건조 김치분말에 잔류하는 향기성분의 함량이 평균 3% 증가하였다. 본 연구결과로 볼 때 cyclodextrin은 건조 김치분말 제조공정뿐만 아니라 건조식품제조에서 건조보조제로 효과적으로 사용할 수 있을 것으로 보인다.
        4,000원
        20.
        2001.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A series of microcapsule were synthesized by using several PCM(Phase Change Material) as a core material and gelatin/arabic gum, melamine/formaldehyde as a shell material. Coacervation technique and in situ polymerization were adopted in synthesizing microcapsules. In the microencapsulation by coacervation, tetradecane and octadecane were used as core materials. In the microencapsulation by situ polymerization tetradecane, pentadecane, hexadecane, heptadecane, octadecane, and nonadecane were used as core material. The synthesized microcapsule was examined to observe the shape of the microcapsule. The particle size analysis was performed by particle size analyzer. The thermal properties(e.g. melting point, heat of melting, crystallization temperature, heat of crystallization, differences between melting point and crystallization temperature) were obtained by DSC(Differential Scanning Calorimeter). The stirring rate effect was investigated during the microencapsulation. It was found that with increasing the stirring rate much smaller microcapule was produced. However, this did not necessarily lead to formation of spherical microcapsule.
        4,300원
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