• KSBB Journal
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• 제19권4호
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• pp.284-287
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• 2004

초임계 이산화탄소를 이용하여 가시오갈피로부터 유용성분인 acanthoside-D를 추출하여 다음과 같은 결론을 유추하였다. 에탄올과 물, 그리고 50% 메탄올을 공용매로 사용하여 일정압력과 온도에서 추출한 결과물에서의 수율이 가장 높게 측정되었으며, 압력의 변화에 따른 acanthoside-D의 추출효율을 비교한 결과 300 bar에서 가장 높은 추출효율을 나타내었다. 또한 50% 메탄올을 공용매로 하여 유량을 변화시킨 결과, 높은 유량에서 높은 수율을 나타내었으나 1.5ml/g 이상의 유량에서는 수율의 변화가 없었다.

• KSBB Journal
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• 제27권2호
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• pp.131-135
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• 2012

To develop potential cosmetic ingredients with antimicrobial and antioxidant activities of 4 Korean bamboo species (P. bambusoides, P. nigra var. henonis, P. pubescens and Sasa coreana) using three different extraction methods-water, ethanol and supercritical fluid extraction. Antimicrobial activities and DPPH assay have been examined. Among the antimicrobial activities against two test strains, Escherichia coli and Staphylococcus aureus, ethanol extracts of 3 bamboo trees, P. bambusoides, P. nigra var. henonis, and P. pubescens, showed stronger than those of supercritical extracts. However, 4 bamboo supercritical extracts showed dose-dependent increase in antioxidant activity by DPPH assay. These results suggest that water fraction of bamboo extracts may be useful for the cosmetic ingredient with low cytotoxicity.

• KSBB Journal
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• 제19권6호
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• pp.421-426
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• 2004

토종콩으로부터 비배당체 이소플라본을 추출하기 위한 다양한 기계적 및 화학적 방법을 적용하였다. 용매추출법의 침적과 교반, 초음파에너지와 아임계/초임계 수 추출이 포함되었다. 용매의 조성에 의한 추출효율의 증가, 교반에 의한 특정성분의 추출효과의 증대, 초음파에너지에 의한 추출성능의 개선, 용매보다 용해력이 좋은 초임계유체의 적용에 관한 실험을 수행한 결과에 의하면 비배당체 이소플라본의 추출은 초음파에너지에 의한 것이 가장 우수하였다.

• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3597-3611
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• 2021

The present paper studies the thermal-hydraulic behaviour of the rectangular supercritical natural circulation loop (SCNCL) using numerical model of one dimensional. Then the results of this model is confirmed with experimental and benchmark results. Variations with several geometric parameters like loop diameter, riser length, and heater length and operating conditions like heater inlet enthalpy, pressure, friction factor, and inlet and exit loss coefficient on steady-state performance are investigated for various orientations like HHHC, HHVC, VHVC and VHHC of the heater and cooler. The chances of existing static instability (Ledinegg excursion) has been investigated, which reveals that it can arise only in a low inlet enthalpy condition, far from the suggested various orientations of heater and cooler.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3395-3400
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• 2007

Heat transfer experiments at a vertical annulus passage were carried out in the SPHINX(Supercritical Pressure Heat Transfer Investigation for NeXt Generation) to investigate the heat transfer behaviors of supercritical $CO_2$. The collected test data are to be used for the reactor core design of the SCWR (SuperCritical Water-cooled Reactor). The mass flux was in the range of 400${\sim}$1200 kg/$m^2$s and the heat flux was chosen up to 150 kW/$m^2$. The selected pressures were 7.75 and 8.12 MPa. The heat transfer data were analyzed and compared with the previous tube test data. The test results showed that the heat transfer characteristics were similar to those of the tube in case of a normal heat transfer mode and degree of heat transfer deterioration became smaller than that in the tube. Comparison of the experimental heat transfer coefficients with the predicted ones by the existing correlations showed that there was not a distinct difference between the correlations.

• KSBB Journal
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• 제20권5호
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• pp.383-386
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• 2005

압착이나 유기용매 추출방식으로 생산된 포도씨유에는 resveratrol이 함유되어있지 않다 초임계 이산화탄소로 추출하는 경우 포도씨에 존재하는 resveratrol의 약 $1.6\%$가 추출 함유됨을 확인하였다. 초임계 추출 효율은 포도씨 건조 정도에 따라서 달라졌는데, 시료에 수분이 전혀 있지 않은 경우는 resvertrol을 추출되지 않았다. 수분함량이 증가할수록 추출 효율이 증가하는데, 수분이 resvertrol을 추출에 중요한 역할을 하였다. 초임계유체 추출 시간에 따른 추출된 포도씨 유의 resvertol 함량은 초반보다 후반으로 갈수록 증가하는 경향을 나타내었다. 초반에 오일 이 많이 추출되고 이후 수분이 빠져나오는 추출성향을 볼 때, resvertrol추출에는 수분이 초임계유체의 성질에 큰 영향을 미쳐 추출 효율을 변화시키는 것으로 생각된다.

• Archives of Pharmacal Research
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• 제23권2호
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• pp.163-166
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• 2000

The effects of modifiers such as methanol, water diethylamine in methanol (10 v/v %), and diethylamine in water (10 v/v %) were investigated at three different concentrations (1, 5, and 10 v/v %) of the modifiers in supercritical $CO_2$ (SC-$CO_2$) in order to enhance the supercritical fluid extraction (SFE) efficiency of cephalotaxine from Cephalotaxus wilsoniana Leaves. Among the modifiers employed, methanol basified with diethylamine was found to greatly enhance the extraction efficiency relative to any other modifiers employed. The results suggest that cephalotaxine in plant matrices may be readily changed from SC-$CO_2$-insoluble salt to SC-$CO_2$-soluble free base by basified modifiers. In addition, SC-$CO_2$modified with basified methanol could enhance the extraction efficiency of cephalotaxine more than 30% when compared to the conventional organic solvent extraction.

• KSBB Journal
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• 제16권4호
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• pp.327-331
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• 2001

전라남도 보성산 녹차로부터 유용성분인 카테킨 화합물을 초임계 이산화 탄소와 첨가제를 사용하여 추출하고 역상 고성능 액체 크로마토그래피(RP-HPLC)를 사용하여 분석하였다. LiChrospher 100RP-18(15 $\mu$m)로 충진된 column을 이용하여 0.05% phosphoric acid가 포함된 물과 acetonitrile을 이동상으로 사용하였으며 구배용매 조성법을 적용하였다. 이동상의 조성에 따른 체류인자의 조절을 통해 EGCG를 분리하였다. 각각의 초임계 추출법에 따른 EGCG의 추출량을 비교한 결과, 초임계 유체에 극성물질을 포함하는 경우가 녹차의 유용 성분인 EGCG의 추출량이 가장 많았다. 그러나 ethanol에 의한 용매 추출법은 초임계 유체에 의한 추출법보다 EGCG에 대해 많은 추출양과 선택적인 고순도 분리가 가능하였다.

• Nuclear Engineering and Technology
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• 제40권2호
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• pp.155-162
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• 2008

Heat transfer experiments in an annulus passage were performed using SPHINX(Supercritical Pressure Heat Transfer Investigation for NeXt Generation), which was constructed at KAERI(Korea Atomic Energy Research Institute), to investigate the heat transfer behaviors of supercritical $CO_{2}$. $CO_{2}$ was selected as the working fluid to utilize its low critical pressure and temperature when compared with water. The mass flux was in the range of 400 to 1200 $kg/m^{2}s$ and the heat flux was chosen at rates up to 150 $kW/m^{2}$. The selected pressures were 7.75 and 8.12 MPa. At lower mass fluxes, heat transfer deterioration occurs if the heat flux increases beyond a certain value. Comparison with the tube test results showed that the degree of heat transfer deterioration in the heat flux was smaller than that in the tube. In addition, the Nusselt number correlation for a normal heat transfer mode is presented.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.877-887
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• 2022

A new reactor concept is described that directly couples a supercritical CO₂ (sCO₂) power cycle with a CO₂-cooled, heavy water moderated pressure tube core. This configuration attains the simplification and economic potential of past direct-cycle sCO₂ concepts, while also providing safety and power density benefits by using the moderator as a heat sink for decay heat removal. A 200 MWe design is described that heavily leverages existing commercial nuclear technologies, including reactor and moderator systems from Canadian CANDU reactors and fuels and materials from UK Advanced Gas-cooled Reactors (AGRs). Descriptions are provided of the power cycle, nuclear island systems, reactor core, and safety systems, and the results of safety analyses are shown illustrating the ability of the design to withstand large-break loss of coolant accidents. The resulting design attains high efficiency while employing considerably fewer systems than current light water reactors and advanced reactor technologies, illustrating its economic promise. Prospects for the design are discussed, including the ability to demonstrate its technologies in a small (~20 MWe) initial system, and avenues for further improvement of the design using advanced technologies.