• KSBB Journal
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• v.19 no.4
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• pp.263-268
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• 2004

The separation method using chiral stationary phase in preparation of chiral compound was wildly used, but in this work, supercritical fluid chromatography was suggested in the stability to resolve the chiral mixtures. To determine the optimum operating condition of the racemic ibuprofen, the retention factor and resolution with change in pressures, temperatures and the contents of IPA % (vol.) in CO$_2$ were investigated. The retention factor was decreased with increase in pressure and decrease in temperature. The factor was also influenced by the content of IPA in mobile phase, while the resolution was worse with a increase in IPA %. From the experimental results, the desirable separation condition was 130 bar, 311.15 K and 4% IPA in CO$_2$. Compared to the asymmetric peak shape by liquid chromatography, that of supercritical fluid chromatography was symmetric which was a favorable condition for preparative separation.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.447-455
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• 2008

Recombinant yeast estrogenicity (YES) assay was used as a bioanalytical tool in order to screen $17{\beta}$-estradiol in the soil samples collected from different sites of South Korea. Solvent extraction and supercritical fluid extraction (SFE) methods were compared for the extraction of the estradiol from the soils. Most high detection of the estradiol based on YES assay was observed in the soils extracted with methanol. Different types of estrogenic hormones including $17{\beta}$-estradiol were suggested to be possibly exiting in the soils, since the methanol extracts of the soils showed an estrogenic activity that was not observed in the hexane extracts of the soil. SFE extracts showed estrogenic activity in some of the samples but methanol extract showed best activity.

• Elastomers and Composites
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• v.47 no.2
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• pp.111-120
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• 2012

Industrial wastes of crosslinked polymers have been burned or disposed of in landfills because there is no recycling technology due to their insoluble and infusible network chain structure. However, recycling of cross-linked polymers has been taken a growing attention because of issues of environmental pollution and of resources conservation. In this paper, uprising recycling technologies of crosslinked polymers using supercritical fluid are reviewed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.150-155
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• 2010

Liquid rocket injectors play crucial roles on propulsive performance, combustion stability, and heat transfer characteristics. Nevertheless, their developments have mainly relied on empirical methods and expensive hot-firing tests due to lack of fundamental understanding of high pressure combustion phenomena in the near-injector regions. The present study was motivated by recent efforts to develop reliable modeling of liquid rocket combustion. The turbulent combustion model based on the flamelet concept has been extended to take into account real-fluid behaviors occurred at supercritical pressures, and validated against measurements for a cryogenic nitrogen injection, a non-premixed turbulent jet flame at atmospheric pressure, and a LOx/$GH_2$ coaxial shear injector at a supercritical pressure.

• The Journal of Engineering Research
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• v.4 no.1
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• pp.87-91
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• 2002

Nano-size Alumina powders were prepared by heat treatments which were products obtained using supercritical drying and fluid method. Al-isopropoxide dispersed in ethylene glycol as solvents were used as starting materials. The alumina powders were made by supercritical drying fluid method at Autoclave, those were characterize examined closely by XRD, SEM and TG-DTA. The powders were transformed $\alpha-A12O3$ in new route after heat treatment.

• Food Science and Biotechnology
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• v.27 no.6
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• pp.1857-1864
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• 2018

Phthalate plasticizers residue in food is a serious threat to public health. Spores of Ganoderma lucidum are easy to be contaminated with phthalates during collection and processing. In this study, supercritical fluid extraction (SFE) was performed to remove phthalates in spores of G. lucidum, and the effects on acid and peroxide values of spores' oil were also evaluated. The results showed SFE removed 100% of the residual di-iso-butyl phthalate, di-n-butyl phthalate and di-2-ethylhexyl phthalate in the spores of G. lucidum. No significant differences in polysaccharides content and fatty acid composition were observed between SFE and control spores. However, the triterpenoid extracts of SFE spores had a 7.45% increase, significantly higher than that in control spores. Accelerated oxidation tests further implied that SFE could improve the stability of spores' oil. Our results suggested SFE is a potential approach to remove phthalate from food related products.

• Nuclear Engineering and Technology
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• v.40 no.2
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• pp.107-116
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• 2008

The present paper describes the preliminary compilation, assessment and examination of the supercritical heat transfer(SCHT) database. The availability and reliability of the SCHT data are discussed. Similarities in thermodynamic supercritical properties and SCHT behaviour of water, $CO_{2}$ and R-134a have been examined and some tentative conclusions are made. Finally, the future experimental and analytical program at the University of Ottawa is described.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.220-224
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• 2017

In this study, we investigated a new recycling method of phenol resin, which is widely used to make electric insulation boards and adhesives, into carbon particles by using supercritical fluids. Because phenol resin is insoluble and infusible, most of the phenol resin wastes are buried in the ground or incinerated, which leads to environmental pollution. Therefore, development of a new method to recycle phenol resin waste is an urgent issue. In this study, phenol resin waste was treated with four sub/supercritical solvents: ethanol, acetone, water, and methanol. For all the sub/supercritical solvents, the phenol resin wastes were broken down into carbon nano particles at much lower temperatures than that required in the existing carbon particle manufacturing processes. We investigated the difference of morphologies and physical properties of recycled carbon particles according to the use of various solvents. As a result, carbon nano particles with the same amorphous structure were obtained from phenol resin waste with the usage of various sub/supercritical solvents at much lower temperature.

• Journal of the Korea Convergence Society
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• v.9 no.8
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• pp.225-233
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• 2018

The Ulmus davidiana have been used in traditional oriental medicine as remedies for inflammation, ulcers, cancers, bacterial infections and scabies. In this study, the anti-fungal, anti-oxidant, and anti-inflammatory activitiesof a supercritical extract of U. davidiana were investigated in vitro. To explore the anti-oxidant and anti-inflammatory characteristics of the supercritical extract, ABTS radical scavenging activity, and the inhibition of nitric oxide production in LPS-stimulated RAW 264.7 cells were examined, respectively. In addition, the anti-fungal activities of the extract were assessed. The results showed a concentration-dependent increase in ABTS radical scavenging activity. Cells stimulated with LPS produced more nitric oxide than normal control cells; however, cells treated with the supercritical fluid extract decreased this production in a concentration-dependent manner. Finally, the supercritical fluid extracts showed significant anti-fungal activity. These results suggest that extracts of the U. davidiana might be used to develop potent anti-fungal, anti-oxidant, and anti-inflammatory agents, and may be useful as ingredients for related new functional cosmetic materials.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.46-51
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• 2007

In this study, computer simulations have been performed for the removal of the transformer oil contaminated with polychlorinated biphenyls (PCBs) in supercritical water through complete combustion reaction. We regarded n-decane as a main material of transformer oil, and it is assumed to be 3.0 wt％ of transformer oil in supercritical water. We used Peng-Robinson equation of state to estimate the physical properties of components in supercritical water. Throughout the computer simulation done in this work, we could explain the solubilities of 3.0 wt% of transformer oil and excess oxygen in supercritical water.