• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.167-174
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• 2008

In this study, flutter analyses for supercritical airfoil have been conducted in transonic region. Advanced computational analysis system based on computational fluid dynamics (CFD) and computational structural dynamics (CSD) has been developed in order to investigate detailed static and dynamic responses of supercritical airfoil. Reynolds-averaged Navier-Stokes equations with Spalart-Allmaras (S-A) and SST ${\kappa}-{\omega}$ turbulence models are solved for unsteady flow problems. A fully implicit time marching scheme based on the Newmark direct integration method is used for computing the coupled aeroelastic governing equations of cascades for fluid-structure interaction (FSI) problems. Also, flow-induced vibration (FIV) analyses for various supercritical airfoil models have been conducted. Detailed flutter responses for supercritical are presented to show the physical performance and vibration characteristics in various angle of attack.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.2
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• pp.8-17
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• 2009

In this study, flutter analyses for supercritical airfoil have been conducted in transonic region. Advanced computational analysis system based on computational fluid dynamics (CFD) and computational structural dynamics (CSD) has been developed in order to investigate detailed static and dynamic responses of supercritical airfoil. Reynolds-averaged Navier-Stokes equations with Spalart-Allmaras (S-A) and SST ${\kappa}-{\omega}$ turbulence models are solved for unsteady flow problems. A fully implicit time marching scheme based on the Newmark direct integration method is used for computing the coupled aeroelastic governing equations of cascades for fluid-structure interaction (FSI) problems. Also, flow-induced vibration (FIV) analyses for various supercritical airfoil models have been conducted. Detailed flutter responses for supercritical are presented to show the physical performance and vibration characteristics in various angle of attack.

• 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.

• Journal of the Korean Ceramic Society
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• v.39 no.11
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• pp.1023-1027
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• 2002

In this paper, we have prepared phase-pure $SrTiO_3:\;Pr^{3+}$ phosphor powder by Supercritical Fluid Mixing using $Sr(OH)_2{\cdot}8H_2O$ and $TiO_2$ powders as starting materials. Its luminescent properties were investigated in comparison with $SrTiO_3:\;Pr^{3+}$ powders prepared by solid-state method with conventional mixing. $SrTiO_3:\;Pr^{3+}$ phosphor powders by Supercritical Fluid Mixing have spherical shapes and narrow particle size distribution. We have investigated the luminescent properties of $SrTiO_3:\;Pr^{3+}$ phosphor using $Al^{3+}$ and $Ga^{3+}$ as sensitizer.

• Journal of Pharmacopuncture
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• v.11 no.1
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• pp.177-187
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• 2008

Objectives : This study was performed to analyze the effective components of essential oil obtained from Yongdamsagantang, which has been efficacious against leukorrhea in gynecologic diseases. Methods : I obtained the essential oils of Yongdamsagan-tang by hydrodistillation extraction method and supercritical fluid extraction(SFE) method, and then I analyzed those by GC/MS(Gas Chromatography/Mass Spectrum). Results : 1. The optimum SFE(Supercritical Fluid Extraction) condition was obtained in the following experiment conditions: pressure 200atm, temperature $45^{\circ}C$, duration of extraction 25minutes. 2. With GC(Gas Chromatography) and GC/MS(Gas Chromato- graphy/Mass Spectrum) analysis, I identified 37 compounds in the Yongdamsagan-tang's essential oil obtained through the SFE method. The main compounds were as follows : 3-Methyl-but-2-enoic acid,2,2-dimethyl-8-oxo-3,4-dihydro-2H,8H -pyrano[3,2-g]chromen-3-yl ester(49.81%), (Z)-6-Pentadecen-1 -ol(3.19%), (-)-Spathulenol(2.40%). 3. I identified 4 compounds in the Yongdamsagan-tang's essential oil obtained through the hydrodistillation method. The main compounds were as follows : 3-Methyl-but-2-enoic acid, 2,2-dimethyl-8-oxo-3,4-dihydro-2H,8H-pyrano [3,2-g]chromen-3-yl ester(2.61%). 4. 3-Methy I-but-2-enoic acid, 2,2-dimethyl-8-oxo-3,4-dihydro-2H,8H-pyrano[3,2-g] chromen-3-yl ester, all were identified in both the SFE method and the hydrodistillation method, but the others were not identified in common. 5. I also conducted an additional test in order to examine the essential oil's antimicrobial action against bacteria. Both MIC(Minimum Inhibitory Concentrations) and MBC(Minimum Bactericidal Concentrations) were $0.125mg/m{\ell}$ against N. meningitidis, however MIC and MBC were $1.0mg/m{\ell}$ in antimicrobial action against 12 different genera of bacteria.

• Analytical Science and Technology
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• v.5 no.2
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• pp.153-158
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• 1992

In this work, we developed supercritical fluid chromatographic methods for the samples which are difficult to analyze with conventional GC or HPLC. Long-chain Hydrocarbons, mink oils and soybean oils unsuitable for GC because of their low volatility or limited thermal stability were separated by SFC due to the high solvating properties of supercritical carbon dioxide fluids. In our research, a new method for the analysis of polar fatty acids and pesticides was developed. This method should be used to overcome problems with polar samples in SFC.

• Korean Journal of Pharmacognosy
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• v.50 no.3
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• pp.165-174
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• 2019

Oregonin is known as a representative active substance of plants of the Alnus species. In this study, we will show the results of establishing a method for extracting trace amounts of useful substances in plants. Additionally, a variety of physiological activity studies were conducted with extracts containing high content of useful substances. In this study, anti-oxidant, anti-inflammatory and anti-allergic activities of supercritical fluid residue 60% EtOH extracts of Alnus sibirica (ASCFR) were investigated in vitro. To explore anti-oxidant and anti-inflammatory characteristics of supercritical extract, DPPH radical scavenging, and ABTS radical scavenging activity, inhibition of nitric oxide production in LPS-stimulated RAW 264.7 cells and ${\beta}$-hexosaminidase release in IgE-stimulated RBL-2H3 cells were examined, respectively. Results showed a concentration-dependent increase in DPPH and ABTS radical scavenging activity. Cells stimulated with LPS produced more nitric oxide than normal control cells. However, cells treated with supercritical fluid residue 60% EtOH extract decreased production in a concentration-dependent manner. In anti-allergic activity studies, ASCFR showed concentration-dependentanti-allergic activity. Based on results and strong antioxidant activity, ASCFR has potential as basic research materials for development of therapeutic supplements-based medicines or functional cosmetics related to chronic inflammatory skin immunity diseases.

• Applied Biological Chemistry
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• v.41 no.5
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• pp.363-366
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• 1998

Supercritical fluid(SCF) carbon dioxide was used to extract safflower yellow pigments from Carthamus tinctorius L. In this work, supercritical fluid extractions were performed at various conditions; pressure (2000, 3000, 4000, 5000 psig), temperature $(40,\;50,\;60,\;70,\;80^{\circ}C)$ and co-solvent $(0,\;3,\;6,\;10,\;14\;wt%\;H_2O)$. Total concentrations of safflower yellow pigments extracted were determined by spectrophotometric method. A maximum yield of yellow pigments was obtained at 4000psig, $60^{\circ}C$ and 10% co-solvent. The extraction yield of pigments was also closely related to moisture content of the raw material. Extraction yield of safflower yellow pigments by SCF extraction at optimized conditions was 6% higher than that by solvent extraction. Supercritical carbon dioxide was proved to be suitable for the extraction of safflower yellow pigments from Carthamus tinctorius L.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1043-1052
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• 1996

Supercritical fluid chromatographic method was recommended as an alternative separation method of fatty acids of the conventional method such as distillation or extraction. Although diffusion characteristics are varied by the carbon numbers and the degree of unsaturation of fatty acids, the quantitative data were so rare that the commercialization of supercritical fluid chromatographic method has been hindered. In this study, diffusion coefficients of fatty acids which are differently unsaturated are measured by CPB method in the range of 308.15K to 328.15K and 13MPa to 17MPa in supercritical carbon dioxide. A decrease in the binary diffusion coefficient was observed with an increase in temperature and pressure. Also, the decrease in the binary diffusion coefficient with increasing fluid density and viscosity. Wilke-Chang equation, Funazukuri empirical equation, and Matthews-Akgerman equation are used to correlate the experimental diffusion coefficients of fatty acids in supercritical carbon dioxide. Among the various theoretical equations, Matthews-Akgerman equation based on RHS theory was suggested as a more successful correlation model with experimental data.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.09a
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• pp.117-121
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• 1998

The Rapid Expansion of supercritical fluid Solutions (RESS) process was applied to particles coating. Experiments were conducted in a fluidized bed with an internal nozzle in the center of the reaction tube. Microcapsules (mean particle size : 49$\mu\textrm{m}$) prepared by spray drying method were used as the core particles. Supercritical CO2 solutions of paraffin were expanded through the nozzle in to the bed that was fluidized by air. Surface morphology prepared particles was observed by SEM. For the inspection of particle size change, particle size distributions were measured before and after coating. The releasing behavior of Mg2+ ions inspected by AA.