• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.7
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• pp.1018-1023
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• 2010

This study was conducted to investigate quality changes of apple slab after pretreating with supercritical $CO_2$. L, a, b and color difference values were little changed at increasing temperature and pressure. Polyphenol oxidase was inhibited according to increment of supercritical $CO_2$ temperature and pressure. Springiness and hardness were increased at increasing pressure and temperature condition of pretreatment but hardness showed lower value than untreatment. The texture like sponge of dried apple slab was probably due to channels which were made during penetration and release of carbon dioxide.

• Food Science and Preservation
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• v.17 no.2
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• pp.256-260
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• 2010

We investigated changes in the chemical composition of apple slices after pretreatment with supercritical $CO_2$. Total phenolic levels increased with increasing temperature, although the concentrations were lower in pretreated material than in fresh or untreated slices. The levels of vitamin C and malic acid in pretreated slices were also lower than in untreated or fresh apple slices. Little difference was evident among various pretreatmentconditions. It was found that supercritical $CO_2$ served not as a solvent but rather as a means of tissue compression. Supercritical $CO_2$ compressed the apple slices, causing juice to be extruded. The juice disappeared when the supercritical $CO_2$ pressure was released.

• Clean Technology
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• v.24 no.1
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• pp.1-8
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• 2018

As the social demands for environmental pollution increase and regulations on the dyeing process wastewater are strengthened, supercritical dyeing process has been attracting attention as an alternative technology to reduce wastewater and energy consumption. In the supercritical dyeing process where carbon dioxide is used as a solvent instead of water as a solvent, there is no wastewater generated. The unfixed dyes can be reused later which makes the process environment-friendly. Also, after dyeing process, dried textiles can be obtained without additional drying process, which makes the process energy efficient. In this article, we have summarized the development of the supercritical dyeing process along with the research in Korea today and compared the principle of supercritical dyeing process with conventional dyeing process. To further explain the principle, studies of the distribution factor and mass transfer of dyes in supercritical carbon dioxide and fibers, as well as solubility between supercritical $CO_2$ and dyes are discussed. The dynamic behavior of dyes in supercritical dyeing apparatus and summary of the supercritical dyeing facilities developed around the world are also discussed. Finally, we suggest the direction of research and development for optimization of supercritical dyeing process and application to synthetic fibers and natural fibers except for polyester.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.741-746
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• 2010

Phospholipids were recovered from squid viscera residues by ethanol extraction after supercritical carbon dioxide($SCO_2$) extraction and from squid viscera was not processed $SCO_2$ by various organic solvent extraction. $SCO_2$ extraction were performed at $45^{\circ}C$ and 20 MPa for removal of non polar lipid molecules from freeze dried squid viscera sample. Phospholipids were extracted from freeze dried squid viscera sample by chloroform, hexane, methanol, and ethanol and from $SCO_2$extracted squid viscera sample by ethanol. The pH was fixed at 5.7 for all phospholipids extraction conditions. Phospholipid classes were analyzed by HPLC equipped with evaporative light scattering detector (ELSD). Phosphatidyl choline(PC) extracted by ethanol from $SCO_2$ extracted residues was higher than that of extracted by ethanol from squid viscera. But phosphatidyl ethanolamine(PE) and phosphatidic acid(PA) were extracted higher percentage in raw squid viscera. The fatty acid compositions in phospholipids extract by ethanol extract from $SCO_2$ extracted residues were analyzed by gas chromatography(GC). Docosahexanoic acid(DHA) was found in highest percentage in phospholipid extract.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.140.2-140.2
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• 2007

• 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.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.516-519
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• 2000

Generally pancreas consist of lipid, water and protein, digestion enzyme complex (pro-tease, lipase, amylase). The sample used in this work was frozen dry and treated by a semi-batch flow type. In order to develop a supercritical fluid extraction process to rem-ove lipid from the pancreas, experiments were conducted at various operating conditions(pressure range $1500{\sim}2800psi$, temperature range $25{\sim}40^{cdot}C$, particle size$(0.25{\sim}1.0mm$, flow rate $20{\sim}80m{\ell}/min)$. Also cholesterol in the pancreas was removed. The highest extraction efficiency was 2500psi, $35^{\cdot}C$, 0.25mm of pancreas size. The enzyme activity of the pancreas produced from this work showed high value compared with imported pancreas.

• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.557-564
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• 2015

The previous etching, rinsing and drying processes of wafers for MEMS (microelectromechanical system) using SC-$CO_2$ (supercritical-$CO_2$) consists of two steps. Firstly, MEMS-wafers are etched by organic solvent in a separate etching equipment from the high pressure dryer and then moved to the high pressure dryer to rinse and dry them using SC-$CO_2$. We found that the previous two step process could be applied to etch and dry wafers for MEMS but could not confirm the reproducibility through several experiments. We thought the cause of that was the stiction of structures occurring due to vaporization of the etching solvent during moving MEMS wafer to high pressure dryer after etching it outside. In order to improve the structure stiction problem, we designed a continuous process for etching, rinsing and drying MEMS-wafers using SC-$CO_2$ without moving them. And we also wanted to know relations of states of carbon dioxide (gas, liquid, supercritical fluid) to the structure stiction problem. In the case of using gas carbon dioxide (3 MPa, $25^{\circ}C$) as an etching solvent, we could obtain well-treated MEMS-wafers without stiction and confirm the reproducibility of experimental results. The quantity of rinsing solvent used could be also reduced compared with the previous technology. In the case of using liquid carbon dioxide (3 MPa, $5^{\circ}C$, we could not obtain well-treated MEMS-wafers without stiction due to the phase separation of between liquid carbon dioxide and etching co-solvent(acetone). In the case of using SC-$CO_2$ (7.5 Mpa, $40^{\circ}C$), we had as good results as those of the case using gas-$CO_2$. Besides the processing time was shortened compared with that of the case of using gas-$CO_2$.

• Proceedings of the Materials Research Society of Korea Conference
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• 1995.11a
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• pp.127-127
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• 1995

• KSBB Journal
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• v.20 no.5 s.94
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• pp.383-386
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• 2005

Grape seed oil made by press or organic solvent extraction does not contain resveratrol, a bioactive compound. Supercritical carbon dioxide could extract oil containing resveratrol from grape seed. The extraction efficiency was mainly dependent on the water content in grape seed. More resveratrol was contained in the oil extracted with un-dried grape seed. No resveratrol was extracted with dried grape seed. Time course changes of grape seed oil extraction also resulted that resveratrol could be extracted by supercritical carbon dioxide with the positive influence of water.