• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.414-419
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• 1995

${\beta}-carotene$ was extracted from freeze-dried carrot by supercritical carbon dioxide $(SC-CO_2)$ and mixtures of $CO_2$ doped with ethanol or methanol as a cosolvent at temperatures of 40 to $60^{\circ}C$ and pressures of 138 to 276 bar. Solubility of ${\beta}-carotene$ in $SC-CO_2$ increased with the increase of extraction pressure and the decrease of extraction temperature. The highest solubility observed was $4.90\;{\mu}g/g\;CO_2\;for\;{\alpha}-carotene\;and\;0.604\;{\mu}g/g\;CO_2$ for ${\alpha}-carotene\;at\;40^{\circ}C$ and 276 bar. Addition of ethanol increased the solubility being the largest increase of 82% using a mixture of $CO_2$ and 17.4% ethanol. $SC-CO_2$ extraction can be used to selectively obtain natural carotenoids, free of solvent residuals, which can be used as food additives.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.860-865
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• 1997

Investigations were performed on the effects of extraction temperature, pressure, time on solubility and selectivity of egg yolk lipid and cholesterol, and color and fatty acid composition of the residue in supercritical carbon dioxide(SC-Co$_2$) extraction. Lipid and cholesterol solubility increased as the increase of Co$_2$ density and was found to strongly depend on the extraction pressure rather than the extraction temperature. The relative concentration of cholesterol in the extract increased with an increase in temperature and decreased with an increase in pressure and extraction time. extraction of dried eg yolk for 3hr at 4$0^{\circ}C$/276 bar removed 46.1% of cholesterol from the residual egg yolk with a yield of 63.2%. SC-Co$_2$ extraction produced a lighter color egg yolk with less redness and yellowness. As the extraction time increased, the resultant residual egg yolk became more saturated with fatty acids. SC-$CO_2$ extraction offers a safe, natural method for removing cholesterol from dried egg yolk.

• Polymer(Korea)
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• v.34 no.6
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• pp.553-559
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• 2010

The paper describes the preparation and characterization of conductive polyaniline-modified polymers by growing of aniline onto functionalized poly(styrene-co-p-methylstyrene) [P(St-co-MSt)]. For this purpose, P(St-co-MSt) was synthesized via nitroxide mediated radical polymerization (NMRP) and then N-boromosuccinimide was used for introduction of bromine to the benzylic positions of copolymer. Afterwards, 1,4-phenylenediamine was linked to the brominated P(St-co-MSt) and functionalized copolymer $[P(St-co-MSt)-NH_2]$ was prepared. The graft copolymerization of aniline monomers onto functionalized P(St-co-MSt) was initiated by oxidized phenylamine groups after addition of ammonium peroxydisulfate (APS), and p-toluenesulfonic acid-doped PANI was chemically grafted onto P(St-co-MSt) via oxidation polymerization. The obtained terpolymer was studied by FTIR and UV-Vis spectroscopy and its thermal behaviour were examined by DSC and TGA analyses. The conductivity of terpolymer was measured by four-point probe method and electroactivity was measured by cyclic voltammetry (CV). The solubility of P(St-co-MSt)-g-PANI was examined in common organic solvents.

• Journal of Environmental Science International
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• v.5 no.4
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• pp.535-544
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• 1996

In the development of Molten Carbonate Fuel Cell, one of the serious problems is the dissolution of cathode material. Therefore, the development of the alternative cathode which is stable in molten carbonate is needed. In this research, the licoo, was chosen as alternative cathode material. $LiCoO_2$ powder was synthesized by high temperature calcination method and by citrate sol-gel method. And its structure and physical iharacteristics were analyzed by XRD, 1 R, TCA and porosimeter. The conductivity and solubility of $LiCoO_2$ electrode were also measured. Homogeneous $LiCoO_2$ Powder was obtained by citrate sol-Rel method at 445$^{\circ}C$, however, obtained above 75$0^{\circ}C$ by high temperature calcination method. Homogeneous particle size distribution and fine powder were obtained by the citrate sol-Rel method. $LiCoO_2$ electrode showed higher electric conductivity ($1.7 $\Omega$^{-1}cm^{-1}$) than NiO (0.1 $\Omega$^{-9} cm^{-1}) at $650^{\circ}C$. The solubilities of $LiCoO_2$ electrode in electrolyte were varies 0.6 to 1.0 ppm during 200 hours. So, the solubilities of $LiCoO_2$ were much lower than that of NiO.

• Fibers and Polymers
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• v.3 no.1
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• pp.1-7
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• 2002

Cellulose carbonate was prepared by the reaction of cellulose pulp and $CO_2$ with treatment reagents, such as aqueous $Zncl_2$ (20-40 wt%) solution, acetone or ethyl acetate, at -5-$0^{\circ}C$ and 30-40 bar ($CO_2$) for 2 hr. Among the treatment reagents, ethyl acetate was the most effective. Cellulose carbonate was dissolved in 10% sodium hydroxide solution containing zinc oxide up to 3 wt% at -5-$0^{\circ}C$. Intrinsic viscosities of raw cellulose and cellulose carbonate were measured with an Ubbelohde viscometer using 0.5 M cupriethylenediamine hydroxide (cuen) as a solvent at $20^{\circ}C$ according to ASTM D1795 method. The molecular weight of cellulose was rarely changed by carbonation. Solubility of cellulose carbonate was tested by optical microscopic observation, UV absorbance and viscosity measurement. Phase diagram of cellulose carbonate was obtained by combining the results of solubility evaluation. Maximum concentration of cellulose carbonate for soluble zone was increased with increasing zinc oxide content. Cellulose carbonate solution in good soluble zone was transparent and showed the lowest absorbance and the highest viscosity. The cellulose carbonate and its solution were stable in refrigerator (-$5^{\circ}C$ and atmospheric pressure).

• Journal of the Semiconductor & Display Technology
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• v.4 no.4 s.13
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• pp.13-17
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• 2005

The behavior of ozone in $NH_4OH$ was investigated to evaluate the solution as a cleaning chemical of the silicon wafer. The solubility of ozone in DI(Deionized) water increased as the oxygen flow-rate decreased and ozone generator power increased. Ozone in DI water showed solubility of 100 ppm or higher at room temperature. Ozone concentration was stabilized at the range of ${\pm}2ppm$ by controlling oxygen flow rate and ozone generator power. On the contrary, the solubility of ozone in $NH_4OH$ was very low and strongly depended on the concentration of $NH_4OH$ and pH. The redox potential of ozone was saturated within 10 minutes in DI water and decreased rapidly with the addition of $NH_4OH$. The behavior of ozone in $NH_4OH$ is well explained by redox potential calculation.

• Korea-Australia Rheology Journal
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• v.18 no.2
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• pp.83-90
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• 2006

Supercritical carbon dioxide ($scCO_2$) has advantages of being incorporated in polymer with high solubility and of being recovered easily by depressurizing. $scCO_2$ reduces the viscosity of polymer melt and it is expected to be use as a plasticizing agent. In this work, we studied on the effect of $scCO_2$ on the rheological properties of polymer melts during extrusion process. Slit die attached to twin screw extruder was used to measure the viscosity of polymer melts plasticized by supercritical $CO_2$. A gas injection system was devised to accurately meter the supercritical $CO_2$ into the extruder barrel. Measurements of pressure drop within the die, confirmed the presence of a one phase mixture and a fully developed flow during the measurements. The viscosity measurement of polypropylene was performed at experimental conditions of various temperatures, pressures and $CO_2$ concentrations. We observed that melt viscosity of polymer was dramatically reduced by $CO_2$ addition.

• Korean Journal of Materials Research
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• v.21 no.8
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• pp.450-455
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• 2011

[ $Al_2TiO_5$ ]has a high refractive index and good solubility of the chromophore in the $Al_2TiO_5$ lattice, which allows this structure to be a good candidate for the development of new ceramic pigments. However, pure $Al_2TiO_5$ is well known to decompose on firing at $900{\sim}1100^{\circ}C$. However, this process can be inhibited by the incorporation of certain metal cations into its crystalline lattice. In this study, the synthesis of gray ceramic pigment was performed by doping cobalt on the $Al_2TiO_5$ crystal structure. The $Al_2TiO_5$ was synthesized using $Al_2O_3$ and $TiO_2$, and doped with $Co_3O_4$ as a chromophore material. In order to prevent the thermal decomposition during the cooling procedure, MgO was added to samples by 0.05 mole, 0.1 mole, and 0.15 mole as a stabilizer. The samples were fired at $1500^{\circ}C$ for 2 hours and cooled naturally. The crystal structure, solubility limit, and color of the synthesized pigment were analyzed using XRD, Raman spectroscopy, UV, and UV-vis. $Al_2O_3$ was available for the formation of $CoAl_2O_4$, which should also be considered in order to explain the small amount of this phase detected in the sample with the higher $Co^{2+}$ content (${\geq}$ 0.03 mole). It was found that the solubility limit of $Co^{2+}$ in the $Al_2TiO_5$ crystal was 0.02 mole% through an analysis of Raman spectroscopy. Through the addition of a pigment with 0.02 mole% of $Co^{2+}$ to lime-barium glaze, stabilized gray color pigments with 66.54, -2.35, and 4.68 as CIE-$L^*a^*b^*$ were synthesized.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.3
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• pp.145-151
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• 2023

In order to extend shelf life for rockfish fillets by modified atmosphere packaging (MAP), different package atmospheres were compared in the product quality preservation. Firstly, CO₂ solubility was measured at 0, 5, 10, and 15℃ to be incorporated into the mathematical model to predict the volume and CO₂ concentration of the package at expected storage temperature. The CO₂ solubility given in Henry's constant decreased with temperature to be fitted with a linear equation. Then air packaging as control and four MAP conditions of 100 g fillets were prepared and stored for duration of 5 days at 10℃ to compare them in the quality preservation effect. Four MAP conditions employed were CO₂(60):O₂(30):N₂(10), CO₂(60):O₂(0):N₂(40), CO₂(30):O₂(30):N₂(40) andCO₂(30):O₂(0):N₂(70). MAP conditions with high CO₂ concentration inhibited total aerobic bacteria, and the conditions containing O₂ led to low TVB-N. MAP of CO₂(60):O₂(30):N₂(10) was found to be the best condition for rockfish fillet preservation considering total aerobic bacteria growth and nitrogenous volatiles production.

• Bulletin of the Korean Chemical Society
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• v.30 no.8
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• pp.1749-1754
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• 2009

Solubilities of carbon dioxide (C$O_2$) in a series of fluorine-free room temperature ionic liquids (RTILs), dialkylimidazolium dialkylphosphates and dialkylimidazolium alkylphosphites, were measured at 313∼333 K and pressures up to 5 MPa. Henry’s law coefficients as the solubility parameter of C$O_2$ in RTILs were derived from the isotherm of fugacity versus C$O_2$ mole fraction. The C$O_2$ solubility in a phosphorus-containing RTIL was found to increase with the increasing molar volume of the RTIL. In general, dialkylimidazolium dialkylphosphate exhibited higher absorption capacity than dialkylimidazolium alkylphosphite as long as the RTILs possess an identical cation. Among RTILs tested, 1-butyl-3-methylimidazolium dibutylphosphate [BMIM][B$u_2PO_4$] and 1-butyl-3-methylimidazolium butylphosphite [BMIM][BuHP$O_3$] exhibited similar Henry’s law coefficients to 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide ([BMIM][T$f_2$N]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][B$F_4$]), respectively. The Krichevsky-Kasarnovsky equation was employed to derive the C$O_2$ solubility parameter (Henry’s law coefficient) from the solubility data measured at elevated pressures.