• Journal of Conservation Science
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• v.29 no.3
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• pp.261-277
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• 2013

This study aims to research the relationship between whitewares and their rare materials from the site of Yanggu and Bunwon through the componential characteristic of the excavated whitewares from the 1st and the 2nd kilns of Chiljeon-ri in Bangsan-myeon, Yanggu-gun. As a result, the sherds were devided according to the chemical compositions of the body and the glaze via their respective production era. However, it considered that the whitewares from Chiljeon-ri had been manufactured with geochemically similar materials and the production process, such as refining and combining materials, had been different. It assumed that the firing temperatures of the whitewares from Chiljeon-ri were around $1,100-1,200^{\circ}C$ and substantially lower than for general whitewares. In the componential analysis, there were disparate properties in the cobalt pigment, which contained trace elements and rare earth elements. A review of the literature revealed a correlation between the whitewares from the late Chosun kiln site in Bunwon-ri and the raw materials from Yanggu-gun, but this was there were various techniques for refining and combining materials in Bunwon-ri.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.105-110
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• 2008

The high-purity purification of 2,6-dimethylnaphthalene (2,6-DMN, 10.43 wt%) from the concentrate of DMN isomers recovered from light cycle oil (LCO) through distillation-extraction combination was examined by a crystallization operation. To select the most suitable crystallization solvent for purification of 2,6-DMN, several conventional solvents, which have been employed commercially as crystallization solvents for high-purity performance, were tested, through measurement of purity and yield of 2,6-DMN. The solvents used were acetone, cyclohexanone, ethanol, ethyl ether, ethyl acetate, isopropyl ether, methanol, n-hexane, n-heptane, pyridine, THF, toluene, and a mixture of methanol and acetone. The mixture of 60 vol% methanol and 40 vol% acetone (M/A = 1.5) was found to be suitable for purification of 2,6-DMN in the concentrate of DMN isomers based on purity and yield. Increasing the operation temperature and the volume ratio of solvent (M/A = 1.5) to feed (concentrate of DMN) resulted in improving the purity of 2,6-DMN, whereas the yield decreased. The crystal recovered by crystallization run using the concentrate of DMN isomers contained about 76 wt% 2,6-DMN. Furthermore, for recovery of high-purity 2,6-DMN, crystal containing 76 wt% 2,6-DMN was crystallized. As a result, crystal with 99.7 wt% 2,6-DMN was recovered with 40% yield.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.869-876
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• 1996

Purification of 2,6-dimethylnaphthalene(2,6-DMNA) from the distillate containing a mixture of dimethylnaphthalene(DMNA) isomers of very high concentration was investigated by crystallization-recrystallization combination as a after-treatment for separation and purification of 2,6-DMNA in the light cycle oil(LCO). The separation of individual isomers of DMNA was studied by crystallization with the distillate as a feed. 2,6-DMNA, 2,7-dimethylnaphthalene(2,7-DMNA) and 2,3-dimethylnaphthalene(2,3-DMNA) were concentrated to crystal, and it was fould that separation between a group of 2,6-, 2,7-, 2,3-DMNA isomers and a group of the other DMNA isomers was possible. However, it was not possible to separate 2,6-, 2,7- and 2,3-DMNA from one another. To select the most suitable recrystallization solvent for purification of 2,6-DMNA, several conventional solvents, which have been employed commercially as recrystallization solvents for high purity performance, were tested, through measurement of solubility of 2,6- and 2,7-DMNA. The solvent used were hexane, iso-propyl ether, ethyl acetate and ethanol. From the solubility results for 2,6- and 2,7-DMNA, ethanol seemed to be the most suitable solvent for purification of 2,6-DMNA. Finally, with crystal recovered by crystallization as a feed and ethanol as a solvent, recrystallization experiments were conducted under various conditions. Purification of 2,6-DMNA was easily done with increasing operating temperature and solvent to feed ratio. These results show that the crystallization-recrystallization combination is an effective one for separation of individual isomers of DMNA.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.1
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• pp.1-8
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• 2023

This study focused on the development of a vegetable recombinated oil to mimic the animal-derived mink oil. Various vegetable oils and fatty acid substrates were mixed and an immobilized enzyme was utilized in the reaction to synthesize a plant-derived mink oil through deacidification and purification processes. The chemical composition and thermal properties of the recombined oil were confirmed using gas chromatography and differential scanning calorimetry. Our results show a high similarity between mink oil and our synthesized plant-derived mink oil, revealing the potential of utilizing vegetable alternatives for the substitution of animal raw materials, which have been gradually discontinued as cosmetic ingredients.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.162-170
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• 1996

Light cycle Oil(LCO) contains 2,6-dimethylnaphthalene (2,6-DMNA) which is used as the basic material for high performance engineering plastics and liquid crystal polymer. This study was experimentally investigated to concentrate a mixture of dimethylnaphthalene(DMNA) isomers in the LCO by extraction-distillation combination as a pretreatment for separation and purification of 2,6-DMNA in the LCO. Furthermore, concentration of a mixture of DMNA isomers in the LCO compared between distillation and extraction-distillation combination. The recovery of aromatics in the LCO was performed by batch cocurrent multistage extraction with dimethylsulfoxide and water mixture as solvent. The concentration of naphthalene group(carbon number 10-12) in the extracted mixture is higher than that in the LCO. The yield for naphthalene group increased with decreasing carbon number. The yield for a mixture of DMNA isomers obtained in 5 equilibrium extration runs was about 65%. the separation of individual components with extractedmixture was tested by batch distillation. Futhermore, for recovery of a mixture of DMNA isomers of high concentration, distillate containing DMNA was distilled. As a result, a mixture of DMNA isomers with high concentration such as 60wt% was recovered. The extraction-distillation combination was more effective than the distillation to concentration a mixture of DMNA isomer in the LCO.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.2
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• pp.175-184
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• 2019

The epidermal growth factor (EGF) has a intrinsic function of inducing growth and proliferation of cells through interacting with cell membrane receptors in human epidermis and dermis layer. These functions of EGF are used as a main ingredient for wound healing medicines and anti-aging cosmetics. As a cosmetic ingredient, the EGF has a problem in exhibiting its natural efficacy due to the lack of the ability to penetrate through the stratum corneum, which is known as the skin barrier. In this study, a recombinant human epidermal growth factor ($MTD_{151}-EGF$) fused with the macromolecule transduction domain $(MTD)_{151}$ with the skin penetration ability was developed to improve the skin penetration efficiency of the EGF. Expression of $MTD_{151}-EGF$ was performed in E. coli transformed with a vector encoding the $MTD_{151}-EGF$ gene and then purified. The purified $MTD_{151}-EGF$ was evaluated using cell proliferation assay, cytotoxicity test and skin penetration test by franz diffusion cell assay and artificial skin. Cell proliferation activity of $MTD_{151}-EGF$ purified to high purity of 99% or above was equivalent to the EGF or better, and cytotoxicity was not observed. In addition, the $MTD_{151}-EGF$ showed an excellent penetration efficiency compared to the EGF in the skin penetration test with EGF and $MTD_{151}-EGF$ labeled by FITC in an artificial skin penetration model. Based on the quantitative analysis of the penetrating substance using franz diffusion cell assay, the amount of penetration was about 16 times more than that of EGF. These results can be regarded as an effective alternative to improve the existing physical transdermal penetration method related to the use of various active ingredients for cosmetics.

• Resources Recycling
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• v.29 no.3
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• pp.61-74
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• 2020

This study was conducted to improve the recycling process of waste fluorescent lamp, and investigate the possibility of using the waste fluorescent lamp glass as a raw material for glass beads, the leaching method of rare earth from the waste phosphor powder, and the possibility of solvent extraction of rare earth from the rare earth leaching solution. The waste phosphor contained 28.9% yttrium oxide, 3.46% cerium oxide, 1.95% europium oxide, 1.76% terbium oxide, and 1.43% lanthanum oxide. As a result of the trial production of glass beads using waste fluorescent lamp glass, it was judged that the production yield and quality were excellent, so that waste fluorescent lamp glass could be used as a raw material for glass beads. The soda roasted waste phosphor was leached in water and thereby the aqueous solution was blown with CO₂ to drop the pH to about 7, Then, Al, Si and residual N₂CO₃ were dissolved, and NaAlCO₃(OH)₂ and SiO₂ were precipitated in the aqueous solution. In the solvent extraction of cyanex272-hydrochloric acid, cyanex272-sulfuric acid, D2EHPA-hydrochloric acid, D2EHPA-sulfuric acid, Ionquest290-hydrochloric acid, Ionquest290-sulfuric acid, p507-hydrochloric acid using xylene as a diluent, the extraction yield of Y, Eu, Ce, La, and Tb are close to 100%. However, in this conditions, the difference in extraction yield for each element, that is, selectivity is 16% or less.

• Geotechnical Engineering
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• v.14 no.6
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• pp.113-125
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• 1998

At the end of 1997 about 3 million tons of coal ash was produced as byproducts from the coal fired electrical power plants in Korea. Only about 27% of that byproducts was utilized as the admixtures of cement and concrete industry. But the large quantity of coal fired fly-ash has been used as the soil improvement materials in other countries. So the aim of this study is the estimation of the applicability of the coal fired fly-ash as microfine grouting materials by admixing the superfine particles which were separated from the coal fired fly-ash for the higher values. The 6 types of specimens were manufactured in the laboratory for the purpose of estimating the chemical and physical properties of cement and grouts. These specimens consisted of 2 specific surfaces of 6, 000 and 8, 000$cm^2$/g in Elaine method. And these specimens are devide into 3 ratios (30%, 50%, 70%) of fly-ash by weight. From the estimated properties of the coal fired fly-ash microflne cements and grouts, 50% fly-ash is the most suitable ratio for grouting materials. However, further study of durability is necessary for using fly-ash grouts practically at the field projects. The higher content of the unburned carbon of fly-ash increases the thinner layer of carbon on the surface of solution of grouts, and requires more quantity of surface active agent. As a results of this study, it is found that the microfine fly-ash is very useful as a good grouting material if 50% of fly-ash is added with the microfine portland cement. So, in the near future, if the coal fired fly-ash is able to be used as grouting material in Korea, the demand of fly-ash will increase rapidly.