• Korean Journal of Plant Resources
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• v.26 no.3
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• pp.403-409
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• 2013

This study has assessed the anti-oxidative activities and cytotoxic effects of Lithospermum erythrorhizon ethanol extract and measured the effects of tyrosinase inhibition activities with a goal of estimating the usage of the medicinal plant as an ingredient of cosmetics. First, to perform a basic test on the extract, pH and UV-spectrum were measured. According to the measurement, the extract had control functions at pH 5.5, and maximum absorbance occurred at 530nm. In particular, DPPH (1-1-diphenyl-2-picryl-hydrazyl)-inhibiting activity (IC50) and polyphenol content were 149.81 ${\mu}g/mL$ and $51.28{\pm}2.52$ mg/mL respectively. In addition, as extract concentration increased, tyrosinase inhibition activities improved as well. In raw 264.7 cell-based MTT assay, cell survival rates were 98% at 1000 ppm and 153% at 100 ppm. Therefore, it's been confirmed that there is almost no cytotoxin. According to the test results above, it appears that the Lithospermum erythrorhizon ethanol extract would be effective in anti-oxidation and application as a cosmetic ingredient.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.439-442
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• 2005

An airborne radar performance can be sensitive to the variation of the Doppler center frequency and the spectral spread of the ground clutter return due to the radar platform moving and aspect angle of the scanning beam to the target. In this paper, for the performance test of the airborne pulsed Doppler radar system developed, the high-speed radar data acquisition system is implemented for acquiring the raw radar signal in real-time. Based on the various test scenarios from airborne-platform to the moving platform, the various radar target and clutter signals are collected and their spectrum is analyzed for the verification of the radar performance in the real-time flight test environments.

• 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 Environmental Science International
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• v.8 no.3
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• pp.363-369
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• 1999

This study aimed to elucidate the relationship between theoretical parameters affecting the coagulation process and the real coagulation phenomenon applied to the dye wastewater. Emphasis was placed on the effective removal of the suspend particulates. Parameters studied in this study are pH, coagulant concentration and surface potential. Optimal dosages of coagulants by the measurement of the zeta potential at lower then $25^{\circ}C$ are 5\times$10^P-3}$ M of $FeCl_3 and 1.4\times10^{-6}M of Fe_2(SO_4)_3$. The results were well agreeded with the separate Jar-test results. Emphasis was also placed on the relationship between water quality and the content of SS. It was found that the COD and DOC were reduced to 65% and 85%, respectively. The turbidity at the above condition was reduced from 300 NTU to 0~1 NTU. Efforts were made to clarify the behavior of the suspend solid as affecting the water quality. 12,000~13,000 particles/10mL in $1~50\mu$m size range particulates in the raw wastewater were reduced to 300 particle/10mL in the same range after treatment. This research has proposed the methodology to find out the optimal condition of coagulation for small scale wastewater treatment plant or chemical coagulation process.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.621-626
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• 2001

Microcellular foaming process was developed at MIT in 1980's to save a quantity of raw materials and improve mechanical properties. There are many process variables in appling microcellular foaming process to the conventional injection molding process. Of all process variables, part dimension control and shrinkage are the most influential on the post molded dimension. The post molding dimensional change of thermoplastic resins is important to tool designers for predicting the specific difference of molded part vs. actual mold cavity. Generally, articles injection molded are smaller in size than the cavity; hence, the term shrinkage factor is used to define the allowance a designer specifies. It is important to consider the factors that influence molded part dimension. According to ASTM Designation: D 955, shrinkage from mold dimensions of molded plastics was measured. In injection molding, the difference between the dimensions of the mold and of the molded article produced therein from a given material may vary according to the design and operation of the mold. In this paper, shrinkage data of molded plastic parts was obtained. It can be an important information for designing optimum mold system in a microcellular foaming injection molding process.

• Korean Journal of Pharmacognosy
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• v.42 no.4
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• pp.323-328
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• 2011

We investigated antioxidative activity, tyrosinase inhibitory activity, and melanin production inhibitory activity of the methanol extract of Paeoniae Radix and its fractions. The total polyphenol content of the extract was 73.45 mg/g, and content of the ethyl acetate fraction was 514.50 mg/g as the highest content of fractions. In DPPH radical scavenging ability, $SC_{50}$ values of the ethyl acetate was 3.86 ${\mu}g/ml$ as a result of greater activity in the positive control (ascorbic acid). Moreover, tyrosinase inhibitory activity of the ethyl acetate fraction showed higher activity than arbutin used as a positive control. In the cytotoxicity measurement by MTT assay, the extract and fractions were exhibited cell viabilities of 76.96~157.26% against Raw 264.7 and B16F10 cell in concentration of 10~100 ${\mu}g/ml$. In nontoxic concentration range, the ethyl acetate fraction showed strong melanin production inhibitory effect in ${\alpha}$-melanocyte stimulating hormone (${\alpha}$-MSH)-stimulated B16F10 cell. As a result, the ethyl acetate fraction of the methanol extract from Paeoniae Radix could be applicable to functional materials for skin-whitening agents.

• Korean Journal of Medicinal Crop Science
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• v.19 no.5
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• pp.362-367
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• 2011

The study was conducted to investigate functional materials as skin whitening and anti-inflammatory agent from Taraxacum officinale and Taraxacum coreanum. The total polyphenol and flavonoid content in the ethanol extract of Taraxacum officinale were found to be 64.07mg/g and 32.46mg/g, respectively. In tyrosinase inhibitory activity, the hot water extract of Taraxacum coreanum was higher than the other extracts. However, in nitric oxide (NO) scavenging ability, the ethanol extract of Taraxacum coreanum was higher than the other extracts. the ethanol extract of Taraxacum coreanum showed strong NO production inhibitory effect in lipopolysaccharide (LPS)-stimulated Raw 264.7 cell. In the cell viability measurement by MTT assay and the lactate dehydrogenase (LDH) assay against L929 cell, the extracts were exhibited fine cell viabilities and normal LDH release levels as nontoxic result in sample concentration of $250{\sim}1000{\mu}g/m{\ell}$. As a result, the ethanol extract and the hot water extract of Taraxacum coreanum could be applicable to functional materials for anti-inflammatory and skin whitening related fields, respectively.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.3
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• pp.28-36
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• 2010

Today We have three full series of the annals of Joseon Dynasty. Taebaeksan volume which is one of them shows comparatively good maintenance but Taebaeksan volume also decomposed in patches. The size of cover and inner paper were increased in late Joseon Dynasty, but the weight, thickness and basis weight bears no relation to each other. The oxidation index of paper in annals of pre-periods of King Sunjo shows very high value. After the annals of King Sunjo, the oxidation index of paper is very similar to today's Hanji. L.a.b values of inner paper in the Taebaeksan volume are similar generally. The average length of fiber using image analysis soft ware is 8.08~9.92 mm, that like immediate value of measurement. The air fraction of fiber's range is 1.20~2.12%. It lower than today's Hanji. After considering the factors of the length of fiber, air fraction and FE-SEM, we reached that no difference between raw material of inner paper in the Taebaeksan volume.

• Journal of the Korean Society for Heat Treatment
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• v.33 no.5
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• pp.232-238
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• 2020

Heating experiments using the 7075 aluminum alloy in the state of billet and extrudate have been performed to investigate the pertinent ranges of working temperatures and holding times for the application to the various automobile parts. The 7075 specimens from raw billet of 152 mm in diameter and 400 mm in length prior to extrusion were used for heating with a holding time of 10 minutes at temperatures between 380℃ and 550℃. Then, an extrusion process using the billet has been fulfilled at 380℃ with extrusion speed of 0.8 mm/min to get an plate-type extrudate of 75 mm in width and 4.2 mm in thickness. The samples from the extrudate were subjected to heating experiments at temperatures between 380℃ and 440℃ with holding times such as 10 min, 30 min, 60 min and 120 min at each heating temperature. The microstructures were investigated on the optical and EBSD micrographs. The hardness measurement and the tensile test have been performed to investigate the effect of the heat treatment on the mechanical property. The results showed for the 7075 extrusion process that the safe heating of billet can be performed below 450℃ and the extrusion can be done safely up to 400℃.

• Journal of the Korean Applied Science and Technology
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• v.26 no.4
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• pp.428-433
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• 2009

Cellulose triacetate (CTA) was prepared from cotton linter and pulps which contain various contents of $\alpha$-cellulose. CTA which contains 2.8 of degree of substitution (DS) and 222 of degree of polymerization (DP) was obtained from V-81 pulp under the heterogeneous system. The DS was measured by the titration method, and the DP was obtained by measurement of viscosity. FT-IR spectometer (FT-IR 6300, JASCO) was used to analyze the chemical structure of raw materials and cellulose triacetate, and X-ray diffractometer (X-pert MPD PW3040, Philips) was used to confirm the crystal structure and to calculate the relative crystallinity index (RCI). As $\alpha$-cellulose content in pulp increased, the acetylation yield increased. Besides with a kind of pulp, it contains insoluble residue which was mainly formed due to the formation of glucomannan triacetate and xylan diacetate during the esterification.