• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1807-1818
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• 2005

New PPV based conjugated polymers, containing terphenyl units, were prepared as the electroluminescent (EL) layer in light-emitting diodes (LEDs). The prepared polymers, poly[2,5-bis(4-(2-etylhexyloxy)phenyl)-1,4-phenylenevinylene] (BEHP-PPV), poly[2-(2-ethylhexyloxy)-5-(4-(4-(2-etylhexyloxy)phenyl)phenyl)-1,4-phenylenevinylene] (EEPP-PPV) and poly[2-(2-ethylhexyloxy)-5-(9,9-bis(2-etylhexyl)fluorenyl)-1,4 phenylenevinylene] (EHF-PPV), were soluble in common organic solvents and used as the EL layer in double layer light-emitting diodes (LEDs) (ITO/PEDOT/polymer/Al). The polymers were prepared by the Gilch reaction. The number-average molecular weight $(M_n)$, weight-average molecular weight $(M_w)$, and the polydispersities (PDI) of these polymers were in the range of 9000-58000, 27000-231000, 2.9-3.9, respectively. These polymers have quite good thermal stability with decomposition starting above 320-350. The polymers show photoluminescence (PL) with maximum peaks at around 526-562 nm (exciting wavelength, 410 nm) and blue EL with maximum peaks at around $\lambda_{max}$ = 526-552 nm. The current-voltageluminance (I-V-L) characteristics of polymers show turn-on voltages of 5 V. Even though both of EEPP-PPV and BEHP-PPV have the same terphenyl group in the repeating unit, EEPP-PPV with directly substituted alkoxy group in the back bone has longer effective conjugation length than BEHP-PPV, and exhibits red shift in the PL spectra. Both of EEPP-PPV and EHF-PPV have ter-phenyl units and directly substituted alkoxy group in back bone. EHF-PPV with fluorenyl unit attached to the PPV backbone has shorter effective conjugation length than EEPP-PPV with biphenyl unit, and exhibits blue shift in the PL spectra.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.260-270
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• 2017

Zirconia has white color and physical, chemical stability, also using in high temperature materials and various industrial structural ceramics such as heat insulating materials and refractories due to their low thermal conductivity, excellent strength, toughness, and corrosion resistance. If hydrophobically modified zirconia is introduced into a hydrophobic acrylate coating solution, the hardness, chemical, electrical, and optical properties will be improved due to the better dispersibility of inorganic particle in organic coating media. Thus, we introduced $-CH_3$ group through silylation reaction using either trimethylchlorosilane(TMCS) or hexamethyldisilazane(HMDZ) on zirconia surface. The $Si-CH_3$ peaks derived from TMCS and HMDZ on hydrophobically modified zirconia surface was confirmed by FT-IR ATR spectroscopy, and introduction of silicon was confirmed by FE-SEM/EDS and ICP-AES. In addition, the sedimentation rate result in acrylate monomer of the modified zirconia showed the improved dispersibility. Comparison of the sizes of a pristine and the modified zirconia particles, which were clearly measured not by the normal microscope but by particle size analysis, provided a pulverizing was occurred by physical force during the silylation process. From the BET analysis data, the specific surface area of zirconia was approximately $18m^2/g$ and did not significantly change during modification process.

• Journal of Life Science
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• v.28 no.7
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• pp.802-810
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• 2018

Aging is accompanied by changes in the body, such as graying hair, wrinkles, and black spots composed of lipid peroxides and proteins. Melanin is a polymer substance produced by an oxidation polymerization reaction from tyrosine, and it determines the color of hair and skin. It has been reported that melanin is synthesized by melanocyte, and its excessive production by reactive oxygen species is associated with aging. The purpose of this study was to determine the direct effects of Musa paradisiaca peel ethanolic extract (MPEE) on antioxidative activity and melanin synthesis. It was observed that the antioxidant activity of MPEE was similar to that of vitamin C, a positive control, in both DPPH radical scavenging assay and reducing power assay. In order to examine cytotoxicity prior to cell experimentation, 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed for B16F1 cells. MPEE was not cytotoxic at $32{\mu}g/ml$ or less. In addition, MPEE increased melanin synthesis in live cells in addition to tyrosinase activity and melanin synthesis in dihydroxyphenylalanine (DOPA)-oxidation assay in vitro. Moreover, MPEE increased melanin synthesis in cells aged by pretreatment with $H_2O_2$. The expression levels of tyrosinase-related protein (TRP)-1, TRP-2, and superoxide dismutase (SOD)-2 by western blot analysis were increased in the presence of MPEE. These results suggest that MPEE could promote the melanin synthesis as an antioxidative substance.

• Microbiology and Biotechnology Letters
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• v.37 no.2
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• pp.110-117
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• 2009

To characterize plant root-associated bacteria in wild plant family Solanaceae, Solanum nigrum L. plants were collected in Dokdo island. Forty four strains of nitrogen-fixing or spore-forming bacteria were isolated from rhizosphere of Solanum nigrum L. plants. Among these, 19 strains were able to produce auxin. Thirteen strains of these produced siderophore as determined by color reaction on CAS-blue plate, 8 strains were able to solubilize phosphate. The 16S rDNA genes of the isolated bacteria were amplified and sequenced. Model plants, pepper and tobacco, were established in order to evaluate the bacterial capacities eliciting growth promotion and induced systemic resistance. The plants treated with strain KUDC1009 were more resistant and capable of growth-promotion than control plants when challenged by either Xanthomonas axonopodis pv. vesicatoria or Erwinia carotovora sub. carotovora strain SCC1. Rhizobacteria isolated from Dokdo island can promote growth of wild type Solanum nigrum L. under much environmental stresses.

• Applied Biological Chemistry
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• v.48 no.2
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• pp.109-114
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• 2005

A bacterium capable of emulsifying hydrocarbon, n-hexadecane, and decreasing surface tension of the culture media using oil collapsing method was isolated. The bacterium was partially identified as Bacillus sp. and named BJS-51. n-Hexadecane was the most effective carbon source for production of biosurfactant. Surface tension was decreased from 76 dyne/cm to 31 dyne/cm and CMD (critical micelle dilution) had the highest value of 5.7 at 3% n-hexadecane. Ammonium phosphate was the most effective nitrogen source, when C/N ratio was 60, surface tension and CMD were 29 dyne/cm and 9.2, respectively. Optimum pH and temperature were 7.2 and $30^{\circ}C$, respectively. Produced biosurfactant was extracted and purified using organic solvent extraction method and preparative HPLC systems. After analysis by various color reaction, this biosurfactant was identified as lipopolysaccharide. Surface tension and CMC (critical micelle concentration) of purified biosurfactant were 27 dyne/cm and 0.08 g/l, repectively. CMD was 9.2, so the yield of biosurfactant was about 0.74 g/l at the optimal conditions. The biosurfactant was very stable at wide range of $pH\;2{\sim}12$ with surface tension $29{\sim}31\;dyne/cm$ and showed $29{\sim}30\;dyne/cm$ of surface tension after heat treatment at $100^{\circ}C$ for 60 min.

• Journal of the Korean Ceramic Society
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• v.41 no.12 s.271
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• pp.921-928
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• 2004

Calcium phosphate powders have been prepared by using $Ca(OH)_2\;and\;H_{3}PO_4$ solution under various conditions such as pH, calcination temperature, and reaction time. ${\beta}-TCP({\beta}-tricalcium phosphate)$and HAp(hydroxyapatite) were synthesized at pH=5.21 and pH > 7.62, respectively. From XRD results, $Ca(OH)_2\;and\;H_{3}PO_4$ solution reacted quickly to form HAp, which was structurally stable up to 16h. Calcination temperature having good crystallinity is revealed to be at $1200^{\circ}C$. SEM analysis showed that ${\beta}-TCP$ and HAp with needle type were synthesized at pH 5.21 and pH 7.62, respectively. However, at pH 9.16, tiny and homogeneous HAp having sphere was prepared and rearranged to show needle morphology. HAp synthesized at pH 9.16 was utilized as bonechina body and calcined. The sample was analyzed its crystallinity, water absorbtion, color, and shape to check physical properties.

• Journal of Fashion Business
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• v.15 no.1
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• pp.185-204
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• 2011

The purpose of this study is to take into consideration the formative and aesthetic characteristics of wedding dresses that existed during the periods of Neo-Classicism and Romanticism which appeared as a reaction toward Neo-Classicism. The method of the research was mainly focused on precedent research data and general references. Furthermore the data on wedding dresses was mainly collected from British, French, and American library and museum web sites. The result of the research is the following. The Neo-Classicism art, which appeared along with the enlightenment in the beginning of the 19th century, pursues beauty based on associations and imitations of ancient Greek and Roman arts. In addition to aforementioned pursuits, the Neo-Classicism art also pursued universal beauty and social usefulness through law and order. This aesthetic value was also applied to the wedding dresses, so classical beauty, natural beauty and universal beauty were expressed as follows: corsets of the previous era were removed from general clothing and Empire style that imitated natural Greek style became predominant. Also, muslin replaced high quality clothes which were used as the main materials of the dressing during the previous era. Empire style's wedding dress became popular and simple colors and styles of the wedding dress expressed the beauty of the human body and emphasized civility at the same time. Romanticism art and costumes opposed rationalism and pursued sentimentalism. Moreover, it pursued diversity, exotic tastes and accepted diverse reactionism unlike Neo-Classicism's simplification and standardization. These aesthetic characteristic were applied to the wedding dress of this period; wedding dress of romanticism pursued feminine and elegant beauty with "X" silhouettes and various decorations, like general costumes. And they were decorated with a variety of excessive accessories, details and trimmings to express romantic sentimentalism. Exotic tastes which included Chinese, Egyptian, Indian influence and other diverse tastes were expressed through hair style, accessories and patterns of shawl. However, the white color in the wedding dress revealed purity and sanctity which cannot be found from general costumes regardless of whether the dress expressed Neo-classicism or Romanticism. As a formal dress worn during wedding ceremonies, the wedding dresses of the royalty revealed dignity and authority and significantly influenced later wedding dress designs.

• Korean journal of food and cookery science
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• v.18 no.4
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• pp.413-425
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• 2002

Quality characteristics of white bread added with lotus root powder(3, 6%) were investigated. Moisture content of white bread added with lotus root powder were higher than control. As the amount of added lotus root powder increased, the lightness, redness and yellowness of bread crust as well as the volume of the bread decreased, but the redness and yellowness of the crumb increased slightly. The content of free amino acids increased by the addition of lotus root powder and the major ones were L-glutamic acid, L-alanine, L-valine and threonine. The major flavor components were 2-methyl butanal and 3-methyl butanal, which were formed by the amino-carbonyl reaction in baking bread at high temperature. Aldehyde flavor components such as 2-ethylfuran, 2-butanedione and 3-butanedione were formed by yeast fermentation. Ethyl acetate and vinyl acetate also influenced the flavor of the bread. The addition of lotus root powder increased the hardness and fracturability, and decreased the gumminess, chewiness and cohesivenes of the bread. Sensory evaluation of white bread indicated that the addition of 3%, 6% lotus root bread enhanced the grain formation, color, mouth feeling, appearance, hardness, moistness, flavor and overall acceptability. Overall, the addition of 6% lotus root powder showed the best performance in the nutritional and functional aspects of the bread.

• Korean Journal of Food Science and Technology
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• v.19 no.3
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• pp.195-199
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• 1987

Changes in quality characteristics of boiled-dried anchovy during storage under different packaging conditions for 6 months were studied. For the packaging trials, kraft paper (KP), kraft paper laminated with 0.03 mm polyethylene film (KP/PE) and 0.1 mm polyethylene film with nitrogen gas substitution ($N_2$ gas) were employed. In case of KP, the reaction of thiobarbituric acid, browning rate of lipid oxidation and Hunter color values of L, a and b were remarkably higher than those packaged in KP/PE or $N_2$ gas. Judging from organoleptic evaluation boiled-dried anchovy could be preserved in acceptable condition for 6 months at $5^{\circ}C$in all packaging cases and, at room temperature, 3 months in KP and 4 months in KP/PE or $N_2$ gas. From the standpoint of quality stability by packaging methods, it was concluded as good in sequence as $N_2$, gas, KP/PE and KP. The results suggest that the quality of boiled-dried anchovy be well preserved by packaging with inert gas ($N_2$ gas) or impermeable material to vapors and oxygens.

• Journal of the Mineralogical Society of Korea
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• v.28 no.2
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• pp.135-145
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• 2015

In order to predict the deterioration of stone monument due to acid fog, an artificial fog test using pH4.0 and pH5.6 was applied to the Gyeongju Namsan granite, decite and marble. After the test had weathered Gyeongju Namsan granite a larger weight reduction due to acid fog than fresh one. Decite has shown the most significant changes among the tested rocks with about 0.005 % of weight reduction. Decite and weathered granite will have considerable weight reduction due to acid rain than the acid fog, whereas the marble was expected to show a weight reduction regardless of the phase of water. The porosity and water absorption rate of weathered granite had significantly increased. This result means that the weathered rock is predicted to be more susceptible to acid fog than the fresh rock. The absorption rate of the marble after the test had shown approximately 50 % increase. The color of the samples had slightly changed towards yellow, such tendency was greater shown in weathered rocks. The marble reacted with acid fog had an increased whiteness. A large amount of cation in the samples is caused mainly by the dissociation of minerals through the reaction with acid fog.