• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.129-133
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• 2004

The active compound responsible fer the anti-oxidant activity in Chinese cabbage kimchi were isolated and identified. The dichloromethane fraction of Chinese cabbage kimchi with the greatest anti-oxidant activity was used. Silica gel column chromatography, Sephadex LH-20 column chromatography, TLC, and Sep-pak catridge were used for isolating the active compounds and IR, EI-MS, GC-MS, $^{1}H-NMR$, $^{13}C-NMR$ were used to identify the structure of the isolated compounds. 3-(4'-Hydroxyl-3',5'-dimethoxyphenyl)propionic acid of molecular weight 226, which had 3.4 times greater free radical scavenging activity than Vit. C and significantly greater anti-oxidant activity against LDL oxidation than the control, was obtained, This active principle may be beneficial in preventing hyperlipidemia and artherosclerosis in human.

• YAKHAK HOEJI
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• v.52 no.4
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• pp.241-251
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• 2008

In this study, isolation of antioxidative compounds was performed for development of anti-oxidizing agent. $CHCl_{3}$, $H_{2}O$, 30%, 60% MeOH, MeOH fractions were examined antioxidative activity by DPPH method, TBARS assay, and SOD like activity. It was revealed that 30%, 60% MeOH fractions had significant antioxidative activity. From 30%, 60% MeOH fraction, nine compounds were isolated and elucidated kaempferol $3-O-{\alpha}-L-rhamnopyranosyl$ $(1{\rightarrow}6)-{\beta}-D-glucopyranoside$ (1), quercetin $7-O-{\beta}-D-glucopyranoside$ (II), quercetin $3-O-{\alpha}-L-rhamnopyranosyl$ $(1{\rightarrow}6)$ ${\beta}-D-glucopyranoside(rutin)$ (III), 6-hydroxykaempferol $3-O-{\beta}-D-glucopyranoside$ (lV), kaempferol $3-O-{\beta}-D-glucopyranosyl$ $(1{\rightarrow}2)$ ${\beta}-D-glucopyranoside$ (V), kaempferol $3-O-{\beta}-D-glucopyranoside$ (VI), luteolin (VII), quercetin $3-O-{\beta}-D-glucopyranoside$ (VIII), apigenin $7-O-{\beta}-D-glucuronopyranoside$ (IX) through physicochemical data and spectroscopic methods (Negative FAB-MS, $^1H-NMR$, $^{13}C-NMR$). Entirely, all compounds had similar antioxidative activity, but more OH group had more antioxidative activity.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.11.2-11.2
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• 2011

Polymer based organic photovoltaics have attracted a great deal of attention due to the potential cost-effectiveness of light-weight and flexible solar cells. However, most BHJ polymer solar cells are not thermally stable as subsequent exposure to heat drives further development of the morphology towards a state of macrophase separation in the micrometer scale. Here we would like to show three different approaches for developing new electroactive polymers to improve the thermal stability of the BHJ solar cells, which is a critical problem for the commercialization of these solar cells. For one of the examples, we report a new series of functionalized polythiophene (PT-x) copolymers for use in solution processed organic photovoltaics (OPVs). PT-x copolymers were synthesized from two different monomers, where the ratio of the monomers was carefully controlled to achieve a UV photo-crosslinkable layer while leaving the ${\pi}-{\pi}$ stacking feature of conjugated polymers unchanged. The crosslinking stabilizes PT-x/PCBM blend morphology preventing the macro phase separation between two components, which lead to OPVs with remarkably enhanced thermal stability. The drastic improvement in thermal stabilities is further characterized by microscopy as well as grazing incidence X-ray scattering (GIXS). In the second part of talk, we will discuss the use of block copolymers as active materials for WOLEDs in which phosphorescent emitter isolation can be achieved. We have exploited the use of triarylamine (TPA) oxadiazole (OXA) diblock copolymers (TPA-b-OXA), which have been used as host materials due to their high triplet energy and charge-transport properties enabling a balance of holes and electrons. Organization of phosphorescent domains in TPA-b-OXA block copolymers is demonstrated to yield dual emission for white electroluminescence. Our approach minimizes energy transfer between two colored species by site isolation through morphology control, allowing higher loading concentration of red emitters with improved device performance. Furthermore, by varying the molecular weight of TPA-b-OXA and the ratio of blue to red emitters, we have investigated the effect of domain spacing on the electroluminescence spectrum and device performance.

• Korean Journal of Plant Resources
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• v.23 no.5
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• pp.393-398
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• 2010

Naturally occurring substances which strongly scavenge peroxynitrite(ONOO-) are evaluated to be beneficial for cardiovascular, diabetic, hypercholesterolemic and obese disease. To search for bioactive substances with peroxynitritescavenging activity from the young leaves of Heracleum moellendorffii(Umbelliferae) used for a mountainous vegetable, the experiment on peroxynitrite-scavenging assay, phytochemical isolation and HPLC analysis were undertaken. Activity-guided fractionation led to the separation of astragalin and hyperoside which were identified by physicochemical and spectroscopic data. The $IC_{50}$ values of astragalin and hyperoside were shown as $5.80{\pm}0.62$ and $0.560{\pm}0.26\;{\mu}M$, respectively, in the assay. The HPLC analysis led to the quantitative determination of astragalin and hyperoside by $30.0{\pm}0.01$ and $17.0{\pm}0.02\;mg/g$ dried weight, respectively.

• Journal of Internet Computing and Services
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• v.18 no.4
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• pp.89-97
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• 2017

The purpose of the present study was to estimate the effect of adolescents' depression on cell phone dependency and to identify mediating effects of parenting style and peer isolation. The study used data from the $6^{th}$ waves of 2015 KCYPS(Korean Children and Youth Panel Survey). Structural Equation Model(SEM) was conducted to examine the mediating effects of parenting style and peer isolation. The results showed that adolescents' depression had positive effects on cell phone dependency. In addition, the relationship between adolescents' depression and cell phone dependency was partially mediated by parenting style, not mediated by peer relationships. Based on these findings, further suggestions are provided to reduce adolescents' cell phone dependency by decreasing parent's over-involvement and improve adolescents' self control opportunities.

• KSBB Journal
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• v.14 no.6
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• pp.731-736
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• 1999

87 microbes were isolated from dyeing wastewater collected at Dongducheon and Banweol industrial complex. Five microbes showed excellent ability of color removal and were identified as Shewanella putrefaciens, Aeromonas salmonicida(3 different strains), and Pseudomonas vesicularis. Five identified strains had optimal pH and optimal temperature as 7.0 and 30$^{\circ}C$ for cultivation, and showed morphological characteristics of Gram negative, oxidase negative, rod shape, and non-motility, but their biochemical characteristics were distinguishable. Each single strain of five microbes were tested in the 500 mL flask to treat dyeing wastewater, and achieved about 35% color removal efficiency in average. When two strains were selected and applied to the treatment at same time, color removal efficiency was increased up to 65%. While three or more associations of each strain did not show the improvement of color removal. Inhibition effects by $Mn^{2+}\;and\;Fe^{3+}$ on the dye degradation were tested and resulted in no effect under 70 ppm concentration.

• Phonetics and Speech Sciences
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• v.5 no.2
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• pp.43-51
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• 2013

English native listeners have a tendency to treat strong syllables in a speech stream as the potential initial syllables of new words, since the majority of lexical words in English have a word-initial stress. The current study investigates whether Korean (L1) - English (L2) late bilinguals perceive strong syllables in English continuous speech as word onsets, as English native listeners do. In Experiment 1, word-spotting was slower when the word-initial syllable was strong, indicating that Korean listeners do not perceive strong syllables as word onsets. Experiment 2 was conducted in order to avoid any possibilities that the results of Experiment 1 may be due to the strong-initial targets themselves used in Experiment 1 being slower to recognize than the weak-initial targets. We employed the gating paradigm in Experiment 2, and measured the Isolation Point (IP, the point at which participants correctly identify a word without subsequently changing their minds) and the Recognition Point (RP, the point at which participants correctly identify the target with 85% or greater confidence) for the targets excised from the non-words in the two conditions of Experiment 1. Both the mean IPs and the mean RPs were significantly earlier for the strong-initial targets, which means that the results of Experiment 1 reflect the difficulty of segmentation when the initial syllable of words was strong. These results are consistent with Kim & Nam (2011), indicating that strong syllables are not perceived as word onsets for Korean listeners and interfere with lexical segmentation in English running speech.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.9
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• pp.1202-1209
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• 2009

Antimicrobial activity of UlGeum (Curcuma longa L.) was investigated. Methanol extract of dried UlGeum was fractionated to hexane, chloroform, ethyl acetate, butanol and water fraction. The antimicrobial activity of five crude fractions were examined using impregnated paper disk agar diffusion. Ethyl acetate fraction showed the highest inhibitory effect on the microorganisms such as B. subtilis, S. aureus, E. coli, L. monocytogenes and V. parahaemolyticus at 1,000 ${\mu}g$/disc. Ethyl acetate fraction was further fractionated by silica gel column and thin layer chromatography (TLC). The antimicrobial compound was isolated from their fractions and its chemical structure was identified as a 2,3-dihydrobenzofuran by GC-MS and $^1H$-NMR.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.281-284
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• 2007

Recently, we have developed p-i-n a-Si:H single junction thin film solar cells with RF (13.56MHz) plasma enhanced chemical vapor deposition (PECVD) system, and also successfully fabricated the mini modules ($>300cm^2$), using the laser patterning technique to form an integrated series connection. The efficiency of a mini module was 7.4% ($Area=305cm^2$, Isc=0.25A, Voc=14.74V, FF=62%). To fabricate large area modules, it is important to optimise the integrated series connection, without damaging the cell. We have newly installed the laser patterning equipment that consists of two different lasers, $SHG-YVO_4$ (${\lambda}=0.532{\mu}m$) and YAG (${\lambda}=1.064{\mu}m$). The mini-modules are formed through several scribed lines such as pattern-l (front TCO), pattern-2 (PV layers) and pattern-3 (BR/back contact). However, in the case of pattern-3, a high-energy part of laser shot damaged the textured surface of the front TCO, so that the resistance between the each cells decreases due to an incomplete isolation. In this study, the re-deposition of SnOx from the front TCO, Zn (BR layer) and Al (back contact) on the sidewalls of pattern-3 scribed lines was observed. Moreover, re-crystallization of a-Si:H layers due to thermal damage by laser patterning was evaluated. These cause an increase of a leakage current, result in a low efficiency of module. To optimize a-Si:H single junction thin film modules, a laser beam profile was changed, and its effect on isolation of scribed lines is discussed in this paper.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.25 no.3
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• pp.143-153
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• 1989

In conclusion, a high-Tc superconducting YBa sub(2) Cu sub(3) O sub(y) phase with zero resistance at about 90K was successfully prepared by nitrate solution method with densed micro structure. The result of the EDAX analysis on the isolated particles using the microscopic meissner effect showed that the particles were isolated at higher temperature due to the differences in O vacances rather than the differences in chemical compositions. The composition of the isolated particles were almost identical to the starting compositions on the samples prepared by the solid reaction and nitrate solution method but the Ba-rich composition were seen in the coprecipitated sample. The isolation process on Bi system was not successful due to the weak dimagnetism even though its high Tc above the liquid nitrogen temperature.