• Korean Journal of Pharmacognosy
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• v.51 no.4
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• pp.302-309
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• 2020

The objective of this study was to optimize the condition for induction and proliferation of callus from Rhus chinensis Mill. and investigate the skin-brightening effect of Rhus chinensis callus (RCC). It was confirmed that the most proper plant growth regulator (PGR) for callus induction is 1.0 mg/L of 2,4-dichlorophenoxyacetic acid (2,4-D). The most optimal condition of PGR, medium and additives for callus proliferation were 2,4-D (1.0 mg/L), MS medium and citric acid, respectively. Inhibitory activities of tyrosinase were higher at 50 and 100 ㎍/mL of RCC extracts (41.86 and 75.56%, respectively) than arbutin (27.32%). As the results of measuring melanin inhibition in B16F1 melanocyte and B16F10 melanoma cell, RCC extracts increased its inhibitory activities concentration-dependently, and were found to have higher whitening effect than arbutin at a concentration of 100 ㎍/mL. Therefore, it is suggested that RCC can be used as an effective material for skin-brightening cosmetics.

• Korean Journal of Plant Tissue Culture
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• v.27 no.4
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• pp.309-315
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• 2000

Panax ginseng is an important medicinal plant that has been used worldwide for geriatric, tonic, stomachic, and aphrodisiac treatments. Ginsenosides contained in the ginseng root are the main substances having active functions for human body. The price of ginseng is very expensive due to a complex process of cultivation, and the yield of ginseng is limited, which cannot meet the demand of the increasing market. Researchers have applied plant biotechnology to solve the problems but there are still things to be determined towards ginsenoside production by large-scale adventitious root culture. In this experiment, 5 to 20 liter bioreactors were employed to determine optimal conditions for adventitious root culture and ginsenoside production of Panax gineng. Callus was induced from the ginseng root on MS agar medium containing 1.0 mg. $L^{-1}$ 2,4-D and 0.1 mg. $L^{-1}$ kinetin. Then the callus was cultured on MS agar medium supplemented with 2.0 mg. $L^{-1}$ IBA, 0.1 mg. $L^{-1}$ kinetin, and 30 g. $L^{-1}$ to induce adventitious roots. The maximum root growth and ginsenoside production were obtained in 1/2 MS medium. 2.0 mg. $L^{-1}$ naphthalene acetic acid resulted in greater root growth than 2.0 mg $L^{-1}$ indole-3-butyric acid. Ginsenoside content increased with 2.0 mg. $L^{-1}$ benzyl adenin or kinetin. High concentrations of benzyl adenin (above 3.0 mg. $L^{-1}$ ) decreased the adventitious root growth and ginsenoside productivity. N $H_{4}$$^{+}$ inhibited the ginsenoside accumulation, while high concentrations of $K^{+}$, $Mg_{2}$$^{+}$, and $Ca_{2}$$^{+}$ increased it. N $H_{4}$$^{+}$ at 0.5 and 1.0 times of the normal amount in 3/4 SH medium resulted in the greatest biomass increase, but the highest ginsenoside productivity was obtained when N $O_{3}$$^{-}$ was used as the sole nitrogen source in the medium. Most microelements at high concentrations in the medium inhibited the root growth, but high concentrations of MnS $O_4$enhanced the root growth. Root dry weight increased with increasing sucrose concentrations up to 50 g. $L^{-1}$ , but decreased from 70 g $L^{-1}$ Ginsenoside productivity was maximized at the range of 20 to 30 g. $L^{-1}$ sucrose. In the experiment on bioreactor types, cone and balloon types were determined to be favorable for both adventitious root growth and ginsenoside production. Jasmonic acid was effective for increasing ginsenoside contents and Rb group ginsenosides mainly increased. These results could be employed in commercial scale bioreactor cultures of Panax ginseng.x ginseng.

• Korean Journal of Child Studies
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• v.26 no.5
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• pp.297-309
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• 2005

This study investigated the relationship between young children's narrative representation of mother and their self-concept. Subjects were 120 children of 5 years 01d(60 boys and 60 girls) at three nursery centers located in Daejon city. The children's narrative representation of their mother was examined using the tool of Ryu & Lee(200l) based upon MSSB made by Bretherton et al(1990). And the children's self-concept was examined using the tool of Lim(1995) based upon 'I feel${\cdots}$Me feel' made by Bently & Yeatts(1974). The data were analysed by frequency, two independent t-test and Pearson's correlation with SPSS program. The young children's narrative representation of mother was positive. And there were significant correlations between the young children's narrative representations of mothers and their self-concept.

• English Language & Literature Teaching
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• v.17 no.3
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• pp.309-326
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• 2011

This study examines the relationship between second language use outside of class and oral proficiency development. It first identifies out-of-class activities of international graduate students in the U.S. and the average time spent speaking English in those out-of-class activities. Interviews and student self-measurements of time spent speaking English each day were used to investigate the types and quantities of out-of-class activities. In addition, two sets of student oral proficiency test scores were collected. Correlation analysis is used to find out the relationship of the variables between the most salient out-of-class activities and oral proficiency gains. The findings indicate that second language use outside of class is important for international graduate students to improve their oral proficiency. This is especially true with regularized interaction such as talking at work and the average time spent speaking in English a day outside of class. This study suggests that learners of English in an ESL environment should be encouraged to take part in out-of-class activities in addition to English use in the classroom in order for them to improve their oral proficiency.

• English Language & Literature Teaching
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• v.13 no.1
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• pp.27-46
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• 2007

Teachers can maximize students' L2 learning by knowing preferred learning styles. This paper presents the results of a survey that asked 309 English learners to identify their perceptual learning style preferences. It further compared students' favored learning styles in terms of their gender and major field of study and explored a possible link between learning styles and English achievement. Collected data using Reid's (1995) questionnaire were analyzed by descriptive statistics, MANOVA, ANOVA, correlations, multiple regressions including squared partial correlations, and Cronbach's alpha. The results indicated that Korean students favored English learning in group regardless of gender, while their preferred mode of learning was significantly different in regard to their major field of study. Certain learning styles might be profitable for English achievement. Multiple regression analyses revealed that individual mode of learning was the best predictor of students' English achievement. It furthermore showed significant relationships between visual and individual styles of learning and English performance. The findings of the study reflected students' English learning context in which English native-speaking teachers frequently used communicative pair and small group activities for speaking practices that were consonant with students' learning styles.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.309-312
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• 2004

Aspergillus sojae B-l0 was immobilized and used to treat model dye compounds. The model wastewater, containing 10 ppm of azo dyes such as Amaranth, Sudan III, and Congo Red, was treated with cells attached to a rotating disc contactor (RDC). Amaranth was decolorized more easily than were Sudan III and Congo Red. Decolorization of Amaranth began within a day, and the dye was completely decolorized within 5 days of incubation. Both Sudan III and Congo Red were almost completely decolorized after 5 days of incubation. Semicontinuous decolorization of azo by reusing attached mycelia resulted in almost complete decolorization in 20 days. This experiment indicated that decolorization was successfully conducted by removing azo dyes with Aspergillus sojae B-10.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.309-313
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• 1997

(Ba$_{x}$Sr$_{l-x}$)TiO$_3$(BST) thin fi1ms with various Ba/Sr ratios were deposited on Pt(80nm)/SiO$_2$(100nm)/Si by RF magnetron sputtering. BST thin films which have x=0.6, 0.5, 0.4 were studied dielectric properties with temperature variation. The frequency was used from 100Hz to 1MHz for measuring dielectric constant. The measurement conditions of dielectric constant with Temperature Variation were 1KHz and 2$0^{\circ}C$. As a result, the dielectric constant of BST thin film was about 425 and loss factor was 0.013. Also, with increasing Temperature, the dielectric constants of BST thin films were gradually decreased.sed.

• Bulletin of the Korean Chemical Society
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• v.26 no.9
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• pp.1415-1420
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• 2005

The spectral interferences of OH from aqueous solvents in ICP-AES have been studied and eliminated using a cryogenic argon trap. The prominent lines of Bi I 306.772 nm, Al I 309.271 nm, and V II 310.230 nm, which are very seriously overlapped with the OH band, were examined. With an extended torch and high tangential flow of 20 L/min, water vapor from air entrainment was prevented. The combination of a condenser and argon cryogenic trap was able to eliminated most of water vapor carried by the argon sample gas. Removal of OH spectral interference could extend the linearity of the calibration curve 5-10 times on the lower concentration for ICP-AES. Interference Equivalent Concentration (IEC) has been reduced to 5.6, 5.9, and 12.4 times for Bi, Al and V, respectively.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.304-309
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• 2001

Natural frequencies are studied for dynamic analysis of plate girder bridges which are made up about 34% in the existing railway bridges in Korea. In this study, standard plate girder bridges designed by L-22, a standard load type of the railway specification in Korea, are modeled for finite element method analysis. SAP2000n, a commercial finite element method analysis tool, is used for structural analyses and evaluations. Span lengths of Plate girders have 7 types : 6m, 9m, 12m, 15m, 22m, 24m, and 30m. Natural frequencies are considered in mass rations and span lengths and they are compared with a recommendation of UIC 776-1R for alterations, from now on, in train conditions of operation. For changes of natural frequencies in plate girders by damages of structures, Parameter studies are accomplished.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.306-309
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• 2003

The natural soil containing organic matter and ferrous is used in the Electrokinetic-Flushing Remediation(EFR) tests. A series of tests are carried out through controlling the concentration of acetic acid in the EFR cell. The test results showed that the electrical potential in X/L=0.9 is increased with the increasing of the concentration, and pH in the sample is the similar at all of the region because of the buffer capacity of natural soil. Finally, the efficiency of EFR is enhanced at acetic acid of 1mM. But it may not be not strongly affected by the concentration of acetic acid.