• KIEAE Journal
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• v.1 no.1
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• pp.35-43
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• 2001

The VOC, which were detected from the newly built house, exist as a certain number of types according to the characteristics of the change of VOC concentration indoors. In this paper, we aim to divide the VOC into types so that those with similar characteristics of the transition of their concentration are in the same group and select the representative compound according to each classified type, and to verify these processes statistically in order to verify and propose new method creating the representing index of the VOC concentration in indoor which is used in evaluation of the degree of air pollution. As a result, the characteristic of the change of VOC concentration in the indoor can be divided into three types. Type1; the group in which the concentration is relatively high right after the completion of the house, and then decreases rapidly. Type2; the group in which the concentration is relatively low right after the completion of the house, and then although it shows the tendency of increasing and decreasing repeatedly, it decreases overall. Type3 is the group, which show only one peak at a certain time during the measuring period. As the method like this was verified to have the statistical significance, the Ethylbenzene was selected as the representative compound of type1, and Styrene was selected as that of type2. Moreover, if considering transition of the VOC from the point of similarity, the research method of making the classification and the selection of the representative compound in this study are said to be significant method.

• Journal of the Korean Home Economics Association
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• v.44 no.1 s.215
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• pp.101-113
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• 2006

The purpose of this study was to investigate and compare the characteristics of the motifs on cultural goods in In-Sa-Dong Street, Seoul, with those in Art Street, City Hall, Kwang-ju. For this study, 607 cultural goods were collected from the two cities: 265 in Seoul and 342 in Kwang-ju. Total cultural goods were classified by accessories, decoration pieces, stationery and ceramics and were studied by repetition patterns, motifs types, representative techniques, and representative types. The results were as follows. First, for repetition patterns of motifs, there were 219 simple repetition patterns in Seoul, and 289 in Kwang-ju, and 46 compound repetition patterns in Seoul, and 53 in Kwang-ju. The ratio of simple repetition pattern was higher than that of compound repetition pattern in both cities. Second, for motif types, floral, animal, letter, and graphic motifs were used far more frequently than any other motif types. Third, for representative techniques, embroidery was far more frequently used than any other representative techniques. Metallic crafts, chil-bo and paper techniques were also favored. Fourth, for representative types, realistic types were more common than abstract types.

• YAKHAK HOEJI
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• v.57 no.4
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• pp.272-281
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• 2013

In this study, we developed and validated the HPLC method using the isolated components from Erycibae caulis. Their structures were elucidated by spectroscopic methods including UV, $^1H$-NMR, $^{13}C$-NMR, FAB-Mass and ESI-Mass as Compound 1 (crypto-chlorogenic acid), Compound 2 (scopolin), Compound 3 (neochlorogenic acid) and Compound 4 (3,4-di-O-caffeoylquinic acid). Major three compounds and scopoletin were decided as representative components of Erycibae caulis. We established HPLC analytical method by using the representative components and 20 commercial samples which were collected considering to various cultivated area. The HPLC fingerprinting was successfully achieved with an AKZO NOBEL Kromasil 100-5C18 column. The mobile phase consisted of 0.5% acetic acid in water (A) and methanol (B) using gradient method of 85(A) to 50(A) for 35min. The fingerprints of chromatograms were recorded at an optimized wavelength of 330 nm. This developed analytical method was validated with specificity, selectivity, accuracy and precision. And it is suggested that scopolin, scopoletin, neochlorogenic acid, 3,4-di-O-caffeoylquinic acid were more than 0.162%, 0.133%, 0.057%, 0.044%, respectively. In addition, principal component analysis (PCA) was performed on the analytical data of 20 different Erycibae caulis samples in order to classify samples collected from different regions. We hope that this assay can be readily utilized as quality control method for Erycibae caulis.

• Journal of the Korean Chemical Society
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• v.52 no.4
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• pp.394-403
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• 2008

• Composites Research
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• v.34 no.1
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• pp.70-75
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• 2021

This paper presents a novel algorithm to reconstruct meso-scale representative volume elements (RVE), referring to experimentally observed features of Sheet Molding Compound (SMC) composites. Predicting anisotropic mechanical properties of SMC composites is challenging in the multiscale virtual test using finite element (FE) models. To this end, an SMC RVE modeler consisting of a series of image processing techniques, the novel reconstruction algorithm, and a FE mesh generator for the SMC composites are developed. First, micro-CT image processing is conducted to estimate probabilistic distributions of two critical features, such as fiber chip orientation and distribution that are highly related to mechanical performance. Second, a reconstruction algorithm for 3D fiber chip packing is developed in consideration of the overlapping effect between fiber chips. Third, the macro-scale behavior of the SMC is predicted by the multiscale analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.10 s.241
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• pp.1329-1335
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• 2005

An aluminum or CFRP (Carbon Fiber ReinfDrced Plastics)is representative one of light-weight materials but its axial collapse mechanism is different from each other. The aluminum member absorbs energy by stable plastic deformation, while the CFRP member absorbs energy by unstable brittle failure with higher specific strength and stiffness than those in the aluminum member. In an attempt to achieve a synergy effect by combining the two members, aluminum CFRP compound square members were manufactured, which are composed of aluminum members wrapped with CFRP outside aluminum square members with different fiber orientation angle and thickness of CFRP, and axial collapse tests were performed fur the members. The axial collapse characteristics of the compound members were analyzed and compared with those of the respective aluminum members and CFRP members. Test results showed that the collapse of the aluminum CFRP compound member complemented unstable brittle failure of the CFRP member due to ductile characteristics of the inner aluminum member. The collapse modes were categorized into four modes under the iuluence of the fiber orientation angle and thickness of CFRP. The absorbed energy Per unit mass, which is in the light-weight aspect was higher in the aluminum CFRP compound member than that in the aluminum member and the CFRP member alone.

• Bulletin of the Korean Chemical Society
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• v.12 no.6
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• pp.612-617
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• 1991

The approximate rates and stoichiometry of the reaction of excess 1,3,2-biphenyldioxaborepin [2,2'-biphenoxyborane (BPB)] with selected organic compounds containing representative functional groups under the standardized conditions (tetrahydrofuran, hydride to compound being 4 : 1, room temperature) was examined in order to define the characteristics of the reagent for selective reductions and compare its reducing power with those of other substituted boranes. The results indicate that BPB is unique and the reducing power is much stronger than that of other dialkoxyboranes, such as catecholborane and di-s-butoxyborane. BPB reduces aldehydes, ketones, quinones, lactones, tertiary amides, and sulfoxides readily. Carboxylic acids, anhydrides, esters, and nitriles are also reduced slowly. However, the reactions of acid chlorides, epoxides, primary amides, nitro compounds, and disulfides with this reagent proceed only sluggishly.

• Bulletin of the Korean Chemical Society
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• v.15 no.8
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• pp.644-649
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• 1994

The approximate rates and stoichiometry of reaction of excess dipyrrolinoaluminum hydride (DPAH) with selected organic compounds containing representative functional groups under standardized conditions (tetrahydrofuran, 0, reagent : compound=4 : 1) were examined in order to define the characteristics of the reagent for selective reductions. The reducing ability of DPAH was also compared with that of bis(diethylamino)aluminum hydride (BEAH). The reagent appears to be stronger than BEAH, but weaker than the parent reagent in reducing strength. DPAH shows a unique reducing characteristics. Thus, the reagent reduces aldehydes, ketones, esters, acid chlorides, epoxides, and nitriles readily. In addition to that, ${\alpha},\;{\beta}$-unsaturated aldehyde is reduced to the saturated alcohol. Quinone are reduced cleanly to the corresponding 1,4-reduction products. The examination for possibility of achieving a partial reduction to aldehydes was also performed. Both primary and tertiary aromatic carboxamides are converted to aldehydes with a limiting amount of DPAH. Finally, disulfides and sulfoxides are readily reduced to thiols and sulfides, respectively.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.243-249
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• 1998

The reaction of alcohol with a solution of thexylborane (ThxBH2) in tetrahydrofuran (THF) provides a new class of mild and selective reducing agents, thexylalkoxyboranes (ThxBHOR: R=Et, i-Pr, i-Bu, s-Bu, t-Bu, Ph). In order to elucidate the effect of the alkoxy group in reduction reactions, the reducing power of ThxBHOR toward selected organic compounds containing representative functional groups under practical conditions (THF, 25°, the quantitative amount of reagent to compound) has been investigated. Generally, the reactivity of ThxBHOR is largely dependent upon the alkoxy substituent. ThxBHOR can be synthesized from a variety of alcohols, thus allowing control of the steric and electronic environment of these reagents.

• YAKHAK HOEJI
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• v.50 no.1
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• pp.52-57
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• 2006

The activation of cyclin dependent kinase 4 (CDK4) is found in more than half of all human cancers. Therefore CDK4 is an attractive target for the development of a novel anticancer agent. For mass screening of CDK4 inhibitor, we set up in vitro kinase assay for CDK4 activity using a cyclin D1-CDK4 fusion protein, which is constitutively active and exhibits enhanced stability. From the screening of representative compound library of Korea Chemical Bank, we found that 7-chloro-4-nitro-benzo[1,2,5]oxadiazole 1-oxide (FBP-1248) selectively inhibited CDK4 activity in vitro by ATP competitive manner. This compound prevented the phosphorylation of retinoblatsoma tumor suppressor protein, Rb, and inhibited cell growth through cell cycle arrest. In summary, we developed an efficient assay system for CDK4 activity in vitro and identified the CDK4 inhibitory compound, FBP-1248.