• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.147-149
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• 2017

Since the launch of the Herschel Space Observatory, our understanding about the photo-dissociation regions (PDR) has taken a step forward. In the bandwidth of the Fourier Transform Spectrometer (FTS) of the Spectral and Photometric Imaging REceiver (SPIRE) on board Herschel, ten CO rotational transitions, including J = 4 - 3 to J = 13 - 12, and three fine structure lines, including [$C{\small{I}}$] 609, [$C{\small{I}}$] 370, and [$N{\small{II}}$] $205{\mu}m$, are covered. I present our findings from the FTS observations at the nuclear region of M83, based on the spatially resolved physical parameters derived from the CO spectral line energy distribution (SLED) map and the comparisons with the dust properties and star-formation tracers. This article discusses (1) the potential of using [$N{\small{II}$] 205 and [$C{\small{I}}$] $370{\mu}m$ as star-formation tracers; (2) the excitation mechanisms of warm CO in the nuclear region of M83.

• Biomedical Science Letters
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• v.15 no.2
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• pp.105-112
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• 2009

The screening of the anti-cancer activity of the chemical library provided 2-thio-4-aminopyrimidine as the initial hit. The confirmation of structure and biological effect of hit was performed by synthesis and biological evaluation. The optimization of hit was performed by derivatization of substituents while keeping the core structure. The evaluation of growth inhibitory activity was carried out using SRB assay against 6 human cancer cell lines and human fibroblast. The growth inhibitory activity of compounds showed substituent dependency and more than 5 compounds showed complete growth inhibition of cancer cell lines at 10 ${\mu}M$ concentration. Chemical library screening followed by synthetic modification provided possibility that 2-thio-4-aminopyrimidine can be used as a new scaffold for the development of anti-cancer agent.

• Korea Trade Review
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• v.44 no.4
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• pp.153-168
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• 2019

The logistics industry is changing with the diversification of demand and related technology development. Thus, the transportation system is also changing to social problems and environmental damage, and the importance of rail freight is increasing with changes in the international logistics environment. This study analyzes railway freight competition structure using freight volume and suggests improving the competitiveness of railroad freight. To achieve the research purpose, this study was conducted using the Hirshmann-Herfindahl Index(HHI) and Location Quotients(LQ) method. As a result, the concentration trend of railway trends has increased from 0.213 to 0.238 during the last 9 years, and LQ analysis has enabled the identification of local competition lines by item. The study result confirmed that policy measures on railway freight system, railway infrastructure construction and railway operation are necessary to enhance railway competitiveness.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.7
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• pp.609-614
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• 2002

In this study, we investigated the effects of hot water on the aging of URD power cables due to the hot water ingress to power distribution lines. Hot water contacted and non-contacted cables extracted from 2 distribution lines were characterized by the measurement of oxidation induction time(OIT) and chemical structure. In OIT measurement, hot water contacted cables showed the shorter OIT than non-contacted ones. Especially, hot water contacted insulation layer near insulation shield showed the shortest OIT. In chemical structure analysis, the antioxidant content was decreased and the acid concentration was increased by hot water ingress. From this results, it can be concluded that the hot water ingress to power cable may be accelerate the aging by means of antioxidant consumption.

• Journal of electromagnetic engineering and science
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• v.15 no.1
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• pp.26-30
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• 2015

In this paper, a simple equivalent circuit model for a defected ground structure (DGS) microstrip line with stepped impedance slot-lines in the ground plane is presented. In addition, an analytic expression for the resonance frequency of the proposed structure is derived. In equivalent circuit modeling, the capacitance and the inductance of the resonance circuit are evaluated from the dimensions of the etched pattern in the ground plane. The resonance frequencies calculated from the proposed method are compared with those obtained with an electromagnetic (EM) simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.115-120
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• 2002

The rigid body properties of a structure may be estimated easily if the mass-line of the structure could be taken exactly. However, the exact mass-line may be hard to be obtained exactly in experiments. The mass line value can be read from the mass line in frequency response function. However, the mass lines in the frequency response function sometimes show the fluctuation with frequency, and it cannot be read correctly. In this paper, the wavelet transform is applied to obtain the good mass line value. The mass line calculated by using wavelet transform has unique value and showed in the range of fluctuated values of frequency response function. The rigid body properties obtained by wavelet transform also showed better results than those by fourier transform.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.9
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• pp.725-730
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• 2002

The rigid body properties of a structure may be estimated easily if the mass-line of the structure could be taken exactly. However, the exact mass-line nay be hard to be obtained exactly in experiments. The mass line value can be read from the mass line in frequency response function. However, the mass lines in the frequency response function sometimes show the fluctuation with frequency, and it cannot be read correctly. In this paper, the wavelet transform is applied to obtain the good mass line value. The mass line calculated by using wavelet transform has unique value and showed in the range of fluctuated values of frequency response function. The rigid body properties obtained by wavelet transform also showed better results than those by fourier transform.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.166-168
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• 2016

This paper introduces about the structure guide lines of pocket tunneling Field effect transistor. As the pocket length or thickness increase, on-current $I_{on}$ increases. As the pocket thickness is less than 3nm, subthreshold swing (SS) increase. As the dielectric constants of the gate insulator increases, the performance of on-current and subthreshold swing enhances.

• Archives of Pharmacal Research
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• v.18 no.3
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• pp.164-168
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• 1995

In order to elucidate the cytotoxicity-structure correlation of ginseng-derived components, several prosapogenins and sapogenins were prepared from Korean red ginseng (Panax ginseng) saponins by acid hydrolysis or alkaline cleveage, and their chemical structures were identified by a combination of spectral and physical methods. Some of these degradation products showed the cytotoxic activities against various cancer cell lines, A549, SK-OV-3, SK-Mel-2, P388, L1210 and K562. The significant difference in cytotoxicity between stereoisomers was not found and the activity was inversely proportional to the number of sugars linked to sapogenins. Diol-type prosapogenins and sapogenins showed higher cytotoxicity than triol-type ones.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.543-550
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• 1996

Analogues of $2(S)-5, 2^{l}, 5^{l}$-trihydroxy-7, 8-dimethoxyflavanone, a naturally-occurring compound, which had been reported to have potent antitumor activity, were synthesized and examined for the cytotoxicity against three cancer cell lines. Among the intermediate chalcones and synthetic 5-hydroxy-7, 8-dimethoxyflavanone analogues, $({\pm})2^{l}, 5^{l}-dibenzyloxy-5, 7, 8-trimethoxyflavanone$ exhibited about 2-8 times stronger activity than $2(S)-5, 2^{l}, 5^{l}$-trihydroxy-7, 8-dimethoxyflavanone against L1210, K562 and A549 cancer cell lines. In the structure-activity relationship, it is suggested that among analogues of 5-hydroxy-7, 8-dimethoxyflavanone, the existence of two oxygenated groups of para-relation at $C-2^{I} and C-5^{I}$ positions on flavanone B-ring, may be necessary to exhibit effective cytotoxic activity.