• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1998.10a
• /
• pp.258-265
• /
• 1998

Application of the flat shell element with drilling D.O.F to linear buckling analysis of thin-walled structures is presented in this paper. The shell element has been developed basically by combining a membrane element with drilling D.O.F. and Mindlin plate bending element. Thus, the shell element possesses six degrees-of-freedom per node which, in addition to improvement of the element behavior, permits an easy connection to other six degrees-of-freedom per node elements(CLS, Choi and Lee, 1995). Accordingly, structures like folded plate and stiffened shell structure, for which it is hard to find the analytical solutions, can be analyzed using these developed flat shell elements. In this paper, linear buckling analysis of thin-walled structures like folded plate structures using the shell elements(CLS) with drilling D.O.F. to be formulated and then fulfilled. Subsequently, buckling modes and the critical loads can be output. Finally. finite element solutions for linear buckling analysis of folded plate structures are compared with available analytic solutions and other researcher's results.

• Journal of Korean Society of Transportation
• /
• v.31 no.2
• /
• pp.45-59
• /
• 2013

This study deals with the comparative analysis between two freight demand estimation methods : Unimodal O/D based method and P/C based method. The data of access/egress truck trips has been omitted from the Korean freight unimodal O/D of KTDB. This is because KTDB's unimodal O/D has not marked the series of unlinked trips down as the whole freight intermodal transport and surveyed only the main-haul trips of them. For these reasons, freight intermodal transport mechanism has not been analysed perfectly with Korean unimodal O/D data. This study tries to estimate P/C table of Korean Import/Export container freight and develop the MCC(Multimodal Channel Choice) model. Then, comparing unimodal O/D based method and P/C based method in terms of the switch commodities between production point(the initial point of freight transport) and consumption point(the terminal point of freight transport), unimodal commodities, and commodities on links is conducted. The results show that the P/C based method is able to simulate the freight intermodal transport.

• Bulletin of the Korean Chemical Society
• /
• v.22 no.12
• /
• pp.1333-1336
• /
• 2001

A theoretical analysis is presented for the multichannel type resonance at energies above the dissociation threshold to O(1D) in the photodissociation of OH. Dissociations to both oxygenic terms O(3P) and O(1D) are treated. Total cross sections for producing these oxygen terms display asymmetric resonance due to the quantum interference resulting from complicated interplay of electronic states correlating to these two oxygenic terms. The branching ratios of O(3Pj, j = 0, 1, 2), and the vector properties of O(3Pj, j =0,1,2) and O(1D) display extensive changes near the threshold resonance as the result of the interactions among the electronic states correlated with O(3P) and O(1D).

• Journal of Korean Society of Transportation
• /
• v.36 no.3
• /
• pp.203-215
• /
• 2018

This study suggests a method to construct large scale dynamic O/D reflecting the characteristic that the passengers' travel patterns change according to the land use patterns of the destination. There are limitations in the existing research about dynamic O/D estimation method, such as the difficulty of collecting data, which can be applied only to a small area, or limiting to a specific transportation network such as highway networks or public transportation networks. In this paper, we propose a method to estimate dynamic O/D without limitation of analysis area based on transportation resources that can be easily collected and used according to the big data era. Clustering analysis was used to calculate the departure time trip distribution ratio based on arrival time and departure time trip distribution function was estimated by each cluster. As a result of the comparison test with the survey data, the estimated distribution function was statistically significant.

• Journal of the Ergonomics Society of Korea
• /
• v.31 no.6
• /
• pp.785-791
• /
• 2012

Objective: The aim of this study was to investigate the correlation between 3D visual fatigue and physiological measures by canonical correlation analysis enabling to categorical correlation. Background: Few studies have been conducted to investigate the physiological mechanism underlying the visual fatigue caused by processing 3D information which may make the cognitive mechanism overloaded. However, even the previous studies lack validation in terms of the correlation between physiological variables and the visual fatigue. Method: 9 Female and 6 male subjects with a mean age of $22.53{\pm}2.55$ voluntarily participated in this experiment. All participants were asked to report how they felt about their health sate at after viewing 3D. In addition, Low & Hybrid measurement test(Event Related Potential, Steady-state Visual Evoked Potential) and for evaluating cognitive fatigue before and after viewing 3D were performed. The physiological signal were measured with subjective fatigue evaluation before and after in watching the 3D content. For this study suggesting categorical correlation, all measures were categorized into three sets such as included Visual Fatigue set(response time, subjective evaluation), Autonomic Nervous System set(PPG frequency, PPG amplitude, HF/LF ratio), Central Nervous System set(ERP amplitude P4, O1, O2, ERP latency P4, O1, O2, SSVEP S/N ratio P4, O1, O2). Then the correlation of three variables sets, canonical correlation analysis was conducted. Results: The results showed a significant correlation between visual fatigue and physiological measures. However, different variables of visual fatigue were highly correlated to respective HF/LF ratio and to ERP latency(O2). Conclusion: Response time was highly correlated to ERP latency(O2) while the subjective evaluation was to HF/LF ratio. Application: This study may provide the most significant variables for the quantitative evaluation of visual fatigue using HF/LF ratio and ERP latency based human performance and subjective fatigue.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.43 no.5
• /
• pp.462-473
• /
• 2010

Inductions of hybrids and reciprocal hybrids between Oryzias dancena and O. javanicus (ODJ and OJD) were conducted and backcross hybrids between female O. dancena and male ODJ were also produced for biological and cytogenetic analysis. Embryonic development of ODJ and OJD were compared with those of their parents. Developmental time was fastest in O. dancena and ODJ, followed by O. javanicus and OJD. Oryzias dancena hatched 11 days (d) after fertilization, ODJ at 13 d, O. javanicus at 14 d and OJD at 15 d. The abnormality of external morphology rate in ODJ was 10.6%; however, OJD showed a high degree of abnormality, over 90%. The proportion of males was 90.0% and 31.3% for ODJ and OJD, respectively. Cytogenetic analysis was conducted to obtain basic information for genetic identification of O. dancena, O. javanicus and their hybrids. The karyotypes of all experimental groups showed 2n=48 chromosomes and the fundamental number (FN) was 48. The first pair carried secondary constrictions near the centromeric regions. Erythrocyte area and volume were $9.8\;{\pm}\;0.5\;{\mu}m^2$ and $18.2\;{\pm}\;1.0\;{\mu}m^3$, respectively, for O. dancena, $8.3\;{\pm}\;0.5\;{\mu}m^2$ and $15.8\;{\pm}\;1.5\;{\mu}m^3$ in O. javanicus, and $18.3\;{\pm}\;0.5\;{\mu}m^2$ and $15.7\;{\pm}\;1.3\;{\mu}m^3$ in ODJ. Erythrocyte area and volume in ODJ were similar to those of O. javanicus. In backcross hybrids between female O. dancena and male ODJ, all embryos failed to develop and died in the late gastrula stage.

• Natural Product Sciences
• /
• v.11 no.1
• /
• pp.10-12
• /
• 2005

Flavonol galactosides were isolated from the EtOAc fraction of Artemisia apiacea by repeated column chromatography. Their structures were elucidated as $isorhamnetin-3-O-{\beta}-D-galactoside$ (1) and $quercetin-3-O-{\beta}-D-galactoside$ (2) by chemical and spectroscopic analysis. This is the first report on the isolation of compound 2 from this plant.

• Korean Journal of Pharmacognosy
• /
• v.53 no.1
• /
• pp.16-20
• /
• 2022

Five ent-kaurane type diterpene glycosides were isolated from the aerial parts of Inula britannica var. chinensis Regel (Compositae) through repeated column chromatography. Their chemical structures were elucidated as 16β-H-ent-kauran-19-oic acid-19-O-β-D-glucopyranoside (1), 16β-hydroxy-17-acetoxy-ent-kauran-19-oic acid-19-O-β-D-glucopyranoside (2), 16β,17-dihydroxy-ent-kauran-19-oic acid-19-O-β-D-glucopyranoside (3), 16α,17-dihydroxy-ent-kauran-19-oic acid-19-O-β-D-glucopyranoside (4) and 17-O-β-D-glucopyranosyl-16β-H-ent-kauran-19-oic acid-19-O-β-D-glucopyranoside (5), respectively, by spectroscopic analysis. Among these compounds, 1-4 were isolated for the first time from this plant.

• Conservation Science in Museum
• /
• v.23
• /
• pp.71-90
• /
• 2020

The scientific analysis of a 'F-51D Mustang Fighter'(Registered Cultural Heritage 666), one of the War Memorial of Korean collections, was carried out. The paint layer and canopy were discolored due to a constant outdoor exhibit. The results obtained through the scientific survey and analysis processes were intended to be used as basic data for the future dismantling and restoration of the fighter. The analysis results for the pigment components have confirmed red oxide of iron, Fe₂O₃ organic pigments, such as Cobalt Blue, phthalocyanine blue, etc., yellow PbCrO₄, white TiO₂, black Fe₃O₄, and gray Fe₃O₄ + TiO₂. It has been also confirmed that Alkyd resin was mainly used for painting. The fighter's canopy was Poly methyl methacrylate(PMMA), and Al was detected as the main component of the fighter body, wings, and tails.

• Preventive Nutrition and Food Science
• /
• v.2 no.2
• /
• pp.83-88
• /
• 1997

Anthocyanin pigments of purple sweet potato roots (Ipomoea batatas L.) were extracted with 0.5% TFA (Trifluoroacetic acid) in 95% EtOh, and further isolated an purified by Amberlite XAD-7 and ODS column chromatography, and final preparative HPLC. Among nine anthocyanins isolated, the structure of three major anthocyanins were identified as 3-O-(6-O-trans-caffeyl)-2-O-(6-O-trans-caffeylglucopyranosyl)-$\beta$-D-glucopyranosyl-5-O-($\beta$-D-glucopyranosyl)-peonidin, 3-O-(6-O-trans-caffeyl)-2-O-(6-O-trans-feruloyl-glucopyranosyl)-$\beta$-D-glucopyranosyl-5-O-($\beta$-D-glucopyranosyl)-peonidin, and 3-O-(6-O-trans-caffeyl)-2-O-(6-O-p-hydroxylbenzoylglucopyranosyl)-$\beta$-D-glucopyranosyl)-peonidin, by using UV-visible absorption spectra, $^1$H-NMR and FAB-MS analysis.