• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.635-642
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• 2014

The space charge behaviors of oil-paper insulation affect the stability and security of oil-filled converter transformers of traditional and new energies. This paper presents the results of the electrical aging of oil-impregnated paper under AC-DC combined voltages by the pulsed electro-acoustic technique. Data mining and feature extractions were performed on the influence of electrical aging on charge dynamics based on the experiment results in the first stage. Characteristic parameters such as total charge injection and apparent charge mobility were calculated. The influences of electrical aging on the trap energy distribution of an oil-paper insulation system were analyzed and discussed. Longer electrical aging time would increase the depth and energy density of charge trap, which decelerates the apparent charge mobility and increases the probability of hot electron formation. This mechanism would accelerate damage to the cellulose and the formation of discharge channels, enhance the acceleration of the electric field distortion, and shorten insulation lifetime under AC-DC combined voltages.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1140-1144
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• 2002

Molecular relaxation behaviors of crystalline glucose anhydrous, crystalline glucose monohydrate, and amorphous glucose with different particle sizes were observed by measuring spin-spin relaxation time constant $(T_2)$ at the temperature range of $-20\;to\;110^{\circ}C$ using temperature-controlled low field nuclear magnetic resonance spectroscopy. No change in $T_2$ values of crystalline glucose anhydrous was observed throughout the temperature range, whereas $T_2$ values of crystalline glucose monohydrate and amorphous glucose increased from around $45\;and\;65^{\circ}C$, respectively. These results indicate that molecular mobility of crystalline glucose anhydrous does not change even at temperature higher than $100^{\circ}C$ and that the stability of powdered glucose could be improved by increasing the particle size of materials.

• Journal of the Korean Dietetic Association
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• v.26 no.3
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• pp.208-220
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• 2020

In modern society, the online to offline (O2O) market has become an emerging market. Based on social and cultural phenomena, the importance of "FOODTECH" linked with mobile applications is growing in the food and restaurant industry. This study examined subjective food application service quality, perceived value, and post-purchase behavior intentions. According to this study, of foodtech service quality attributes, only information, mobility, and reliability had positive (+) relationships with perceived value. However, foodtech service quality attributes did not have a direct impact on behavior intentions. Perceived values had a positive (+) relationship with behavior intentions and showed full mediation effects between foodtech service quality attributes and behavior intentions. Based on these results, future research on the relationship among food application service quality, perceived value, and post-purchase behavior intentions is needed.

• Environmental Engineering Research
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• v.23 no.1
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• pp.76-83
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• 2018

Spatial moment analysis has been performed on the concentration of the first species in a multispecies solute transport in porous media. Finite difference numerical technique was used in obtaining the solute concentration. A constant continuous source of contaminant was injected at the inlet of the domain. Results suggest that the decaying of solute mass increases as the magnitude of mean fluid velocity increases. The dispersion coefficient is highly time dependent under decaying of solutes with a complex behavior of mixing of solutes. The solute mobility and mixing varies non-linearly with time during its initial period, while the same ceases with higher decay rates of the first species much faster.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.375-379
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• 2004

The purpose of this study is to analyze the evolution of mobility after the commercial opening of french TGV through an examination on the precedent studies. The result of this study is as follows: Firstly, the TGV is competitive against the airplanes and automobiles within the 2 or 3 hours' service area, especially in the business trip markets. But in the recreational trips over this service area, 3 or 4 hours, the TGV remains as an important mode of transportation. Secondly, in a range within approximately 200 km, 1 hour by TGV, the french high speed train is not competitive against the automobiles by the lack of flexibility and commodity which are normally providing by the automobiles. This study shows the importance of permanent monitoring system on the KTX travellers' behavior to strengthen the market share of KTX.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.115-119
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• 2001

Contaminant retardation factor is derived from the colloidal and contaminant transport equations for a four-phase porous medium: an aqueous phase, two mobile colloidal phases, and a solid matrix. It is assumed that the contaminant sorption to solid matrix and colloidal particles and the colloidal deposition on solid matrix follow the linear isotherms. The behavior of the contaminant retardation factor in response to the change of model parameters is examined employing the experimental data of Magee et al. (1991) and Jenkins and Lion (1993). In the four-phase system, the contaminant retardation factor is determined by both the contaminant association with solid matrix and colloidal particles and the colloidal deposition on solid matrix. The contaminant mobility is enhanced when the affinity of contaminants to mobile colloids increases. In addition, as the affinity of colloids to solid matrix decreases, the contaminant mobility increases.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.2
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• pp.71-75
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• 2014

To observe the optical characteristic of oxide semiconductor depending on the degree of bonding structures, SiOC, ZnO and IGZO were prepared by the RF magnetron sputter system and chemical vapor deposition. Generally, crystal ZnO, amorphous SiOC and IGZO changed the optical characteristics in according to the electro-chemical behavior due to the oxygen vacancy at an interface between different groups. Transmittance of SiOC and IGZO with amorphous structures was higher than that of ZnO with crystal structure, because of lowering the carrier concentration due to the recombination of electron and holes carriers as oxygen vacancies. Besides, the energy gap of amorphous SiOC and IGZO was higher than the energy gap of crystal ZnO. The diffusion mobility of holes is higher than the drift mobility of electrons.

• KDI Journal of Economic Policy
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• v.40 no.4
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• pp.65-80
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• 2018

This paper examines the differences between the subsequent careers of high school and college graduate workers based on a direct role of college graduation with regard to the revelation of workers' individual abilities. Using NLSY79, we document a positive relationship between off-the-job training/performance-pay jobs and ability for high school graduates at the early stages of their careers. However, this relationship is less prominent for college graduates. Moreover, we show that high ability is associated with more jobs, which reflects higher job mobility, only for high school graduates. We argue that these patterns are the result of productivity-revealing behavior of high school graduates, whose individual abilities, unlike college graduates, is not observed precisely at the beginning of their careers.

• The Journal of the Korea Contents Association
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• v.11 no.9
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• pp.63-75
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• 2011

A number of process algebras have been proposed to develop distributed mobile real-time systems: pi-Calculus, Mobile Ambients Calculus, Bigraph, etc. However, as the systems get large and complex, the algebras become less suitable for understanding the interactions and mobility of the processes of the systems due to the size and complexity. Therefore it is necessary to handle the size and complexity for systematic understanding of the systems. This paper handles the size and complexity with a method of abstraction on sequences of interactions and movements of processes in the systems, which can be further organized in the form of hierarchically structured lattices, namely, Prism. The theoretical principle of the abstraction is based on a new concept of Behavior Ontology, which is extended from Active ontology. Prism allows the systems to be analyzed in the perspective of the lattices in Prism, which are characterized by the hierarchically organized behavioral properties of the developing systems, for systematic understanding the systems. In this way, the complexity of the interactions and the movements can be handled systematically in the semantically and hierarchically organized structure of the behavior.

• Analytical Science and Technology
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• v.34 no.4
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• pp.143-152
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• 2021

Capillary electrophoresis (CE) is an effective technique to study chiral recognition because it offers flexibility in adjusting vital factors. Currently, various available cyclodextrins (CDs) can be employed for the chiral separation of numerous analytes. Herein, we investigate the enantioseparation behavior of lipoic acid enantiomers in various types of single and dual CD systems through CE. Additionally, several impacted CE parameters were optimized through the systematic investigation based on the design of experiment (DoE) concept for a single system comprising a heptakis (2,3,6-tri-O-methyl)-β-CD and a dual system containing the combination of the single CD with a sulfated-β-CD. Consequently, absolute enantioresolution was obtained within 15 min on a common standard bare fused-silica capillary (64.5/56 cm in total/effective length, 50/365 ㎛ inner/outer diameter), maintained at 15 ℃ and at an applied voltage of 24 kV. The optimal background electrolyte consisted of 6 mM heptakis (2,3,6-tri-O-methyl)-β-CD dissolved in the solution of 58 mM borate buffer at pH 10. Furthermore, the results of apparent binding constant experiments indicated that the S-enantiomer-heptakis (2,3,6-tri-O-methyl)-β-CD complex exhibited a stronger affinity than its R-enantiomer counterpart. The obtained electrophoretic mobility values could be utilized to interpret the resolution achieved at various CD concentrations and the mobility behavior of the complexes elucidated the migration order of the enantiomers in an electropherogram.