• Transactions on Electrical and Electronic Materials
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• v.10 no.6
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• pp.212-216
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• 2009

The spatial distribution of the optogalvanic (OG) signal in argon at the 801.489 nm ($1s_5-2p_8$ transition at the metastable level in Paschen notation) was investigated in the radial direction of a hollow cathode discharge tube. The results of this experiment showed that the OG signal amplitude decreases in accordance with the following two conditions; first, the level of discharge current and second, the distance from the cathode dark space. These results can be quantified by analyzing the electron density profile along the discharge regions, which can directly influence the collisional ionization induced by electron impact.

• Elastomers and Composites
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• v.50 no.3
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• pp.175-183
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• 2015

A series of fluorinated aromatic poly(hydroxyamide)s (PHAs) were synthesized by direct polycondensation of diacides containing 2,6-dimethylphenoxy group and quinoxaline ring in the main chain with 2,2-bis-(3-amino-4-hydroxyphenyl) hexafluoropropane. The PHAs had relatively low inherent viscosities in the range of 0.35~0.43 dL/g at $35^{\circ}C$ in DMAc solution. All PHAs exhibited excellent solubility in aprotic solvents such as NMP, DMAc, DMF and DMSO as well as in common organic solvents such as pyridine, THF, and m-cresol at room temperature. However, the poly(benzoxazole)s (PBOs) were quite insoluble in all organic solvents except partially soluble in concentrated sulfuric acid. The PBOs showed glass transition temperatures between 233 and $284^{\circ}C$ by DSC and maximum weight loss temperatures in the range of $536-546^{\circ}C$ by TGA.

• Journal of the Korean Home Economics Association
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• v.42 no.3
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• pp.91-104
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• 2004

This study analyzes the critical factors that decide the job continuity of married women after one of their life events, childbirth. It is based on the employment data from KLIPS(Korea Labor and Income Panel Study). Vols. 1-4, having observed 128 young mothers who gave birth to children after 1997. The analysis showed that women's employment after their maternity leave depend on whether new mother return to their previous job or not. The Following results are obtained: First, women's age, education, availability of caretakers for their children, and family income have a positive effect on the women's return to their pre-leave employers after childbirth. Second, professional or office work and the frequency of job transition before childbirth have a positive effect on women's employment in new jobs after childbirth. Third, women's age, availability of caretakers of their children, and professional or office work are critical factors that have a positive effect on women's job continuity after childbirth, whereas the frequency of job transitions has a negative effect on employment for women.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.10
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• pp.798-804
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• 2012

This paper focuses on thermal properties of a newly prepared composite material by nano-silica and micro-silica mixture. Nano-silica and micro-silica mixture composites were made by dispersing surface treated nano-silica(average radius: 10 nm) and micro-size silica in epoxy resin. To investigate the effects of nano-silica and micro-size silica mixture(ENMC), the glass transition temperature (Tg), coefficients of thermal expansion(CTE) and elastic modulus of DMA properties by DSC, TMA and DMA devices were measured for the ENMC according to increase nano-silica addition contents and EMC. All properties of the neat epoxy were improved by the addition of micro-silica, which was improved much further by the addition of surface treated nano-silica to the EMC system.

• School Mathematics
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• v.2 no.1
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• pp.165-181
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• 2000

The teaching-learning methods of figures using computers make loose the difficulties of geometry education from the viewpoint that the abstract figures can be visualized and that by means of this visualization the learning can be accomplished through the direct experience or control. In this thesis, we present a teaching-learning method of figures using Cabri II so that the learners establish their knowledge obtained through their search, investigation, supposition and they accomplish the positive transition to advanced 1earning. So the learners extend their ability of sensuous intuition to their ability of logical reasoning through their logical intuition.

• Journal of Korea Multimedia Society
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• v.7 no.6
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• pp.806-813
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• 2004

Internet users are increasingly depending on acquiring and spreading a variety of information from home pages and they are also making use of education systems based on the internet. This study suggests an efficient method to make learners study Chinese Letters with ease and fun through the internet. The detailed methods of attaining Chinese letters Using Edutainment system are divided into 5 elements as follows. Utilizing the transition process of the letters, using games, applying animation and through switching over from Chinese letters to Korean letters and vice versa including making use of the sound of letters and their meanings.

• Bulletin of the Korean Chemical Society
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• v.4 no.5
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• pp.208-211
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• 1983

Kinetic studies of nucleophilic substitution reactions of para-substituted benzylchlorides with anilines were conducted in a range of MeOH-MeCN mixtures at $55.1^{\circ}C$. Hammett ${\rho}_C$, ${\rho}_N$ values and Bronsted ${\beta}$ values were determined, in other to examine the transition state variations caused by changes in nucleophiles, substituents and solvents properties (${\pi}^{\ast}$ and ${\alpha}$). Applications of potential energy surface (PES) and quantum mechanical (QM) models of transitheion state characterization lead us to conclude that the reaction proceeds via the dissociative $S_N2$ mechanism.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.312-315
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• 2018

Although the reversibility of 10,12-pentacosadiynoic amino meta-acid(PCDA-mBzA) against temperature and pH was reported, the modulation of reversibility by ion adsorption at terminal functional group has not been investigated. In this work, we developed a simple method for modulating the reversibility of PCDA-mBzA films upon a thermal stimulus by cadmium ion adsorption inducing the breakage of the outer hydrogen bonding of two hydrogen bonds, which are responsible for the reversible properties of PCDA-mBzA. External reflection-Fourier transform infrared (ER-FTIR) analyses revealed that the hydrogen bonding between the carboxylic acid groups was broken through ion adsorption and only a single hydrogen bond between the amide groups remained in the PCDA-mBzA polymer. In addition, PCDA-mBzA films could recover their original property through cadmium ion desorption. These results present that the transition between reversibility and irreversibility can be modulated artificially simply through the adsorption and desorption of metal ions.

• East Asian mathematical journal
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• v.38 no.2
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• pp.165-185
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• 2022

The six core competencies have been emphasized in the mathematics curriculum revised in 2015. In particular, the communication is very important for students' representing their own thinking and enhancing much higher mathematical thinking. Based on this competency, this study selected the four elements of the communication such as the understanding of mathematical representation, development and transition of mathematical representation, the representation of his own thinking, the understanding of the others' thinking. And also this study selected the domain of function which is comprised of the content of the coordinate plane, the graph, proportionality in the seventh grade mathematics textbook. By the subject of the ten kinds of textbook, this study examined how the four elements of the communication competency were shown in each textbook.

• Journal of Koreanology Reviews
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• v.1 no.2
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• pp.11-18
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• 2022

International negotiation and cooperation for sustainable development currently emphasize three themes on which environmental policies are developed. South Korea emphasizes two of the three themes; climate change and the 2030 Agenda for Sustainable Development. South Korea has taken a leadership role in the international arena regarding these topics, actively participating in the United Nations Framework Convention on Climate Change (UNFCCC) and the negotiations for the 2030 Agenda (Jung, 2018). South Korea has taken a number of steps to address climate change, both domestically and internationally. Domestically, it has implemented several policies and methods to lessen GHG emissions and transition to a low-carbon economy. It has implemented an Emissions Trading Scheme, the largest in the world, a renewable energy portfolio standard, and aimed at accomplishing carbon neutrality by 2050. South Korea is also actively involved in executing the Sustainable Development Goals (SDGs) and has established a national committee to ensure their successful implementation. The group is made up of representatives from the private sector, government ministries, and civil society organizations. It is focused on monitoring the progress of the SDGs and providing policy and financial support for their implementation.