• Journal of Integrative Natural Science
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• v.11 no.2
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• pp.113-120
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• 2018

This study was planned to prepare the high strength hydrogel ophthalmic lens containing isocyanate group and nanoparticles. HDI with carbon nanoparticles were used as additives for the basic combination of HEMA, MA and MMA, and the materials were copolymerized with EGDMA as the cross-linking agent and AIBN as the initiator. The mixture was heated at $100^{\circ}C$ for an hour to produce the high performance hydrogel ophthalmic lens by cast mold method. Measurement of the physical characteristics of the produced material showed that the refractive index was in the range of 1.4027~1.4600, water content 25.21~44.01%, contact angle $54.18{\sim}72.94^{\circ}$, visible light transmittance 53.03~92.09%, and tensile strength 0.1024~0.2359 kgf and breaking strength was 0.0872~0.2825 kgf. The results showed an increase of refractive index while the decrease in water content. And also, the breaking strength was highest when the addition ratio of HDI was 5%(wt). As a result of the absorbance measurement, no significant difference was observed in all the samples, so it can be judged that the stabilization of nanoparticles in the polymer was maintained.

• Journal of Environmental Science International
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• v.17 no.8
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• pp.925-932
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• 2008

Manufactures of automotive repair finishes are tending to reduce more and more the level of volatile organic compounds (VOCs) in their paint processes in order to comply with increasingly strict environmental legislation. The production of high solids paints is a way to solve this problem. However, the application of high-solids paints is limited primarily by the viscosity of resin which is strongly related to painting ability: the higher solid content, the lower desired property. In this study, alkyl copolymer with low viscosity was synthesized by the introduction of the monomers with long-side chains and functional groups which improve flexibility and cross-linking density, respectively. The solid content of the paint prepared with the synthesized resin was 80wt% and its VOCs was reduced by 20%, compared to the commercialized paint. Also, the physical and mechanical properties of coatings on steel sheets were similar to commercialized one.

• Journal of the Korean institute of surface engineering
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• v.30 no.4
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• pp.255-261
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• 1997

Thin film batteries can be used as a micro power source for electronic in which minute power is needed. In this study, lithium phosphorous oxynitride(LIPON) thin films were deposited as an eletrolyte for lithium ion batteries using RF magentron sputtering of lithium phosphate in N2. Ti was also added into the LIPON films as a second network former to enhance the ioinc conductivity of the films. The optimum conditions for LIPON film deposition were sought and the electrolyte with the conductivity of $2.5 \times 10^{-6}$S/cm was obtained at the condition of RF power 4.4 W/$\textrm{cm}^2$, process pressure 10 mtorr and pure nitrogen ambience. Furthermore, the conductivity of LIPON films was increased from $2.5 \times 10^{-6}$S/cm to $8.6 \times 10^{-6}$S/cm by the doping of 2.4at.% Ti. It was also found that by adding Ti to LIPON films, Li content was increased and nitrogen content that reported having the cross-linking effect on LIPON films was also increased as confirmed XPS.

• Journal of the Korean Ceramic Society
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• v.44 no.5 s.300
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• pp.184-189
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• 2007

In this study, a novel-processing route for producing microcellular cordierite ceramics has been developed. The proposed strategy for making the microcellular cordierite ceramics involves three steps: (i) fabricating ceramic-filled preceramic foams by heating a mixture of polysiloxane, expandable microspheres, talc, and alumina in a mold, (ii) cross-linking the foamed body, and (iii) transforming the body into microcellular cordierite ceramics by sintering. Cu jig was used for near net shaping in the foaming step. The experimental variables such as the shape of foaming jig and the content of expendable microsphere were investigated. By controlling the content of expendable microsphere, it was possible to make the porous cordierite ceramics with cell density of ${\sim}1.0{\times}10^9\;cells/cm^3$.

• International Journal of Knowledge Content Development & Technology
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• v.7 no.2
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• pp.41-51
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• 2017

Nowadays, research data repositories (RDR) have become progressively widespread all over the world. To expand repository services and build up inbound linking strategy, organizations list their repositories with so called Global Registries. Accordingly, such registries should be carefully described by the related data. In this study, I explore the metadata schema of re3data.org. I collect and analyze descriptions from the listed repositories, and come up with some suggestions concerning possible improvements to the metadata schema. To accomplish this, I develop a crawler program, which collects necessary data from the re3data.org. Based on the analysis results, I have identified two issues that required elements is missing, one issue that required element value is missing when the corresponding property is applied, five inconsistency issues with re3data controlled vocabulary, six issues with undescribed optional elements, and two inconsistency issues between the elements and their attributes which do not pair with. I believe this discussion can facilitate improvements to the existing re3data.org schema and further help researchers who analyze data repository trends.

• Journal of Korea Game Society
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• v.22 no.1
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• pp.3-18
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• 2022

This study focuses on transtextuality of Easter egg and its effect on replayability. This paper categorizes Easter eggs of digital game into five types based on game elements, and applies Gerard Genette's transtextuality theory by analyzing function and meaning of Easter eggs based on quotation, allusion, and annotation of intertext and paratext. In conclusion, Easter eggs as transtext form game ritual by linking inside and outside of the game, as well as developers and players. Through this process, Easter egg enhances replayability of digital games by extending the narrative of the game.

• Journal of Technologic Dentistry
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• v.45 no.4
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• pp.111-117
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• 2023

Purpose: This study aims to determine the status of dental technician's continuing education and licensing reporting and provide basic data that can aid in improving the operation of progressive continuing education and licensing reporting and development programs. Methods: This study included dental technicians nationwide who attended the 2023 Korea Dental Technology Expo & Scientific Conference and responded to an online survey from July 21 to July 23, 2023. In total, 180 copies were analyzed. The reliability of satisfaction with continuing education demonstrated a Cronbach's α of 0.924. IBM SPSS Statistics version 21.0 (IBM) was used to statistically analyze the collected data. Results: Satisfaction with continuing education for dental technicians was 2.78, 2.81, 3.21, 2.96, and 2.87 for the number of lectures offered, composition of major fields, lecture content, instructor level, and overall satisfaction, respectively. The average satisfaction with continuing education was 2.93, which was lower than the average (3 points). The investigation revealed that overall improvement was required. Conclusion: Measures for those who have not completed continuing education must be implemented within the government's legal influence by actively using the license reporting system. Strengthening verification of completion of continuing education, improving autonomous disciplinary rights, diversifying the content and learning methods of continuing education, linking with the license reporting system, improving institutional postevaluation, and introducing related policies should be conducted when opening a dental laboratory.

• Journal of Korean Library and Information Science Society
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• v.50 no.4
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• pp.33-55
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• 2019

A marketing platform based on the legal deposit system was designed. It is an e-book distribution platform that systematically binds library networks nationwide by linking with the National Library's deposit system to complete the existing paper that the library should become a publishing platform. The purpose is to bundle e-books into a distribution space and naturally assemble readers to serve as virtual platforms for domestic publishers, authors, bookstores, and platforms running various publishing / subscribing services. The premise is not a sale of e-books, but a rental concept, but the platform is valid regardless. In addition, the platform takes the form of social cooperatives to represent the interests of all members involved in publishing services. The lead-based distribution platform is the most ideal business model to compromise with reality. Conceptually, the service of the publishing content-related industry is a model in which all content is supplied from the lead-bone system, which is a collaborative space, and technically, the central e-book database controls the flow of all content, but the publishing content-related industry takes the form of controlling its flow through virtual.

• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.224-230
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• 2012

In this paper, flame-resisting PMMA(polymethyl methacrylate) sheet was manufactured and its characteristics were tested. PMMA was synthesized by bulk polymerization of a monomer methyl methacrylate with addition of phosphorous flame retardant, triethyl phosphate and ethylene glycol dimethacrylate as a cross linking agent. PMMA sheet was manufactured by using the cell molding method, which does not alter or affect the existing property of PMMA. Then the characteristics of PMMA sheet were tested for the TEP content, the content and curing time of EGDMA. As TEP content increases, the length of carbonization lessens and the amount of char production increases. As a result, it strengthened the effect of flame retardants. But the hardness of the sheet decreased as TEP content increased. However, hardness increased when EGDMA was added up to 3 wt% while curing time was decreased from 3 hours to 2 hours. There was no change of hardness when more than 3 wt% of EGDMA was used.

• Polymer(Korea)
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• v.39 no.3
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• pp.394-402
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• 2015

Modification of polyacrylonitrile (PAN) films by using hydroxylamine (HA) and hydrazine to produce hydroxyl and amine groups, respectively, and to introduce cross-linking of PAN polymers was studied. Modified PAN films obtained by HA and/or hydrazine treatment including a successive or a simultaneous process were analyzed by the degree of conversion, water and N,N'-dimethylformamide (DMF) swelling ratio, FTIR spectra, atom content, and thermal analysis data. PAN films reacted with HA showed increased hydrophilicity and low dimensional stability in water. Hydrazine treatment gave PAN films high dimensional stability of low DMF swelling. Although the DMF swelling ratio of the modified PAN films was dramatically decreased by the successive treatment of hydrazine and HA, the introduction of the hydrophilic functional groups was limited due to the cross-linking. Simultaneous treatment of HA and hydrazine was the most effective method to increase hydrophilicity of PAN films with a high dimensional stability.