• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.454-459
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• 2013

Recently, remote phosphors have been reported for application to white LEDs to provide enhanced phosphor efficiency compared with conventional phosphor-based white LEDs. In this study, a remote phosphor was produced by coating via screen printing on a glass substrate with different numbers of phosphor coating. The paste consists of phosphor, lowest softening glass frits, and organic binders. The remote phosphor could be well controlled by varying the phosphor content rated paste. After mounting the remote phosphor on top of a blue LED chip, CCT, CRI, and luminance efficiency were measured and values of 5300 K, 62, and 117 lm/W were respectively obtained in the 80 wt% phosphor with 3 coating layers sintered at $800^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.9
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• pp.835-843
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• 2008

We have fabricated the source-drain electrodes for OTFTs by screen printing method and manufactured Ag pastes as conductive paste. To obtain excellent conductivity and screen-printability of Ag pastes, the dispersion characteristics of Ag pastes prepared from two types of acryl resins with different molecular structures and Ag powder treated with caprylic acid, triethanol amine and dodecane thiol as surfactant respectively were investigated. The Ag pastes containing Ag powder treated with dodecane thiol having thiol as anchor group or AA4123 with carboxyl group(COOH) of hydrophilic group as binder resin exhibited excellent dispersity. But, Ag pastes(CA-41, TA-41, DT-41) prepared from AA4123 fabricated the insulating layer since the strong interaction between surface of Ag powder and carboxyl group(COOH) of AA4123 interfered with the formation of conduction path among Ag powders. The viscosity behavior of Ag pastes exhibited shear-thinning flow in the high shear rate range and the pastes with bad dispersion characteristic demonstrated higher shear-thinning index than those with good dispersity due to the weak flocculated network structure. The output curve of OTFT device with a channel length of 107 ${\mu}m$ using screen-printed S-D electrodes from DT-30 showed good saturation behavior and no significant contact resistance. And this device exhibited a saturation mobility of $4.0{\times}10^{-3}$ $cm^2/Vs$, on/off current ratio of about $10^5$ and a threshold voltage of about 0.7 V.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.4
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• pp.77-84
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• 2012

The lithographic process depends on a satisfactory ink-in-water emulsion being formed during printing and the speed of wet presses makes the choice of fountain solution vitally important as the ink and fount must react quickly to form a stable emulsion. Ink and water come into contact with each other on the rolls of the press and are forced together in the roll nips. The water is not soluble in the ink since it is slightly fat. Instead, an emulsion is formed, a heterogeneous mass consisting of small water drops mixed into the ink, if the water feed is too great. This emulsification can affect the properties of an off-set ink and negatively affect the printability. So we investigated the effects of the emulsification of phenol free heat-set ink and existing heat-set ink on printed quality, such as amount of ink transfer, printed density, print-through and uniformity. We used Duke emulsification tester for the emulsification of inks, and used IGT printability tester for printed quality. The printed quality were measured by densitometer and were evaluated by the image analysis system. Compared to conventional printing ink, phenol-free ink showed better results of the printability at the emulsification.

• The Research Journal of the Costume Culture
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• v.29 no.4
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• pp.585-602
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• 2021

The purpose of this study is twofold: First, to develop new sustainable design methods (aligned with ethnic elements and traditional culture) combined with three-dimensional digital clothing technology throughout the design process, which can be presented as guideline materials for various fashion designs to be developed in contemporary sensibilities. Second, it is the intention to produce creative fashion designs by incorporating the characteristics and methods of Miao's Huangping batik dyeing technique and to present various possibilities in the fashion design field. The overall design characteristics sought by Miao minority are in line with the complex terrain and the ecological and climatic conditions. Miaoist batik dyeing (registered as part of Chinese national intangible cultural heritage) features unique production methods and patterns. The study results are as follows. First, this attempt has enabled understanding of the national costume culture as Chinese Miao's traditional cultural heritage to be promoted, while the direction of contemporary design development using traditional elements has been presented. Second, the study demonstrated new and innovative expressions and styles relying on three-dimensional digital contouring technology and identified the possibility of developing various designs. Third, it was confirmed that the dyed batik pattern design created by the three-dimensional digital contouring technology could be recombined or expanded as digital printing to express the traditional ethnic designs in a practical manner utilizing digital printing techniques based on traditional characteristics.

• The Research Journal of the Costume Culture
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• v.29 no.1
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• pp.134-151
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• 2021

The aim of this research is to develop a clothing and textiles studio course for preservice home economics teachers applying principles of Project-Based Learning (PBL) and maker education to equip future teachers with the ability to nurture creativity among adolescents. The studio course was developed in the following stages: analysis, design, development, implementation, and evaluation. We concluded that the resulting course met the following objectives extracted from the 2015 revised curriculum of home economics subjects: to promote creative and environmentally-friendly fashion design and styling abilities, gain the ability to use makerspace tools, understand flat pattern making and sewing processes, and develop creative thinking, aesthetic sense, and communication skills. Furthermore, the educational effects of PBL and maker education were confirmed through student comments on the course. Students mentioned the practicality of the material in their actual lives along with their enhanced integration of the subject material, self-directedness, aesthetic sense, ability to learn through trial and error, collaboration and communication, and sharing. Based on results from the implementation and evaluation stages, a clothing and textiles studio course should include the following modules: introduction of terms and tools, submission and sharing of clothing reformation and upcycling techniques, introduction to hand sewing, pouch making, heat-transfer printing, 3D printing, mask making, hat making, vest making, and the final team project on fashion styling. It is important for instructors to provide detailed guidelines on selecting personas for styling, looking for available materials, and selecting materials online.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.30 no.1
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• pp.73-83
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• 2024

In this study, environmental evaluation of high barrier coated paper (coating layer/paper) packaging is conducted in comparison with conventional aluminum laminated (PET/VMPET/LLDPE) plastic packaging. The target product for this packaging is a KF94 mask, which requires a high barrier of water and oxygen to maintain the filtration ability of the mask filter. The functional unit of this study is 10,000 mask packaging materials based on a material capable of blocking oxygen (<1 g/m²day) and moisture (<3 g/m²day) for the preservation of KF94 masks. In order to understand the results easily, paper-based mask packaging system divided into 6 stages (pulp, pulping & paper making, calendaring & coating, printing, packing and waste management), while plastic-based mask packaging consists of 5 stages (material production, processing, printing, packing, waste management) In case of paper-based mask packaging, most contributing stage is calendaring & coating, resulting from heat and electricity production. On the other hand, plastic-based mask packaging is contributed more than 30% by material production, specifically due to linear low density polyethylene and purified terephthalic acid production. The comparison results show that global warming potential of paper-based mask packaging has 32% lower than that of plastic-based mask packaging. Most of other impact indicators revealed in similar trend.

• Fashion & Textile Research Journal
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• v.17 no.6
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• pp.988-995
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• 2015

Gaps between the upper edges of brassiere mold cups and the breasts are one of the most serious issues in realizing comfort wearing of commercial brassieres for small-breasted women. The surplus ease amounts causing the fit problem were measured from 3D wearing images of the small-breasted women's brassieres. The effect after the removing the surplus ease amounts from the upper edge of mold cup was approved by subjective wearing evaluation. Since the volume distribution of mold cup can also affect the wearing sensation of brassiere, the subjective wearing sensation was compared for two brassieres of different volume distributions, V_L, of which volume was concentrated at the lower cup, and V_C, which has the thickest part at the nipple. As the results, the suitable sensation for cup volume and the natural wearing silhouette could be accomplished by removing the surplus ease amounts from the upper edge of mold cup to reduce the gaps between brassieres and the breasts, which could be accomplished through an approach reducing the volume near the upper edge of mold brassiere cup and making the volume concentrated at the lower cup. These works provide a useful information on the design of the brassiere mold cups for small-breasted women. Moreover, modeling methods of 3D scan data and 3D printing technique for making more accurate mold cases used in this research can be helpful to develop and evaluate clothing products in future.

• Smart Structures and Systems
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• v.22 no.2
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• pp.161-166
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• 2018

In the last decade, there has been an exponential increase of scientific interest in smart additive manufacturing (AM) technology. Among the different AM techniques, one of the most commonly applied processes is digital light processing (DLP). DLP uses a digital projector screen to flash an ultraviolet light which cures photopolymer resins. The resin is cured to form a solid to produce parts with precise high dimensional accuracy. During the curing process, there are several process parameters that need to be optimized. Among these, the exposure time affects the quality of the 3D printed specimen such as mechanical strength and dimensional accuracy. This study examines optimal exposure times and their impact on printed part. It was found that there is optimal exposure time for printed part to have appropriate mechanical strength and accurate dimensions. The gel fraction and TGA test results confirmed that the improvement of mechanical properties with the increasing UV exposure time was due to the increase of crosslinked network formation with UV exposure time in acrylic resins. In addition, gel fraction and thermogravimetric analysis were employed to microscopically investigate how this process parameter impacts mechanical performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.607-612
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• 2017

Recently, additive manufacturing (AM) technology, also known as 3D printing technology, has attracted attention as an innovative production method to fabricate functional components having complex shapes with saving materials. In particular, a fabrication of poly lactic acid (PLA) parts through a fused deposition modeling (FDM) technique has attracted much attention in the medical field. In this paper, an experimental study on the identification of dominant process parameters influencing mechanical properties of PLA parts fabricated by the FDM process is conducted, and their optimal values for maximizing the mechanical properties are obtained. Three process parameters are considered in this research, namely, layer thickness, a part orientation and in-fill. It is known that thin layer thickness, part orientation diagonal to the tension direction, and full in-fill are optimal conditions to maximize the mechanical properties.

• Tunnel and Underground Space
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• v.26 no.6
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• pp.516-523
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• 2016

Roughness of a joint surface is one of the most important parameters that affects the mechanical and hydraulic behavior of rock mass. Therefore, various studies on making constitutive model and/or roughness quantification have been conducted in experimental and empirical manners. Advances in recent 3D printing technology can be utilized to generate a joint surface with a specific roughness. In this study, a reliable technique to generate a rough joint surface was introduced and its quantitative assessment was made. Random midpoint displacement method was applied to generate a joint surface and the distribution of $Z_2$ was investigated to assess its roughness. As a result, a certain roughness can be embodied by controlling input parameters and furthermore it was able to generate a joint surface with specific roughness anisotropy.