• 한국지역사회생활과학회지
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• 제28권1호
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• pp.143-154
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• 2017

This study was conducted to develop fabrics using non-toxic and eco-friendly natural dyes made from curcuma and coffee extract. The natural dyes were applied to non-printed cotton fabrics using the dip dyeing method, and the pattern was hand-printed onto the dyed fabrics to make dyed printed-fabrics. The four types of developed fabric samples were compared to analyze the effects of the dyeing materials and printing on the hygienic properties of curcuma- and coffee-dyed fabrics. The findings were as follows. First, air permeability of both curcuma- and coffee-dyed fabrics was greatly affected by the presence of patterns, although the type of dye did not seem to have an effect. Printing greatly reduced air permeability of the fabric, and coffee-dyed fabric showed greater reduction of dyeing method than curcuma-dyed fabric. Moisture regain also tended to decrease with printing, but the change was much smaller compared to air permeability. Second, increased UV blockage was observed in curcuma- and coffee-dyed fabrics with patterns compared to non-printed fabrics, showing that printing enhanced UV blocking. Third, deodorization rate tended to increase sharply for both curcuma- and coffee-dyed fabrics until 30 minutes and gradually increased thereafter to yield 30% for curcuma and 50% for coffee at 120 minutes, demonstrating higher deodorization of coffee dye. Coffee-dyed fabric showed an antibacterial rate about twice as high as that of curcuma-dyed fabric, and the observed data suggest that curcuma-dyed fabric had an insignificant level of antibiosis. Fourth, printing significantly enhanced wash, sunlight, and compound colorfastness of the two types of dyed fabrics. The effect of printing was most dramatic on sunlight and compound colorfastness, which are aspects in which natural dyed fabrics perform poorly in general. Eventually, the development and application of biologically- and environmentally-friendly fabrics with natural dyes correspond with increased interest towards the wellness and healthy attitudes of modern society.

• 한국인쇄학회지
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• 제25권2호
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• pp.85-93
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• 2007

The printed mottle is recognized as the most common printing problems in using coated paper and one of the most difficult problems to solve in offset printing. Printed mottle is caused by an uneven penetration of ink into the paper and binder migration. The prevention of printed mottle requires of coating color formation, especially the minimum of binder migration. Printing worked by interaction of printing ink, coated paper and printing pressure. In this study, we investigated the effect of the properties changing of coated paper and printing conditions such as ink dispersion, nip condition and amount of ink transfer.

• 한국인쇄학회지
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• 제21권2호
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• pp.31-42
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• 2003

The optimum color proofing system with the similar colorants to the printing system has to be used in high quality offset color printing. And so, the evaluation on color reproduction properties of the colorants for proofer and press are very important. In this paper, the optimum color proofing method is recommended by means of colorimeric comparative evaluation on the color reproduction properties such as color gamut, color difference, hue error of the colorants for the proofing system of CRT monitor, inkjet printer, dye sublimation type digital proofer, and the actual printing system of offset press.

• 한국인쇄학회지
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• 제12권1호
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• pp.145-157
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• 1994

Litho printing ink vehicles based on rosin modified phenolic are faster drying, have better durability, are harder and glosser and have greater resistance to water than ones based on ester gums. Ink-Water balance and rheological properties are important in litho printing process. These physical properties is concerned with molecular weight of Resin to use vehicle. So this paper was studied about the effects of changing molecular weight of Rosin modified phenolic on surface tension, viscosity, pseudoplasticity and printability of Litho Inks. The results were as follows. 1) The surface tension of model inks depended on the molecular \veight of the resin : Dispersion componnent of ink increase but non dispersion component decrease as molecular weight of Resin increase. 2) Water pick-up of litho ink is more fast balance, using low molecular weight of Resin. 3) Viscosity, Yield value and Newtonian value of model inks increase as molecular weight of Resin increase. 4) The litho ink prepared with the modified phenolic of which molecular weight is about 20000 showed the highest printing density and gloss.

• 센서학회지
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• 제30권4호
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• pp.218-222
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• 2021

Wearable multi-sensors based on nanocrystals have attracted significant attention, and studies on patterning technology to implement such multi-sensors are underway. Conventional patterning processes may affect material properties based on high temperatures and harsh chemical conditions. In this study, we developed an inkjet printing technique that can overcome these drawbacks through the application of patterning processes at room temperature and atmospheric pressure. Nanocrystal-based ink is used to adjust properties efficiently. Additionally, the viscosity and surface tension of the solvents are investigated and optimized to increase patterning performance. In the patterning process, the electrical, electrothermal, and electromechanical properties of the nanocrystal pattern are controlled by the ligand exchange process. Experimental results demonstrate that a multi-sensor with a temperature coefficient of resistance of 3.82 × 10^-3 K^-1 and gauge factor of 30.6 can be successfully fabricated using one-step inkjet printing.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.545-548
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• 2002

$(Ba_{0.6-x}Sr_{0.4}Ca_x)TiO_3$(BSCT) (x=0.10, 0.15, 0.20) powders were prepared by the sol-gel method and BSCT thick films were fabricated by the screen-printing method. The structural properties as a faction of the composition ratio were studied. As a result of the differential thermal analysis (DTA), exothermic perk was observed at around $860^{\circ}C$ dne to the formation of the polycrystalline perovskite phase. The BSCT thick films sintered at $1350^{\circ}C$ for 2h showed the average grain size of $2{\sim}7{\mu}m$. The average thickness of BSCT thick films, obtained by 3 times of screen-printing, was approximately $85{\mu}m$.

• 한국인쇄학회지
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• 제24권2호
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• pp.25-33
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• 2006

The reality of domestic prints neither possesses an objective standard of standard density nor a spectrophotometric method in regard to process ink. As a result, it creates a difficult communication between a designer and a Prepresser as to estimating the color of reproduction prints. There was an experiment on paper, ink, and printing company to obtain the standard point. The result shows that paper has minimum effect on color reproduction as opposed to ink and different printing companies, which had a great effect. The purpose of this paper is to confirm how different the color reproduction properties of prints are using densitometer and spectrophotometer for three different ink companies. The process color inks of three different companies were used under the same printing environment in this experiment.

• 한국기계가공학회지
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• 제20권8호
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• pp.52-59
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• 2021

In this study, we experimentally evaluated the mechanical properties and geometric form accuracy in FDM 3D printing processes based on the printing direction, building direction, and layer thickness. The specimen test results showed that the tensile strength increased by over 33% in the printing direction compared to the direction perpendicular to printing and the tensile strength becomes larger as the layer thickness decreased. Furthermore, the tensile and impact strengths in the building direction were significantly reduced due to the difference in the interlayer joining and bonding strengths of the fused material. Additionally, shrinkage of the material due to phase change induced curl distortion especially in thin and long 3D-printed products, which increased as the layer thickness increased.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.651-653
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• 2008

In this paper, we report electrical properties of OTFTs by using ink-jet printing with polyvinylphenol (PVP) for gate insulator and bis(triisopropylsilylenthynyl) pentacene (TIPS pentacene) for semiconductor. OTFTs produced the excellent performance with the mobility of $1.27\;cm^2/V.s$ for top contact structure(TCS) and inverter consisting of two OTFTs exhibited the gain of 6.75.

• 한국초전도ㆍ저온공학회논문지
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• 제26권2호
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• pp.19-23
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• 2024

3D printing has the advantage of being able to process various types of parts by layering materials. In addition to these advantages, 3D printing technology allows models to be processed quickly without any special work that can be used in different fields to produce workpieces for various purposes and shapes. This paper deals to not only increase the utilization of 3D printing technology, but also to revitalize 3D printing technology in applications that require similar cryogenic environments. The goal of this study is to identify the mechanical properties of polylactic acid and photopolymer resin processed by Fused Deposition Modeling (FDM) and Digital Light Processing (DLP) respectively. The entire process is meticulously examined, starting from getting the thermal contraction using an extensometer. A uniaxial tensile test is employed, which enables to obtain the mechanical properties of the samples at both room temperature (RT) and cryogenic temperature of 77 K. As the results, photopolymer resin exhibited higher tensile properties than polylactic acid at RT. However, at cryogenic temperatures (77 K), the photopolymer resin became brittle and failure occurred due to thermal contraction, while polylactic acid demonstrated superior tensile properties. Therefore, polylactic acid is more suitable for lower temperatures.