• Journal of the Korean Society for Precision Engineering
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• v.27 no.3
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• pp.95-103
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• 2010

Roll to Roll (R2R) is one of the most promising production technologies in the printed electronics such as OLEDs, e-paper, backplanes, RFID because this technology can save production cost and increase production speed. Printed electronics includes various processes such as printing, drying, winding, unwinding, and so on. In printed electronics R2R system, air-flotation oven is employed for drying process. Therefore, it is essential to introduce efficient and fast drying process when printing is finished. This paper considers the analysis of drying process in R2R that involves hot air flow. Air-flotation oven consists of non-contact supports and drying of coated web materials such as plastic films and paper. In this paper, experimental results and numerical analysis of pressure-pad air bar are investigated. The aerodynamic characteristics of pressure-pad air bar are numerically calculated using computational fluid dynamics (CFD) approach. Then the measured values of the aerodynamic forces for air bars are compared with those of CFD analysis.

• Korean Journal of Materials Research
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• v.22 no.9
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• pp.476-481
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• 2012

Among the various roll-to-roll printing technologies such as gravure, gravure-offset, and reverse offset printing, reverse offset printing has the advantage of fine patterning, with less than 5 ${\mu}m$ line width. However, it involves complex processes, consisting of 1) the coating process, 2) the off process, 3) the patterning process, and 4) the set process of the ink. Each process demands various ink properties, including viscosity, surface tension, stickiness, and adhesion with substrate or clich$\acute{e}$; these properties are critical factors for the printing quality of fine patterning. In this study, Ag nano ink was developed for reverse offset printing and the effect of polyvinylpyrrolidone(PVP), used as a capping agent of Ag nano particles, on the printing quality was investigated. Ag nano particles with a diameter of ~60 nm were synthesized using the conventional polyol synthesis process. Ethanol and ethylene glycol monopropyl ether(EGPE) were used together as the main solvent in order to control the drying and absorption of the solvents during the printing process. The rheological behavior, especially ink adhesion and stickiness, was controlled with washing processes that have an effect on the offset process and that played a critical role in the fine patterning. The electrical and thermal behaviors were analyzed according to the content of PVP in the Ag ink. Finally, an Ag mesh pattern with a line width of 10 ${\mu}m$ was printed using reverse offset printing; this printing showed an electrical resistivity of 36 ${\mu}{\Omega}{\cdot}cm$ after sintering at $200^{\circ}C$.

• Journal of Information Display
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• v.6 no.3
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• pp.12-17
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• 2005

The need for low cost, flexible, thin film transistor (TFT) display backplanes has focused attention on new processing techniques and materials. We report the development of TFT backplane technology based entirely on jet-printing, using a combination of additive and subtractive processing, to print active materials or etch masks. The technique eliminates the use of photolithography and has the potential to reduce the array manufacturing cost. The printing technique is demonstrated with both amorphous silicon and polymer semiconductor TFT arrays, and we show results of small prototype displays.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1021-1024
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• 2003

In this work, we fabricated various 2D metallic and polymeric nanopatterns with the feature resolution of sub-micrometer scale by using the method of microcontact printing ($\mu$ P) based on soft lithography. Silicon masters for the micromolding were made by e-beam lithography. Composite poly(dimethylsiloxane) (PDMS) molds were composed of a thin, hard layer supported by soft PDMS layer. Finally, monodisperse metal or polymer particles could be obtained in the prepared pattern for the application of electronic devices.

• Journal of the Korean Graphic Arts Communication Society
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• v.23 no.2
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• pp.25-43
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• 2005

Generally, machine calendering are used change of paper surface properties. During machine calendering, dry paper passes between the rolls under pressure, thereby improving the surface smoothness and gloss. These improvements make the paper better suited for printing and decreasing problems during the printing, such as delayed dry and set-off. Then we investigated newspaper properties by the changing of machine calendering condition, and relationship printability. Properties of each samples were examined in accordance with KS and TAPPI standard test method i.e, basic weight, bulk density, thickness, porosity, opacity, brightness, smoothness and roughness. IGT printability tester was used to obtain ink requirement of newspaper, printed density and set-off. Results of in this study, we have proposed the optimizes range of newspaper calendering condition. Useful optimize calendering condition was pressure 55 kN/m, temperature $130^{\circ}C$.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.920-922
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• 2009

Flexible, transparent thin-film transistor with active layers composed of carbon nanotube-based conducting ink were fabricated on a plastic substrate by ink-jet printing. The properties of the formulated conducting ink containing carbon nanotubes, a conducting polymer, and additives were characterized and optimized. The conducting ink was applied to flexible thin-film transistors using ink-jet printing.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.3
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• pp.203-210
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• 2021

With the development of package printing technology, the package has expanded from the basic function of protecting products to the marketing function through package design. Color, the visual element that composes the package design, is delivered to the consumer most quickly and effectively. As color marketing of these package designs expands, accurate color reproduction that the product wants to express is becoming more important. The color of an object is transmitted by absorption and scattering of light. Spectral reflectance refers to the intensity of light reflected by an object at different wavelengths by the spectral effect. As a result, the color of the object is expressed in various colors. Packaged printing inks have their own absorption and scattering coefficients, and the Kubelka-Munk model for color reproduction and prediction defines the relationship between these correlation coefficients through reflectance. In the Kubelka-Munk model for color reproduction and prediction, the relationship between the absorption and scattering coefficients (K/S) of printed material is predicted as the sum of the K/S values according to the mixing ratio of all color ink used. In this study, the reflectance of the measured print is reversely calculated at the mixing ratio of print ink using the Kubelka-Munk model. Through this, the relationship value of the ink-specific absorption/scattering coefficient constituting the final printed material is predicted. Delta E is derived through the predicted reflectance, and the similarity between the measured value and the predicted value is confirmed.

• Journal of the Korean Graphic Arts Communication Society
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• v.22 no.2
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• pp.163-178
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• 2004

In this study, the CIE RGB color space which was one of the most popular device-dependent application program in digital image processing was adopted to make the profile with the device information. The profile was applied to the digital image of a JPEG file format. The result was compared with the color reproduction of another digital image of a JPEG file format, which was made in the e-sRGB color space that had the color spaces allocated to each reproduced color of an image and device-independent colors. In this way it was investigated which color space was more appropriate for digital image processing for web printing and if the e-sRGB color space was good as a color management tool that didn't depend on a device in processing a digital image for web printing.

• Journal of the Korean Ceramic Society
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• v.37 no.10
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• pp.1001-1007
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• 2000

스크린 프린트법으로 MMIC(Monolithic Microwave Integrated Circuit)용 YIG 후막을 제조하였고, YIG의 조성과 프린트 조건의 변화가 다결정 $Y_{3-x}$C $a_{x}$ F $e_{5-x}$Z $r_{x}$ $O_{12}$ (x=0~0.3) 후막의 미세구조 및 자기적 특성에 미치는 영향을 고찰하였다. $Ca^{2+}$와 Z $r^{4+}$ 의 치환 첨가량이 0.2인 $Y_{2.8}$ C $a_{0.2}$F $e_{4.8}$ Z $r_{0.2}$ $O_{12}$ 조성의 paste로 제조된 YIG 후막의 경우, 포화 자화값이 최대를 나타내었으며, 강자성 공명 흡수선 폭은 최소를 나타내었다. 또한, YIG 후막의 두께 및 소결 유지시간 등의 제조조건을 제어함에 따라 치밀화 및 자기 특성이 향상됨을 확인할 수 있었다.다.다.

• Analytical Science and Technology
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• v.30 no.4
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• pp.167-173
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• 2017

In the era of the forth Industrial Revolution, open source code and open source hardware have gained much attention. In particular, 3D printing technology is expanding into the realms of classical science, technology and our daily lives. Relatedly, in the present study, we demonstrate the manufacture of a nano-LC MALDI spotter robot using 3D printing technology. The parts of the spotter robot were either made using a 3D printer or purchased as 3D printer parts from the 3D printer online market, so that anyone can make the robot without a deep knowledge of engineering or electronics, i.e., DIY (do-it-yourself) product. In the nano-LC MALDI spotter, the nano-LC eluent and MALDI matrix were mixed in a T-union and discharged from the capillary outlet. The eluent and matrix mixture could be spotted onto the movable MALDI plate. The MALDI plate was designed to translate in a two-dimensional space (xy plane), which was enabled by the movements of two stepper motors. In the paper, all computer-aided design (CAD) files for the parts and operation software are provided to help the reader manufacture their own spotter robot.