• 펄프종이기술
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• 제47권5호
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• pp.134-140
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• 2015

This study was carried out to evaluate whether EVAc, acryl latex and biobinder could substitute the part of SB latex for pre-coating color formula or not. Different coating colors prepared through the substitution of 30% SB latex with EVAc, acryl latex, and biobinder were applied for pre-coating layer. 100% SB latex is used as a binder for top coating color. The optical properties, gloss, roughness, stiffness, dry- and wet-pick strength were measured. There were no significant differences in the brightness, whiteness, opacity, roughness, ink set-off and gloss of paper coated with 5 different coating colors. However the stiffness, dry- and wet-pick strength were somewhat lower than those of conventional coating color which 100% SB latex was used as a binder. Although the part of SB latex could be substituted with EVAc, acryl latex and biobinder without sacrificing the qualities of coated paper. Further researches on the improvement of stiffness, dry- and wet-pick strength, and the optimization of rheology of coating color in order to improve the qualities of coated paper are strongly recommended.

• 한국인쇄학회지
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• 제8권1호
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• pp.1-20
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• 1990

$\alpha$,$\beta$,$\varepsilon$ type copper phthalocy $\alpha$,$\beta$,$\varepsilon$ type copper phthalocyanine(CuPc) pigment was purified by a simple train sublimation technique. The layered photoconductor was made with $\varepsilon$ type CuPc as a carrier generation layer(CGL) and polyvinly carvazol(PVCz) as a carrier transport layer(CLT). A CGL of CuPc was electrochemical deposited on an Al substrate used as cathode in pigment dispersion solutions. a CTL of PVCz pwas spin coated on $\varepsilon$ type CuPc thin film by a spin coater. The effect of sonication time, electrophotographic property of the layered photoconductor were studied with surface coverage, surface potential and sensitivity.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.86-88
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• 2008

Organosiloxane based spin on planarizing dielectrics (PTS-E and PTS-R) were developed for application in flat panel displays as a replacement to conformal chemical vapor deposited SiNx. Here we demonstrate the successful use of siloxane-based material as a passivation layer for active matrix $\alpha$-Si thin film transistors (TFT) on both rigid and flexible substrates.

• Journal of Information Display
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• 제12권4호
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• pp.213-217
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• 2011

Printing technologies were applied to fabricate a flexible organic thin-film transistor (OTFT) backplane for electrophoretic displays (EPDs). Various printing processes were adopted to maximize the figures of each layer of OTFT: screen printing combined with reverse offset printing for the gate electrodes and scan bus lines with Ag ink, inkjet for the source/drain electrodes with glycerol-doped Poly (3,4-ethylenedioxythiophene): Poly (styrenesulfonate) (PEDOT:PSS), inkjet for the semiconductor layer with Triisopropylsilylethynyl (TIPS)-pentacene, and screen printing for the pixel electrodes with Ag paste. A mobility of $0.44cm^2/V$ s was obtained, with an average standard deviation of 20%, from the 36 OTFTs taken from different backplane locations, which indicates high uniformity. An EPD laminated on an OTFT backplane with $190{\times}152$ pixels on an 8-in panel was successfully operated by displaying some patterns.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1448-1449
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• 2008

Inkjet printing is commonly used in depositing the solution of functional materials on the specific locations of a substrate, and also it can provide easy and fast patterning of polymer films over a large area. Inkjet printing is applicable to fabricating an organic light emitting diode (OLED), since conducting materials used as emissive electroluminescent layers can be manufactured into inks for ink jetting. By using the inkjet technology, we have succeeded in patterning a poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) layer and a poly[2-Methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) layer on the Indume tin oxide (ITO) patterned substrates, and fabricating organic light emitting diodes.

• Journal of Photoscience
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• 제5권2호
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• pp.63-67
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• 1998

New photoinitiator systems of dimethylphenacylsulfonium butyltnphenylborate (DMPSB) as a donor-acceptor initiator and styryl dyes have been investigated for free radical polymerization of an acrylate with visible lasers (488, 514 and 647 nm). DMPSB was able to be sensitized by many styryl dyes. When polymerized with pentaerythrithol triacrylate, the sensitivity value of the photosensitive layer containing DMPSB was higher than that of an tetrabutylammonium butyltnphenylborate (TBAB) as an electron donating initiator or a dimethylphenacylsulfonium tetrafiuoroborate (DMPS) as an electron accepting initiator. The sensitivity values of the photosensitive layer containing the photoinitiator systems had a close relation to the free energy changes between the excited singlet styryl dyes and DMPSB.

• 한국대기환경학회지
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• 제12권4호
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• pp.459-472
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• 1996

An experimental investigation on the wind flow over smooth bell-shaped two-dimensional hills with hill slopes (the ratio of height to half width) of 0.3 and 0.5 is performed in an atmospheric boundary-layer wind tunnel. Two categories of the models are used in the present investigation; six two-dimensional single-hills, and four continuous double-hills. The measurements of the flow field and surface static-pressure distribution are carried out over the Reynolds number (based on the hill height) of 1.9 $\times 10^4, 3.3 \times 10^4, and 5.6 \times 10^4$. The velocity profiles and turbulence characteristics are measured by the pitot-tube and X-type hot-wire anemometer, respectively. The undisturbed boundary-layer profile on the bottom surface of the wind tunnel is reasonably consistent with the power-law profile with $\alpha = 7.0 (1/\alpha$ is the power-law exponent) and shows good spanwise uniformities. The profiles of turbulent intensity are found to be consistent along the centerline of the wind tunnel. The measured non-dimensional speed-up profiles at the hill crest show good agreements with the predictions of Jackson and Hunt's linear theory. The flow separation occurs in the hill slope of 0.5, and the oil-ink dot method is used to find the reattachment points in the leeside of the hill. The measured reattachment points are compared with the numerical predictions. Comparisons of the mean velocity profiles and surface pressure distributions between the numerical predictions and the experimental results show good agreements.

• Korean Journal of Chemical Engineering
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• 제35권12호
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• pp.2430-2441
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• 2018

Selenium (Se)-rich binary Cu-Se and In-Se nanoparticles (NPs) were synthesized by a modified heat-up method at low temperature ($110^{\circ}C$) using the gum exudates from a cherry blossom tree. Coating of CISe absorber layer was carried out using Se-rich binary Cu-Se and In-Se NPs ink without the use of any external binder. Our results indicated that the gum used in the synthesis played beneficial roles such as reducing and capping agent. In addition, the gum also served as a natural binder in the coating of CISe absorber layer. The CISe absorber layer was integrated into the solar cell, which showed a power conversion efficiency (PCE) of 0.37%. The possible reasons for low PCE of the present solar cells and the steps needed for further improvement of PCE were discussed. Although the obtained PCE is low, the present strategy opens a new path for the fabrication of eco-friendly CISe NPs solar cell by a relatively chief non-vacuum method.

• 펄프종이기술
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• 제40권5호
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• pp.60-69
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• 2008

The principal reasons for applying a pigment coating to paper are to improve appearance and printability. The pigment coating provides a surface that is more uniform and more receptive to printing ink than are the uncoated fibers and, in turn, both facilitates the printing process and enhances the graphic reproduction. The improvement in print quality is readily apparent, especially in image areas or when multiple colors are involved. Although pigment coating of paper is to improve the printability, coated paper is not completely free from printing defects. Actually there are a number printing defects that are observed only with the coated papers. Among the printing defects that are commonly observed for coated papers, print mottle during multi-color offset printing is one of the most concerned defects, and it appears not only on solid tone area but also half dot print area. There are four main causes of print mottle ranging from printing inks, dampening solution, paper, and printing press or its operation. These indicates that almost every factors associated with lithographic printing can cause print mottle. Among these variation of paper quality influences most significantly on print mottle problems in multicolor offset printing, and this indicates that paper is most often to be blamed for its product deficiency as far as print mottle problems are concerned. Furthermore, most of the print mottle problems associated with paper is observed when coated papers are printed. Uncoated papers rarely show mottling problems. This indicates that print mottle is the most serious quality problems of coated paper products. Overcoming the print mottle is becoming more difficult because the operating speeds of coating and printing machines are increasing, coating weights are decreasing, and the demands on high-quality printing are increasing. Print mottle in offset printing is caused by (a) nonuniform back trap of ink caused by a nonuniform rate of ink drying, referred as "back trap mottle, and (b) nonuniform absorption of the dampening solution. Furthermore, both forms of print mottle have some relationship to the structure of the coated layer. The surest way of eliminating ink mottling is to eliminate unevenness in the base paper. Coating solutions, often easier to put into practice, should, however, be considered. In this paper the principal factors influencing print mottle of coated papers will be discussed. Especially the importance of base paper roughness, binder migration, even consolidation of coating layers, control of the drying rate, types of binders, etc. will be described.

• 한국군사과학기술학회지
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• 제6권4호
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• pp.124-131
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• 2003

When a secondary gaseous flow is injected vertically into a supersonic flow through circular nozzle, a complicated structure of flow field is produced around the injection area. The interaction between the two streams produces a strong bow shock wane on the upstream side of the side-jet. The results show that bow shock wave and turbulent boundary layer interaction induces the boundary layer separation in front of the side-jet. This study is to analyze the structure of flow fields and distribution of surface pressure on the flat plate according to total pressure ratio using a supersonic cold-flow system and also to study the control force of affected side-jet. The nozzle of main flow was designed to have Mach 2.88 at the exit. The injector has a sonic nozzle with 4mm diameter at the exit of the side-jet. In experiments, The oil flow visualization using a silicone oil and ink was conducted in order to analyze the structure of flow fields around the side-jet. The flow fields are visualized using the schlieren method. In this study, a computational fluid dynamic solution is also compared with experimental results.