• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.6
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• pp.99-104
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• 2019

In the present study is focused on the evaluation of the shrinkage characteristics of mix proportion using viscosity agent for printing. Also, another purpose is to compare the shrinkage properties of the mold cast specimen with the additive manufactured specimen using 3D printing techniques. Viscosity agent makes the shrinkage was reduced by an average of 25% (as of 56 days) compared to the reference mix. The effects of reduced shrinkage were also founded, with a reduction of about 15% (as of 28 days).As a result of evaluating the shrinkage using the additive manufactured specimen and the mold cast specimen prepared by the printing mix, the shrinkage of the additive manufactured specimen was reduced by about 25% (based on 28 days). Based on the results of this study, it is possible to predict the shrinkage rate and the occurrence of cracks due to shrinkage on the printing of cement-based composite materials using 3D printing.

• Journal of Fashion Business
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• v.20 no.1
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• pp.98-114
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• 2016

This research study was performed to compare between Korean traditional color and digital transfer textile printing. This would help to find the new direction to apply Korean traditional colors to modern textile industry. The objective of this study is to digitalize Korean traditional colors to be applied to modern textiles, based on research studies by previous researchers, on the actualization of Korean traditional colors for textiles. The study focused on 21 red colors among others. Digital color palette of graphic program was printed on 6 different polyester textiles by using digital transfer textile printing. Different things to be supplemented were found by comparing the results with the colors of Korean traditional standard color names. After measuring the colors, Munsell color system and CIE $L^*a^*b^*$ value were measured then comparative study was performed on the measured values using 3D graphs. Measured colors of Munsell varied by color but in overall, chroma became low while brightness became high. Color characteristic of warm colors got weakened by turning into cold colors as brightness got high but yellow and red got low due to the characteristics of CIE $L^*a^*b^*$ value. This study has limitations with color analysis of digital transfer textile printing due to standardization of textiles and standardization of traditional colors however it can support to actualize the colors for the design using traditional color names by visualizing the color change of digital transfer textile printing in the future.

• Journal of the Korean Graphic Arts Communication Society
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• v.31 no.1
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• pp.65-78
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• 2013

In gravure printing ink in printed flexible packaging considering the characteristics of the study more accurate color management options and results were as follows. When applying G7 calibration, P2P of the target GRACol G7 evaluate the delta $L^*$ and delta $F^*$, CMY and K-scale average of the results of delta $L^*$ and the highest tolerance G7 average of 1.5 and 3.0 are included in all the best. In addition, the average delta $F^*$ and super delta $F^*$, G7 tolerance by being included within the scope of color management, G7 calibration was possible. Target IT 8.7/4 CMYK, when applied to the calibration G7, Color gravure printing machine is applied to the average of the previous decreased from 12.4 to 3.6. In addition, if a digital proof is EPSON WT 7900 the average color applied to the previous reduction from 5.24 to 0.74 because of the gravure printing color proofing system was effective in the management. G7 calibration by applying the reference print profile of the Epson WT 7900-G-icc, the average was 0.74 coloration, and gravure-G-icc cases, the average color of the 3.60 per GRACol average of all the five colors below were included within the allowable range. Thus, the flexible packaging gravure printing color management of printed after applying the first G7 calibration, the results refer to the press by the profiling, and where best to take advantage of the profile creation was good.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.873-876
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• 2000

Characteristics of piezoelectric thick films prepared by screen printing method were investigated. The piezoelectric thick films were printed using Pb(Mg,Nb)O$_3$-Pb(Zr,Ti)O$_3$system. The lower electrodes were coated with various thickness of Ag-Pd by screen printing to investigate the effect as a diffusion barrier and deposited with Pt by sputtering on Ag-Pd. The ceramic paste was prepared by mixing powder and binder with various ratios using three roll miller. The fabricated thick films were burned out at 650$^{\circ}C$ and sintered at 950$^{\circ}C$ in the O$_2$condition for each 20, 60min after printing with 350mesh screen. The thickness of piezoelectric thick film was 15∼20 $\mu\textrm{m}$ and the Ag-Pd electrode acted as a diffusion barrier above 3 $\mu\textrm{m}$ thickness. When the lower electrode Ag-Pd was 6 $\mu\textrm{m}$ and the piezoelectric thick films were sintered by 2nd step (650$^{\circ}C$/20min and 950$^{\circ}C$/1h) using paste mixed Pb(Mg,Nb)O$_3$-Pb(Zr,Ti)O$_3$$.$ MnO$_2$+ Bi$_2$O$_3$. V$_2$O$\_$5/ and binder in the ratio of 70:30, the remnant polarization of thick film was 9.1 ${\mu}$C /cm$^2$.

• Journal of radiological science and technology
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• v.44 no.4
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• pp.343-350
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• 2021

3D printing technology is an additive manufacturing technology produced through 3D scanning or modeling method. This technology can be produced in a short time without mold, which has recently been applied in earnest in various fields. In the medical field, 3D printing technology is used in various fields of radiology and radiation therapy, but related research is insufficient in the field of nuclear medicine. In this study, we compare the characteristics of traditional nuclear medicine phantom with 3D printing technology and evaluate its applicability in clinical trials. We manufactured the same size phantom of poly methyl meta acrylate(PMMA) and acrylonitrile butadiene styrene(ABS) based on the aluminum step wedge. We used BrightView XCT(Philips Health Care, Cleveland, USA) SPECT/CT. We acquired 60 min list mode for Aluminum, PMMA and ABS phantoms using Rectangular Flood Phantom (Biodex, New York, USA) ^99mTcO₄ 3 mCi(111 MBq), 6 mCi (222MBq) and ⁵⁷Co Flood phantom(adq, New Hampshire, USA). For the analysis of acquired images, the region of interest(ROI) were drawn and evaluated step by step for each phantom. Depending on the type of radioisotope and radiation dose, the counts of the ABS phantom was similar to that of the PMMA phantom. And as the step thickness increased, the counts decreased linearly. When comparing the linear attenuation coefficient of Aluminum, PMMA and ABS phantom, the linear attenuation coefficient of the aluminium phantom was higher than that of the others, and the PMMA and ABS phantom had similar the linear attenuation coefficient. Based on ABS phantom manufactured by 3D printing technology, as the thickness of the PMMA phantom increased, the counts and linear attenuation coefficient decreased linearly. It has been confirmed that ABS phantom is applicable in the clinical field of nuclear medicine. If the calibration factor is applied through further research, it is believed that practical application will be possible.

• Journal of Powder Materials
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• v.31 no.2
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• pp.119-125
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• 2024

The n-type Bi_2-xSb_xTe₃ compounds have been of great interest due to its potential to achieve a high thermoelectric performance, comparable to that of p-type Bi_2-xSb_xTe₃. However, a comprehensive understanding on the thermoelectric properties remains lacking. Here, we investigate the thermoelectric transport properties and band characteristics of n-type Bi_2-xSb_xTe₃ (x = 0.1 - 1.1) based on experimental and theoretical considerations. We find that the higher power factor at lower Sb content results from the optimized balance between the density of state effective mass and nondegenerate mobility. Additionally, a higher carrier concentration at lower x suppresses bipolar conduction, thereby reducing thermal conductivity at elevated temperatures. Consequently, the highest zT of ~ 0.5 is observed at 450 K for x = 0.1 and, according to the single parabolic band model, it could be further improved by ~70 % through carrier concentration tuning.

• International Journal of Costume and Fashion
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• v.6 no.1
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• pp.56-70
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• 2006

The purpose of this study was to develop the high-value-added fashion cultural products with Korean image for the enhancement of global competitiveness. For this purpose, theoretical examination of the unique beauty of Korea and Korean image was first performed. Especially, characteristics of Korean traditional botanic patterns were investigated with LOHAS(Lifestyles of Health and Sustainability) philosophy which is the focus of the current design trend. Along with the above, the environmentally-friendly digital textile printing technology and Korean traditional botanic patterns were used to produce creative and globally-competitive fashion cultural products. Finally, a series of fashion cultural products were developed such as table runner, table mat and bedclothes.

• Journal of the Korean Graphic Arts Communication Society
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• v.28 no.1
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• pp.65-75
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• 2010

Environmentally friendly, stencil and screen printing for cost-effective for maskless. In this study, UV -LED light source for the dispersion characteristics and high competence photoresist coating was prepared. Wavelength of 365nm UV-LED exposure device using the maskless lithography, 1.7kgf/$cm^2$ $2600mmH_2O$ the injection pressure and the suction pressure by using a dry photoconductor symptoms were dry emulsion on the market as a result, curing properties and adhesion, hardness, solvent resistance and excellent reproduction of fine patterns and ecological stencil technology was available and could be confirmed as a possibility.

• Journal of the Korean Graphic Arts Communication Society
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• v.12 no.1
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• pp.13-27
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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 printablility of Litho Inks. The results were as follows. 1) The surface tension of model inks depended on the molecular weight 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.

• Journal of the Korean Graphic Arts Communication Society
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• v.14 no.2
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• pp.101-113
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• 1996

In general, printing inks are mainly composed of pigments and vehicles. Its characteristics are affected, to a greater or lesser extent, by the size and distribution of the pigment particles in the dispersion. Color strength, transparency and gloss generally increases with an decrease in particle size of pigments. On the contrary, opacity, lightfastness tend to increases with an increase in particle size of pigments In this work, we have investigated an effect of surface area of pigments on the physical properties of printing of printing ink which made up vehicles for sheet fed and organic pigment Lake Red C(C.I.Pigment Red 53:1) that different surface area and particle size. It was found that gloss, tack and yield value increases with an increase in surface are of pigments, but grindness is reduced.