• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.4
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• pp.166-169
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• 2001

6H-SiC bulk crystals were grown by sublimation method with different conditions in term of gaseous pressures ad source temperatures. In order to optimize the growth rate, pressure at growth period and source and substrate temperatures were investigated as experimental variables. the results were compared with each other and finally the optimum growth conditions were discussed. Furthermore the relation of the growth steps and defects formation was evaluates in the point of reducing the micropipes. Subsequently the growth steps and defects formation was evaluated in the point of reducing the micropipes. Subsequently the growth steps were observed leading to the lower step height with the lower growth rate.

• Applied Science and Convergence Technology
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• v.23 no.4
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• pp.179-186
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• 2014

Fluid model based numerical simulation was carried out for an inductively coupled plasma assisted sputter deposition system. Power absorption, electron temperature and density distribution was modeled with drift diffusion approximation. Effect of an electrically conducting substrate was analyzed and showed confined plasma below the substrate. Part of the plasma was leaked around the substrate edge. Comparison between the quasi-neutrality based compact model and Poisson equation resolved model showed more broadened profile in inductively coupled plasma power absorption than quasi-neutrality case, but very similar Ar ion number density profile. Electric potential was calculated to be in the range of 50 V between a Cr rod source and a conductive substrate. A new model including Cr sputtering by Ar+was developed and used in simulating Cr deposition process. Cr was modeled to be ionized by direct electron impact and showed narrower distribution than Ar ions.

• Journal of the Korean Graphic Arts Communication Society
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• v.25 no.1
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• pp.81-94
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• 2007

Recently, the trend in the printing industry includes shorter run lengths and with fast turnaround times. As new markets have made it possible to produce small quantities of high-quality color products at affordable price, the general commercial printing meets the customer's diverse demand by using spot color besides process four colors. Especially, by using spot color for printing the enterprise's logo or specific color, we can see the effect of printing is getting better. With the combination of the right software, ink, media, and device can be treated as a digital proofer for spot color printing, providing significant time and cost savings compared to conventional procedures. The objective of this study is to investigate the quality of spot color proofs printed by ink-jet and dye sublimation proofer using ICC-based color management system. An Epson Stylus Color 3000 ink-jet proofer combined with Best Color Proof XXL RIP was tested for glossy and matte paper. 3M Rainbow dye sublimation proofer was examined using 3M Rainbow controller ver. 4.1 RIP on the manufacturer recommended proofing paper. ICC profiles were generated for each device using ECI 2002 visual target and evaluated for the accuracy of process 4 color reproduction. The test charts consisting of Pantone color 1140 was selected to test the quality of spot color reproduction.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.4
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• pp.344-349
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• 2006

A sublimation epitaxial method, referred to as the Closed Space Technique (CST) was adopted to produce thick SiC epitaxial layers for power device applications. We aimed to systematically investigate the dependence of SiC epilayer quality and growth rate during the sublimation growth using the CST method on various process parameters such as the growth temperature and working pressure. The etched surface of a SiC epitaxial layer grown with low growth rate $(30{\mu}m/h)$ exhibited low etch pit density (EPD) of ${\sim}2000/cm^2$ and a low micropipe density (MPD) of $2/cm^2$. The etched surface of a SiC epitaxial layer grown with high growth rate (above $100{\mu}m/h$) contained a high EPD of ${\sim}3500/cm^2$ and a high MPD of ${\sim}500/cm^2$, which indicates that high growth rate aids the formation of dislocations and micropipes in the epitaxial layer. We also investigated the Schottky barrier diode (SBD) characteristics including a carrier density and depletion layer for Ni/SiC structure and finally proposed a MESFET device fabricated by using selective epilayer process.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.1
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• pp.44-49
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• 1995

Abstract The surface of 6H - SiC bulk crystal grown by sublimation process was investigated by optical microscope observation. Since, in the 6H crystal growing, the crystal had the habitual step growth attitude such that the lateral growth rate along the random a - axis orientation was higher than that along the c - axis of the growth direction, then many steps were developed. There were, also, many micropipes on the surface in the form of as-like large voids. However, they were differenciated with pores and cross- sectional shape of them were close to the circle. In this study, many micropipes, planar defects and the growth steps appeared on the grown crystal surface were investigated.

• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.1
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• pp.79-90
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• 2002

Recently, the research about color matching for the input/output devices of printing process is progressing rapidly by the digitization. The calibration method of flatbed scanner widely used as an input device for prepress process is especially important for color proofing of high quality color prints. In this paper, scanner calibration method using 3-dimensional look-up table and tetrahedral interpolation was examined and analysed comparatively on the three kinds of original copies, such as photograph, dye sublimation proof and ink jet print for IT8.T/2 target.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.796-799
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• 2002

BSCCO thin films are fabricated via a co-deposition process at an ultra-low growth rate using ion beam sputtering. The sticking coefficient of Bi element exhibits a characteristic temperature dependence. This temperature dependence of the sticking coefficient was explained consistently on the basis of the evaporation and sublimation processes of Bi$_2$O$_3$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.7
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• pp.673-679
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• 2006

A sublimation method using the SiC seed crystal and SiC powder as the source material is commonly adopted to grow SiC bulk single crystal. However, it has proved to be difficult to achieve the high quality crystal and the process reliability because SiC single crystal should be grown at very high temperature in closed system. In this study, SiC crystal boules were prepared with different angles in trapezoid-shaped graphite seed holders using sublimation physical vapor transport technique (PVT) and then their crystal quality was systematically investigated. The temperature distribution in the growth system and the crystal shape were varied with angles in trapezoid-shaped graphite seed holders, which was successfully simulated using 'Virtual Reactor'. The SiC polytype proved to be the n-type 6H-SiC from the typical absorption spectrum of SiC crystal. The micropipe densities of SiC wafers in this study were measured to be < $100/cm^2$. Consequently, SiC single crystal with large diameter was successfully achieved with changing angle in trapezoid-shaped graphite seed holders.

• Food Science of Animal Resources
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• v.28 no.3
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• pp.312-318
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• 2008

The objective of this study was to investigate the changes in ice dendrite size during freezing process in gelatin matrix as a model food system in order to provide mathematical relation between freezing condition and ice dendrite size. Gelatin gel as a model matrix was frozen in unidirectional Neumann's type of heat transfer. The thermograms' analysis allowed to determine the freezing temperature of the sample, the position of the freezing front versus time, and thus, freezing front rate. The morphology of ice dendrites was observed by scanning electron microscopy after freeze-drying. We observed that the means size of ice dendrite increased with the distance to the cooling plate; however, it decreased with the cooling rate and the cooling temperature. In addition, the shorter durations of the freeze-drying process was shorter decreeing the decreased the freezing front rate, resulted in their resulting in a larger pore size of the ice dendrite pores for the sublimation channel of that operate as water vapor sublimation channels. From these results, we could derive a linear regression as an empirical mathematical model equation between the ice dendrite size and the inverse of freezing front rate.

• Journal of the Korea Fashion and Costume Design Association
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• v.19 no.2
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• pp.39-48
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• 2017

Transfer printing is a method to combine printing and dyeing technology by the use of sublimation. It is an environmentally-friendly printing method that saves costs, reduces the production processes by the omission of the washing process, and saves time by maintaining quality. Due to the development of transfer printing, a high value added printing technology is available now but color fastness to sublimation of the printing products is still low since there are few dyes that have an affinity to the fabrics and the application technology is still inadequate. Specially, in case of high concentration black dyes, eco-label type black dyes, which is a substitution for general dispersal dyes, have been developed while general dispersal black dyes are still used, creating issues such as color differences on the surface and back side of the fabrics and contamination by friction after transfer printing. There are also some restricted substances such as allergens. To address these issues, high concentration black dyes and application technology that are environmentally-friendly and that have over 16 K/S through the use of single dyes with excellent color fastness, fixation ability, and similar melting temperature were developed for this study.