• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1215-1219
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• 2003

Light Guide Panel(LGP) is a key part of backlight unit(BLU) which transforms line-light of lamp to surface-light. Dot pattern is formed on the injected LGP surface by screen printing. This dot pattern is composed of several ten thousands micro dots of diameter 150-180$\mu\textrm{m}$ or so. The dot patterning by screen printing causes low productivity and low performance of TFT-LCD. This research develops the micromachining technology for LGP mould which could form micro dot pattern by injection molding, removing the existing screen printing process.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.74-80
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• 1999

In this study, a stereolithography apparatus (SLA) prototype is used as a master model to be transformed into the silicone pattern by vacuum tool forming. The tool for the first prototype is fabricated by using this silicone pattern. Following this procedure, a temporary tool with metal powder and epoxy for wax injection is prepared for the die set of quick change type which consists of upper and lower base die나 and an insert die. The die set of quick change type appears to be very effective in casting operation by changing tools rapidly. The original wax pattern is formed through the die set, and is made of lost-was. Finally the lost-wax pattern is applied to investment casting. The final casting product is checked regarding its dimensional accuracy.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.2
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• pp.51-57
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• 2021

The quality of the ceramic sintered coating on a metal surface through laser surface treatment is affected by the laser irradiation pattern. Depending on the laser irradiation pattern, the amount of residual stress and heat applied or accumulated on the surface increases or decreases, affecting the thickness attained in the ceramic sintering area. When the heat energy accumulated in the sintering area is high, the ceramic and the metal alloy melt and sufficiently mix to form a homogeneous and thick bonding interface. In this study, the thermal energy accumulation in the region sintered with zirconia was controlled using four types of laser processing patterns. The thickness of the diffusion region is analyzed by laser-induced breakdown spectroscopy of Mg-ZrO2 generated by laser sintering zirconia powder on the magnesium alloy surface. On the basis of the analysis of the Mg and Zr present in the sintered region through LIBS, the effect of the irradiation pattern on the sintering quality is confirmed by comparing and analyzing the heat and mass transfer tendency of the diffusion layer and the degree of diffusion according to the irradiation pattern. The derived diffusion coefficients differed by up to 9.8 times for each laser scanning pattern.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.4
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• pp.227-239
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• 2021

A practical and effective method of X-ray powder diffraction analysis was investigated for quantitative analysis of the mineral content of natural samples. Sample mounting experiments were conducted to select the best randomly oriented powder sample mount. A comparative experiment was also made between a reference intensity ratio (RIR) method, which compares a single peak intensity with standard material, and the Rietveld method, which calculates a full X-ray diffraction pattern, to search for the effective method of mineral quantification. In addition, samples containing amorphous minerals were quantitatively analyzed by the Rietveld method and the efficiency was reviewed. As a result of the study, the optimal random orientation could be reached by the side mounting method. The Rietveld method using the full pattern of X-ray diffraction was more suitable for mineral quantitative analysis, rather than the RIR method using a specific peak. However, either method could depend on the analyst's experience in addition to analytical technique. Moreover, amorphous minerals can be quantitatively analyzed by the Rietveld method, and the analysis results make the geological analysis possible.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1240-1241
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• 2008

Superconducting ceramics of YBaCuO was fabricated on SrTiO substrate by chemical fabrication method using fine powder of YBaCuO having diameter less than 1um. The pattern of the fabricated superconducting bulk was linear and the thickness of it can be controlled in the range of 50um. The structure of the surface of film by diffraction pattern and composition. The tape like YBaCuO bulk with width of 10mm was formed on substrate using similar method. Tape like film is expected to utilize as material of superconducting tape.

• Journal of Powder Materials
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• v.18 no.4
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• pp.322-326
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• 2011

Inkjet printing was successfully done using Cu nano powder ink after these Cu nano powders were dry-coated with 1-octanethiol for oxidation prevention. 1-octanethiol, which is Self-Assembled Multi-layers (SAMs), was coated approximately 10-nm thick on the surface of Cu nano powders. 1-Octanol, which has the same chain length as that for 1-octanethiol, was used as a solvent to make the ink for inkjet printing. As a result, the fabricated ink was dispersed for about 4 weeks, and after printing and heat treatment at $350^{\circ}C$ for 4 hours, the resistivity for the printed pattern was measured to be $1.15{\times}10^{-5}{\Omega}{\cdot}cm$.

• Conservation Science in Museum
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• v.12
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• pp.25-34
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• 2011

This study examined conservation process of white porcelain bottle with phoenix and peony design poly chrome, recovery of golden powder painted porcelain being damaged and colored, and recovery material and conservation methods by using a variety of experiments. Not only traditional method but also modern method can recover golden powder painted area being damaged and/or peel off, and suitable recovery was found out by using experiments. The golden powder paint of pattern edge was recovered not by traditional method but by modern method of golden powder paint with acrylic paint and binder.

• Korean Journal of Materials Research
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• v.9 no.6
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• pp.615-621
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• 1999

The new process in order to fabricate of Ni catalyst with high activity by the mechanochemical(MC) method which was combined the mechanical alloying(MA) and the chemical treatment process. The microstructure and characterization of mechanically alloyed Ni-5-wt% Al powder and Ni catalyst gained by alkali leaching were investigated byt he various analysis such as XRD, SEM-EDS, HRTEM and laser particle analyzer. The steady state powder with 1~2$\mu\textrm{m}$ mean particle size was obtained after 30hr milling with the PCA of 2 wt% stearic acid under the condition of grinding stainless steel ball to powder ratio of 60:1 and rotating speed fo 300rpm. According to result of HRTEM diffraction pattern, MA powder of the steady state was nanocrystalline $Al_3$$Ni_2$ intermetallic compound. Ni catalyst was obtained after KOH leaching of the steady state powder was about 20nm nanocrystalline which contained about 8 wt % Al.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.2
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• pp.136-140
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• 2002

The investment casting process is used frequently to manufacture precise and complex shape metal parts. The previous wax pattern manufacturing process takes long time and high costs because the process is performed by hands. In order to improve the wax manufacturing process, a new process is developed to manufacture the wax pattern by using a rapid prototyping system. A CastForm pattern is made by a Selective laser Sintering type RP with CastForm powder. The CastForm pattern is dipped in the melted wax liquid, and the melted wax penetrates into the pores of the CastForm pattern. Wax pattern is obtained after cooling the CastForm pattern slowly. A stainless steel part has been manufactured by the suggested process. By obtaining the suggested process the manufacturing time and costs are reduced largely and the accuracy is improved.

• The Korean Journal of Food And Nutrition
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• v.30 no.2
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• pp.282-289
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• 2017

This study was conducted to investigate the noodle-making characteristics of a noodle dough with konjac powder added. The water-binding capacity was significantly increased by increasing amounts of the konjac powder. When the weight and volume of the noodles were measured after cooking, there was no difference between the control and konjac powder groups. Turbidity was significantly reduced in a concentration-dependent manner. Chromaticity, in the case of raw noodle lightness (L), decreased significantly, while redness (a) and yellowness (b) significantly increased. Cooked noodles also showed the same pattern of results, however, as a whole, the results were lower when compared to wet noodles. The texture characteristics of hardness and chewiness significantly increased by increasing concentrations of the konjac powder. Cohesiveness was determined to not be significantly different by observing the surface of the noodle with a scanning electron microscope. In a sensory evaluation of the cooked noodle, no significant differences in gloss, taste, hardness, springiness or overall acceptability were observed between the control and konjac powder groups. This study indicates the that addition of 1.5% konjac powder to noodle dough may improve the functionality and preference of noodles.