• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.2
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• pp.104-108
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• 2013

In this paper, the $0.95(Na_{0.5}K_{0.5})_{0.04}[(Nb_{0.8}Ta_{0.20})_{0.994}Co_{0.015}]O_3$(abbreviated as NKNT) + $0.05KNbO_3$ lead-free piezoelectric ceramics were synthesized by the conventional mixed oxide method route with normal sintering. And also, the effects of calcination temperature on the microstructure, dielectric properties, and piezoelectric properties were investigated. A polymorphic phase transition(PPT) between orthorhombic and tetragonal phases was observed in specimens calcined at $810^{\circ}C{\sim}850^{\circ}C$. The ceramics calcined at $830^{\circ}C$ showed excellent piezoelectric properties: $d_{33}$= 179 pC/N, $k_p$= 0.384, $Q_m$= 79.73). These results indicate that the ceramic is a promising candidate material for lead-free piezoelectric ceramics.

• Fashion & Textile Research Journal
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• v.17 no.6
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• pp.996-1003
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• 2015

This study aims to examine the effects of the cutting amount at the waistline on the jacket appearance evaluation and movement functionality, and to suggest a proper waistline cutting amount when designing the men's casual jacket for those in their 30's. The researchers prepared 4 kinds of experimental jackets varying the waistline cutting amount: 0.0cm, 0.5cm, 1.0cm, and 1.5cm. The results of the study are as follows: Regarding the front view appearance, the jacket with the 0.5cm cutting amount achieved the highest score (6 out of 9). On the side view and the back view, there was no meaningful difference. However, the jacket with 0.5cm cutting amount achieved the highest score (4 out of 5). On the other hand, on the movement functionality, there was small statistical difference; the 1.5cm experimental jacket received the highest score in the most areas. This is resulted because if the cutting amount was increased, equally with the V-zone area which gives room for movements. This result showed the difference from the previous research of men in their 20’s,where 0.0cm achieved the highest test score for both appearance and movement functionality. Therefore, this study suggests using the 0.5cm and 1.5cm for the waistline cutting amount; for the jacket appearance 0.5cm is the best while the 1.5cm is better for the movement.

• Fashion & Textile Research Journal
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• v.18 no.2
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• pp.235-243
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• 2016

This study is a preliminary study to suggest a distinguished fitted sloper according to body types. To this end, this study classified body types of men in their 20s in an attempt to examine the characteristics of each type. A total of 842 adult men of age 20 to 29 were studied by using the direct measurement data taken in the 6th Size Korea. The subjects' body types were classified based on 48 measurements. We extracted a total of six factors that characterized the body types of adult men in their 20s: horizontal size, vertical length, shoulder development, trunk area length, hip area length and shoulder slope. Result of the cluster analysis, the body shapes of men in their 20s were classified into four types. We developed the overlapped silhouettes for each of the four body types and compared the front and side shapes to clearly identify the differences of each body types. The findings of this study indicated that Korean adult men in their 20s can be classified into the big inverted triangular type that represents healthy and muscular men, the small inverted triangular type that represents short and skinny men, the triangular type that represents men with abdominal obesity, and the rectangular type that represents men that are fat overall, with a fairly even distribution of each body type.

• Korean Journal of Materials Research
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• v.23 no.5
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• pp.271-275
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• 2013

Cobalt (Co) compounds have been used for centuries to impart rich blue color to glass, glazes and ceramics. Cobalt monoxide (CoO), an oxide of Co, is an inorganic compound that has long been used as a coloring agent in the ceramic industry. Unlike other coloring agents, CoO can be used to develop colors other than blue, and several factors such as its concentration in the glaze and firing condition have been suggested as possible mechanisms. For example, CoO produces a typical blue color called "cobalt blue" at very low concentrations such as 1 wt% in both oxidation and reduction firing conditions; a higher concentration of CoO (5 wt%) develops a darker blue color under the same firing conditions. Interestingly, CoO also develops a purple color at high concentrations above 10 wt%. In this study, we examined the applicability and mechanism of a novel purple glaze containing cobalt(II, III) oxide, one of the well characterized cobalt oxides. Experimental results show that an Augite crystal isoform (Augite-Fe/Co) in which Fe was replaced with Co is the main component contributing to the formation of the purple color. Based on these results, we developed a glaze using chemically synthesized Augite-Fe/Co crystal as a color pigment. Purple color glaze was successfully developed by the addition of 6~15 wt% of $Co_3O_4$ to magnesia lime.

• Journal of the Korea Fashion and Costume Design Association
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• v.17 no.4
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• pp.55-66
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• 2015

The objective of this study is to propose a method by which movement fitness can be evaluated using a three-dimensional virtual garment simulation program. To this end, five types of jean pants for men were evaluated on the program by setting the avatars to make particular movements to examine the level of pressure on each body part. To verify whether the clothing pressure measurement produces valid and reliable results, virtual garment simulation program was utilized. The results indicated that there were significant differences in the levels of pressure on body parts depending on the type of test garment and motion. In addition, the clothing pressure measurement results were in line with the appearance evaluation results suggested by a previous study. Based on this set of results, the nomological validity of the clothing pressure measurement program used in this study was verified. Moreover, we employed an appearance evaluation along with the clothing pressure measurement to verify the reliability of the program; there was a high correlation between clothing pressure measurements and appearance evaluation measurements, indicating that measuring clothing pressures may well compensate for the limitations of appearance evaluation. We expect the results of this study to make valuable contributions in facilitating the digitalization of the fashion industry. Furthermore, this study also is significant in that it has suggested 3D virtual fitting programs as a solution to the long-criticized problem related to the evaluation of movement fitness in existing virtual garment simulation programs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1509-1514
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• 2011

The core of IT products, electronic components, especially the MLCC, chip inductors, chip Varistors and so on. In order to test the electrical characteristics of the chip using the Reno-pin contact test method has been used. In current chips, mass production of semiconductor manufacturing processes, high-speed production test for the chip speed up, precision is required. But Vibration displacement is a very short, so in order to overcome these shortcomings, the displacement amplification to design the structure has been actively studied. In this paper, a building structure with a flexible hinge was designed amplification instrument, semiconductor chip industry in the performance test and inspection equipment to measure the electrical characteristics of high speed linear actuators Reno-Pin using system was developed.

• Korean Journal of Materials Research
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• v.19 no.1
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• pp.18-23
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• 2009

The influence of various surface morphologies on the mechanical strength of silicon substrates was investigated in this study. The yield for the solar cell industry is mainly related to the fracturing of silicon wafers during the manufacturing process. The flexural strengths of silicon substrates were influenced by the density of the pyramids as well as by the size and the rounded surface of the pyramids. To characterize and optimize the relevant texturing process in terms of mechanical stability and the fabrication yield, the mechanical properties of textured silicon substrates were investigated to optimize the size and morphology of random pyramids. Several types of silicon substrates were studied, including the planar type, a textured surface with large and small pyramids, and a textured surface with rounded pyramids. The surface morphology and a cross-section of the as-textured and fractured silicon substrates were investigated by scanning electron microscopy.

• Korean Journal of Materials Research
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• v.24 no.5
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• pp.255-258
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• 2014

Zirconium boride is an artificial or which is rarely found in the nature. $ZrB_2$ is popular in the hard material industry because it has a high melting point, excellent mechanical properties and chemical stability. There are two known methods to synthesize $ZrB_2$. The first involves direct reaction between Zr and B, and the second is by reduction of the metal halogen. However, these two methods are known to be unsuitable for mass production. SHS(Self-propagating High-temperature Synthesis) is an efficient and economic method for synthesizing hard materials because it uses exothermic reactions. In this study, $ZrB_2$ was successfully synthesized by subjecting $ZrO_2$, Mg and $B_2O_3$ to SHS. Because of the high combustion temperature and rapid combustion, in conjunction with the stoichiometric ratio of $ZrO_2$, Mg and $B_2O_3$; single phase $ZrB_2$ was not synthesized. In order to solve the temperature problem, Mg and NaCl additives were investigated as diluents. From the experiments it was found that both diluents effectively stabilized the reaction and combustion regime. The final product, made under optimum conditions, was single-phase $ZrB_2$ of $0.1-0.9{\mu}m$ particle size.

• Ceramist
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• v.21 no.4
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• pp.388-405
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• 2018

In this paper, we review about current development of electrode materials for Li-ion batteries and catalysts for fuel cells. We scrutinized various electrode materials for cathode and anode in Li-ion batteries, which include the materials currently being used in the industry and candidates with high energy density. While layered, spinel, olivine, and rock-salt type inorganic electrode materials were introduced as the cathode materials, the Li metal, graphite, Li-alloying metal, and oxide compound have been discussed for the application to the anode materials. In the development of fuel cell catalysts, the catalyst structures classified according to the catalyst composition and surface structure, such as Pt-based metal nanoparticles, non-Pt catalysts, and carbon-based materials, were discussed in detail. Moreover, various support materials used to maximize the active surface area of fuel cell catalysts were explained. New electrode materials and catalysts with both high electrochemical performance and stability can be developed based on the thorough understanding of earlier studied electrode materials and catalysts.

• Korean Journal of Materials Research
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• v.32 no.8
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• pp.354-360
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• 2022

In this study, an Co/Fe coated porcelain using a cobalt and ferrous sulfate was sintered at 1,250 ℃. The specimens were investigated by HR-XRD, FE-SEM (EDS), Dilatometer, and UV-vis spectrophotometer. The surface of the porcelain was uniformly fused with the pigment, and white ware and celadon body specimens were densely fused to a certain thickness from the surface. Other new compounds were produced by the chemical reaction of cobalt/ferrous sulfate with the porcelain body during the sintering process. These compounds were identified as cobalt ferrite spinel phases for white ware and white mixed ware, and an andradite phase for the celadon body, and the amorphous phase, respectively. As for the color of the specimens coated with cobalt and ferrous mixed pigments, it was found that the L^* value was greatly affected by the white ware, and the a^* and b^* values were significantly changed in the celadon body. The L^* values of the specimens fired with pure white ware, celadon body, and white mix ware were 72.1, 60.92, 82.34, respectively. The C7F3 pigment coated porcelain fired at 1,250 ℃ had L^* values of 39.91, 50.17, and 40.53 for the white ware, celadon body, and white mixed ware, respectively; with a^* values of -1.07, -2.04, and -0.19, and at b^* values of 0.46 and 6.01, it was found to be 4.03. As a new cobalt ferrite spinel phase was formed, it seemed to have had a great influence on the color change of the ceramic surface.