• Journal of the Mineralogical Society of Korea
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• v.31 no.2
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• pp.67-73
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• 2018

The objective of this study was to investigate the application of sulfate solvents for the economic and eco-friendly leaching of valuable metals from Au concentrate using an acid bake-water leaching system (AWS). AWS experiments were performed using an electric furnace with various baking temperatures ($100-500^{\circ}C$) and sulfate solvents ($H_2SO_4$, $K_2SO_4$, $(NH_4)_2SO_4$, $MgSO_4$, and $CaSO_4$). The efficiency of the valuable metal leaching increased as the baking temperature was increased to $400^{\circ}C$. Based on the AWS leaching time experiments, the maximum leaching rate occurred with the aqueous $(NH_4)_2SO_4$ solvent. This study demonstrates that aqueous $(NH_4)_2SO_4$ could be used as an effective solvent for valuable metal leaching using an AWS.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.5
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• pp.822-829
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• 2015

The purpose of this study was to evaluate the biological activities and quality properties of macaroons made with GABA rice powder and xylose. GABA rice powder was added to macaroons at weight percentages of 0, 2.5, and 3.5%. Hunter's color values ($L^*$, $a^*$, $b^*$), total sugar contents, total phenolics, ABTS and DPPH radical scavenging activities, textures, and sensory characteristics supplemented with different xylose and GABA rice powder contents were measured. As the ratio of GABA rice powder in macaroons increased, total phenol contents and ABTS and DPPH radical scavenging activities increased. In the texture profile analysis, fracturability and brittleness were lower as GABA rice powder content increased. In the sensory evaluation, significant differences (p<0.05) were observed in color, sweetness, texture, and overall acceptability depending on the addition of GABA rice powder to macaroons. Overall qualities of macaroons were different from GABA rice powder and xylose added ones. Therefore, xylose and GABA rice powder may be used to make healthy macaroons.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.3
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• pp.45-54
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• 2000

The effect of electropolishing far stamped leadframe on the removal of the edge burr and residual stress relief was examined. The present study showed that the electropolishing could be used for enhanced surface quality of stamped leadframes. The electropolishing was performed at the condition of 60% phosphoric acid electrolyte, 5 ampere of current and 3 cm electrode gap at $70^{\circ}C$ for 2 minutes for Alloy42 type leadframe, and $50^{\circ}C$ for 1.5 minutes for C-194 type leadframe. The FWHM values from X-ray diffraction showed that residual stress of electropolished leadframe recovered to the level of as-received raw materials and surface roughness measured by using AFM tuned out to be improved by 0.079 $\mu\textrm{m}$ and 0.014 $\mu\textrm{m}$ ($R_{rms}$) far alloy 42 and C-194 type leadframes, respectively. The plated thickness using XRF showed the improved uniformity in thickness variation by 0.4~0.5 $\mu\textrm{m}$ and grain growth, which is favorable for interface adhesion, was also observed from the bake test samples. We could certify dimensional stability of leadframe with inspection by means of 3D-topography and hardness measurements.