• Clean Technology
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• v.16 no.3
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• pp.220-228
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• 2010

Four Keggin-type heteropolyacids, $H_nXM_{12}O_{40}$(X = P and Si, M = W and Mo) that were substituted with heteroatom and polyatom were applied to the dehydration reaction of fructose to 5-hydroxymethylfurfural (HMF). The results showed that the acid became stronger when the heteroatom and polyatom were substituted with P and W than the cases of Si and Mo, respectively. However, the amount of acidic sites increased with the decrease in the acid strength, resulting in the change of the catalytic activity of heteropolyacids in the dehydration reaction. The experimental results revealed that four different heteropolyacids produced similar amounts of HMF via the dehydration reaction of fructose due to the counterbalancing effect between the amount of active sites, which is related to the catalytic activity of heteropolyacids, and the softness of polyanion. In addition, it was observed that the prepared heteropolyacids showed good structural stability after heat treatment at $200^{\circ}C$.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.1
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• pp.5-14
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• 2023

In this study, LiDAR-reflective black hollow-structured silica/titania(B-HST) materials are successfully synthesized by employing the NaBH₄ reduction and etching method on silica/titania core/shell(STCS) materials, which also effectively enhance near-infrared(NIR) reflectance. Moreover, core-etched supernatant solutions are collected and recycled for the synthesis of extracted silica(e-SiO₂) process, which successfully applies as filler materials for semiconductor epoxy molding compound(EMC). In detail, B-HST materials, fabricated by the sequential experimental steps of sol-gel, reduction, and sonication-mediated etching method, manifest blackness(L^*) of 13.2 similar to black paint and excellent NIR reflectance(31.1%). Consequently, B-HST materials are successfully prepared as LiDAR-reflective black materials. Additionally, core-etched supernatant solution with silanol precursors are employed for synthesis of homogeneous silica filler materials via sol-gel method. As-synthesized silica fillers are incorporated with epoxy resin and carbon black for the preparation of semiconductor EMC. Experimentally synthesized EMC exhibits comparable mechanical-chemical properties to commercial EMC. Conclusively, this study successfully proposes designing procedure and practical experimental method for simultaneously synthesizing the NIR-reflective black materials for self-driving vehicles and EMC materials for semiconductors, which are materials suitable for the industrial 4.0 era, and presented their applicability in future industries.

• Journal of the Korean Electrochemical Society
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• v.27 no.3
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• pp.88-96
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• 2024

Lithium metal has garnered attention as a promising anode active material thanks to its high specific capacity, energy density, and the lowest reduction potential. However, the formation of dendrites, dendritic crystals that arise during the charge and discharge process, has posed safety and lifetime stability challenges. To resolve this, our study has introduced a novel separator design. This separator features a composite coating of vapor-grown carbon fiber, a conductive material in nanofibers, and silver. We have meticulously studied the impact of this innovative separator on the electrochemical properties of the lithium metal anode, unveiling promising results. To confirm the synergistic effect of VGCF and Ag, a separator with no surface treatment and a separator with only VGCF coated on one side were prepared and compared with the Ag-VGCF-separator. In the case of the bare separator, the Li metal surface is covered with dendrites during the initial charge and discharge process. In contrast, both the VGCF-separator and the Ag-VGCF-separator show Li precipitation inside the conductive coating layer coated on the separator surface. Additionally, the Ag-VGCF-separator showed a more uniform precipitate shape than the VGCF-separator. As a result, the Ag-VGCF-separators show improved electrochemical properties compared to the bare separators and the VGCF-separators.

• Journal of the Korea Organic Resources Recycling Association
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• v.32 no.3
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• pp.57-66
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• 2024

In this study, silicon sludge from a semiconductor packaging process is recycled to fabricate silica coated silicon-sludge and applied as a filler for an epoxy molding compound(EMC). Silicon-sludge powder(S-sludge) is treated with acid to remove metallic impurities and then coated using the sol-gel method to synthesize silica coated silicon-sludge powder(SS-sludge). The as-synthesized SS-sludge is subsequently mixed with epoxy resin, a curing agent, and carbon black to create an EMC(SS-sludge EMC). The heat dissipation properties of the EMC were examined using an IR camera. IR camera analysis confirmed that the SS-sludge EMC exhibited the highest surface temperature of 58.5℃ compared to SiO₂-based EMC. This enhancement in heat dissipation using SS-sludge EMC is attributed to the excellent thermal conductivity(150W/mK) of the silicon substrate and the presence of the silica layer on the SS-sludge surface which effectively enhances the thermal property of the EMC. Therefore, this study successfully demonstrates the recycling of silicon sludge from a semiconductor packaging process by synthesizing silica coated silicon-sludge and suggests a novel application of this material in semiconductor packaging.

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.19-22
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• 2007

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.85-87
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• 2014

• Proceedings of the KOSOMBE Conference
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• v.1994 no.05
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• pp.109-110
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• 1994

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.141-141
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• 1995

• Proceedings of the KOSOMBE Conference
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• v.1990 no.11
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• pp.1-4
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• 1990

• Proceedings of the KOSOMBE Conference
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• v.1985 no.06
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• pp.54-57
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• 1985