• Resources Recycling
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• v.26 no.1
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• pp.16-21
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• 2017

This paper relates to the synthesis of a source powder for SiC crystal growth. ${\beta}-SiC$ powders are synthesized at high temperatures (>$1400^{\circ}C$) by a reaction between silicon powder and carbon powder. The reaction is carried out in a graphite crucible operating in a vacuum ambient (or Ar gas) over a period of time sufficient to cause the Si+C mixture to react and form poly-crystalline SiC powder. End-product characterizations are pursued with X-ray diffraction analysis, SEM/EDS, particle size analyzer and ICP-OES. The purity of the end-product was analyzed with the Korean Standard KS L 1612.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2017.11a
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• pp.241-242
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• 2017

본 논문에서는 폐유리를 재활용하는 발포유리에 대한 기술 및 활용방법에 대한 고찰을 통해 국내에서 적용 가능한 폐유리 재활용기술에 대하여 검토하였다. 폐유리를 재활용한 발포유리는 폐유리를 분쇄한 유리 미분에 규산나트륨, 탄산칼슘, 그라파이트 등의 발포제를 첨가하여 형틀에 넣고 가열을 하면, 유리분말은 소결(sinter)상태가 되는 약 $800^{\circ}C$ 정도가 되면 녹기 시작하고, 발포제는 분해되어 $O_2$와의 반응에서 발생하는 $CO_2$ 가스에 의한 기포가 발생하여 발포유리가 형성되는 제조 방식이다. 이러한 발포유리 방식으로 제작된 판재 및 배관 형태의 불연재료는 건설 및 LGN선박용으로 널리 활용되고 있고, 인공경량 골재의 형태는 건설용 채움재 및 빗물 저류용, 정화용으로 활용되고 있다. 이러한 활용 방식은 국내에서도 충분히 적용 가능한 방식이며, 국내에서의 적용을 통해 폐기물 및 환경부하 저감 효과를 높일 수 있다.

• Journal of the Korean Magnetics Society
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• v.27 no.3
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• pp.87-91
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• 2017

Carbon-encapsulated Ni and metal Ni nanoparticles were synthesized by levitational gas condensation (LGC). Methane ($CH_4$) gas was used to coat the surface of the Ni nanoparticles. The Ni particles had a core diameter of 10 nm, and were covered by 2~3 nm thin carbon layers with multi-shells structure.The low magnetization comparing with the Ni nanoparticles without carbon-shell results in the coexistence of nonmagnetic carbon and a large surface spin percentage with disordered magnetization orientation for the nanoparticles. Biginelli reactions in the presence of L-proline and Ni and carbon encapsulated Ni nanoparticles were carried out to change the ratio between stereoisomers. The obtained S-enantiomers for 3,4-dihydropyrimidine (DHPM) using catalysts of Ni, and Ni@C was an excess of about ${\Delta}{\sim}7.4%$ and ${\Delta}{\sim}19.6%$, respectively. The nanopowders were fully recovered using magnet to reuse as a catalyst. The Ni@C was shown at same yield to formation of 3,4-DHPM, though it was recycled for catalyst in the reaction.