• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.129-129
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• 2016

Graphene, as a single layer of $sp^2$-bonded carbon atoms packed into a 2D honeycomb crystal lattice, has attracted much attention due to its outstanding properties. In order to synthesize high quality graphene, transition metals, such as nickel and copper, have been widely employed as catalysts, which needs transfer to desired substrates for various applications. However, the transfer steps are not only complicated but also inevitably induce defects, impurities, wrinkles, and cracks of graphene. Furthermore, the direct synthesis of graphene on dielectric surfaces has still been a premature field for practical applications. Therefore, cost effective and concise methods for transfer-free graphene are essentially required for commercialization. Here, we report a facile transfer-free graphene synthesis method through nickel and carbon co-deposited layer. In order to fabricate 100 nm thick NiC layer on the top of $SiO_2/Si$ substrates, DC reactive magnetron sputtering was performed at a gas pressure of 2 mTorr with various Ar : $CH_4$ gas flow ratio and the 200 W DC input power was applied to a Ni target at room temperature. Then, the sample was annealed under 200 sccm Ar flow and pressure of 1 Torr at $1000^{\circ}C$ for 4 min employing a rapid thermal annealing (RTA) equipment. During the RTA process, the carbon atoms diffused through the NiC layer and deposited on both sides of the NiC layer to form graphene upon cooling. The remained NiC layer was removed by using a 0.5 M $FeCl_3$ aqueous solution, and graphene was then directly obtained on $SiO_2/Si$ without any transfer process. In order to confirm the quality of resulted graphene layer, Raman spectroscopy was implemented. Raman mapping revealed that the resulted graphene was at high quality with low degree of $sp^3$-type structural defects. Additionally, sheet resistance and transmittance of the produced graphene were analyzed by a four-point probe method and UV-vis spectroscopy, respectively. This facile non-transfer process would consequently facilitate the future graphene research and industrial applications.

• 방사성폐기물학회지
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• 제6권4호
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• pp.245-255
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• 2008

중 저준위방사성폐기물 처분부지에 대한 건설 및 운영 인허가 취득을 위한 종합적인 부지특성조사가 사업자인 한국수력원자력(주)의 책임 하에 이루어졌으며, 수리지질조사는 부지의 수리지질학적 특성 해석과 방사선적 안전성 평가를 위한 기초자료 생산을 목적으로 수행되었다. 처분부지의 수리지질특성은 주로 지표에서 이루어진 지질조사, 시추조사, 각종 수리시험 및 지구물리탐사 자료를 종합적으로 분석하여 수리지질체계의 특성을 평가하고, 이를 토대로 수리토양영역, 3 개의 수리암반영역 및 5 개의 투수성구조영역으로 구성되는 수리-구조모델을 제시하였다. 본 논문에서 제시된 수리-구조모델과 수리인자는 지하수유동모델 해석 업무에 직접 이용되었다. 본 논문의 결과는 지표조사단계에서 얻어진 자료에 근거한 것이므로 수리지질특성과 관련된 제반 조사방법에 가정과 불확실성이 내재되어 있다. 따라서 현재 진행 중인 지하시설 건설과정에 취득되는 직접적인 수리지질특성 관련 자료를 종합적으로 재 해석함으로써 부지특성조사 단계에서의 가정과 불확실성을 저감시킬 수 있고, 최종적인 수리-구조모델의 신뢰성 향상을 기대할 수 있다.