• 제목/요약/키워드: Sejong-si

검색결과 189건 처리시간 0.041초

세종시 금강 우안(右岸)지역의 지형특성과 홀로세 후기 고환경복원 (The Geomorphic Characteristics and Late-Holocene Paleoenvironmental Reconstruction in Sejong-Si Based on the Pollen Analysis of the Right Bank of Geumgang)

  • 문영롱;윤순옥;황상일
    • 한국지형학회지
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    • 제24권4호
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    • pp.1-12
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    • 2017

  • This study tried to reconstruct paleovegetation environments during the late Holocene with pollen analysis from archeological trenches at the right bank of Geumgang in Sejong-si. The lower hills was dominantly covered with pine trees, while alder trees and hygrophytes extended on the floodplain since 2,000yr BP. The pollen composition of Alnus dominance in the floodplain during the times is different from the general charateristics of Korean peninsula. Such a phenomenon is thought to be influenced by the fluvial process on the floodplain in the middle reaches of Geumgang around Sejong-si. Mihocheon and some tributaries join to Geumgang around Sejong-si, and the channel of Geumgang becomes narrow around the boundary between Sejong-si and Gongju-si. This narrow channel could attribute to the formation of extensive floodplain around Sejong-si. Moreover, human impacts such as agriculture appear continuously since 1,800yr BP.

  • https://doi.org/10.16968/JKGA.24.4.1 인용

신경망을 이용한 전하밀도의 예측과 해석 (Prediction and Analysis of Charge Density Using Neural Network)

  • 권상희;황보광;이규상;우형수;김병환
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2007년도 추계학술대회 논문집
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    • pp.111-112
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    • 2007

  • Silicon nitride (SiN) 박막을 플라즈마 응용화학기상법을 이용하여 증착하였다. SiN박막의 전하밀도는 일반화된 회귀 신경망과 유전자 알고리즘을 이용하여 모델링하였다. PECVD 공정은 Box Wilson 실험계획표를 이용하여 수행하였다. $SiH_4$ 유량변화에 따른 온도의 영향은 미미하였다. 그러나, 저 전력에서의 온도증가 (또는 저온에서의 전력의 증가)에 따라 전하밀도는 급격히 상승하였으며, 이는 [N-H]의 증가에 기인하는 것으로 해석되었다. $SiH_4$ 유량의 증가 (또는 고온에서의 전력의 증가)에 따라 전하밀도는 감소하고 있으며, 이는 [Si-H]의 증가에 기인하는 것으로 이해된다.

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결정질 실리콘 태양전지의 반사방지막 비교 분석 (Comparison & Analysis of Anti-Reflection Coatings for Crystalline Si Solar cells)

  • 조경연;이지훈;이수홍;이규상
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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    • pp.221-222
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    • 2008

  • In Crystalline Si solar cells, Anti-Reflection Coating is contribute to improvement in energy conversion efficiency due to decrease of optical loss and recombination owing to surface passivation. Porous Si is formed electrochemical etching that uses chemical solution and anodization etching. So It gives that advantage in rapid process time and without high cost equipment. In this paper, We compare Porous Si with $SiO_2$/SiNx ARC and analyze that by anti-reflection coating.

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신경망을 이용한 PECVD 공정변수에 따른 SiNx 박막의 특성 예측 (Prediction of SiNx Thin Film Properties dependent on PECVD Process Parameter Using Neural Network Modeling)

  • 김은영;윤성연;김병환;김정
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 하계학술대회 논문집
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    • pp.206-206
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    • 2010

  • 본 연구에서는 신경망을 이용하여 SiN 박막의 특성을 예측하는 모델을 개발하였다. 신경망으로는 일반화된 회귀 신경망 (generalized regression neural network-GRNN)을 이용하였고, GRNN 모델의 예측수행은 유전자 알고리즘 (genetic algorithm-GA)을 이용하여 최적화 하였다. 개발된 모델을 이용하여 증착률과 굴절률 및 균일도를 공정변수의 함수로 예측하였다.

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Pulsed-PECVD를 이용한 SiN 박막의 저 소스전력 $SiH_4-N_2$ 플라즈마에서의 상온 증착 (Room temperature deposition of SiN at low radio frequency source power, $SiH_4-N_2$ plasma using pulsed-PECVD)

  • 이수진;김병환;우형수
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 하계학술대회 논문집
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    • pp.309-309
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    • 2010

  • Silicon Nitride(SiN) 박막을 펄스드 플라즈마 응용화학기상법을 이용하여 저 소스전력의 $SiH_4-N_2$ 플라즈마에서 증착하였다. Duty ratio의 변화에 따른 이온에너지와 굴절률의 변화를 고찰하였다. 저이온에너지는 증착률과 강한 상관성을 보였다. 이온에너지 변수의 증착률에의 영향은 신경망 모델을 이용하여 고찰하였다.

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Density Functional Theory Study of Silicon Chlorides for Atomic Layer Deposition of Silicon Nitride Thin Films

  • Yusup, Luchana L.;Woo, Sung-Joo;Park, Jae-Min;Lee, Won-Jun
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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    • pp.211.1-211.1
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    • 2014

  • Recently, the scaling of conventional planar NAND flash devices is facing its limits by decreasing numbers of electron stored in the floating gate and increasing difficulties in patterning. Three-dimensional vertical NAND devices have been proposed to overcome these issues. Atomic layer deposition (ALD) is the most promising method to deposit charge trap layer of vertical NAND devices, SiN, with excellent quality due to not only its self-limiting growth characteristics but also low process temperature. ALD of silicon nitride were studied using NH3 and silicon chloride precursors, such as SiCl4[1], SiH2Cl2[2], Si2Cl6[3], and Si3Cl8. However, the reaction mechanism of ALD silicon nitride process was rarely reported. In the present study, we used density functional theory (DFT) method to calculate the reaction of silicon chloride precursors with a silicon nitride surface. DFT is a quantum mechanical modeling method to investigate the electronic structure of many-body systems, in particular atoms, molecules, and the condensed phases. The bond dissociation energy of each precursor was calculated and compared with each other. The different reactivities of silicon chlorides precursors were discussed using the calculated results.

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기계적 합금화에 의해 제조된 Ti5Si3 분말의 전기방전소결 특성 연구 (Characteristic Studies on Electro-Discharge-Sintering of Ti5Si3 Powder Synthesized by Mechanical Alloying)

  • 천연욱;조유정;강태주;김정열;박준식;변창섭;이상호;이원희
    • 대한금속재료학회지
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    • 제47권10호
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    • pp.660-666
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    • 2009

  • The consolidation of mechanical alloyed $Ti_5Si_3$ powder by electro-discharge-sintering has been investigated. A single pulse of 2.5 to 8.0 kJ/0.34 g was applied to each powder mixture using 300 and $450{\mu}F$ capacitors. A bulk-like solid with $Ti_5Si_3$ phase has been successfully fabricated by the discharge with an input energy of more than 2.5 kJ in less than $160{\mu}sec$. Micro-Vickers hardness was found to be higher than 1350, which is significantly higher than that of a conventional high temperature sintered sample. The formation of $Ti_5Si_3$ and consolidation occurred through a fast solid state diffusion reaction.

  • KSCI