• Title/Summary/Keyword: 결함 성장

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A study about Strategy of Green Growth base on IT (IT롤 활용한 녹색성장 전략에 관한 연구)

  • Kim, Myung-Ho
    • Korean Business Review
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    • v.22 no.2
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    • pp.1-34
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    • 2009
  • We should have a new perspective on the words, green and growth, to have a full understanding of them and consider the environment itself as leading to the nation's growth. The green growth policy is to convert the paradigm of economic growth into one with a good circle of environment and growth. However, as each country has a different view of the green growth policy, we will see how the countries carry out the policy and how the companies and people accept it. To do this, we will employ an actual analysis and propose a green growth strategy for the nation. The following are from the actual analysis in the article: 1. The GG policy is not just limited on the environmental problems but related to the nation's well-being as well. 2. Energy policy should be defined as the core thing of the GG policy and energy effectiveness among others things should be carried out on a short term basis. 3. Developing a strategy using IT is necessary for the GG policy. 4. Very careful approach should be taken to build a master plan for the nation bearing effective outcome of the policy. 5. The GG policy should be regarded as a social reformative one motivating the nation's much interest in it.

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Solution Growth of SiC Single Crystal from Si-Cr-Co Solvent (Si-Cr-Co 용매로부터 SiC 단결정 용액성장)

  • Hyeon, Gwang-Ryong;Tsuchimoto, Naomich;Suzuk, Koki;Kim, Seong-Jong;Taishi, Toshinori
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2018.06a
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    • pp.113-113
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    • 2018
  • 환경 친화형 전기자동차, 하이브리드 자동차, 전철 등에서는 고내압 및 소형으로 전력손실을 감소시킬 수 있는 파워 디바이스가 필수이다. 최근, 실리콘 카바이드(SiC, silcon carbide)는 기존 실리콘(Si)보다 스위칭 손실의 저감 및 고온환경에서의 동작 특성이 우수하여, 차세대 저 손실 전력반도체 재료로서 기대를 받고 있다. 용액 성장 법에서 고품질 SiC 결정을 만들 수 있다. 그러나 늦은 성장 속도 때문에 SiC의 양산을 어렵게 하고 있다. 현재까지 성장 속도 향상을 위한 Si용매에 Cr을 첨가하여 탄소 용해도를 높이는 방법이 사용되고 안정된 성장을 위한 Si-Cr용매에 Al를 첨가하는 등 다양한 금속을 첨가하는 방법이 이용되고 있다. 선행 연구에서는 다양한 용매인 탄소 용해도를 실측하고 특히 큰 탄소 용해도를 보인 것은 Co이었다. 본 연구에서는 $Si_{0.6}Cr_{0.4}$원료와 Co를 첨가한 $Si_{0.56}Cr_{0.4}Co_{0.04}$의 용매에 의한 SiC용액 성장을 실시하고 결정 성장 속도 및 표면 상태의 변화를 검토했다. on-axis 4H-SiC(000-1)을 사용한 Top-seeded solution growth(TSSG)법과 원자 비율로 $Si_{0.6}Cr_{0.4}$$Si_{0.56}Cr_{0.4}Co_{0.04}$의 용매를 이용하여 SiC 용액 성장을 실시했다. Ar가스에서 저항 가열로 내를 치환 후에 $1800^{\circ}C$까지 가열하고 종자화 후에 120분간 유지하고 결정 성장을 실시했다. 냉각 후에 성장의 표면에 남은 용매를 $HF+HNO_3$에서 제거했다. 광학 현미경을 이용하여 결정면과 두께를 관찰 측정했다. Co를 첨가한 $Si_{0.56}Cr_{0.4}Co_{0.04}$의 경우는 $Si_{0.6}Cr_{0.4}$의 경우보다 결정 성장 속도가 향상됐다. 또한 $Si_{0.6}Cr_{0.4}$보다 step-flow의 성장을 나타낸 결정의 표면이 전반적으로 관찰됐으며 안정된 결정성장을 나타냈다. 본 연구에서 실시한 연구 방법과 결과는 고품질 및 고속의 SiC 용액성장을 위한 매우 유용한 자료로 활용 될 수 있을 것으로 판단한다.

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A Study on the Selection Area Growth of GaN on Non-Planar Substrate by MOCVD (MOCVD를 이용한 비평면구조 기판에서의 GaN 선택적 성장특성연구)

  • Lee, Jae-In;Geum, Dong-Hwa;Yu, Ji-Beom
    • Korean Journal of Materials Research
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    • v.9 no.3
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    • pp.257-262
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    • 1999
  • The selective area growth of GaN by metal organic chemical vapor deposition has been carried out on GaN/ sapphire substrate using $SiO_2$ mask. We investgated the effect of growth parameters such as flow rate of $NH_3$(500­~1300sccm) and the growth temperature(TEX>$950~1060^{\circ}C$) on the growth selectivity and characteristics of GaN using the Scanning Electron Microscopy(SEM). The selectivity of GaN improved as flow rate of NH, and growth temperature in­creased. But the grown GaN shapes on the substrate windows was independent of the flow rate of $NH_3$. On the pattern shapes such as circle, stripe, and radiational pattern(rotate the stripe pattern by $30^{\circ}, 45^{\circ}$), we observed the hexagonal pyramid, the lateral over growth on the mask layer, and the difference of the lateral growth rate depending on growth condition.

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Crystallinity and electrical properties of 6H-SiC wafers (6H-SiC wafer의 결정성 및 전기적 특성)

  • 김화목;임창성;오근호
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.7 no.3
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    • pp.393-399
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    • 1997
  • H-SiC single crystals were successfully grown by the sublimation method and the optimum growth conditions were established. The grown SiC crystals were about 33 mm in diameter and 11 mm in length. The micropipe density of the polished SiC wafers was 400/$\textrm{cm}^2$, and the planar defect density was 50/$\textrm{cm}^2$. Raman spectroscopy and DCXRD analysis were used to examine the crystallinity of Acheson seeds and the 6H-SiC wafers. As a result, the crystallinity of the 6H-SiC wafers was better than that of Acheson seeds. For examination of the electrical properties of the undopped 6H-SiC wafers Hall measurements were applied. According to the measurements the carrier concentration was estimated to be $3.91{\times}10^{15}/\textrm {cm}^3$ and doping type of the undopped. 6H-SiC wafers was n-type.

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Cu 도핑된 ZnO 나노구조의 성장 시간 변화에 따른 구조적 및 광학적 특성

  • Bae, Yong-Jin;No, Yeong-Su;Yang, Hui-Yeon;Kim, Tae-Hwan
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.405-405
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    • 2012
  • 에너지 갭의 크기가 큰 ZnO는 큰 여기자 결합과 높은 화학적 안정도를 가지고 있기 때문에 전자소자 및 광소자로 많이 응용되고 있다. ZnO는 광학적 및 전기적 성질의 여러 가지 장점 때문에 메모리, 나노발전기, 트랜지스터, 태양전지, 광탐지기 및 레이저와 같은 여러 분야에 많이 사용되고 있다. Zn와 쉘 구조가 비슷한 Cu 불순물은 우수한 luminescence activator이고 다양한 불순물 레벨을 만들기 때문에 전기적 및 광학적 특성을 변화하는데 좋은 도핑 물질이다. Cu가 도핑된 ZnO 나노구조를 전기화학적 증착법을 이용하여 형성하고, 형성시간의 변화에 따른 구조적 및 광학적 성질에 대한 관찰하였다. ITO 코팅된 유리 기판에 전기화학증착법을 이용하여 Cu 도핑된 ZnO를 성장하였다. Sputtering, pulsed laser vapor deposition, 화학기상증착, atomic layer epitaxy, 전자빔증발법 등으로 Cu 도핑된 ZnO 나노구조를 형성하지만 본 연구에서는 낮은 온도와 간단한 공정으로, 속도가 빠르고 가격이 낮아 경제적인 면에서 효율적인 전기 화학증착법으로 성장하였다. 반복실험을 통하여 Cu의 도핑 농도는 Zn과 Cu의 비율이 97:3이 되도록, ITO 양극과 Pt 음극의 전위차가 -0.75V로 실험조건을 고정하였고, 성장시간을 각각 5분, 10분, 20분으로 변화하였다. 주사전자현미경 사진에서 Cu 도핑된 ZnO는 성장 시간이 증가함에 따라 나노세선 형태에서 나노로드 형태로 변하였다. X-선 회절 측정결과에서 성장시간이 변화함에 따라 피크 위치의 변화를 관찰하였다. 광루미네센스 측정 결과는 Oxygen 공핍의 증가로 보이는 500~600 nm 대의 파장에서 나타난 피크의 위치가 에너지가 큰 쪽으로 증가하였다. 위 결과로부터 성장 시간에 따른 Cu 도핑된 ZnO의 구조적 및 광학적 특성변화를 관찰하였고, 이 연구 결과는 Cu 도핑된 ZnO 나노구조 기반 전자소자 및 광소자에 응용 가능성을 보여주고 있다.

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The Impact of ODA·FDI·Trade on the South America's Economic Growth; Comparative analysis of 4 countries (무역·ODA·FDI가 남미 경제발전에 미치는 영향 분석: 4개국 비교를 중심으로)

  • Choi, Chang Hwan
    • International Commerce and Information Review
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    • v.17 no.3
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    • pp.115-130
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    • 2015
  • This paper investigates how ODA FDI Trade affect economic growth in 4 South America countries over the last 50 years and ODA, FDI, Trade have a impact on the 4 South America countries economic growth using the Vector Error Correction Model. The results of empirical analysis based on data from 1960 to 2014 confirmed that FDI and trade than ODA has had a significant impact on Brazil and FDI, Trade had affected on Argentina economic growth. On the other hand, ODA had a more major impact on Venezuela, Peru economic growth than FDI and trade. Based on the results of these empirical analysis, when it comes to support for economic growth of underdeveloping countries, developed countries have to supply enough ODA for least developing countries to start economic growth, in case of economic take off stage, they should consider FDI, and international trade volume increase.

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Effects of Inhibitor Concentrations on the Growth of Recombinant E. chli (재조합된 대장균의 세포성장에 미치는 저해제의 영향)

  • 차월석;나재운이동병
    • KSBB Journal
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    • v.11 no.2
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    • pp.132-139
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    • 1996
  • The growth of recombinant E. coil and by-product production were investigated. D-cycloserine was added to increase the secretion of ${\alpha}$-amylase from recombinant E.coil. Even though cell growth was increased for optimal d-cycloserine concentration $0.1g/\ell$, extracellular ${\alpha}$-amylase activity remained almost the same as the case without d-cycloserine. It is important to achieve the high cell density for commercial production of methaboliles including ${\alpha}$-amylase. To achieve this goal, culture conditions should be selected carefully and optimized considering cell growth and by-products production. In cultivating retombinant E. coli, lactic acid and acetic acid turned out to be important by-product which affected cell yield and growth rate.

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Posttraumatic Growth in Cancer Survivors: The Application of Double ABCX Family Stress Model (암 생존자의 외상 후 성장 영향요인: Double ABCX 가족스트레스 모델의 적용)

  • Lim, Soo-Youb;Kim, Yeong-Hee
    • Journal of Convergence for Information Technology
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    • v.10 no.10
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    • pp.88-99
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    • 2020
  • This study aimed to explore the effects of perceived family stress, supportive resources, intentional rumination, and coping behaviors on posttraumatic growth of cancer survivors based on the Double ABCX Family Stress Model. Data were collected from 200 cancer survivors currently living with their spouses and analyzed by path analysis using AMOS program. The results of this study were as follows. First, perceived family stress of cancer survivors had direct effects on supportive resources, intentional rumination, and coping behaviors, and had indirect effects on posttraumatic growth mediated by supportive resources, intentional rumination, and coping behaviors. Second, supportive resources, intentional rumination, and coping behaviors had direct effects on posttraumatic growth. Third, supportive resources and intentional rumination had direct effects on coping behaviors and had an indirect effect on posttraumatic growth mediated by coping behaviors. The current study supported the applicability of the Double ABCX Family Stress Model to the posttraumatic growth process of cancer survivors.

A Growth-Stimulating Protein in Cow's Milk

  • Ki, Eun-Kyung;Park, Yong-Bok;Choi, Myung-Sook
    • Journal of the East Asian Society of Dietary Life
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    • v.4 no.3
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    • pp.59-65
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    • 1994
  • Growth-stimulating effects of cow's milk was examined using Vero cell cultre. Medium containing whole cow's milk stimulated cell growth about the same degree as that containing fetal bovine serum. The growth-stimulating factor in cow's milk was purified using hydrophobic (phenyl-sepharose) and gel filtration (Sephadex G-100) column chromatographies. It appeared that the factor is a highly hydrophobic protein, since the major growth-stimulating activity was found in the fractions eluted with 50% ethylene glycol from the phenyl-sepharose column during the purification. The purified factor showed a single band on the polyacrylamide gel electrophoresis in the presence of 1% (w/v) SDS. The factor has been found to have a relatively high molecular weight in the range of about Mr=100,000-150,000. In the presence of the purified factor (5%, w/v) in the culture medium, the incorporation of [3H]-thymidine into the cells was increased approximately 2,400-fold over that in the presence of 5% (w/v) fetal bovine serum. It seems that the growth-stimulating factor purified in this study is one of the major growth factors in the cow's milk.

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The roles of growth mindset and grit in relation to hope and self-directed learning (희망과 자기주도학습과의 관계에서 성장 마인드셋과 그릿의 역할)

  • Lee, Chang Seek;Jang, Ha Young
    • Journal of the Korea Convergence Society
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    • v.9 no.1
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    • pp.95-102
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    • 2018
  • Recently, according to the arrival of the knowledge-based society, the self-directed learning is necessary for the workers. Especially, the person with strong hopes showed strong self-directed learning, and the psychological characteristics and beliefs such as growth mindset and Grit would play a mediating role. The purpose of this study was to investigate the mediating effects of growth mindset and grit in relation to hope and self-directed learning. The subjects of this study were selected from than 32 workplace in cities of Seoul, Daejeon, Chungbuk, Chungnam, and consisted of 368 workers selected by purposive sampling. And data analysis was performed by frequency analysis, correlation analysis, and structural equation modeling. The major results were as follow. First, there were positively significant correlations among hope, growth mindset, grit, self-directed learning. Second, as a result of SEM, hope showed direct impact on self-directed learning. Third, hope had indirect effect through growth mindset and grit. Lastly, the limitations of this study and policy implications to increase self-directed learning of workers through hope, growth mindset and grit.