• 제목/요약/키워드: nano technology

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Spin Hall effect in Au films

  • Kim, Seong-Hoon;Eom, Jong-Hwa;Chang, Joon-Yeon;Han, Suk-Hee
    • 한국자기학회:학술대회 개요집
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    • 한국자기학회 2006년도 동계학술연구발표회 및 자성 스핀트로닉스 국제학술대회
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    • pp.74-75
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    • 2006
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Effects of Nano-silica/Nano-alumina on Mechanical and Physical Properties of Polyurethane Composites and Coatings

  • Swain, Sarojini;Sharma, Ram Avatar;Bhattacharya, Subhendu;Chaudhary, Lokesh
    • Transactions on Electrical and Electronic Materials
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    • 제14권1호
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    • pp.1-8
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    • 2013
  • The present approach shows the use of nano-silica/nano-alumina in polyurethane (PU) matrix, which lead to significant improvements in the mechanical and thermal properties of the nano-composite. It is observed that with incorporation of 1% of nano-alumina into the PU matrix, there is an improvement in the tensile strength of around 50%, and for nano-silica the improvement is around 41%, at the same concentration. The morphological data shows that above 3% of the nano particles there are agglomerations in the nanocomposite. Again with the absorption of moisture, there is a decrease in the thermal and mechanical properties of the PU resin, but in this research work it is observed that with the incorporation of the nano particles, in the presence of absorbed moisture there is an improvement in mechanical and thermal properties of the composite, over that of the PU matrix.

Surface Discharge Characteristics of New Flat Fluorescent Lamp Enhanced by MgO Nano-Crystals

  • Lee, Yang-Kyu;Heo, Seung-Taek;Lee, You-Kook;Lee, Dong-Gu
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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    • pp.687-690
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    • 2009
  • It has been recently reported that nano-sized MgO single crystal powders emit ultraviolet by stimulation of electrons under vacuum condition. Therefore, in this study, nano-crystalline MgO powders were applied to a xenon plasma flat fluorescent lamp for LCD backlight to improve emission efficiency of the lamp by help of extra ultraviolet from nano-MgO. For comparison with nano-crystalline MgO powders, MgO nano-thin film was applied directly on phosphors inside a lamp panel through e-beam evaporation The luminance and efficiency of FFL with an addition of MgO nano-crystal powders on phosphors were improved by around 20%. Application of MgO thin film to phosphors worsened the emission characteristics of FFLs, even rather than FFL without MgO. The reason came from insufficient stimulation of phosphors by UV, crystallinity of MgO, and low secondary electron coefficient.

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확산판의 투과율이 고출력 양자점 조명의 광특성에 미치는 영향에 대한 연구 (Study of the Effect of the Transmittance of a Diffuser Plate on the Optical Characteristics of High-power Quantum-dot Illumination)

  • 김혜린;유동근;유재환;장준원;최무규;홍승찬;고재현;조성윤;김용득;박태희;고영욱
    • 한국광학회지
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    • 제32권5호
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    • pp.220-229
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    • 2021
  • 눈부심 방지를 위한 확산판의 투과율과 연색지수 향상을 위한 양자점 필름의 농도가 고출력 직하형 백색 LED 조명의 광특성에 미치는 영향을 조사했다. 확산판의 투과율이 감소할 경우 조명의 휘도는 줄어들었고 색좌표, 상관색온도는 별다른 변화를 보이지 않았으며 연색지수는 약간 상승했다. 시야각에 따른 광특성의 편차는 거의 없었고 휘도 분포는 람버시안 분포에 가까웠다. 양자점 필름의 농도가 증가할 경우 스펙트럼 상 적색 성분이 늘어나면서 이 성분의 비중을 표현하는 색좌표 x가 증가했고 상관색온도는 약 6000 K에서 4000 K 부근으로 현저히 감소했다. 아울러 조명의 구조를 최적화하면 연색지수가 95까지 증가함을 확인했다. 이런 결과는 적절한 투과율의 확산판과 양자점 필름의 조합을 통해 눈부심이 없고 시야각에 따른 색편차가 거의 없으며 특히 색좌표의 가변이 가능한 고연색성의 조명 구현이 가능함을 보여준다.

Preparation and Characterizations of C60/Polystyrene Composite Particle Containing Pristine C60 Clusters

  • Kim, Jung-Woon;Kim, Kun-Ji;Park, Soo-Yeon;Jeong, Kwang-Un;Lee, Myong-Hoon
    • Bulletin of the Korean Chemical Society
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    • 제33권9호
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    • pp.2966-2970
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    • 2012
  • Fullerene/polystyrene ($C_{60}$/PS) nano particle was prepared by using emulsion polymerization. Styrene and fullerene were emulsified in aqueous media in the presence of poly(N-vinyl pyridine) as an emulsion stabilizer, and polymerization was initiated by water soluble radical initiator, potassium persulfate. The obtained nano particles have an average diameter in the range of 400-500 nm. The fullerene contents in the nano particle can be controlled up to 15 wt % by varying the feed ratio, which was confirmed by themogravimetric analysis (TGA) and elemental analysis (EA). The structure and morphologies of the $C_{60}$/PS nano particles were examined by various analytical techniques such as dynamic light scattering (DLS), scanning electron microscope (SEM), transmission electron microscope (TEM), electron diffraction (ED) pattern, X-ray powder diffraction (XRD), and UV spectroscopy. Unlike conventional $C_{60}$/PS particles initiated by organic free radical initiators, in which the fullerene is copolymerized forming a covalent bond with styrene monomer, the prepared $C_{60}$/PS nano particles contain pristine fullerene as secondary particles homogeneously distributed in the polystyrene matrix.