• Title/Summary/Keyword: 나노과학

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Electron Field Emission Characteristics of Silicon Nanodots Formed by the LPCVD Technique (LPCVD로 형성된 실리콘 나노점의 전계방출 특성)

  • An, Seungman;Yim, Taekyung;Lee, Kyungsu;Kim, Jeongho;Kim, Eunkyeom;Park, Kyoungwan
    • Korean Journal of Metals and Materials
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    • v.49 no.4
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    • pp.342-347
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    • 2011
  • We fabricated the silicon nanodots using the low pressure chemical vapor deposition technique to investigate their electron field emission characteristics. Atomic force microscope measurements performed for the silicon nanodot samples having various process parameters, such as, deposition time and deposition pressure, revealed that the silicon nanodots with an average size of 20 nm, height of 5 nm, and density of $1.3\;{\times}\;10^{11}\;cm^{-2}$ were easily formed. Electron field emission measurements were performed with the silicon nanodot layer as the cathode electrode. The current-voltage curves revealed that the threshold electric field was as low as $8.3\;V/{\mu}m$ and the field enhancement factor reached as large as 698, which is compatible with the silicon cathode tips fabricated by other techniques. These electron field emission results point to the possibility of using a silicon-based light source for display devices.

Antioxidant activities of Pu-erh tea (보이차(Pu-erh tea)의 항산화 효과)

  • So, Eun Mee;Jung, Eun Joo;Shin, Chang Chul;Kim, Sung Hyun;Baek, Soon Ok;Kim, Young Man;Kim, Il Kwang
    • Analytical Science and Technology
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    • v.19 no.1
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    • pp.39-44
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    • 2006
  • Puh-erh tea was extracted with water and then fractionated sequentially with n-hexane, ethyl acetate, n-butanol to find antioxidative compounds. The fractions were examined on the antioxidant activity using two different methods, free radical scavenging activity measurement and reductive potential. Those antioxidant activities were compared to standard antioxidants such as butylated hydroxyanisole(BHA), butylated hydroxytoluene (BHT), and ${\alpha}$-tocopherol. EA fraction of Pu-erh tea was showed excellent antioxidative activities over BHA and BHT.

Silver ions and nanoparticles in the making (은이온 은나노 만들기: 은나노 세탁기를 둘러싼 나노의 정의와 위험 및 규제 관련 논쟁의 분석, 2006-2012)

  • Yoo, Sang Woon
    • Journal of Science and Technology Studies
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    • v.13 no.2
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    • pp.173-206
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    • 2013
  • Launched by Samsung in 2003, nano-silver washing machines were a representative application of nanotechnology in commercial products until the US Environment Protection Agency (EPA) decided to regulate companies that produce nano-silver products in 2006. A year later, however, the EPA reclassified the washing machines not as an application of nanotechnology but as an ion-generating machine. As shown by the EPA's equivocation on this issue, establishing a category for nano-silver material should be considered in the procedure of risk assessment and regulation. This paper analyzes the controversy over Samsung's nano-silver washing machines more in detail to study how the demarcation between silver ion and nano-silver can vary according to the risk perception of nanotechnology. In Korea and the US, the boundary between silver ion and nano-silver was malleable and mobilzed depending on the contexts. Based on an analysis of the recent history of nano-silver washing machines, this paper explores the influence of risk perception over the ontological perspectives on a certain material.

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Nanobio Colloidal Materials for Dermatological Applications (피부과학 나노바이오 콜로이드 개발 동향)

  • Kim, Ji Eun;Park, Daehwan;Lee, Jin Yong;Seo, Hyemin;Choi, Sang Koo;Kim, Jin Woong
    • Prospectives of Industrial Chemistry
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    • v.20 no.6
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    • pp.2-12
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    • 2017
  • 최근 피부산업은 미용적인 관점뿐만 아니라 피부질환치료에 대한 관심까지 폭넓게 성장하고 있어 피부의 건강을 개선하고 치료할 수 있는 새로운 신기술 개발이 다각적으로 이루어지고 있다. 특히 기술의 고도화와 체계화를 통한 피부과학기술의 진보가 화학, 화학공학, 재료공학을 기반으로 하는 전통학문분야와 조직공학, 바이오나노공학, 감성공학 등을 기반으로 하는 신학문분야가 융복합되어 이루어지고 있다. 따라서, 본 고에서는 피부산업에서 전략적인 응용이 가능한 피부 나노바이오 콜로이드의 연구개발에 대한 최근 현황을 소개하고자 한다.