• Title/Summary/Keyword: Graphite rod disk

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Tissue-Based Amperometric Biosensor for Determination of L-Ascorbic Acid in Organic Media (유기 용매 속에서 L-Ascorbic Acid의 정량을 위한 바이오센서)

  • Kwon, Hyo-Shik;Lee, Cheal-Gyu
    • Analytical Science and Technology
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    • v.7 no.2
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    • pp.149-153
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    • 1994
  • An amperometric sensor for L-ascorbic acid(AA) in methanol media has been made by immobilizing squash-tissues on a graphite rod disk. A detection limit of the electrode was $2{\times}10^{-6}M$ L-ascorbic acid. In comparison with an isolated enzyme based ascorbate oxidase(AO) electrode, the plant-tissue electrode offered high biocatalytic stability and activity and extremely low cost. The electrode has a useful lifetime of 1 week.

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Thermal Conductivity Enhancement of Polyimide Film Induced from Exfoliated Graphene Prepared by Electrostatic Discharge Method (정전기 방전에 의해 제조된 흑연박리 그래핀 첨가 폴리이미드 막의 열전도 향상)

  • Lim, Chaehun;Kim, Kyung Hoon;An, Donghae;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.32 no.2
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    • pp.143-148
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    • 2021
  • A thermally conductive 200 ㎛ thick polyimide-based film was made from a polyamic acid (PAA) precursor containing graphene prepared from graphite rod using an electrostatic discharge method in order to improve the thermal conductivity and expand the applicability of polyimide (PI) film. Properties of graphene produced by electrostatic discharge were measured by Raman spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy (XPS). As a result of Raman spectrum and XPS analyses of as-prepared graphene, the ID/IG ratio was 0.138 and C/O value was 24.91 which are excellent structural and surface chemical properties. Moreover, thermal conductivities of polyimide films increased exponentially according to graphene contents but when the graphene content exceeded 40%, the polyimide film could not maintain its shape. The thermal conductivity of carbonized PI film made from PAA containing 40 wt% of graphene was 51 W/mK which is greatly enhanced from the pristine carbonized PI film (1.9 W/mK). This result could be originated from superior properties of graphene prepared from the electrostatic discharge method.