• Title/Summary/Keyword: Material Characterization

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Synthesis and Characterization of Soluble Polyimide as Membrane material

  • 전종영;현진호;탁태문
    • Proceedings of the Membrane Society of Korea Conference
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    • 1994.10a
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    • pp.56-57
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    • 1994
  • Polyimides are one of the most important classes of highperformance polymers. Due to their excellent electriccal, thermal, and high-temperature mechanical properties. The polyimide and its derivatives have found many applications. But their uses are limited by their poor solubilities. In fact, most polyimides were processed in the form of their precursors, polyamic acid, which were subsequently converted to the imide structure.

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Characterization Of YBCO HTSC-Thick film With addiction of $CeO_2$ ($CeO_2$첨가에 따른 YBCO고온초전도 후막의 특성)

  • 윤기웅;임성훈;홍세은;강형곤;한용희;한병성
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.239-242
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    • 2000
  • To fabricate YBa$_2$Cu$_3$O$_{x}$ thick film using diffusion process, $Y_2$BaCuO$_{5}$ and BaO+CuO as the material of substrate and the doping material were selected. CeO$_2$ in the doping material was mixed. As another doping material, YBa$_2$Cu$_3$O$_{x}$ was prepared for the comparison with BaO+CuO doping material. Each doping material was patterned on $Y_2$BaCuO$_{5}$ substrate by the screen printing method and then was annealed above peritectic reaction temperature of YBCO with a few step. It could be observed by X-ray diffraction patterns and SEM photographs that through the diffusion process of the $Y_2$BaCuO$_{5}$ and BaO+CuO, the YBa$_2$Cu$_3$O$_{x}$ phase was formed. With an amout of addition of CeO$_2$, the thickness of a formed YBa$_2$Cu$_3$O$_{x}$ decreased. x/ decreased.

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Preparation and Characterization of Spherical Carbon Composite for Use as Anode Material for Lithium Ion Batteries

  • Ahn, Byoung-Hoon;Lee, Sung-Man
    • Bulletin of the Korean Chemical Society
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    • v.31 no.5
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    • pp.1331-1335
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    • 2010
  • A novel spherical carbon composite material, in which nanosized disordered carbons are dispersed in a soft carbon matrix, has been prepared and investigated for use as a potential anode material for lithium ion batteries. Disordered carbons were synthesized by ball milling natural graphite in air. The composite was prepared by mixing the ball-milled graphite with petroleum pitch powder, pelletizing the mixture, and pyrolyzing the pellets at $1200^{\circ}C$ in an argon flow. The ballmilled graphite consists of distorted nanocrystallites and amorphous phases. In the composite particle, nanosized flakes are uniformly distributed in a soft carbon matrix, as revealed by X-ray diffractometer (XRD) and transmission electron microscopy (TEM) experiments. The composite is compatible with a pure propylene carbonate (PC) electrolyte and shows high rate capability and excellent cycling performance. The electrochemical properties are comparable to those of hard carbon.

Preparation and characterization of Melamine-Formaldehyde Resin Microcapsules Containing Fragrant Oil

  • Hwang, Jun-Seok;Kim, Jin-Nam;Wee, Young-Jung;Yun, Jong-Sun;Jang, Hong-Gi;Kim, Sun-Ho;Ryu, Hwa-Won
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.11 no.4
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    • pp.332-336
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    • 2006
  • In this study, melamine-formaldehyde microcapsules were prepared via in situ polymerization using peppermint oil as a core material, melamine-formaldehyde as the wall material, Tween 20 as the emulsifier, and poly (vinyl alcohol) as a protective colloid. The melamine-formaldehyde microcapsules prepared in this study were then evaluated with regard to their structures, thermal properties, particle size distributions, morphologies, and release behaviors.

Mycoflora and Enzymatic Characterization of Fungal Isolates in Commercial Meju, Starter for a Korean Traditional Fermented Soybean Product

  • Baek, Jin-Ho;So, Kum-Kang;Ko, Yo-Han;Kim, Jung-Mi;Kim, Dae-Hyuk
    • Mycobiology
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    • v.42 no.3
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    • pp.291-295
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    • 2014
  • Mycoflora was assessed in the commercial meju from four well-separated geographic origins. A total of 112 fungal isolates were identified by phenotypic characteristics and molecular taxonomy using sequencing the internal transcribed spacer of the rDNA and revealed 19 species from 13 genera. Enzymatic characteristics of protease and amylase, and mycotoxin production were analyzed.