• Title/Summary/Keyword: Inorganic Materials

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Synthesis of Polycarbosilane for SiC Precursor (II) (SiC의 Precursor Polycarbosilane의 합성 (II))

  • Han, Chul;Lee, Hyung-Bock;Chung, Yun-Joong
    • Journal of the Korean Ceramic Society
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    • v.25 no.5
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    • pp.518-522
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    • 1988
  • Polycarbosilane was synthesized from polydimethylsilane at 42$0^{\circ}C$, pyrolysis temperature with various times And IR, NMR, UV, and GPC were detected. Average molecular weight Mn was increased proportionally with the reaction time. Average molecular weight of polycarbosilane was about 700(n=20), which has chain structure and the product yield was 72%.

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Development of Carbon Nanotubes and Polymer Composites Therefrom

  • Jain, P.K.;Mahajan, Y.R.;Sundararajan, G.;Okotrub, A.V.;Yudanov, N.F.;Romanenko, A.I.
    • Carbon letters
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    • v.3 no.3
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    • pp.142-145
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    • 2002
  • Multiwall carbon nanotubes (MWNT) were produced using the arc-discharge graphite evaporation technique. Composite films were developed using MWNT dispersed in polystirol polymer. In the present work, various properties of the polymeric thin film containing carbon nanotubes were investigated by optical absorption, electrical resistivity and the same have been discussed.

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Characterization of $BaO-B_2O_3-SiO_2$ glass for the application to PDP;Effect of BaO/$B_2O_3$ ratio

  • Lim, Eun-Sub;Kim, Byung-Sook;Lee, Joon-Hyung;Kim, Jeong-Joo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.1099-1102
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    • 2004
  • For the development of Pb-free low temperature sintering glass frits, $BaO-B_2O_3-SiO_2$ system was examined. The content of BaO and $B_2O_3$ was changed when the content of $SiO_2$ was fixed to 10 mol%. When the content of BaO was more than 60 mol% devitrification was observed. In the sintering temperature range between 520${\sim}$620 $^{\circ}C$, the optimum sintering temperature decreased as the content of BaO increased. When BaO ${\geq}$45 mol%, the glasses were crystallized after sintering. Candidate compositions are suggested in $BaO-B_2O_3-SiO_2$ system, which can replace the PbO containing glass system.

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Thermal and electrical properties of $Bi_2O_3-B_2O_3-ZnO$ glasses for the application to plasma display panel

  • Kim, Byung-Sook;Lim, Eun-Sub;Lee, Joon-Hyung;Kim, Jeong-Joo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.1095-1098
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    • 2004
  • In this study, $Bi_2O_3-B_2O_3-ZnO$ glass system, which was expected to have similar properties with PbO containing glass system, was selected as a PbO replaceable potential composition because the atomic weight and ionic radius of Bi is similar to those of Pb. Glasses with different modifier/former ratio were prepared by melting the raw ingredient mixtures in $Bi_2O_3-B_2O_3-ZnO$ system, and the thermal and electrical properties of the sintered samples were examined. The glass transition temperatures and the dielectric constant of the glass pellets were between 350 $^{\circ}C{\sim}$500 $^{\circ}C$ and 15-35, respectively.

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Growth of Sapphire Crystals by Verneuil Method (Verneuil법에 의한 Sapphire단결정 성장)

  • Joo, K.;Bae, S.Y.;Choi, J.K.;Orr, K.K.;Son, S.K.;Beun, Y.J.;Chun, H.T.
    • Journal of the Korean Ceramic Society
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    • v.25 no.5
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    • pp.495-501
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    • 1988
  • Verneuil method uses oxyhydrogen flame for its heat source. This method was used to grow corundum monocrystals. Parametersof this method are feeding rate, gas pressure, lowering rate and growth axis. These parameters were examined. Crystals's qualities and shapes are affected by these parameters. Crystals having good qualities and shape were grown under the conditions that feeding rate, 0.2∼0.5g/min, lowering rate, 10∼20mm/hr ; gas pressure, 3∼4psi ; growth axis was shifted 60 degrees from c axis.

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