• 제목/요약/키워드: amorphous materials

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탄소-실리카막을 이용한 기체분리 (Carbon-Silica Membrane for Gas Separation)

  • Lee, Young-Moo;Park, Ho-Bum
    • 한국막학회:학술대회논문집
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    • 한국막학회 2004년도 첨단 분리막 연구동향
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    • pp.77-102
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    • 2004
  • Carbon materials obtained from organic polymers are usually amorphous structure. The structure of carbon materials is not nearly as well defined as that of zeolite. Carbon are amorphous materials with comparatively wide pore size distribution as compared to the crystalline zeolites with monodisperse ultramicropore and micropore dimensions. (omitted)

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Structure and Optical Properties of the Ca/Ag Double Layer for Transparent Cathode in TEOLED

  • Kim, Boo-Kyung;Moon, D.G.;Ahn, B.T.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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    • pp.1071-1074
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    • 2006
  • Ca/Ag double layer which is fabricated by thermal evaporation exists as the double layer of (Ca+O)/(Ag+Ca). In Ca layer, are crystalline Ca(OH)2 and amorphous Ca and in Ag layer, are crystalline Ag and amorphous Ca. And for the certain thickness of Ag, in the Ca/Ag double layer, the thicker Ca is, the higher transmittance is.

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Microwave-Enhanced Low-Temperature Crystallization of Amorphous Silicon Films for TFTs

  • Ahn, Jin-Hyung;Eom, Ji-Hye;Ahn, Byung-Tae
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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    • pp.177-180
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    • 2002
  • Microwave has been utilized for low-temperature crystallization of amorphous Si films. Microwave annealing lowered the crystallization temperature and shortened the annealing time. The combination of Ni and microwave applications on a-Si films further enhanced the crystallization. The enhancement was due to both reduced nucleation activation energy and growth activation energy.

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Joule-heating induced crystallization (JIC) of amorphous silicon films

  • Hong, Won-Eui;Lee, Joo-Yeol;Kim, Bo-Kyung;Ro, Jae-Sang
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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    • pp.459-462
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    • 2007
  • An electric field was applied to a conductive layer to induce Joule heating in order to carry out the crystallization of amorphous silicon. Polycrystalline silicon was produced through a solid state transformation within the range of a millisecond. Uniformly distributed grains were obtained due to enormously high heating rate.

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Thermal stability, magnetic and magnetocaloric properties of Gd55Co35M10 (M = Si, Zr and Nb) melt-spun ribbons

  • Jiao, D.L.;Zhong, X.C.;Zhang, H.;Qiu, W.Q.;Liu, Z.W.;Ramanujan, R.V.
    • Current Applied Physics
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    • 제18권12호
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    • pp.1523-1527
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    • 2018
  • The thermal stability, magnetic and magnetocaloric properties of $Gd_{55}Co_{35}M_{10}$ (M = Si, Zr and Nb) melts-pun ribbons were studied. The relatively high reduced glass transition temperature ($T_{x1}/T_m$ > 0.60) and low melting point ($T_m$) resulted in excellent glass forming ability (GFA). The Curie temperatures ($T_C$) of melt-spun amorphous ribbons $Gd_{55}Co_{35}M_{10}$ for M = Si, Zr and Nb were 166, 148 and 173 K, respectively. For a magnetic field change of 2 T, the values of maximum magnetic entropy change $(-{\Delta}S_M)^{max}$ for $Gd_{55}Co_{35}Si_{10}$, $Gd_{55}Co_{35}Zr_{10}$ and $Gd_{55}Co_{35}Nb_{10}$ were found to be 2.86, 4.28 and $4.05J\;kg^{-1}K^{-1}$, while the refrigeration capacity (RC) values were 154, 274 and $174J\;kg^{-1}$, respectively. The $RC_{FWHM}$ values of amorphous alloys $Gd_{55}Co_{35}M_{10}$ (M = Si, Zr and Nb) are comparable to or larger than that of $LaFe_{11.6}Si_{1.4}$ crystalline alloy. Large values of $(-{\Delta}S_M)^{max}$ and RC along with good thermal stability make $Gd_{55}Co_{35}M_{10}$ (M = Si, Zr and Nb) amorphous alloys be potential materials for magnetic cooling operating in a wide temperature range from 150 to 175 K, e.g., as part of a gas liquefaction process.

Enhanced Crystallization of Amorphous Si Using viscous Ni Solution and Microwave Annealing

  • Ahn, Jin-Hyung;Eom, Ji-Hye;Ahn, Byung-Tae
    • Journal of Information Display
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    • 제2권2호
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    • pp.7-12
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    • 2001
  • A viscous Ni solution was coated over amorphous Si thin film for evenly spread of Ni metal source. The Ni s. prepared by dissolving $NiCl_2$ into IN HCI and mixing with propylene glycol. $NiCl_2$ and Ni were deposited on the amorphous film after oven dry and they enabled to obtain a uniform crystallization. The crystallization using the viscous Ni solution was a Ni-silicide mediated process, the same process used with Ni metal layer. The crystallization temperature was lowered to $480^{\circ}C$ by the synergy effect of silicide-mediated crystallization and microwave-induced crystallization. Lateral crystallization was also enhanced such that the velocity of lateral crystallization by microwave annealing became faster than by furnace annealing.

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Studies on Nanostructured Amorphous Carbon by X-ray Diffraction and Small Angle X-ray Scattering

  • Dasgupta, K.;Krishna, P.S.R.;Chitra, R.;Sathiyamoorth, D.
    • Carbon letters
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    • 제4권1호
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    • pp.10-13
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    • 2003
  • The structural studies of amorphous isotropic carbon prepared from pyrolysis of phenol formaldehyde resin have been carried out using X-ray diffraction. X-ray diffraction from as prepared sample at $1000^{\circ}C$ and a sample treated at $1900^{\circ}C$ revealed that both are amorphous even though there are small differences in short range order. It is found that both are graphite like carbon (GLC) with predominantly $sp^2$ hybridization. Small angle X-ray scattering results show that as prepared sample mainly consists of thin two dimensional platelets of graphitic carbon whereas they grow in thickness to become three dimensional materials of nano dimensions.

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Crystallization Behavior of Ti-(50-x)Ni-xCu(at%) (x = 20-30) Alloy Ribbons

  • Kim, Min-Su;Jeon, Young-Min;Im, Yeon-Min;Lee, Yong-Hee;Nam, Tae-Hyun
    • Transactions on Electrical and Electronic Materials
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    • 제12권1호
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    • pp.20-23
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    • 2011
  • Amorphous Ti-(50-x)Ni-xCu (at%) (x = 20, 25, 27, 30) alloy ribbons were prepared by melt spinning. Subsequently, the crystallization behavior of the alloy ribbons was investigated by X-ray diffraction and differential scanning calorimetry. ${\Delta}T$ (the temperature gap between $T_g$ and $T_x$) increased from 33 K to 47 K and the wavenumber ($Q_p$) decreased from 29.44 $nm^{-1}$ to 29.29 $nm^{-1}$ with increasing Cu content from 20 at% to 30 at%. The activation energy for crystallization decreased from 188.5 kJ/mol to 170.6 kJ/mol with increasing Cu content from 20 at% to 25 at%; afterwards, the activation energy remained near constant. Crystallization occurred in two-stage: amorphous-B2-$TiCu_2$ in Ti-Ni-Cu alloys with Cu content less than 25 at%, while it occurred in three-stage; amorphous-B2-TiCu-$TiCu_2$ in Ti-Ni-Cu alloys with Cu content more than 27 at%.