• Title/Summary/Keyword: SURFACE CRYSTALLIZATION

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Chalcogenide Ge-Sb-Se Optical and Crystallization Characteristics for Basic a Planning Aspheric Lens (비구면렌즈 설계를 위한 칼코게나이드 Ge-Sb-Se 광학계 및 결정화 특성 연구)

  • Myung, Tae Sik;Ko, Jun Bin
    • Korean Journal of Materials Research
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    • v.26 no.11
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    • pp.598-603
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    • 2016
  • The recent development of electro-optic devices and anticorrosion media has led to the necessity to investigate infrared optical systems with solid-solid interfaces of materials that often have the characteristic of amorphousness. One of the most promising classes of materials for those purposes seems to be the chalcogenide glasses. Chalcogenide glasses, based on the Ge-Sb-Se system, have drawn a great deal of attention because of their use in preparing optical lenses and transparent fibers in the range of 3~12 um. In this study, amorphous Ge-Sb-Se chalcogenide for application in an infrared optical product design and manufacture was prepared by a standard melt-quenching technique. The results of the structural, optical and surface roughness analysis of high purity Ge-Sb-Se chalcogenide glasses are reported after various annealing processes.

Variation of Functional Characteristics of Illite with Heat Treatment (소결온도에 따른 일라이트 기능성 변화)

  • Kim, Ho-Soo;Kim, Han-Il;Seo, Pan-Seok;Koo, Kyung-Wan;Han, Sang-Ok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.05c
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    • pp.117-121
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    • 2002
  • In this paper, the proper manufacturing method to the use of Illite with many application was studied. We confirmed merit of manufacturing and forming according as respective temperature. The variety of crystallization and surface was confirmed by X-ray diffraction(XRD) analysis and SEM. Then, we performed the experiments such as a antibiosis, a heavy metal adsorption and a gas deodorizaton to confirm the function of Illite. As a result, the adsorption of gas decreased according as the heat treatment of Illite, but the ability of antibiosis wasn't changed.

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Characteristics of $SnO_2$/a-Se/AI sample ($SnO_2$/a-Se/AI 소자의 특성)

  • 박계춘;정운조;유용택
    • Electrical & Electronic Materials
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    • v.7 no.1
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    • pp.7-14
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    • 1994
  • Structural and optical characteristics in $SnO_2$/a-Se/Al sample by aging variation and applying constant voltage had been investigated. a-Se was varied with monoclinic structure and its surface was greatly exchanged. Its capacitance was first decreased and then increased and its photo-current, photo-voltage and photo-capacitance were increased gradually with day and applying voltage. From the results, crystallization of a-Se and dopant trap level formation had been identified. Also, it was acknowledged $SnO_2$/a-Se/Al sample is useful in photovoltaic and solid thin film cell.

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Deformation Behavior of $CU_{54}Ni_6Zr_{22}Ti_{18}$ Bulk Amorphous Alloy during Multi-Pass Warm Rolling (동계 벌크 아몰퍼스의 다단 온간 압연시 변형 거동)

  • Park E. S.;Kim H. J.;Bae J. C.;Huh M. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.139-142
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    • 2005
  • Cu-Ni-Zr-Ti bulk amorphous thin strips were produced by multi-pass warm rolling of the amorphous powder at temperatures in the supercooled liquid region. Process variables for rolling of the bulk amorphous strips were properly controlled to prevent onset of crystallization and failure during rolling up to three passes. During rolling of the amorphous powder, both the deformation and densification took place and the newly developed surface on the deformed amorphous particles enhances the consolidation leading to an increase in the strength. The strain state during rolling was analyzed by FEM.

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Enhancement of Thermomechanical Properties of Poly(D, L-lactic-co-glycolic acid) and Graphene Oxide Composite Films for Scaffolds

  • Yoon, Ok-Ja;Sohn, Il-Yung;Kim, Duck-Jin;Lee, Nae-Eung
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.548-548
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    • 2012
  • Thermomechanical and surface chemical properties of composite films of poly(D, L-lactic-co-glycolic acid) (PLGA) were significantly improved by the addition of graphene oxide (GO) nanosheets as nanoscale fillers to the PLGA polymer matrix. Enhanced thermomechanical properties of the PLGA/GO (2 wt.%) composite film, including an increase in the crystallization temperature and reduction in the weight loss, were observed. The tensile modulus of a composite film with increased GO fraction was presumably enhanced due to strong chemical bonding between the GO nanosheets and PLGA matrix. Enhanced hydrophilicity of the composite film due to embedded GO nanosheets also improved the biocompatibility of the composite film. Improved thermomechanical properties and biocompatibility of the PLGA composite films embedded with GO nanosheets may be applicable to biomedical applications such as scaffolds.

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Thermomechanical Properties of Poly(D, L-actic-co-glycolic acid) and Graphene Oxide Nanocomposite for Scaffolds

  • Sohn, Il-Yung;Yoon, Ok-Ja;Kim, Duck-Jin;Lee, Nae-Eung
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.478-478
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    • 2011
  • The thermomechanical and surface chemical properties of nanocomposite of poly( D, L-actic-co-glycolic acid) (PLGA) were improved significant due to concentration of graphene oxide (GO) nanosheets as nanoscale fillers to PLGA film. Thermomechanical properties of the PLGA/GO (2wt.-%.) nanocomposite were decreased crystallization and melting temperature, weight loss. The storage and loss moduli of the nanocomposite were enhanced by chemical bonding between the oxygenated functional groups of the GO nanosheets and the polymer chains in the PLGA matrix. Enhanced hydrophilicity of nanocomposite caused by embedded GO nanosheets also improved for good biocompatibility. Our findings indicate that thermomechanical properties and biocompatibility of nanocomposite embedded with GO nanosheets are attractive candidates for use in biomedical applications such as scaffolds.

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The Durability Estimation of Crystalline PV Module according to Mechanical Stress (결정질 태양전지모듈의 외부 응력에 따른 장기적 내구성 예측)

  • Kim, Kyung-Soo;Kang, Gi-Hwan;Yu, Gwon-Jong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.35-36
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    • 2008
  • In this paper, we studied the long term durability estimation for crystalline photovoltaic module while exposing to mechanical stress. Solar cell and PV module have many different kinds of stresses from cell to module fabrication. For this reason, some solar cell shows micro crack that decrease crystallization. In here, we expose artificial mechanical load on surface of PV module. Through this, the periodic external force on PV module might give an negative effect. The further analysis is described in the following paper.

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Fabrication of TFTs by using Ink-Jet Printing Process with Poly(4-vinylphenol) Bank layer and TIPS-Pentacene Semiconductor

  • Kim, Se-Min;Kim, Min-Jung;Park, Jong-S.;Song, Chung-Kun
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.937-939
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    • 2009
  • In this paper, we report electrical properties of OTFTs made by ink-jet printing with polyvinylphenol (PVP) for bank layer and bis(triisopropylsilylenthynyl) pentacene (TIPS-pentacene) for semiconductor. We could achieve better crystallization and surface uniformity of TIPS pentacene by employing PVP bank layer. The OTFT with PVP bank layer exhibited an field-effect mobility of 0.18 $cm^2$/Vs, current on/off ratio of $2.09{\times}10^5$, and subthreshold slope of 0.42 V/decane.

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A Study of Mechanical characteristics of functional Autoclaved Lightweight Concrete (기능성 경량기포콘크리트의 물리적 특성에 관한 실험적 연구)

  • Kim, Soon-Ho;Kim, Hong-Yong
    • KIEAE Journal
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    • v.7 no.5
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    • pp.121-126
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    • 2007
  • This is the experimental study on the functional property of the light-weight concrete according to the mineral composite. According to the increase of the functional mineral, Autoclaved light-weight concrete (ALC) have a effect of high far infrared ray, deodorization, anion and change of chromaticity on D65 of light source. Compressive strength and change of specific gravity by foaming of Mixed Slurry in accordance with additive rates and Water. It chracterizes surface by SEM, chemical component and crystallization by XRD, XRF. the results of this experiment studied influences of ALC by functional minerals.

Preparation of Porous Graphite by Using Template of Co- and Ni-Magadiite (Co, Ni 마가다이트 주형을 이용한 다공성 흑연의 합성)

  • Jeong Soon-Yong
    • Journal of Powder Materials
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    • v.12 no.2 s.49
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    • pp.151-158
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    • 2005
  • Porous graphite was synthesized by removal of template in HF after pyrolysis of pyrolyzed fuel oil (PFO) at $900^{\circ}C$ using the template of Co or Ni intercalated magadiite. Porous graphite had a plate structure like template, and d-spacing value of about 0.7 nm. The extent of crystallization of porous graphite was dependent on the contents of Co or Ni intercalated in interlayer. It can be explained that the metal such as Co and Ni acts as a promotion catalyst for graphite formation. Porous graphite shows the surface area of $328\sim477 m^2/g$.