• Title/Summary/Keyword: ultraviolet ray

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The growth of ZnO nanorods by hydrothermal method on organic substrates (유기 기판 위에 수열 합성법으로 성장된 ZnO 나노 막대의 특성 연구)

  • Kim, Ah-Ra;Lee, Ji-Yeon;Lee, Ju-Young;Kim, Hong-Seung;Park, Hyun-Kook
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.281-281
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    • 2010
  • In this study, ZnO nanorod arrays are grown on organic substrates by hydrothermal method which requires a low temperature, simple process, and no vacuum. The structure properties of ZnO nanorods were examined by field emission scanning electron microscopy and X-ray diffraction. To detect the optical transmission, ultraviolet visible spectrophotometer was also used. From results, the ZnO nanorods were grown the horizontal growth on the organic substrates had the length of over $10\;{\mu}m$. After deposition of ZnO seed layer, the ZnO nanorod arrays had uniformity orientation and length.

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Low temperature UV-assisted rapid thermal processing of (Ba,Sr)$TiO_3$ thin films (저온에서 (Ba,Sr)$TiO_3$ 박막의 UV를 이용한 RTP에 관한 연구)

  • Cho, Kwang-Hwan;Kang, Chong-Yun;Yoon, Seok-Jin;Lee, Young-Pak
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.234-234
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    • 2008
  • Chemically homogeneous $Ba_{0.6}Sr_{0.4}TiO_3$ (BST) sols were synthesized using barium acetate, strontium acetate, and titanium isoproxide as starting materials. BST thin films of thickness 340 nm were deposited on Pt/$TiO_2/SiO_2$/Si and alumina substrates using spin coating method. The technique used for the processing of these films was Ultraviolet (UV) sol-gel photoannealing, using phto-sensitivity precursor solutions and UV-assisted rapid thermal processing(UV-RTP). The crystallization behaviour of the BST sols and thin films was studied by differential thermal analysis (DTA) and X-ray diffraction (XRD). Variation of permittivity and dielectric loss were measured in LCR-meter, model HP 4394A.

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Evaluation of Maintenance Coating Materials for Steel Bridges

  • Lee, Chan-Young;Cheong, Haimoon;Kim, Ok-Sun
    • Corrosion Science and Technology
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    • v.4 no.5
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    • pp.207-210
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    • 2005
  • Coating performance of various coating systems including chlorinated rubber and epoxy/urethane used most for steel structures of highway in Korea, was evaluated by exposing test specimen to complex deterioration factors such as ultraviolet ray, moisture, freeze-thaw cycle and salt. Deteriorated specimens were evaluated by chalking and rust grades according to ASTM, and measurement of color differences and adhesion. In overall coating performances such as corrosion resistance, photochemical stability, and adhesion, ceramic/ urethane, moisture-curable urethane/ urethane, etc. were superior. As for other coating materials tested in this study, superior materials against certain deterioration factors may be inferior against other factors. Accordingly, in order to select suitable maintenance coating materials for the use, it is thought that investigation of suitability through experiment should precede selection of materials, especially for unusual coatings or paints.

FUV Emission-line Morphologies of the SNR G65.3+5.7

  • Kim, Il-Joong;Seon, Kwang-Il;Min, Kyoung-Wook
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.70.1-70.1
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    • 2010
  • We present the far-ultraviolet (FUV) emission line morphologies in the whole region of the supernova remnant G65.3+5.7 using the FIMS/SPEAR data. The morphologies of the C IV ${\lambda}{\lambda}1548$, 1551, $H2{\lambda}1608 $, He II ${\lambda}1640$, and O III] ${\lambda}{\lambda}1661$, 1666 lines appear to correlate clearly with the optical emission line images or the ROSAT X-ray (0.11-0.284 keV) image obtained in some of the previous studies. We found that a foreground dust cloud, resonant scattering, and incompleteness of radiative shocks have made the definite differences between the morphologies of the above FUV emission lines. We also present the FUV spectra and line intensities from a few sub-regions.

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A study on the Electric Characteristics of Polyimide Ultra Thin through LB-Method (Langumir-Blodgett법으로 제작된 polyimide 超薄膜(초박막)의 전기적특성(電氣的特性))

  • Park, Sang-Hyun;Yun, Sung-Do;Cheong, Hak-Su;Kook, Sang-Hoon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1992.11a
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    • pp.63-66
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    • 1992
  • Using an aromatic system, we made a ultra thin insulator through LB-method. We measured and wrote down afternating currant characteristics of ultraviolet rays extincting-spectrum and I.R extincting-spectrum. We surveyed the thickness of a film through X-ray diffracting method and certified about $4{\AA}$ by the layer. Measuring the characteristics of direct current voltage and electric current with this sample, we produced its conductivity and discovered that this sample had a god insulating performance. Addition to this, we measured the characteristics of voltage and electric current, and the temperature dependency of conductivity in a high voltage system and with these results tried to interpret a mechanism of conduction.

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Correlation between Ferromagnetic State and Thermally Stable Layer of Fe on the W(001) Surface

  • Sin, Min-Jeong;Park, Byeong-Gyu;Hwang, Chan-Yong;Lee, Han-Gil
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.173.1-173.1
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    • 2014
  • The variations of electronic and magnetic properties of ultrathin Fe overlayers on a W(001) surface as a function of Fe film thickness (1.0~4.0 ML) has been investigated using x-ray magnetic circular dichroism (XMCD) in conjunction with ultraviolet photoelectron spectroscopy (UPS) and low energy electron diffraction (LEED). We found that the ferromagnetic property of Fe film started to build up over 2.0 ML, as we confirmed the spin and angular moment contribution to the magnetic moment using XMCD experiments. We will systematically demonstrate that the occurrence of ferromagnetic property of Fe film on a W(001) surface is closely correlated to a themally stable layer of Fe film on a W(001) surface.

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Optical Reactivity Modification of Titanium Oxide coatings on Ceramic filters by Nitrogen ion Implantation

  • Kim, Hyeong-Jin;Park, Jae-Won
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.90-90
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    • 2010
  • We investigated the modification of optical response properties of titanium dioxide (TiO2) coatings on the ceramic water-purification filters by using ultraviolet-visible absorption spectroscopy and X-ray diffraction. The TiO2 coatings were prepared on ceramic substrate by e-beam evaporation method. These amorphous TiO2 were turned into anatase phase by heat treatment at $700^{\circ}C$ for 2 hours. The doping of N atoms into the TiO2 coatings was done by using 70KeV of N+ ion implantation with the dose of $1.0{\times}1017$ ions/cm2, followed by post-irradiation heat treatment at $550^{\circ}C$ for 2 hours. Methylene blue test of TiO2 coatings to solar irradiation showed that the post-evaporation heated TiO2 was photocatalytic and N-doped TiO2 reacted to the visible part of solar irradiation.

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Fabrication of Hybrid Films Using Titanium Chloride and 2,4-hexadiyne-1,6-diol by Molecular Layer Deposition

  • Yun, Gwan-Hyeok;Seong, Myeong-Mo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.418-418
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    • 2012
  • We fabricated a new type of hybrid film using molecular layer deposition (MLD). The MLD is a gas phase process analogous to atomic layer deposition (ALD) and also relies on a saturated surface reaction sequentially which results in the formation of a monolayer in each sequence. In the MLD process, polydiacetylene (PDA) layers were grown by repeated sequential surface reactions of titanium tetrachloride and 2,4-hexadiyne-1,6-diol with ultraviolet (UV) polymerization under a substrate temperature of $100^{\circ}C$. Ellipsometry analysis showed a self-limiting surface reaction process and linear growth of the hybrid films. Polymerization of the hybrid films was confirmed by infrared (IR) spectroscopy and UV-Vis spectroscopy. Composition of the films was confirmed by IR spectroscopy and X-ray photoelectron (XP) spectroscopy. The titanium oxide cross-linked polydiacetylene (TiOPDA) hybrid films exhibited good thermal and mechanical stabilities.

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The interfaces between Alq3 and ZnO substrates with various orientations

  • Lee, Jeong-Han;Lee, Yeon-Jin
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.343-343
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    • 2011
  • ZnO has been introduced as one of the good candidates for next generation opto-electronics. Recently, ZnO is known to be suitable for the transparent electrode in organic solar cells and light emitting devices. The contact with n-type organic material has been studied due to the n-type properties of ZnO. However, the surface of ZnO has shown different electronic property with respect to its surface orientation. Therefore, it is presumed that there are differences in the interfacial electronic structures between organic materials and ZnO with different orientation. Therefore, it is required to classify the interfacial electronic structures according to the surface orientation of ZnO. In this study, we measured the interfacial electronic structures between the ZnO substrate having various orientations and a typical n-type organic material, tris-(8-hydroxyquinoline) aluminum (Alq3). In-situ x-ray and ultraviolet photoelectron spectroscopy measurements revealed the interfacial electronic structures. We found the changes in the electronic structures with respect to the orientation of ZnO substrate and it could be used to improve the contact between ZnO and Alq3.

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Gas Sensing Properties of Au-decorated NiO Nanofibers (Au 촉매금속이 첨가된 NiO 나노섬유의 가스 검출 특성)

  • Kang, Wooseung
    • Journal of the Korean institute of surface engineering
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    • v.50 no.4
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    • pp.296-300
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    • 2017
  • NiO nanofibers with Au nanoparticles were synthesized by sol-gel and electrospinning techniques, in which the reduction process by ultraviolet exposure is included for the growth of Au nanoparticles in the electrospinning solution. FE-SEM(Field Emission Scanning Electron Microscopy), TEM(Transmission Electron Microscopy) revealed that the synthesized nanofibers had the diameter of approximately 200 nm. X-ray diffraction showed the successful formation of Au-decorated NiO nanofibers. Gas sensing tests of Au-decorated NiO nanofibers were performed using reducing gases of CO, and $C_6H_6$, $C_7H_8$, $C_2H_5OH$. Compared to as-synthesized NiO nanofibers, the response of Au-loaded NiO nanofibers to CO gas was found to be about 3.4 times increased. On the other hand, the response increases were only 1.1-1.3 times for $C_6H_6$, $C_7H_8$, and $C_2H_5OH$.