• Title/Summary/Keyword: the source materials

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Preparation and Characterization of Carbon Nanofiber from Liquid Phase Carbon Source (액상법에 의한 Carbon Nanofiber 제조 및 특성 분석)

  • Lee, Won-Woo;Shin, Chae-Ho;Park, Han-Sung;Choi, Young-Min;Ryu, Beyong-Hwan
    • Korean Journal of Materials Research
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    • v.18 no.10
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    • pp.564-570
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    • 2008
  • Nanostructured carbon materials have been found to have applications in fuel cell electrodes, field emitters, electronic devices, sensors and electromagnetic absorbers, etc. Especially, the CNF (carbon nanofiber) can be expected to play an important role in catalyst supporters for fuel cell electrodes and chemical reactions. In this study, we synthesized CNF from a liquid phase carbon source by a solvothermal method. In addition, we studied the parameters for the preparation of CNF by controlling heating and cooling rates, synthesis temperature and time. We characterized the CNF by SEM/TEM, XRD, Raman spectroscopy and EDS. We found that the heating and cooling rate have strong effects on the CNF formation and growth. We were able to prepare the best CNF at the heating rate of $10^{\circ}$/min, at $450^{\circ}$ for 60 minutes, and at the cooling rate of $4^{\circ}$/min. As a result of Raman spectra, we found that the sample showed two characteristic Raman bands at ${\sim}1350cm^{-1}$ (D band) and ${\sim}1600cm^{-1}$ (G band). The G band indicates the original graphite feature, but the D band has been explained as a disorder feature of the carbon structure. The diameter and length of the CNF was about $15{\sim}20nm$, and over $1{\mu}$, respectively.

Advanced Materials Delivery Successes in CVD Processing

  • Loan, James F.
    • Journal of the Korean Vacuum Society
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    • v.4 no.S1
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    • pp.40-68
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    • 1995
  • As silicon divice geometrics become smaller and aspect ratios larger, processing technoloty is moving from PVD into the area of CVD and OMCVD. Many new source materials are in the research and development stage, and have placed challenging demands on materials delivery technology. This paper will describe the many successes achieved with various delivery methods including thermal, bubblers, pressure-based and Direct Liquid Injection.

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Scientific and Engineering Applications of Full-field Swept-source Optical Coherence Tomography

  • Mehta, Dalip Singh;Anna, Tulsi;Shakher, Chandra
    • Journal of the Optical Society of Korea
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    • v.13 no.3
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    • pp.341-348
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    • 2009
  • We report the development of full-field swept-source optical coherence tomography (SS-OCT) in the wavelength range of 815-870 nm using a unique combination of super-luminescent diode (SLD) as broad-band light source and acousto-optic tunable filter (AOTF) as a frequency-scanning device. Some new applications of full-field SS-OCT in forensic sciences and engineering materials have been demonstrated. Results of simultaneous topography and tomography of latent fingerprints, silicon microelectronic circuits and composite materials are presented. The main advantages of the present system are completely non-mechanical scanning, wide-field, compact and low-cost.