• Title/Summary/Keyword: preparation technique

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The Study on Characteristics of High Frequency Glow Discharge in Organic Vapor (유기 가스중 고주파 글로우가전 특성에 관한 연구)

  • 이덕출;김은배;박상현;박종대
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.34 no.9
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    • pp.355-360
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    • 1985
  • In this paper, the discharge phenomena of high frequency glow discharge in organic vapor are basically investigted to establish the growth mechanism and preparation technique for organic thin film. According to the increasing of discharge frequency, the discharge firing voltage(Vs) of organic vapor decreases. The dependence of discharge voltage(Vd) on gas pressure is generally in accord with Paschen's Law and Vd decreases as gas flow rate become larger, but increases as dischange current density become higher. And the values of Vd in organic vapor are generally higher than those of inorganic gas.

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Preparation of Polycrystalline Mullite Fiber Using the Sol-Gel Technique (졸-겔법에 의한 다결정 물라이트 섬유의 제조)

  • 김경용;김윤호;이수원;정형진;김구대
    • Journal of the Korean Ceramic Society
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    • v.26 no.6
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    • pp.795-801
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    • 1989
  • The polycrystalline mullite fiber was synthesized from various combination of starting materials including metal alkoxides and colloidal sol by the sol-gel process. The best spinnability was observed in the sol which showed shear thinning and hysteresis (i.e., thixotropic flow), indicating that the network structure was broken down as the shear rate increased. The mullite fiber was polycrystalline after firing and characterized by thermal analysis, XRD, FT-IR spectroscopy, rheological measurements, and SEM.

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Synthesis, Characterization and Application of Poly(4-vinylpyridine)-Supported Brønsted Acid as Reusable Catalyst for Acetylation Reaction

  • Borah, Kalyan Jyoti;Dutta, Papia;Borah, Ruli
    • Bulletin of the Korean Chemical Society
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    • v.32 no.1
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    • pp.225-228
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    • 2011
  • Poly(4-vinylpyridine)-supported $Br{\phi}nsted$ acids (P4VP-HX) were prepared by wet impregnation technique. These supported acids were found as efficient heterogeneous green catalysts for acetylation of alcohol, amine and phenol with different catalytic activities. The wide application of P4VP-HX as reusable solid acid catalyst in organic reactions is possible because of its simple preparation and handling, stability, simple work up procedure.

Determination of Enalapril in Human Plasma by High Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry

  • Yoon, Kyung-Hwan;Kim, Won;Park, Jong-Sei;Kim, Hie-Joon
    • Bulletin of the Korean Chemical Society
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    • v.25 no.6
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    • pp.878-880
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    • 2004
  • Revered-phase LC-electrospray ionization mass spectrometry was used to selectively determine enalapril from plasma with minimal sample preparation. Detection limit of the method was 1 ng/mL. Precision (within day and between days) and accuracy of the method at various concentrations were acceptable. The analytical technique was used for pharmacokinetic studies after administration of enalapril to human test subjects.

Transnasal Esophagoscopy (경비 식도 내시경)

  • Park, Young-Hak;Kim, Hyun-Soo
    • Korean Journal of Bronchoesophagology
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    • v.16 no.2
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    • pp.91-96
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    • 2010
  • Transnasal esophagoscopy allows. the upper aerodigestive tract, from the nasal cavity to the gastric cardia to be examined in the outpatients department. It is well tolerated by patient with topical anesthesia alone and no sedation or patient preparation is required. The technique is easily learned and performed in the otolaryngologist and highly cost efficient. It is a useful tool for accurate diagnosis and can be used in a variety of office-based procedures.

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Effect of Annealing and Polymeric Additives on Permeation Properties of Asymmetric Polyacrylonitrile Membranes

  • Yoon, Joon-Ki;Bumsuk Jung;Rhee, Hee-Woo;Kang, Yong-Soo
    • Proceedings of the Membrane Society of Korea Conference
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    • 2004.05a
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    • pp.161-165
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    • 2004
  • Since Loeb and Souriajan first introduced phase inversion method [1], much investigation has been made for understanding the mechanism of formation of asymmetric membranes. Phase inversion is the most extensively used technique for the preparation of asymmetric membranes, which is that cast solution film on a substrate is immersed and is precipitated in water bath.(omitted)

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Atom Probe Tomography: A Characterization Method for Three-dimensional Elemental Mapping at the Atomic Scale

  • Choi, Pyuck-Pa;Povstugar, Ivan
    • Journal of Powder Materials
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    • v.19 no.1
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    • pp.67-71
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    • 2012
  • The present paper gives an overview about the Atom Probe Tomography technique and its application to powder materials. The preparation of needle-shaped Atom Probe specimens from a single powder particle using focused-ion-beam milling is described. Selected experimental data on mechanically alloyed (and sintered) powder materials are presented, giving insight into the atomic-scale elemental redistribution occurring under powder metallurgical processing.

Preparation and Property of Ceramic/Polymer 3-3 Composites with Matrices (각종 Matrix를 이용한 Ceramic/Polymer 3-3 Composies의 제작 및 특성)

  • Park, J.H.;SaGong, G.
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.1122-1124
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    • 1993
  • In this study, piezoceramics/polymer composites with 3-3 connectivity were made by BURPS(Burnout Plastic Sphere) technique with PZT ceramics and PVA sphere. And physical and dielectric properties dependent on the PVA wt.% were investigated. The density of porous piezoceramic and pieaoceramic/polymer composites were decreased almost linearly with increasing the PVA wt.%.

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