• Title/Summary/Keyword: XPS.

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The Effects of 2nd Metals in Pt-based Electrocatalysts on Methanol Oxidation (Pt합금 촉매에서 메탄을 산화 반응에 미치는 제2금속의 영향)

  • Kim Yeong Min;Park Gyeong Won;Choi Jong Ho;Park In Su;Seong Yeong Eun
    • 한국전기화학회:학술대회논문집
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    • 2002.07a
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    • pp.179-182
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    • 2002
  • The electrooxidation of methanol was studied using Pt, PtRu(1:1), PtNi(1:1), PtRh(1:1) and PtOs(1:1) alloy nanoparticles for application as electrocatalysts. The effects of the second metals in the electrocatalytic activity was investigated using cyclic voltammetry (CV), chronoamperometry (CA), X-ray photoelectron spectroscopy (XPS). There are the metallic and oxygen states in the PtRu and PtOs electrocatalysts . In the XPS of PtRu and PtOs alloy nanoparticles, the oxygen sources were dominant as the second metal's effects. Negative shifts of the binding energies of Pt for the PtNi, PtRh alloy nanoparticles were determined by XPS measurements, which can be explained by electronic effects.

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Analysis of the Surface Degradation in UV-irradiated Poly(ethylene terephthalate) films (자외선 조사된 Poly(ethylene terephthalate) 필름의 표면 열화 분석)

  • Lim, Kyung-Bum;Kim, Jong-Yoon;Choi, Hoon-Young
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.12
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    • pp.2230-2234
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    • 2010
  • This paper deals with the change of surface potential decay, surface resistivity, contact angle and XPS of ultraviolet-treated PET films. From the experimental results on the surface potential decay of UV degraded-samples, it was found that the accumulation of charge is decreased and the surface potential decay time is shortened. Also, from the result of XPS, it was found that the changes affected by the surface degradation of PET film were caused by the generation of carboxyl groups through the chain decomposition and recombination with oxygen molecules in the air.

A Study on the Etching Mechanism of (Ba,Sr)$TiO_3$ Thin Films using MEICP (MEICP에 의한 (Ba,Sr)$TiO_3$ 박막의 식각 메커니즘에 관한 연구)

  • Min, Byung-Jun;Kim, Chang-Il
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.04b
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    • pp.52-55
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    • 2000
  • In this study, (Ba,Sr)$TiO_3$(BST) thin films were etched with a magnetically enhanced inductively coupled plasma(MEICP) as a function Ar/$CF_4$ gas mixing ratio. Experiment was done by varying the etching parameters such as rf power, dc bias voltage and chamber pressure. The maximum etch rate of the BST films was 1700 ${\AA}/min$ under $CF_4/(CF_4+Ar)$ of 0.1, 600 W/350 V and 5 mTorr. The selectivity of BST to Pt and PR was 0.6, 0.7, respectively. X -ray photoelectron spectroscopy(XPS) studies shows that there are surface reaction between Ba, Sr, Ti and C, F radicals during the etching. To analyze the composition of surface residue remaining after the etching, films etched with different $CF_4$/Ar gas mixing ratio were investigated using XPS.

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Etching Characteristics BST Thin Film in $CF_4$/Ar Plasma ($CF_4$/Ar 플라즈마에 의한 BST 박막 식각 특성)

  • 김동표;김창일;서용진;이병기;장의구
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.866-869
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    • 2001
  • In this study, (Ba,Sr)TiO$_3$(BST) thin films were etched with a magnetically enhanced inductively coupled plasma(MEICP). Etching characteristics of BST thin films including etch rate and selectivity were evaluated as a function of the etching parameters such as gas mixing ratio, rf power, dc bias voltage and chamber pressure. The maximum etch rate of the BST films was 1700 $\AA$/min at Ar(90)/CF$_4$(10), 600 W/350 V and 5 mTorr. The selectivity of BST to PR was 0.6, 0.7, respectively. To analyze the composition of surface residue remaining after the etching, samples etched with different CF$_4$/Ar gas mixing ratio were investigated with X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). From the results of XPS and SIMS, there are chemical reaction between Ba, Sr, Ti and C, F radicals during the etching and remained on the surface.

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Preparation of Tantalum Anodic Oxide Film in Citric Acid Solution - Evidence and Effects of Citrate Anion Incorporation

  • Kim, Young-Ho;Uosaki, Kohei
    • Journal of Electrochemical Science and Technology
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    • v.4 no.4
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    • pp.163-170
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    • 2013
  • Tantalum anodic oxide film was prepared in citric acid solution of various concentrations and the prepared Ta anodic oxide film was characterized by various electrochemical techniques and X-ray photoelectron spectroscopy (XPS). The prepared Ta anodic oxide film showed typical n-type semiconducting properties and the dielectric properties were strongly dependent on the citric acid concentration. The variation of electrochemical and electronic properties was explained in terms of electrolyte anion incorporation into the anodic oxide film, which was supported by XPS measurements.

An XPS Study of Oxyfluorinated Multiwalled Carbon Nano Tubes

  • Yun, Seok-Min;Kim, Ju-Wan;Jung, Min-Jung;Nho, Young-Chang;Kang, Phil-Hyun;Lee, Young-Seak
    • Carbon letters
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    • v.8 no.4
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    • pp.292-298
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    • 2007
  • In order to investigate functional groups on the surface of Multi-walled Carbon Nanotubes (MWCNTs) induced by oxyfluorination, XPS (X-ray photoelectron spectroscopy) analysis was carried out. All core level spectra of MWCNTs were deconvoluted to several Pseudo-Voigt functions (sum of Gaussian-Lorentzian functions). Both O1s and F1s binding energy of oxyfluorinated MWCNTs shifted high value as increment of fluorine mixing ratio. The carbon-fluorine covalent bonding concentration increased as increment of fluorine mixing ratio. The shape and intensity of OF10-MWCNTs are similar with those of as-received MWCNTs. However, the intensity and binding energies of main peak position of OF20-MWCNTs and OF30-MWCNTs were dramatically increased by oxyfluorination.

Adsorption mechanism of copper ions on porous chitosan membranes: Equilibrium and XPS study

  • Ghaee, Azadeh;Zerafat, Mohammad Mahdi
    • Membrane and Water Treatment
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    • v.7 no.6
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    • pp.555-571
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    • 2016
  • Heavy metal contamination has attracted considerable attention during recent decades due to the potential risk brought about for human beings and the environment. Several adsorbent materials are utilized for the purification of contaminated water resources among which chitosan is considered as an appropriate alternative. Copper is a heavy metal contaminants found in several industrial wastewaters and its adsorption on porous and macroporous chitosan membranes is investigated in this study. Membranes are prepared by phase inversion and particulate leaching method and their morphology is characterized using SEM analysis. Batch adsorption experiments are performed and it is found that copper adsorption on macroporous chitosan membrane is higher than porous membrane. The iso-steric heat of adsorption was determined by analyzing the variations of temperature to investigate its effect on adsorption characteristics of macroporous chitosan membranes. Furthermore, desorption experiments were studied using NaCl and EDTA as eluants. The mechanism of copper adsorption was also investigated using XPS spectroscopy which confirms simultaneous occurrence of chelation and electrostatic adsorption mechanisms.

REVIEW OF REACTION-TO-FIRE REQUIREMENTS' APPLICATION IN EU & NON-EU BASED ON XPS INSULATION (유럽 및 비유럽권역의 REACTION-TO-FIRE에 대한 XPS 관련 규정 적용성 검토)

  • Park, Kye-Won;Jeong, Jae-Gun;Thureson, Per
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 2011.04a
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    • pp.127-130
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    • 2011
  • This paper is about an recent overview of the fire regulations of several countries as for the use of XPS related insulation in building application. The data compiled in this paper is based both on in-house expertise at SP Fire Technology, in particular in relation to European Building legislation, and on replies to a questionnaire distributed to a selected group of colleagues internationally, and subsequent discussions with these colleagues.

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Tribochemical Mechanism of Borate of Triethanolamine in Water Solution by XPS

  • Du, Da-Chang;Kim, Seock-Sam;Suh, Chang-Min
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.11a
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    • pp.374-379
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    • 2001
  • Tribochmical behaviors of a borate of triethanolamine in water solution were evaluated using a four-ball wear tester. X-ray photoelectron spectroscopy (XPS) was employed to study tribochemical species on worn scars of steel balls. Results show that a thick deposit layer was produced on the worn scars, which came from the decomposition of the borate. The surface film on the worn scars was mostly consisted with H$_{3}$BO$_{3}$, B$_{2}$O$_{3}$ and large amounts of ferricyanides.

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Characterization of Surface Oxides in Gold Thin Films with V- and Ti- underlays by AES and XPS (AES/XPS를 이용한 Au/V, Au/Ti 박막의 표면산화물 분석)

  • Kim, Jin -Young
    • Journal of the Korean Vacuum Society
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    • v.1 no.1
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    • pp.100-105
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    • 1992
  • Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) analyses have been performed on double-structured Au/V and Au/Ti thin films after heat treatment at 500$^{\circ}$C in air. V- and Tiunderlays sandwiched between gold thin films and SiOz substrates form oxides on the free surface of gold films during the heat treatment. The chemical compositions of the oxides were identified as V205 and TiOz in Au/V and Au/Ti thin films, respectively.

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