• Title/Summary/Keyword: X-ray spectroscopy

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Photoelectron spectro-microscopy/Scanning photoelectron microscopy (SPEM) (광전자 분광현미경학)

  • Shin, Hyun-Joon
    • Vacuum Magazine
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    • v.3 no.4
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    • pp.8-13
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    • 2016
  • The need of space-resolved x-ray photoelectron spectroscopy (XPS) has developed scanning photoelectron microscopy (SPEM). SPEM provides space-resolved XPS data from a spot of a sample as well as images of specific element, chemical state, valency distribution on the surface of a sample. Based on technical advancement of tight x-ray focusing, sample positioning accuracy, and electron analyzer efficiency, SPEM is now capable of providing ~100 nm space resolution for typical XPS functionality, and SPEM has become actively applied for the investigation of chemical state, valency, and electronic structure on the surface of newly discovered materials, such as graphene layers, dichalcogenide 2D-materials, and heterogenous new functional materials.

Staining Properties of Waterborne PU Membranes (수분산 PU막의 염색 오염성)

  • 정동석;이문철
    • Textile Coloration and Finishing
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    • v.15 no.5
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    • pp.285-293
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    • 2003
  • Waterborne PU membrane was prepared from waterborne PU dispersion solution to investigate physical and staining properties. The staining properties of waterborne PU membrane with acid dyes and disperse dyes were observed. The physical properties of the PU membrane were investigated by X-ray diffraction and IR spectroscopy. The staining property of waterborne PU membrane for azo acid dyes is better than that of disperse dyes. X-ray diffraction peaks sharpened and tensile strain and stress increased with heat setting temperature.

1-D and 2-D Metal Oxide Nanostructures

  • Son, Yeong-Gu
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.87-88
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    • 2012
  • Metal oxide nanostructures have been applied to various fields such as energy, catalysts and electronics. We have freely designed one and two-dimensional (1 and 2-D) metal (transition metals and lanthanides) oxide nanostructures, characterized them using various techniques including scanning electron microscopy, transmission electron microscopy, X-ray diffraction crystallography, thermogravimetric analysis, FT-IR, UV-visible-NIR absorption, Raman, photoluminescence, X-ray photoelectron spectroscopy, and temperature-programmed thermal desorption (reaction) mass spectrometry. In addition, Ag- and Au-doped metal oxides will be discussed in this talk.

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Progress Report on Optical Spectroscopy of X-ray selected Intermediate-mass Black Holes

  • Kim, Minjin;Ho, Luis C.
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.1
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    • pp.42.2-42.2
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    • 2014
  • We present high-resolution optical spectra of newly selected candidates of intermediate-mass black holes. The sample was selected based on the variability and spectral shape in X-ray. The spectra was taken with Magellan 6.5 m Clay Telescope and cover the rest-frame region 3500-10000A. The high spectral resolution (R~4000) of the spectrum allows us to estimate BH masses of the sources. Interestingly, the majority of the sample appears to have broad emission lines. Using this dataset, we will estimate the BH masses and Eddington ratio in order to understand their physical properties.

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Investigation of Molybdenum Oxide Thin Films for CIGS Applications

  • Bin, Jun-Hyeong;Park, Ju-Yeon;Gang, Yong-Cheol
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.388-388
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    • 2010
  • Molybdenum oxide thin films were deposited on p-type Si(100) by an RF magnetron sputtering method. The physical and chemical properties of these films were studied with X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. The thickness of molybdenum oxide thin films was measured by spectroscopic ellipsometer (SE) and the thickness was about 200 nm. As the oxygen gas pressure increased, the thickness was decreased, the phases of the thin films were changed, and the amount of metallic Mo decreased but the contents of $Mo^{6+}$ species increases.

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A New Porous Carbon via an Exfoliation of n-Octylammonium Tetrachloroferrate(III)-Graphite Intercalation Complex

  • 권채원;김동훈;최진호
    • Bulletin of the Korean Chemical Society
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    • v.19 no.10
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    • pp.1113-1116
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    • 1998
  • A new graphite intercalation compound (GIC), n-octylammonium tetrachlorofeffate(Ⅲ)-graphite, has been derived from well-known ferric chloride graphite intercalation compound. X-ray diffration study shows that the basal spacing of this new GIC is 20.8 Å. In order to investigate the local geometry around the iron atom in the graphite layers, X-ray absorption spectroscopy experiments were performed. The first discharge capacity of its exfoliated form is found to be 862 mAh/g, which is more than double the value of pristine graphite (384 mAh/g). Such a drastic increase implies that the exfoliated graphite is a promising electrode material.

Synthesis and Physical Properties of Sm Doped Pb Free 3 Phase-Glasses (Sm 농도에 따른 무연 3상 유리계의 합성과 물리적 성질)

  • Park, Jong-Ho
    • Korean Journal of Materials Research
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    • v.22 no.7
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    • pp.368-373
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    • 2012
  • Glasses were prepared with compositions of $(13-x)BaO-80B2_O_3-7Li_2O{\cdot}xSm_2O_3$, BBLSx(x=0.5, 0.4, 0.3) by melting the starting materials of boron oxide(99.9%), lithium oxide(99.9%), barium carbon oxide(99.9%), and samarium oxide(99.9%) and then quenching the melt at $1350^{\circ}C$. This led to good-quality BBLSx(x=0.4, 0.3) and poor-quality BBLSx(x=0.5) glasses. The physical and structural properties of the BBLSx glasses were studied by means x-ray diffraction, scanning electron microscopy(SEM), differential scanning calorimetry(DSC), and dielectric spectroscopy. From the x-ray diffraction and SEM results, the quality of the BBLSx glasses significantly depends on the $Sm_2O_3$ concentration. The x-ray diffraction pattern showed that the crystallites in the BBLSx glasses after heat treatment at $700^{\circ}C$ may be $LiBaB_9O_{15}$. From the DSC results, the glass transition temperatures($T_g$), crystallization temperatures($T_c$), and the maximum temperatures of the crystallized($T_p$) BBLSx glasses all changed with the $Sm_2O_3$ concentration. According to the dielectric spectroscopy results, the values of the real dielectric constant and Tan ${\delta}$ of the BBLSx glasses depended on the $Sm_2O_3$ concentration. The values of the real dielectric constant and Tan ${\delta}$ were also shown to depend on the measuring temperature, possibly due to the ion migration in the bulk of the BBLSx glasses.

Study on Methods of Enhancement and Measurement of Corrosion Resistance for Subsea Equipment made of Aluminum (알루미늄으로 제작된 심해 장비의 부식 저항 능력 향상 방법 및 측정 방법 조사)

  • Seo, Youngkyun;Jung, Jung-Yeul
    • Plant Journal
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    • v.16 no.3
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    • pp.47-52
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    • 2020
  • This study investigated the methodologies to enhance the corrosion resistance and the ways to measure for subsea equipment made of aluminum. The methodologies for the anticorrosion were cathodic protection, conversion coating, anodizing and organic coating. The simply analyzed ways to measure the corrosion resistance were Scanning Electron Microscope (SEM), Electrochemical Impedance Spectroscopy (EIS), Glow discharge optical emission spectrum spectroscopy (GD-OES), Fourier Transform Infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), Scanning Vibrating Electrode Technique (SVET), contact angle and interfacial tension. The most widely used tools for increasing the corrosion resistance were the anodizing and the organic coating. Many ways were evenly used to measure corrosion. The methods more frequently utilized were SEM for the surface investigation and the contact angle to evaluate the corrosion resistance.

CHANDRA SPECTROSCOPY OF SUPERNOVA REMNANT 3C 391

  • CHEN YANG;SU YANG;SLANE PATRICK O.;WANG Q. DANIEL
    • Journal of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.211-214
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    • 2005
  • We performed a spatially resolved spectroscopic study of the thermal composite supernova remnant 3C 391 by the Chandra observation. Broad- and narrow-band X-ray images show a southeast-northwest elongated morphology and unveil a highly clumpy structure of the remnant. The spectral analysis for. the small-scale features indicates normal metal abundance and uniform temperature for the interior gas. The properties of the hot gas are largely in agreement with the cloudlet evaporation model as a main mechanism for the 'thermal composite' X-ray appearance, though radiative rim and thermal conduction may also be effective. An unresolved X-ray source, with a power-law spectrum, is observed on the northwest border. The equivalent width images reveal a faint finger-like protrusion in Si and S lines out of the southwest radio border.

A modified electrode by a facile green preparation of reduced graphene oxide utilizing olive leaves extract

  • Baioun, Abeer;Kellawi, Hassan;Falah, Ahamed
    • Carbon letters
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    • v.24
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    • pp.47-54
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    • 2017
  • Different phytochemicals obtained from various natural plant sources are used as reduction agents for preparing gold, copper, silver and platinum nanoparticles. In this work a green method of reducing graphene oxide (rGO) by an inexpensive, effective and scalable method using olive leaf aqueous extract as the reducing agent, was used to produce rGO. Both GO and rGO were prepared and investigated by ultraviolet and visible spectroscopy, Fourier-transform infrared, scanning electron microscopy, atomic force microscopy, thermogravimetric analysis, cyclic voltammetry, X-ray photoelectron spectra, electrochemical impedance spectroscopy and powder X-ray diffraction.