• Title/Summary/Keyword: x-ray diffraction(XRD)

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Zn/HA Coating on the Ti-xNb Alloys after Nanotube Formation for Dental Implant

  • Byeon, In-Seop;Choe, Han-Cheol
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2015년도 추계학술대회 논문집
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    • pp.139-140
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    • 2015
  • Zn/HA coating on the Ti-xNb alloys after nanotube formation for dental lmplant was researched using various experimental methods. Due to g ood biocompatibility and osteoconductivity, hydroxyapatite (HA) coating s on metallic biomedical implants were widely employed in orthopedic and dental applications. To improve biocompatibilities, Zinc (Zn) plays very important roles in the bone formation and immune reg ulations. The nanotube formed Zn-HA films were characterized with X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS).

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Effect of the flow rate of nitrogen sputter gas on the properties of thin zirconium oxynitride films

  • 박주연;조준모;강용철
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2009년도 제38회 동계학술대회 초록집
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    • pp.384-384
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    • 2010
  • Zirconium oxynitride films were obtained by r.f. reactive magnetron sputtering of a zirconium target with nitrogen flow rate ranging from 0 to 60 sccm. The phases present in the films were determined by X-ray diffraction (XRD). Measurements of the oxidation state $ZrON_x$ films were investigated by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Thickness of these samples was estimated by spectroscopic ellipsometry (SE) and scanning electron microscopy (SEM). We found that the surface morphology of $ZrON_x$ films measured by atomic force microscopy (AFM) was also depended on the nitrogen gas flow.

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고밀도 플라즈마에 의한 BST 박막의 damage에 관한 연구 (Damages of etched BST fins by high density plasmas)

  • 최성기;김창일;장의구;서용진;이우선
    • 한국항해항만학회:학술대회논문집
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    • 한국항해항만학회 2000년도 추계학술대회논문집
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    • pp.45-48
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    • 2000
  • High dielectric (Ba,Sr)TiO$_3$thin films were etched in an inductively coupled plasma (ICP) as a function of C1$_2$/Ar gas mixing ratio. Under Cl$_2$(20)/Ar(80), the maximum etch rate of the BST films was 400$\AA$/min and selectivities of BST to Pt and PR were obtained 0.4 and 0.2, respectively. We investigated the etched surface of BST by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and x-ray diffraction (XRD). From the result of XPS analysis, we found that residues of Ba-Cl and Ti-Cl bonds remained on the surface of the etched BST for high boiling point. The surface roughness decreased as Cl$_2$increases in C1$_2$/Ar plasma because of non-volatile etching products. This changed the nature of the crystallinity of BST. From the result of XRD analysis, the crystallinity of etched BST film maintained as similar to as-deposited BST under Ar only and Cl$_2$(20)/Ar(80). However, (100) orientation intensity of etched BST film abruptly decreased at Cl$_2$only plasma. It was caused that Cl compounds were redeposited on the etched BST surface and damaged to crystallinity of BST film during the etch process.

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Selective Oxidation of Hydrogen Sulfide to Elemental Sulfur with Fe/MgO Catalysts in a Slurry Reactor

  • Lee, Eun-Ku;Jung, Kwang-Deog;Joo, Oh-Shim;Shul, Yong-Gun
    • Bulletin of the Korean Chemical Society
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    • 제26권2호
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    • pp.281-284
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    • 2005
  • The Fe/MgO catalysts with different Fe loadings (1, 4, 6, 15 and 30 wt% Fe) were prepared by a wet impregnation with iron nitrate as precursor. All of the catalysts were characterized by BET surface analyzer, X-ray diffraction (XRD), temperature-programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS). The maximum removal capacity of $H_2S$ was obtained with 15 wt% Fe/MgO catalyst which had the highest BET surface area among the measured catalysts. XRD of Fe/MgO catalysts showed that well dispersed Fe particles could be present on Fe/MgO with Fe loadings below 15 wt%. The crystallites of bulk $\alpha$-$Fe_2O_3$ became evident on 30 wt% Fe/MgO, which were confirmed by XRD. TPR profiles showed that the reducibility of Fe/MgO was strongly related to the loaded amounts of Fe on MgO support. Therefore, the highest removal efficiency of $H_2S$ in wet oxidation could be ascribed to a good dispersion and high reducibility of Fe/MgO catalyst. XPS studies indicated that the $H_2S$ oxidation with Fe/MgO could proceed via the redox mechanism ($Fe^{3+}\;{\leftrightarrow}\;Fe^{2+}$).

고밀도 플라즈마에 의한 BST 박막의 damage에 관한 연구 (Damages of etched BST films by high density plasmas)

  • 최성기;김창일;장의구;서용진;이우선
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 추계학술대회 논문집
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    • pp.45-48
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    • 2000
  • High dielectric (Ba,Sr)TiO$_3$ thin films were etched in an inductively coupled plasma (ICP) as a function of C1$_2$/Ar gas mixing ratio. Under Cl$_2$(20)/Ar(80), the maximum etch rate of the BST films was 400$\AA$/min and selectivities of BST to Pt and PR were obtained 0.4 and 0.2, respectively. We investigated the etched surface of BST by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and x-ray diffraction (XRD). From the result of XPS analysis, we found that residues of Ba-Cl and Ti-Cl bonds remained on the surface of the etched BST for high boiling point. The surface roughness decreased as Cl$_2$ increases in Cl$_2$/Ar plasma because of non-volatile etching products. This changed the nature of the crystallinity of BST. From the result of XRD analysis, the crystalliility of etched BST film maintained as similar to as-deposited BST under Ar only and Cl$_2$(20)/Ar(80). However, (100) orientation intensity of etched BST film abruptly decreased at Cl$_2$ only plasma. It was caused that Cl compounds were redeposited on the etched BST surface and damaged to crystallinity of BST film during the etch process.

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MWCNT와 여러가지 티탄알콕사이드 전구체를 사용하여 CNT/TiO2 복합체의 제조와 광촉매분해 (Preparation and photocatalytic degradation of CNT/TiO2 composites using MWCNT and various titanium alkoxide precursors)

  • 진명량;장봉군;오원춘
    • 분석과학
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    • 제21권6호
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    • pp.553-561
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    • 2008
  • MWCNT 와 여러 가지 티탄 알콕사이드 전구체를 사용하여 $CNT/TiO_2$ 복합제를 제조하였다. 이들 복합체들은 SEM, FE-SEM, XRD, EDX 및 UV-vis 분광기를 사용하여 종합적으로 분석하였다. UV 조사하에서 MB모델 수용액의 변이에 대한결과로부터 제조된 물질에 대한 광활성을 시험하였다. 마지막으로 MB 제거 실험의 결과에 따르면, 시료 CTOS의 경우 시료 CTIP 및 CTPP의 경우보다 우수한 MB제거 효과를 나타내었다.

Superconducting properties and microstructure of electron beam irradiated MgB2 superconductors

  • Kim, C.J.;Lee, Y.J.;Cho, I.H.;Jun, B.H.
    • 한국초전도ㆍ저온공학회논문지
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    • 제24권1호
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    • pp.18-22
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    • 2022
  • The effect of electron beam (EB) irradiation on superconducting properties and microstructures of MgB2 bulk superconductors were investigated. At E-beam doses of 1×1016 e/cm2 and 1×1017 e/cm2, the effect of irradiation on a superconducting transition temperature (Tc) of MgB2 was weak. As a dose increases to 5×1017 e/cm2, Tc decreases by 0.5 K. The critical current density (Jc) measured at 4.2 K and 20 K, and 0 T - 5 T increases slightly as exposure time increases. X-ray diffraction for the irradiation surface of MgB2 shows that the diffraction intensity of (hkl) peaks decreases proportionally as the exposure time increases. This indicates that the crystallinity of MgB2 was degraded by irradiation. TEM investigation for the irradiated sample showed distorted lattice structure, which is consistent with the XRD results. The Jc increase and Tc reduction of MgB2 by irradiation are believed to be caused by the lattice distortion.

An investigation of the nuclear shielding effectiveness of some transparent glasses manufactured from natural quartz doped lead cations

  • Kassem, Said M.;Ahmed, G.S.M.;Rashad, A.M.;Salem, S.M.;Ebraheem, S.;Mostafa, A.G.
    • Nuclear Engineering and Technology
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    • 제53권6호
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    • pp.2025-2037
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    • 2021
  • The influence of lead cations on natural quartz (QZ) from Egypt as a glass shielding material for the composition with nominal formula (10Na2O - (90 - x) QZ - xPbO (where x = 30, 35, 40, 45 and 50 mol %)) was examined. The studied samples are synthesized via the melt quenching method at 1050 ℃. The X-ray diffraction XRD patterns were confirmed the glass nature for studied samples. Moreover, the optical properties, and the transparency for all compositions were examined by UV-Vis spectroscopy. Also, the major elemental composition of the natural quartz were estimated via the X-ray fluorescence (XRF) technique. Further, the density and molar volume were determined. Furthermore, the nuclear shielding parameters such as, mass attenuation coefficient, effective atomic number, electronic density, the total atomic, and electronic cross sections as well as the mean free path, and the half value layer with different gamma ray energies (81 keV-1407 keV) were calculated. Besides, the results showed that the shielding behavior towards the gamma ray radiation for all glass samples was increased as the increment in PbO concentration in the glass system.

The Preparation of Alumina Particles Wrapped in Few-layer Graphene Sheets and Their Application to Dye-sensitized Solar Cells

  • Ahn, Kwang-Soon;Seo, Sang-Won;Park, Jeong-Hyun;Min, Bong-Ki;Jung, Woo-Sik
    • Bulletin of the Korean Chemical Society
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    • 제32권5호
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    • pp.1579-1582
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    • 2011
  • Alumina particles wrapped in few-layer graphene sheets were prepared by calcining aluminum nitride powders under a mixed gas flow of carbon monoxide and argon. The graphene sheets were characterized by powder X-ray diffraction (XRD), Raman spectroscopy, electron energy loss spectroscopy, and high-resolution transmission electron microscopy. The few-layer graphene sheets, which wrapped around the alumina particles, did not exhibit any diffraction peaks in the XRD patterns but did show three characteristic bands (D, G, and 2D bands) in the Raman spectra. The dye-sensitized solar cell (DSSC) with the alumina particles wrapped in few-layer graphene sheets exhibited significantly improved overall energy-conversion efficiency, compared to conventional DSSC, due to longer electron lifetime.

DEGRADATION OF Zn$_3$$N_2$ FILMS PREPARED BY REACTIVE RF MAGNETRON SPUTTERING

  • Futsuhara, Masanobu;Yoshioka, Katsuaki;Takai, Osamu
    • 한국표면공학회지
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    • 제29권5호
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    • pp.563-569
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    • 1996
  • Degradation of $Zn_3N_2$ films is studied by using several analytical techniques. Polycrystalline $Zn_3N_2$ films prepared by reactie rf magnetron sputtering are kept in the air. Electrical and optical properties are measured by using van der Pauw technique and double-beam spectrometry. Structure and chemical bonding states are studied by X-ray diffraction(XRD), Fourier transfer infrared ray spectroscopy(FT-IR) and X-ray photoelectron specroscopy (XPS). Significant differences are observed in optical properties between the degraded film and the ZnO film. XRD analysis reveals that the degraded film contains very small ZnO grains because very weak and broad ZnO peaks are observed. XPS and FT-IR measurements reveal the formation of $Zn(OH)_2$ in the degraded film. The existence of N-H bonds in degraded films is exhibited from the N 1s spectra. $Zn_3N_2$ change into the mixture of ZnO, $Zn(OH)_2$ and an ammonium salt.

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