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Wyszukujesz frazę "Ko, S.-Y." wg kryterium: Autor


Wyświetlanie 1-8 z 8
Tytuł:
Effect of Additives on the Densification Processes and Properties of Silica-Based CMCs
Autorzy:
Ko, S.-Y.
Yong, S.-M.
Lee, S. J.
Cheong, D.-I.
Baek, S.
Powiązania:
https://bibliotekanauki.pl/articles/355134.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ceramic matrix composite
CMC
silica
densification
mechanical properties
Opis:
The effect of additives on the densification behavior and mechanical properties of pure and additive (Zr, B and Mg)-added silica ceramics were investigated for their application to the matrix phase of a silica fiber reinforced silica (SiO2 /SiO2f ) composite. The additives affected the rate of densification and crystallization (or transformation) of the amorphous silica. Among the compositions, pure silica ceramics sintered at 900°C for 1h showed the maximum flexural strength. Based on the results, SiO2 /SiO2f was fabricated by a repeated vacuum-assisted infiltration method followed by the heat treatment at 900°C for 1h. The relative density of the composite was 78.2% with a flexural strength of 22.4 MPa. Fractography revealed that the composite was damaged by strong bonding at the fiber/matrix interface and the fracture of fiber.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1485-1488
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the Calcination Temperature on the Optical and Mechanical Properties of Y2O3-MgO Nanocomposite
Autorzy:
Yong, S.-M.
Choi, D. H.
Lee, K.
Ko, S.-Y.
Cheong, D.-I.
Powiązania:
https://bibliotekanauki.pl/articles/351252.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
infrared transparent ceramics
Y2O3-MgO nanocomposites
sol-gel combustion synthesis
calcination
spark plasma sintering
Opis:
Y2O3-MgO nanocomposites are one of the most promising materials for hypersonic infrared windows and domes due to their excellent optical transmittance and mechanical properties. In this study, influence of the calcination temperature of Y2O3-MgO nanopowders on the microstructure, IR transmittance, and hardness of Y2O3-MgO nanocomposites was investigated. It was found that the calcination temperature is related to the presence of residual intergranular pores and grain size after spark plasma sintering. The nanopowders calcined at 1000°C exhibits the highest infrared transmittance (82.3% at 5.3 μm) and hardness (9.99 GPa). These findings indicated that initial particle size and distribution of the nanopowders are important factors determining the optical and mechanical performances of Y2O3-MgO nanocomposites.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1481-1484
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interface Engineering in Heteroepitaxy
Autorzy:
Hong, S. K.
Chen, Y.
Ko, H. J.
Yao, T.
Powiązania:
https://bibliotekanauki.pl/articles/2035571.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.35.-p
68.35.Dv
81.15.-z
81.15.Hi
81.10.Aj
Opis:
We report the importance of interface engineering in heteroepitaxy with examples of plasma-assisted molecular beam epitaxial ZnO growths on (0001) sapphire substrates and on (0001) GaN/sapphire templates, whose interfaces are engineered to improve and to control properties of ZnO films. The growth of rocksalt structure MgO buffer on Al$\text{}_{2}$O$\text{}_{3}$ (0001) is developed for ZnO epitaxy. By employing the MgO buffer layer, the formation of 30$\text{}^{o}$ rotated mixed domains is prohibited and two-dimensional layer-by-layer growth of ZnO on sapphire substrate is achieved. High-resolution X-ray diffraction reveals the superior improvement in a crystal quality of ZnO films with an MgO buffer. Polarity of wurtzite structure ZnO films on Ga-polar GaN/sapphire templates is controlled by changing interface structures. By forming a single crystalline, monoclinic Ga$\text{}_{2}$O$\text{}_{3}$ interfacial layer between GaN and ZnO through O-plasma pre-exposure on the Ga-polar GaN surface, O-polar ZnO films are grown. By forming the ZnO/GaN heterointerface without an interfacial layer through the Zn pre-exposure on the Ga-polar GaN surface, Zn-polar ZnO films are grown.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 541-554
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Isotopic water separation using AGMD and VEMD
Autorzy:
Kim, J.
Park, S.
Kim, T.-S.
Jeong, D.-Y.
Ko, K.-H.
Powiązania:
https://bibliotekanauki.pl/articles/147314.pdf
Data publikacji:
2004
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
AGMD
VEMD
oxygen isotopes
PET
FDG
Opis:
The 18O isotopic water permeation and separation characteristics of a hydrophobic PTFE membrane using Air Gap Membrane Distillation (AGMD) and Vacuum Enhanced Membrane Distillation (VEMD) were investigated. Permeation fluxes were measured by weighing the collected membrane-permeated water vapor. 18O/16O of each water sample was analyzed by the Tunable Diode Laser Absorption Spectroscopy (TDLAS). We observed the effects of the air filled membrane pores and the temperature gradient applied to the membrane surfaces on the vapor permeation flux and the oxygen isotope separation for the first time. For both AGMD and VEMD, the permeation flux and the degree of 18O separation increased as the membrane interfacial temperature gradient increased. Even though, oxygen isotope separation and the permeation flux for VEMD is slightly higher than AGMD, the latter may be more efficient from the system's operational point of view.
Źródło:
Nukleonika; 2004, 49, 4; 137-142
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The High Temperature Oxidation Stability of STS434L/Silicon Oxide Compacts
Autorzy:
Park, J. W.
Ko, B. H.
Jung, W. Y.
Park, D. K.
Ahn, I. S.
Powiązania:
https://bibliotekanauki.pl/articles/352481.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high-temperature oxidation stability
metallic oxide
densification
Opis:
In order to improve the high-temperature oxidation stability, a study of 434L sintered stainless steel was focused on the effect of addition of metallic oxides to form stable oxide film on the inner particle surface. In this paper, oxidation behavior of 434L compacted parts in accordance with the addition of metallic oxides were discussed with high temperature oxidative reaction, and sintering behavior analysis under 950°C. Oxidation weight gains of 434 L have increased as a form of parabolic laws. The hightemperature oxidation resistance was improved by the mixed addition of amorphous SiO2 and silica up to 2wt.%. The oxidation rate was decreased and kept constant after 60 hours. It was caused by the restraint succeeding oxidation due to the stable oxide formation of Cr2SiO4 phases on the particle surface to prevent densification and inhibition the external diffusion of Cr. High-temperature stability was confirmed by the electrical resistivity maintains the constant value of 1.3×10-2 Ω ·cm when the silica added less than 2w/o to 1w/o A-SiO2 added 434L.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 1; 307-313
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neutron emission parameters from the collapse of the condensed Z-pinch
Autorzy:
Anan'ev, S. S.
Bakshaev, Y. L.
Bryzgunov, V. A.
Chernenko, A. S.
Dan'ko, S. A.
Kazakov, E. D.
Klír, D.
Korolev, V. D.
Smirnova, E. A.
Ustroev, G. I.
Vikhrev, V. V.
Powiązania:
https://bibliotekanauki.pl/articles/146662.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
neutrons
energy distribution
fast Z-pinch
Opis:
The parameters of neutron emission from the neck of the condensed Z-pinch, were measured at an S-300 installation (2 MA, 100 ns). Profiled loads with central parts made from microporous deuterated polyethylene (with a density of 100 mg/cm3) were used in the experiments. Neutron emission parameters were measured by the time-of-flight (TOF) method. Neutrons were registered using four flight bases with 10 scintillation detectors which were placed at two axial and two radial directions. It was found that the mean neutron energy, determined by the TOF method, turned out to be anisotropic. The average energy of neutrons emitted along the axis towards the cathode, was shifted to higher energy (2.6-2.8 MeV) and the average energy of neutrons emitted towards the anode, was shifted to lower energy (2.1-2.3 MeV) compared to the d-d reaction neutron energy 2.45 MeV. The average energy of neutrons, emitted in two opposite radial directions, was close to 2.45 MeV. The half-width of the energy distributions reconstructed for all directions was 400-500 keV. The analysis of the experimental results demonstrated that the found phenomena could be explained by a slowly decaying high energy tail in the energy distribution of colliding deuterons. The maximal neutron yield was of 6 x 109.
Źródło:
Nukleonika; 2012, 57, 3; 333-336
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stabilizing of Z-pinch and Plasma Focus discharges due to thick wires
Autorzy:
Kubeš, P.
Kravárik, J.
Paduch, M.
Tomaszewski, K.
Scholz, M.
Karpinski, L.
Szydlowski, A.
Bakshaev, Y.
Blinov, P.
Chernenko, A. S.
Gordeev, E. M.
Dan’ko, S. A.
Korolev, V. D.
Shashkov, A.
Tumanov, V. I.
Romanova, V.
Klír, D.
Powiązania:
https://bibliotekanauki.pl/articles/146991.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma focus
X-ray source
XUV spectroscopy
Z-pinch
Opis:
This paper presents the results of the diagnostics observing the impact of the plasma sheath imploded in megaamper Z-pinch or plasma focus devices onto the Al or C wires of 30-300 mi m in diameter fixed in the center axis. The discharges were operated with a maximum current of 1.5-3 MA at two devices, PF 1000 at IPFLM in Warsaw, and Stand 300 at RRC Kurchatov Institute in Moscow. At the plasma impact the 10-50 ns XUV pulse was emitted in K-shell lines from the ring or helical-like forms on the surface of the wire corona. The scenario of the production of the non-equilibrium intensities of the C and Al H-like and He-like lines is discussed considering fast transformation of magnetic field, electron beams acceleration, total ionization of the ions and fast recombination in dense and magnetized wire corona.
Źródło:
Nukleonika; 2001, 46, 1; 5-7
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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