Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Department: search.filters.department.İzmir Institute of Technology. PhysicsPublisher: search.filters.publisher.TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu

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  • Article
    Citation - WoS: 1
    Citation - Scopus: 2
    Reactive Wetting of Metallic/Ceramic (al/Α-al2 O3 ) Systems: a Parallel Molecular Dynamics Simulation Study
    (TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2020) Aral, Gürcan; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of Technology
    The reactive wetting process of a flat solid alumina (?-Al2 O3) ceramic surface by metallic aluminum (Al) nanodroplets with different shapes (spherical, cylindrical, and layer) is studied using parallel molecular dynamics (MD) simulations based on a variable charge MD method, with focuses on heat transfer, mass transfer, and the structure of the reactive region at the Al/?-Al2 O3 interface. We find that the diffusion of oxygen (O) atoms from the substrate into the droplet leads to the formation of a continuous layer of reaction product at the interface. The diffusion length of oxygen atoms into the spherical Al droplet is found to be ~7.3 Å, and the number density of O atoms at the ~5 top layers of the substrate decreases substantially. As a result, the structural correlations near the reactive region differ considerably from those in the solid substrate. Heat generated by the exothermic reactions in the reactive region is transferred to both the substrate and the droplet. The heat transfer is found to be sensitive to droplet shape.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Local Vibrational Modes of Natural Isotopes of Substitutional Oxygen in Cdte
    (TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2020) Tarhan, Enver; Tarhan, Enver; Ramdas, Anant K.; Tarhan, Enver; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of Technology
    We investigated the localized vibrational modes (LVM) of natural oxygen containing ${}^{16}O,\;{}^{17}O$ and ${}^{18}O$ isotopes at a substitutional tellurium site in cadmium telluride using infrared absorption spectroscopy at cryogenic temperatures. The main absorption peak observed at 350 cm ?1 was formerly attributed to a fundamental LVM mode (?0) of oxygen at a tellurium site. The relatively weak absorption peaks observed at 331 $cm^{-1}$ and 340 $cm^{-1}$ are assigned as the same $\nu_0$ mode of the ${}^{17}O$ and ${}^{18}O$ isotopes, respectively, based on their relative intensities and spectral positions. The spectral positions were confirmed with theoretical calculations using a linear chain model where the peak position at 350$cm^{-1}$ was taken as the reference for the ${}^{16}O$ isotope. From a least square analysis of the observed peak positions we were able to calculate the force constants from perturbation theory. A Lorentzian line shape analysis of each $\nu_0$ absorption peak, considering the effects of isotopic mass and natural abundance variations of the host Cd atoms, was also carried out to further confirm their assignments. Reasonably good line shape fittings were obtained for $\nu_0$ modes of all isotopes of oxygen.