Arama Sonuçları

Listeleniyor 1 - 3 / 3
  • Yayın
    Electrochromic switching of WO3 nanostructures and thin films
    (Springer-Verlag, 2006-04) Karakurt, İsmail; Boneberg, Johannes; Leiderer, Paul
    We present transmission measurements through tungsten tri-oxide nanostructures and thin films prepared by sol-gel process on micro-contact printed substrates. Identical electrochromic switching times are found for both the nanostructures and the bulk films with equal thicknesses upon intercalation of H+ ions. We attribute the large change in the transmission through nanostructures at 632 nm, which can not be solely explained by absorption, to diffraction effects.
  • Yayın
    Transmission increase upon switching of VO2 thin films on microstructured surfaces
    (American Institute of Physics, 2007-08-27) Karakurt, İsmail; Boneberg, Johannes; Leiderer, Paul; Lopez, Rene; Halabica, Andrej; Haglund, Richard F.
    The authors compare transmission measurements of near-infrared light through VO2 thin films on smooth substrates and on ordered arrays of silica microspheres. When the samples are heated above the critical temperature for the semiconductor-metallic phase transition, smooth thin films show reduced transmission independent of thickness; however, the VO2 film deposited on the microspheres may show either reduced or enhanced transmission, depending on VO2 film thickness. They show that this at a first glance, unexpected behavior is directly related to the change of scattering efficiency upon the phase transition. This suggests that optical transmission through thin-film microstructures could be tuned by an appropriate combination of microsphere ordering and VO2 film thickness.
  • Yayın
    Effect of magnesium and osteoblast cell presence on hydroxyapatite formation on (Ti,Mg)N thin film coatings
    (Springer, 2016-07-19) Önder, Sakip; Çalıkoğlu Koyuncu, Ayşe Ceren Eren; Köse, Gamze Torun; Kazmanlı, Kürşat Muhammet; Kök, Fatma Neşe; Ürgen, Mustafa
    TiN and (Ti,Mg)N thin film coatings were deposited on Ti substrates by an arc-physical vapor deposition technique. The effect of cell presence on hydroxyapatite (HA) formation was investigated using surfaces with four different Mg contents (0, 8.1, 11.31, and 28.49 at.%). Accelerated corrosion above 10 at.% Mg had a negative effect on the performance in terms of both cell proliferation and mineralization. In the absence of cells, Mg-free TiN coatings and low-Mg (8.1 at.%)-doped (Ti,Mg)N surfaces led to an early HA deposition (after 7 days and 14 days, respectively) in cell culture medium (DMEM), but the crystallinity was low. More crystalline HA structures were obtained in the presence of the cells. HA deposits with an ideal Ca/P ratio were obtained at least a week earlier, at day 14, in TiN and low-Mg (8.1 at.%)-doped (Ti,Mg)N compared with that of high-Mg-containing surfaces (>10 at.%). A thicker mineralized matrix was formed on low-Mg (8.1 at.%)-doped (Ti,Mg)N relative to that of the TiN sample. Low-Mg doping (<10 at.%) into TiN coatings resulted in better cell proliferation and thicker mineralized matrix formation, so it could be a promising alternative for hard tissue applications.