Now showing items 1-20 of 20

    • Ab initio temperature dependent studies of the homoepitaxial growth on Si(0 0 1) surface 

      Dağ, S.; Çıracı, Salim; Kılıç, Ç.; Fong, C. Y. (2001)
      We performed ab initio zero temperature and finite temperature molecular dynamics calculations to investigate the homoepitaxial growth on the Si(0 0 1) surface. How do the deposited atoms (adatoms) form addimers and how ...
    • Dependence of the photoluminescence of Tl2InGaS4 layered crystal on temperature and excitation intensity 

      Gasanly, N. M.; Serpengüzel, A.; Gürlü, O.; Aydınlı, A.; Yılmaz, I. (Pergamon Press, 1998)
      The emission band spectra of Tl2InGaS4 layered crystals were investigated in the 10-120 K temperature range and in the 540-860 nm wavelength range using photoluminescence (PL). The peak energy position of the emission band ...
    • Electrical conduction properties of Si δ-doped GaAs grown by MBE 

      Yildiz, A.; Lisesivdin, S.B.; Altuntas H.; Kasap, M.; Ozcelik, S. (2009)
      The temperature dependent Hall effect and resistivity measurements of Si δ-doped GaAs are performed in a temperature range of 25-300 K. The temperature dependence of carrier concentration shows a characteristic minimum at ...
    • Finite temperature studies of Te adsorption on Si(0 0 1) 

      Sen, P.; Çıracı, Salim; Batra, I. P.; Grein, C. H.; Sivananthan, S. (Elsevier, 2002)
      We perform first principles density functional calculations to investigate the adsorption of Te on the Si(0 0 1) surface from low coverage up to a monolayer coverage. At low coverage, a Te atom is adsorbed on top of the ...
    • Free expansion of two-dimensional condensates with a vortex 

      Hoşten, O.; Vignolo, P.; Minguzzi, A.; Tanatar, Bilal; Tosi, M. P. (Institute of Physics Publishing, 2003)
      We study the free expansion of a pancake-shaped Bose-condensed gas, which is initially trapped under harmonic confinement and containing a vortex at its centre. In the case of a radial expansion holding the axial confinement ...
    • Hydrogen storage capacity of titanium met-cars 

      Akman, N.; Durgun, E.; Yildirim, T.; Çıracı, Salim (IOP Publishing Ltd., 2006)
      The adsorption of hydrogen molecules on the titanium metallocarbohedryne (met-car) cluster has been investigated by using the first-principles plane wave method. We have found that, while a single Ti atom at the corner can ...
    • A new method of probing the phonon mechanism in superconductors, including MgB2 

      Park, M.-A.; Savran, K.; Kim, Y.-J. (2001)
      Weak localization has a strong influence on both the normal and superconducting properties of metals. In particular, since weak localization leads to the decoupling of electrons and phonons, the temperature dependence of ...
    • The off-resonant aspects of decoherence and a critique of the two-level approximation 

      Savran, K.; Hakioǧlu T.; Mese, E.; Sevinçli, H. (IOP Institute of Physics, 2006)
      Conditions in favour of a realistic multilevelled description of a decohering quantum system are examined. In this regard the first crucial observation is that the thermal effects, contrary to the conventional belief, play ...
    • Plasmons and the drag effect in a strong magnetic field 

      Manolescu, A.; Tanatar, Bilal (Elsevier B.V., 2002)
      We study the effect of magnetoplasmons on the drag resistance in a strong magnetic field, at finite temperatures. The typical magnetic field is about 1 T, and the temperature is up to 10 K. The Landau levels are broadened ...
    • A radiotracer study of the adsorption behavior of aqueous Ba2+ ions on nanoparticles of zero-valent iron 

      Çelebi O.; Üzüm, C.; Shahwan, T.; Erten H.N. (2007)
      Recently, iron nanoparticles are increasingly being tested as adsorbents for various types of organic and inorganic pollutants. In this study, nanoparticles of zero-valent iron (NZVI) synthesized under atmospheric conditions ...
    • Routes of formation and composition of NOx complexes adsorbed on palladium-promoted tungstated zirconia 

      Kantcheva, M.; Cayirtepe, I. (2006)
      Surface species obtained during the adsorption of NO and NO/O2 coadsorption at room temperature on Pd-free (WZ) and Pd-promoted tungstated zirconia (Pd/WZ) are identified by means of in situ FT-IR spectroscopy. The WZ and ...
    • Sorption of Cs+ and Ba2+ on magnesite 

      Shahwan, Talal; Süzer, Şefik; Erten, Hasan N. (Cambridge University Press, 1998)
      Sorption behavior of Cs and Ba ions on magnesite was studied using the radiotracer method complemented by X-ray photoelectron spectroscopy. Cs and Ba were used as radiotracers. The sorption of Cs is seen to be temperature ...
    • Sorption studies of Cs+ and Ba2+ cations on magnesite 

      Shahwan, T.; Suzer, S.; Erten, H. N. (Elsevier, 1998-05-11)
      The adsorption behavior of Cs+ and Ba2+ cations on magnesite has been studied as a function of time, cation concentration and temperature, utilizing both the radiotracer method and X-ray photoelectron spectroscopy (XPS). ...
    • Temperature and magnetic field dependence of superconductivity in nanoscopic metallic grains 

      Bozat Ö.; Gedik, Z. (Elsevier Science, 2001)
      We study pairing correlations in ultrasmall superconductor in the nanoscopic limit by means of a toy model where electrons are confined in a single, multiply degenerate energy level. We solve the model exactly to investigate ...
    • Temperature dependence of the first-order Raman scattering in GaS layered crystals 

      Gasanly, N. M.; Aydınlı, A.; Özkan, H.; Kocabaş, C. (Pergamon Press, 2000)
      The temperature dependence (15-293 K) of the six Raman-active mode frequencies and linewidths in gallium sulfide has been measured in the frequency range from 15 to 380 cm-1. We observed softening and broadening of the ...
    • Temperature dependence of the Raman-active phonon frequencies in indium sulfide 

      Gasanly, N. M.; Özkan, H.; Aydinli, A.; Yilmaz, I. (Pergamon Press, 1999)
      The temperature dependence of the Raman-active mode frequencies in indium sulfide was measured in the range from 10 to 300 K. The analysis of the temperature dependence of the A g intralayer optical modes show that Raman ...
    • Texturing of titanium (Ti6Al4V) medical implant surfaces with MHz-repetition-rate femtosecond and picosecond Yb-doped fiber lasers 

      Erdoǧan, M.; Öktem, B.; Kalaycioǧlu H.; Yavaş, S.; Mukhopadhyay P.K.; Eken, K.; Özgören, K.; Aykaç, Y.; Tazebay, U.H.; Ilday F.O. (Optical Society of American (OSA), 2011)
      We propose and demonstrate the use of short pulsed fiber lasers in surface texturing using MHz-repetition-rate, microjoule- and sub-microjoule-energy pulses. Texturing of titanium-based (Ti6Al4V) dental implant surfaces ...
    • Thermally stimulated current observation of trapping centers in undoped GaSe layered single crystals 

      Gasanly, N. M.; Aydınlı, A.; Salihoglu, Ö. (Wiley, 2001)
      Undoped p-GaSe layered single crystals were grown using Bridgman technique. Thermally stimulated current measurements in the temperature range of 10-300 K were performed at a heating rate of 0.18 K/s. The analysis of the ...
    • Thermally stimulated currents in n-InS single crystals 

      Gasanly, N. M.; Aydinli, A.; Yuksek, N. S. (Elsevier Science, 2003)
      Thermally stimulated current measurements are carried out on as-grown n-InS single crystals in the temperature range of 10-125 K. Experimental evidence is found for four trapping centers present in InS. They are located ...
    • Trapping centers in undoped GaS layered single crystals 

      Gasanly, N. M.; Aydinli, A.; Yüksek, N. S.; Salihoglu, Ö. (Springer, 2003)
      Nominally undoped p-GaS layered single crystals were grown using the Bridgman technique. Thermally stimulated current measurements in the temperature range 10-300 K were performed at a heating rate of 0.10 K/s. The analysis ...