Browsing by Subject "Ionization"

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    High fluence effects on ion implantation stopping and range
    (2005) Selvi S.; Tek Z.; Öztarhan A.; Akbaş N.; Brown I.G.
    We have developed a code STOPPO which can be used to modify the more-widely used ion implantation codes to more accurately predict the mean nuclear and electronic stopping power, preferential sputtering and range of heavy ions in monatomic target materials. In our simulations an effective atomic number and effective atomic mass are introduced into conveniently available analytical stopping cross-sections and a better fitting function for preferential sputtering yield is carefully evaluated for each ion implantation. The accuracy of the code confirmed experimentally by comparison with measured Rutherford backscattering spectrometry (RBS) concentration profiles for 130 keV Zr ions implanted into Be to fluences of 1 × 1017, 2 × 10 17 and 4 × 1017 ions/cm2. We find a steady increase in the mean nuclear and electronic stopping powers of the target; the increase in nuclear stopping power is much greater than the increase in electronic stopping power. © 2004 Elsevier B.V. All rights reserved.
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    Synthesis and vibrational spectroscopic studies of isonicotinamide metal(II) halide complexes
    (2006) Ataç A.; Yurdakul S.; Ide S.
    Fourier transform infrared spectra (4000-200 cm-1) are reported for the metal (II) halide isonicotinamide complexes of the following stoichiometries: M(iso)2X2 [MNi, Cu, Hg; XCl; iso=isonicotinamide], M(iso)2X2 [MNi, Cu; XBr], and Co(iso)2I2. Vibrational assignments are given for all the observed bands. The Raman spectra (4000-100 cm-1) are reported for the three of these complexes. Also, the ESR spectra of these complexes are given. For a given series of isomorphous complexes the sum of the difference between the values of the vibrational modes of the free isonicotinamide and complexed ligand was found to increase in the order of the second ionization potentials of metals. The frequency shifts are also found to depend on the halogen. The studied metal halide complexes were characterized by X-ray powder diffraction patterns and FTIR spectra. Certain chemical formulas were determined using elemental analysis results. Finally, the geometry optimization method was used to predict three dimensional molecular geometries of the complexes by using the HYPERCHEM 5.0 the level of the theory molecular mechanic. © 2005 Elsevier B.V. All rights reserved.
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    Ionized and non-ionized radiation effects on coronary stent implantation
    (Elsevier Ltd, 2023) Kilicoglu O.; Sayyed M.I.; Kara U.; Aladag H.İ.; Karadem K.B.
    The purpose of this study is to examine the clinical radiation effects on patients with various stents. Several previous researches focused on the mechanical and physical features of the stents, but there have been few studies that focus on the interaction with radiological and clinical radiation. For stent material analysis, the ANSYS package program was employed. These materials and models are often built in three dimensions for three different types of stents made of three various materials. Estimates of blood pressure and thermal radiation were explored, as were the effects of non-ionizing radiation. Furthermore, the radiation attenuation characteristics of stent samples are investigated. The mass attenuation coefficient values are computed using MATLAB code over a large energy range of 0.015–15 MeV, and the findings are validated using theoretical WinXCom results. To determine the gamma-ray attenuation performances of the studied stent samples, variables such as the mass attenuation coefficient (MAC), half-value layer (HVL), tenth-value layer (TVL), mean free path (MFP), effective atomic number (Zeff), exposure build-up factor (EBF), and energy absorption build-up factor (EABF) are computed. Effective removal cross-sections (ΣR) of stent samples were acquired to determine the capacity of stent samples to stop fast neutrons. Finally, the ability of stent samples to stop charged alpha and proton particles was evaluated utilizing mass stopping power and projected range parameters. The discovery demonstrates that S3 has the best attenuation as well as the best proton, alpha, and gamma radiation attenuation capability. © 2022 Elsevier Ltd