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    Description of Exotic Nuclei with the Interacting Boson Model
    (Amer Inst Physics, 2008) Boyukata, M.; Van Isacker, P.; Uluer, I.
    Even-even nuclei in the A similar to 100 mass region are investigated within the framework of the interacting boson model-1 (IBM-1). The study includes energy spectra and electric quadrupole transition properties of zirconium, molybdenum, ruthenium and palladium isotopes with neutron number N >= 54. A global parametrization of the IBM-1 hamiltonian is found leading to a description of 301 collective levels in 30 nuclei with a root-mean-square deviation from the observed level energies of 119 keV The geometric character of the nuclei can be visualized by plotting the potential energy surface V(beta, gamma) obtained from the IBM-1 hamiltonian in the classical limit. The parametrization established on the basis of known elements is then used to predict properties of the unknown. neutron-rich isotopes Zr-106, (MO)-M-112, Ru-116 and Pd-120.
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    Numerical thickness optimization study of CIGS based solar cells with wxAMPS
    (Elsevier Gmbh, 2016) Yasar, S.; Kahraman, S.; Cetinkaya, S.; Apaydin, S.; Bilican, I.; Uluer, I.
    In this paper, a numerical investigation of the effects of thickness of absorber and buffer layers for a typical CIGS based solar cell was carried out for the first time, employing the wxAMPS software which is a new custom-designed software package for solar cell simulation. We have examined how the output parameters change with absorber and buffer thicknesses and suggested four different cell structures. By using the baseline structure, an optimum band gap value of 1.4 eV was determined for the CIGS absorber layer prior to do thickness study. Optimum absorber thickness value has been determined as 2500 nm from the simulation results. Spectral response of the cell decreased with increasing thickness in blue region. The influence of buffer layer thickness was investigated and it was found that most of the photo-generated carriers are collected by a thinner CdS layer. A significant decrease in current density, open circuit voltage and conversion efficiency occurred with increasing buffer layer thickness. This behavior was attributed to a decrease in the number of collected carriers due to the recombination of electron-hole pairs proceeded from the absorbed photons in the CdS bulk for large thickness. As a result, efficiencies around 27% were obtained through optimization while that of baseline structure was 25%. Our results have shown that the suggested structures both produce higher efficiencies than that of baseline structure and may lead to produce more efficient CIGS-based thin film solar cells. (C) 2016 Elsevier GmbH. All rights reserved.
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    Pre-equilibrium Emission Spectra Calculations of Th-232(n,xn) Using New Evaluated Method
    (Springer, 2011) Tel, E.; Efil, A.; Uluer, I.; Aydin, A.; Sahan, M.
    The knowledge of the thorium (Th-232) cycle potentialities are required for the design of a fusion-fission (hybrid) reactor. Pre-equilibrium nuclear reactions have been used to investigate the effect of initial exciton numbers on the nucleon emission spectra. In this study, the initial exciton numbers for the target nucleus of Th-232 were calculated through a method of offered by Tel et al. and then were used to obtain the effect cross section of the neutron emission spectra. Using this new method, a different way from the literature, the initial exciton numbers calculated with the theoretical neutron and proton densities have been obtained with SKM* on the Th-232(n,xn) reaction at 14.1 and 18.0 MeV incident neutron energies. The results were analyzed by comparing the empirical results in the literature.