Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

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

Browse

Filters

20253

Settings

Publisher: search.filters.publisher.Pleiades Publishing Ltd

Search Results

Now showing 1 - 3 of 3
  • Article
    Quantum Calculus of Fibonacci Divisors and Fermion-Boson Entanglement for Infinite Hierarchy of N=2 Supersymmetric Golden Oscillators
    (Pleiades Publishing Ltd, 2025) Pashaev, O. K.
    The quantum calculus with two bases, represented by powers of the golden and silver ratios, relates the Fibonacci divisor derivative with Binet formula for the Fibonacci divisor number operator, acting in the Fock space of quantum states. It provides a tool to study the hierarchy of golden oscillators with energy spectrum in the form of Fibonacci divisor numbers. We generalize this model to the supersymmetric number operator and corresponding Binet formula for the supersymmetric Fibonacci divisor number operator. The operator determines Hamiltonian of the hierarchy of supersymmetric golden oscillators, acting in fermion-boson Hilbert space and belonging to N = 2 supersymmetric algebra. The eigenstates of the super Fibonacci divisor number operator are double degenerate and can be characterized by a point on the super-Bloch sphere. By introducing the supersymmetric Fibonacci divisor annihilation operator, we construct the hierarchy of supersymmetric coherent states as eigenstates of this operator. The entanglement of fermions with bosons in these states is calculated by the concurrence, represented as the Gram determinant and expressed in terms of the hierarchy of golden exponential functions. We show that the reference states and the corresponding von Neumann entropy measuring the fermion-boson entanglement are characterized completely by powers of the golden ratio. We give a geometrical classification of entangled states by the Frobenius ball and interpret the concurrence as the double area of a parallelogram in a Hilbert space.
  • Article
    The Temperature Dependence of Elastic Constants and Zener Anisotropy in Single Crystal KTaO3 Below Room Temperature
    (Pleiades Publishing Ltd, 2025) Li, C. H.; Ding, X. D.; Carpenter, M. A.; Aktas, O.
    We present the first experimental report of the complete elastic tensor of incipient ferroelectric KTaO3 between 9.6 and 307 K, using resonant ultrasound spectroscopy (RUS). The elastic constants C-11 and C-44, as well as the bulk and shear moduli increase roughly linearly upon cooling. Deviations from such dependence are a result of impurities. Zener anisotropy factor is 0.697 at room temperature and decreases to 0.627 at 9.6 K, indicating increasing elastic anisotropy. The temperature dependence of C-12 is anomalous with no stiffening on cooling, which could be a result of different defect species influencing C-12 but not the other constants, possibly due to defect anisotropy. The values of elastic constants and anisotropy are compared at room temperature and below 10 K with the literature reporting experimental results and density functional theory calculations.
  • Article
    A Comparative Study on Experimental and FEA-Based Simulation of Dry Sliding Wear Behavior of Boronized AISI 304 Stainless Steel at Elevated Temperatures
    (Pleiades Publishing Ltd, 2025) Gok, Mustafa Sabri; Kucuk, Yilmaz; Khosravi, Farshid; Gunen, Ali; Karakas, Mustafa Serdar; Guden, Mustafa
    In this study, the influence of boronizing on the high-temperature wear behavior of AISI 304 was examined experimentally and with FEA simulation. Boronizing, conducted at 950 degrees C for 3 h using the powder-pack boronizing technique, showed an approximately 7-fold increase in hardness compared to untreated sample. Boride layer characterization was performed using XRD, SEM, and EDS line analyses. Wear tests were performed at ambient temperatures of 25, 250, and 500 degrees C. While the wear rates of the untreated sample increased dramatically with increasing temperature, those of the boronized samples were significantly limited. FEA simulation using the Johnson-Cook fracture model demonstrated a high degree of consistency with the experimental wear profiles and this alignment enables reliable wear predictions. The oxide layer formation was observed on the worn surface of boronized samples during the tests at elevated temperatures, resulting in less plastic deformation.