Yazar "Gomaa, Hosam M." seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Ni-doped and co-doped borate glasses for energy storage and UV-blocking applications
    (Springer, 2024) Gomaa, Hosam M.; Saudi, H. A.; Issa, Shams A. M.; Zakaly, Hesham M. H.
    In this work, the calcium-lead arseborate glass's basic components were doped with an equal amounts of NiCl2 and CoCl2, separately, to obtain two different glass samples that were dubbed the Ni-doped sample and the Co-doped sample. The fast quenching method was used to prepare that samples, while UV-vis and X-ray diffraction (XRD) patterns were used to characterize them. The XRD patterns of Ni-doped and Co-doped glass samples reveal amorphous structures with short-range order. While both contain similar components, nickel and cobalt additions result in distinct diffraction humps. The Ni-doped sample exhibits wider transmission windows and sharper band edges compared to the Co-doped sample. Additionally, Ni-doped glass shows higher maximum absorbance, suggesting suitability for energy storage, while Co-doped glass is better for UV-blocking applications. The absorption index, crucial for light-matter interaction, reflects optical relaxation processes and is influenced by material composition and structure. Dielectric loss factors were determined using the Drude-Lorentz model, highlighting the importance of understanding absorption index and optical relaxation in materials science. The resonance frequency of Co-doped glass is lower than that of Ni-doped glass, resulting in the absorption index and dielectric loss reaching their maxima at lower energy values for Co-doped glass. Furthermore, the Plasmon frequency in Co-doped glass is higher than in Ni-doped glass, indicating its superior ability to screen incident photons. Additionally, the scattering time for Co-doped glass is lower than for Ni-doped glass, suggesting that the Ni-doped sample has larger interatomic distances.
  • Küçük Resim Yok
    Öğe
    Shedding light on and comparing three different mathematical models of the optical conductivity concept
    (Elsevier Ltd., 2025) Alharshan, Gharam A.; Saudi, H.A.; Issa, Shams A.M.; Zakaly, Hesham M.H.; Gomaa, Hosam M.
    The optical response in materials offers valuable insights into their properties, especially regarding interband transitions, distinct from direct current responses. By adjusting the frequency of electromagnetic radiation, interband transitions and energy band mappings can be explored, even in materials like graphene. Optical conductivity, which measures a material's ability to conduct electricity under the influence of light, is pivotal across physics, materials science, and engineering. It quantifies a material's efficiency in absorbing and transporting electromagnetic energy as photons. Typically described by Drude's model, optical conductivity has applications in diverse fields, from designing specific optical properties in materials to optimizing solar cells and developing photonic devices. Plasmonics, meta-materials, and renewable energy research also benefit from understanding and controlling optical conductivity. The optical conductivity problem centers on comprehending materials’ electrical interactions with light across the optical spectrum, which is vital for various technologies. Theoretical models, simulations, and experiments address this problem, aiming to develop tunable materials and enhance theoretical models for accurate prediction of optical properties. Mathematical models, such as Maxwell's equations, the Lorentz-Drude model, and the Hosam-Heba model, elucidate optical conductivity, aiding in understanding light-material interactions and predicting material behavior under electromagnetic radiation. Each model offers a unique perspective on optical conductivity, with different theoretical foundations and mathematical formulations that can be applied depending on the specific properties of the material being studied. Understanding and manipulating optical conductivity is foundational to utilizing light across various technological applications. © 2024 Elsevier Ltd