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  • Документ
    Spectral Features of a Multi-Periodical Metamaterials
    (2019) Girich, A.; Kharchenko, A.; Tarapov, S.
    We numerically investigate the spectral properties of multi-periodic metamaterials of various configurations (the planar double-periodic photonic crystal and the bulk double-periodic magnetophotonic crystal) in the frequency range 15-45 GHz. In the first part of this paper we describe investigation of structure of the planar double periodic photonic crystal (PDPPC) which consists of two planar photonic crystals with large and small periods. A PDPPC unit cell consists of a series-connected narrow and wide segments of a microstrip transmission line. In the second part of this paper we will discuss results of investigation of a double-periodic magnetophotonic crystal (DPMPC) which consists of 3 unit cells. Each cell consists of periodically located 9 dielectric layers of quartz and teflon. On the border of the cell there is one layer of ferrite. We showed that both for a PDPPC and for a DPMPC in the transmission spectrum of these structures under study, a number of features arise: namely, narrow transmission peaks caused by the superposition of two spectra (with large and small periods) are observed in the stop bands of the spectrum. Such features may further allow the creation of a narrow-band filter for several frequencies for both planar structures and bulk ones.
  • Документ
    Точечная коррекция рассеянного светового поля плоской решетки диэктрических резонансных наносфер
    (ХНУРЭ, 2012) Гвинджилия, Г. Г.
    Solutions of the problem on electromagnetic waves scattering on a flat grate of resonant spheres were considered
  • Документ
    Hydroxyl radical scavenging activity of titanium oxide nanocrystals
    (2022) Maksimchuk, P.; Hubenko, K.; Seminko, V.; Onishchenko, A.; Bespalova, I.; Onishchenko, A.; Prokopiuk, V.; Tkachenko, A.; Yefimova, S.
  • Документ
    Reactive Oxygen Species Scavenging by Small Gadolinium-Yttrium Orthovanadate Nanocrystals
    (2022) Maksimchuk, P.; Hubenko, K.; Seminko, V.; Onishchenko, A.; Aslanov, A.; Klochkov, V.
    Oxidative stress induced by reactive oxygen species (hydrogen peroxide, superoxide anion, hydroxyl radical etc.) is the key factor in developing a variety of pathological conditions including diabetes, asthma, atherosclerosis, hypertension mellitus and cancer. To prevent or reduce the cell damages caused by reactive oxygen species, natural or synthetic molecules named antioxidants are commonly used. Recently, various inorganic nanomaterials, such as CeO2, Mn3O4, Co3O4 and Fe3O4 nanocrystals, have attracted growing interest as nano-antioxidants with reactive oxygen species regulating ability. Here, we report on high antioxidant behavior of small gadolinium-yttrium orthovanadate nanocrystals revealed by spectroscopic methods using various reactive oxygen species sensors, and propose the mechanism describing their reactive oxygen species scavenging action. It has been found that in 2 nm gadolinium-yttrium orthovanadate nanocrystals more than 60% vanadium ions are presented in lower V4+ and V3+ oxidation states. Switching between V3+↔V4+ and V4+↔V5+ oxidation states allow gadolinium-yttrium orthovanadate nanocrystals to react with hydrogen peroxide (H2O2) and superoxide anion (O2 •-) in enzyme-like manner and neutralize hydroxyl radical (•OH), and peroxyl radicals (ROO•), as well. The obtained data and proposed mechanism of gadoliniumyttrium orthovanadate nanocrystals antioxidant action can explain the non-trivial anti-aging and radioprotective effects of gadolinium-yttrium orthovanadate nanocrystals observed earlier in vivo.
  • Документ
    Hydroxyl radicals scavenging by small oxide | nanocrystals with variable valence ions
    (Nanocomposites and Nanomaterials, 2022) Maksimchuk, P.; Hubenko, K.; Seminko, V.; Onishchenko, A.; Bespalova, I.; Klochkov, V.; Yefimova, S.