Персона: Усов, Николай Александрович
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Инженерно-физический институт биомедицины
Цель ИФИБ и стратегия развития – это подготовка высококвалифицированных кадров на базе передовых исследований и разработок новых перспективных методов и материалов в области инженерно-физической биомедицины. Занятие лидерских позиций в биомедицинских технологиях XXI века и внедрение их в образовательный процесс, что отвечает решению практикоориентированной задачи мирового уровня – диагностике и терапии на клеточном уровне социально-значимых заболеваний человека.
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Николай Александрович
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- ПубликацияТолько метаданныеDynamics of particles with cubic magnetic anisotropy in a viscous liquid(2022) Rytov, R. A.; Gubanova, E. M.; Usov, N. A.; Губанова, Елизавета Михайловна; Усов, Николай Александрович© 2021 Elsevier B.V.We calculated the specific absorption rate (SAR) and relaxation time of a dilute assembly of spherical iron nanoparticles with cubic anisotropy distributed in a viscous liquid. The behavior of unit magnetization vector was investigated by the solution of stochastic Landau–Lifshitz equation. The spatial orientation of magnetic nanoparticle was determined by the set of stochastic equations for multiple particle directors. The particle viscous and magnetic magnetization reversal modes are revealed at low and sufficiently high amplitudes of alternating magnetic field, respectively. The SAR of iron nanoparticle assembly is shown to exceed significantly that of iron oxide nanoparticles with uniaxial anisotropy at the same amplitudes and frequencies of applied magnetic field. The linear response theory is shown to be valid only at small magnetic field amplitudes, H0 ≤ 50–70 Oe.
- ПубликацияТолько метаданныеA shape visualization of a magnetic anisotropy energy density of single-domain magnetic nanoparticles(2020) Rytov, R. A.; Usov, N. A.; Усов, Николай Александрович© 2020 National Research Nuclear University. All rights reserved.A key physical parameter determining stationary directions of a magnetic moment of a single-domain ferromagnetic nanoparticle is a type of its effective magnetic anisotropy. Sta-tionary directions of a magnetic moment of a particle change under an influence of an exter-nal magnetic field. For better understanding of a behavior of a magnetic moment of a nano-particle in an external magnetic field, we proposed a simple method for visualization of an energy density of magnetic anisotropy of a single-domain magnetic nanoparticle. In a spheri-cal coordinate system, an energy density of magnetic anisotropy is represented as a certain surface, which makes it possible to clearly demonstrate the presence of energy minima that determine the equilibrium directions of a single vector of magnetization of a nanoparticle in space. The cases of uniaxial, cubic, and combined magnetic anisotropy are considered in de-tail. The change in the total energy of a magnetic nanoparticle under the influence of an ex-ternal uniform magnetic field is demonstrated.
- ПубликацияТолько метаданныеMagnetostatic properties of assembly of magnetic vortices(2020) Bautin, V. A.; Perov, N. S.; Rytov, R. A.; Gubanova, E. M.; Usov, N. A.; Губанова, Елизавета Михайловна; Усов, Николай Александрович© 2019The ultrasonic oscillation of a macroscopic sample in a viscous liquid is used to create magnetic particles of FeCo alloy with an average diameter D ~100 nm. The FeCo particles obtained have a high specific saturation magnetization, Ms = 1960 emu/cm3, close to that of a bulk sample. The hysteresis loop of a magneto-polymer composite prepared from FeCo particles shows low coercive force and a remanent magnetization close to zero. The magnetic saturation of the magnetic composite samples is achieved in a sufficiently strong magnetic field, H = 6.5 kOe. The hysteresis loop features of the magnetic composite have been explained by means of the numerical simulation of the quasistatic hysteresis loops of non-oriented dilute assemblies of spheroidal FeCo particles with various aspect ratios.