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 метаданныеQuasistatic hysteresis loops of magnetic nanoparticles in a rotating magnetic field(2020) Usov, N. A.; Gubanova, E. M.; Epstein, N. B.; Belyaeva, G. A.; Oleinikov, V. A.; Усов, Николай Александрович; Губанова, Елизавета Михайловна; Эпштейн, Наталья Борисовна; Олейников, Владимир Александрович© 2019Quasistatic hysteresis loops of a single-domain magnetic nanoparticle with uniaxial anisotropy in a rotating magnetic field have been calculated. Magnetic hysteresis is shown to exist only in a limited range of reduced magnetic field amplitudes, 0.5 < h0 < 1, where h0 = H0/Ha, H0 is the amplitude of the rotating magnetic field, Ha being the particle anisotropy field. An analytical formula is obtained for the particle coercive force as a function of the reduced field amplitude. In the domain h0 < 0.5 the magnetization reversal of a particle is impossible, since the final energy barrier exists between the potential wells of the particle for all orientations of applied magnetic field. On the other hand, in the domain h0 > 1 the total energy of the nanoparticle has a single energy minimum, so that there is no magnetic hysteresis. Quasistatic hysteresis loops of a randomly oriented assembly of non interacting nanoparticles in a rotating magnetic field are also obtained.
- ПубликацияТолько метаданныеThe heating of magnetic nanoparticles in a rotating magnetic field(2020) Serebryakova, O. N.; Usov, N. A.; Gubanova, E. M.; Усов, Николай Александрович; Губанова, Елизавета Михайловна© 2019, © 2019 Taylor & Francis.The specific absorption rate of magnetic nanoparticles in a rotating magnetic field has been calculated taking into account both thermal fluctuations of the particle magnetic moments and strong magneto-dipole interactions in nanoparticle clusters with various filling factors. For an assembly of interacting superparamagnetic nanoparticles, the maximal values of the specific absorption rate in a rotating magnetic field are found to be 30–40% greater than that in alternating magnetic field. In addition, for the given filling factor and magnetic field amplitude in rotating magnetic field the nanoparticles in a wider range of diameters can effectively contribute to the energy absorption process. Therefore, the use of rotating magnetic field seems preferable in magnetic nanoparticle hyperthermia.
- 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.
- 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 метаданныеHeating ability of elongated magnetic nanoparticles(2021) Gubanova, E. M.; Usov, N. A.; Oleinikov, V. A.; Губанова, Елизавета Михайловна; Усов, Николай Александрович; Олейников, Владимир АлександровичLow-frequency hysteresis loops and specific absorption rate (SAR) of various assemblies of elongated spheroidal magnetite nanoparticles have been calculated for a range of particle semiaxis ratios a/b = 1.0-3.0. The SAR of a dilute randomly oriented assembly of magnetite nanoparticles in an alternating magnetic field of moderate frequency, f = 300 kHz, and amplitude H0 = 100-200 Oe is shown to decrease significantly with an increase in the aspect ratio of nanoparticles. In addition, there is a narrowing and shift of the intervals of optimal particle diameters towards smaller particle sizes. However, the orientation of a dilute assembly of elongated nanoparticles in a magnetic field leads to an almost twofold increase in SAR at the same frequency and amplitude of the alternating magnetic field, the range of optimal particle diameters remaining unchanged. The effect of the magneto-dipole interaction on the SAR of a dilute assembly of oriented clusters of elongated magnetite nanoparticles has also been investigated depending on the volume fraction of nanoparticles in a cluster. It has been found that the SAR of the assembly of oriented clusters decreases by approximately an order of magnitude with an increase in the volume fraction of nanoparticles in a cluster in the range of 0.04-0.2.