scholarly journals Effect of interparticle interaction on magnetic hyperthermia: homogeneous spatial distribution of the particles

2019 ◽  
Vol 377 (2143) ◽  
pp. 20180216 ◽  
Author(s):  
Ali Fathi Abu-Bakr ◽  
Andrey Zubarev
Keyword(s):  
Spatial Distribution ◽  
Magnetic Moment ◽  
Characteristic Time ◽  
Theoretical Study ◽  
Magnetic Hyperthermia ◽  
Interparticle Interaction ◽  
Theme Issue ◽  
Internal Structures ◽  
Linearly Polarized ◽  
Magnetite Particles

The paper deals with the theoretical study of the effect of magnetic interparticle interaction on magnetic hyperthermia, produced by the particles under the action of a linearly polarized oscillating field. The particles are homogeneously distributed and immobilized in a rigid medium. The supposed size of the magnetite particles is about 20–30 nm. For these particles, the characteristic time of the Neel remagnetization is much longer than the time of observation. This is why we concluded that the dissipation occurs as a result of the particle magnetic moment oscillation in the pit of energy of magnetic anisotropy. This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.

scholarly journals Effect of internal chain-like structures on magnetic hyperthermia in non-liquid media

2019 ◽  
Vol 377 (2143) ◽  
pp. 20180213 ◽  
Author(s):  
Andrey Yu. Zubarev
Keyword(s):  
Theoretical Study ◽  
Linear Chain ◽  
Particle Diameter ◽  
Magnetic Hyperthermia ◽  
Heating Time ◽  
Theme Issue ◽  
Magnetic Medium ◽  
Internal Structures ◽  
Magnetite Particles ◽  
Process Observation

This paper deals with a theoretical study of the effect of chain-like aggregates on magnetic hyperthermia in systems of single-domain ferromagnetic particles immobilized in a non-magnetic medium. We assume that the particles form linear chain-like aggregates and the characteristic time of the Néel remagnetization is much longer than the time of medium heating (time of process observation). This is applicable to magnetite particles when the particle diameter exceeds 20–25 nm. Our results show that the appearance of the chains significantly decreases the intensity of heat production. This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.

scholarly journals On the theory of magnetic hyperthermia: clusterization of nanoparticles

2020 ◽  
Vol 378 (2171) ◽  
pp. 20190251 ◽  
Author(s):  
Ali F. Abu-Bakr ◽  
Andrey Yu. Zubarev
Keyword(s):  
Mathematical Modelling ◽  
Magnetic Anisotropy ◽  
Heat Production ◽  
Theoretical Study ◽  
Magnetic Hyperthermia ◽  
Strong Anisotropy ◽  
Theme Issue ◽  
Weak Anisotropy ◽  
Host Medium ◽  
Ferromagnetic Particles

Experiments show that clusters consisting of nano-sized ferromagnetic particles strongly affect the intensity of heat production during magnetic hyperthermia. In this paper, a theoretical study and mathematical modelling of the heat production by clusters of single-domain ferromagnetic particles, immobilized in a host medium, are presented. Two situations of strong and weak magnetic anisotropy of the particles are considered. Our results show that, in the case of strong anisotropy, the clusterization weakens the thermal effect, whereas in the case of weak anisotropy it enhances it. This article is part of the theme issue ‘Patterns in soft and biological matters'.

scholarly journals The Effect of Particle Concentration on the Heating Rate of Ferrofluids for Magnetic Hyperthermia

2015 ◽  
Vol 58 (1) ◽  
pp. 81-88 ◽  
Author(s):  
I. Malaescu ◽  
C. N. Marin ◽  
M. Bunoiu ◽  
P. C. Fannin ◽  
N. Stefu ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Oleic Acid ◽  
Dilution Rate ◽  
Heating Rate ◽  
Particle Concentration ◽  
Magnetic Hyperthermia ◽  
Initial Sample ◽  
Frequency Field ◽  
Three Samples ◽  
Magnetite Particles

Abstract The complex magnetic susceptibility χ(f) = χ′(f) - i χ″(f), of a ferrofluid sample with magnetite particles dispersed in kerosene and stabilized with oleic acid, over the range 0.1 GHz to 6 GHz, was determined. The initial sample has been successively diluted with kerosene (with a dilution rate of 2/3), thus obtaining further three samples. Using the complex magnetic susceptibility measurements of each sample, the frequency field and particle concentration dependencies of the heating rate of the ferrofluid samples, were analyzed. The results show the possibility of using the heating rate of ferrofluid samples with different particle concentrations, in hyperthermia applications.

scholarly journals Magnetic Field Instability of a Plasma in a Beam of Electromagnetic Radiation

1980 ◽  
Vol 35 (4) ◽  
pp. 461-463 ◽  
Author(s):  
O. M. Gradov ◽  
L. Stenflo
Keyword(s):  
Magnetic Field ◽  
Spatial Distribution ◽  
Magnetic Fields ◽  
Field Strength ◽  
Electromagnetic Radiation ◽  
Characteristic Time ◽  
Incident Radiation ◽  
Maximum Value ◽  
Quasi Stationary State ◽  
The Magnetic Field

Abstract A beam of electromagnetic radiation can generate magnetic fields in plasmas. It is shown that those fields grow significantly when the incident radiation is sufficiently strong. We obtain expressions for the characteristic time of the growth of the fields as well as for their spatial distribution and point out a possible mechanism, which can lead to the formation of a quasi-stationary state. The maximum value of the magnetic field strength is estimated

Odd–even harmonic generation from oriented CO molecules in linearly polarized laser fields and the influence of the dynamic core-electron polarization

2019 ◽  
Vol 21 (43) ◽  
pp. 24177-24186 ◽  
Author(s):  
Ngoc-Loan Phan ◽  
Cam-Tu Le ◽  
Van-Hung Hoang ◽  
Van-Hoang Le
Keyword(s):  
Harmonic Generation ◽  
Theoretical Study ◽  
Polar Molecule ◽  
Time Dependent ◽  
Laser Fields ◽  
Core Electron ◽  
Electron Polarization ◽  
Linearly Polarized ◽  
Active Electron ◽  
Even Harmonics

We present a detailed theoretical study of the odd–even harmonics generated from the polar molecule CO by the method based on numerically solving the time-dependent Schrödinger equation within the single-active-electron approximation.

scholarly journals Radiation forces study of a Laguerre Gaussian beam type TEM∗01 on a dielectric sphere in the Rayleigh scattering regime

DYNA ◽  
2019 ◽  
Vol 86 (210) ◽  
pp. 187-193
Author(s):  
Darby Paez Amaya ◽  
Martha Lucía Molina Prado ◽  
Néstor Alonso Arias Hernández
Keyword(s):  
Rayleigh Scattering ◽  
Theoretical Study ◽  
Optical Tweezer ◽  
Phenomenological Analysis ◽  
Dielectric Sphere ◽  
Radiation Forces ◽  
Linearly Polarized ◽  
Beam Type ◽  
High Level ◽  
Mode Tem

From the invention of the Optical Tweezer (OT) in 1986, these devices have been considered as high-level tools for research in the areas such as biology and microbiology. A theoretical study obtaining equations for gradient and scattering forces that exert an OT when the illumination beam is a doughnut-shaped mode TEM∗01 linearly polarized is realized. This work focuses on the behavior of radiation forces on a dielectric sphere in the Rayleigh regime. In order to facilitate the phenomenological analysis of the behavior of the radiation forces a graphical user interface is created.

Characteristic Time of Oxygen: Calculations and Theoretical Study

1976 ◽  
Vol EI-11 (1) ◽  
pp. 28-32
Author(s):  
Abdel-rahman M. Zaghlous ◽  
Roshdy M. Radwan ◽  
Mohamed S. Abou-seada
Keyword(s):  
Characteristic Time ◽  
Theoretical Study
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