scholarly journals The Magnetic Response of Starphenes

Chemistry ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 1381-1391
Author(s):  
Mesías Orozco-Ic ◽  
Gabriel Merino

The aromaticity of [n]starphenes (n = 1, 4, 7, 10, 13, 16), as well as starphene-based [19]dendriphene, is addressed by calculating the magnetically induced current density and the induced magnetic field, using the pseudo-π model. When an external magnetic field is applied, these systems create diatropic currents that split into a global peripheral current surrounding the starphene skeleton and several local currents in the acene-based arms, resulting in large shielding cones above the arms. In particular, the arm currents are smaller than their linear analogs, and in general, the strengths of the ring currents tend to weaken as the starphene get larger.

2021 ◽  
Author(s):  
Dage Sundholm ◽  
Maria Dimitrova ◽  
Raphael Berger

We give an overview of the molecular response to an external magnetic field perturbing quantum mechanical systems. We present state-of-the-art methods for calculating magnetically-induced current-density susceptibilities. We discuss the essence...


2017 ◽  
Vol 22 (3) ◽  
pp. 567-582 ◽  
Author(s):  
B.K. Jha ◽  
B. Aina

AbstractThe present work presents a theoretical investigation of an MHD mixed convection flow in a vertical microchannel formed by two electrically non-conducting infinite vertical parallel plates. The influence of an induced magnetic field arising due to motion of an electrically conducting fluid is taken into consideration. The governing equations of the motion are a set of simultaneous ordinary differential equations and their exact solutions in dimensionless form have been obtained for the velocity field, the induced magnetic field and the temperature field. The expressions for the induced current density and skin friction have also been obtained. The effects of various non-dimensional parameters such as rarefaction, fluid wall interaction, the Hartmann number and the magnetic Prandtl number on the velocity, the induced magnetic field, the temperature, the induced current density, and skin friction have been presented in a graphical form. It is found that the effect of the Hartmann number and magnetic Prandtl number on the induced current density is found to have a decreasing nature at the central region of the microchannel.


2019 ◽  
Vol 55 (6) ◽  
pp. 1-5 ◽  
Author(s):  
Lyes Ifrek ◽  
Olivier Chadebec ◽  
Sebastien Rosini ◽  
Gilles Cauffet ◽  
Yann Bultel ◽  
...  

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Hasan Nihal Zaidi ◽  
Mohammed Yousif ◽  
S. Nazia Nasreen

The study scrutinizes the effects of thermal radiation, heat generation, and induced magnetic field on steady, fully developed hydromagnetic free convection flow of an incompressible viscous and electrically conducting couple stress fluid in a vertical channel. The channel walls are maintained at an isoflux-isothermal condition, such that the left channel wall is maintained at a constant heat flux. In contrast, the right channel wall is maintained at a constant temperature. The governing simultaneous equations are solved analytically utilizing the method of undetermined coefficient, and closed form solutions in dimensionless form have been acquired for the velocity field, the induced magnetic field, and the temperature field. The expression for the induced current density has been also obtained. A parametric study for the velocity, temperature, and induced magnetic field profiles, as well as for the skin-friction coefficient, Nusselt number, and induced current density, is conducted and discussed graphically.


2020 ◽  
pp. 174751982095860
Author(s):  
Mina Sakuragi ◽  
Yoshikazu Takahashi ◽  
Keito Ehara ◽  
Katsuki Kusakabe

The aim of this study is to develop self-standing, ultrathin film, nanosheets with high magnetic response for use in a medical device that can be migrated to a target location in the body by using an external magnetic field. First, iron oxide nanoparticles are synthesized by either the sol-gel method or thermal decomposition. The resulting magnetic properties of the nanoparticles show that the thermal decomposition method provides a greater saturation magnetization value than the sol-gel method. Next, the nanoparticles obtained by the thermal decomposition method are embedded into nanosheets of poly(L-lactide) at varying concentrations. Embedding of the nanoparticles in the composite nanosheets is achieved by the application of an external magnetic field. The composite nanosheets are then characterized. The thickness of the nanosheet increases, and the nanoparticles are well dispersed, with an increase in poly (L-lactide) concentration. The NP-embedded nanosheets are imaged by transmission electron microscopy, which reveals thin, long aggregates aligned in collinear line features. X-ray diffraction results indicate that the magnetic hard axis of the nanoparticles in the nanosheets is aligned in parallel to the plane of the nanosheet by magnetic field application during nanosheet preparation. In addition, the nanosheets at high poly (L-lactide) concentrations that had been subjected to a magnetic field during preparation show a slightly greater magnetic response compared with both nanosheets without magnetic field exposure and nanosheets prepared at low poly (L-lactide) concentrations.


1997 ◽  
Vol 12 (12) ◽  
pp. 877-886 ◽  
Author(s):  
Vadim Zeitlin

We are studying finite fermion density states in Maxwell QED 2+1 with external magnetic field. It is shown that at any fermion density the energy of some magnetized states may be less than that of the state with the same density, but no magnetic field. Magnetized states are described by the effective Maxwell–Chern–Simons QED 2+1 Lagrangian with gauge field mass proportional to the number of filled Landau levels.


2011 ◽  
Vol 89 (2) ◽  
pp. 201-212 ◽  
Author(s):  
Kh. S. Mekheimer ◽  
Mohammed H. Haroun ◽  
M. A. El Kot

A mathematical model for blood flow through an elastic artery with overlapping stenosis under the effect of induced magnetic field is presented. The present theoretical model may be considered as a mathematical representation to the movement of conductive physiological fluid through coaxial tubes such that the inner tube is uniform and rigid, representing a catheter tube, while the outer tube is an anisotropically tapered elastic cylindrical tube filled with a viscous incompressible electrically conducting fluid, representing blood. The analysis is carried out for an artery with mild local narrowing in its lumen, forming a stenosis. Analytical expressions for the stream function, the magnetic force function, the axial velocity, the axial induced magnetic field, and the distribution of the current density are obtained. The results for the resistance impedance, the wall shear stress distribution, the axial velocity, the axial induced magnetic field, and distribution of the current density have been computed numerically, and the results were studied for various values of the physical parameters, such as the the Hartmann number Ha, the magnetic Reynolds number Rm, the taper angle ϕ, the maximum height of stenosis δ, the degree of anisotropy of the vessel wall n, and the contributions of the elastic constraints to the total tethering K.


2021 ◽  
Vol 63 (8) ◽  
pp. 1035
Author(s):  
П.И. Безотосный ◽  
К.А. Дмитриева

The results of calculating the temperature dependences of the critical current density and critical magnetic field of thin inhomogeneous superconducting films are presented. Comparison of the results obtained for inhomogeneous films with the results of calculations for homogeneous ones showed that in both cases, the decrease in the critical magnetic field occurs according to the root law, and the critical current density changes according to a power law with a degree of 3/2 when approaching the critical temperature. Quantitatively, the critical current density for inhomogeneous films in the absence of an external magnetic field is lower than for homogeneous ones. In turn, the critical magnetic field of inhomogeneous films is much larger than the critical field of homogeneous films.


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