251 research outputs found
Multiple Scattering of Electromagnetic Waves by an Array of Parallel Gyrotropic Rods
We study multiple scattering of electromagnetic waves by an array of parallel
gyrotropic circular rods and show that such an array can exhibit fairly unusual
scattering properties and provide, under certain conditions, a giant
enhancement of the scattered field. Among the scattering patterns of such an
array at its resonant frequencies, the most amazing is the distribution of the
total field in the form of a perfect self-similar structure of chessboard type.
The scattering characteristics of the array are found to be essentially
determined by the resonant properties of its gyrotropic elements and cannot be
realized for arrays of nongyrotropic rods. It is expected that the results
obtained can lead to a wide variety of practical applications.Comment: 5 pages, 6 figure
Electromagnetic Oscillations in a Driven Nonlinear Resonator: A New Description of Complex Nonlinear Dynamics
Many intriguing properties of driven nonlinear resonators, including the
appearance of chaos, are very important for understanding the universal
features of nonlinear dynamical systems and can have great practical
significance. We consider a cylindrical cavity resonator driven by an
alternating voltage and filled with a nonlinear nondispersive medium. It is
assumed that the medium lacks a center of inversion and the dependence of the
electric displacement on the electric field can be approximated by an
exponential function. We show that the Maxwell equations are integrated exactly
in this case and the field components in the cavity are represented in terms of
implicit functions of special form. The driven electromagnetic oscillations in
the cavity are found to display very interesting temporal behavior and their
Fourier spectra contain singular continuous components. To the best of our
knowledge, this is the first demonstration of the existence of a singular
continuous (fractal) spectrum in an exactly integrable system.Comment: 5 pages, 3 figure
Analysis of a strip loop antenna located on the surface of an open cylindrical waveguide filled with a resonant magnetoplasma
The electrodynamic characteristics of a circular loop antenna located on
the surface of an open waveguide in the form of an axially magnetized
plasma column are studied using the integral equation method. The
current distribution and the input impedance of the antenna excited by a
time-harmonic external voltage are obtained in closed form for the case
where the plasma inside the column is resonant
Relief and geology of the north polar region of the planet Venus
Description of topographic features is given for the North polar region of the planet Venus. Principal geomorphic types of terrain are characterized as well as their geologic relations. Relative ages of geologic units in Venus North polar region are discussed
Effect of antibodies to glutamate on age-related memory changes in C57Bl/6 mice
Chronic intranasal administration of antibodies to glutamate to aging C57Bl/6 mice improved passive avoidance conditioning, had no effect on horizontal and vertical locomotor activity, but slowed locomotion in the open-field test. Administration of antibodies to glutamate increased the content of dopamine and its metabolites in mouse hippocampus, but had no effect on the metabolism of neurotransmitter amino acids. In the frontal cortex, antibodies to glutamate did not affect neurotransmitter metabolism, but increased the level of both excitatory and inhibitory amino acids without changing their ratio
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