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

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

THERMODYNAMIC STABILITY OF THE GaFeAs SYSTEM

Using the self-consistent field theory implemented in the Quantum Espresso program, concentration intervals of stable (Fe concentration over 65 at.%), unstable (less than 35 at.%), and metastable (35–65 at.%) states of the GaFeAs system at temperatures of 100–1000 K were established.Работа была выполнена при финансовой поддержке гранта Президента РФ МК-265.2022.1.2

Delayed behavioral and neurochemical effects of anti-glutamate antibodies in aging C57BL/6 mice

We analyzed delayed effect of intranasal administration of anti-glutamate antibodies on mnestic function and tissue concentrations of neurotransmitters in the hippocampus and prefrontal cortex in aging C57BL/6 mice. It was found that after 14-day administration of anti-glutamate antibodies, improvement of the passive avoidance conditioning persisted for 7 days after the treatment was discontinued. In 7 days after discontinuation of treatment, increased content of dopamine and its metabolites as well as aspartic acid and taurine was observed in the hippocampus of mice treated with anti-glutamate antibodies. In the prefrontal cortex, administration of anti-glutamate antibodies had no effect on the levels of neurotransmitters, but increased the concentration of glutamate