Science for Education

In this paper we study the bifurcational mechanisms of synchronization and multistability formation in a system of two interacting van der Pol oscillators, one of which is under external harmonic forcing. We draw a two­parametric bifurcation diagram for phasereduced system and study its evolution in transition from symmetrical to asymmetrical repulsive interaction. Relying on the results of bifurcation analysis of non­reduced system we conclude that the synchronization scenarios found in the phase­reduced system correspond to the ones in the non­reduced system.

A test of hyperbolic nature of chaotic attractors, based on an analysis of statistics distribution of angles between stable and unstable subspaces, is applied to reduced finite­dimensional models of distributed systems which are the modifications of the Swift–Hohenberg equation and Brusselator model, as well as to the problem of parametric excitation of standing waves by the modulated pump.

The model of two field­coupled spin­transfer oscillators has been derived and studied. It has been shown that this model demonstrates phase synchronization in a wide bandwidth, quasiperiodic oscillations and chaos.

There are introduced ferromagnetic periodic structures consist of two coupled magnonic crystals and related magnonic and crystal film, separated by a dielectric layer. The dispersion equation made for magnetostatic waves, that propagate in such structures and identified main features of formation band gaps and a comparison with a periodic structure of one magnonic crystal was made.

Design of a diode oscillator with a field­emission cathode placed in a photonic crystal (PC) resonator is described. Results of numerical calculation of basic electrodynamic parameters of the PC resonator are presented. The 3D electrodynamic simulation by using the modern software package HFSS shows that varying the design of the energy output allows control of the loaded Q­factor in a wide range. Selection of the optimal value of the loaded Q­factor provides rather high output power and efficiency for reasonable values of the field­emission cathode current density.

The paper presents the results of the experimental research ultra­wide range s­band chaos generator based on TWT. The effect of absolute suppression mode chaotic signal by external harmonic signal has been investigated.

This paper is devoted to the three­dimensional numerical simulation of the «compressed» state of the relativistic electron beam in two­section vircator system with drift tubes with different diameters. We have discovered the mechanism of formation of the «compressed» state of the relativistic beam through the formation of two virtual cathode near the anode grid and between connected sections, which will eventually merged into one distributed in the drift space virtual cathode (compressed state of the beam).

The problems of perception, significance of numerical assessments of scientific publications quality, copyright protection are considered. Examples from the history of science are given. Ethical issues by using electronic scientific databases are named.

The problems of perception, significance of numerical assessments of scientific publications quality, copyright protection are considered. Examples from the history of science are given. Ethical issues by using electronic scientific databases are named.

The purpose of this article is to increase the interest of school students in General physics. For notice teacher it will help to illustrate Newton’s laws, Archimed’s law and Pascale’s law by simple home experiments.