this paper considers the problem of stable limit cycles generating in a class of uncertain nonlinear systems which leads to stable oscillations in the system’s output.this is a wanted behavior in many practical engineering problems. for this purpose, first the equation of the desirable limit cycle is achieved according to shape, amplitude and frequency of the required output oscillations. then,...

In this paper, we study the electronic properties of a concentric triple quantum ring using exact diagonalization technique. The energy spectra and magnetization for a single electron and two electrons, in the presence of an applied magnetic field, are calculated and discussed. It is shown that, for two-interacting electrons, the period of Aharonov-Bohm oscillations decreases to the half of tha...

Article presents results of study on possibility of increasing the efficiency of drilling directional straight sections of wells using screw downhole motors (SDM) with a combined method of drilling with rotation of drilling string (DS). Goal is to ensure steady-state operation of SDM with simultaneous rotation of DS by reducing the amplitude of oscillations with adjusting the parameters of dril...

in this paper, we study the electronic properties of a concentric triple quantum ring using exact diagonalization technique. the energy spectra and magnetization for a single electron and two electrons, in the presence of an applied magnetic field, are calculated and discussed. it is shown that, for two-interacting electrons, the period of aharonov-bohm oscillations decreases to the half of tha...

In this paper, a class of second order forced nonlinear differential equation is considered and several new oscillation theorems are obtained. Our results generalize and improve those known ones in the literature.

In this paper, we study the oscillation of certain higher-order neutral partial functional differential equations with the Robin boundary conditions. Some oscillation criteria are established. Two examples are given to illustrate the main results in the end of this paper.

We present a design framework that combines positive and negative feedback for robust stable oscillations in closed loop. The is initially based on graphical methods, to guide the selection of overall strength (gain) relative proportion (balance). then generalized via linear matrix inequalities. goal guarantee bounded dynamic uncertainties extend approach passive interconnections. results paper...