5,622 research outputs found
Tunnelling Studies of Two-Dimensional States in Semiconductors with Inverted Band Structure: Spin-orbit Splitting, Resonant Broadening
The results of tunnelling studies of the energy spectrum of two-dimensional
(2D) states in a surface quantum well in a semiconductor with inverted band
structure are presented. The energy dependence of quasimomentum of the 2D
states over a wide energy range is obtained from the analysis of tunnelling
conductivity oscillations in a quantizing magnetic field. The spin-orbit
splitting of the energy spectrum of 2D states, due to inversion asymmetry of
the surface quantum well, and the broadening of 2D states at the energies, when
they are in resonance with the heavy hole valence band, are investigated in
structures with different strength of the surface quantum well. A quantitative
analysis is carried out within the framework of the Kane model of the energy
spectrum. The theoretical results are in good agreement with the tunnelling
spectroscopy data.Comment: 29 pages, RevTeX, submitted in Phys.Rev.B. Figures available on
request from [email protected]
Oscillation Caused By Impulses
AbstractThe present paper is devoted to the investigation of the oscillation of a kind of very extensively studied second order nonlinear delay differential equations with impulses, some interesting results are obtained, which illustrate that impulses play a very important role in giving rise to the oscillations of equations
Phase description of oscillatory convection with a spatially translational mode
We formulate a theory for the phase description of oscillatory convection in
a cylindrical Hele-Shaw cell that is laterally periodic. This system possesses
spatial translational symmetry in the lateral direction owing to the
cylindrical shape as well as temporal translational symmetry. Oscillatory
convection in this system is described by a limit-torus solution that possesses
two phase modes; one is a spatial phase and the other is a temporal phase. The
spatial and temporal phases indicate the position and oscillation of the
convection, respectively. The theory developed in this paper can be considered
as a phase reduction method for limit-torus solutions in infinite-dimensional
dynamical systems, namely, limit-torus solutions to partial differential
equations representing oscillatory convection with a spatially translational
mode. We derive the phase sensitivity functions for spatial and temporal
phases; these functions quantify the phase responses of the oscillatory
convection to weak perturbations applied at each spatial point. Using the phase
sensitivity functions, we characterize the spatiotemporal phase responses of
oscillatory convection to weak spatial stimuli and analyze the spatiotemporal
phase synchronization between weakly coupled systems of oscillatory convection.Comment: 35 pages, 14 figures. Generalizes the phase description method
developed in arXiv:1110.112
Oscillatory criteria for Third-Order difference equation with impulses
AbstractIn this paper, we investigate the oscillation of Third-order difference equation with impulses. Some sufficient conditions for the oscillatory behavior of the solutions of Third-order impulsive difference equations are obtained
Multi-physics phenomena influencing the performance of the car horn
Usually cars are equipped with disk horns. In these devices electromagnetic energy is converted into mechanical energy
of two nuclei that vibrate and impact each other \u2013 the impacts excite the disk that radiates sound. This paper aims at
understanding the results of acoustic tests carried out on horns with different excitation voltages and different mounting
brackets. Since many non-linear phenomena are inherent in the vibrations of the nuclei, a detailed model of the
electromechanical system is developed. Results show the dependence of operating frequency on the input voltage
and the role played by the various mechanical and electrical parameters on the dynamics of the horn. Particular nonlinear
effects, like sub-harmonic excitation, are presented and discussed. A general agreement between experimental
results and numerical simulations is found
Spike-Train Responses of a Pair of Hodgkin-Huxley Neurons with Time-Delayed Couplings
Model calculations have been performed on the spike-train response of a pair
of Hodgkin-Huxley (HH) neurons coupled by recurrent excitatory-excitatory
couplings with time delay. The coupled, excitable HH neurons are assumed to
receive the two kinds of spike-train inputs: the transient input consisting of
impulses for the finite duration (: integer) and the sequential input
with the constant interspike interval (ISI). The distribution of the output ISI
shows a rich of variety depending on the coupling strength and the
time delay. The comparison is made between the dependence of the output ISI for
the transient inputs and that for the sequential inputs.Comment: 19 pages, 4 figure
Oscillation of forced impulsive differential equations with -Laplacian and nonlinearities given by Riemann-Stieltjes integrals
In this article, we study the oscillation of second order forced impulsive differential equation with -Laplacian and nonlinearities given by Riemann-Stieltjes integrals of the form
\begin{equation*}
\left( p(t)\phi _{\gamma }\left( x^{\prime }(t)\right) \right) ^{\prime}+q_{0}\left( t\right) \phi _{\gamma }\left( x(t)\right)+\int_{0}^{b}q\left( t,s\right) \phi _{\alpha \left( s\right) }\left(x(t)\right) d\zeta \left(s\right) =e(t), t\neq \tau _{k},
\end{equation*}
with impulsive conditions
\begin{equation*}
x\left( \tau _{k}^{+}\right) =\lambda _{k}~x\left( t_{k}\right), x^{\prime }\left( \tau _{k}^{+}\right) =\eta _{k}~x^{\prime }\left( \tau_{k}\right),
\end{equation*}
where \phi _{\gamma }\left( u\right) :=\left\vert u\right\vert ^{\gamma } \mbox{{\rm sgn}\,}u, is strictly increasing such that , and is the the impulsive moments sequence. Using the Riccati transformation technique, we obtain sufficient conditions for this equation to be oscillatory
- …