988 research outputs found
Integrable Systems and Metrics of Constant Curvature
In this article we present a Lagrangian representation for evolutionary
systems with a Hamiltonian structure determined by a differential-geometric
Poisson bracket of the first order associated with metrics of constant
curvature. Kaup-Boussinesq system has three local Hamiltonian structures and
one nonlocal Hamiltonian structure associated with metric of constant
curvature. Darboux theorem (reducing Hamiltonian structures to canonical form
''d/dx'' by differential substitutions and reciprocal transformations) for
these Hamiltonian structures is proved
Impact of the North Atlantic thermohaline circulation on the European and Northern Atlantic weather in a coupled GCM simulation
Hydrodynamic chains and a classification of their Poisson brackets
Necessary and sufficient conditions for an existence of the Poisson brackets
significantly simplify in the Liouville coordinates. The corresponding
equations can be integrated. Thus, a description of local Hamiltonian
structures is a first step in a description of integrable hydrodynamic chains.
The concept of Poisson bracket is introduced. Several new Poisson brackets
are presented
Intrinsic defects in silicon carbide LED as a perspective room temperature single photon source in near infrared
Generation of single photons has been demonstrated in several systems.
However, none of them satisfies all the conditions, e.g. room temperature
functionality, telecom wavelength operation, high efficiency, as required for
practical applications. Here, we report the fabrication of light emitting
diodes (LEDs) based on intrinsic defects in silicon carbide (SiC). To fabricate
our devices we used a standard semiconductor manufacturing technology in
combination with high-energy electron irradiation. The room temperature
electroluminescence (EL) of our LEDs reveals two strong emission bands in
visible and near infrared (NIR), associated with two different intrinsic
defects. As these defects can potentially be generated at a low or even single
defect level, our approach can be used to realize electrically driven single
photon source for quantum telecommunication and information processing
Metric Fourier approximation of set-valued functions of bounded variation
We introduce and investigate an adaptation of Fourier series to set-valued
functions (multifunctions, SVFs) of bounded variation. In our approach we
define an analogue of the partial sums of the Fourier series with the help of
the Dirichlet kernel using the newly defined weighted metric integral. We
derive error bounds for these approximants. As a consequence, we prove that the
sequence of the partial sums converges pointwisely in the Hausdorff metric to
the values of the approximated set-valued function at its points of continuity,
or to a certain set described in terms of the metric selections of the
approximated multifunction at a point of discontinuity. Our error bounds are
obtained with the help of the new notions of one-sided local moduli and
quasi-moduli of continuity which we discuss more generally for functions with
values in metric spaces.Comment: 26 pages, 1 figur
Muon stopping power and range tables 10 MeV-100 TeV
The mean stopping power for high-energy muons in matter can be described by −dE/dx = a(E) + b(E)E, where a(E) is the electronic stopping power and b(E) is the energy-scaled con-tribution from radiative processes—bremsstrahlung, pair production, and photonuclear interac-tions. a(E) and b(E) are both slowly-varying functions of the muon energy E where radiative effects are important. Tables of these stopping power contributions and continuous-slowing-down-approximation (CSDA) ranges (which neglect multiple scattering and range straggling) are given for a selection of elements, compounds, mixtures, and biological materials for incident kinetic en-ergies in the range 10 MeV to 100 TeV. Tables of the contributions to b(E) are given for the same materials
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