183 research outputs found
Software selection based on analysis and forecasting methods, practised in 1C
The research focuses on the problem of a "1C: Enterprise 8" platform inboard mechanisms for data analysis and forecasting. It is important to evaluate and select proper software to develop effective strategies for customer relationship management in terms of sales, as well as implementation and further maintenance of software. Research data allows creating new forecast models to schedule further software distribution
Surface acoustic wave modulation of single photon emission from GaN/InGaN nanowire quantum dots
On-chip quantum information processing requires controllable quantum light
sources that can be operated on-demand at high-speeds and with the possibility
of in-situ control of the photon emission wavelength and its optical
polarization properties. Here, we report on the dynamic control of the optical
emission from core-shell GaN/InGaN nanowire (NW) heterostructures using radio
frequency surface acoustic waves (SAWs). The SAWs are excited on the surface of
a piezoelectric lithium niobate crystal equipped with a SAW delay line onto
which the NWs were mechanically transferred. Luminescent quantum dot (QD)-like
exciton localization centers induced by compositional fluctuations within the
InGaN nanoshell were identified using stroboscopic micro-photoluminescence
(micro-PL) spectroscopy. They exhibit narrow and almost fully linearly
polarized emission lines in the micro-PL spectra and a pronounced anti-bunching
signature of single photon emission in the photon correlation experiments. When
the nanowire is perturbed by the propagating SAW, the embedded QD is
periodically strained and its excitonic transitions are modulated by the
acousto-mechanical coupling, giving rise to a spectral fine-tuning within a
~1.5 meV bandwidth at the acoustic frequency of ~330 MHz. This outcome can be
further combined with spectral detection filtering for temporal control of the
emitted photons. The effect of the SAW piezoelectric field on the QD charge
population and on the optical polarization degree is also observed. The
advantage of the acousto-optoelectric over other control schemes is that it
allows in-situ manipulation of the optical emission properties over a wide
frequency range (up to GHz frequencies).Comment: arXiv admin note: text overlap with arXiv:1902.0791
Angular distributions of secondary electrons in fast particle-atom scattering
We present the angular distribution of electrons knocked out from an atom in
a fast charge particle collision at small momentum transfer. It is determined
not only by dipole but also by quadrupole transitions, the contribution of
which can be considerably enhanced as compared to the case of photoionization.
There the non-dipole parameters are suppressed as compared to the dipole ones
by the parameter \omega R/c << 1, where is the photon energy, R is the ionized
shell radius and c is the speed of light. This suppression in fast
electron-atom collisions can be considerably reduced: the corresponding
expansion parameter \omega R/ \nu << 1 is much bigger than in photoionization,
since the speed of the incoming electron is much smaller than c. In formation
of the angular distribution it is decisively important that the ionizing field
in collision process is longitudinal, while in photoionization - it is
transversal.
We illustrate the general formulas by concrete results for outer s-, p-, and
some nd-subshells of multi-electron noble gas atoms Ar, Kr and Xe, at several
transferred momentum values: q=0.0, 0.1, 1.1, 2.1. Even for very small
transferred momentum q, i.e. in the so-called optical limit, the deviations
from the photoionization case are prominent.Comment: arXiv admin note: substantial text overlap with arXiv:1012.5465 and
arXiv:1108.101
Under the influence of new educational technologies: the theory of electrolytic dissociation
The article describes a computer programs for study of the chemistry section, training calculations and knowledge testΠ Π°ΡΡΠΌΠΎΡΡΠ΅Π½Ρ ΠΊΠΎΠΌΠΏΡΡΡΠ΅ΡΠ½ΡΠ΅ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΡ Π΄Π»Ρ ΠΈΠ·ΡΡΠ΅Π½ΠΈΡ ΡΡΡΠ΄Π΅Π½ΡΠ°ΠΌΠΈ Ρ
ΠΈΠΌΠΈΠΈ, Π²ΡΠΏΠΎΠ»Π½Π΅Π½ΠΈΡ ΠΈΠΌΠΈ ΠΏΡΠ°ΠΊΡΠΈΡΠ΅ΡΠΊΠΈΡ
Π·Π°Π΄Π°Π½ΠΈΠΉ ΠΈ ΠΏΡΠΎΠ²Π΅ΡΠΊΠΈ Π·Π½Π°Π½ΠΈ
Photoionization of atoms stuffed inside a two-shell fullerene
The photoionization of a two-shell endohedral A@CN1@CN2 is considered.
Formulas are presented for cross-sections and angular anisotropy parameters,
both dipole and non-dipole. The effect of the fullerenes shell upon
photoelectron from atom A is taken into account substituting the action of the
fullerene by two zero-thickness "bubble potential". The fullerenes shells
polarization is included assuming that the radius of the outer shell R2 is much
bigger than the inner R1 and both much exceeds the atomic radius r. This
permits to express the effect via CN1,N2 polarizabilities, which are connected
to their photoionization cross-sections. The interaction between shells CN1 and
CN2 is taken into account in the Random Phase Approximation (RPA). The effect
of photoelectron scattering by both "bubble potentials" is included in the
lowest order and in the RPA frame. As concrete examples, two endohedrals
Ar@C60@C240 and Xe@C60@C240 are considered. In the first case we consider 3p
and 3s, while in the second 5p, 5s and 4d subshells. A whole variety of new
peculiarities are found that deserve experimental verification
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