817 research outputs found
TEACHING IN THE CLOUD MICROELECTRONICS UBIQUITOUS LAB (MULAB)
CAD laboratory students activity is mandatory for microelectronics teaching. This, applied in the deep-submicron era, creates new challenges to couple software management simplicity to user friendliness inside lab sessions, which requires the use of complex tools and concepts. In this paper, a new approach to microelectronics CAD deployment is presented, based on virtualization capabilities of new servers hardware and software technology. A test case, realized at Politecnico di Torino, degree of Electronic Engineering, is presented, with real world results on resource consumption and user satisfactio
Particle Acceleration in Mildly Relativistic Shearing Flows: the Interplay of Systematic and Stochastic Effects, and the Origin of the Extended High-energy Emission in AGN Jets
The origin of the extended X-ray emission in the large-scale jets of active
galactic nuclei (AGNs) poses challenges to conventional models of acceleration
and emission. Although the electron synchrotron radiation is considered the
most feasible radiation mechanism, the formation of the continuous large-scale
X-ray structure remains an open issue. As astrophysical jets are expected to
exhibit some turbulence and shearing motion, we here investigate the potential
of shearing flows to facilitate an extended acceleration of particles and
evaluate its impact on the resultant particle distribution. Our treatment
incorporates systematic shear and stochastic second-order Fermi effects. We
show that for typical parameters applicable to large-scale AGN jets, stochastic
second-order Fermi acceleration, which always accompanies shear particle
acceleration, can play an important role in facilitating the whole process of
particle energization. We study the time-dependent evolution of the resultant
particle distribution in the presence of second-order Fermi acceleration, shear
acceleration, and synchrotron losses using a simple Fokker--Planck approach and
provide illustrations for the possible emergence of a complex (multicomponent)
particle energy distribution with different spectral branches. We present
examples for typical parameters applicable to large-scale AGN jets, indicating
the relevance of the underlying processes for understanding the extended X-ray
emission and the origin of ultrahigh-energy cosmic rays.Comment: 26 pages, 8 figures; to appear in Ap
Systematic analysis of SNR in bipartite Ghost Imaging with classical and quantum light
We present a complete and exhaustive theory of signal-to-noise-ratio in
bipartite ghost imaging with classical (thermal) and quantum (twin beams)
light. The theory is compared with experiment for both twin beams and thermal
light in a certain regime of interest
vrLab: A Virtual and Remote Low Cost Electronics Lab Platform
SARS-CoV2 pandemic stressed the need to increase adoption of remote teaching. Technical courses, specifically electronic engineering ones, suffered the miss of real lab experiments directly carried out by students. In this paper a new approach is presented, based on the usage of very low cost experimental boards, which act both as a measurement instrument and a programmable prototype circuit. A first board, targeted to analog and digital electronics courses experiments, has been designed, and is described in this paper
Spontaneous Octahedral Tilting in the Cubic Inorganic Caesium Halide Perovskites CsSnX and CsPbX (X = F, Cl, Br, I)
The local crystal structures of many perovskite-structured materials deviate
from the average space group symmetry. We demonstrate, from lattice-dynamics
calculations based on quantum chemical force constants, that all the
caesium-lead and caesium-tin halide perovskites exhibit vibrational
instabilities associated with octahedral titling in their high-temperature
cubic phase. Anharmonic double-well potentials are found for zone-boundary
phonon modes in all compounds with barriers ranging from 108 to 512 meV. The
well depth is correlated with the tolerance factor and the chemistry of the
composition, but is not proportional to the imaginary harmonic phonon
frequency. We provide quantitative insights into the thermodynamic driving
forces and distinguish between dynamic and static disorder based on the
potential-energy landscape. A positive band gap deformation (spectral
blueshift) accompanies the structural distortion, with implications for
understanding the performance of these materials in applications areas
including solar cells and light-emitting diodes
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