416 research outputs found
Properties of latent interface-trap buildup in irradiated metal-oxide-semiconductor transistors determined by switched bias isothermal annealing experiments
Isothermal annealing experiments with switched gate bias have been performed to determine the properties of the latent interface-trap buildup during postirradiation annealing of metal-oxide-semiconductor transistors. It has been found that a bias-independent process occurs until the start of the latent interface-trap buildup. During the buildup itself, oxide-trap charge is not permanently neutralized, but is temporarily compensated. (C) 2000 American Institute of Physics. (DOI: 10.1063/1.1336159
Hamiltonian structure for dispersive and dissipative dynamical systems
We develop a Hamiltonian theory of a time dispersive and dissipative
inhomogeneous medium, as described by a linear response equation respecting
causality and power dissipation. The proposed Hamiltonian couples the given
system to auxiliary fields, in the universal form of a so-called canonical heat
bath. After integrating out the heat bath the original dissipative evolution is
exactly reproduced. Furthermore, we show that the dynamics associated to a
minimal Hamiltonian are essentially unique, up to a natural class of
isomorphisms. Using this formalism, we obtain closed form expressions for the
energy density, energy flux, momentum density, and stress tensor involving the
auxiliary fields, from which we derive an approximate, ``Brillouin-type,''
formula for the time averaged energy density and stress tensor associated to an
almost mono-chromatic wave.Comment: 68 pages, 1 figure; introduction revised, typos correcte
Random Dirac operators with time-reversal symmetry
Quasi-one-dimensional stochastic Dirac operators with an odd number of
channels, time reversal symmetry but otherwise efficiently coupled randomness
are shown to have one conducting channel and absolutely continuous spectrum of
multiplicity two. This follows by adapting the criteria of Guivarch-Raugi and
Goldsheid-Margulis to the analysis of random products of matrices in the group
SO, and then a version of Kotani theory for these operators. Absence of
singular spectrum can be shown by adapting an argument of Jaksic-Last if the
potential contains random Dirac peaks with absolutely continuous distribution.Comment: parts of introduction made more precise, corrections as follow-up on
referee report
Effects of a nine-month physical activity intervention on morphological characteristics and motor and cognitive skills of preschool children
(1) Background: Regular physical activity (PA) plays an important role during early childhood physical and psychological development. This study investigates the effects of a 9-month PA intervention on physiological characteristics and motor and cognitive skills in preschool children. (2) Methods: Preschool children (n = 132; age 4 to 7 years) attending regular preschool programs were nonrandomly assigned to PA intervention (n = 66; 60 min sessions twice per week) or a control group (n = 66; no additional organized PA program) for 9 months. Exercise training for the intervention group included various sports games, outdoor activities, martial arts, yoga, and dance. Anthropometry, motor skills (7 tests), and cognitive skills (Raven’s Colored Progressive Matrices and Cognitive Assessment System) were assessed before and after an intervention period in both groups. Data were analyzed using repeated-measures ANOVA. (3) Results: Body weight significantly increased in both groups over time. Compared to the changes observed in the control group, the intervention group significantly increased in chest circumference (p = 0.022). In contrast, the control group demonstrated an increase in waist circumference (p = 0.001), while these measures in the intervention group remained stable. Participants in the intervention group improved running speed (p = 0.016) and standing broad jump (p = 0.000). The flexibility level was maintained in the intervention group, while a significant decrease was observed in the control group (p = 0.010). Children from the intervention group demonstrated progress in the bent-arm hang test (p = 0.001), unlike the control group subjects. Varied improvements in cognitive skills were observed for different variables in both intervention and control groups, with no robust evidence for PA-intervention-related improvements. (4) Conclusions: Preschool children’s participation in a preschool PA intervention improves their motor skills
Labour Market and Social Policy in Italy: Challenges and Changes. Bertelsmann Policy Brief #2016/02
vEight years after the outbreak of the financial crisis, Italy has still to cope with and
overcome a plethora of economic and social challenges. On top of this, it faces an
unfavourable demographic structure and severe disparities between its northern and
southern regions. Some promising reforms have recently been enacted, specifically
targeting poverty and social exclusion. However, much more remains to be done on
the way towards greater economic stability and widely shared prosperity
Normal transport properties for a classical particle coupled to a non-Ohmic bath
We study the Hamiltonian motion of an ensemble of unconfined classical
particles driven by an external field F through a translationally-invariant,
thermal array of monochromatic Einstein oscillators. The system does not
sustain a stationary state, because the oscillators cannot effectively absorb
the energy of high speed particles. We nonetheless show that the system has at
all positive temperatures a well-defined low-field mobility over macroscopic
time scales of order exp(-c/F). The mobility is independent of F at low fields,
and related to the zero-field diffusion constant D through the Einstein
relation. The system therefore exhibits normal transport even though the bath
obviously has a discrete frequency spectrum (it is simply monochromatic) and is
therefore highly non-Ohmic. Such features are usually associated with anomalous
transport properties
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