12,360 research outputs found
Magnetic remanence of Josephson junction arrays
In this work we study the magnetic remanence exhibited by Josephson junction
arrays in response to an excitation with an AC magnetic field. The effect,
predicted by numerical simulations to occur in a range of temperatures, is
clearly seen in our tridimensional disordered arrays. We also discuss the
influence of the critical current distribution on the temperature interval
within which the array develops a magnetic remanence. This effect can be used
to determine the critical current distribution of an array.Comment: 8 pages, 4 figures, Talk to be presented on 44th Annual Conference on
Magnetism & Magnetic Materials, San Jose, CA, USA Accepted to be published in
Journal of Applied Physic
Irreversibility line and low-field grain-boundary pinning in electron-doped superconducting thin films
AC magnetic susceptibilities of electron-doped Pr_{1.85}Ce_{0.15}CuO_4 (PCCO)
and Sm_{1.85}Ce_{0.15}CuO_4 (SCCO) granular thin films have been measured as a
function of temperature and magnetic-field strength. Depending on the level of
homogeneity of our films, two different types of the irreversibility line (IL)
defined as the intergrain-loss peak temperature in the imaginary part of
susceptibility have been found. The obtained results are described via the
critical-state model taking into account the low-field grain-boundary pinning.
The extracted pinning-force densities in more granular SCCO films turn out to
be four times larger than their counterparts in less granular PCCO films
Universal R-C crossover in current-voltage characteristics for unshunted array of overdamped Nb-AlO_x-Nb Josephson junctions
We report on some unusual behavior of the measured current-voltage
characteristics (CVC) in artificially prepared two-dimensional unshunted array
of overdamped Nb-AlO_x-Nb Josephson junctions. The obtained nonlinear CVC are
found to exhibit a pronounced (and practically temperature independent)
crossover at some current I_{cr}=\left(\frac{1}{2\beta_C}-1\right)I_C from a
resistance R dominated state with V_R=R\sqrt{I^2-I_C^2} below I_{cr} to a
capacitance C dominated state with V_C=\sqrt{\frac{\hbar}{4eC}} \sqrt{I-I_C}
above I_{cr}. The origin of the observed behavior is discussed within a
single-plaquette approximation assuming the conventional RSJ model with a
finite capacitance and the Ambegaokar-Baratoff relation for the critical
current of the single junction
Manifestation of geometric resonance in current dependence of AC susceptibility for unshunted array of Nb-AlOx-Nb Josephson junctions
A pronounced resonance-like structure has been observed in the current
dependence of AC susceptibility for two-dimensional array of unshunted
Nb-AlOx-Nb Josephson junctions. Using a single-plaquette approximation, we were
able to successfully fit our data assuming that resonance structure is related
to the geometric (inductive) properties of the array.Comment: to appear in Physica C (in press
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Is social decision making for close others consistent across domains and within individuals?
Humans make decisions across a variety of social contexts. Though social decision-making research has blossomed in recent decades, surprisingly little is known about whether social decision-making preferences are consistent across different domains. We conducted an exploratory study in which participants made choices about 2 types of close others: parents and friends. To elicit decision making preferences, we pit the interests in parents and friends against one another. To assess the consistency of preferences for close others, decision making was assessed in three domains-risk taking, probabilistic learning, and self-other similarity judgments. We reasoned that if social decision-making preferences are consistent across domains, participants ought to exhibit the same preference in all three domains (i.e., a parent preference, based on prior work), and individual differences in preference magnitude ought to be conserved across domains within individuals. A combination of computational modeling, random coefficient regression, and traditional statistical tests revealed a robust parent-over-friend preference in the risk taking and probabilistic learning domains but not the self-other similarity domain. Preferences for parent-over-friend in the risk-taking domain were strongly associated with similar preferences in the probabilistic learning domain but not the self-other similarity domain. These results suggest that distinct and dissociable value-based and social-cognitive computations underlie social decision making. (PsycInfo Database Record (c) 2020 APA, all rights reserved)
Fungos associados a podridão penduncular em mangueira irrigada no submedio São Francisco e eficiencia de fungicidas in vitro e in vivo.
Fungos associados à podridão peduncular foram identificados e a eficiência de fungicidas foi avaliada
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