Search results for " magnitude"
showing 10 items of 407 documents
Volatiles in pantellerite magmas: A case study of the Green Tuff Plinian eruption (Island of Pantelleria, Italy)
2013
Abstract The Green Tuff (GT) Plinian eruption, the largest in magnitude at Pantelleria, erupted 3 to 7 km3 DRE of pantellerite magma and a small volume of trachyte. Fifty-nine anorthoclase-hosted melt inclusions from the two basal pumice members were analyzed by FT-IR spectroscopy in order to assess the pre-eruptive H2O content in the pantellerite melt. Microanalytical methods were used to determine major element, Cl, F and S contents. Melt inclusions and glassy groundmasses have a nearly homogeneous pantelleritic composition (peralkaline index = 1.9-2.2) and variable water contents ranging from 1.4 to as high as 4.2 wt %, i.e. much higher than the 1.4 wt % of earlier published studies. The…
μ-e conversion in nuclei versus μ→e γ: an effective field theory point of view
1998
Using an effective lagrangian description we analyze possible new physics contributions to the most relevant muon number violating processes: $\mu \to e \gamma$ and $\mu$--$e$ conversion in nuclei. We identify a general class of models in which those processes are generated at one loop level and in which $\mu$--$e$ conversion is enhanced with respect to $\mu \to e \gamma$ by a large $\ln(m^2_\mu/\Lambda^2),$ where $\Lambda$ is the scale responsible for the new physics. For this wide class of models bounds on $\mu$--$e$ conversion constrain the scale of new physics more stringently than $\mu \to e \gamma$ already at present and, with the expected improvements in $\mu$--$e$ conversion experim…
Conceptual design of the International Axion Observatory (IAXO)
2014
The International Axion Observatory (IAXO) will be a forth generation axion helioscope. As its primary physics goal, IAXO will look for axions or axion-like particles (ALPs) originating in the Sun via the Primakoff conversion of the solar plasma photons. In terms of signal-to-noise ratio, IAXO will be about 4-5 orders of magnitude more sensitive than CAST, currently the most powerful axion helioscope, reaching sensitivity to axion-photon couplings down to a few $\times 10^{-12}$ GeV$^{-1}$ and thus probing a large fraction of the currently unexplored axion and ALP parameter space. IAXO will also be sensitive to solar axions produced by mechanisms mediated by the axion-electron coupling $g_{…
Dissociations and interactions between time, numerosity and space processing
2009
AbstractThis study investigated time, numerosity and space processing in a patient (CB) with a right hemisphere lesion. We tested whether these magnitude dimensions share a common magnitude system or whether they are processed by dimension-specific magnitude systems. Five experimental tasks were used: Tasks 1–3 assessed time and numerosity independently and time and numerosity jointly. Tasks 4 and 5 investigated space processing independently and space and numbers jointly. Patient CB was impaired at estimating time and at discriminating between temporal intervals, his errors being underestimations. In contrast, his ability to process numbers and space was normal. A unidirectional interactio…
High-Resolution Stimulated Raman Spectroscopy of Methane 13CD4 in the Pentad Region
1988
Abstract We present the first Raman spectrum of 13CD4 recorded at room temperature in the pentad region by inverse Raman spectroscopy, thus including the ν1 (A1), 2ν2 (A1), 2ν4 (A1), and ν2 + ν4(F1 + F2) Q branches. It is noteworthy that the overtone bands 2ν2 and 2ν4 are observed for the first time in a methane-like molecule by a coherent Raman process. The wide frequency range investigated, covering 45 cm−1 in three parts, contains more than 300 lines with uncertainty less than 10−3 cm−1 in most cases. These Raman data are combined with high-resolution infrared data in a weighted least-squares fit of the vibration-rotation constants of the pentad, thanks to a relevant partially reduced ef…
Millisecond radiative recombination in poly(phenylene vinylene)-based light-emitting diodes from transient electroluminescence
2007
The current and electroluminescence transient responses of standard poly phenylene vinylene -based light-emitting devices have been investigated. The electroluminescence time response is longer milliseconds scale than the current switch-off time by more than one order of magnitude, in the case of small area devices 0.1 cm2 . For large area devices 6 cm2 the electroluminescence decay time decreases from 1.45 ms to 100 s with increasing bias voltage. The fast current decay limits the electroluminescence decay at higher voltages. Several approaches are discussed to interpret the observed slow decrease of electroluminescence after turning off the bias. One relies upon the Langevin-type bimolecu…
A local chemical potential approach within the variable charge method formalism
2008
A new and computationally efficient implementation of the variable charge method of Streitz and Mintmire (1994 Phys. Rev. B 50 11996) is presented. In particular a local chemical potential approach that optimizes the charge on only those atoms expected to be ionic is developed. By doing so, the charge fluctuation problem experienced in regions far from any oxygen is solved, leading to a linear minimization problem of the electrostatic energy. In the dilute oxygen limit, such an approach can lead to at least an order of magnitude saving in computation.
Spin switching in electronic devices based on 2D assemblies of spin-crossover nanoparticles
2015
In this communication we study the transport properties of two-dimensional assemblies of [Fe(Htrz)2(trz)](BF4) spin-crossover nanoparticles (NPs) with two different morphologies. The NPs have been synthesized made in a similar manner than in our previous study in which single NPs were measured. We prepared free-standing self-assembled monolayer sheets of both SCO NPs formed at the air/liquid interface on holey carbon TEM grids to extract their global arrangement and NP size distributions by STEM-HAADF technique. The SCO NP systems present a rod-like shape and possess two different volumes, corresponding to lengths of 25 nm and 44 nm along the rod direction and average diameters of 10 nm and…
Reduction of low-frequency 1/f noise in Al-AlOx-Al tunnel junctions by thermal annealing
2010
We report that annealing Al-AlOx-Al tunnel junctions in a vacuum chamber at temperature of 400C reduces the characteristic 1/f noise in the junctions, in some cases by an order of magnitude. Both ultra high vacuum and high vacuum fabricated samples demonstrated a significant reduction in the 1/f noise level. Temperature dependence of the noise was studied between 4.2 and 340 Kelvin, with a linear dependence below 100 K, but a faster increase above. The results are consistent with a model where the density of charge trapping two level-systems within the tunneling barrier is reduced by the annealing process.
Orbital Rashba effect in a surface-oxidized Cu film
2020
Recent experimental observation of an unexpectedly large current-induced spin-orbit torque in surface oxidized Cu on top of a ferromagnet pointed to a possibly prominent role of the orbital Rashba effect (ORE) in this system. Here, we use first principles methods to investigate the ORE in a system of oxygen monolayer deposited on top of a Cu(111) film. We show that surface oxidization of the Cu film leads to a gigantic enhancement of the ORE near the Fermi energy. The resulting chiral orbital texture in the momentum space is exceptionally strong, reaching as much as $\ensuremath{\sim}0.5\ensuremath{\hbar}$ in magnitude. We find that resonant hybridization between O $p$ states and Cu $d$ sta…