24,478 research outputs found
Analysis of the trajectory, loads and heating experienced by a body passing through a supersonic flow field
Analytical methods for determination of trajectories, loads, and heating experienced by spacecraft passing through rocket exhaust fiel
Large magnetoresistance in bcc Co/MgO/Co and FeCo/MgO/FeCo tunneling junctions
By use of first-principles electronic structure calculations, we predict that
the magnetoresistance of the bcc Co(100)/MgO(100)/bcc Co(100) and
FeCo(100)/MgO(100)/FeCo(100) tunneling junctions can be several times larger
than the very large magnetoresistance predicted for the
Fe(100)/MgO(100)/Fe(100) system. The origin of this large magnetoresistance can
be understood using simple physical arguments by considering the electrons at
the Fermi energy travelling perpendicular to the interfaces. For the minority
spins there is no state with symmetry whereas for the majority spins
there is only a state. The state decays much more slowly
than the other states within the MgO barrier. In the absence of scattering
which breaks the conservation of momentum parallel to the interfaces, the
electrons travelling perpendicular to the interfaces undergo total reflection
if the moments of the electrodes are anti-parallel. These arguments apply
equally well to systems with other well ordered tunnel barriers and for which
the most slowly decaying complex energy band in the barrier has
symmetry. Examples include systems with (100) layers constructed from Fe, bcc
Co, or bcc FeCo electrodes and Ge, GaAs, or ZnSe barriers.Comment: 8 figure files in eps forma
Perceptual bias, more than age, impacts on eye movements during face processing
Consistent with the right hemispheric dominance for face processing, a left perceptual bias (LPB) is typically demonstrated by younger adults viewing faces and a left eye movement bias has also been revealed. Hemispheric asymmetry is predicted to reduce with age and older adults have demonstrated a weaker LPB, particularly when viewing time is restricted. What is currently unclear is whether age also weakens the left eye movement bias. Additionally, a right perceptual bias (RPB) for facial judgments has less frequently been demonstrated, but whether this is accompanied by a right eye movement bias has not been investigated. To address these issues older and younger adultsâ eye movements and gender judgments of chimeric faces were recorded in two time conditions. Age did not significantly weaken the LPB or eye movement bias; both groups looked initially to the left side of the face and made more fixations when the gender judgment was based on the left side. A positive association was found between LPB and initial saccades in the freeview condition and with all eye movements (initial saccades, number and duration of fixations) when time was restricted. The accompanying eye movement bias revealed by LPB participants contrasted with RPB participants who demonstrated no eye movement bias in either time condition. Consequently, increased age is not clearly associated with weakened perceptual and eye movement biases. Instead an eye movement bias accompanies an LPB (particularly under restricted viewing time conditions) but not an RPB
Aerobrake assembly with minimum Space Station accommodation
The minimum Space Station Freedom accommodations required for initial assembly, repair, and refurbishment of the Lunar aerobrake were investigated. Baseline Space Station Freedom support services were assumed, as well as reasonable earth-to-orbit possibilities. A set of three aerobrake configurations representative of the major themes in aerobraking were developed. Structural assembly concepts, along with on-orbit assembly and refurbishment scenarios were created. The scenarios were exercised to identify required Space Station Freedom accommodations. Finally, important areas for follow-on study were also identified
Tracking sand-fairways through a deformed turbidite system : the Numidian (Miocene) of Central Sicily, Italy
The research presented here is funded by BG Group in partnership with CNPq-Brazil (National Council for Scientific and Technological Development). Rosanna Maniscalco acknowledges a FIR 2014 grant awarded from the University of Catania. We thank Christian Haug Eide, David Hodgson and Enrico Tavarnelli for constructive and thorough reviews on an earlier draft that have greatly improved this contribution.Peer reviewedPublisher PD
Syn-kinematic sedimentary systems as constraints on the structural response of thrust belts : re-examining the structural style of the Maghrebian thrust belt of Eastern Sicily
We are indebted to the generosity of the late Fabio Lentini. While he may not have agreed with our findings, he nevertheless openly and cheerfully shared his mapping and insight of Sicilian geology. This work also builds upon many yearsâ collaboration between us, initiated by the late Mario Grasso (the Pantagruelian Master of Speranza et alii, 2018). The mapping of Lentini, Grasso and colleagues represents a remarkable resource for future geologists. We dedicate this contribution to their memory. We thank Sveva Corrado and an anonymous referee for constructive comments on an earlier draft of this paper. Butlerâs Sicilian field research has been variously funded by the UKâs Natural Environment Research Council and the Royal Society. Maniscalco acknowledges âFondi per la Ricerca di AteneoPiano per la Ricerca 2016/2018â. Pinter was supported through a PhD grant funded by the BG Group (now Shell) and Brazilâs National Council for Scientific and Technological Development (CNPq).Peer reviewedPublisher PD
Splitting The Gluon?
In the strongly correlated environment of high-temperature cuprate
superconductors, the spin and charge degrees of freedom of an electron seem to
separate from each other. A similar phenomenon may be present in the strong
coupling phase of Yang-Mills theories, where a separation between the color
charge and the spin of a gluon could play a role in a mass gap formation. Here
we study the phase structure of a decomposed SU(2) Yang-Mills theory in a mean
field approximation, by inspecting quantum fluctuations in the condensate which
is formed by the color charge component of the gluon field. Our results suggest
that the decomposed theory has an involved phase structure. In particular,
there appears to be a phase which is quite reminiscent of the superconducting
phase in cuprates. We also find evidence that this phase is separated from the
asymptotically free theory by an intermediate pseudogap phase.Comment: Improved discussion of magnetic nature of phases; removed
unsubstantiated speculation about color confinemen
Calculating the output distribution of stack filters that are erosion-dilation cascades, in particular LULU-filters
Original article available at http://arxiv.org/ENGLISH ABSTRACT: Two procedures to compute the output distribution 0S of certain stack filters S (so
called erosion-dilation cascades) are given. One rests on the disjunctive normal form of S
and also yields the rank selection probabilities. The other is based on inclusion-exclusion
and e.g. yields 0S for some important LULU-operators S. Properties of 0S can be used to
characterize smoothing properties.Preprin
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