1,365 research outputs found
Dynamical frictional phenomena in an incommensurate two-chain model
Dynamical frictional phenomena are studied theoretically in a two-chain model
with incommensurate structure. A perturbation theory with respect to the
interchain interaction reveals the contributions from phonons excited in each
chain to the kinetic frictional force. The validity of the theory is verified
in the case of weak interaction by comparing with numerical simulation. The
velocity and the interchain interaction dependences of the lattice structure
are also investigated. It is shown that peculiar breaking of analyticity states
appear, which is characteristic to the two-chain model. The range of the
parameters in which the two-chain model is reduced to the Frenkel-Kontorova
model is also discussed.Comment: RevTex, 9 pages, 7 PostScript figures, to appear in Phys. Rev.
Friction, order, and transverse pinning of a two-dimensional elastic lattice under periodic and impurity potentials
Frictional phenomena of two-dimensional elastic lattices are studied
numerically based on a two-dimensional Frenkel-Kontorova model with impurities.
It is shown that impurities can assist the depinning. We also investigate
anisotropic ordering and transverse pinning effects of sliding lattices, which
are characteristic of the moving Bragg glass state and/or transverse glass
state. Peculiar velocity dependence of the transverse pinning is observed in
the presence of both periodic and random potentials and discussed in the
relation with growing order and discommensurate structures.Comment: RevTeX, 4 pages, 5 figures. to appear in Phys. Rev. B Rapid Commu
Effect of Local Inhomogeneity on Nucleation; Case of Charge Density Wave Depinning
The spatial inhomogeneities are expected to affect nucleation process in an
essential way. These effects are studied theoretically by considering the case
of the depinning of the charge density wave as a typical example. The threshold
field of the depinning of the one-dimensional commensurate charge density wave
with one impurity has been examined classically based on the phase Hamiltonian
at absolute zero. It is found that the threshold field is lowered by a finite
amount compared to that in the absence of an impurity.Comment: pages 12, LaTeX, 9 figures, uses jpsj.sty, submitted to J. Phys. Soc.
Jp
Microstructural Change and Mechanical Property of Neutron Irradiated Ti-Ni Shape Memory Alloy
Microstructural change and mechanical property of Ti-Ni shape memory alloy after neutron irradiation have been studied. The neutron doses were from 1.4×10^ to 1.2×10^n/cm^2, and the irradiation temperature was under 423K. A halo ring was observed after the irradiation of 1.2×10^n/cm^2, which means that amorphous phase was induced by the neutron irradiation. In stress-strain curve, the critical point (σ_M) increased as the dose increased. At the highest dose, the stress-strain curve lost pseudoelasticity. These results indicate that such mechanical properties strongly depend on the amorphous formation
Resistive relaxation in field-induced insulator-metal transition of a (LaPr)SrMnO bilayer manganite single crystal
We have investigated the resistive relaxation of a
(LaPr)SrMnO single crystal, in
order to examine the slow dynamics of the field-induced insulator to metal
transition of bilayered manganites. The temporal profiles observed in remanent
resistance follow a stretched exponential function accompanied by a slow
relaxation similar to that obtained in magnetization and magnetostriction data.
We demonstrate that the remanent relaxation in magnetotransport has a close
relationship with magnetic relaxation that can be understood in the framework
of an effective medium approximation by assuming that the first order parameter
is proportional to the second order one.Comment: 6 pages,5 figure
Stretched exponential behavior in remanent lattice striction of a (La,Pr)SrMnO bilayer manganite single crystal
We have investigated the time dependence of remanent magnetostriction in a
(La,Pr)SrMnO single crystal, in order to examine
the slow dynamics of lattice distortion in bilayered manganites. A competition
between double exchange and Jahn-Teller type orbital-lattice interactions
results in the observed lattice profile following a stretched exponential
function. This finding suggests that spatial growth of the local lattice
distortions coupled with e-electron orbital strongly correlates with the
appearance of the field-induced CMR effect.Comment: 3 figure
The human fear-circuitry and fear-induced fainting in healthy individuals The paleolithic-threat hypothesis
The Paleolithic-Threat
hypothesis reviewed here posits
that habitual efferent fainting can
be traced back to fear-induced
allelic polymorphisms that were
selected into some genomes of
anatomically, mitochondrially, and
neurally modern humans (Homo
sapiens sapiens) in the Mid-Paleolithic because of the survival
advantage they conferred during
periods of inescapable threat. We
posit that during Mid-Paleolithic
warfare an encounter with “a
stranger holding a sharp object”
was consistently associated with
threat to life. A heritable hard-
wired or firm-wired (prepotentiated) predisposition to abruptly
increase vagal tone and collapse
flaccidly rather than freeze or
attempt to flee or fight in response
to an approaching sharp object, a
minor injury, or the sight of blood,
polymorphism for the hemodynamically “paradoxical” flaccid-
immobility in response to these
stimuli may have increased some
non-combatants’ chances of survival. This is consistent with the
unusual age and sex pattern of
fear-induced fainting. The Paleolithic-Threat hypothesis also predicts a link to various hypo-androgenic states (e.g. low dehydroxyepiandrosterone-sulfate. We offer
five predictions testable via epidemiological, clinical, and ethological/primatological methods. The
Paleolithic-Threat hypothesis has
implications for research in the
aftermath of man-made disasters,
such as terrorism against civilians,
a traumatic event in which this
hypothesis predicts epidemics of
fear-induced faintin
Microvascular Architecture of the Filiform Papillae in Primates and Insectivores
The microvascular architecture of filiform papillae was investigated under a scanning electron microscope in man, Japanese monkeys, common squirrel monkeys, common marmosets, common tree shrews, large Japanese moles and dwarf shrews utilizing microvascular corrosion casts. Filiform papillae were circularly arranged in primates, and each of them was supplied by a hairpin capillary loop. These papillae sometimes were aggregated. The filiform papillae of Japanese monkeys exhibited markedly locational differences on the lingual dorsum and were supplied by circularly arranged capillary loops or by an intrapapillary capillary network. Small filiform papillae were located on an epithelial eminence in the lingual radix, each of them supplied by a low and simple hairpin capillary loop. The aggregated filiform papillae of common squirrel monkeys were less frequent without any locational differences. Low filiform papillae of common marmosets and tree shrews were simpler in form, being arranged in a circle and supplied by a simple hairpin capillary loop. The filiform papillae of insectivores were not arranged in a circle. The filiform papillae of dwarf shrews were supplied by an incomplete capillary ring without a loop. With respect to species differences, the circularly arranged capillary loops in man were most complicated and highly developed. Microvascular architecture of the filiform papillae of insectivores was much simpler, different from those observed in primates
Re-Conceptualizing the Foundation Is Course
This paper described the new realities regarding information systems and the current management practices of contemporary information system that impact pedagogy. A possible solution to the current gap in enrollments and disconnect with industry is introduced and explained. In sum, the authors offer a novel method for the introductory Information Systems course. This approach addresses each of the IS 2010 learning outcomes while also giving students practical hands on experience with cloud-based enterprise class software. This course has potential to increase the realism and applied nature within an introductory course. The learning outcomes and the “flipped classroom” approach is explained in detail
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