10,785 research outputs found
Fate of the Peak Effect in a Type-II Superconductor: Multicriticality in the Bragg-Glass Transition
We have used small-angle-neutron-scattering (SANS) and ac magnetic
susceptibility to investigate the global magnetic field H vs temperature T
phase diagram of a single crystal Nb in which a first-order transition of
Bragg-glass melting (disordering), a peak effect, and surface superconductivity
are all observable. It was found that the disappearance of the peak effect is
directly related to a multicritical behavior in the Bragg-glass transition.
Four characteristic phase boundary lines have been identified on the H-T plane:
a first-order line at high fields, a mean-field-like continuous transition line
at low fields, and two continuous transition line associated with the onset of
surface and bulk superconductivity. All four lines are found to meet at a
multicritical point.Comment: 4 figure
TimeMachine: Timeline Generation for Knowledge-Base Entities
We present a method called TIMEMACHINE to generate a timeline of events and
relations for entities in a knowledge base. For example for an actor, such a
timeline should show the most important professional and personal milestones
and relationships such as works, awards, collaborations, and family
relationships. We develop three orthogonal timeline quality criteria that an
ideal timeline should satisfy: (1) it shows events that are relevant to the
entity; (2) it shows events that are temporally diverse, so they distribute
along the time axis, avoiding visual crowding and allowing for easy user
interaction, such as zooming in and out; and (3) it shows events that are
content diverse, so they contain many different types of events (e.g., for an
actor, it should show movies and marriages and awards, not just movies). We
present an algorithm to generate such timelines for a given time period and
screen size, based on submodular optimization and web-co-occurrence statistics
with provable performance guarantees. A series of user studies using Mechanical
Turk shows that all three quality criteria are crucial to produce quality
timelines and that our algorithm significantly outperforms various baseline and
state-of-the-art methods.Comment: To appear at ACM SIGKDD KDD'15. 12pp, 7 fig. With appendix. Demo and
other info available at http://cs.stanford.edu/~althoff/timemachine
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Polyisoprene Captured Sulfur Nanocomposite Materials for High-Areal-Capacity Lithium Sulfur Battery
A polyisoprene-sulfur (PIPS) copolymer and nano sulfur composite material (90 wt % sulfur) is synthesized through inverse vulcanization of PIP polymer with micrometer-sized sulfur particles for high-areal-capacity lithium sulfur batteries. The polycrystalline structure and nanodomain nature of the copolymer are revealed through high-resolution transmission electron microscopy (HRTEM). PIP polymer is also used as binders for the electrode to further capture the dissovlved polysulfides. A high areal capacity of ca. 7.0 mAh/cm2 and stable cycling are achieved based on the PIPS nanosulfur composite with a PIP binder, crucial to commercialization of lithium sulfur batteries. The chemical confinement both at material and electrode level alleviates the diffusion of polysulfides and the shuttle effect. The sulfur electrodes, both fresh and cycled, are analyzed through scanning electron microscopy (SEM). This approach enables scalable material production and high sulfur utilization at the cell level
Design and test results of different aluminum coating layers on the sCMOS sensors for soft X-ray detection
In recent years, tremendous progress has been made on complementary
metal-oxide-semiconductor (CMOS) sensors for applications as X-ray detectors.
To shield the visible light in X-ray detection, a blocking filter of aluminum
is commonly employed. We designed three types of aluminum coating layers, which
are deposited directly on the surface of back-illuminated sCMOS sensors during
fabrication. A commercial 2k * 2k sCMOS sensor is used to realize these
designs. In this work, we report their performance by comparison with that of
an uncoated sCMOS sensor. The optical transmissions at 660 nm and 850 nm are
measured, and the results show that the optical transmission reaches a level of
about 10-9 for the 200 nm aluminum layer and about 10-4 for the 100 nm aluminum
layer. Light leakage is found around the four sides of the sensor. The readout
noise, fixed-pattern noise and energy resolution of these Al-coated sCMOS
sensors do not show significant changes. The dark currents of these Al-coated
sCMOS sensors show a noticeable increase compared with that of the uncoated
sCMOS sensor at room temperatures, while no significant difference is found
when the sCMOS sensors are cooled down to about -15 degree. The aluminum
coatings show no visible crack after the thermal cycle and aging tests. Based
on these results, an aluminum coating of a larger area on larger sCMOS sensors
is proposed for future work.Comment: Accept for publication in JIns
Exploring metastability via the third harmonic measurements in single crystals of - showing anomalous Peak effect
We explore the metastability effects across the order-disorder transition
pertaining to the peak effect phenomenonon in critical current density ()
via the first and the third harmonic ac susceptibility measurements in the
weakly pinned single crystals of -. An analysis of our data
suggests that an imprint of the limiting (spinodal) temperature above which
is path independent can be conveniently located in the third harmonic
data ().Comment: Accepted for publication in Phys. Rev.
The appraisal similarity effect: how social appraisals influence liking
The effects of cognitive appraisals on interpersonal relationships have hardly been studied. Three experiments examined how empathic social appraisal could influence liking. We tested for the appraisal similarity effect in which perceived similarity in appraisals boosts liking. In Experiment 1, perception of appraisal similarity led participants to express liking by disclosing personal contact information. This effect was replicated using a selfreport measure of liking in Experiments 2 and 3. Also, by independently manipulating attitude similarity, the appraisal similarity effect was deactivated under perceived attitude dissimilarity. Likewise, the robust attitude similarity effect was invalidated under perceived appraisal dissimilarity. In Experiment 3, the perception of validated personal beliefs mediated this interactive effect in a moderated mediation scenario, and the appraisal similarity effect
Inflationary universe in loop quantum cosmology
Loop quantum cosmology provides a nice solution of avoiding the big bang
singularity through a big bounce mechanism in the high energy region. In loop
quantum cosmology an inflationary universe is emergent after the big bounce, no
matter what matter component is filled in the universe. A super-inflation phase
without phantom matter will appear in a certain way in the initial stage after
the bounce; then the universe will undergo a normal inflation stage. We discuss
the condition of inflation in detail in this framework. Also, for slow-roll
inflation, we expect the imprint from the effects of the loop quantum cosmology
should be left in the primordial perturbation power spectrum. However, we show
that this imprint is too weak to be observed.Comment: 21 pages, 4 figures; accepted for publication in JCA
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