8,879 research outputs found
Visual Affect Around the World: A Large-scale Multilingual Visual Sentiment Ontology
Every culture and language is unique. Our work expressly focuses on the
uniqueness of culture and language in relation to human affect, specifically
sentiment and emotion semantics, and how they manifest in social multimedia. We
develop sets of sentiment- and emotion-polarized visual concepts by adapting
semantic structures called adjective-noun pairs, originally introduced by Borth
et al. (2013), but in a multilingual context. We propose a new
language-dependent method for automatic discovery of these adjective-noun
constructs. We show how this pipeline can be applied on a social multimedia
platform for the creation of a large-scale multilingual visual sentiment
concept ontology (MVSO). Unlike the flat structure in Borth et al. (2013), our
unified ontology is organized hierarchically by multilingual clusters of
visually detectable nouns and subclusters of emotionally biased versions of
these nouns. In addition, we present an image-based prediction task to show how
generalizable language-specific models are in a multilingual context. A new,
publicly available dataset of >15.6K sentiment-biased visual concepts across 12
languages with language-specific detector banks, >7.36M images and their
metadata is also released.Comment: 11 pages, to appear at ACM MM'1
NMR studies of Successive Phase Transitions in Na0.5CoO2 and K0.5CoO2
59Co- and 23Na-NMR measurements have been carried out on polycrystalline and
c-axis aligned samples of Na0.5CoO2, which exhibits successive transitions at
temperatures T = 87 K (= Tc1) and T = 53 K (= Tc2). 59Co-NMR has also been
carried out on c-axis aligned crystallites of K0.5CoO2 with similar successive
transitions at Tc1 ~ 60 K and Tc2 ~ 20 K. For Na0.5CoO2, two sets of three NMR
lines of 23Na nuclei explained by considering the quadrupolar frequencies nuQ
~1.32 and 1.40 MHz have been observed above Tc1, as is expected from the
crystalline structure. Rather complicated but characteristic variation of the
23Na-NMR spectra has been observed with varying T through the transition
temperatures, and the internal fields at two crystallographically distinct Na
sites are discussed on the basis of the magnetic structures reported
previously. The internal fields at two distinct Co sites observed below Tc1 and
the 591/T1-T curves of Na0.5CoO2 and K0.5CoO2 are also discussed in a
comparative way.Comment: 7 pages, 10 figures, submitted to J. Phys. Soc. Jpn, correction is
made in right colum of p6 (35th line) as K0.5CoO2-->Na0.5CoO
Imaging Quasiparticle Interference in Bi2Sr2CaCu2O8+d
Scanning tunneling spectroscopy of the high-Tc superconductor Bi2Sr2CaCu2O8+d
reveals weak, incommensurate, spatial modulations in the tunneling conductance.
Images of these energy-dependent modulations are Fourier analyzed to yield the
dispersion of their wavevectors. Comparison of the dispersions with
photoemission spectroscopy data indicates that quasiparticle interference, due
to elastic scattering between characteristic regions of momentum-space,
provides a consistent explanation for the conductance modulations, without
appeal to another order parameter. These results refocus attention on
quasiparticle scattering processes as potential explanations for other
incommensurate phenomena in the cuprates. The momentum-resolved tunneling
spectroscopy demonstrated here also provides a new technique with which to
study quasiparticles in correlated materials.Comment: 10 pages text, 4 pages figure
Excitation Spectrum of the Holstein Model
In this paper the polaron problem for the Holstein model is studied in the
weak coupling limit. We use second order perturbation theory to construct
renormalized electron and phonons. Eigenstates of the Hamiltonian are labelled
and the excitation spectrum is constructed.Comment: 4 pages, revtex, 1 figures, more stuff at
http://www.mpipks-dresden.mpg.de/~robin/robin.htm
Impurity Effect on the In-plane Penetration Depth of the Organic Superconductors -(BEDT-TTF) ( = Cu(NCS) and Cu[N(CN)]Br)
We report the in-plane penetration depth of single
crystals -(BEDT-TTF) ( Cu(NCS) and Cu[N(CN)]Br) by
means of the reversible magnetization measurements under the control of
cooling-rate. In = Cu(NCS), as an
extrapolation toward = 0 K does not change by the cooling-rate within the
experimental accuracy, while is slightly reduced. On the other
hand, in = Cu[N(CN)]Br, indicates a distinct
increase by cooling faster. The different behavior of
on cooling-rate between the two salts is quantitatively explained in terms of
the local-clean approximation (London model), considering that the former salt
belongs to the very clean system and the later the moderate clean one. The good
agreement with this model demonstrates that disorders of ethylene-group in
BEDT-TTF introduced by cooling faster increase the
electron(quasiparticle)-scattering, resulting in shorter mean free path.Comment: 8 pages, 9 figure
Size Dependence of Metal-Insulator Transition in Stoichiometric Fe3O4 Nanocrystals
Magnetite (Fe3O4) is one of the most actively studied materials with a famous
metal-insulator transition (MIT), so-called the Verwey transition at around 123
K. Despite the recent progress in synthesis and characterization of Fe3O4
nanocrystals (NCs), it is still an open question how the Verwey transition
changes on a nanometer scale. We herein report the systematic studies on size
dependence of the Verwey transition of stoichiometric Fe3O4 NCs. We have
successfully synthesized stoichiometric and uniform-sized Fe3O4 NCs with sizes
ranging from 5 to 100 nm. These stoichiometric Fe3O4 NCs show the Verwey
transition when they are characterized by conductance, magnetization, cryo-XRD,
and heat capacity measurements. The Verwey transition is weakly size-dependent
and becomes suppressed in NCs smaller than 20 nm before disappearing completely
for less than 6 nm, which is a clear, yet highly interesting indication of a
size effect of this well-known phenomena. Our current work will shed new light
on this ages-old problem of Verwey transition.Comment: 18 pages, 4 figures, Nano Letters (accepted
The Wiimote on the Playground Phys. Teach. 51, 272 (2013) Helicopter Toy and Lift Estimation Phys. Teach
The detailed design of a robust and inexpensive optical trap system is presented. The system features high-sensitivity back focal plane position detection, mechanically controlled specimen stage movement, and fluorescence imaging to provide broad experimental applications. Three educational experimental modules are described to cover basic concepts in optical trapping and biophysics at a level appropriate for undergraduate students
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