85 research outputs found
Semantic Object Parsing with Local-Global Long Short-Term Memory
Semantic object parsing is a fundamental task for understanding objects in
detail in computer vision community, where incorporating multi-level contextual
information is critical for achieving such fine-grained pixel-level
recognition. Prior methods often leverage the contextual information through
post-processing predicted confidence maps. In this work, we propose a novel
deep Local-Global Long Short-Term Memory (LG-LSTM) architecture to seamlessly
incorporate short-distance and long-distance spatial dependencies into the
feature learning over all pixel positions. In each LG-LSTM layer, local
guidance from neighboring positions and global guidance from the whole image
are imposed on each position to better exploit complex local and global
contextual information. Individual LSTMs for distinct spatial dimensions are
also utilized to intrinsically capture various spatial layouts of semantic
parts in the images, yielding distinct hidden and memory cells of each position
for each dimension. In our parsing approach, several LG-LSTM layers are stacked
and appended to the intermediate convolutional layers to directly enhance
visual features, allowing network parameters to be learned in an end-to-end
way. The long chains of sequential computation by stacked LG-LSTM layers also
enable each pixel to sense a much larger region for inference benefiting from
the memorization of previous dependencies in all positions along all
dimensions. Comprehensive evaluations on three public datasets well demonstrate
the significant superiority of our LG-LSTM over other state-of-the-art methods.Comment: 10 page
Type-I superconductivity in AlRe
While the pure elements tend to exhibit Type-I rather than Type-II
superconductivity, nearly all compound superconductors are Type-II, with only a
few known exceptions. We report single crystal growth and physical
characterization of the rhenium aluminide AlRe, which we conclude is a
Type-I superconductor based on magnetization, ac-susceptibility, and
specific-heat measurements. This detection of superconductivity, despite the
strong similarity of AlRe to a family of W and Mo aluminides that do not
superconduct, suggests that these aluminides are an ideal testbed for
identifying the relative importance of valence electron count and inversion
symmetry in determining whether a material will superconduct.Comment: 9 pages, 7 figures, CIF file as ancillar
Surface structure and multigap superconductivity of V3Si (111) revealed by scanning tunneling microscopy
V3Si, a classical silicide superconductor with relatively high TC (~16 K), is
promising for constructing silicon-based superconducting devices and
hetero-structures. However, real space characterization on its surfaces and
superconducting properties are still limited. Here we report the first
low-temperature scanning tunnelling microscopy (STM) study on cleaned V3Si
(111) single crystal surface. We observed a r3 by r3 superstructure which
displays mirror symmetry between adjacent terraces, indicating the surface is
V-terminated and reconstructed. The tunneling spectrum shows full
superconducting gap with double pairs of coherence peaks, but has a relatively
small gap size with comparing to bulk TC. Impurity induced in-gap state is
absent on surface defects but present on introduced magnetic adatoms. Upon
applying magnetic field, a hexagonal vortex lattice is visualized.
Interestingly, the vortex size is found to be field dependent, and the
coherence length measured from single vortex at low field is significantly
larger than estimated value from bulk H_c2. These results reflect V3Si is a
multi-band, s- wave superconductor
Knot undulator to generate linearly polarized photons with low on-axis power density
Heat load on beamline optics is a serious problem to generate pure linearly
polarized photons in the third generation synchrotron radiation facilities. For
permanent magnet undulators, this problem can be overcome by a figure-8
operating mode. But there is still no good method to tackle this problem for
electromagnetic elliptical undulators. Here, a novel operating mode is
suggested, which can generate pure linearly polarized photons with very low
on-axis heat load. Also the available minimum photon energy of linearly
polarized photons can be extended much by this method
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