36,326 research outputs found
Wave Modes in the Magnetospheres of Pulsars and Magnetars
We study the wave propagation modes in the relativistic streaming pair plasma
of the magnetospheres of pulsars and magnetars, focusing on the effect of
vacuum polarization. We show that the combined plasma and vacuum polarization
effects give rise to a vacuum resonance, where ``avoided mode crossing'' occurs
between the extraordinary mode and the (superluminous) ordinary mode. When a
photon propagates from the vacuum-polarization-dominated region at small radii
to the plasma-dominated region at large radii, its polarization state may
undergo significant change across the vacuum resonance. We map out the
parameter regimes (e.g., field strength, plasma density and Lorentz factor)
under which the vacuum resonance occurs and examine how wave propagation is
affected by the resonance. Some possible applications of our results are
discussed, including high-frequency radio emission from pulsars and possibly
magnetars, and optical/IR emission from neutron star surfaces and inner
magnetospheres.Comment: 19 pages, 10 figures. Accepted by MNRA
Occluded Person Re-identification
Person re-identification (re-id) suffers from a serious occlusion problem
when applied to crowded public places. In this paper, we propose to retrieve a
full-body person image by using a person image with occlusions. This differs
significantly from the conventional person re-id problem where it is assumed
that person images are detected without any occlusion. We thus call this new
problem the occluded person re-identitification. To address this new problem,
we propose a novel Attention Framework of Person Body (AFPB) based on deep
learning, consisting of 1) an Occlusion Simulator (OS) which automatically
generates artificial occlusions for full-body person images, and 2) multi-task
losses that force the neural network not only to discriminate a person's
identity but also to determine whether a sample is from the occluded data
distribution or the full-body data distribution. Experiments on a new occluded
person re-id dataset and three existing benchmarks modified to include
full-body person images and occluded person images show the superiority of the
proposed method.Comment: 6 pages, 7 figures, IEEE International Conference of Multimedia and
Expo 201
A new tri-functional azetidine compound for self-curing aqueous-based PU system
[[abstract]]A mono-azetidine compound had been demonstrating a ring opening reaction with carboxylic acid (e.g., trimethylacetic acid, TMAA) and that resulted in an amino ester bond formation at ambient temperature. A triazetidine compound (trimethylolpropane tris(1-azetidinyl)propionate, TMPTA-AZT) was obtained via Michael addition of azetidine (AZT) to trimethylolpropane triacrylate (TMPTA). The carboxylic groups of anionic aqueous-based polyurethanes (PU) served as internal emulsifier, which stabilized PU dispersion and also served as PU curing sites. The triazetidine compound (TMPTA-AZT) was introduced into anionic aqueous-based PU dispersion as a new latent curing agent and that mixture became a single-component self-curable aqueous PU system. A crosslinked PU film was obtained from this PU system on drying at ambient temperature. The final polymer performance properties demonstrated the crosslinking behaviors of this new curing agent, TMPTA-AZT, with carboxylic ion-containing aqueous-based PU resins.[[incitationindex]]SCI[[booktype]]電子
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