18,314 research outputs found
A new small satellite sunspot triggering recurrent standard- and blowout-coronal jets
In this paper,we report a detailed analysis of recurrent jets originated from
a location with emerging, canceling and converging negative magnetic field at
the east edge of NOAA active region AR11166 from 2011 March 09 to 10. The event
presented several interesting features. First, a satellite sunspot appeared and
collided with a pre-existing opposite polarity magnetic field and caused a
recurrent solar jet event. Second, the evolution of the jets showed
blowout-like nature and standard characteristics. Third, the satellite sunspot
exhibited a motion toward southeast of AR11166 and merged with the emerging
flux near the opposite polarity sunspot penumbra, which afterward, due to flux
convergence and cancellation episodes, caused recurrent jets. Fourth, three of
the blowout jets associated with coronal mass ejections (CMEs), were observed
from field of view of the Solar Terrestrial Relations Observatory. Fifth,
almost all the blowout jet eruptions were accompanied with flares or with more
intense brightening in the jet base region, while almost standard jets did not
manifest such obvious feature during eruptions. The most important, the blowout
jets were inclined to faster and larger scale than the standard jets. The
standard jets instead were inclined to relative longer-lasting. The obvious
shearing and twisting motions of the magnetic field may be interpreted as due
to the shearing and twisting motions for a blowout jet eruption. From the
statistical results, about 30% blowout jets directly developed into CMEs. It
suggests that the blowout jets and CMEs should have a tight relationship.Comment: ApJ 18 pages, 7 figure
Reversible Embedding to Covers Full of Boundaries
In reversible data embedding, to avoid overflow and underflow problem, before
data embedding, boundary pixels are recorded as side information, which may be
losslessly compressed. The existing algorithms often assume that a natural
image has little boundary pixels so that the size of side information is small.
Accordingly, a relatively high pure payload could be achieved. However, there
actually may exist a lot of boundary pixels in a natural image, implying that,
the size of side information could be very large. Therefore, when to directly
use the existing algorithms, the pure embedding capacity may be not sufficient.
In order to address this problem, in this paper, we present a new and efficient
framework to reversible data embedding in images that have lots of boundary
pixels. The core idea is to losslessly preprocess boundary pixels so that it
can significantly reduce the side information. Experimental results have shown
the superiority and applicability of our work
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Design Principles for High-Capacity Mn-Based Cation-Disordered Rocksalt Cathodes
Mn-based Li-excess cation-disordered rocksalt (DRX) oxyfluorides are promising candidates for next-generation rechargeable battery cathodes owing to their large energy densities, the earth abundance, and low cost of Mn. In this work, we synthesized and electrochemically tested four representative compositions in the Li-Mn-O-F DRX chemical space with various Li and F content. While all compositions achieve higher than 200 mAh g−1 initial capacity and good cyclability, we show that the Li-site distribution plays a more important role than the metal-redox capacity in determining the initial capacity, whereas the metal-redox capacity is more closely related to the cyclability of the materials. We apply these insights and generate a capacity map of the Li-Mn-O-F chemical space, LixMn2-xO2-yFy (1.167 ≤ x ≤ 1.333, 0 ≤ y ≤ 0.667), which predicts both accessible Li capacity and Mn-redox capacity. This map allows the design of compounds that balance high capacity with good cyclability
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