221,987 research outputs found
Propagation of the 2012 March Coronal Mass Ejections from the Sun to Heliopause
In 2012 March the Sun exhibited extraordinary activities. In particular, the
active region NOAA AR 11429 emitted a series of large coronal mass ejections
(CMEs) which were imaged by STEREO as it rotated with the Sun from the east to
west. These sustained eruptions are expected to generate a global shell of
disturbed material sweeping through the heliosphere. A cluster of shocks and
interplanetary CMEs (ICMEs) were observed near the Earth, and are propagated
outward from 1 AU using an MHD model. The transient streams interact with each
other, which erases memory of the source and results in a large merged
interaction region (MIR) with a preceding shock. The MHD model predicts that
the shock and MIR would reach 120 AU around 2013 April 22, which agrees well
with the period of radio emissions and the time of a transient disturbance in
galactic cosmic rays detected by Voyager 1. These results are important for
understanding the "fate" of CMEs in the outer heliosphere and provide
confidence that the heliopause is located around 120 AU from the Sun.Comment: 13 pages, 5 figures, accepted for publication in ApJ Letter
A New Spin Gapless Semiconductors Family: Quaternary Heusler Compounds
Using first-principles calculations, we investigate the band structures of a
series of quaternary LiMgPdSn-type Heusler compounds. Our calculation results
show that five compounds CoFeMnSi, CoFeCrAl, CoMnCrSi, CoFeVSi and FeMnCrSb
possess unique electronic structures characterized by a half-metallic gap in
one spin direction while a zero-width gap in the other spin direction showing
spin gapless semiconducting behavior. We further analysis the electronic and
magnetic properties of all quaternary Heusler alloys involved, and reveal a
semi-empirical general rule (total valence electrons number being 26 or 28) for
indentifying spin gapless semiconductors in Heusler compounds. The influences
of lattice distortion and main-group element change have also been discussed.Comment: 20 pages, 5 figures, 1 supplementary file, submitted for publicatio
Urban Regeneration of Industrial Areas: Affordable Housing for Low Income Populations in Cities
The UK-China Sustainable Development Dialogue (SDD) is a partnership between the UK and Chinese Governments to promote collaboration and good practice on sustainable development. It is framed by a 2004 joint Prime Ministerial declaration and was formally established in 2005 by an agreement signed by UK Deputy Prime Minister John Prescott and State Councillor Tang. The SDD was founded on the recognition that, in an interdependent world, international co-operation is needed to ensure that learning is shared and efforts are made collectively towards achieving common goals. This report is the 13th and Final Paper in the SDD (Urban Strand. It draws together the core conclusions from the previous twelve papers and offers recommendations for taking the dialogue forward
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