90 research outputs found
Self-organization of quantum-dot pairs by high-temperature droplet epitaxy
The spontaneously formation of epitaxial GaAs quantum-dot pairs was demonstrated on an AlGaAs surface using Ga droplets as a Ga nano-source. The dot pair formation was attributed to the anisotropy of surface diffusion during high-temperature droplet epitaxy
Novel structure for magnetic rotation bands in 60Ni
The self-consistent tilted axis cranking relativistic mean-field theory based
on a point-coupling interaction has been established and applied to investigate
systematically the newly observed shears bands in 60Ni. The tilted angles,
deformation parameters, energy spectra, and reduced M1 and transition
probabilities have been studied in a fully microscopic and self-consistent way
for various configurations and rotational frequencies. It is found the
competition between the configurations and the transitions from the magnetic to
the electric rotations have to be considered in order to reproduce the energy
spectra as well as the band crossing phenomena. The tendency of the
experimental electromagnetic transition ratios B(M1)/B(E2) is in a good
agreement with the data, in particular, the B(M1) values decrease with
increasing spin as expected for the shears mechanism, whose characteristics are
discussed in detail by investigating the various contributions to the total
angular momentum as well.Comment: 17 pages, 5 figure
Roles of IP3R and RyR Ca2+ Channels in Endoplasmic Reticulum Stress and β-Cell Death
OBJECTIVE—Endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of diabetes, but the roles of specific ER Ca2+ release channels in the ER stress–associated apoptosis pathway remain unknown. Here, we examined the effects of stimulating or inhibiting the ER-resident inositol trisphosphate receptors (IP3Rs) and the ryanodine receptors (RyRs) on the induction of β-cell ER stress and apoptosis
Search for the Chiral Magnetic Effect in Au+Au collisions at GeV with the STAR forward Event Plane Detectors
A decisive experimental test of the Chiral Magnetic Effect (CME) is
considered one of the major scientific goals at the Relativistic Heavy-Ion
Collider (RHIC) towards understanding the nontrivial topological fluctuations
of the Quantum Chromodynamics vacuum. In heavy-ion collisions, the CME is
expected to result in a charge separation phenomenon across the reaction plane,
whose strength could be strongly energy dependent. The previous CME searches
have been focused on top RHIC energy collisions. In this Letter, we present a
low energy search for the CME in Au+Au collisions at
GeV. We measure elliptic flow scaled charge-dependent correlators relative to
the event planes that are defined at both mid-rapidity and at
forward rapidity . We compare the results based on the
directed flow plane () at forward rapidity and the elliptic flow plane
() at both central and forward rapidity. The CME scenario is expected
to result in a larger correlation relative to than to , while
a flow driven background scenario would lead to a consistent result for both
event planes[1,2]. In 10-50\% centrality, results using three different event
planes are found to be consistent within experimental uncertainties, suggesting
a flow driven background scenario dominating the measurement. We obtain an
upper limit on the deviation from a flow driven background scenario at the 95\%
confidence level. This work opens up a possible road map towards future CME
search with the high statistics data from the RHIC Beam Energy Scan Phase-II.Comment: main: 8 pages, 5 figures; supplementary material: 2 pages, 1 figur
ATHENA detector proposal — a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider
ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity. This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges
Optimization of the imaginary time step evolution for the Dirac equation
Taking the single neutron levels of 12C in the Fermi sea as examples, the optimization of the imaginary time step (ITS) evolution with the box size and mesh size for the Dirac equation is investigated. For the weakly bound states, in order to reproduce the exact single-particle energies and wave functions, a relatively large box size is required. As long as the exact results can be reproduced, the ITS evolution with a smaller box size converges faster, while for both the weakly and deeply bound states, the ITS evolutions are less sensitive to the mesh size. Moreover, one can find a parabola relationship between the mesh size and the corresponding critical time step, i.e., the largest time step to guarantee the convergence, which suggests that the ITS evolution with a larger mesh size allows larger critical time step, and thus can converge faster to the exact result. These conclusions are very helpful for optimizing the evolution procedure in the future self-consistent calculations. © 2010 Science China Press and Springer-Verlag Berlin Heidelberg.Articl
Macrophyte species strongly affects changes in C, N, and P stocks in shallow lakes after a regime shift from macrophyte to phytoplankton dominance
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Design rules of heteroatom-doped graphene to achieve high performance lithium–sulfur batteries: both strong anchoring and catalysing based on first principles calculation
A number of observations have been reported on chemical capture and catalysis of anchoring materials for lithium-sulfur batteries. Here, we propose the design principles for the chemical functioned graphene as an anchor material to realize both strong chemical trapping and catalysis. Through the first principle, the periodic law is calculated from the theory. Seven different co-doping series were investigated, e.g. MN4@graphene (M = V, Cr, Mn, Fe, Co, Ni, and Cu). From binding energy, partial density of state, and charge density difference analysis, the FeN4 and CrN4 co-doped graphene show good performance for the lithium-sulfur battery from both strong anchoring and catalytic effects. For the most kinds of Li2Sx (x = 1, 2, 4, 6, 8) absorption, two combinations can be achieved, including S-bonding and Li-bonding. The competition between the MS and the NLi shows the main difference of the co-doped configurations. Moreover, the S-bonding systems have better performance for both moderate chemical trapping and strong catalysis. The binding energies of Li2Sx and Li decomposed properties considered as the key descriptors for the rational design of lithium-sulfur battery. Lastly, we offer design rules for high performance lithium-sulfur batteries based on the chemical functional graphene materials.Lin Zhang, Pei Liang, Hai B.Shu, Xiao L. Man, Xiao Q.Du, Dong L.Chao ... et al
Colistin-Tobramycin Combinations Are Superior to Monotherapy Concerning the Killing of Biofilm Pseudomonas aeruginosa
Abundance and Geological Implication of Rare Earth Elements and Yttrium in Coals from the Suhaitu Mine, Wuda Coalfield, Northern China
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