27,013 research outputs found
Nuclear stopping and sideward-flow correlation from 0.35A to 200A GeV
The correlation between the nuclear stopping and the scale invariant nucleon
sideward flow at energies ranging from those available at the GSI heavy ion
synchrotron (SIS) to those at the CERN Super Proton Synchrotron (SPS) is
studied within ultrarelativistic quantum molecular dynamics (UrQMD). The
universal behavior of the two experimental observables for various colliding
systems and scale impact parameters are found to be highly correlated with each
other. As there is no phase transition mechanism involved in the UrQMD, the
correlation may be broken down by the sudden change of the bulk properties of
the nuclear matter, such as the formation of quark-gluon plasma (QGP), which
can be employed as a QGP phase transition signal in high-energy heavy ion
collisions. Furthermore, we also point out that the appearance of a breakdown
of the correlation may be a powerful tool for searching for the critical point
on the QCD phase diagram.Comment: 5 pages, 4 figure
Ferroelectricity of Ice Nanotubes inside Carbon Nanotubes
We report that ice nanotubes with odd number of side faces inside carbon
nanotubes exhibit spontaneous electric polarization along its axes direction by
using molecular dynamics simulations. The mechanism of this nanoscale
quasi-one-dimensional ferroelectricity is due to low dimensional confinement
and the orientational order of hydrogen bonds. These ferroelectric fiber
structural materials are different from traditional perovskite structural bulk
materials.Comment: 4 pages and 4 figure
Bulk-fragment and tube-like structures of AuN (N=2-26)
Using the relativistic all-electron density-functional calculations on the
AuN (N=2-26) in the generalized gradient approximation, combined with the
guided simulated annealing, we have found that the two- to three-dimensional
structural transition for AuN occurs between N=13 and 15, and the AuN (16<= N
<=25) prefer also the pyramid-based bulk fragment structures in addition to the
Au20. More importantly, the tubelike structures are found to be the most stable
for Au24 and Au26, offering another powerful structure competitor with other
isomers, e.g., amorphous, bulk fragment, and gold fullerene. The mechanism to
cause these unusual AuN may be attributed to the stronger s-d hybridization and
the d-d interaction enhanced by the relativistic effects.Comment: 12 pages and 3 figure
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