38,110 research outputs found
Real photons produced from photoproduction in collisions
We calculate the production of real photons originating from the
photoproduction in relativistic collisions. The
Weizscker-Williams approximation in the photoproduction is
considered. Numerical results agree with the experimental data from
Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC). We find
that the modification of the photoproduction is more prominent in large
transverse momentum region.Comment: 2 figure
Guanxi and the organization of Chinese new year festivals in England
This article explores how Chinese diaspora communities use guanxi, a unique Chinese interpretation of personal relationships, in the organization of Chinese New Year (CNY) festivals in England. A case-study approach that incorporated mixed qualitative methods was used to investigate the interactions and interrelationships between the ethnic Chinese communities involved in the organization of CNY festivals in five English cities. The article argues that Chinese diaspora communities use their guanxi to establish collaboration at CNY festivals. However, the process of organizing CNY festivals has also exposed divisions among Chinese communities. The article proposes that guanxi has important implications for the relationships among Chinese diaspora communities in the context of CNY festivals. Although it facilitates collaboration and promotes solidarity among Chinese communities, it may also intensify competition for power. Diaspora festivals in general are a neglected area of research and this article is the first to study the organization of Chinese New Year festivals in detail
The structure of electronic polarization and its strain dependence
The \phi(\kpp)\sim \kpp relation is called polarization structure. By
density functional calculations, we study the polarization structure in
ferroelectric perovskite PbTiO, revealing (1) the \kpp point that
contributes most to the electronic polarization, (2) the magnitude of
bandwidth, and (3) subtle curvature of polarization dispersion. We also
investigate how polarization structure in PbTiO is modified by compressive
inplane strains. The bandwidth of polarization dispersion in PbTiO is shown
to exhibit an unusual decline, though the total polarization is enhanced. As
another outcome of this study, we formulate an analytical scheme for the
purpose of identifying what determine the polarization structure at arbitrary
\kpp points by means of Wannier functions. We find that \phi(\kpp) is
determined by two competing factors: one is the overlaps between neighboring
Wannier functions within the plane {\it perpendicular} to the polarization
direction, and the other is the localization length {\it parallel} to the
polarization direction. Inplane strain increases the former while decreases the
latter, causing interesting non-monotonous effects on polarization structure.
Finally, polarization dispersion in another paradigm ferroelectric BaTiO is
discussed and compared with that of PbTiO.Comment: 5 Figure
Metal-free activation of H<sub>2</sub>O<sub>2</sub> by g-C<sub>3</sub>N<sub>4</sub> under visible light irradiation for the degradation of organic pollutants
On Mitigation of Side-Channel Attacks in 3D ICs: Decorrelating Thermal Patterns from Power and Activity
Various side-channel attacks (SCAs) on ICs have been successfully
demonstrated and also mitigated to some degree. In the context of 3D ICs,
however, prior art has mainly focused on efficient implementations of classical
SCA countermeasures. That is, SCAs tailored for up-and-coming 3D ICs have been
overlooked so far. In this paper, we conduct such a novel study and focus on
one of the most accessible and critical side channels: thermal leakage of
activity and power patterns. We address the thermal leakage in 3D ICs early on
during floorplanning, along with tailored extensions for power and thermal
management. Our key idea is to carefully exploit the specifics of material and
structural properties in 3D ICs, thereby decorrelating the thermal behaviour
from underlying power and activity patterns. Most importantly, we discuss
powerful SCAs and demonstrate how our open-source tool helps to mitigate them.Comment: Published in Proc. Design Automation Conference, 201
Beyond relativistic mean-field studies of low-lying states in neutron-deficient krypton isotopes
Neutron-deficient krypton isotopes are of particular interest due to the
coexistence of oblate and prolate shapes in low-lying states and the transition
of ground-state from one dominate shape to another as a function of neutron
number. A detailed interpretation of these phenomena in neutron-deficient Kr
isotopes requires the use of a method going beyond a mean-field approach that
permits to determine spectra and transition probabilities. The aim of this work
is to provide a systematic calculation of low-lying state in the even-even
68-86Kr isotopes and to understand the shape coexistence phenomenon and the
onset of large collectivity around N=40 from beyond relativistic mean-field
studies. The starting point of our method is a set of relativistic
mean-field+BCS wave functions generated with a constraint on triaxial
deformations (beta, gamma). The excitation energies and electric multipole
transition strengths of low-lying states are calculated by solving a
five-dimensional collective Hamiltonian (5DCH) with parameters determined by
the mean-field wave functions. To examine the role of triaxiality, a
configuration mixing of both particle number (PN) and angular momentum (AM)
projected axially deformed states is also carried out within the exact
generator coordinate method (GCM) based on the same energy density functional.
The energy surfaces, the excitation energies of 0^+_2, 2^+_1, 2^+_2 states, as
well as the E0 and E2 transition strengths are compared with the results of
similar 5DCH calculations but with parameters determined by the
non-relativistic mean-field wave functions, as well as with the available
data...Comment: 23 pages, 10 figure
Gaps below strange star crusts
The gap caused by a strong electric field between the quark surface and
nuclear crust of a strange star is studied in an improved model including
gravity and pressure as well as electrostatic forces. The transition from gap
to crust is followed in detail. The properties of the gap are investigated for
a wide range of parameters assuming both color-flavor locked and non
color-flavor locked strange star cores. The maximally allowed crust density is
generally lower than that of neutron drip. Finite temperature is shown to
increase the gap width, but the effect is significant only at extreme
temperatures. Analytical approximations are derived and shown to provide useful
fits to the numerical results.Comment: 12 pages incl. 14 figures. To appear in Physical Review
- …