24 research outputs found
The accelerated scaling attractor solution of the interacting agegraphic dark energy in Brans-Dicke theory
We investigate the interacting agegraphic dark energy in Brans-Dicke theory
and introduce a new series general forms of dark sector coupling. As examples,
we select three cases involving a linear interaction form (Model I) and two
nonlinear interaction form (Model II and Model III). Our conclusions show that
the accelerated scaling attractor solutions do exist in these models. We also
find that these interacting agegraphic dark energy modes are consistent with
the observational data. The difference in these models is that nonlinear
interaction forms give more approached evolution to the standard CDM
model than the linear one. Our work implies that the nonlinear interaction
forms should be payed more attention.Comment: 9 pages, 10 figures, accepted in Eur. Phys. J.
Combined constraints on modified Chaplygin gas model from cosmological observed data: Markov Chain Monte Carlo approach
We use the Markov Chain Monte Carlo method to investigate a global
constraints on the modified Chaplygin gas (MCG) model as the unification of
dark matter and dark energy from the latest observational data: the Union2
dataset of type supernovae Ia (SNIa), the observational Hubble data (OHD), the
cluster X-ray gas mass fraction, the baryon acoustic oscillation (BAO), and the
cosmic microwave background (CMB) data. In a flat universe, the constraint
results for MCG model are,
()
,
()
,
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,
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, and ()
.Comment: 12 pages, 1figur
Anomalous Heat Conduction and Anomalous Diffusion in Low Dimensional Nanoscale Systems
Thermal transport is an important energy transfer process in nature. Phonon
is the major energy carrier for heat in semiconductor and dielectric materials.
In analogy to Ohm's law for electrical conductivity, Fourier's law is a
fundamental rule of heat transfer in solids. It states that the thermal
conductivity is independent of sample scale and geometry. Although Fourier's
law has received great success in describing macroscopic thermal transport in
the past two hundreds years, its validity in low dimensional systems is still
an open question. Here we give a brief review of the recent developments in
experimental, theoretical and numerical studies of heat transport in low
dimensional systems, include lattice models, nanowires, nanotubes and
graphenes. We will demonstrate that the phonon transports in low dimensional
systems super-diffusively, which leads to a size dependent thermal
conductivity. In other words, Fourier's law is breakdown in low dimensional
structures
Holographic \Lambda(t)CDM model in a non-flat universe
The holographic CDM model in a non-flat universe is studied in
this paper. In this model, to keep the form of the stress-energy of the vacuum
required by general covariance, the holographic vacuum is enforced to exchange
energy with dark matter. It is demonstrated that for the holographic model the
best choice for the IR cutoff of the effective quantum field theory is the
event horizon size of the universe. We derive the evolution equations of the
holographic CDM model in a non-flat universe. We constrain the
model by using the current observational data, including the 557 Union2 type Ia
supernovae data, the cosmic microwave background anisotropy data from the 7-yr
WMAP, and the baryon acoustic oscillation data from the SDSS. Our fit results
show that the holographic CDM model tends to favor a spatially
closed universe (the best-fit value of is -0.042), and the 95%
confidence level range for the spatial curvature is .
We show that the interaction between the holographic vacuum and dark matter
induces an energy flow of which the direction is first from vacuum to dark
matter and then from dark matter to vacuum. Thus, the holographic
CDM model is just a time-varying vacuum energy scenario in which
the interaction between vacuum and dark matter changes sign during the
expansion of the universe.Comment: 8 pages, 4 figures. version for publication in EPJC. arXiv admin
note: text overlap with arXiv:1112.235
Modificaciones físicas, químicas y enzimáticas y sus efectos sobre las propiedades de las películas de quitosano
A quantitative assessment of human impacts on decrease in sediment flux from major Chinese rivers entering the western Pacific Ocean
10.1029/2009GL039513Geophysical Research Letters3619GPRL
A quantitative assessment of human impacts on decrease in sediment flux from major Chinese rivers entering the western Pacific Ocean
Geophysical Research Letters3619GPRL