2,889,907 research outputs found
High energy density electrochemical cell
Primary cell has an anode of lithium, a cathode containing dihaloisocyanuric acid, and a nonaqueous electrolyte comprised of a solution of lithium perchlorate in methyl formate. It produces an energy density of 213 watt hrs/lb and can achieve a high current density
Probing the density dependence of the symmetry energy by nucleon flow
In the framework of the isospin-dependent Boltzmann-Uehling-Uhlenbeck
transport model, sensitive regions of some nucleon observables to the nuclear
symmetry energy are studied. It is found that the symmetry energy sensitive
observable n/p ratio in the Sn+Sn reaction at 0.3 GeV/nucleon
in fact just probes the density-dependent symmetry energy below the density of
and effectively probes the density-dependent symmetry energy around
or somewhat below the saturation density. Nucleon elliptic flow can probe the
symmetry energy from the low-density region to the high-density region when
changing the incident beam energies from 0.3 to 0.6 GeV/nucleon in the
semi-central Sn+Sn reaction. And nucleon transverse and
elliptic flows in the semi-central Au+Au reaction at 0.6
GeV/nucleon are more sensitive to the high-density behavior of the nuclear
symmetry energy. One thus concludes that nucleon observables in the heavy
reaction system and with higher incident beam energy are more suitable to be
used to probe the high-density behavior of the symmetry energy. The present
study may help one to get more specific information about the density-dependent
symmetry energy from nucleon flow observable in heavy-ion collisions at
intermediate energies.Comment: 5 pages, 6 figure
Effective theory for low-energy nuclear energy density functionals
We introduce a new class of effective interactions to be used within the
energy-density-functional approaches. They are based on regularized zero-range
interactions and constitute a consistent application of the effective-theory
methodology to low-energy phenomena in nuclei. They allow for defining the
order of expansion in terms of the order of derivatives acting on the
finite-range potential. Numerical calculations show a rapid convergence of the
expansion and independence of results of the regularization scale.Comment: 5 RevTex pages, 5 figures, misprints corrected, extended version, see
also http://iopscience.iop.org/0954-3899/labtalk-article/5109
Ultralocal energy density in massive gravity
We provide a space-time covariant Hamiltonian treatment for a finite-range
gravitational theory. The Kuchar approach is used to demonstrate the bimetric
picture of space-time in its most transparent form. This Hamiltonian formalism
is applied for the straightforward realization of the Poincar\'e algebra in
Dirac brackets. It uncovers the simplest form of the Poincar\'e generators
expressed as spatial integrals of ultralocal quantities constructed pure
algebraically by means of the two space-time metrics.Comment: 17 pages, no figures, LaTe
Relativistic nuclear energy density functional constrained by low-energy QCD
A relativistic nuclear energy density functional is developed, guided by two
important features that establish connections with chiral dynamics and the
symmetry breaking pattern of low-energy QCD: a) strong scalar and vector fields
related to in-medium changes of QCD vacuum condensates; b) the long- and
intermediate-range interactions generated by one-and two-pion exchange, derived
from in-medium chiral perturbation theory, with explicit inclusion of
excitations. Applications are presented for binding energies,
radii of proton and neutron distributions and other observables over a wide
range of spherical and deformed nuclei from to . Isotopic
chains of and nuclei are studied as test cases for the isospin
dependence of the underlying interactions. The results are at the same level of
quantitative comparison with data as the best phenomenological relativistic
mean-field models.Comment: 48 pages, 12 figures, elsart.cls class file. Revised version,
accepted for publication in Nucl. Phys.
Energy-momentum Density of Gravitational Waves
In this paper, we elaborate the problem of energy-momentum in general
relativity by energy-momentum prescriptions theory. Our aim is to calculate
energy and momentum densities for the general form of gravitational waves. In
this connection, we have extended the previous works by using the prescriptions
of Bergmann and Tolman. It is shown that they are finite and reasonable. In
addition, using Tolman prescription, exactly, leads to same results that have
been obtained by Einstein and Papapetrou prescriptions.Comment: LaTeX, 9 pages, 1 table: added reference
Dark energy density predicted and explained
It has recently been shown that the observed Hubble function for cosmological
expansion can be fitted accurately back to redshift unity (7.33 Gyr ago) with
only one free constant, while neglecting cosmic curvature and mass, using the
modified Friedmann equation implied by subjecting the Higgs scalar field model
to conformal Weyl scaling symmetry. Time-dependent solutions of the
relativistic conformal Higgs scalar field equation coupled with the conformal
Friedmann equation are shown here to imply dark energy of the observed
magnitude. Predicted persistent cosmic acceleration is consistent with the
nonclassical parameter inferred by conformal theory from observed excessive
galactic rotation velocities and galactic dark halos, all without dark matter.Comment: 6 pages MS revised abstract, text, and references. Accepted for
Europhysics Letter
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