4,042 research outputs found
The determinants of dividend policy on Chinese high-tech firms
The purpose of this study is to investigate the relationship between dividend payout ratio in Chinese High-tech firms with profitability, firm size, growth opportunities, leverage and liquidity. The study used a sample of 226 firms listed on the Shenzhen stock exchange and Shanghai stock exchange. These firms were taken from high technology industry sector in China. In order to explain the relationships as stated above, ordinary least squares regression analysis is used to test the hypotheses. The study found that at the pooled data level for whole study period, profitability, growth opportunity, liquidity and firm size have significant positive correlation with dividend payout ratio(DPR). The variable leverage, however, has a strong negative correlation with dividend payout ratio. The findings however differ from term to term (short term, medium term and long term); results reflect that leverage is the common variables which have influence on DPR across various terms, where profitability, growth opportunity, liquidity and firm size are not significantly associated with DPR in short term (0-3 years). Similarly, profitability, liquidity and growth opportunity have no influence on the dividend payout ratio of the companies in the medium term (4-7 years). All variables have significant influence on DPR except growth opportunity
Temperature effects on the nuclear symmetry energy and symmetry free energy with an isospin and momentum dependent interaction
Within a self-consistent thermal model using an isospin and momentum
dependent interaction (MDI) constrained by the isospin diffusion data in
heavy-ion collisions, we investigate the temperature dependence of the symmetry
energy and symmetry free energy for hot,
isospin asymmetric nuclear matter. It is shown that the symmetry energy
generally decreases with increasing temperature while the
symmetry free energy exhibits opposite temperature
dependence. The decrement of the symmetry energy with temperature is
essentially due to the decrement of the potential energy part of the symmetry
energy with temperature. The difference between the symmetry energy and
symmetry free energy is found to be quite small around the saturation density
of nuclear matter. While at very low densities, they differ significantly from
each other. In comparison with the experimental data of temperature dependent
symmetry energy extracted from the isotopic scaling analysis of intermediate
mass fragments (IMF's) in heavy-ion collisions, the resulting density and
temperature dependent symmetry energy is then used to
estimate the average freeze-out density of the IMF's.used to estimate the
average freeze-out density of the IMF's.Comment: 9 pages, 7 figures, 1 figure added to show the temperature dependence
of the potential and kinetic parts of the symmetry energy. Revised version to
appear in PR
Energy dependence of pion in-medium effects on \pi^-/\pi^+ ratio in heavy-ion collisions
Within the framework of a thermal model with its parameters fitted to the
results from an isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport
model, we study the pion in-medium effect on the charged-pion ratio in
heavy-ion collisions at various energies. We find that due to the cancellation
between the effects from pion-nucleon s-wave and p-wave interactions in nuclear
medium, the \pi^-/\pi^+ ratio generally decreases after including the pion
in-medium effect. The effect is larger at lower collision energies as a result
of narrower pion spectral functions at lower temperatures.Comment: 4 pages, 4 figures, 1 table, minor modifications, version to appear
in Physical Review
Shear viscosity of neutron-rich nucleonic matter near its liquid-gas phase transition
Within a relaxation time approach using free nucleon-nucleon cross sections
modified by the in-medium nucleon masses that are determined from an isospin-
and momentum-dependent effective nucleon-nucleon interaction, we investigate
the specific shear viscosity () of neutron-rich nucleonic matter near
its liquid-gas phase transition. It is found that as the nucleonic matter is
heated at fixed pressure or compressed at fixed temperature, its specific shear
viscosity shows a valley shape in the temperature or density dependence, with
the minimum located at the boundary of the phase transition. Moreover, the
value of drops suddenly at the first-order liquid-gas phase transition
temperature, reaching as low as times the KSS bound of .
However, it varies smoothly for the second-order liquid-gas phase transition.
Effects of the isospin degree of freedom and the nuclear symmetry energy on the
value of are also discussed.Comment: 6 pages, 5 figure
Differential isospin-fractionation in dilute asymmetric nuclear matter
The differential isospin-fractionation (IsoF) during the liquid-gas phase
transition in dilute asymmetric nuclear matter is studied as a function of
nucleon momentum. Within a self-consistent thermal model it is shown that the
neutron/proton ratio of the gas phase becomes {\it smaller} than that of the
liquid phase for energetic nucleons, although the gas phase is overall more
neutron-rich. Clear indications of the differential IsoF consistent with the
thermal model predictions are demonstrated within a transport model for
heavy-ion reactions. Future comparisons with experimental data will allow us to
extract critical information about the momentum dependence of the isovector
strong interaction.Comment: Rapid Communication, Phys. Rev. C (2007) in pres
Nuclear symmetry potential in the relativistic impulse approximation
Using the relativistic impulse approximation with the Love-Franey \textsl{NN}
scattering amplitude developed by Murdock and Horowitz, we investigate the
low-energy (100 MeV MeV) behavior of the nucleon
Dirac optical potential, the Schr\"{o}dinger-equivalent potential, and the
nuclear symmetry potential in isospin asymmetric nuclear matter. We find that
the nuclear symmetry potential at fixed baryon density decreases with
increasing nucleon energy. In particular, the nuclear symmetry potential at
saturation density changes from positive to negative values at nucleon kinetic
energy of about 200 MeV. Furthermore,the obtained energy and density dependence
of the nuclear symmetry potential is consistent with those of the isospin- and
momentum-dependent MDI interaction with , which has been found to describe
reasonably both the isospin diffusion data from heavy-ion collisions and the
empirical neutron-skin thickness of Pb.Comment: 8 pages, 5 figures, revised version to appear in PR
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