815 research outputs found
Improving the Efficiency of the State Budget Balance in Vietnam
The state budget balance is always an extremely important issue for each government. In 2020, Vietnam has a relatively small-scale economy. Its economic scale and GDP per capita reached 271.2 billion USD and 2,779 USD respectively. Budget revenue is still limited, but the need for recurrent spending and development investment is still very large now and in many years to come. In the past time, budget revenue and expenditure are in a situation of not having the necessary balance, the state budget deficit has been still around 4.5 percent of GDP. The actual state budget revenue and expenditure balance have been revealing several disadvantages. Faced to such a situation, the author would like to present some important issues about the state budget revenue and expenditure and propose key solutions to increase the efficiency of state budget revenue and expenditure in Vietnam
Folding model study of the elastic scattering at low energies
The folding model analysis of the elastic scattering at the
incident energies below the reaction threshold of 34.7 MeV (in the lab system)
has been done using the well-tested density dependent versions of the M3Y
interaction and realistic choices for the He density. Because the
absorption is negligible at the energies below the reaction threshold, we were
able to probe the optical potential at low energies quite
unambiguously and found that the overlap density used to
construct the density dependence of the M3Y interaction is strongly distorted
by the Pauli blocking. This result gives possible explanation of a
long-standing inconsistency of the double-folding model in its study of the
elastic and -nucleus scattering at low energies using
the same realistic density dependent M3Y interaction
The prospects of rainwater harvesting in the Ho CHi Minh City
Wisely using natural water resources to serve human needs plays a decisive role in ensuring water and food security. In the natural water cycle, rainwater is considered as a valuable renewable resource. Rainwater harvesting (RWH) for daily life and production is a simple but effective and also environmentally sound measure. It is also a positive solution in a climate change adaptation strategy. However, this resource is being wasted in our country in general and in the HCM City in particular. This paper provides an overview of the status of rainwater use in the world; the general situation, the potential of rainwater collection and a number of issues related to the potential of rainwater harvesting in the city. Some solutions to enhance the use of rainwater and improve water supply for city residents are also suggested in this discussion
Neutron star cooling - a challenge to the nuclear mean field
The two recent density-dependent versions of the finite-range M3Y interaction
(CDM3Y and M3Y-P) have been probed against the bulk properties of
asymmetric nuclear matter (NM) in the nonrelativistic Hartree Fock (HF)
formalism. The same HF study has also been done with the famous Skyrme (SLy4)
and Gogny (D1S and D1N) interactions which were well tested in the nuclear
structure calculations. Our HF results are compared with those given by other
many-body calculations like the Dirac-Brueckner Hartree-Fock approach or
ab-initio variational calculation using free nucleon-nucleon interaction, and
by both the nonrelativistic and relativistic mean-field studies using different
model parameters. Although the two considered density-dependent versions of the
M3Y interaction were proven to be quite realistic in the nuclear structure or
reaction studies, they give two distinct behaviors of the NM symmetry energy at
high densities, like the Asy-soft and Asy-stiff scenarios found earlier with
other mean-field interactions. As a consequence, we obtain two different
behaviors of the proton fraction in the -equilibrium which in turn can
imply two drastically different mechanisms for the neutron star cooling. While
some preference of the Asy-stiff scenario was found based on predictions of the
latest microscopic many-body calculations or empirical NM pressure and isospin
diffusion data deduced from heavy-ion collisions, a consistent mean-field
description of nuclear structure database is more often given by some Asy-soft
type interaction like the Gogny or M3Y-P ones. Such a dilemma poses an
interesting challenge to the modern mean-field approaches.Comment: Version accepted for publication in Phys. Rev.
Piezoresistive effect of p-type single crystalline 3C-SiC on (111) plane
This paper presents for the first time the effect of strain on the electrical conductivity of p-type single crystalline 3C-SiC grown on a Si (111) substrate. 3C-SiC thin film was epitaxially formed on a Si (111) substrate using the low pressure chemical vapor deposition process. The piezoresistive effect of the grown film was investigated using the bending beam method. The average longitudinal gauge factor of the p-type single crystalline 3C-SiC was found to be around 11 and isotropic in the (111) plane. This gauge factor is 3 times smaller than that in a p-type 3C-SiC (100) plane. This reduction of the gauge factor was attributed to the high density of defects in the grown 3C-SiC (111) film. Nevertheless, the gauge factor of the p-type 3C-SiC (111) film is still approximately 5 times higher than that in most metals, indicating its potential for niche mechanical sensing applications
Preparation of an Exponentially Rising Optical Pulse for Efficient Excitation of Single Atoms in Free Space
We report on a simple method to prepare optical pulses with exponentially
rising envelope on the time scale of a few ns. The scheme is based on the
exponential transfer function of a fast transistor, which generates an
exponentially rising envelope that is transferred first on a radio frequency
carrier, and then on a coherent cw laser beam with an electro-optical phase
modulator (EOM). The temporally shaped sideband is then extracted with an
optical resonator and can be used to efficiently excite a single Rb-87 atom.Comment: 3 pages, 4 figures, small technical not
Isospin dependence of 6He+p optical potential and the symmetry energy
A consistent folding analysis of the elastic p(6He,6He)p scattering and
charge exchange p(6He,6Li*)n reaction data measured at Elab=41.6A MeV has been
performed within the coupled channels formalism. We have used the isovector
coupling to link the isospin dependence of 6He+p optical potential to the cross
section of p(6He,6Li*)n reaction exciting the 0+ isobaric analog state (IAS) at
3.563 MeV in 6Li. Based on these results and the Hartree-Fock calculation of
asymmetric nuclear matter using the same isospin-dependent effective
nucleon-nucleon interaction, we were able to confirm that the most realistic
value of the symmetry energy Esym is around 31 MeV. Our analysis has also shown
that the measured charge exchange p(6He,6Li*)n data are quite sensitive to the
halo tail of the 6He density used in the folding calculation and the IAS of 6Li
is likely to have a halo structure similar to that established for the ground
state of 6He.Comment: Accepted for publication in Phys. Rev.
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