2,949 research outputs found
Advantages of the multinucleon transfer reactions based on 238U target for producing neutron-rich isotopes around N = 126
The mechanism of multinucleon transfer (MNT) reactions for producing
neutron-rich heavy nuclei around N = 126 is investigated within two different
theoretical frameworks: dinuclear system (DNS) model and isospin-dependent
quantum molecular dynamics (IQMD) model. The effects of mass asymmetry
relaxation, N=Z equilibration, and shell closures on production cross sections
of neutron-rich heavy nuclei are investigated. For the first time, the
advantages for producing neutron-rich heavy nuclei around N = 126 is found in
MNT reactions based on 238U target. We propose the reactions with 238U target
for producing unknown neutron-rich heavy nuclei around N = 126 in the future.Comment: 6 pages, 6 figure
Method for fast dispersing carbon nanotube in aqueous solution
The present invention provides a method for fast dispersing carbon nanotubes in an aqueous solution. In this method, the carbon nanotubes are added into an aqueous solution of a nontoxic surfactant, and then dispersed therein through ultrasonic oscillation. This uniform dispersion can maintain high stability for at least two months without aggregation, suspension or precipitation. This dispersion is suitable for calibrating concentration of the carbon nanotubes
IS Per Capita Real GDP Stationary in China¡H Evidence Based on A Panel SURADF Approach
In this study we use newly developed Panel SURADF tests of the Breuer et al., (2001) to investigate the time-series properties of 25 Chinese provinces¡¦ per capita real GDP for the 1952-1998 period. While the other Panel-based unit root tests are joint tests of a unit root for all members of the panel and are incapable of determining the mix of I(0) and I(1) series in the panel setting, the Panel SURADF tests a separate unit-root null hypothesis for each individual panel member and, therefore identifies how many and which series in the panel are stationary processes. The empirical results indicate that for all the provinces studied per capita real GDP are non-stationary, except Hebei, Jeilongjiang, Qinghai and Shaanxi when Breuer et al.¡¦s (2001) Panel SURADF tests are conducted.Per Capita Real GDP Panel Unit Root Tests
Quantifying equilibrium pressure-gradient turbulent boundary layers via a symmetry approach
We propose a theory for predicting the mean velocity and Reynolds shear and
normal stresses profiles in the wake region of equilibrium adverse
pressure-gradient (PG, APG) turbulent boundary layers (TBLs). Firstly, we
explore the PG-induced dilation-symmetry-breaking of the total stress
to construct a modified defect power law for . Crucially, a PG stress
is identified, which quantifies the APG-induced total-stress overshoot
and is proportional to the Clauser PG parameter . The wall-normal
location with peak stress is predicted. The total stress profiles with
arbitrary are transformed into an invariant profile, which is the
ultimate state of the total stress at infinite . This transformation is
equivalent to the outer scaling of the Reynolds shear stress recently-proposed
by Wei & Knopp (JFM, 2023). The Reynolds normal stresses are predicted
accordingly based on the similarity of the Reynolds shear and normal stresses
in the wake region. Secondly, a defect power law is proposed for the stress and
kinetic energy lengths in the wake region. Two critical parameters in the
defect power law are identified to depend on and determine the length
profiles. With the total stress and stress length models, the streamwise
mean-velocity profile is predicted. Especially, an invariant mean velocity
profile is derived, which describes the ultimate state of the mean velocity in
the wake region at infinite . This invariant profile is also equivalent
to the outer scaling of Wei & Knopp. The theory also predicts the variation of
the Coles' wake parameter with , in close agreement with the
empirical relation that correlates hundreds of experimental data. The
predictions are validated with five published DNS, LES, and experimental
databases on the equilibrium APG TBLs.Comment: 24 pages, 11 figure
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