447 research outputs found
Relativistic Energy Density Functional Description of Shape Transition in Superheavy Nuclei
Relativistic energy density functionals (REDF) provide a complete and
accurate, global description of nuclear structure phenomena. A modern
semi-empirical functional, adjusted to the nuclear matter equation of state and
to empirical masses of deformed nuclei, is applied to studies of shapes of
superheavy nuclei. The theoretical framework is tested in a comparison of
calculated masses, quadrupole deformations, and potential energy barriers to
available data on actinide isotopes. Self-consistent mean-field calculations
predict a variety of spherical, axial and triaxial shapes of long-lived
superheavy nuclei, and their alpha-decay energies and half-lives are compared
to data. A microscopic, REDF-based, quadrupole collective Hamiltonian model is
used to study the effect of explicit treatment of collective correlations in
the calculation of Q{\alpha} values and half-lives.Comment: 23 pages, 10 figure
Relativistic mean field study of the properties of Z=117 nucleus and the decay chains of 117 isotopes
We have calculated the binding energy, root-mean-square radius and quadrupole
deformation parameter for the recently synthesized superheavy element Z=117,
using the axially deformed relativistic mean field (RMF) model. The calculation
is extended to various isotopes of Z=117 element, strarting from A=286 till
A=310. We predict almost spherical structures in the ground state for almost
all the isotopes. A shape transition appears at about A=292 from prolate to a
oblate shape structures of Z=117 nucleus in our mean field approach. The most
stable isotope (largest binding energy per nucleon) is found to be the
117 nucleus. Also, the Q-value of -decay and the
half-lives are calculated for the -decay chains of
117 and 117, supporting the magic numbers at N=172 and/ or 184.Comment: 6 Pages and 8 Figure
Echocardiographic evaluation of right ventricular systolic function: The traditional and innovative approach
Estimation of right ventricular (RV) performance still remains technically challenging due to its anatomical and functional distinctiveness. The current guidelines for the echocardiographic quantification of RV function recommend using multiple indices to describe the RV in a thorough and comprehensive manner, such as RV index of myocardial performance, tricuspid annular plane systolic excursion, fractional area change, Doppler tissue imaging-derived tricuspid lateral annular systolic velocity (S’-wave), three-dimensional RV ejection fraction (3D RVEF), RV longitudinal strain (RVLS)/strain rate by speckle- tracking echocardiography (STE). Among these, the last one mentioned here is an innovative and a particularly promising tool that yields more precise information about complex regional and global RV mechanics. STE was initially designed to evaluate left ventricular function, but recently it has been introduced to assess RV performance, which is difficult due to its unique structure and physiology. Many studies have shown that both free wall and 6-segment RVLS present a stronger correlation with the RVEF assessed by cardiac magnetic resonance than conventional parameters and seem to be more sensitive in detecting myocardial dysfunction at an earlier, subclinical stage
Alpha decay chains study for the recently observed superheavy element Z=117 within the Isospin Cluster Model
The recently observed -decay chains were produced by
the fusion reactions with target and projectile at Dubna
in Russia. The reported cross-sections for the mentioned reaction are
pb and =1.3(+1.5,-0.6) at and
, respectively. The Q-values of -decay and the half-lives
(s) are calculated for the -decay chains of
nuclei, within the framework of Isospin Cluster Model (ICM). In
the ICM model the proximity energy is improved by using the isospin dependent
radius of parent, daughter and alpha particle. The binding energy (i=1,2) of any nucleus of mass number A and atomic number Z was
obtained from a phenomenological and more genaralized BW formula given by
\cite{samanta02}. The calculated results in ICM are compared with the
experimental results and other theoretical Macro-Microscopic(M-M), RMF(with NL3
and SFU Gold forces parameter) model calculations. The estimated values of
-decay half-lives are in good agreement with the recent data. The ICM
calculation is in favor of the persence of magic number at N=172
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