4,358 research outputs found
Low-lying states in Mg: a beyond relativistic mean-field investigation
The recently developed model of three-dimensional angular momentum projection
plus generator coordinate method on top of triaxial relativistic mean-field
states has been applied to study the low-lying states of Mg. The effects
of triaxiality on the low-energy spectra and E0 and E2 transitions are
examined.Comment: 6 pages, 3 figures, 1 table, talk presented at the 17th nuclear
physics conference "Marie and Pierre Curie" Kazimierz Dolny, 22-26th
September 2010, Polan
Rapid structural change in low-lying states of neutron-rich Sr and Zr isotopes
The rapid structural change in low-lying collective excitation states of
neutron-rich Sr and Zr isotopes is tudied by solving a five-dimensional
collective Hamiltonian with parameters determined by both relativistic
mean-field and non-relativistic Skyrme-Hartree-Fock calculations using the
PC-PK1 and SLy4 forces respectively. Pair correlations are treated in BCS
method with either a separable pairing force or a density-dependent zero-range
force. The isotope shifts, excitation energies, electric monopole and
quadrupole transition strengths are calculated and compared with corresponding
experimental data. The calculated results with both the PC-PK1 and SLy4 forces
exhibit a picture of spherical-oblate-prolate shape transition in neutron-rich
Sr and Zr isotopes. Compared with the experimental data, the PC-PK1 (or SLy4)
force predicts a more moderate (or dramatic) change in most of the collective
properties around N=60. The underlying microscopic mechanism responsible for
the rapid transition is discussed.Comment: 10 pages (twocolumn), 10 figure
The largest virialized dark halo in the universe
Using semi-analytic approach, we present an estimate of the properties of the
largest virialized dark halos in the present universe for three different
scenarios of structure formation: SCDM, LCDM and OCDM models. The resulting
virial mass and temperature increase from the lowest values of and 9.8 keV in OCDM, the mid-range values of and 31 keV in LCDM, to the highest values of
, 65 keV in SCDM. As compared with the
largest virialized object seen in the universe, the richest clusters of
galaxies, we can safely rule out the OCDM model. In addition, the SCDM model is
very unlikely because of the unreasonably high virial mass and temperature. Our
computation favors the prevailing LCDM model in which superclusters may be
marginally regarded as dynamically-virialized systems.Comment: 5 pages, Accepted by Int. J. Mod. Phys.
Effect of Astragalus membranaceus (Fisch) Bunge extract on streptozocin-induced diabetic in rats
Purpose: To investigate the effect of Astragalus membranaceus (Fisch.) Bunge. extract (AMBE) on streptozotocin-induced diabetic rats.Methods: The aqueous extract of AMB was obtained by steeping the dried Astragalus membranaceus (Fisch.) Bunge. in water at 60 oC three times, each for 1 h, before first drying in an oven at 100 oC and then freeze-drying the last extract thus obtained. Diabete model rats was induced by a single intraperitoneal injection of a freshly prepared solution of streptozotocin (50 mg/kg). The rats were randomly divided into 6 groups of ten rats each: negative control group, normal control group, reference group (glibenclamide1 mg/kgbody weight) as well as AMB extract groups, namely, 40, 80 and 160 mg/kg body weight. Antihyperglycemic effect was measured by blood glucose and plasma insulin levels. Oxidative stress was evaluated in liver and kidney by antioxidant markers, viz, lipidperoxidation (LPO), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx) and catalase (CAT), while blood serum levels of creatinine and urea were also determined in both diabetic control and treated rats.Results: Compared with diabetic rats, oral administration of AMBE at a concentration of 160 mg/kg daily for 30 days showed a significant decrease in fasting blood glucose (109.438 ± 3.52, p < 0.05) and increased insulin level (13.96 ± 0.74, p < 0.05). Furthermore, it significantly reduced biochemical parameters (serum creatinine, 0.86 ± 0.29, p < 0.05) and serum urea (45.14 ± 1.79, p < 0.05). The treatment also resulted in significant increase in GSH (49.21 ± 2.59, p < 0.05), GPx (11.96 ± 1.16, p < 0.05), SOD (14.13 ± 0.49, p < 0.05), CAT (83.25 ± 3.14, p < 0.05) level in the liver and kidney of diabetic rats.Conclusion: The results suggest that AMBE may effectively normalize impaired antioxidant status in streptozotocin-induced diabetes in a dose-dependent manner. AMBE has a protective effect against lipid peroxidation by scavenging free radicals and is thus capable of reducing the risk of diabetic complications.Keywords: Astragalus membranaceus, Diabetic, Antihyperglycemic, Antioxidant Oxidative stress, Fasting blood glucos
Beyond relativistic mean-field studies of low-lying states in neutron-deficient krypton isotopes
Neutron-deficient krypton isotopes are of particular interest due to the
coexistence of oblate and prolate shapes in low-lying states and the transition
of ground-state from one dominate shape to another as a function of neutron
number. A detailed interpretation of these phenomena in neutron-deficient Kr
isotopes requires the use of a method going beyond a mean-field approach that
permits to determine spectra and transition probabilities. The aim of this work
is to provide a systematic calculation of low-lying state in the even-even
68-86Kr isotopes and to understand the shape coexistence phenomenon and the
onset of large collectivity around N=40 from beyond relativistic mean-field
studies. The starting point of our method is a set of relativistic
mean-field+BCS wave functions generated with a constraint on triaxial
deformations (beta, gamma). The excitation energies and electric multipole
transition strengths of low-lying states are calculated by solving a
five-dimensional collective Hamiltonian (5DCH) with parameters determined by
the mean-field wave functions. To examine the role of triaxiality, a
configuration mixing of both particle number (PN) and angular momentum (AM)
projected axially deformed states is also carried out within the exact
generator coordinate method (GCM) based on the same energy density functional.
The energy surfaces, the excitation energies of 0^+_2, 2^+_1, 2^+_2 states, as
well as the E0 and E2 transition strengths are compared with the results of
similar 5DCH calculations but with parameters determined by the
non-relativistic mean-field wave functions, as well as with the available
data...Comment: 23 pages, 10 figure
The Navigation Engineering in Developed Hydropower Station
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive
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