209 research outputs found
A comparative study of super- and highly-deformed bands in the A ~ 60 mass region
Super- and highly-deformed rotational bands in the A ~ 60 mass region are
studied within cranked relativistic mean field theory and the
configuration-dependent shell-correction approach based on the cranked Nilsson
potential. Both approaches describe the experimental data well. Low values of
the dynamic moments of inertia J^(2) compared with the kinematic moments of
inertia J^(1) seen both in experiment and in calculations at high rotational
frequencies indicate the high energy cost to build the states at high spin and
reflect the limited angular momentum content in these configurations.Comment: 11 pages, 4 PostScript figures, Latex, uses 'epsf', submitted to
Phys. Lett.
Time-odd mean fields in the rotating frame: microscopic nature of nuclear magnetism
The microscopic role of nuclear magnetism in rotating frame is investigated
for the first time in the framework of the cranked relativistic mean field
theory. It is shown that nuclear magnetism modifies the expectation values of
single-particle spin, orbital and total angular momenta along the rotational
axis effectively creating additional angular momentum. This effect leads to the
increase of kinematic and dynamic moments of inertia at given rotational
frequency and has an impact on effective alignments.Comment: 16 pages, 4 figures, submitted to Physical Review
Time-odd mean fields in covariant density functional theory: Rotating systems
Time-odd mean fields (nuclear magnetism) and their impact on physical
observables in rotating nuclei are studied in the framework of covariant
density functional theory (CDFT). It is shown that they have profound effect on
the dynamic and kinematic moments of inertia. Particle number, configuration
and rotational frequency dependences of their impact on the moments of inertia
have been analysed in a systematic way. Nuclear magnetism can also considerably
modify the band crossing features such as crossing frequencies and the
properties of the kinematic and dynamic moments of inertia in the band crossing
region. The impact of time-odd mean fields on the moments of inertia in the
regions away from band crossing only weakly depends on the relativistic mean
field parametrization, reflecting good localization of the properties of
time-odd mean fields in CDFT. The moments of inertia of normal-deformed nuclei
considerably deviate from the rigid body value. On the contrary, superdeformed
and hyperdeformed nuclei have the moments of inertia which are close to rigid
body value. The structure of the currents in rotating frame, their microscopic
origin and the relations to the moments of inertia have been systematically
analysed. The phenomenon of signature separation in odd-odd nuclei, induced by
time-odd mean fields, has been analysed in detail.Comment: 20 pages. 16 figure
Central depression in nuclear density and its consequences for the shell structure of superheavy nuclei
The influence of the central depression in the density distribution of
spherical superheavy nuclei on the shell structure is studied within the
relativistic mean field theory. Large depression leads to the shell gaps at the
proton Z=120 and neutron N=172 numbers, while flatter density distribution
favors N=184 for neutrons and leads to the appearance of a Z=126 shell gap and
to the decrease of the size of the Z=120 shell gap. The correlations between
the magic shell gaps and the magnitude of central depression are discussed for
relativistic and non-relativistic mean field theories.Comment: 5 page
Probing the gateway to superheavy nuclei in cranked relativistic Hartree-Bogoliubov theory
The cranked relativistic Hartree+Bogoliubov theory has been applied for a
systematic study of the nuclei around 254No, the heaviest nuclei for which
detailed spectroscopic data are available. The deformation, rotational
response, pairing correlations, quasi-particle and other properties of these
nuclei have been studied with different relativistic mean field (RMF)
parametrizations. For the first time, the quasi-particle spectra of odd
deformed nuclei have been calculated in a fully self-consistent way within the
framework of the RMF theory. The energies of the spherical subshells, from
which active deformed states of these nuclei emerge, are described with an
accuracy better than 0.5 MeV for most of the subshells with the NL1 and NL3
parametrizations. However, for a few subshells the discrepancy reach 0.7-1.0
MeV. The implications of these results for the study of superheavy nuclei are
discussed.Comment: 7 pages, 3 figures, Proceedings of the Conference on Frontiers of
Nuclear Structure, Berkeley, California, July 29th - August 2nd, 2002, UC
Berkeley, Clark Kerr Campus, in pres
Recent progress in the study of fission barriers in covariant density functional theory
Recent progress in the study of fission barriers of actinides and superheavy
nuclei within covariant density functional theory is overviewed.Comment: 10 pages, 5 figures. In press in International Journal of Modern
Physics
FATTENING CAPACITIES AND MEAT QUALITY OF JAPANESE QUAILS OF FARAON AND WHITE ENGLISH BREEDS
The aim of the study was to establish the fatting capacity and the meat quality of the combined (meat+eggs) White English breed and to compare with the same of the meat Faraon breed. Logically, the live weight of 31-day old male Faraon-birds was by 5,9 % higher and of the female ones – by 7,9 % compared to the birds of White English breed. Feed conversion ratio for the experimental period (3-31 days) for the White English quails was to 9,95% less effective, compared to the Faraon birds. The meat of Faraon quails contained more dry matter and protein compared to the meat of White English breed. Fat content in the quail bodies of White English breed was signifi cantly lower compared to Faraon breed /Р≤0,05/. Quail meat of White English breed was characterized by its better capacity for technological processing due to the lower loss of moisture – by 18,8 % for breast and 22,4 % for leg muscles /Р≤0,05/. The established results characterize the combined White English breed as suitable for producing both of eggs and meat from quails
- …