1,510 research outputs found
Microscopic Determinations of Fission Barriers, (MEAN-Field and Beyond)
With a help of the selfconsistent Hartree-Fock-Bogoliubov (HFB) approach with
the D1S effective Gogny interaction and the Generator Coordinate Method (GCM)
we incorporate the transverse collective vibrations to the one-dimensional
model of the fission-barrier penetrability based on the traditional WKB method.
The average fission barrier corresponding to the least-energy path in the
two-dimensional potential energy landscape as function of quadrupole and
octupole degrees of freedom is modified by the influence of the transverse
collective vibrations along the nuclear path to fission. The set of transverse
vibrational states built in the fission valley corresponding to a successively
increasing nuclear elongation produces the new energy barrier which is compared
with the least-energy barrier. These collective states are given as the
eigensolutions of the GCM purely vibrational Hamiltonian. In addition, the
influence of the collective inertia on the fission properties is displayed, and
it turns out to be the decisive condition for the possible transitions between
different fission valleys.Comment: 12 pages, 5 figures, presented at XIII Workshop of Nuclear Physics,
Kazimierz Dolny, 2006 (Poland
Curvature Correction in the Strutinsky's Method
Mass calculations carried out by Strutinsky's shell correction method are
based on the notion of smooth single particle level density. The smoothing
procedure is always performed using curvature correction. In the presence of
curvature correction a smooth function remains unchanged if smoothing is
applied. Two new curvature correction methods are introduced. The performance
of the standard and new methods are investigated using harmonic oscillator and
realistic potentials.Comment: 4 figures, submitted to Journal of Physics G: Nuclear and Particle
Physic
Differential and Common Mode Noise Waves and Correlation Matrices
This paper presents an innovative extension of the noise wave definition to mixed mode, differential – and common-mode noise waves which can be used for noise analysis of differential microwave networks. Mixed mode noise waves are used next to define generalized mixed mode noise wave correlation matrices of microwave multiport networks. Presented approach may be used for noise analysis of microwave differential networks with differential ports as well as with conventional single ended ports
Waterfowl and their role in lake ecosystems. [Translation from: Wiadomosci Ekologiczne 19, 355-371, 1973.]
We know very little about the role of birds in different ecosystems, despite numerous interesting works of researchers and amateur ornithologist scattered throughout the world. Less attention is paid to freshwater ecosystems because of the difficulties encountered in the experimental methods as well as a lack of interest on behalf of hydrobiologists, for the activities of birds in these ecosystems. This article summarises types and morphoecological forms of waterfowl and their place in the lake ecosystem
Analysis of nonconstant area combustion and mixing in ramjet and rocket-ramjet hybrid engines
One-dimensional analysis of variable area mixing and combustion process in supersonic ramjet and rocket-ramjet hybrid engine
Magnetic properties of Sn/1-x/Cr/x/Te diluted magnetic semiconductors
We present the studies of Sn/1-x/Cr/x/Te semimagnetic semiconductors with
chemical composition x ranging from 0.004 to 0.012. The structural
characterization indicates that even at low average Cr-content x < ?0.012, the
aggregation into micrometer size clusters appears in our samples. The magnetic
properties are affected by the presence of clusters. In all our samples we
observe the transition into the ordered state at temperatures between 130 and
140 K. The analysis of both static and dynamic magnetic susceptibility data
indicates that the spin-glass-like state is observed in our samples. The
addition of Cr to the alloy seems to shift the spin-glass-like transition from
130 K for x = 0.004 to 140 K for x = 0.012.Comment: 4 pages, 4 figure
Fission barriers in actinides in covariant density functional theory: the role of triaxiality
Relativistic mean field theory allowing for triaxial deformations is applied
for a systematic study of fission barriers in the actinide region. Different
pairing schemes are studied in details and it is shown that covariant density
functional theory is able to describe fission barriers on a level of accuracy
comparable with non-relativistic calculations, even with the best
phenomenological macroscopic+microscopic approaches. Triaxiality in the region
of the first saddle plays a crucial role in achieving that.Comment: 11 pages, 13 figure
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