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991.
V. Wagner A. Krása M. Majerle F. Křížek O. Svoboda A. Kugler J. Adam V. M. Tsoupko-Sitnikov M. I. Krivopustov I. V. Zhuk W. Westmeier 《Pramana》2007,68(2):297-306
The set-up ‘energy plus transmutation’, consisting of a thick lead target and a natural uranium blanket, was irradiated by
relativistic proton beams with the energy from 0.7 GeV up to 2 GeV. Neutron field was measured in different places of this
set-up using different activation detectors. The possibilities of using the obtained data for benchmark studies are analyzed
in this paper. Uncertainties of experimental data are shown and discussed. The experimental data are compared with results
of simulation with MCNPX code.
相似文献
992.
Nathan L. Harshman 《International Journal of Theoretical Physics》2007,46(8):1929-1946
The notion that elementary systems correspond to irreducible representations of the Poincaré group is the starting point for
this paper, which then goes on to discuss how a semigroup for the time evolution of unstable states and resonances could emerge
from the underlying Poincaré symmetry. Important tools in this analysis are the Clebsch-Gordan coefficients for the Poincaré
group. 相似文献
993.
K. Jin Z. C. Wang Q. Zhang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(2):325-332
We study the absorption spectra of a degenerate V-type
atom, where a resonant driving field and a probe field drive
different branches of transitions and a dc field is applied to
drive the transition between two excited states. The effects of
vacuum induced coherence (VIC) on the absorption spectra are
investigated. It is demonstrated that in some special cases the
VIC can lead to the depression of absorption and narrow resonance.
The origin of these features are discussed. When the pump field
and the dc field have the same intensity, it is interesting to
find that the whole absorption spectrum comes mainly from the
absorptions induced by the interferences among different
transitions between dressed states. 相似文献
994.
R. Álvarez-Rodrıguez E. Garrido A. S. Jensen D. V. Fedorov H. O. U. Fynbo 《The European Physical Journal A - Hadrons and Nuclei》2007,31(3):303-317
The hyperspherical adiabatic expansion is combined with complex scaling and used to calculate low-lying nuclear resonances
of 12C in the 3α model. We use Ali-Bodmer potentials and compare results for other potentials α-α with similar 8Be properties. A three-body potential is used to adjust the 12C resonance positions to desired values extending the applicability of the method to many-body systems decaying into three
α-particles. For natural choices of three-body potentials we find 14 resonances below the proton separation threshold, i.e. two 0+, three 2+, two 4+, one of each of 1±, 2-, 3±, 4-, and 6+. The partial-wave decomposition of each resonance is calculated as a function of the hyperradius. Strong variation is found
from small to large distance. The connection to previous experimental and theoretical results is discussed and agreements
as well as disagreements are emphasized. 相似文献
995.
We investigated numerically localization properties of electron eigenstates in a chain with long-range correlated diagonal
disorder. A tight-binding one-dimensional model with
on-site energies exhibiting long-range correlated disorder (LCD)
was used with various disorder strength W. LCD was defined so
that it gave a power-law spectral density of the form S(k)αk-p, where p determines the roughness of the potential landscape. Numerical results on the correlation length ξ of
eigenstates shows the existence of the localization-delocalization transition at p=2. It is found that the critical values
for disorder strength Wc and also the critical exponent ν for
localization length change with the values of p. 相似文献
996.
L. Wu S. Zhu Y. Ni 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):349-354
Combination of two basic types of synchronization, anticipatory
synchronization and lagged synchronization, is investigated
numerically between two coupled semiconductor lasers. It is found
that lagged synchronization produced by a backward coupling with a
suitable delay can combine with the originally hidden anticipatory
synchronization and produce a type of synchronization overcoming the
original lagged synchronization produced by a forward coupling. We
study the combination synchronization phenomenon when the delay of
the backward coupling is different from that of the original
anticipatory synchronization. Our results suggest that the
synchronization combination phenomenon might allow an interpretation
of an experimental observation by Sivaprakasam et al. [Phys.
Rev. Lett. 87, 154101 (2001)] that the anticipating time is
irrespective of the external-cavity round trip time, which to date remains to be understood. 相似文献
997.
Non-Fellerian particle systems are characterized by nonlocal interactions, somewhat analogous to non-Gibbsian distributions.
They exhibit new phenomena that are unseen in standard interacting particle systems. We consider freezing transitions in one-dimensional
non-Fellerian processes which are built from the abelian sandpile additions to which in one case, spin flips are added, and
in another case, so called anti-sandpile subtractions. In the first case and as a function of the sandpile addition rate,
there is a sharp transition from a non-trivial invariant measure to the trivial invariant measure of the sandpile process.
For the combination sandpile plus anti-sandpile, there is a sharp transition from one frozen state to the other anti-state. 相似文献
998.
999.
A. K. Zhuravlev V. Yu. Irkhin M. I. Katsnelson 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(4):377-382
Using the numerical renormalization group method, the dependences on
temperature of the magnetic susceptibility χ(T) and specific heat C(T)
are obtained for the single-impurity Anderson model with inclusion of
d-f the Coulomb interaction. It is shown that the exciton effects
caused by this effect (charge fluctuations) can significantly change the
behaviour of C(T) in comparison with the standard Anderson model at
moderately low temperatures, whereas the behaviour of χ(T) remains nearly
universal. The ground-state and temperature-dependent renormalizations of the
effective hybridization parameter and f-level position caused by the
d-f interaction are calculated, and satisfactory agreement with the
Hartree-Fock approximation is derived. 相似文献
1000.
J. V. Pinto M. M. Cruz R. C. da Silva N. Franco A. Casaca E. Alves M. Godinho 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(3):253-260
The magnetic and electrical properties of Co-implanted
single crystalline TiO2 rutile are presented. For fluences of
the order of 1017 cm-2 and implantation energy of 150
keV the maximum atomic concentration of cobalt is 13 at% at a depth
of 65 nm from the surface. The as implanted single crystals exhibit
superparamagnetic behaviour attributed to the formation of nanosized
cobalt clusters. After annealing at 1073 K an anisotropic
ferromagnetic behaviour emerges with the easy magnetization axis
lying in the (001) plane of rutile. The ferromagnetic behaviour is
associated with oriented cobalt aggregates. Electrical conductivity
of the implanted samples annealed in vacuum also exhibits
anisotropic behaviour at low temperatures, but no magnetoresistive
effects were detected. 相似文献