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141.
Szabolcs Osváth Nóra Vajda Zsuzsa Molnár Éva Kovács-Széles Mihály Braun Máté Halász 《Journal of Radioanalytical and Nuclear Chemistry》2017,314(1):31-38
A radioanalytical method (based on separation using UTEVA columns and ICP-MS measurement) has been used for determination of 93Zr in 37 nuclear power plant samples. As 93Nb might affect the detection of 93Zr, Monte Carlo activation model was used to calculate the expected 93Zr/natZr mass ratio, which was compared to measured ones. It was found, that a decontamination factor of 103 is sufficient to get a measurement uncertainty of less than 10%. 相似文献
142.
This paper presents an experimental and numerical investigation on the natural convection flow in a cylindrical model hydrothermal
reactor. The flow is visualized non-intrusively and simulated with a conjugate computational model. Results show that the
flow structure consists of wall layers and core flows. In the lower half, the flows are steady due to the porous media. The
three-dimensional unsteady upper core flow is driven by the streams originated from the wall layer collision. The thermal
condition in the upper half core region is mainly determined by the total heat flow rate specified on the lower sidewall;
while the variations of porous media parameters, in the normal range for hydrothermal crystal growth process, have minor effects. 相似文献
143.
Dr. H. Braun 《Rheologica Acta》1991,30(6):523-529
Using a power-law ansatz for the temperature dependence of the shear modulus on the level of internal variables, the thermorheological behavior is modeled for viscoelastic fluids of a special group of rheological constitutive equations (rate-type models). The model parameter introduced characterizes thermoelastic contributions. The relation between the model parameter and the physical quantities appearing in deformation processes is discussed. Based on the chosen temperature dependence of the shear modulus, thermodynamically consistent equations like the nonlinear rheological constitutive equation and the temperature equation are derived. The special cases of entirely entropy and energy elastic fluids are also considered. The thermorheological behavior (exo-, - or endothermal processes) of a viscoelastic fluid in a stress-growth experiment followed by relaxation is analyzed with respect to the model parameter. 相似文献
144.
A poorly understood step in the transition from a chemical to a biological world is the emergence of self-replicating molecular systems. We study how a precursor for such a replicator might arise in a hydrothermal RNA reactor, which accumulates longer sequences from unbiased monomer influx and random ligation. In the reactor, intra- and intermolecular base pairing locally protects from random cleavage. By analyzing stochastic simulations, we find temporal sequence correlations that constitute a signature of information transmission, weaker but of the same form as in a true replicator. 相似文献
145.
M. A. Braun L. N. Lipatov M. Yu. Salykin M. I. Vyazovsky 《The European Physical Journal C - Particles and Fields》2011,71(5):1639
Application of the effective action formalism is studied for processes in which the reggeons may split. It is shown that the
gluon production on two centers is described by the contribution of the Reggeon-to-two-Reggeons-plus-Particle vertex supplemented
by certain singular contributions from the double gluon exchange. The rules for longitudinal integrations are established
from the comparison to perturbative QCD amplitude. Convenient expressions for application to the inclusive gluon production
are derived. 相似文献
146.
A new computational method for solving the nucleon?Cdeuteron breakup scattering problem has been applied to study the elastic nucleon?Cdeuteron scattering on the basis of the configuration-space Faddeev?CNoyes?CNoble?CMerkuriev equations. The Merkuriev?CGignoux?CLaverne approach has been generalized for arbitrary nucleon?Cnucleon potentials and with an arbitrary number of partial waves. The nucleon?Cdeuteron observables at the incident nucleon energy 3?MeV have been calculated using the charge-independent AV14 nucleon?Cnucleon potential including the Coulomb force for the proton?Cdeuteron scattering. Results have been compared with those of other authors and with experimental proton?Cdeuteron scattering data. 相似文献
147.
Johannes Braun Johannes Buchmann Ciaran Mullan Alex Wiesmaier 《Designs, Codes and Cryptography》2014,71(3):459-478
Sensitive electronic data may be required to remain confidential for long periods of time. Yet encryption under a computationally secure cryptosystem cannot provide a guarantee of long term confidentiality, due to potential advances in computing power or cryptanalysis. Long term confidentiality is ensured by information theoretically secure ciphers, but at the expense of impractical key agreement and key management. We overview known methods to alleviate these problems, whilst retaining some form of information theoretic security relevant for long term confidentiality. 相似文献
148.
Large-amplitude (10–15 Kelvin), millennial-duration warm events, the Dansgaard-Oeschger (DO) events, repeatedly occurred during
ice ages. Several hypotheses were proposed to explain the recurrence pattern of these events. For example, it was suggested
that DO events occurred in response to a combination of a random forcing (noise) and century-scale solar forcing. In the first
part of this paper, this hypothesis is reviewed in the framework of a minimum-complexity model of DO events, which assumes
that the events occurred each time a given forcing exceeds a certain threshold function. In the second part of the paper,
measures of multi-modality are used to investigate the recurrence pattern of DO events in the latest part (up to 42.000 years
before present) of the NGRIP (North Greenland Ice Core Project) and GISP2 (Greenland Ice Sheet Project 2) stable isotope (δ18O) records from Greenland. It is reported that the onset of DO events in both ice core records shows a maximum degree of multi-modality
at a recurrence time of about 1480 years. This pattern, whose statistical significance still needs to be tested in the future,
could point to a combination of solar forcing and random variability in triggering DO events. 相似文献
149.
150.
I. Di Marco J. Minár J. Braun M. I. Katsnelson A. Grechnev H. Ebert A. I. Lichtenstein O. Eriksson 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,72(4):473-478
We investigate the role of magnetic fluctuations in the spectral properties of paramagnetic γ-Mn. Two methods are employed.
The Local Density Approximation plus Dynamical Mean-Field Theory together with the numerically exact quantum Monte-Carlo solver
is used as a reference for the spectral properties. Then the same scheme is used with the computationally less demanding perturbative
spin-polarized fluctuation-exchange solver in combination with the Disordered Local Moment approach, and photoemission spectra
are calculated within the one-step model. It is shown that the formation of local magnetic moments in γ-Mn is very sensitive
to the value of Hund’s exchange parameter. Comparison with the experimental photoemission spectra demonstrates that γ-Mn is
a strongly correlated system, with the Hubbard band formation, which cannot be described by the perturbative approach. However,
minor change of parameters would transform it into a weakly correlated system. 相似文献