245 research outputs found
CEM03 and LAQGSM03 - new modeling tools for nuclear applications
An improved version of the Cascade-Exciton Model (CEM) of nuclear reactions
realized in the code CEM2k and the Los Alamos version of the Quark-Gluon String
Model (LAQGSM) have been developed recently at LANL to describe reactions
induced by particles and nuclei for a number of applications. Our CEM2k and
LAQGSM merged with the GEM2 evaporation/fission code by Furihata have
predictive powers comparable to other modern codes and describe many reactions
better than other codes; therefore both our codes can be used as reliable event
generators in transport codes for applications. During the last year, we have
made a significant improvements to the intranuclear cascade parts of CEM2k and
LAQGSM, and have extended LAQGSM to describe photonuclear reactions at energies
to 10 GeV and higher. We have produced in this way improved versions of our
codes, CEM03.01 and LAQGSM03.01. We present a brief description of our codes
and show illustrative results obtained with CEM03.01 and LAQGSM03.01 for
different reactions compared with predictions by other models, as well as
examples of using our codes as modeling tools for nuclear applications.Comment: 12 pages, 10 figures, to be published in Journal of Physics:
Conference Series: Proc. Europhysics Conf. on New Trends in Nuclear Physics
Applications and Technologies (NPDC19), Pavia, Italy, September 5-9, 200
High magnetic fields thermodynamics of heavy fermion metal YbRh2Si2
We perform comprehensive theoretical analysis of high magnetic field behavior
of the heavy-fermion (HF) compound YbRh2Si2. At low magnetic fields B, YbRh2Si2
has a quantum critical point related to the suppression of antiferromagnetic
ordering at a critical magnetic field. Our calculations of the thermodynamic
properties of YbRh2Si2 in wide magnetic field range allow us to straddle a
possible metamagnetic transition region and probe the properties of both
low-field HF liquid and high-field fully polarized one. Namely, high magnetic
fields B\sim B^*\sim 10 T fully polarize corresponding quasiparticle band
generating Landau Fermi liquid (LFL) state and suppressing HF (actually NFL)
one, while at elevating temperatures both HF state and corresponding NFL
properties are restored. Our calculations are in good agreement with
experimental facts and show that the fermion condensation quantum phase
transition is indeed responsible for the observed NFL behavior and
quasiparticles survive both high temperatures and high magnetic fields.Comment: 6 pages, 7 figure
Violent solar events of October-November 2003 as recorded by IZMIRAN radio observations
The extreme solar activity of October-November 2003 was recorded at IZMIRAN with digital radiospectrographs at 25-270 MHz and fixed-frequency radiometers at 169, 204 and 3000 MHz. An outstanding metre-wavelength noise storm took place during the fist passage of the grandiose evolving active complex across the disc which testifies to permanent electron acceleration over the complex with energy of up to tens of kiloelectronvolts. Against this background, intense metric and microwave radio bursts were recorded in association with several outstanding flare and huge coronal mass ejection (CME) events. The dynamic spectra of these events display multiband and sometimes fine-structure type II bursts, initiated by coronal shocks, and various continuum emissions. In some cases, a corresponding microwave burst at 3000 MHz includes not only an impulsive component coinciding with a flare maximum but also a predominating delayed long-duration component with a smooth time profile. The latter component is thought to be linked with a post-eruptive energy release and particle acceleration when the magnetic field, strongly disturbed by a CME, relaxes to a new quasi-equilibrium configuration via reconnection in high coronal levels
\b{eta}-delayed three-proton decay of 31Ar
The beta decay of 31Ar, produced by fragmentation of a 36Ar beam at 880
MeV/nucleon, was investigated. Identified ions of 31Ar were stopped in a
gaseous time projection chamber with optical readout allowing to record decay
events with emission of protons. In addition to \b{eta}-delayed emission of one
and two protons we have clearly observed the beta-delayed three-proton branch.
The branching ratio for this channel in 31Ar is found to be 0.07(2)%.Comment: 5 pages, 3 figures, submitted to Physical Rev.
Problems of semiotics of diseases of the Achilles tendon in clinical and educational aspects
Achilles tendon disorders are represented by a big group of heterogenous in etiology and pathogenesis conditions, that are quite frequent in patients of various age groups. The diversity of this group of orthopedic disorders and the insufficient information provided on this topic in specialized literature leads to confusion in terminology, which, in turn, leads to misunderstanding the essence of patient’s problem and to mistakes in treatment of such patients.We carried out a content-analysis of contemporary Russian and foreign literature to summarize the existing knowledge and to create the universal nomenclature of the studied pathological conditions for further correct understanding of the problem and creation of classification of disorders and injuries of Achilles tendon
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Large-scale dynamics of the mesosphere and lower thermosphere: an analysis using the extended Canadian Middle Atmosphere Model
The extended Canadian Middle Atmosphere Model is used to investigate the large-scale dynamics of the mesosphere and lower thermosphere (MLT). It is shown that the 4-day wave is substantially amplified in southern polar winter in the presence of instabilities arising from strong vertical shears in the MLT zonal mean zonal winds brought about by parameterized nonorographic gravity wave drag. A weaker 4-day wave in northern polar winter is attributed to the weaker wind shears that result from weaker parameterized wave drag. The 2-day wave also exhibits a strong dependence on zonal wind shears, in agreement with previous modeling studies. In the equatorial upper mesosphere, the migrating diurnal tide provides most of the resolved westward wave forcing, which varies semiannually in conjunction with the tide itself; resolved forcing by eastward traveling disturbances is dominated by smaller scales. Nonmigrating tides and other planetary-scale waves play only a minor role in the zonal mean zonal momentum budget in the tropics at these heights. Resolved waves are shown to play a significant role in the zonal mean meridional momentum budget in the MLT, impacting significantly on gradient wind balance. Balance fails at low latitudes as a result of a strong Reynolds stress associated with the migrating diurnal tide, an effect which is most pronounced at equinox when the tide is strongest. Resolved and parameterized waves account for most of the imbalance at higher latitudes in summer. This results in the gradient wind underestimating the actual eastward wind reversal by up to 40%
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