Spin and orbital contributions to the magnetic moment of rhenium have been studied across the magnetostructural transition in Ca2FeReO6 double perovskite employing x-ray magnetic circular dichroism (XMCD) at the Re L2...
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Spin and orbital contributions to the magnetic moment of rhenium have been studied across the magnetostructural transition in Ca2FeReO6 double perovskite employing x-ray magnetic circular dichroism (XMCD) at the Re L2,3 edges. Temperature-dependent measurements performed in pulsed magnetic field varying from 6.8 to 30 T revealed that the two phases of this compound are characterized by a different spin-orbit coupling. At T=10 K, the average orbital-to-spin moment ratio of the Re sublattice increases in the application of 30 T magnetic field by ∼5%, while at T=250 K it is field independent and amounts to |mL/mS|=0.362(6). The field and temperature dependences of the rhenium XMCD and bulk magnetization are explained within the scenario of a field-induced phase coexistence and transition between two monoclinic phases of diverse magnetocrystalline coupling.
We elucidate the amphoteric nature of antimony as a dopant in PbTe. Band-structure calculations show that Sb substituting for Pb is a donor and that Sb on the Te site is an acceptor giving rise to a large excess densi...
We elucidate the amphoteric nature of antimony as a dopant in PbTe. Band-structure calculations show that Sb substituting for Pb is a donor and that Sb on the Te site is an acceptor giving rise to a large excess density of states (DOS). Experimentally, in Te-rich Pb1−xSbxTe samples, T125e NMR spectroscopy shows that Sb substitutes for Pb and transport data reveal that it then acts as a simple donor. In Pb-rich PbSbxTe1−x samples, T125e NMR shows that little Sb substitutes for Te when samples are prepared above 770 K and then quenched; P207b NMR shows four types of charge carriers, but only a majority hole and a minority electron contribute to transport. Sb acts as an acceptor in PbSbxTe1−x, but the large DOS calculated must correspond to a large concentration of localized holes and the Seebeck coefficient is not enhanced.
The Advanced Resource Connector (ARC) middleware introduced by NorduGrid is one of the basic Grid solutions used by scientists worldwide. While being well-proven in daily use by a wide variety of scientific applicatio...
The Advanced Resource Connector (ARC) middleware introduced by NorduGrid is one of the basic Grid solutions used by scientists worldwide. While being well-proven in daily use by a wide variety of scientific applications at large-scale infrastructures like the Nordic DataGrid Facility (NDGF) and smaller scale projects, production ARC of today is still largely based on conventional Grid technologies and custom interfaces introduced a decade ago. In order to guarantee sustainability, true cross-system portability and standards-compliance based interoperability, the ARC community undertakes a massive effort of implementing modular Web Service (WS) approach into the middleware. With support from the EU KnowARC project, new components were introduced and the existing key ARC services got extended with WS technology based standard-compliant interfaces following a service-oriented architecture. Such components include the hosting environment framework, the resource-coupled execution service, the re-engineered client library, the self-healing storage solution and the peer-to-peer information system, to name a few. Gradual introduction of these new services and client tools into the production middleware releases is carried out together with NDGF and thus ensures a smooth transition to the next generation Grid middleware. Standard interfaces and modularity of the new component design are essential for ARC contributions to the planned Universal Middleware Distribution of the European Grid Initiative.
作者：
Arbab I. ArbabDepartment of Physics
Faculty of Science University of Khartoum PO Box 321 Khartoum 11115 SudanDepartment of Physics and Applied Mathematics Faculty of Applied Sciences and Computer Omdurman Ahlia University PO Box 7S6 Omdurman Sudan
We consider a cosmological model with bulk viscosity η and variable cosmological A ∝p^-α, alpha = const and gravitational G constants. The model exhibits many interesting cosmological features. Inflation proceeds ...
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We consider a cosmological model with bulk viscosity η and variable cosmological A ∝p^-α, alpha = const and gravitational G constants. The model exhibits many interesting cosmological features. Inflation proceeds du to the presence of bulk viscosity and dark energy without requiring the equation of state p =-p. During the inflationary era the energy density p does not remain constant, as in the de-Sitter type. Moreover, the cosmological and gravitational constants increase exponentially with time, whereas the energy density and viscosity decrease exponentially with time. The rate of mass creation during inflation is found to be very huge suggesting that all matter in the universe is created during inflation.
The effect of external electric field on exchange interaction has been studied by a configuration interaction method for electrons localized in double quantum dots. We model the confinement potential by the twocenter ...
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We investigate a cosmological model of a phantom energy with a variable cosmological constant （∧） depending on the energy density （ρ） as ∧∝ρ^α,α=const and a variable gravitational constant G. The model requ...
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We investigate a cosmological model of a phantom energy with a variable cosmological constant （∧） depending on the energy density （ρ） as ∧∝ρ^α,α=const and a variable gravitational constant G. The model requires α 〈 0 and a negative gravitational constant. The cosmological constant evolves with time as ∧ ∝ t^-2. For ω 〉 - 1 and α 〈 -1 the cosmological constant ∧ 〈 0, G 〉 0 and ρ decrease with cosmic expansion. For ordinary energy （or dark energy）, i.e.ω 〉 -1, we have -1 〈 α〈 0 and β 〉 0 so that G〉0 increases with time and p decreases with time. Cosmic acceleration with dust particles is granted, provided -2/3 〈α〈 0 and ∧〉0.
The study of ADS operation and maintenance includes also the analysis of the build-up and decay of the spallation target radioactivity and heating, the heating resulting both from the beam particles and from the decay...
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ISBN:
(纸本)9781617821219
The study of ADS operation and maintenance includes also the analysis of the build-up and decay of the spallation target radioactivity and heating, the heating resulting both from the beam particles and from the decay of radioactive nuclides. The aim of the presented benchmark is the selection of the model or code most useful for the ADS calculations and, if such a tool is not yet available, the indication of the main deficiencies of the existing tools. Preliminary results of calculations and their comparison are presented.
The cluster model offers a new approach to the structure of quasicrystals. The model assumes that the whole structure can be covered by only one structure unit - the cluster. However, because quasicrystals are not per...
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The cluster model offers a new approach to the structure of quasicrystals. The model assumes that the whole structure can be covered by only one structure unit - the cluster. However, because quasicrystals are not periodic, clusters must overlap each other. The first known cluster is G33 proposed by Gummelt. Another type of cluster is the kite cluster - it is the smallest possible cluster that can cover the whole Penrose tiling. There are three different kite clusters: 17-atom K17,7-atom K7 and 4-atom K4 discussed in the paper.
The Wigner distribution function formalism is applied to the description of transport properties of spintronic multilayer nanodevice. The central layer of the nanodevice is doped with magnetic impurities. The current-...
The Wigner distribution function formalism is applied to the description of transport properties of spintronic multilayer nanodevice. The central layer of the nanodevice is doped with magnetic impurities. The current-voltage characteristics and the spin polarisation of current are calculated.
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