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.
A modified method of mine tremors location used in Lubin Copper Mine is presented in the paper. In mines where an intensive exploration is carried out a high accuracy source location technique is usually required. The...
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A modified method of mine tremors location used in Lubin Copper Mine is presented in the paper. In mines where an intensive exploration is carried out a high accuracy source location technique is usually required. The effect of the flatness of the geophones array, complex geological structure of the rock mass and intense exploitation make the location results ambiguous in such mines. In the present paper an effective method of source location and location's error evaluations are presented, combining data from two different arrays of geophones. The first consists of uniaxial geophones spaced in the whole mine area. The second is installed in one of the mining panels and consists of triaxial geophones. The usage of the data obtained from triaxial geophones allows to increase the hypocenter vertical coordinate precision. The presented two-step location procedure combines standard location methods: P-waves directions and P-waves arrival times. Using computer simulations the efficiency of the created algorithm was tested. The designed algorithm is fully non-linear and was tested on the multilayered rock mass model of the Lubin Copper Mine, showing a computational better efficiency than the traditional P-wave arrival times location algorithm. In this paper we present the complete procedure that effectively solves the non-linear location problems, i.e. the mine tremor location and measurement of the error propagation. (c) 2008 Elsevier B.V. All rights reserved.
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 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.
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.
Electron tunneling through a quantum dot embedded in a nanowire was studied by the transfer matrix method. A smoothness of the interfaces was taken into account using the analytical parametrization of the potential pr...
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Electron tunneling through a quantum dot embedded in a nanowire was studied by the transfer matrix method. A smoothness of the interfaces was taken into account using the analytical parametrization of the potential profile. We calculated the current-voltage characteristics and discussed the effect of the spacer, which separates the quantum dot from the contacts. We found that the tunneling current peak possesses the asymmetric Fano resonance shape in the absence of spacer. The results of calculations agree with the experimental data.
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.
Local order is studied in Mn-doped ternary semiconductors with chalcopyrite structure. We report the Mn K-edge X-ray absorption spectra detected by the high-energy-resolution fluorescence at the manganese Kβ emission...
Local order is studied in Mn-doped ternary semiconductors with chalcopyrite structure. We report the Mn K-edge X-ray absorption spectra detected by the high-energy-resolution fluorescence at the manganese Kβ emission line. The spectra are compared with the theoretical XANES calculated for different atomic sites by the real-space multiple-scattering approach and the finite difference method. The latter approach, being a non-muffin-tin method, gives a much better match to the near-edge spectra. However, no definite Mn site assignment has been reached. Spin selective examination of the pre-edge portion of the XANES indicates 3d5 configuration of Mn in all compounds studied. On the other hand, an effective spin derived from the Kβ emission spectra is between 2 and 2.5 due to the Mn-S bond covalency.
Electron transport in the plane of a monoatomic metallic layer with non-zero magnetization is considered. The material is represented by a two-dimensional set of disordered potentials which also possess spins aligned ...
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Electron transport in the plane of a monoatomic metallic layer with non-zero magnetization is considered. The material is represented by a two-dimensional set of disordered potentials which also possess spins aligned along one axis but not necessarily oriented in one direction. Such a system can be treated as a two-component alloy. The effective cross-section for conduction electrons has been calculated. The total conductivity is obtained within two-current model.
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