289 research outputs found
The Dilemmas of Tax Coordination in the Enlarged European Union
This study evaluates the economic effects of corporate tax coordination in the enlarged European Union using a computable general equilibrium model and a comprehensive set of scenarios for both a common corporate EU tax base and for full harmonisation of tax bases and tax rates. Our main findings are as follows: (i) Corporate tax coordination can yield modest aggregate welfare gains, but the details of the coordination policies determine outcomes and economic gains cannot be taken for granted. (ii) All scenarios for coordination leave some EU Member States as winners and others as losers. An agreement on tax coordination is therefore likely to require elaborate compen¬sation mechanisms. (iii) The large and diverse country effects suggest that Enhanced Cooperation for a subset of the Member States may be the most likely route towards tax coordination. Coordination among a subset of relatively homogenous Member States will lead to less radical policy changes, but also to smaller gains. (iv) Identifying winners and losers from coordination for the purpose of a compensation mechanism may be problematic, since countries experiencing gains in GDP and welfare tend to lose tax revenues, and vice versa.
Origin of the anomalous piezoelectric response in wurtzite ScAlN alloys
The origin of the anomalous, 400% increase of the piezoelectric coefficient
in ScAlN alloys is revealed. Quantum mechanical calculations show
that the effect is intrinsic. It comes from a strong change in the response of
the internal atomic coordinates to strain and pronounced softening of C
elastic constant. The underlying mechanism is the flattening of the energy
landscape due to a competition between the parent wurtzite and the so far
experimentally unknown hexagonal phases of the alloy. Our observation provides
a route for the design of materials with high piezoelectric response.Comment: 10 pages, 4 figures, accepted for publication in Phys. Rev. Let
Optical and mechanical properties of amorphous Mg-Si-O-N thin films deposited by reactive magnetron sputtering
In this work, amorphous thin films in Mg-Si-O-N system were prepared in order
to investigate the dependence of optical and mechanical properties on Mg
composition. Reactive RF magnetron co-sputtering from magnesium and silicon
targets were used for the deposition of Mg-Si-O-N thin films. Films were
deposited on float glass, silica wafers and sapphire substrates in an Ar, N2
and O2 gas mixture. X-ray photoelectron spectroscopy, atomic force microscopy,
scanning electron microscopy, spectroscopic ellipsometry, and nanoindentation
were employed to characterize the composition, surface morphology, and
properties of the films
Порівняльний аналіз зовнішньоекономічної функції Російської Федерації
Electronic-grade GaN (0001) epilayers have been grown directly on Al2O3 (0001) substrates by reactive DC-magnetron sputter epitaxy (MSE) from a liquid Ga sputtering target in an Ar/N2 atmosphere. The as-grown GaN epitaxial film exhibit low threading dislocation density on the order of ≤ 1010 cm-2 obtained by transmission electron microscopy and modified Williamson-Hall plot. X-ray rocking curve shows narrow fullwidth at half maximum (FWHM) of 1054 arcsec of the 0002 reflection. A sharp 4 K photoluminescence peak at 3.474 eV with a FWHM of 6.3 meV is attributed to intrinsic GaN band edge emission. The high structural and optical qualities indicate that MSEgrown GaN epilayers can be used for fabricating high-performance devices without the need of any buffer layer.On the day of the defence date the status of this article was: Manuscript.Original Publication:Muhammad Junaid, Ching-Lien Hsiao, Justinas Palisaitis, Jens Jensen, Per Persson, Lars Hultman and Jens Birch, Electronic-grade GaN(0001)/Al2O3(0001) grown by reactive DC-magnetron sputter epitaxy using a liquid Ga target, 2011, Applied Physics Letters, (98), 14, 141915.http://dx.doi.org/10.1063/1.3576912Copyright: American Institute of Physicshttp://www.aip.org
Effects of deposition temperature on the mechanical and structural properties of amorphous Al-Si-O thin films prepared by RF magnetron sputtering
Aluminosilicate (Al-Si-O) thin films containing up to 31 at. % Al and 23 at.
% Si were prepared by reactive RF magnetron co-sputtering. Mechanical and
structural properties were measured by indentation and specular reflectance
infrared spectroscopy at varying Si sputtering target power and substrate
temperature in the range 100 to 500 {\deg}C. It was found that an increased
substrate temperature and Al/Si ratio give denser structure and consequently
higher hardness (7.4 to 9.5 GPa) and reduced elastic modulus (85 to 93 GPa)
while at the same time lower crack resistance (2.6 to 0.9 N). The intensity of
the infrared Si-O-Si/Al asymmetric stretching vibrations shows a linear
dependence with respect to Al concentration. The Al-O-Al vibrational band (at
1050 cm-1) shifts towards higher wavenumbers with increasing Al concentration
which indicates a decrease of the bond length, evidencing denser structure and
higher residual stress, which is supported by the increased hardness. The same
Al-O-Al vibrational band (at 1050 cm-1) shifts towards lower wavenumber with
increasing substrate temperature indicating an increase in the of the average
coordination number of Al.Comment: Preprin
The Design and Implementation of an Assessment Method Combining Formative and Summative Use of Assessment
The Road I Can\u27t Help Travelling : Holmes on Truth and Persuadability
Nano-structural evolution of layer morphology and interfacial roughness in Cr/Sc metal multilayers grown with ion assistance during magnetron sputter deposition has been investigated by high resolution transmission electron microscopy and hard X-ray reflectivity. Calculations based on a binary collision model predict an ion-assisted growth window for optimized Cr/Sc multilayer interface sharpness, within the ion energy range of 21 eV to 37 eV and an ion flux of 10 ions per deposited atom. Multilayers with nominal modulation periods in the range of 1.6 nm to 10.2 nm, grown with these conditions, exhibit a well-defined layer structure with an improved flattening and abruptness of the interfaces. It is shown that multilayers with a modulation period smaller than 3.4 nm have clear benefit from the reduced intermixing obtained by utilizing a two-stage ion energy modulation for each individual layer. The amorphization of Sc and Cr layers, below certain thicknesses, is found to be independent of the low energy ion-assistance. It is also shown that the Cr/Sc multilayers, containing periods less than 2 nm are ‘self healing’ i.e. they re-gain abrupt interfaces and flat layers after morphological disturbances during ion assisted growth. In comparison, multilayers grown without ion-assistance exhibited severe roughness and layer distortions.Original publication: N. Ghafoor, F. Eriksson, P.O.Å. Persson, L. Hultman and J. Birch, Effects of ion-assisted growth on the layer definition in Cr/Sc multilayers, 2008, Thin Solid Films, (516), 6, 982-990. http://dx.doi.org/10.1016/j.tsf.2007.06.108. Copyright: Elsevier B.V., http://www.elsevier.com
Electronic structure investigation of the cubic inverse perovskite Sc3AlN
The electronic structure and chemical bonding of the recently discovered
inverse perovskite Sc3AlN, in comparison to ScN and Sc metal have been
investigated by bulk-sensitive soft x-ray emission spectroscopy. The measured
Sc L, N K, Al L1, and Al L2,3 emission spectra are compared with calculated
spectra using first principle density-functional theory including dipole
transition matrix elements. The main Sc 3d - N 2p and Sc 3d - Al 3p chemical
bond regions are identified at -4 eV and -1.4 eV below the Fermi level,
respectively. A strongly modified spectral shape of 3s states in the Al L2,3
emission from Sc3AlN in comparison to pure Al metal is found, which reflects
the Sc 3d - Al 3p hybridization observed in the Al L1 emission. The differences
between the electronic structure of Sc3AlN, ScN, and Sc metal are discussed in
relation to the change of the conductivity and elastic properties.Comment: 11 pages, 5 picture
Morphology of buried interfaces in ion-assisted magnetron sputter deposited 11B4C-containing Ni/Ti multilayer neutron optics investigated by grazing incidence small angle scattering
Multilayer neutron optics require precise control of interface morphology for
optimal performance. In this work, we investigate the effects of different
growth conditions on the interface morphology of Ni/Ti based multilayers, with
a focus on incorporating low-neutron-absorbing 11B4C and using different ion
assistance schemes. Grazing incidence small angle X-ray scattering was used to
probe the structural and morphological details of buried interfaces, revealing
that the layers become more strongly correlated and the interfaces form mounds
with increasing amounts of 11B4C. Applying high flux ion assistance during
growth can reduce mound formation but lead to interface mixing, while a high
flux modulated ion assistance scheme with an initial buffer layer grown at low
ion energy and the top layer at higher ion energy prevents intermixing. The
optimal condition was found to be adding 26.0 at.% 11B4C combined with high
flux modulated ion assistance. A multilayer with a period of 48.2 {\AA} and 100
periods was grown under these conditions, and coupled fitting to neutron and
X-ray reflectivity data revealed an average interface width of only 2.7 {\AA},
a significant improvement over the current state-of-the-art commercial Ni/Ti
multilayers. Overall, our study demonstrates that the addition of 11B4C and the
use of high flux modulated ion assistance during growth can significantly
improve the interface morphology of Ni/Ti multilayers, leading to improved
neutron optics performance.Comment: 14 page
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