10,460 research outputs found
5d-5f Electric-multipole Transitions in Uranium Dioxide Probed by Non-resonant Inelastic X-ray Scattering
Non-resonant inelastic x ray scattering (NIXS) experiments have been
performed to probe the 5d-5f electronic transitions at the uranium O(4,5)
absorption edges in uranium dioxide. For small values of the scattering vector
q, the spectra are dominated by dipole-allowed transitions encapsulated within
the giant resonance, whereas for higher values of q the multipolar transitions
of rank 3 and 5 give rise to strong and well-defined multiplet structure in the
pre-edge region. The origin of the observed non-dipole multiplet structures is
explained on the basis of many-electron atomic spectral calculations. The
results obtained demonstrate the high potential of NIXS as a bulk-sensitive
technique for the characterization of the electronic properties of actinide
materials.Comment: Submitted to Physical Review Letters on 31 December 200
A Conceptual Framework for Servitization in Industry 4.0: Distilling Directions for Future Research
Purpose:
This paper focusses on developing further the recent conceptual frameworks of competitive dynamics and business-to-business value ecosystems considering the changing environment of Industry 4.0 and the particular perspective of servitization.
Design/Methodology/Approach:
This a conceptual paper that reviews and syntheses business model concepts in relation to competitive dynamics, collaborative business ecosystems and supply chain as evolving and reshaping manufacturing and services within Industry 4.0.
Findings:
The transformation of organizations in light of Industry 4.0 has led to a reframing of business models and practices, such as stakeholder value and supply chain relationships cooperating within a highly dynamic environment. In an attempt to consider the implications that Industry 4.0 has, particularly from the service perspective, this work attempts to distil directions for future research.
Originality/Value:
Previous studies on Industry 4.0 have articulated the reasoning about the benefits of Industry 4.0, with its paradigm shift to cyber-physical systems and revised business models. The intention of this paper, is to be able to further define collaboration and value ecosystems in order to show the interdependence and integration between organisations as applied to servitization within Industry 4.0. Moreover, this paper seeks to begin to articulate how research can be conducted to determine the degree to which the change and paradigm shift has become a reality
Probability distribution of the maximum of a smooth temporal signal
We present an approximate calculation for the distribution of the maximum of
a smooth stationary temporal signal X(t). As an application, we compute the
persistence exponent associated to the probability that the process remains
below a non-zero level M. When X(t) is a Gaussian process, our results are
expressed explicitly in terms of the two-time correlation function,
f(t)=.Comment: Final version (1 major typo corrected; better introduction). Accepted
in Phys. Rev. Let
Profile of the U 5f magnetization in U/Fe multilayers
Recent calculations, concerning the magnetism of uranium in the U/Fe
multilayer system have described the spatial dependence of the 5f polarization
that might be expected. We have used the x-ray resonant magnetic reflectivity
technique to obtain the profile of the induced uranium magnetic moment for
selected U/Fe multilayer samples. This study extends the use of x-ray magnetic
scattering for induced moment systems to the 5f actinide metals. The spatial
dependence of the U magnetization shows that the predominant fraction of the
polarization is present at the interfacial boundaries, decaying rapidly towards
the center of the uranium layer, in good agreement with predictions.Comment: 7 pages, 6 figure
Structural properties of epitaxial {\alpha}-U thin films on Ti, Zr, W and Nb
Thin layers of orthorhombic uranium ({\alpha}-U) have been grown onto
buffered sapphire substrates by d.c. magnetron sputtering, resulting in the
discovery of new epitaxial matches to Ti(00.1) and Zr(00.1) surfaces. These
systems have been characterised by X-ray diffraction and reflectivity and the
optimal deposition temperatures have been determined. More advanced structural
characterisation of the known Nb(110) and W(110) buffered {\alpha}-U systems
has also been carried out, showing that past reports of the domain structures
of the U layers are incomplete. The ability of this low symmetry structure to
form crystalline matches across a range of crystallographic templates
highlights the complexity of U metal epitaxy and points naturally toward
studies of the low temperature electronic properties of {\alpha}-U as a
function of epitaxial strain
Statistics of selectively neutral genetic variation
Random models of evolution are instrumental in extracting rates of
microscopic evolutionary mechanisms from empirical observations on genetic
variation in genome sequences. In this context it is necessary to know the
statistical properties of empirical observables (such as the local homozygosity
for instance). Previous work relies on numerical results or assumes Gaussian
approximations for the corresponding distributions. In this paper we give an
analytical derivation of the statistical properties of the local homozygosity
and other empirical observables assuming selective neutrality. We find that
such distributions can be very non-Gaussian.Comment: 4 pages, 4 figure
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