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Human-centred design: An emergent conceptual model
(Human-centred design: an emergent conceptual module by Zhang T and Dong H)
Understanding human needs and how design responds to human needs are essential for human-centred design (HCD). By combining Maslow’s hierarchy of needs model and Küthe’s “design and society” model, this paper proposes a conceptual model of human-centred design which marries psychology and sociology in investigating the relationship between design and human needs. The study reveals a tendency that design evolution responds to the hierarchy of human needs. Nowadays design tends to care for more levels of human needs
Comment on "Potential Energy Landscape for Hot Electrons in Periodically Nanostructured Graphene"
In a recent letter [Phys. Rev. Lett. 105 (2010) 036804] the unoccupied
electronic states of single layers of graphene on ruthenium are investigated.
Here we comment on the interpretation, which deviates in four points from [J.
Phys.: Condens. Matter 22 (2010) 302001] and outline the corresponding
consequences
Ergodicity and Mixing in Quantum Dynamics
After a brief historical review of ergodicity and mixing in dynamics,
particularly in quantum dynamics, we introduce definitions of quantum
ergodicity and mixing using the structure of the system's energy levels and
spacings. Our definitions are consistent with usual understanding of ergodicity
and mixing. Two parameters concerning the degeneracy in energy levels and
spacings are introduced. They are computed for right triangular billiards and
the results indicate a very close relation between quantum ergodicity (mixing)
and quantum chaos. At the end, we argue that, besides ergodicity and mixing,
there may exist a third class of quantum dynamics which is characterized by a
maximized entropy.Comment: 10 pages, 6 figures and 1 tabl
NLTE study of scandium in the Sun
We investigate the formation of neutral and singly ionized scandium lines in
the solar photospheres. The research is aimed derive solar (Sc) values for scandium lines, which will later be used in
differential abundance analyses of metal-poor stars. Extensive statistical
equilibrium calculations were carried out for a model atom, which comprises 92
terms for \ion{Sc}{i} and 79 for \ion{Sc}{ii}. Photoionization cross-sections
are assumed to be hydrogenic. Synthetic line profiles calculated from the level
populations according to the NLTE departure coefficients were compared with the
observed solar spectral atlas. Hyperfine structure (HFS) broadening is taken
into account. The statistical equilibrium of scandium is dominated by a strong
underpopulation of \ion{Sc}{i} caused by missing strong lines. It is nearly
unaffected by the variation in interaction parameters and only marginally
sensitive to the choice of the solar atmospheric model. Abundance
determinations using the ODF model lead to a solar Sc abundance of between
and 3.13, depending on the choice of values.
The long known difference between photospheric and meteoritic scandium
abundances is confirmed for the experimental -values.Comment: 10 pages, 6 figures, A&A accepte
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