1,376 research outputs found
Gold in graphene: in-plane adsorption and diffusion
We study the bonding and diffusion of Au in graphene vacancies using
density-functional theory. Energetics show that Au adsorbs preferably to double
vacancies, steadily in-plane with graphene. All diffusion barriers for the
complex of Au in double vacancy are above 4 eV, whereas the barriers for larger
vacancies are below 2 eV. Our results support the main results of a recent
experiment [Gan et al., Small 4, 587 (2008)], but suggest that the observed
diffusion mechanism is not thermally activated, but radiation-enhanced.Comment: 3 pages, 3 figure
Prevalence of tail biting in pigs and associations to carcass condemnations - a Finnish pilot study
The aim of this study was to investigate the prevalence of tail biting in Finland and the relationship between tail biting and carcass condemnation
Comparison of Raman spectra and vibrational density of states between graphene nanoribbons with different edges
Vibrational properties of graphene nanoribbons are examined with density
functional based tight-binding method and non-resonant bond polarization
theory. We show that the recently discovered reconstructed zigzag edge can be
identified from the emergence of high-energy vibrational mode due to strong
triple bonds at the edges. This mode is visible also in the Raman spectrum.
Total vibrational density of states of the reconstructed zigzag edge is
observed to resemble the vibrational density of states of armchair, rather than
zigzag, graphene nanoribbon. Edge-related vibrational states increase in energy
which corroborates increased ridigity of the reconstructed zigzag edge.Comment: 4 pages, 4 figure
Electronic-structure-induced deformations of liquid metal clusters
Ab initio molecular dynamics is used to study deformations of sodium clusters
at temperatures K. Open-shell Na cluster has two shape
isomers, prolate and oblate, in the liquid state. The deformation is stabilized
by opening a gap at the Fermi level. The closed-shell Na remains magic also
at the liquid state.Comment: REVTex, 11 pages, no figures, figures (2) available upon request
(e-mail to hakkinen at jyfl.jyu.fi), submitted to Phys. Rev.
Stability of conductance oscillations in monatomic sodium wires
We study the stability of conductance oscillations in monatomic sodium wires
with respect to structural variations. The geometry, the electronic structure
and the electronic potential of sodium wires suspended between two sodium
electrodes are obtained from self-consistent density functional theory
calculations. The conductance is calculated within the framework of the
Landauer-B\"utttiker formalism, using the mode-matching technique as formulated
recently in a real-space finite-difference scheme [Phys. Rev. B \textbf{70},
195402 (2004)]. We find a regular even-odd conductance oscillation as a
function of the wire length, where wires comprising an odd number of atoms have
a conductance close to the quantum unit , and even-numbered
wires have a lower conductance. The conductance of odd-numbered wires is stable
with respect to geometry changes in the wire or in the contacts between the
wire and the electrodes; the conductance of even-numbered wires is more
sensitive. Geometry changes affect the spacing and widths of the wire
resonances. In the case of odd-numbered wires the transmission is on-resonance,
and hardly affected by the resonance shapes, whereas for even-numbered wires
the transmission is off-resonance and sensitive to the resonance shapes.
Predicting the amplitude of the conductance oscillation requires a
first-principles calculation based upon a realistic structure of the wire and
the leads. A simple tight-binding model is introduced to clarify these results.Comment: 16 pages, 20 figure
Cross-Cultural Adaptation and Validation of the Finnish Version of the Michigan Hand Outcomes Questionnaire
Background and Aims: Michigan Hand Outcomes Questionnaire is a widely used patient-reported outcome measure in hand surgery. The aim of this study was to translate and validate the Michigan Hand Outcomes Questionnaire into Finnish for Finnish patients with hand problems following international standards and guidelines. Material and Methods: The original English Michigan Hand Outcomes Questionnaire was translated into Finnish. Altogether, 115 patients completed the Finnish Michigan Hand Outcomes Questionnaire, and reference outcomes: Disabilities of the Arm and Shoulder, EQ-5D 3L and pain intensity on a visual analog scale. Grip and key pinch forces were measured. After 1-2 weeks, 63 patients completed the Finnish Michigan Hand Outcomes Questionnaire the second time. The Michigan Hand Outcomes Questionnaire was analyzed for internal consistency, repeatability, correlations with the reference outcomes, and factor analysis. Results: Cronbach's alpha ranged from 0.90 to 0.97 in all the Michigan Hand Outcomes Questionnaire subscales, showing high internal consistency. The intraclass correlation coefficient showed good to excellent test-retest reliability ranging from 0.66 to 0.91 in all the Michigan Hand Outcomes Questionnaire subscales. In factor analysis, the structure with six subscales was not confirmed. All the subscales correlated with Disabilities of the Arm and Shoulder score, and five subscales correlated with EQ-5D index. Conclusion: The Finnish version of the Michigan Hand Outcomes Questionnaire showed similar properties compared to the original English version and thus can be used as patient-reported outcome measure for Finnish patients with hand problems.Peer reviewe
Close-Packing of Clusters: Application to Al_100
The lowest energy configurations of close-packed clusters up to N=110 atoms
with stacking faults are studied using the Monte Carlo method with Metropolis
algorithm. Two types of contact interactions, a pair-potential and a many-atom
interaction, are used. Enhanced stability is shown for N=12, 26, 38, 50, 59,
61, 68, 75, 79, 86, 100 and 102, of which only the sizes 38, 75, 79, 86, and
102 are pure FCC clusters, the others having stacking faults. A connection
between the model potential and density functional calculations is studied in
the case of Al_100. The density functional calculations are consistent with the
experimental fact that there exist epitaxially grown FCC clusters starting from
relatively small cluster sizes. Calculations also show that several other
close-packed motifs existwith comparable total energies.Comment: 9 pages, 7 figure
Multi-shell gold nanowires under compression
Deformation properties of multi-wall gold nanowires under compressive loading
are studied. Nanowires are simulated using a realistic many-body potential.
Simulations start from cylindrical fcc(111) structures at T=0 K. After
annealing cycles axial compression is applied on multi-shell nanowires for a
number of radii and lengths at T=300 K. Several types of deformation are found,
such as large buckling distortions and progressive crushing. Compressed
nanowires are found to recover their initial lengths and radii even after
severe structural deformations. However, in contrast to carbon nanotubes
irreversible local atomic rearrangements occur even under small compressions.Comment: 1 gif figure, 5 ps figure
- …