8 research outputs found
Simulating radiation damage in a bcc Fe system with embedded yttria nanoparticles
We present a molecular dynamics study of radiation damage arising from nuclear collisions close to embedded yttria nanoparticles in a bcc Fe matrix. The model assumes a perfect body-centred cubic (bcc) iron matrix in which yttria nano-particles are embedded as a simplified model of an Oxide Dispersion Strengthened steel. It is shown how the nano-particles interact
with nearby initiated collision cascades, through cascade blocking and absorbing energy. Fe defects accumulate at the interface both directly from the ballistic collisions and also by attraction of defects generated close by. The nano-particles generally remain intact during a radiation event and release absorbed energy over times longer than the ballistic phase of the collision cascade
Persistence and Life Time Distribution in Coarsening Phenomen
We investigate the life time distribution in one and two dimensional
coarsening processes modelled by Ising - Glauber dynamics at zero temperature.
We find that the life time distribution obeys a scaling ansatz, asymptotically.
An independent life time model where the life times are sampled from a
distribution with power law tail is presented, which predicts analytically the
qualitative features of the scaling function.Comment: 12 pages; 6 figure
Bound Pairs: Direct Evidence for Long-range Attraction between Like-Charged Colloids
We report observations of stable bound pairs in very dilute deionized aqueous
suspensions of highly charged polystyrene colloidal particles, with monovalent
counterions, using a confocal laser scanning microscope. Through an analysis of
several thousands of time series of confocal images recorded deep inside the
bulk suspension, we find that the measured pair-potential, U(r) has a
long-range attractive component with well depths larger than the thermal
energy. These observations provide a direct and unequivocal evidence for the
existence of long-range attraction in U(r) of like-charged colloidal particles.Comment: 8 pages, 4 figures, submitted to Phys. Rev. Let
Electronic structure of Li2Pd3B and Li2Pt3B
Li2Pd3B is known to be superconducting, while the isotypical Li2Pt3B compound
is not. Electronic structures of Li2Pd3B and Li2Pt3B have been calculated in
order to obtain an insight into this surprising difference, through an analysis
of the differences in the band structures. The electronic structures of these
systems were obtained using the Full Potential Linear Augmented Plane Wave plus
local orbitals (FP-LAPW+lo) method and it was found that four bands cross the
Fermi level (EF). Out of these four bands, only two bands contribute
significantly to the density of states at the EF. One of these bands is a hole
band and the other an electron band. Thus at least a two-band model is required
for studying the electronic properties of the Pd and Pt compounds. These two
bands are rather narrow and hence the coulombic correlations effects can be
significant.Comment: 18 pages, 8 figures, submitted to Physica
Simulating radiation damage in a bcc Fe system with embedded yttria nanoparticles
This paper was accepted for publication in the journal Journal of Nuclear Materials and the definitive published version is available at http://dx.doi.org/10.1016/j.jnucmat.2013.02.016We present a molecular dynamics study of radiation damage arising from nuclear collisions close to embedded yttria nanoparticles in a bcc Fe matrix. The model assumes a perfect body-centred cubic (bcc) iron matrix in which yttria nano-particles are embedded as a simplified model of an Oxide Dispersion Strengthened steel. It is shown how the nano-particles interact
with nearby initiated collision cascades, through cascade blocking and absorbing energy. Fe defects accumulate at the interface both directly from the ballistic collisions and also by attraction of defects generated close by. The nano-particles generally remain intact during a radiation event and release absorbed energy over times longer than the ballistic phase of the collision cascade