2,448 research outputs found
A note on the stability for Kawahara-KdV type equations
In this paper we establish the nonlinear stability of solitary traveling-wave
solutions for the Kawahara-KdV equation and the modified Kawahara-KdV equation
where is
a positive number when . The main approach used to determine the
stability of solitary traveling-waves will be the theory developed by AlbertComment: 8 pages, no figure
Molecular dynamics simulations of reflection and adhesion behavior in Lennard-Jones cluster deposition
We conduct molecular dynamics simulations of the collision of atomic clusters
with a weakly-attractive surface. We focus on an intermediate regime, between
soft-landing and fragmentation, where the cluster undergoes deformation on
impact but remains largely intact, and will either adhere to the surface (and
possibly slide), or be reflected. We find that the outcome of the collision is
determined by the Weber number, We i.e. the ratio of the kinetic energy to the
adhesion energy, with a transition between adhesion and reflection occurring as
We passes through unity. We also identify two distinct collision regimes: in
one regime the collision is largely elastic and deformation of the cluster is
relatively small but in the second regime the deformation is large and the
adhesion energy starts to depend on the kinetic energy. If the transition
between these two regimes occurs at a similar kinetic energy to that of the
transition between reflection and adhesion, then we find that the probability
of adhesion for a cluster can be bimodal. In addition we investigate the
effects of the angle of incidence on adhesion and reflection. Finally we
compare our findings both with recent experimental results and with macroscopic
theories of particle collisions.Comment: 18 pages, 13 figure
Towards semantic software engineering environments
Software tools processing partially common set of data should share an understanding of what these data mean. Since ontologies have been used to express formally a shared understanding of information, we argue that they are a way towards Semantic SEEs. In this paper we discuss an ontology-based approach to tool integration and present ODE, an ontology-based SEE
Characterization of a defective PbWO4 crystal cut along the a-c crystallographic plane: structural assessment and a novel photoelastic stress analysis
Among scintillators, the PWO is one of the most widely used, for instance in
CMS calorimeter at CERN and PANDA project. Crystallographic structure and
chemical composition as well as residual stress condition, are indicators of
homogeneity and good quality of the crystal. In this paper, structural
characterization of a defective PbWO4 (PWO) crystal has been performed by X-ray
Diffraction (XRD), Energy Dispersive Spectroscopy (EDS) and Photoelasticity in
the unusual a-c crystallographic plane. XRD and EDS analysis have been used to
investigate crystallographic orientation and chemical composition, while stress
distribution, which indicates macroscopic inhomogeneities and defects, has been
obtained by photoelastic approaches, in Conoscopic and Sphenoscopic
configuration. Since the sample is cut along the a-c crystallographic plane, a
new method is proposed for the interpretation of the fringe pattern. The
structural analysis has detected odds from the nominal lattice dimension, which
can be attributed to the strong presence of Pb and W. A strong inhomogeneity
over the crystal sample has been revealed by the photoelastic inspection. The
results give reliability to the proposed procedure which is exploitable in
crystals with other structures.Comment: 18 pages, 10 figures, revised versio
Physical Origin of Anharmonic Dynamics in Proteins: New Insights From Resolution-Dependent Neutron Scattering on Homomeric Polypeptides
Neutron scattering reveals a complex dynamics in polypeptide chains, with two main onsets of anharmonicity whose physical origin and biological role are still debated. In this study the dynamics
of strategically selected homomeric polypeptides is investigated with elastic neutron scattering using different energy resolutions and compared with that of a real protein. Our data spotlight the dependence of
anharmonic transition temperatures and fluctuation amplitudes on energy resolution, which we quantitatively explain in terms of a two-site model for the protein-hydration water energy landscape.
Experimental data strongly suggest that the protein dynamical transition is not a mere resolution effect but is due to a real physical effect. Activation barriers and free energy values obtained for the protein
dynamical transition allow us to make a connection with the two-well interaction potential of supercooledconfined water proposed to explain a low-density -- high-density liquid-liquid transition
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