8,034 research outputs found
The Dyer-Roeder relation in a universe with particle production
We have obtained analytical exact solutions of the Dyer-Roeder equation in a
cosmological model where creation of particles occurs at the expenses of the
gravitational field. We discussed the influences of inhomogeneities in the path
of a light beam on the apparent diameter of astrophysical objects and consider
both redshift independent as redshift dependent distributions of the
inhomogeneities.Comment: 7 pages, 4 figures. Accepted to be published in the Astronomy and
Astrophysics Journa
Tratamento e reciclagem de águas residuárias em sistema intensivo de produção de leite.
bitstream/item/65245/1/CT-75-Tratamento-e-reciclagem-de-aguas.pd
Topological insulator particles as optically induced oscillators: towards dynamical force measurements and optical rheology
We report the first experimental study upon the optical trapping and
manipulation of topological insulator (TI) particles. By virtue of the unique
TI properties, which have a conducting surface and an insulating bulk, the
particles present a peculiar behaviour in the presence of a single laser beam
optical tweezers: they oscillate in a plane perpendicular to the direction of
the laser propagation, as a result of the competition between radiation
pressure and gradient forces. In other words, TI particles behave as optically
induced oscillators, allowing dynamical measurements with unprecedented
simplicity and purely optical control. Actually, optical rheology of soft
matter interfaces and biological membranes, as well as dynamical force
measurements in macromolecules and biopolymers, may be quoted as feasible
possibilities for the near future.Comment: 6 pages, 5 figures. Correspondence and requests for Supplementary
Material should be addressed to [email protected]
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