Influence of substrate on the optical properties of non-aggregated silver nanoparticles

In this paper, experimental results on the influence of the substrates of different refractive index on the optical properties of two-dimensional silver nanoparticle array are presented. It is shown that plasmon mode that arises from cooperative interactions between closely spaced nanoparticles exhibit different dependences on the incident angle of light. Those dependencies can be qualitatively explained by the concept of mirror images induced in a substrate. Semiconductor (ITO) substrate possesses higher refractive index which even more affects the optical response of silver nanoparticle array

Cancellation properties in Hall-magnetohydrodynamics with strong guide magnetic field

We present a signed measure analysis of compressible Hall-magnetohydrodynamic turbulence with an external guide field. Signed measure analysis allows to characterize the scaling behavior of the sign-oscillating flow structures and their geometrical properties (fractal dimensions of structures). A reduced numerical model, valid when a strong guide magnetic field is present, is used here. In order to discuss the effect of the Hall term, different values for the ion skin depth are considered in the simulations. Results show that as the Hall term is increased the fractal dimension of the current and vorticity sheets decreases. This observation, together with previous analysis of the same fields, provides a comprehensive description of the effect of the Hall force on the formation of structures. Two main processes are identified, namely the widening and unraveling of the sheets.Fil: Martin, Luis Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: de Vita, G.. Università della Calabria; ItaliaFil: Sorriso Valvo, L.. Centre National de la Recherche Scientifique; FranciaFil: Dmitruk, Pablo Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Nigro, G.. Università della Calabria; ItaliaFil: Primavera, L.. Università della Calabria; ItaliaFil: Carbone, V.. Università della Calabria; Itali