Electrochemical impedance spectroscopy and gravimetric methods were carried out to analyze water uptake of thin polyurethane films separately filled with either hydrophobic or hydrophilic nano-silica. Correspondingly the impedance spectra and gravimetric data were interpreted in terms of movement of water within the coating and/or to the coating/metal interface. Although the obtained results fr...

Tagging the environment gives users the possibility to explicitly construct and define parts of their spacial context. The tags assigned to RFIDidentified objects in the environment can be used to enrich formalized domainspecific context-models with user generated keywords to take communityand user-generated meanings into account. These references in space help to navigate information and servi...

We review several experimental methodologies for the determination of nonlinear absorption coefficients of organic chromophores in either solution or thin film form. The goal here is to also be able to identify and quantify the nonlinear absorption process or processes, e.g. the essentially instantaneous two-photon absorption (2PA) or the cumulative excited-state absorption (ESA). These methods...

Signals reflected from a randomly layered medium are nonstationary stochastic processes that can have very complicated structure. In [l, 21 we considered pulse reflection from a randomly layered half space when the pulse width is large compared to the size of the layers but small compared to the large-scale variations of the layering. Then the reflected signals have a particular structure: they...

The statistical properties of acoustic signals re ected by a randomly layered medium are analyzed when a pulsed spherical wave issuing from a point source is incident upon it. The asymptotic analysis of stochastic equations and geometrical acoustics is used to arrive at a set of transport equations that characterize multiply scattered signals observed at the surface of the layered medium. The r...

Electronic and optoelectronic properties of SiGe/Si self-assembled quantum dots are calculated by the eight-band k"p method with a revised set of parameters. The model confirms that the Si12xGex transforms to a type-II structure when x is greater than 0.25 and given accurate effective masses for Si and Ge. The polarization dependent absorption spectra show a behavior quite different from what i...

The practical usefulness of long-range acoustic measurements of ocean acidity-linked sound absorption is analyzed. There are two applications: Determining spatially-averaged pH via absorption measurement and verifying absorption effects in an area of known pH. The method is a differential-attenuation technique, with the difference taken across frequency. Measurement performance versus mean freq...

In this paper, an ultra-wideband metamaterial absorber is designed and simulated. The proposed absorber is planar and low profile. It is made of a copper sheet coated with two dielectric layers. Each unit cell of the metamaterial structure is composed of multiple metallic split rings, which are patterned on the top and middle boundaries of the dielectrics. The designed absorber utilizes differe...