Two-step numerical procedure for complex permittivity retrieval of dielectric materials from reflection measurements

A two-step measurement procedure has been proposed for measurement of complex permittivity of dielectric materials using one-port reflection measurements. In the procedure, as a first step, a graphical method is applied to analyze on the complex reflection-coefficient plane the general pattern of dielectric behavior of the sample. Then, as a second step, optimization algorithms are utilized for retrieving electrical properties of samples. The procedure requires measurement of complex reflection scattering parameters of at least two samples with different lengths. It has been validated by X-band measurements of three polyvinyl chloride samples with lengths 5, 10, and 20 mm.     

Stimuli responsive release of metalic nanoparticles on semiconductor substrates

Optically active metal nanoparticles have been of recent and broad interest for applications to biomarker detection because of their ability to enable high sensitivity enhancements in various optical detection techniques. Here, we report stimuli responsive release of metallic nanoparticles on a semiconductor thin film array structure based on pH change. The metallic nanoparticles are obtained by a simple redox procedure on the semiconductor surface. This approach allows controlling nanoparticle surface coatings in situ for biomolecule conjugation, such as DNA probes on nanoparticles, and rapid stimuli responsive release of these nanoparticles upon pH change.     

Photoluminescence properties of multilayer oxide films intercalated with rare earth ions by the layer-by-layer technique

Multilayer oxide films consisting of a TiO-Eu3+-TiO-Tb3+-NbO-Tb3+-NbO-Eu3+ unit which was prepared by the layer-by-layer technique, showed photoluminescence with a high intensity containing both red and green lights.     

Canonical equilibrium distribution derived from Helmholtz potential

Plastino and Curado [A. Plastino, E.M.F. Curado, Phys. Rev. E 72 (2005) 047103] recently determined the equilibrium probability distribution for the canonical ensemble using only phenomenological thermodynamical laws as an alternative to the entropy maximization procedure of Jaynes. In the current paper we present another alternative derivation of the canonical equilibrium probability distribution, which is based on the definition of the Helmholtz free energy (and its being constant at the equilibrium) and the assumption of the uniqueness of the equilibrium probability distribution. Noting that this particular derivation is applicable for all trace-form entropies, we also apply it to the Tsallis entropy, showing that the Tsallis entropy yields genuine inverse power laws.