Search results for "Chemical species"

1994

Polymer blends can undergo, during processing, degradation phenomena because of the presence of both temperature and mechanical stresses. With respect to pure homogeneous polymers, the degradation of polymer blends shows distinct features because of the possible interaction between the different chemical species. These interaction can give rise to both a faster degradation or to the formation of copolymers which act as stabilizing agents. This latter phenomena is particularly important in the processing of condensation polymers

Localized surface plasmon resonance sensor based on Ag-PVA nanocomposite thin films

2009

In this work we demonstrate the use of nanocomposite thin films of poly(vinyl alcohol) with embedded silver NPs for chemosensing purposes. Silver NPs are in situ synthesized inside polyvinyl alcohol during the bake step of the formation of a nanocomposite thin film. The polymer in the nanocomposite provides an appropriate chemical and electromagnetic environment for metal NPs in order to interact with and hence detect the chemical species. A limit of detection below 20 nM is found when detecting 2-mercaptoethanol as the analyte, when measuring spectral changes (peak wavelength, linewidth and intensity) in the Localized Surface Plasmon Resonance. Potential qualitative and semi-quantitative s…

Properties of Multi Phase Interfaces on the Tungsten Trioxide Particles in the Thin Films

2000

A wide spectrum of physical and chemical properties of thin films of tungsten trioxide compounds depend on composition, constitution and structure of the film, interaction with environment, and the type of external influences/excitations. The reason is the non-stoichiometric nature of transition metal oxides and properties of d-electrons. The short range order of non-stoichiometric compounds or phases of WO3 has a strong perovskite arrangement of tungsten and oxygen ions [1, 2]. The smallest crystalline clusters of perovskite short range order consist 6÷9 of [WO6]-octahedrons. One of the structural peculiarities-features of tungsten trioxide, related to non-stoichiometry, is a variety of [W…

Experimental study of the long range interactions between a Na (3S) and a Rb (5S) atom

2005

Transitions to near asymptotic levels of the a3Σ+ and the X1Σ+ electronic states in NaRb were recorded by high resolution Fourier transform spectroscopy technique. The hyperfine splitting of the a3Σ+ state levels was analysed. The application of coupled channels calculations is discussed for determination of accurate potential energy curves of the a3Σ+ and the X1Σ+ states capable for reliable description of cold collisions between a Na and a Rb atoms in their ground states.

The enrichment ratio of atomic contacts in crystals, an indicator derived from the Hirshfeld surface analysis

2014

An enrichment ratio is derived from the decomposition of the crystal contact surface between pairs of interacting chemical species. The propensity of different contact types to form is investigated.