Search

Short range ordered (SRO) plasmonic nanohole arrays have a distinct surface plasmon polariton resonance in the visible region and exhibit an excellent sensing capability toward changes in the surrounding refractive index. While SRO and perfectly ordered plasmonic hole arrays have similar sensing properties, SRO arrays have clear advantages in fabrication, simplicity, and scalability. In this study, we use SRO gold nanoholes, which are subjected to pressure and temperature cycles, for vacuum and temperature sensing. The response of the transmission spectra to pressure changes in the range 10−3–105 Pa and temperature scans in the range 20–400 °C was recorded. Upon pressure cycling, a reversible response was observed. Upon initial temperature annealing, an irreversible blue shift in the resonance dip position was observed. Upon further temperature cycling, the resonance dip position shifts reversibly, with a notable red shift upon temperature increase. The results are discussed and interpreted based on possible molecular adsorption/desorption upon pressure cycling and in terms of the gold film's recrystallization, thermal expansion, and free electron density variations. [ABSTRACT FROM AUTHOR]

The incorporation of the probe molecule Ru(bpy)2dppz2+, where (dppz = dipyrido[3,2-a:2',3'-c]phenazine), into the perfluorinated ionomer Nafion exhibited luminescence in nonaqueous solvents but not in aqueous solvents. Steady-state emission measurements revealed a triexponential emission decay. Lifetime measurements showed that emission intensities were highly dependent on the complexity of the loading solution. These results suggest that Ru(bpy)2dppz2+ is a highly sensitive probe of Nafion.

The influence of gaseous hydrogen charging at 600 °C on the microstructure and mechanical behavior of wrought and Electron Beam Melted (EBM) Ti–6Al–4V alloys was investigated for hydrogen contents between 0.14 and 1.0 wt%. The small punch test (SPT) technique was used to characterize the mechanical behavior of all specimens. Both EBM and wrought alloys containing ∼6 wt% β and similar impurity levels showed similar phase content and mechanical property changes at all hydrogen contents, regardless of their original microstructural differences. This similarity can be explained by the high hydrogen diffusivity at the high temperature at which gaseous charging was carried out, and is in contrast to previous reports where EBM Ti–6Al–4V was found to be more sensitive to hydrogen embrittlement due to low-temperature electrochemical charging. After hydrogenation, α H and β H solid solutions were formed. The quantity of the α H phase reduced gradually with hydrogen content, while forming β H , α 2 , and hydrides. It was found that β H saturated at 0.27 wt% hydrogen content. Both alloys demonstrated relatively high strength and ductility up to hydrogen content of 0.2 wt%, i.e. below the β H saturation concentration. Above the β H saturation concentration, the mechanical properties of the maximum load (P max), deflection at maximum load (δ max), and absorbed energy (E) , degraded significantly due to hydride formation. [Display omitted] • The effects of gaseous hydrogenation on EBM and wrought Ti–6Al–4V were compared. • Both alloys had a similar phase and impurities content in the non-hydrogenated form. • Both alloys showed a similar mechanical behavior at any hydrogen content. • Above the β H saturation point, the mechanical properties degraded significantly. • Hydrogen-induced degradation is different after gaseous vs. electrochemical charging. [ABSTRACT FROM AUTHOR]