Barentsburg and Longyearbyen in times of socioeconomic transition: Residents' perceptions of community viability

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Ion-Conducting Flexible Thin Films of Composites from Poly(ethylene oxide) and Nematic Liquid Crystals E8—Characterization by Impedance and Dielectric Relaxation Spectroscopy

Complex electrical impedance and dielectric spectroscopy were applied to study the dielectric relaxations and their thermal behavior in ion-conducting composites/complexes from polymer poly(ethylene oxide) (PEO) and E8 nematic liquid crystals (LCs), at the compositional ratio PEO:E8 = 70:30 wt%. Flexible thin films of PEO/E8 with a thickness of 150 μm were inspected, as well as such films from Na+ ion-conducting electrolyte PEO/E8/NaIO4 with the same PEO:E8 compositional ratio, but additionally containing 10 wt.% from the salt sodium metaperiodate (NaIO4) as a dopant of Na+ ions. The molecular dynamics, namely the dielectric relaxation of PEO/E8 and PEO/E8/NaIO4, were characterized through analyses of complex impedance and dielectric spectra measured in the frequency range of 1 Hz–1 MHz, under variation of temperature from below to above the glass-transition temperature of these composites. The relaxation and polarization of dipole formations in PEO/E8 and PEO/E8/NaIO4 were evidenced and compared in terms of both electrical impedance and dielectric response depending on temperature. The results obtained for molecular organization, molecular relaxation dynamics, and electric polarization in the studied ion-conducting polymer/LC composites/complexes can be helpful in the optimization of their structure and performance, and are attractive for applications in flexible organic electronics, energy storage devices, and mechatronics

Dynamics of nanoclustering in Te+ implanted Si after application of high frequency electromagnetic field and thermal annealing

Tellurium nanoclusters were synthesized in (100) Si by ion implantation followed by annealing for 60 min with a 0.45 MHz high-frequency electromagnetic field. The results were compared with previous ones for a 30 min treatment. Structural studies were done by cross-sectional high resolution transmission electron microscopy and fast Fourier transformation of the images. The results show that for the 60 min treatment, the dynamics of nanocluster formation change, larger clusters are observed, some of which crystallized and were separated by high-resistive areas of amorphous Si. The structural changes are correlated with the electrical resistance as measured by ac impedance spectroscopy. The conductance of the samples after the 60 min treatment, compared to as implanted samples, dropped by seven orders of magnitude in the range of low frequencies and about three orders of magnitude at higher frequencies. This drastic change of the electrophysical behaviour of the field treated nanomaterial is discussed in terms of potential barriers at the interface of different phases