Molecular origin of enhanced proton conductivity in anhydrous ionic systems

YesIonic systems with enhanced proton conductivity are widely viewed as promising electrolytes in fuel cells and batteries. Nevertheless, a major challenge toward their commercial applications is determination of the factors controlling the fast proton hopping in anhydrous conditions. To address this issue, we have studied novel proton-conducting materials formed via a chemical reaction of lidocaine base with a series of acids characterized by a various number of proton-active sites. From ambient and high pressure experimental data, we have found that there are fundamental differences in the conducting properties of the examined salts. On the other hand, DFT calculations revealed that the internal proton hopping within the cation structure strongly affects the pathways of mobility of the charge carrier. These findings offer a fresh look on the Grotthuss-type mechanism in protic ionic glasses as well as provide new ideas for the design of anhydrous materials with exceptionally high proton conductivity

Application of dielectric spectroscopy in the dynamically changing biological system – case of <i>Neocaridina davidi</i> shrimp starvation

AbstractIn this work, dielectric studies on Neocaridina davidi shrimps have been presented. The effect of starvation on dielectric properties such as conductivity or permittivity have been shown. It was found that the onset frequency of electrode polarization depends on starvation period, which is probably related to the cytoplasm viscosity. In the dielectric spectra of shrimps two relaxation processes have been identified i.e. α and β process. The α process is probably related to the counter ion polarization while β process to the mobility of macromolecules present in the body of a shrimp, mainly to the amount of lipids. It was also found that there is a difference in dielectric response between control group and the group regenerated after 14 day starvation period. Basing on dielectric response, one can conclude that the viscosity of cytoplasm of regenerated shrimps is higher and the cells are rich in the lipid droplets when compared to control group.</jats:p

The structure and magnetic properties of rapidly quenched Fe72Ni8Nb4Si2B14 alloy

PING 2019 is organized with the support of funds for specific university research project SVK1-2019-002.In this work, the influence of heat treatment process on structure and magnetic properties for rapidly quenched Fe72Ni8Nb4Si2B14 alloy are reported. Firstly, for amorphous ribbons the onsets of crystallization process for bcc-Fe type phase (primary crystallization) and bct-Fe3B type phase (secondary crystallization) are defined by thermal analysis using heating rate of 10°C/min. Then basing on measured values the classical heat treatment process (with heating rate 10°C/min) in vacuum for wound toroidal cores is optimized to obtain best soft magnetic properties (B(H) dependencies and magnetic core loss Ps) at frequency 50 Hz. For heat treated samples the X-ray diffraction method is used to determine the unit cell parameters of bcc-Fe type nanocrystallites as well as their average crystallite size. Therefore, for optimal heat treated sample the complex magnetic permeability in the frequencies 106 -109 Hz for temperature range from -50°C to 100°C is measured and in the frequencies 104 -108 Hz at room temperature

Magnetocaloric Properties of Mn1.1Fe0.9P0.5As0.5−xGex (0 ≤ x ≤ 0.1) Compounds

Intermetallic compounds with the overall formula Mn1.1Fe0.9P0.5As0.5-xGex (x varies from 0 to 0.1) were investigated in order to study their magnetocaloric effect by monitoring the adiabatic temperature change, magnetic entropy change and their relation to structural parameters. It was found that the maximum of magnetocaloric effect was achieved for x = 0.02. Adiabatic temperature change for consolidated powder was equal to 2.75 K for the magnetic field change ΔB = 1.7 T for the sample with x = 0.02. For the pure non-doped sample, this parameter is much lower: ΔTad = 1.7 K @ ΔB = 1.7 T. This result was correlated with the change of structural parameters such as lattice constants and the unit cell volume

Effect of Co Substitution on Crystallization and Magnetic Behavior of Fe85.45−xCoxCu0.55B14 Metallic Glass

The effects of Co for Fe substitution on magnetic properties, thermal stability and crystal structure of Fe85.45−xCoxCu0.55B14 (x = 0, 2.5, 5, 7.5, 10) melt spun amorphous alloys were investigated. The Cu content was firstly optimized to minimize the energy of amorphous phase formation by the use of a thermodynamic approach. The formation of crystalline α-Fe type phase has been described using differential scanning calorimetry, X-ray diffractometry and transmission electron microscopy. The classical heat treatment process (with heating rate 10 °C/min) in vacuum for wound toroidal cores was optimized in the temperature range from 280 to 430 °C in order to obtain the best magnetic properties (magnetic saturation Bs and coercivity Hc obtained from the B(H) dependencies) at 50 Hz frequency. For optimal heat-treated samples, the complex magnetic permeability in the frequencies 104–108 Hz at room temperature was measured. Finally, magnetic core losses were obtained for 1 T/50 Hz and 1.5 T/50 Hz values for samples annealed at T = 310 °C. An analysis of transmission electron microscope images and electron diffraction patterns confirmed that high magnetic parameters are related to the coexistence of the amorphous and nanocrystalline phases.</jats:p