Relativistic Study on the Scattering of e± from Atoms and Ions of the Rn Isonuclear Series

Calculations are presented for differential, integrated elastic, momentum transfer, viscosity, inelastic, total cross sections and spin polarization parameters S, T and U for electrons and positrons scattering from atoms and ions of radon isonuclear series in the energy range from 1 eV–1 MeV. In addition, we analyze systematically the details of the critical minima in the elastic differential cross sections along with the positions of the corresponding maximum polarization points in the Sherman function for the aforesaid scattering systems. Coulomb glory is investigated across the ionic series. A short range complex optical potential, comprising static, polarization and exchange (for electron projectile) potentials, is used to describe the scattering from neutral atom. This potential is supplemented by the Coulomb potential for the same purpose for a charged atom. The Dirac partial wave analysis, employing the aforesaid potential, is carried out to calculate the aforesaid scattering observables. A comparison of our results with other theoretical findings shows a reasonable agreement over the studied energy range.

Investigating the Corrosion Behaviour of Corrosion Resistant Alloys in Solutions Containing Dilute Fluoride

The ability of fluoride ions, in trace concentrations, to promote film instability and transpassive dissolution was shown for several corrosion resistant alloys. While the addition of fluoride ion was found to decrease the transpassive dissolution potential by approximately 0.1 V, the decrease was particularly pronounced in mildly acidic media (pH 5). Results suggest that the decreased potential range of stability for the heavily-relied-upon Cr(III)-rich oxide film is a concern in the presence of oxidizing impurities which may push the corrosion potentials toward the transpassive region. The decreased potential range of passive film stability was observed using both dynamic and static polarization experiments and supported by solution and surface analyses.

Hysteresis-Free Piezoresponse in Thermally Strained Ferroelectric Barium Titanate Films

Modern technology asks for thin films of sustainable piezoelectrics, whereas electro-mechanical properties of such films are poorly explored and controlled. Here, dynamic and quasi-static polarization, dielectric, and piezoelectric responses were experimentally studied in thin-film stacks of barium titanate sandwiched between electrodes and grown on top of strontium titanate substrate. Accurate piezoelectric characterization was secured by using double beam interferometric technique. All out-of-plane responses were found to be hysteresis-free. Effective piezoelectric coefficient ~50 pm/V and linear strain-voltage characteristic were achieved. The observed behavior was ascribed to field induced out-of-plane polarization, whereas spontaneous polarization is in-plane due to in-plane tensile thermal strain. Hysteresis-free linear piezoresponse was anticipated in thin films on commercial silicon substrates, enabling large thermal strain.

THEORETICAL MODEL AND DESIGN OF A NOVEL STATIC POLARIZATION WIND IMAGING INTERFEROMETER (NSPWII)

Polarization array based polarization Michelson wind field detection interferometer is a new type of interferometer for detecting atmospheric temperature and wind field velocity. We proposed a theoretical model and design of the novel static polarization wind imaging interferometer (NSPWII). It consists of a group of polarizers and waveplates, a polarization beamsplitter, a field widened Michelson interferometer, a pyramid prism, and a polarization array. Based on the principle of polarization interference, a polarization array composed of four polarizers with 45° polarization directions differences is directly in front of the detector, and four modulated light beams from the pyramid prism pass through the four polarizers. Then, interferograms with four different intensity are imaged on the detector simultaneously, which further provides the atmospheric temperature and wind field velocity. The advantages of this instrument are static (no moving parts), achromatic, and temperature compensated. It is capable of measuring the upper atmospheric wind field in real time with a high precision.