Molecular orientation in electrodeposited polypyrrole films

The molecular arrangement in electrodeposited polypyrrole films was studied by means of linear dichroism in the near-edge X-ray absorption fine structure (NEXAFS) spectra measured at the K absorption edges of carbon and nitrogen. It has been found that the change of the exciting radiation incidence from normal to grazing leads to an increase in the intensity of π*-related resonances with simultaneous decrease in the intensity of σ*-related resonances in the spectra. Similar changes in the spectra measured for both absorption edges indicate a pronounced conjugation of π-bonds in the polypyrrole chains in the grown films. Preferential in-plane orientation of pyrrole rings relative to the substrate surface is observed for all the deposited films. The linear dichroism is more pronounced at the initial stages of deposition (2D growth) than at later stages characterized by “cauliflower”-like morphology of the grown film.     

On the vibrations described by the telegraph equation in the case of a system consisting of several parts of different densities and elasticities

We consider mixed initial-boundary value problems for longitudinal vibrations described by the telegraph equation in the case of a system consisting of several parts with different densities and elasticities but with equal impedances. We consider the cases of control by displacements at both endpoints of the rod, by elastic forces at both endpoints, and by an elastic force at one endpoint and a displacement at the other endpoint. We find closed-form expressions for the solutions of these mixed problems.     

Time-projection chamber for the PEN experiment

The PEN collaboration carries out a precision measurement of the ??⁺ ?? e ⁺?? decay branching ratio at the Paul Scherrer Institute (PSI, Switzerland). A special mini time-projection chamber (mTPC) has been developed for registration of particles in the pion beam. The chamber contains 14 × 10^?3 g/cm² of matter on the particle path. The chamber was successfully used during one-year-long run. Design and characteristics of the mTPC are described.     

Synthesis and electrophysical characteristics of VO2-based nanostructures with a complicated architecture on a silicon surface

Nanofilms of complicated architecture based on VO₂ and containing chromium were synthesized by the molecular layering method. The study of electrophysical characteristics of vanadium dioxide nanocrystallites and of VO₂-containing chromium has shown that semiconductor-metal phase transitions appear in the ranges of 130–160 and 100–110 K, respectively. The introduction of a transition-element ion in the nanostructures based on VO₂ affects the phase transition characteristics.     

The Use of IR Spectroscopy and Density Functional Theory for Estimating the Relative Concentration of Triglycerides of Oleic and Linoleic Acids in a Mixture of Olive and Sunflower Seed Oils

Optics and Spectroscopy - Infrared spectra of five samples of sunflower seed oil and five samples of cold-pressed olive oil of different brands are recorded in the range of 650–3800...     

Formation of Free Electrons in Collisions of Xe Atoms with α Particles

Technical Physics - We have measured the cross sections of elementary processes occurring during collisions of impinging 3He2+ particles with kinetic energies in the range 1–100 keV with Xe...