New nanoporous biocarbons with iron and silicon impurities: Synthesis,properties, and application to supercapacitors

The problem of coupling the porous structure of carbon materials with their electronic structure to achieve the maximum efficient operation of an electric double layer, i.e., the interfaces with the electrolyte, was considered. The initial materials for producing activated carbon were flax and field horsetail fibers. The effect of introducing iron-containing impurities into the initial raw flax material and natural silicon in the horsetail structure on the parameters of capacitive energy storage was studied. The investigation of the capacitance-voltage characteristics of the electric double layer, magnetic properties, and Raman spectroscopy data made it possible to propose a mechanism explaining the data obtained.     

On quadratic forms

The present paper is related to the Jordan—von Neumann characterization of inner product spaces, to the Halperin problem concerning quadratic forms, to some results of the present author on quadratic and sesquilinear forms and to recently obtained results of C. T. Ng and of J. Vukman.Dedicated to Professor Otto Haupt with best wishes on his 100th birthday.     

Total ionization and electron attachment cross sections of CCl2F2 by electron impact

The absolute total ionization cross sections from threshold to 250 eV and dissociative attachment cross sections from zero to 10 eV have been measured for the CCl₂F₂ (dichloro-difluoro-methane) molecule by using a parallel plate condenser type ionization chamber. The maximum of the ionization cross-section curve was found to be at an energy of about 90 eV with a cross section of 1.44 × 10^?19 m². The attachment cross-section curve shows three peaks, the most intense being at zero electron energy with a cross-section value of 1.80 × 10^?20 m², and the other two at energies of 0.6 eV and 3.5 eV, respectively. The maximal relative error in cross-section values is 0.08, for electron energies larger than 0.4 eV.