The Optical Properties of Light Rare-Earth Metals in the Liquid State

The model of almost free electrons is used to analyze the experimentally obtained optical properties of liquid light rare-earth metals (REM) such as lanthanum, cerium, praseodymium, and neodymium. The electrons involved in interband transitions are divided into different groups. In so doing, the contribution by these groups of electrons to the light conductivity is taken into account. The problem of determining partial values of functions is solved in a graphic representation using the method of successive approximations, by variational selection of three parameters, namely, the height of peak, its position, and half-width. It is demonstrated that, in order to explain the experimentally obtained dispersion curves of light conductivity of liquid lanthanum and cerium, it is sufficient to divide the electrons involved in interband transitions into no more than eight groups and, in the case of praseodymium and neodymium, into no more than nine groups. The electron characteristics of these groups of excited states are given.     

Thermophysical properties of a multilayer capacitor dielectric under vacuum

Results are presented of an experimental investigation of the coefficient of thermal conductivity in a multilayer cellulose capacitor dielectric under vacuum conditions.     

Sorption of cesium on finely dispersed composite ferrocyanide sorbents

Sorption of microamounts of cesium on finely dispersed composite ferrocyanide sorbents was studied. The sorbents were prepared by precipitation of nickel potassium ferrocyanide in the presence of various mineral supports (chalk, wollastonite, bentonite, clinoptilolite, diatomite, biosilica). The distribution coefficient (K _d) of ¹³⁷Cs on composite ferrocyanide sorbents is considerably higher than on nickel potassium ferrocyanide without support. The K _d values on the composite sorbents increase by a factor of 25–110 when separating the solid phase with a paper filter and by a factor of 4.3–8.2 when using a microfiltration membrane. Considerable increase in K _d of ¹³⁷Cs on composite sorbents is attributed to the formation of a nickel potassium ferrocyanide phase firmly fixed on the support surface and resistant to peptization. Composite ferrocyanide sorbents were tested for the ¹³⁷Cs recovery from a simulated NPP bottom residue in the pH range 8.5–12.0. On the composite sorbents, K _d of ¹³⁷Cs is 2.5–3.0 times higher than on the nickel ferrocyanide precipitate throughout the examined pH range. The composite sorbent based on biosilica and nickel potassium ferrocyanide was tested for treatment of real liquid radioactive waste with a total salt content of 22.0 g dm⁻³ to remove ¹³⁷Cs. The decontamination factor as high as 5190 was attained owing to simultaneous use of the finely dispersed composite ferrocyanide sorbent and an ultrafiltration ceramic membrane.