On the term “pH of the precipitation onset of heavy metal hydroxides”

It is suggested to take as pH of the precipitation onset of metal hydroxides the pH at which 10% of the initial amount of metal ions has precipitated. An equation for calculating this quantity is presented.     

Specific features of separate and joint mastication of natural and 1,4-cis-butadiene rubbers in the presence of dibenzoylaminodiphenyl disulfide

Variation of the molecular structure characteristics and properties of natural and 1,4-cis-polybutadiene rubbers (gel content, molecular weight, degree of branching of macromolecules, viscosity) in the course of their separate and joint mastication in the presence of dibenzoylaminodiphenyl sulfide as mastication accelerator or without it was studied.     

Proton–proton bremsstrahlung towards the elastic limit at 190 MeV incident beam energy

A series of nucleon–nucleon bremsstrahlung (NNγ) experiments at 190 MeV incident beam energy have been performed at KVI in order to gain more insight into the dynamics governing the bremsstrahlung reaction. After initial measurements wherein the bremsstrahlung process was studied far away from the elastic limit, a new study was used to probe the process nearer to the elastic limit by measuring at lower photon energies. Measured cross sections and analyzing powers are compared with the predictions of a microscopic model and those of two soft-photon models. The theoretical calculations overestimate the data by up to ≈30%, for some kinematics.     

Mechanism of phase transitions in the (NH4)2WO2F4 ferroelastic

Precision studies of the thermophysical properties and structure of an (NH₄)₂WO₂F₄ crystal have been performed. It was established reliably that there is a sequence of two phase transitions at T ₁ = 201 K and T ₂ = 160 K characterized by wedging out of an intermediate phase with an increase in pressure. The role of tetrahedral and octahedral ionic groups in the mechanism of the structural transitions was determined.     

Synthesis and investigation of titanium diselenide intercalated with ferrocene and cobaltocene

Single crystals and polycrystals of titanium diselenide TiSe₂ intercalated with ferrocene Fe(η⁵-C₅H₅)₂ and cobaltocene Co(η⁵-C₅H₅)₂ are synthesized. The magnetic susceptibility and electrical resistivity of the intercalation compounds are measured. The results obtained demonstrate that the intercalation brings about the formation of an impurity band with a temperature-dependent width.     

Investigation into the dielectric relaxation of vinylidene fluoride copolymers with hexafluoropropylene

Four relaxation processes and one ferroelectric-paraelectric phase transition are revealed in vinylidene fluoride-hexafluoropropylene copolymers with different ratios of the components in the temperature range from ?100 to 150°C. The relaxation process occurring at the lowest temperature is associated with the local mobility of the chains, whereas the relaxation process at a higher temperature is due to micro-Brownian motion of segments in the amorphous phase in the glass transition range. A smeared relaxor phase transition from the polar modification of the α phase of vinylidene fluoride units to the paraelectric phase is observed in the temperature range 50–70°C. At higher temperatures, there occurs an intensive relaxation process that can be attributed to space-charge relaxation or manifestation of the normal relaxation mode.