Selective photorefractive scattering in LiNbO<Subscript>3</Subscript>:Rh crystals

Photorefractive scattering occurs in rhodium-doped lithium niobate crystals irradiated by coherent light. The photorefractive scattering has both wide-angle and selective components. The results of experimental investigation of selective photorefractive scattering in LiNbO₃:Rh crystals and calculation of the spatial structure of scattering are reported. The selective scattering is regarded as a kind of a frequency-degenerate fourwave vector interaction.     

Adhesion of protective coatings with modified filler

The effect of physical (ultrasonic) and chemical (exposure in 3% solution of acetic acid) activation of filler on the adhesion strength of the protective coatings based on styrene–acrylic dispersions to different substrates is studied. It is shown that modification of kaolins allows one to increase the adhesion strength by 40–50% in the case of the physical activation and by 1.1–1.2 times in the case of chemical activation. The best results are achieved with the use of E-21 dispersion as the polymer matrix.     

Study of the processes of epoxyallyl polymer formation of IPN type upon curing of oligomer-oligomer mixtures

The process of epoxyallyl polymer formation upon curing of oligomers, proceeding simultaneously in independent directions, was studied. A significant mutual influence of epoxy and allyl groups on the level of transformation was established.     

Epoxyallyl polymers: Preparation,structure, and properties

Ways to prepare epoxyallyl polymers with a structure of interpenetrating networks (IPNs) were considered. It was shown that the constructability and high adhesive and cohesive characteristics of obtained polymers evoke interest in the practicality of curing and structuring study for epoxyallyl IPNs and the properties of materials based on them.     

Epoxy-amine polymers obtained upon curing with adamantane diamines

The versions of modification of epoxy polymers upon curing of epoxy-diane oligomers with adamantane diamines and adamantane-containing imidazolines that are close in basicity to aliphatic amines are considered. The parameters of their manufacturability, life and curing times, and parameters that characterize the adhesion strength are defined. The effect of an increase in the functionality of epoxy compounds on the thermal stability of epoxy adamantane-containing polymers is established.     

An investigation of the interconnection between topological characteristics of physical and chemical networks of anhydride adamantane-containing epoxy polymers

The interconnection between topological characteristics of chemical and physical networks of adamantane-containing epoxy polymers of anhydride curing is studied. It is shown that the introduction of adamantane fragments into the network of an epoxy polymer by different methods affects the glass-transition point and stress-strain properties. The changes in polymer properties depending on the concentration of modifying agents are analyzed during comparison of the frequency parameters of the networks of chemical bonds and engagements within a cluster model of the structure of the polymer amorphous state.     

Orientationally polarized dependence of image contrast in doped lithium niobate crystals

In lithium niobate crystals doped with photorefractive iron and copper admixtures when lightening objects with broadband incoherent radiation one can observe typical orientation and polarized dependences of image contrast. The record does not realize at orientation of light bands in the image parallel to the polar axis of the crystal.     

Measurements of the mean temperature and velocity motion of clouds by the remote sensing method at millimeter wavelength

Measurements of the cloudiness atmosphere brightness temperature in zenith at 4.3 and 8.2 mm wavelengths permit one to find the projection of the cloud velocity, the direction of the cloud motion and the mean temperature of the cloud.