Diatoms of sediments of plescheevo lake (Russia) as indicators of environmental changes in holocene and anthropogenic causes. The 
core of the bottom sediments selected from Pleshcheyevo Lake (Russia). The maximum age
 Diatoms in bottom sediments of the arctic lake in the pechora river delta (Nenets Autonomous Okrug, Russia). The results of the diatom analysis of a 96 cm long continuous sediment 
core from the artic lake in the Pechora
 Mechanochemical reaction in graphane under uniaxial tension peculiarities that accompany the deformation-failure-rupture process occurred in the 
body. A comparative study