卷 45, 编号 1 (2018)

To develop nanostructures with extremely low spatial resolution (to 10 nm and below), a new concept of the use of arrays of microfocus X-ray tubes based on field emission silicon nanocathodes is proposed. A new λ-tunable microfocus source of X-ray radiation, based on a thinfilm transmission target with field emission nanocathode with tunable wavelength, is proposed. The possibility of decreasing the exposed area size to 20 nm and smaller by varying the tube blocking voltage is shown. The use of these X-ray sources opens a new way of developing maskless X-ray lithography.

The results of the studies of laser processing of alkoxide aluminum hydroxides with micrometer and nanometer particle sizes are presented. It is shown that the pseudo-boehmite processing process and phase composition of formed oxides are controlled by particle packing, laser radiation propagation in powder, and specific energy deposition. The main phases formed upon laser heating are γ, α-Al₂O₃; the content of δ, θ-Al₂O₃ is low. The minimum corundum crystallite size is ∼50 nm.

New data on variations in vertical distribution of stratospheric ozone overMoscow in the cold half-year of 2015–2016 are presented. This period differed significantly from previous winters in a number of stratospheric parameters. The features of these ozone variations are considered and their relation to the stratospheric dynamics is studied. The most significant decrease in the ozone concentration in comparison with average values was observed at the beginning of March, 2016. The development of further significant ozone layer depletion similar to that occurred in spring 2011 was prevented by major sudden stratospheric warming in March 2016.

Nature of the defects in solid samples generated under the surface irradiation by a pulse of a CO₂-laser is investigated by the method of acousti©emission analysis. The laser pulse energy of 1.5 J was insufficient for destroying the sample. The samples were rods made from crystal (aluminum, copper) or amorphous (glass) materials. Acoustic emission signals from a rod face were studied which arise under the action of the laser radiation focused onto the opposite face of the rod. Analysis of data obtained shows that local structural changes arise in all the samples investigated. Defects in the form of microscopic cracks have been generated, and in the case of glass (the most fragile material), the cracks existing prior to irradiation have been developed.