Vol 45, No 11 (2018)

The solution of the problem of processing of a large data set when analyzing Raman spectra of a gas mixture is considered. The algorithm is based on the artificial neural network. Conditions for the use of neural networks in solving practical problems of real-time analyzing spectra, including that for remote search for heavy hydrocarbons are determined. The algorithm speed is estimated using computer aids with sequential and parallel data processing.

The schematic diagram of the compact transportable optical frequency standard based on the quadrupole transition in a single ¹⁷¹Yb⁺ ion with a relative instability at the levelx of 5 · 10⁻¹⁶, less than 1m³ in volume and less than 300 kg in weight is presented. The ionic trap and laser systems are described. Trapping and laser cooling of the ¹⁷⁴Yb⁺ ion are experimentally demonstrated.

Three-dimensional numerical PIC simulation allowed the detection and study of the formation of an electron bunch moving with relativistic velocity along a thin metal wire during its irradiation with a short laser pulse of relativistic intensity. The bunch motion is accompanied by electromagnetic surface-type pulses.

Silicon nanoparticles are obtained by nanosecond laser ablation of a single-crystal wafer under a deionized water layer. Nanoparticle generation mechanisms are studied depending on the incident energy density of laser radiation (7–12 J/cm²) and scanning speed (10–750 mm/s). At a scanning speed of 150–200 mm/s, a maximum of the extinction coefficient of obtained colloidal solutions of nanoparticles is observed, which can be caused by an increase in their mass yield.

Applying the theory of sources I consider the consequences of using field theoretical 3- graviton vertex instead of the vertex of general relativity. As an example I look for the lowest nonlinear terms in the exteriormetric of a spherically symmetric body. Themethod suggests that the algorithm of obtaining the metric cannot be reduced to solving the Einstein equation. It also seems that in nonlinear approximation the concept of a test particle moving in external gravitational field can be sustained only for a nonrelativistic particle.