The quantum-mechanical problem of the motion of a charged particle in a magnetic field is considered. The properties of the Wiener measure under transformations of the functional integration variable of a specific type are investigated. It is shown that the functional integrals for a particle in a uniform magnetic field are equivalent to those for a free particle.
This paper presents the results of sequential irradiation of the YBa _2 Cu _3 O _7-δ superconducting layer of a 2G HTS tape using atomic and cluster argon ions. It is shown that two-stage irradiation with monomers at a grazing incidence angle of 85 ^∘ made it possible to remove a-orientated crystallite protrusions, significantly reducing the root-mean-square (RMS) roughness. Subsequent surface processing with cluster ions at normal ion incidence results in smoothing of the surface topography in the range of spatial frequencies from 0.5 to 10 μ m ^-1 . It is worth noting that, within the framework of this method, the depth of the modified layer does not exceed 10–20 nm, which indicates that no structural damage is introduced into the bulk of the superconducting film.
Single crystals of the overdoped iron pnictide Ba _0.45 K _0.55 Fe _2 As _2 with T_c≈ 29 K have been studied. The current–voltage characteristics of planar mechanically controlled break junctions at various temperatures have been obtained and analysed. The temperature dependence of the self-field bulk critical supercurrent in zero magnetic field is successfully described within a two-band model, which made it possible to estimate the values of the large and small superconducting gaps, their characteristic ratios, and the partial contributions of the two effective bands to the conductivity.
This review focuses on methods for the production of promising medical radionuclides using photoproton nuclear reactions. Primary attention is paid to theranostic isotopes, such as lutetium isotopes ^177 Lu and rhenium isotopes ^186,188,189 Re, which can be obtained with high radionuclide purity. Of particular note is an innovative scheme for producing the diagnostic positron-emitting radioisotope zirconium ^89 Zr via photoproton reactions on molybdenum, which ensures high radionuclidic purity of the preparation and enables production organized according to the principle of a generator system. The leading role of the Skobeltsyn Institute of Nuclear Physics at Lomonosov Moscow State University in the development of this field in Russia is highlighted, which involves fundamental research on the photonuclear fission, obtaining reliable cross sections for photonuclear reactions and their subsequent application in medical technologies and clinical practice.
Using wave phenomena initiated in Kuril Lake (Kamchatka Peninsula, Russia) by the 8.8 Mw Kamchatka earthquake as an example, the formation of seismogenic seiches in enclosed bodies of water on land is analyzed. Within the framework of linear potential wave theory, it is shown that the primary contribution to the amplitude of seiche oscillations comes from the first few eigenmodes, which can be considered long-wavelength. The contribution of higher eigenmodes decreases inversely proportional to the square of the frequency. Seiches generated by the 8.8 Mw Kamchatka earthquake in Kuril Lake were numerically simulated using linear shallow-water equations. It was shown that in narrow bays and straits, lake level fluctuations could reach 5 m, and current velocities could reach 2 m/s. The numerical results for the ‘‘Kordon Ozerny’’ point (2.3 m, 1.1 m/s) are consistent with eyewitness accounts.
