Том 108, № 1 (2018)

Data from the NUCLEON space observatory give a strong indication of the existence of a new universal cosmic ray “knee”, which is observed in all groups of nuclei, including heavy nuclei, near a magnetic rigidity of about 10 TV. Universality means the same position of the knee in the magnetic rigidity scale for all groups of nuclei. The knee is observed by both methods of measurement of particles energy implemented in the NUCLEON observatory—the calorimetric method and the kinematic method Kinematic Lightweight Energy Meter. This new cosmic ray knee is probably connected with the limit of acceleration of cosmic rays by some generic or nearby source of cosmic rays.

The isotope ¹⁴⁹Tb is the only known isotope decaying both by emission of alpha particles and positrons. This unique feature makes it possible to unite in one radionuclide two main tools of nuclear medicine: cancer therapy by α particles and diagnostics using positron emission tomography. The existing ways of production of ¹⁴⁹Tb are far from being practical. In this paper, a simulation of the excitation functions of the ¹⁵¹Eu(α, 6n)¹⁴⁹Tb and ¹⁵³E(α, 8n)¹⁴⁹Tb nuclear reactions was carried out. The cross sections in the maxima (approximately 65 and 80 MeV, respectively) are predicted to reach one barn, and the targets could be made from natural europium. Thus, these reactions can serve as a basis of a new promising technology for production of ¹⁴⁹Tb isotope for use in a modern field of nuclear medicine, theranostics.

Typical experimental measurement is set up as a study of the system’s response to a stationary external excitation. This approach considers any random fluctuation of the signal as spurious contribution, which is to be eliminated via time-averaging, or, equivalently, bandwidth reduction. Beyond that lies a conceptually different paradigm—the measurement of the system’s spontaneous fluctuations. The goal of this overview article is to demonstrate how current noise measurements bring insight into hidden features of electronic transport in various mesoscopic conductors, ranging from 2D topological insulators to individual carbon nanotubes.

The effect of magnetic field on the nanohardness of monocrystalline silicon doped with phosphorous by ion implantation is studied. It is found that a magnetic field of certain parameters can increase the nanohardness of monocrystalline silicon doped with phosphorous by ion implantation, and this increase can be eliminated by annealing monocrystalline silicon doped with phosphorous by ion implantation at 800°C for 780 s. For the monocrystalline silicon doped with phosphorous by ion implantations that have not been exposed to a magnetic field, annealing them at 800°C for 780 s cannot affect their nanohardness, but exposing them to the magnetic field mentioned previously can no longer affect their nanohardness after annealing. The mechanism of all these phenomena is discussed. A possible mechanism that a magnetic field can promote the disbanding of vacancy clusters, and a possible mechanism of magnetically stimulated clusters’ disbanding and magnetoplastic effect are put forward.

The electromigration of small vacancy islands on the Cu(100) surface has been studied using the self-learning kinetic Monte Carlo method. The dependence of the drift velocity of vacancy clusters on their size, temperature of the substrate, and magnitude and direction of the electric current density has been obtained. It has been shown that the dependence of the drift velocity of small clusters on their size has a pronounced oscillatory character. These oscillations are due to the difference in the mechanisms of diffusion of “fast” and “slow” clusters. It has been found that events associated with the diffusion of dimers should be taken into account for the correct simulation of the electromigration of vacancy clusters.

The morphological stability of the interface between two fluids has been analyzed for the case where one of them displaces the other in a radial Hele-Shaw cell. The numerical calculation has shown for the first time that the critical size of instability decreases with an increase in the perturbation amplitudes of the interface and reaches a value previously determined from independent analytical calculations of the thermodynamic entropy production and the maximum entropy production principle. This reason is important evidence for the hypothesis that the entropy production makes it possible to predict nonequilibrium phase transitions in hydrodynamic systems (i.e., it is an analog of the thermodynamic potential). In other words, the entropy production determines a kinetic binodal, i.e., the interface of a metastable region in the case of perturbations with arbitrary amplitude.

It is shown that the magnetotransmission of unpolarized infrared radiation in the magnetostrictive crystal of CoFe₂O₄ ferrite spinel in the Faraday geometry can be as high as 30% at a magnetic field of 7.5 kOe. This effect is related to the field-induced shift of the fundamental absorption edge, as well as to changes in the intensity and positions of the impurity absorption bands. Correlation between the magnetic field dependence of magnetotransmission and magnetostriction is revealed. The contribution of the Faraday effect to the magnetotransmission is estimated. The analysis of magneto-optical and magnetoelastic characteristics taking into account the contribution of the deformation potential for the valence band is performed.

The theory and method for analysis of Mössbauer spectra of magnetic nanoparticles in a fluid have been developed by generalizing the model of the magnetic dynamics of a Néel ensemble of antiferromagnetic particles to the case of ferrimagnetic iron oxides. The resulting model describing the “superposition” of the magnetic dynamics and translational motion of nanoparticles in ferrofluids has been tested in application to the simultaneous analysis of Mössbauer spectra of “dry” magnetite nanoparticles and the same particles in glycerol.