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The positron annihilation lifetimes were measured using a 48V positron source in noncentrosymmetric cubic single crystals of CoSi, FeSi and MnSi. The following lifetimes were determined from the positron annihilation time spectra: 168(1) ps for CoSi, 114(1) ps for FeSi and 111(1) ps for MnSi. For single-crystal CoSi, the positron annihilation lifetime was also determined with a 22Na positron source. For CoSi, the lifetimes obtained from different positron sources are consistent. The differences in the positron annihilation lifetimes in MnSi and FeSi, on the one hand, and in the Weyl semimetal CoSi, on the other hand, are possibly caused by the formation of a positron + electron bound state (positronium).

Hyperfine interactions in the Bi1−xLaxFeO3 ferrites (where x = 0.0225, 0.075, 0.9) have been studied by means of 57Fe Mössbauer spectroscopy and 140Ce time differential perturbed angular γ–γ correlation methods. The information about the line shift δ, the lattice εlat and the magnetic εmag contributions to the quadrupole shift ε, isotropic His and anisotropic Han contributions to the hyperfine magnetic field Hhf on 57Fe nuclei, anharmonicity parameter m, distribution of the hyperfine magnetic field p(Hhf), and supertransferred hyperfine magnetic fields on 140Ce probe nuclei were obtained. In all studied compounds, the Fe ions are in a high-spin trivalent state. In the compounds with x = 0.0225 and 0.075 spatially modulated cycloidal magnetic structures exist. It was found that the sign of the effective constant of magnetic anisotropy Keff changes with the variation of x from 0.0225 to 0.075. The substitution of Bi by La increases the value of the hyperfine magnetic field on 57Fe nuclei from 494 kOe in Bi0.9775La0.0225FeO3 to 520 kOe in Bi0.1La0.9FeO3, i.e. by 26 kOe, while the corresponding supertransferred hyperfine magnetic field on 140Ce probe nuclei decreases.

The modernization of the detector system and control system of the neutron powder diffractometer (NPD) in the GEK-5 channel of the VVR-c reactor (Obninsk Branch, Karpov Institute of Physical Chemistry) is described. The PC-connected hardware and software complex, which ensures data acquisition and storage and control of the experiments, is created. The main modules of the NPD automation system and Sonix+ control software package, designed at the Frank Laboratory of Neutron Physics at JINR, are briefly described. The modernization has made it possible to increase the luminosity of the diffractometer and completely automatize the measurement process.

Recently, metal oxide nanoparticles (NPs) have attracted attention as promising components for the protection and stimulation of plant microclones in tissue culture in vitro. However, the effect of NPs on the genetic mechanisms underlying plant adaptive responses remains poorly understood. We studied the effect of column-shaped CuO NPs 50 nm in diameter and 70–100 nm in length at a concentration of 0.1–10 mg/L on the development of phytopathogenic fungi Alternaria alternata, Fusarium oxysporum, and Fusarium avenaceum in culture, as well as on the infection of downy birch micro-clones with phytopathogens and the level of genes expression associated with the formation of plant responses to stress induced by microorganisms. CuO NPs effectively suppressed the development of colonies of phytopathogenic fungi A. alternata and F. avenaceum (up to 68.42% inhibition at 10 mg/L CuO NPs) but not the development of a colony of F. oxysporum. Exposure to the NPs caused multidirectional responses at the level of plant genes transcription: 5 mg/L CuO NPs significantly increased the expression level of the LEA8 and MYB46 genes and decreased the expression of DREB2 and PAL. Infection with A. alternata significantly increased the level of MYB46, LEA8, PAL, PR-1, and PR-10 transcripts in birch micro-clones; however, upon exposure to a medium with NPs and simultaneous exposure to a phytopathogen, the expression of the MYB46, PR-1, and PR-10 genes decreased by 5.4 times, which is associated with a decrease in the pathogenic load caused by the effect of NPs and the simultaneous stimulation of clones in vitro. The results obtained can be used in the development of preparations based on copper oxide NPs for disinfection and stimulation of plant phytoimmunity during clonal micropropagation of tree crops.

We study 2D problems of surface growth theory of deformable solids and their applications to the analysis of the stress-strain state of AM fabricated products and structures. Statements of the problems are given, and a solution method based on the approaches of the theory of functions of a complex variable is suggested. Computations are carried out for model problems. Qualitative and quantitative results are discussed.

The paper considers the problem of torsion of a growing viscoelastic prismatic rod with integral boundary conditions at the ends. The process of continuous growth under the influence of torque is studied. The distributions of the intensity of tangential stresses at various stages of the building process are investigated. The calculations of the torsion problem of a prismatic rod with a section in the form of a regular triangle are presented.

The results of the production of the medical isotope 177Lu in the IR-8 research reactor are presented. The quantitative and qualitative characteristics of the desired radionuclide are determined. The radiochemical method of separating 177Lu from an irradiated target 176Yb by a combination of two electrochemical processes - cementation of ytterbium from acetate-chloride solution on sodium amalgam and electrolysis of an ytterbium solution in a single electrolytic cell - is proposed. The purification factor for removal of 176Yb from 177Lu was 105-106.

The dynamics of positronium bubble growth and dissipative energy loss accompanying this process were considered in the hydrodynamic approximation for liquid media with strongly differing values of the surface tension and viscosity. The driving force of the growth of the positronium bubble is repulsive exchange interaction between the electron inherent in the positronium atom and electrons of surrounding molecules. Intermolecular attraction (Laplace pressure) and viscous media retard bubble growth. In liquid helium and glycerol, the Ps formation time is comparable to or even longer than the parapositronium lifetime. Dissipative energy losses accompanying the bubble growth are substantially higher than the surface energy of the equilibrium bubble.

Hydrogen in palladium, Pd-H(D), is an interesting system because of the highly mobile hydrogen and the presence of a phase boundary below 100 K. Experimentally, however, the nature of this transition has not been established. Historically this transition around 55 to 100 K has been thought to be an order-disorder transition. Such a transition would produce a phase boundary with anomalies at specific hydrogen concentrations corresponding to the specific ordered structures. In order to check this phase boundary we have performed a detailed study of the hydrogen concentration dependence of the specific heat of PdHx over the temperature range from below 0.5 K to above 100 K using PdHx specimens with x up to 0.8753. The measured heat capacity has been analyzed as the sum of contributions due to the lattice specific heat of Pd, the electronic specific heat of PdHx, and the excess contribution caused by hydrogenation of the specimen. The excess specific heat result shows a sharp peak which indicates a phase boundary with transition temperature T1=55 K to 85 K depending linearly on the hydrogen concentration from x=0.6572 to 0.8753. We do not observe anomalies at specific x values as would be expected for the specific ordered structures.

Optical nonlinearities are crucial for advanced photonic technologies since they allow photons to be managed by photons. Exciton-polaritons resulting from strong light-matter coupling are hybrid in nature: they combine small mass and high coherence of photons with strong nonlinearity enabled by excitons, making them ideal for ultrafast all-optical manipulations. Among the most prospective polaritonic materials are halide perovskites since they require neither cryogenic temperatures nor expensive fabrication techniques. Here we study strikingly nonlinear self-action of ultrashort polaritonic pulses propagating in planar MAPbBr\\(_3\\) perovskite slab waveguides. Tuning input pulse energy and central frequency, we experimentally observe various scenarios of its nonlinear evolution in the spectral domain, which include peak shifts, narrowing, or splitting driven by self-phase modulation, group velocity dispersion, and self-steepening. The theoretical model provides complementary temporal traces of pulse propagation and reveals the transition from the birth of a doublet of optical solitons to the formation of a shock wave, both supported by the system. Our results represent an important step in ultrafast nonlinear on-chip polaritonics in perovskite-based systems.