Mode Coupling at around M-Point in PZT

The question of the microscopic origin of the M-superstructure and additional satellite peaks in the Zr-rich lead zirconate-titanate is discussed for nearly 50 years. Clear contradiction between the selection rules of the critical scattering and the superstructure was found preventing unambiguous attributing of the observed superstructure either to the rotation of the oxygen octahedra or to the antiparallel displacements of the lead cations. Detailed analysis of the satellite pattern explained it as the result of the incommensurate phase transition rather than antiphase domains. Critical dynamics is the key point for the formulated problems. Recently, the oxygen tilt soft mode in the PbZr0.976Ti0.024O3 (PZT2.4) was found. But this does not resolve the extinction rules contradiction. The results of the inelastic X-ray scattering study of the phonon spectra of PZT2.4 around M-point are reported. Strong coupling between the lead and oxygen modes resulting in mode anticrossing and creation of the wide flat part in the lowest phonon dispersion curves is identified. This flat part corresponds to the mixture of the displacements of the lead and oxygen ions and can be an explanation of the extinction rules contradiction. Moreover, a flat dispersion surface is a typical prerequisite for the incommensurate phase transition.

FEATURES OF DISTRIBUTION OF CASES OF HEAVY RAINS IN THE FLAT AND MOUNTAINOUS PARTS OF THE REPUBLIC OF BASHKORTOSTAN

The article presents the results of a study of cases of heavy rains in the Republic of Bashkortostan. For a complete analysis, the authors also included cases of precipitation with a total of 15 mm or more for a period of no more than 12 hours. For the flat part of the Republic of Bashkortostan, urgent observation data were used at the Ufa-Dema weather station, for the mountainous part - at the Tukan weather station. Cases of heavy rains were detected from May to November in the period 1966-2018. The main regularities of the distribution of cases of heavy rains according to the criteria of the amount, timing, months of manifestation are shown. The statistical characteristics of cases for the periods 1966-1994 and 1990-2018 are compared. It was revealed that in the mountainous part of the republic, compared with the plain, there are a third more cases of heavy rains. Also, the orographic features of the Southern Urals caused the formation of 38 cases of dangerous hydrometeorological phenomena, while no cases were registered at the weather station of the Bashkir Urals under consideration.

COMBINED EXTRUSION OF GLASSES WITH A CONICAL BOTTOM. KINEMATIC AND STRESS STATES OF THE PLASTIC REGION LOCATED UNDER THE CONICAL SURFACE OF THE PUNCH

For extrusion of glasses with a conical bottom using the method of plastic flow by A. L. Vorontsov, the kinematic and stress states of the extruded metal in the area of the plastic deformation center located under the conical surface of the punch were determined. The resulting formulas will be used to determine the stress state in the region of the hearth located under the central flat part of the punch-son՚s working end. In the future, the results of this mechanical and mathematical analysis will also make it possible to investigate the question of the presence of the taper of the punch, which is optimal in terms of strength.

FORECAST OF LOESS PSEUDOKARST FLAT PART OF THE CRIMEAN PENINSULA

The article briefly discusses the supposed development of the loess pseudokarst of the plain part of the Crimean Peninsula. The formation of pseudokarst forms, peculiarities of loess pseudokarst, and the geology of the Crimean Peninsula are described in detail.

Comparative analysis of two groups of patients according to the results of cataract phacoemulsification in combination with silicone oil removal through flat part of the ciliary body and posterior capsulorhexis in the long term after retinal detachment surgery

Purpose. To conduct a comparative analysis of two groups of patients according to the results of cataract phacoemulsification in combination with the silicone oil removal through flat part of the ciliary body and posterior capsulorhexis in the long term after retinal detachment surgery. Material and methods. 30 patients with a diagnosis of cataract, avitria, tamponade of the vitreous cavity with silicone oil OXANE 5700 were under observation. Patients were randomly divided into two groups. In both groups, the infusion system was installed through port 25 Ga located 3–4 mm from the limb, cataract phacoemulsification was performed in the first stage. In the first group (15 patients), silicon oil was removed through the posterior capsulorexis using a curved aspiration cannula of caliber 18 Ga. In the second group (15 patients) silicon oil was removed using aspiration through the second port of 25 Ga. The assessment of the functional and anatomical state after surgery was based on data from visometry, autorefractometry, ultrasound B-scanning of the vitreous cavity, and optical coherence tomography of the macular area. Assessment of patient satisfaction with the subjective level of quality of life was carried out using the validated visual function questionnaire Visual Function (VF-14). Results. In both groups, on average, there was a significant increase in the best corrected visual acuity. According to B-scan data, emulsified silicone oil particles were less detected in patients after removal of silicone oil through posterior capsulorexis. The subjective level of quality of life of each patient improved significantly in both groups. Conclusion. Performing the combined operation of cataract phacoemulsification with the removal of silicone oil through the posterior capsulorhexis in comparison with the silicone oil removal through the flat part of the ciliary body can equally improve visual function. Satisfaction with treatment results was slightly higher in the group with silicone oil removal through posterior capsulorexis. Key words: cataract, avitria, silicone oil, posterior capsulorexis.

PROBLEMS OF LAND USE IN WATER PROTECTION ZONES OF SMALL RIVERS

The article deals with problems related to non-compliance with environmental legislation in water protection zones of small rivers. The state of water protection zones of small rivers in the territory of RSO-Alania, both in the mountainous part of the Republic and in the flat part, is mainly assessed. Recommendations are given for improving activities in the field of environmental compliance in the protected areas of small rivers.

Features of heating technology at induction thermal processing with external electromagnetic field

According to the data of performed calculations and modeling of the hardening process, a design of inductors with magnetic cores for hardening long flat parts has been developed. At the design stage of this type of inductors, it was necessary to find out the degree of influence of the magnetic circuit design on the distribution of the temperature field during heating. To do this, we simulated electromagnetic and temperature fields to assess the concentration of the electromagnetic field at different heights of the “legs” of the inductor. As a result, a significant effect of the length of the “legs” of the magnetic circuit on the intensity of heating and the operability of the system as a whole was established. It is noted that insufficient height of the “leg” leads to a significant decrease in the field concentration, which leads to insufficient heating temperature and uneven distribution of heat zones in the heated part. In turn, an increase in the height of the “legs” leads to a narrowing of the heat release zone in the part compared to the total width of the coil and magnetic circuit. With a significant lengthening of the “legs”, the cooling circuit of the inductor will not be able to remove heat from the magnetic circuit obtained from the part, which will lead to the destruction of the magnetic circuit. The developed design of a two-turn single-circuit inductor and the general methodology made it possible to obtain a high-quality hardened layer with a depth of up to 3 mm with the formation of a martensitic structure of the required hardness on a planar-type flat part without significant energy loss. The part was machined by fixing it on a rigid base to compensate for the effect of temperature changes in linear dimensions. To obtain a uniform gap between the part and the inductor, a special pressure roller was used. The resulting structure of the hardened layer adequately meets the stated requirements for the part. The results of the research were used to develop a flat part of the “guide” type for lifting equipment (for example, a guide for the movement of the traction chain) and were introduced into production.

Near-$$AdS_2$$ perturbations and the connection with near-extreme Reissner–Nordstrom

The geometry very near the horizon of a near-extreme Reissner–Nordstrom black hole is described by the direct product of a near-$$AdS_2$$AdS2 spacetime with a two-sphere. While near-$$AdS_2$$AdS2 is locally diffeomorphic to $$AdS_2$$AdS2 the two connect differently with the asymptotically flat part of the geometry of (near-)extreme Reissner–Nordstrom. In previous work, we solved analytically the coupled gravitational and electromagnetic perturbation equations of $$AdS_2\times S^2$$AdS2×S2 and the associated connection problem with extreme Reissner–Nordstrom. In this paper, we give the solution for perturbations of near-$$AdS_2\times S^2$$AdS2×S2 and make the connection with near-extreme Reissner–Nordstrom. Our results here may also be thought of as computing the classical scattering matrix for gravitational and electromagnetic waves which probe the region very near the horizon of a highly charged spherically symmetric black hole.