A great research breakthrough that occurred in materials science twenty years ago has brought new metallurgical alloy design principles and made it possible to create a unique kind of artificial materials - multi- element concentrated alloys. These complex solid solutions reveal unique crystalline structures and promising physical and chemical properties. All of these alloys are interesting for their functionality, but they have not yet been introduced into daily life due to their high price and complexity of production. It has recently been proposed that electrical resistance strain gauges and pressure sensors are among the most suitable practical applications in which these materials can be efficiently implemented. The further development of such alloys requires an improved understanding of the physical mechanisms behind high strain gauge sensitivity in these systems. This study focuses on a comprehensive analysis of the effects of pressure and uniaxial stress on electrical resistivity in the equiatomic TiZrHfTa high-entropy alloy, which is a typical representative of this family of materials. We measure electrical, magnetic, and thermal properties of the system and calculate its electronic structure and elastic constants to address issues associated with the strain and pressure effects, as well as evaluate the overall functionality for this kind of alloys in terms of possible passive electronic sensors. The tested alloy exhibits virtually temperature-independent resistivity and a superior strain gauge factor as large as 5.17. By analyzing the obtained data, we suggest that elastic anisotropy effects playa key role in the strain-sensitive behavior of refractory high-entropy alloys.

The design and principle of operation of ILU-series industrial electron accelerators produced by the Budker Institute of Nuclear Physics are considered using the examples of the ILU-10 accelerator with an accelerated-electron energy of 5 MeV and a mean beam power as high as 50 kW and the ILU-14 accelerator with an electron energy of up to 10 MeV and a beam power as high as 100 kW. The mechanisms of interaction between the electron beam and microbiological samples, the peculiarities of the depth profile of the absorbed dose in a substance, and the design of the electron-beam converter into bremsstrahlung are described. By using this converter, it is possible to increase the mass thickness of treated products several times compared to the electron mode. The throughput of ILU accelerators during radiation sterilization and electron pasteurization of products is estimated.

The magnetic properties of Mn1–xRhxSi solid solutions with a noncentrosymmetric structure B20 synthesized at a pressure of 8 GPa and temperatures of 1500–1770 K have been studied in detail in a wide temperature range of 2–300 K in magnetic fields up to 9 T. An anomalous increase in the Curie temperature TC of compounds with 0.15 ≤ x ≤ 0.8 by a factor of 8.4–11.5 compared to the pure helical magnet MnSi has been found. It has been established that the Curie temperature TC increases with the rhodium content to TC(x = 0.15) = (244 ± 4) K, TC(x = 0.4) = (299 ± 5) K, and TC(x = 0.8) = (334 ± 6) K. Uniquely high magnetic transition temperatures up to room values occur in the disordered ferromagnetic Griffiths phase and may be due to the spin-fluctuation mechanism of enhancement of the magnetic interaction.

В данной работе представлены расчеты систем выпуска и поворота электронного пучка, разработанных для импульсных ускорителей электронов серии ИЛУ за последние годы. В частности, описана система сканирования пучка, отличительной особенностью которой от предыдущих аналогов является введение коррекции формы сканирующего магнитного поля. Приведены результаты испытаний данной системы на ускорителе ИЛУ-10 (5 МэВ, 50 кВт). Рассмотрена система выпуска пучка для ускорителя ИЛУ-14 (10 МэВ, 100 кВт), содержащая систему фокусировки пучка и коррекции его оси после выхода из ускоряющей структуры, а также выпускное устройство, позволяющее увеличить ширину сканирования пучка до 160 см. Также в работе описана система для поворота немонохроматичных электронных пучков, состоящая из двух магнитных зеркал, позволяющая компенсировать угловые расходимости пучка и получать после поворота электронный пучок с фазовыми характеристиками близкими к начальным. Приведены экспериментальные данные поворота электронного пучка на 180º.

The main purpose of mechanisms with walking beams is the periodic movement of goods, which is carried out by alternately lifting vertically and moving horizontally, and at the same time contact with the load is excluded. The movement cycle includes four phases: lifting the load using movable beams, moving the load one step, lowering the load onto fixed beams, idling – moving the movable beams to their original position. In fact, it is a machine, since it includes two mechanisms (a vertical lifting mechanism and a horizontal movement mechanism) and a control device. Mechanisms with walking beams occupy the largest area in steelmaking and rolling shops of metallurgical enterprises. In the ferrous metallurgy, these mechanisms are mainly represented by three implementations: refrigerators of continuous casting machines, refrigerators of rolling mills, mechanisms for moving workpieces in the heating furnaces of rolling mills. The article is devoted to the topic of metallurgical machines with walking beams, their loading methods, location, work cycles, working conditions, and frequent malfunctions. The main methods of adapting a structure with walking beams to various operating conditions are considered, as well as the main causes of failures, are considered. The review of existing structures and design features of mechanisms with walking beams used in metallurgical enterprises is carried out. The characteristic failures and adaptation of the design of mechanisms with walking beams for operating conditions are determined.

Modern gyrotrons provide radiation in a wide range of frequencies and powers, which is used in a variety of areas of fundamental and applied research connected with the problem of plasma formation and heating.The A.V. Gaponov-Grekhov Institute of Applied Physics of the Russian Academy of Sciences is conducting a wide range of studies of gas discharge in a magnetic field under electron cyclotron resonance conditions. For these studies, gyrotron radiation with frequencies from 24 to 75 GHz and a peak power of up to 200 kW is used. The use of such high-frequency and powerful microwave systems has made it possible to obtain original results in the development of sources of intense ion beams of different types, to build compact and powerful neutron generators, to study fundamental kinetic processes in highly nonequilibrium plasma with hot electrons, and to simulate a number of astrophysical phenomena in the magnetospheres of the Earth and other planets.Studies of atmospheric pressure discharge in focused beams of gyrotron radiation with a frequency of up to 1 THz have shown significant prospects for creating of effective sources of extreme ultraviolet radiation with 13.5 and 11.2 nm wavelength based on such plasma, as well as plasma-chemical complexes, for example, for the decomposition of carbon dioxide and other compounds that require innovative methods for effective processing.The brief overview of the recent plasma studies using high power gyrotron radiation in frequency range from 24 GHz to 1 THz are presented, the future prospects of proposed technologies are discussed.

A stable point-like thermodynamically-equilibrium plasma with diameter of 1 mm, density of $3 \times 10^{17}$ $\mathrm{cm}^{-3}$, and temperature of 4-4.5 $\mathrm{eV}(\mathbf{4 6 0 0 0 - 5 2 0 0 0 ~ K})$ was obtained in a continuous Kr- N 2 laser discharge at NovoFEL at an average radiation power of less than 200 W. Such plasma is a bright source of VUV radiation, and when its temperature reaches $10-12$ eV, it can be a bright source of EVUV radiation, necessary for modern photolithography.

Complex concentrated multi-element metallic systems, commonly referred to as high-entropy alloys (HEAs), exhibit a combination of unique physical properties when compared to conventional metallic materials. That makes this class of alloys promising for a variety of functional applications. However, HEAs are too expensive to be used for material-intensive products like structural materials, so their functionality can only be implemented in micro-scale applications. The electrical resistance sensors for detecting and measuring tension stress, pressure, micro-displacements, weight, and other physical parameters seem to be appropriate areas where HEAs could find their own place. This study addresses strain gauge characteristics in several HEAs, such as TiZrHfNb, TiZrHfNbTa, and FeCoCrMnNi (Cantor alloy). We discuss the pressure and strain gauge sensitivities in the systems employing experimentally measured electrical, magnetic, and thermal properties as well as ab initio calculations. We conclude that HEAs can be considered as promising materials for strain-sensitive resistance transducers that outperform commercial alloys in terms of a combination of performance characteristics.

The synthesis of diamonds in traditional growth systems based on Fe, Co and Ni does not allow overcoming the semiconductor level of boron doping of diamond, presumably because of a high affinity of boron to borideforming metals. For the first time, noble metals that do not form borides-silver and gold-are used as growth media for the synthesis of heavily boron-doped diamonds at 8-9 GPa. Gold and silver are not catalysts for the transformation of graphite to diamond, whereas elemental boron is catalytically active at eutectic melting temperatures above 2500 K. It is found that the synthesis of diamond in Ag-B and Au-B growth media starts at temperatures close to the melting temperatures of Ag and Au, 1600 and 1800 K, respectively. Calculations show that molten Au and Ag dissolve boron atoms without a significant change in the electronic structure of the solution, suggesting that the metal melts serve as a carrier for the boron catalyst. The resulting polycrystalline diamond contains dispersed inclusions of Ag and Au, as well as traces of boron carbide; the formation of borides is not detected. The transport measurements of the diamond samples reveal a transition to a superconducting state in the temperature range from 4.5 to 2.5 K. Raman spectroscopy confirms the heavy boron doping of diamond. Thus, we show that melts of "non-catalytic" metals that do not form borides can be effectively used to synthesize boron-doped conductive/superconducting diamonds at relatively low temperatures.

The results of magnetic measurements, electron spin resonance, heat capacity, resistivity, and magnetocaloric effect as well as density functional theory (DFT), are presented for the compound NdRh2 (MgCu2-type structure). This compound was synthesized at a pressure of 8 GPa and a temperature of 1700 K. The magnetic properties of the material are shown to be determined by the high-temperature (over 400 K) spin polarization of the 4d Rh electrons and by the ferrimagnetic (FiM) interaction of Rh and Nd magnetic subsystems. Concurrently, the spontaneous magnetization of the spin polarization of 4d Rh electrons is approximate to 0.01 mu B/Rh, while the Nd magnetic moment is approximate to 1.7 mu B/Nd. This leads to complicated magnetic behavior with long range FiM order at TC less than or similar to 7 K at zero field and with wide temperature range of spin fluctuations TC<T less than or similar to 50 K. Specific heat and resistivity data provide corroboration of the spin fluctuation regime with the spin fluctuation temperature Theta sf approximate to 28.5 K. The optimal critical parameters were identified as beta=1.18 +/- 0.02, gamma=0.85 +/- 0.02, and TC approximate to 40 K from modified Arrott plotting, which are distinct from any conventional universality class. The maximum magnetocaloric effect, when the magnetic field changes from 0 to 9 T, Delta H=9 T occurs at T approximate to 11 K and the magnetic entropy change reaches -Delta Sm=7.0 J (kg K)(-1). In our DFT calculations, the FiM arrangement was obtained, with values of magnetic moments of Nd and Rh. Additionally, the Fermi surface was constructed.

.На ускорителе ИЛУ-6 в ИЯФе постоянно проводится радиационная обработка различных образцов. Основные направления работы: стерилизация и деконтаминация медицинской продукции, обработка пищевой и сельскохозяйственной продукции, исследование радиационной стойкости материалов, облучение биологических объектов, модификация органических соединений, в том числе энергонасыщенных, радиационная инициация полимеризации, радиационно-термическое воздействие на органические и неорганические соединения. На этой установке были отработаны процессы стерилизации имплантатов позвоночных дисков и радиационной модификации матриксов для имплантатов кровеносных сосудов. Диапазон рабочей дозы в экспериментах варьировался от 7 Гр при облучении мышей до 500 МГр при исследовании радиационной стойкости композитных материалов. При проведении радиационно-термических экспериментов максимальная температура в реакционной зоне достигла 1400°С.

Despite the 60-year history of research on band magnetism in MnSi, the field remains a vibrant area of study. This area is still of great interest although the physics of weak itinerant magnetism is complicated because of small magnetic moments and an uncertain role of local interactions. This work presents Rh-doped MnSi compounds in which a high-spin (HS) state of Mn magnetic moments has been detected in 55Mn nuclear magnetic resonance (NMR) measurements. The doping of MnSi with Rh results in a transition to the HS state for Mn1-xRhxSi at x = xc approximate to 0.025 with two Mn magnetic moments approximate to 1.3 and 2.2 mu B, which are ordered just below 200 K. This transition occurs only in part of the Mn atoms, while the other Mn atoms remain in a low-spin (LS) state. Concurrently, the Dzyaloshinsky-Moriya (DM) interaction for LS helical states of Mn moments is preserved up to x approximate to 0.13. Furthermore, variations in the Rh concentration result in discernible alterations in the magnetic field-temperature phase diagrams. In this case, it was observed that the temperature range of existence of the A phase, host skyrmion lattice, was markedly increased in presence of Rh doping, up to x = 0.025 at least. Small-angle neutron scattering has evidenced the existence of a skyrmion lattice in the helicoidal magnetic phase of Mn0.98Rh0.02Si. The Rh-doped MnSi compound thus demonstrates the coexistence of the HS and LS states of Mn. Our DFT calculations has indicated that this behavior can only be the case when Rh occupies not only Mn but also Si positions in the MnSi compound. Furthermore, our findings indicate that Ir doping of MnSi does not result in the formation of a high-temperature phase, but rather in the suppression of the DM interaction. Although Rh and Ir belong to the same column of Mendeleev's periodic table, they exhibit disparate behaviors upon MnSi doping.

A recent report on obtaining the n-type conductivity in diamonds doped with boron-oxygen complexes in a metal solvent (X. Liu et al., PNAS 2019) stimulates interest in the synthesis of diamonds in heterohydrocarbon systems with oxygen and boron. The simultaneous effect of boron and oxygen heteroatoms on phase transitions in a hydrocarbon system is examined in phenylboronic acid C6H5B(OH)2 at pressures of 7-8.5 GPa and temperatures up to 1600 degrees C. At pressures of about 7 GPa and temperatures up to 1100 degrees C, the transformation of the precursor occurs through the stage of polymerization into a graphane-like phase with the subsequent formation of nanographite. Micro- and nanodiamonds are synthesized at 8.5 GPa and 1600 degrees C from the initial precursor and nanographite, which is a product of preliminary carbonization, respectively. Despite the presence of oxygen and boron in the growth system, the n-type conductivity in diamonds and nanographite is not detected. It is found that the degree of boron doping of diamond in hydrocarbon systems decreases in the presence of oxygen with a high chemical affinity to boron and that nanodiamonds in the carbonized product can be obtained when volatile components leave the system.

— The review presents the experiments performed with the KEDR detector at the e^ + e^ - collider VEPP-4M in the energy range of √(s) = 1.84–3.88 GeV. The cross section of e^ + e^ - annihilation to hadrons was measured at 22 points of this range and the search for narrow resonances was conducted below 3.1 GeV. The masses of J / . -0emψ and ψ (2S) mesons were measured with a record accuracy better than 3 ×10^ - 6 ; their partial and total widths were determined. Measurements of the tau lepton mass and masses of charged and neutral D mesons were performed with high precision. The measurements of the ψ (3770) parameters are discussed, and attention is drawn to some inconsistency of the procedure employed by the Particle Data Group for determining its parameters.

In this work gas discharge ignited by gyrotrone radiation with frequency 1THz were carried out. Breakdown curves were calculated both for selfignited and initiated discharges. There was shown that in case of breakdown by the pulse radiation with duration longest then several microseconds electric field threshold is the same as in case of continuous wave breakdown. Also the possibility of using a terahertz gyrotron as a radiation source for discharge in gas targets on installations for extreme ultraviolet photolithography was assessed.

Unique carbonization behavior of 1-fluoroadamantane was revealed at pressures 5.5-9 GPa and temperatures up to 1300 degrees C. In course of the carbonization, formation of nanodiamonds was detected at record low temperature of 420 degrees C and pressure of 5.5 GPa. Analysis of sample mass decrease implies that for the samples synthesized at temperatures up to 600-800 degrees C the decomposition reaction proceeds with release of molecular hydrogen, and for those synthesized at higher temperatures with formation of volatile hydrocarbons. At 8-9 GPa, sustained growth of nanodiamonds is observed over whole temperature range studied, while at 5.5 GPa, graphitic sp2 carbon is formed along with nanodiamonds at temperatures above 600 degrees C. It is suggested that the molecular hydrogen formation regime of carbonization is critically important for nanodiamond nucleation. Subsequent growth of nanodiamonds is determined by the pressure-dependent catalytic activity of the C-H-F growth medium. Trans-port properties measured on the 5 nm-nanodiamonds demonstrate p-type semiconductor behavior with activa-tion energy of 0.1 eV at room temperature and unusual non-monotonic pressure dependence of conductivity. Transmission electron microscopy reveals surface-bound sp2-C domains on nanograins; vibrational spectroscopy indicates strong surface hydrogenation of synthesized nanodiamonds. Modeling confirms plausibility for for-mation of metastable surface with reconstructed sp2 and hydrogenated fragments allowing for surface conduc-tivity. Facile synthesis of nanodiamonds from 1-fluoroadamantane can be of great interest for fundamental investigations and practical applications. Our experiments suggest that fluorine-containing fluids may play a significant role in genesis of natural diamond.

Sub-terahertz and terahertz frequency ranges remain the least studied from the point of view of gas discharge physics. Investigation of terahertz gas discharge, sustained by the powerful focused beams of the electromagnetic radiation, has become possible recently due to the development of the powerful sources in this range (FELs and gyrotrons) and is of interest both from a fundamental research and from possible applications. This work presents the results of the studies of the discharge propagation under the action of the focused beam of sub-terahertz (250 GHz) gyrotron. The discharge propagation velocity towards electromagnetic radiation was measured in air in the wide pressure range (0.01 - 1 atm). The focusing system provided the size of the focal spot of (2-3)& BULL;& lambda;, which ensured the investigation of discharge phenomena in a wide pressure range. The optical glow of the discharge was recorded with the help of a speed camera. The discharge appeared in the focal spot spread towards heating radiation into the area with the field intensity much less than one in the focal spot. Velocity of the discharge propagation was measured by using photos from speed camera with small exposure (down to 20 ns). It was demonstrated that discharge velocity increase along with pressure decrease and drops with electric field decrease as it moves away from the focal spot.

We report on a comprehensive experimental and theoretical study of Fe 1 − x Rh x Ge compounds, within the entire concentration range x ∈ [0 . 0 − 1 . 0], using X-Ray diffraction, small-angle neutron scattering, magnetometry and theoretical calculations. While FeGe and RhGe are single phase helimagnet and unconventional superconductor, respectively, an internal splitting of the crystallographic and magnetic states is found for intermediate compositions x ∈ [0 . 2 − 0 . 9]. A theoretical analysis of the stability of the two detected phases, together with the experimental data, indicate that this splitting preserves a common space group and occurs within single crystallites. Despite their apparent similarity, these two phases however display different magnetic structures, with distinct ferro- and helimagnetic character.

We consider the prospect of development a point-like source of vacuum ultraviolet radiation based on a plasma discharge sustained by terahertz radiation from Novosibirsk free electron laser.

Crystal and magnetic structure, physical properties (heat capacity, electrical resistivity, magnetic ac -suscepti-bility) of the ordered double manganite PrBaMn2O6 under high external pressure are presented for the first time. Powder neutron diffraction and measurements of physical properties are performed at external pressure up to 5.2 GPa in the temperature interval 50-320 K. Unit cell parameters are determined, the magnetic moment of manganese atoms is calculated with full-profile analysis, linear and volume compression coefficients are esti-mated. According to the neutron diffraction analysis, the material becomes A-type antiferromagnetic insulator at external pressure, while the measurements of physical properties reveal weak signal of the conducting ferro-magnetic state. This discrepancy is explained by a presence of ferromagnetic conducting clusters in the anti -ferromagnetic insulator matrix. The NMR data confirm such an explanation as two contributions from ferromagnetic and antiferromagnetic fractions at ambient pressure have been detected.