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Seabuckthorn gene pool in collections of Lisavenko Research Institute of Horticulture for Siberia which is a division of the Federal Altai Scientific Center of Agro-BioTechnologies is represented by more than 14 thousand hybrid seedlings and over 450 varieties under selection. It allows to provide comprehensive selection on different agronomic traits and to achieve permanent assortment improvement. The main aim of the research was to select seabuckthorn varieties distinguished by characteristics that meet the requests of industrial sector with focus on various technological approaches. Seabuckthorn varieties of hybrid origin from crossbreeding of 1993-2005 were studied. The experiments were carried out in forest-steppe zone of Altai Krai in 2016-2020. According to the results of comprehensive evaluation, groups of the most promising varieties were proposed as a source of various agronomic traits. The potential of breeding activity was shown as well as possibility of seabuckthorn assortment improving was proved. In particular, within sweet-fruited varieties such samples as 57-01-1, 146-02-1 and 226-00-1 with sugar-acid index of 6.4, 5.4 and 5.3, respectively, have been selected as well as fruit of 198-99-3a and 62-01-2 varieties weighed about 1.0 g, that is almost 0.3 g higher compared to Chuiskaya variety (control) and Altaiskaya (the sweetest one). Two varieties - 149-00-3 and 664-00-2 - were included to the group with very low tear-off force of fruits - 95 and 110 g, respectively, which was significantly lower compared to the control (Chuiskaya) and the standard variety (Anastasia). That means high suitability of these varieties for harvesting by hand picking. The hybrid 185-99-5 had an average fruit weight of 1.67 g which was two times higher than fruit weight of the control variety. Highly promising red colored variety (258-03-1) had high oil content in fruits. That positions it as an extremely promising variety for seabuckthorn oil concentrate processing. Most of estimated varieties were included in various reference groups demonstrating by that the combination of agronomic traits.

The study of water-holding capacity in sea buckthorn green cuttings, as well as their ability to restore water content, has been carried out to improve nursery technological methods. In order to establish possible variety specifics, the varieties that significantly differ not only in their ability to rhizogenesis, but also in a range of biological features, have been used in the experiment. It has been found that the Essel variety has the maximum level of water-holding capacity (the water loss after 24 h of drying is 20.6%), while the minimum level was observed for the Augustina variety with an average water loss of 26.4%. A high dependence of water content restoring on water-holding capacity of green cuttings was revealed. In this regard, the Essel variety was characterized by maximum turgor-restore ability, reaching an average of 98.3% over the years of research after 48 h of saturation, while the Augustina variety had minimal values: 74.3%. The variety specifics and year particularities have the maximum level of influence on green cuttings’ water mode characteristics within the range of investigated factors (rhizogenesis stimulator, varieties, and year conditions). For water-holding capacity, the level of variety factor influence was 40.9%, while the year factor influence was 31.0%; for water restore ability after 48 h of saturation, the influence of these factors was 40.5 and 28.8% respectively. Direct influence of water mode peculiarities on rhizogenesis processes have not been revealed; however, the studied features should be taken into account in the range of criteria that provide successful rooting of several sea buckthorn varieties, in particular, the Augustina variety. No correlations between investigated water mode features and biological characteristics of the investigated varieties have been found.

This paper describes two approaches which have been developed in the past few years for the creation of electronically controlled steering of the microwave beam formed by multichannel auto-oscillators. The first one is based on two- and four-channel gyromagnetic nonlinear transmission lines operating in the generation mode at subgigawatts power level and decimeter wavelengths. The second approach uses Cherenkov superradiance in two and four parallel backward-wave oscillators with centimeter wavelengths. We present the results of several recent experiments and analyze the physical and technical limitations to arrange new radiating arrays.

This paper presents the results of numerical and experimental study of a Ka-band relativistic Cherenkov oscillator with average diameter of the slow-wave structure ${D} \approx \text {2.6}\lambda $ . ( $\lambda $ is a wavelength). The combined mode selection including the diffraction loss in the electron diode was applied. The high-current accelerator SINUS-200 provided the thin-walled annular electron beam in the range of voltages 350–420 kV and currents of 2.9–3.8 kA at pulsewidth of 10 ns. The generation of 2.5–3-ns pulses at the central frequency 36.4–36.8-GHz and 400–600-MW output microwave peak power was realized. The corresponding efficiency of 42% ± 5% in power conversion has been obtained.

The paper presents research results on enhancing the peak power of microwave pulses with sub- and nanosecond length using a backward-wave oscillator (BWO) operating at 29 GHz frequency and possessing a reproducible phase structure. Experiments are conducted in two modes on a high-current electron accelerator with the required electron beam power. In the first (superradiation) mode, which utilizes the elongated slow-wave structure, the BWO peak power is 3 GW at 180 ns pulse duration (full width at halfmaximum, FWHM). In the second (quasi-stationary) mode, the BWO peak power reaches 600 MW at ~2 ns pulse duration (FWHM). The phase spread from pulse to pulse can vary from units to several tens of percent in a nanosecond pulse mode. The experiments do not show any influence of microwave breakdown on the BWO power generation and radiation pulse duration.

We present the results of a comparative study of the shock-wave hardening regularities and mechanisms revealed for bulk (thickness h = 6 and 9.3 mm) targets made of austenitic 304L stainless steel and Hadfield steel. A high-current relativistic electron beam (45 ns, 1.35 MeV, 34 GW/cm 2 ) produced by the SINUS-7 accelerator was used for generation of a shock wave. It is revealed by 2D-computer simulation for type 304 steel that the direct ablation of the target material leads to generation of shock wave with duration of ∼0.1 μs and amplitude of ∼20 GPa, and the strain rate during its direct propagation and reflection from the free rear surface decreases from ∼2 down to ∼0.4 μs −1 . It is found experimentally that in the absence of a rear spall ( h = 9.3 mm) the shock-wave loading of both steels leads to formation of three hardened layers: a front layer with a maximum microhardness at a depth of 0.5–1 mm from the bottom of ablation hole, which is in a reasonable agreement with the predictions of the heat-transfer calculations, as well as intermediate and rear-side layers. In case of 304L stainless steel, the depth distributions of microhardness and fraction of twinned grains are consistent with each other, while in the Hadfield steel, the correlation is within the front and intermediate hardened layers only. It is shown by microstructural characterization and analysis of hardening mechanisms that in the case of 304L stainless steel, both front and rear-side hardening are significantly associated with the formation of new intra-phase boundaries by deformation twinning. In the Hadfield steel, unlike the 304L stainless steel, the unusual rear-side hardening is mainly due to increasing the dislocation density under submicrosecond single cycle of compression followed by tension with peak stress of ∼3 GPa.

The paper describes a study of a new relativistic microwave Cherenkov generator of millimeter wavelength range with the transverse dimension of the electrodynamic system D>2.5λ, where D is the average diameter of the slow wave structure, and λ is the radiation wavelength. The investigations were carried out with a high-current SINUS-200 electron accelerator at a voltage of 473 kV and an electron beam current of 3.8 kA. The use of several, complementing each other, mechanisms of suppression of parasitic waves provides stable microwave generation at a specified frequency of 36.4 GHz. The microwave power in the experiment 804 MW with 45% beam-to microwave power conversion.

The results of numerical and experimental investigations of the shock-wave induced spall fracture of bulk samples with thickness up to 10 mm made of 304L stainless steel irradiated by a nanosecond relativistic high-current electron beam with duration of $${\sim }$$ 45 ns, electron energy of 1.35 MeV, and peak power density of $$\hbox {34 GW/cm}^{2}$$ are presented. By a mathematical model developed for numerical simulation of the shock-wave dynamics, it was found that a quasi-planar shock wave with duration of $${\sim }0.2\,\upmu \hbox {s}$$ , and initial amplitude of 17 GPa was formed in the irradiated samples. The effects of orientation of $$\updelta $$ -ferrite interlayers in the austenitic matrix relative to the shock wave direction on the spall fracture were experimentally investigated. It was found that spallation was carried out by mixed ductile–brittle fracture. For the transversal orientation of $$\updelta $$ -ferrite, the contribution of a brittle fracture mode in the spallation is higher than that for the longitudinal orientation. In both cases, the spalled layer thickness increased almost linearly with the increase of the target thickness, which was in good agreement with literature data. By the comparison of experimental data with simulation results, it was revealed that the spall strength can be estimated as 6.1 GPa at strain rate $$0.48\,\upmu \hbox {s}^{-1}$$ and 3.4 GPa at strain rate 0.18 $$\upmu \hbox {s}^{-1}$$ , for samples with the longitudinal and transversal orientation of $$\updelta $$ -ferrites, respectively. The comparison of the obtained spall strength values with literature data is considered.

We demonstrate a source of high power nanosecond RF pulses based on gyromagnetic nonlinear transmission line. The source is designed to explore the exposure of different biological objects to strong RF fields in an air filled rectangular waveguide loaded onto ethanol RF load. The RF pulse amplitude can be varied by 52 dB, reaching a maximum value of nearly 40 kV/cm and decreasing to tens of V/cm. The RF pulse amplitude is controlled by decreasing the incident pulse amplitude from the high voltage driver. The duration of RF pulses lies in the range from 4 to 25 ns and the frequency from 0.6 to 1.0 GHz.

First version of relativistic BWO with TM 02 operating mode has been tested also in [1]. The cyclotron-resonance mode selection was used. In this case, because of requirement to the defined values of magnetic field and e-beam radius, the efficiency of oscillator was not very high (approximately 10%). Now, the different electrodynamic codes are available to optimize the geometry of Slow Wave Structure (SWS) and reflector for TM 02 mode with small re-emission to TM 01 . Then other techniques of mode selection such as the e-beam pre-modulation near the reflector [2], sectioning of SWS and diffractive losses at the coaxial magnetically-insolated diode can be used. So, refusing the cyclotron-type discrimination of TM 01 mode, we studied approaches of mode selection with higher magnetic field to increase the BWO efficiency, including the idea of self-modulated e-beam emission [3].

The results of experimental studies of different types of cathodes—carbon-epoxy rods, carbon-epoxy capillary, edged graphite, and metal-dielectric—under the application of high-voltage pulses with an amplitude of several hundreds of kV and pulse duration of several nanoseconds are presented. The best diode performance was achieved with the edged graphite and carbon-epoxy-based cathodes characterized by uniform and fast (

We demonstrate electronically controlled beam steering by high power RF pulses produced by two gyromagnetic nonlinear transmission lines (NLTLs) connected to a one high voltage driver. Each NLTL is capable of producing several ns RF pulses with peak power from 50 to 700 MW (6% standard deviation) at frequencies from 0.5 to 1.7 GHz (1% standard deviation) with 100 Hz repetition rate. Using a helix antenna allows irradiating of RF pulses with almost circular polarization and 350 MW maximum peak power, which corresponds to 350 kV effective potential of radiation. At the installation of two identical channels, we demonstrate the possibility of beam steering within ±15° in the horizontal plane by coherent RF pulses with circular polarization at 1.0 GHz center frequency. Fourfold increase in the power flux density for in-phase irradiation of RF pulses is confirmed by comparison with one-channel operation.