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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.

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.

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 effective 1-s batch of 100-Hz pulse repetition rate mode of an X-band relativistic backward-wave oscillator with a resonance reflector (RBWO-RR) was realized using the “SINUS” pulse-periodic nanosecond accelerator allowing mechanically installed high voltage pulse length of 13 and 42 ns. Magnetic held about of 2 T was produced by two-section solenoid to transport the electron beam along RBWO-RR electrodynamic system. T M01 to T E11 mode converter connected to the oscillator output allowed Gaussian radiation pattern. The microwave oscillator allowed producing the microwave pulse length of 4.7 and 29 ns. The energy of the microwave pulse measured by the X-band aperture calorimeter was 1.4 or 6.3 J corresponding to the mentioned above microwave pulse length of 4.7 or 29 ns, respectively. That allowed estimations of the microwave peak power as high as 280 ± 30 MW and 210 ± 20 MW related to the pulse lengths. The efficiency of the oscillator was 23-25%. A possibility of the microwave pulse length fine tuning within 25 to 34 ns range in the “long pulse mode” by changing the solenoid magnetic held conhguration was shown.

A mathematical model for combustion of a propellant with a coolant taking into account the two-zone structure of the combustion front due to condensed- and gas-phase reactions was developed and examined. Formulas for the burning rate, reaction-zone temperature, and burning-rate sensitivity to internal and external parameters of the system were derived in analytical form. The burning rate was examined numerically as a function of pressure, the characteristic size of the system, component content, and thermodynamic and kinetic parameters. Recommendations are given on methods of obtaining particular ballistic properties by varying the initial parameters of the system.

The model of combustion of a composition consisting of a quasi-homogeneous composite propellant (matrix) and coolant particles is considered. The model is based on the leading role of exothermal decomposition of the matrix and on the cooling effect of the second component by virtue of transverse heat transfer between the components in the condensed and gas phases. Formulas for combustion characteristics (temperature, burning rate, its sensitivity to pressure, and initial temperature) are derived and analyzed. The calculated dependences of these characteristics on pressure, particle size, concentration, and thermal effects of decomposition of the components show that transitional regimes with a stronger dependence of the burning rate on pressure than that of the initial propellant are reached in a certain range of parameters. An algorithm is proposed, and a parametric identification of the model on the basis of experimental data is performed.

This article describes the principles of operation and the parameters of the SINUS setups designed at the Institute of High-Current Electronics, Siberian Division, Russian Academy of Science, over the period from 1990 to 2002. A characteristic feature of accelerators of the SINUS type is the use of coaxial forming lines (in particular, with a spiral central conductor) which are charged by a built-in Tesla transformer to produce the accelerating high-voltage pulses. This ensures a reasonable compactness and long lifetime of the setups.

Operation of explosive-emission cold cathodes made from various materials was studied at a large number of pulses at current densities of /spl sim/1.0/sup 4/ A/cm/sup 2/. The cathode voltage and the beam current were /spl sim/500 kV and 5 kA, respectively, with a pulsewidth of /spl sim/20 ns. At a small number of pulses (/spl les/10/sup 3/), cathodes of like geometry (even made from different materials) demonstrated similar emission properties. For most of the materials tested, with a large number of pulses (/spl ges/10/sup 3/), the current risetime increased to the fullwidth of the voltage pulse and the maximum current of the vacuum diode decreased. When using a graphite cathode, the maximum current remained invariant until 10/sup 8/ pulses. Mass losses were measured for a series of cathode materials. The results obtained offered the possibility to realize long-lived operation of an X-band relativistic backward-wave oscillator with an almost invariant output power of 350-400 MW during 10/sup 8/ pulses at a pulse repetition rate of 100-150 p.p.s.

Results from a study of a relativistic X-band backward-wave oscillator (RBWO) with 3-GW output microwave power are presented. The RBWO was driven by the high-current electron accelerator SINUS-7. The dependence of radiated microwave pulse duration on microwave power was obtained. Pulse shortening occurring at the higher power levels is probably attributable to explosive electron emission from the slow wave structure (SWS). An increase in the cross section of the electrodynamic structure seems to be a way to increase the microwave pulse duration. Experimental results from a moderately oversized X-band RBWO using a resonance reflector are described. This tube can be operated with a low external magnetic field.

We demonstrate a high power repetitive rf source using gyromagnetic nonlinear transmission line to produce rf oscillations. Saturated NiZn ferrites act as active nonlinear medium first sharpening the pumping high voltage nanosecond pulse and then radiating at central frequency of about 1 GHz: shock rise time excites gyromagnetic precession in ferrites forming damping rf oscillations. The optimal length of nonlinear transmission line was found to be of about 1 m. SINUS-200 high voltage driver with Tesla transformer incorporated into pulse forming line has been designed and fabricated to produce bursts of 1000 pulses with 200 Hz repetition rate. A band-pass filter and mode-converter have been designed to extract rf pulse from low-frequency component and to form TE(11) mode of circular waveguide with linear polarization. A wide-band horn antenna has been fabricated to form Gaussian distribution of radiation pattern. The peak value of electric field strength of a radiated pulse at the distance of 3.5 m away from antenna is measured to be 160 kV/m. The corresponding rf peak power of 260 MW was achieved.

We examine a microscopically inhomogeneous medium consisting of a homogeneous nonlinear viscoplastic matrix and a random set of rigid ellipsoidal inclusions of various sizes. A variant of the effective field method is used to calculate the macroscopic rheological constants of the medium.