Evidence of the Frasnian Genundewa Event at the FZ 2 - FZ 3 boundary interval has been detected in the facies of the isolated carbonate platform in Subpolar Urals. The preserved traces of the Genundewa Event represent micritic microlaminated carbonates, which manifests a short-term deepening episode in an extremely shallow water background. From the onset of this deep- water deposition there is a dominance of Polygnathus, , Ancyrodella, , and Mesotaxis whereas in the underlying shallow water deposits, the genus Polygnathus clearly predominated. No specific features of the Genundewa Event were observed in the C-isotope record. The mean delta 13 C carb value is approximately 2 parts per thousand in the event interval. The onset of the Genundewa & IEcy;vent corresponds to the beginning of EuroAmerican IIb-2 cycle and is correlated with the base of the Sargaevian regional substage of the Urals and Russian Platform, as well as the base of Poland IC cycle. This correlation confirms the global character of this event.

In this paper, we studied the operability of various components of vacuum electronic devices manufactured using the novel chemical metallization of photopolymer 3D-printed structures technology (CMPS), which is being applied at the Institute of Applied Physics, Russian Academy of Sciences (IAP RAS), for operation from microwave to sub-terahertz ranges. The key feature of this production method is the 3D printing (SLA/DLP, MJM technologies) of products and their further metallization. The paper presents the main stages of the process of chemical copper plating of polymer bases in various electrodynamic systems with complex shapes. A significant difference in the geometry and operating conditions of the created elements forms certain approaches to their production, as described in this work. Experimental studies of the implemented microwave components were carried out up to 700 GHz in the “cold” measurements; some electrodynamic structures were examined under conditions of sub-gigawatt peak power; and complex-shaped electrodes with cooling channels were tested under a continuous high thermal load. The conducted research has demonstrated the high potential of the developed methods of additive manufacturing of microwave device components and the prospects for their successful application in the described areas.

A quasi-optical three-mirror pulse compressor with laser-driven GaAs switch was developed and experimentally tested. GaAs switch was activated by 532 nm laser with a pulse duration of about 100 ps and a pulse energy of about 50 mJ. Power gain of about 25 was obtained when compressing the output radiation of 170 GHz backward wave oscillator operating in a continuous wave mode, with an output power of about 10 mW.

The development of the microwave devices requires testing of many variants of microwave components. Therefore, the additive technologies allowing fast and non-expensive component fabrication is of great interest. To evaluate the performance of the 3D printed and metalized millimeter-wave elements, manufactured by chemical metallization of photopolymer-based structures technology (CMPS), single-mode rectangular waveguides were fabricated and measured at the frequencies from 26 to 110 GHz. The measurement results show that the parameters of 3D-printed waveguides are close to the parameters of fully-metallic components produced by conventional techniques. Since the ohmic losses are low in the Ka, W-band, a closed cavity was used for accurate losses evaluation.

The design of a technological complex for microwave processing of organic materials is proposed. The electrodynamic system of an oversized microwave reactor for low-temperature pyrolysis has been developed. The constructive elements of the complex that allow its continuous failure-free operation in conditions of high radiation intensity are described. Based on the prototype of the elaborated reactor, model experiments on microwave pyrolysis of peat were carried out. The elemental composition of the solid fraction was analyzed during the conducted experiments. The possibility of the efficiency enhancement of the proposed processing method and potential applications of the novel technology are discussed.

In this report, we present the first results of testing a new technological gyrotron at the first cyclotron harmonic with a radiation frequency of 28 GHz and a power of over 20 kW. The generation efficiency reaches 55% at a power level of 6 kW without a system for recuperating the residual electron energy. The efficiency of the entire installation is above 35% in the mode of maximum radiation power, which is achieved by using a magnetically shielded oil-cooled solenoid. The results obtained confirm the operability of the developed electron-optical system under conditions of a sharp drop in the magnetic field of the main solenoid outside the magnet bore. Experimental data are consistent with the results of numerical simulation. This is to hope for the implementation of generators up to the W frequency band using the same magnetic system and high-voltage power supplies.

Quasi-optical microwave pulse compressor with laser-driven GaAs switch has been designed and developed. The compressor is based on three-mirror travelling wave resonator and a disk-shaped GaAs wafer, which serves as a switch activated by a picosecond 532 nm laser with pulse energy up to 50 mJ. The wafer with a diameter of 150 mm and a thickness of 0.6 mm is installed at Brewster's angle to the operating wave traveling in the resonator, that almost eliminates loss corresponding to parasitic reflection from the wafer. Resonator is thermostabilized in order to maintain its resonant frequency with precision of 0.5 MHz, which is less than the resonance bandwidth amounted to 2.7 MHz for the operating mode with resonant frequency of 170 GHz and the Q-factor of 6*10 4 . Stabilization of temperature is provided by water circulating in channels inside the resonator base. According to results of preliminary experiments with GaAs switch, in the developed compressor a formation of nanosecond and sub-nanosecond output microwave pulses with compression ratio of about 40 is achievable. For the input pulses produced by 170 GHz, 1 MW gyrotron, maximum power of output compressed microwave pulses is expected to be of about 40 MW. According to our estimations, this level of output radiation pulse power will not lead to development of surface microwave discharge at any element of compressor resonator in vacuum conditions.

The possibility of using additive technologies for the manufacture of elements of the electrodynamic system is studied in this paper. The application of the systems for microwave polymerization of liquid monomers is considered. A gyrotron with an operating radiation frequency of 263 GHz and a maximum continuous power of up to 1 kW was used as a radiation source. As a result of the work, the electrodynamic system was optimized and the uniformity of heating of monomeric precursors was increased (the temperature deviation was less than 10%).

Formation of sub-nanosecond and nanosecond scale microwave pulses from CW 170 GHz BWO has been experimentally demonstrated using quasi-optical GaAs switch with photoconductivity induced by both femtosecond 800 nm and picosecond 532 nm lasers. It has been shown that full duration at half maximum of the microwave pulses can be controlled by the energy of laser pulses in the range from sub-ns to a few nanoseconds.

To cover the so-called terahertz gap in powerful sources of coherent electromagnetic waves, a second-harmonic gyrotron operating in a 10 T liquid helium-free superconducting magnet has been designed, manufactured, and tested. With an operating voltage of 15 kV and a beam current of 0.6 A, the gyrotron generated coherent continuous-wave radiation at a frequency of 0.526 Terahertz with an output power of 250 Watts and an efficiency of 2.7%.

For the sub-THz range, a method for studying the electrodynamic characteristics of organic materials – caustobiolithes-is developed on the basis of a resonator spectrometer. In the frequency range 110 ÷ 260 GHz, the dielectric parameters (refractive index n and tanδ) of peat powders after its microwave processing in the process of «soft» pyrolysis, as well as core sections of oil-containing rock, were studied. The influence of natural humidity on the dielectric parameters of the samples is considered. The reasons for the spread of measurement results, which is observed in these materials and is their specific feature, are discussed

A design of a tunable notch filter based on prismatic and pyramidal resonators is proposed. In Ka frequency band, two samples of the filter with a prismatic resonator were manufactured, one of them by mechanical processing, and another using polymer 3D printing technology, followed by surface metallization. A good agreement was shown between simulated and measured characteristics of the fabricated filter samples, including a 20% stopband tuning. The attenuation of the single-cavity Ka band notch filter at the central frequency of stopband was -25 dB. Numerical simulations showed that when the number of resonators is increased to four, the attenuation increased to -60 dB in the absence of parasitic stopbands in the frequency range from 26 to 47 GHz. For a three-cavity filter with a pyramidal cavity in the numerical simulation, attenuation of -92 dB at a frequency of 240 GHz was obtained, which makes this filter attractive for plasma diagnostics systems in a promising prototype of an industrial fusion reactor of the next generation (DEMO).

Currently, there is a debate about the age relations of the new Cristatisporites deliquescens Palynozone with respect to the existing miospore and conodont zonations. The new zone occupies a level between the Cristatisporites pseudodeliquescens and Geminospora semilucensis - Perotrilites donensis zones in the regional scheme of the Devonian palynostratigraphic zonation. The lower part of the Cristatisporites deliquescens Palynozone corresponds to the Ancyrodella rotundiloba soluta conodont Zone. Spores, conodonts, and ostracodes characteristic for this new biostratigraphic interval are discussed.