The artificial neuron proposed earlier for use in superconducting neural networks is experimentally studied. The fabricated sample is a single-junction interferometer, part of the circuit of which is shunted by an additional inductance, which is also used to generate an output signal. A technological process has been developed and tested to fabricate a neuron in the form of a multilayer thin-film structure over a thick superconducting screen. The transfer function of the fabricated sample, which contains sigmoid and linear components, is experimentally measured. A theoretical model is developed to describe the relation between input and output signals in a practical superconducting neuron. The derived equations are shown to approximate experimental curves at a high level of accuracy. The linear component of the transfer function is shown to be related to the direct transmission of an input signal to a measuring circuit. Possible ways for improving the design of the sigma neuron are considered.

Different regimes of electromagnetic signal transmission through heterostructures formed by a sequence of conducting and non-conducting layers are discussed for various ratios between the frequency of radiation and the transport frequency of electron scattering in the conducting layers. Possibility to increase the efficiency of detecting or filtering electromagnetic radiation in a wide range of frequency range (from subTHz to far IR) in such structures is analyzed.

We discuss the detection of broadband radiation in the terahertz frequency range by a bolometric method using heterostructures consisting of a sequence of conducting and dielectric layers of doped and undoped semiconductors (gallium arsenide, germanium). This structure forms a photonic crystal with allowed and forbidden bands (absorption and transmission ranges). By selecting the thicknesses of the conductive and non-conductive layers and the doping levels, it is possible to form spectral intervals of effective absorption, which allows detecting pulses in the frequency range >10^12 Hz with a spectral width of the order of the carrier frequency.

The effect of electronic properties of substituents in the reactants on the [4+2]-cycloaddition of 3-vinyl-chromen-4-ones (dienes) and N-vinylpyrrolidines (dienophiles) has been studied. The conditions determining the formation of 4,4a-dihydroxanthones or benzophenones as the major products have been found. The aromatization of 4,4a-dihydroxanthones via pyran ring opening has been interpreted by quantum chemical calculations. A wide series of new 4,4a-dihydroxanthone and benzophenone derivatives have been isolated.

An analytical approach that makes it possible to reconstruct the current–phase relation (CPR) in Josephson structures included in one of the arms of a two-junction superconducting quantum interference device (SQUID), where the second junction has a significantly higher critical current and a known (sinusoidal) CPR, has been developed. The developed methods of analytical and numerical studies of current–flow transformations in two-junction SQUIDs make it possible to reconstruct the CPR of a junction with a low critical current taking into account both the existence of the self-inductance of the interferometer contour and a possible asymmetry in the supply current system. The efficiency of this approach has been confirmed by the experimental study of niobium–aluminum/aluminum oxide–niobium test structures with the known CPR.

Получены новые 4-гидрокси-6H-оксазин-6-оны, содержащие в положении 2 нитрофурильный и нитротиофеновый фрагменты. Взаимодействием этих оксазинов с моно- (этанол) и бинуклеофильными (фенилгидразин) реагентами синтезированы новые производные нитрофурана и тиофена. Показано, что синтезированные соединения обладают выраженным бактерицидным эффектом в отношении золотистого стафилококка и, в ряде случаев, кишечной палочки.

A series of new 4-hydroxy-6H-oxazin-6-ones containing 2-(5-nitrofuranyl) and 2-(5-nitrothienyl) moieties were obtained. New nitrofuran and thiophene derivatives were synthesized by reacting these oxazines with mono- (EtOH) and dinucleophiles (phenylhydrazine). It was established that the synthesized compounds possessed pronounced bactericidal activity against Staphylococcus aureus and, in some cases, Escherichia coli strains.

4-Hydroxy-6H-1,3-oxazin-6-ones containing a 3-vinylchromone fragment in the 2-position were synthesized. The direction of their reactions with hydrazine hydrate was found to depend on the solvent nature. The reaction in protic solvents (methanol, acetic acid) resulted in recyclization of both oxazine ring to 1,2,4-triazole and pyranone ring to pyrazole. Aprotic acetonitrile favored attack of hydrazine exclusively on the oxazine ring, while the 3-vinylchromone fragment remained intact.

This work presents a study of the detection principles for weak magnetic signals in the presence of thermal fluctuations using a superconductor ballistic detector based on Josephson transmission lines. The importance of taking the relativistic aspect into account both in calculating the dynamics of the interaction between a fluxon and current inhomogeneity and in analyzing the influence of thermal fluctuations on this dynamics, is shown. Optimization of detector parameters such as the bias current and energy dissipation is presented to maximize the signal-to-noise ratio.