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One of the key elements for modern microwave circuits is a delay line, which is widely utilized for the signal generation as well as processing. Spin-wave delay lines based on ferrite films provide a high delay time and small dimensions. Typically, the performance characteristics of such lines are tuned by the variation of an externally applied magnetic field characterized by some drawbacks. The phenomenon of a metal–insulator transition (MIT) in the phase change materials permits to improve the performance characteristics of the spin-wave delay lines. In particular, this concept allows to reduce the power consumption and improve the control speed of a delay time. Aim. Development of a tunable spin-wave delay line based on ferrite and vanadium dioxide films, as well as the study of its performance characteristics. Methods. Experimental investigations were carried out for the delay line composed of the yttrium iron garnet (YIG) and vanadium dioxide (VO2) films. The ferrite waveguide was fabricated from a single-crystal YIG film grown on a gallium gadolinium garnet substrate. A vanadium dioxide film was formed on a silicon dioxide substrate by DC reactive magnetron sputtering. The microwave measurements were carried out using the vector network analyzer R&S®R ZVA40. Results. It was shown that heating of the VO2 film induces a sufficient drop of its resistance that causes the transformation of the spin-wave dispersion characteristic. This leads to the decrease in the group velocity of the propagating waves providing a growth of a delay time. Namely, experimental structure of 5-mm length offers a tunable time delay range from 130 up to 150 ns at the operating frequency of 4.33 GHz. Conclusion. A proof-of-principle for the MIT control of the delay time composed on the YIG-VO2 structure has been presented. It was shown that a switch of VO2 film from the isolating into conducting state produces a 15% change in the delay time. The considered microwave delay lines look favorable for applications as a complimentary part to the traditional approach for general computing and microwave signal processing.

The object of the study is the hydrological and ecological characteristics of the springs of the Chuvash Republic. The springs of the region are of great economic importance. They are used for household and drinking water supply, for recreation and protection of unique landscapes. Intensive development and lack of improvement measures have led to the fact that the water quality in the springs is decreasing. The landscapes of the surrounding territories are oppressed. The study of the state of the springs is carried out by expeditions. During the visits, the ecological state of the springs is described, water samples are taken for physico-chemical analysis. The recreational significance of the sources for the development of a set of measures to optimize economic development is also described. Most of the springs of the Chuvash Republic belong to low-flow freshwater sources with medium water hardness. When moving from north to south, an increase in hardness and mineralization is observed. The flow velocity is the highest for alluvial deposits. The sources of the region belong to the following types: household and drinking, cultural and recreational and protected. All the studied springs perform an economic and drinking role. Sources related to protected sites – specially protected areas - have the greatest recreational value (very high level). The cultural and recreational role is to create fonts, conduct excursions to the springs. 75% of the springs are used daily. There are seasonally used and abandoned springs. To develop a program for optimizing the economic use of springs, it is proposed to compile a Register of springs of the Chuvash Republic. It will include the physico-chemical and landscape characteristics of the springs. Having such a database will allow you to determine the order and ways to solve problems related to the use of springs.

A numerical model describing a magnonic active ring oscillator (MARO) based on a microscopic spin-wave delay line is proposed. The model considers excitation, propagation, and reception of the magnetostatic surface waves in a yttrium iron garnet (YIG) magnetic film with a thickness in the nanometer range. The waves are excited and received with a microscopic coplanar antenna. We employed the model to analyze the influence of the YIG-film thickness and the distance between the antennas on the MARO performance characteristics. We showed that an increase in the delay time inserted by the delay line reduces the phase noise of the MARO and increases the auto-oscillation threshold. In addition, we found a relation between the auto-oscillation threshold, the thickness of the YIG film, and the distance between the antennas. The relation helps design miniature MAROs and suggests a way to reduce the phase noise of the device. The model predicts a phase noise level of −115 dBc/Hz at a 10 kHz offset from an oscillation frequency in the vicinity of 5 GHz for the MARO based on a 100 nm-thick YIG film and 56 μm of distance between the coplanar nano-antennas of the YIG-film based delay line. We believe that this is a clear way forward to microminiaturize the time-delay feedback microwave auto-oscillators. A further reduction in the phase noise down to −125 dBc/Hz at a 10 kHz offset is found in a model of cascaded connection of several microscopic spin-wave delay lines. [ABSTRACT FROM AUTHOR]

The goal of this work is to study the effect of the Natural Plant Complex (NPC) "White Pearl" on the yield and marketability of apples after long-term storage. The experiment comprised the following treatments: 1—control (without treatment); 2—foliar sprays (1% solution of "White Pearl Universal (WPU) Antifreeze" + 1% solution of "White Pearl (WP) Drip Ca + Mg"); and 3—foliar sprays (3% solution of "WPU Antifreeze" + 3% solution of "WP Drip Ca + Mg"). Foliar sprays with organomineral fertilizers (1% solution of "WPU Antifreeze" + 1% solution of "WP Drip Ca + Mg") significantly increased (by 1.8 times) the yield of the experimental apple cultivar compared to the control. After long-term storage, foliar sprays with a 1% solution and 3% solution of NPC "White Pearl" preparations significantly reduced scald damage to 'Sinap Orlovsky' apples compared to the control and increased the number of marketable 'Sinap Orlovsky' fruits by 1.4 and 1.2 times, respectively, but the 1% solution of organomineral fertilizers was more effective. The experiment that was conducted to evaluate the effect of organomineral fertilizers in apple plantations shows that they can potentially be used to supplement traditional apple cultivation technologies. [ABSTRACT FROM AUTHOR]

See the retraction notice BIO Web of Conferences 116, 00001 (2024), https://doi.org/10.1051/bioconf/202411600001

A theoretical model for numerical simulation of the nonlinear spin-wave transient processes in magnonic active-ring oscillators (MAROs) with variable gain has been developed. The model employs the formalism of the Landau–Ginzburg equation to describe the nonlinear propagation of spectrally narrow magnonic wave packets in a magnetic film. We show that the model allows one to simulate ring's operation above the self-generation threshold as a magnonic physical reservoir computer for which the control of ring gain is employed as a method of data input into the physical reservoir. Performance of the reservoir computer was evaluated by carrying out numerical simulations using the developed model. To this end, we simulated the completion of the short-term memory and the parity-check tasks by the model. We found that the simulation results are in good agreement with experimental data. This evidences that the constructed model can be used for investigating physics underlying the performance of the MARO as a physical reservoir computer and for reservoir optimization with the final goal of maximizing reservoir performance. [ABSTRACT FROM AUTHOR]

The present work focuses on the effect of vanadium dioxide (VO2) films exhibiting a metal–insulator transition (MIT) on the performance characteristics of the magnetic multilayers. It has been shown that the MIT provides a novel mechanism for controlling the microwave spin-wave dynamics in the yttrium iron garnet (YIG) films. In particular, the low and high levels of microwave attenuation of spin waves transmitted through the YIG–VO2 bilayer has been observed due to a variation of the VO2 conductivity within a narrow temperature range. This effect has been utilized to realize fully reconfigurable magnonic crystals composed of the thickness-modulated YIG and regular VO2 films. A promising functionality of the proposed waveguiding structures arises from a controllability of wave intensity, which provides an altering of the frequency response from an original band structure to a full rejection of spin waves. Numerical simulations taking into account both the YIG film saturation magnetization and the VO2 film conductivity have confirmed the experimentally observed spin-wave dynamics. An interest in ferrite–VO2 bilayers arises not only from possible practical applications but also from a variety of fundamental scientific problems devoted to the physics of wave phenomena in planar thin-film magnetic multilayers. [ABSTRACT FROM AUTHOR]

We developed a new approach to the fabrication of MEMS (Microelectromechanical system) substrates for gas sensors. This full screen-printing approach consists in the application of sacrificial material, which is solid at the near-room temperature of printing and becomes powder after firing of the elements of the sensor and, therefore, can be removed from under the suspended elements of the MEMS structure in an ultrasonic bath. The glass–ceramic MEMS is a cantilever structure equipped with a Pt-based microheater on the end edge with the sensing layer. Screen-printing provides cheap fabrication, robustness, and low power (~120 mW at 450 °C) for the sensing element. [ABSTRACT FROM AUTHOR]