Electromagnetic Oscillations Research Articles

Implementation of NATO standards to improve the electromagnetic immunity and compatibility of equipment of the critical infrastructure objects

Ensuring that domestic technical equipment meets modern safety and reliability requirements in accordance with NATO standards is a pressing problem in Ukraine. Without metrological support for testing the electromagnetic compatibility and immunity to powerful electromagnetic fields of natural and artificial origin, it is impossible to ensure reliable and safe use of modern electronic, electroenergetics and electric equipment in critical infrastructure facilities.
 The paper presents the metrological traceability paths of the state measurement standards in the field of electromagnetic measurements, established at the NSC “Institute of Metrology”, to the SI units. The results of the research on the measurement standard of the electromagnetic field strength unit in the frequency range from 0.01 MHz to 43 GHz (NDETU EM-05-2021), established at the NSC “Institute of Metrology”, are described. The connection of the NDETU EM-05-2021 measurement standard with the measurement standards of the power unit of electromagnetic oscillations in coaxial and waveguide transmission lines and the standard of AC electric voltage is demonstrated.
 The lists of tests in accordance with the AESTR-500 standard, which are supported by the measurement standards of the NSC “Institute of Metrology”, and the equipment that can be calibrated by the national measurement standards are given. The examples of tests for electromagnetic compatibility carried out in the testing centre of the State Enterprise “Kharkivstandartmetrologiya” are provided.
 Based on the results of the developed statistical models at the Research and Design Institute “Molniya” for predicting the vulnerability to electromagnetic effects of atmospheric phenomena on critical infrastructure facilities, the examples of the distribution of lines of the equal potential (in kilovolts) on the ground surface in the short circuit mode and the distributions of probability density of lightning strikes are presented. The distributions of the equal potential lines on the ground surface in the short-circuit mode of high-voltage substations are modelled based on calculations.

Effect of temperature oscillations on kinetic inductance and depairing in thin and narrow superconducting nanowire resonators

Recent experiments have demonstrated a method for extracting the depairing current of nanowires fabricated from thin-film dirty superconductors using the AC response of DC-current biased resonators. While the existing theoretical model for understanding this response, developed by Clem and Kogan, provides agreement with Eilenberger-Usadel theory at low temperatures, there is a systematic and substantial deviation from theory at elevated temperatures. We propose that the DC bias in the presence of electromagnetic oscillations leads to Joule heating in the superconductor. This heating, combined with the strong electron-electron scattering in these heavily disordered materials, leads to oscillations in the effective temperature of the superconductor which alter the kinetic inductance. In this work, we derive the expression for the shift in kinetic inductance in the presence of a bias current and demonstrate that this model provides a significantly improved agreement between experiment and theory.

Adaptive Band-Pass Filter and VMD-Esprit Based Multi-Mode Monitoring Method for Broadband Electromagnetic Oscillation in “Double High” Power Systems

With the development of new power systems with high proportions of renewable energy and high proportions of power electronics equipment, the influence of broadband electromagnetic oscillations in power systems is becoming more and more significant. In order to better grasp the dynamic characteristics of broadband oscillations, a new adaptive band-pass filter and VMD-Esprit based multi-modal monitoring method is proposed for broadband electromagnetic oscillation in “double high” power systems. First, based on the mode frequency and amplitude information provided by FFT mode detection, the proposed adaptive band-pass filter adaptively sets the center frequency, bandwidth, and other parameters and extracts or separates the voltage/current signal in each frequency band. Second, the filtered signals are corrected and compensated, and then the VMD modal decomposition of each frequency band signal is combined with Esprit for parameter identification so as to obtain the waveform and parameter information of each mode. Finally, the separation, correction, and parameter identification of multi-mode broadband oscillation waveforms are carried out. The experimental results show that frequency division processing can reduce the computation and improve real-time performance. In the processing of signals in the frequency band, the center frequency, bandwidth, and other parameters can be adjusted adaptively under different conditions of single-mode composition or multi-mode composition, which improves the accuracy of VMD decomposition and increases the flexibility of signal processing. Meanwhile, it overcomes the defects such as the inaccuracy of traditional mode recognition, which provides a new idea for broadband electromagnetic oscillation analysis.

Электромагнитные УНЧ/КНЧ-колебания, вызванные извержением вулкана Тонга

The eruption of the Tonga volcano on January 13 and 15, 2022 and related intense lightning activity led to the excitation of a number of specific electromagnetic oscillations in different frequency ranges. We examine properties of these oscillations, using data from magnetometers of various types located in Kamchatka and in the Pacific region. We confirmed that there might have been a geomagnetic response to the formation of an acoustic resonance between the Earth surface and the ionosphere: localized harmonic oscillations with a frequency 3.5–4.0 mHz, which lasted for ~1.5 hr, were detected ~15 min after the beginning of the eruption at distance of ~800 km. An increase was observed in the intensity of the Schumann resonance at stations in the Far East. Broadband emission stimulated by intense volcanic lightning was detected to occur in the Pc1 range (2–5 Hz). The emission presumably results from the excitation of the magnetosonic waveguide in the upper ionosphere by lightning activity.

Электромагнитные УНЧ/КНЧ-колебания, вызванные извержением вулкана

The eruption of the Tonga volcano on January 13 and 15, 2022 and related intense lightning activity led to the excitation of a number of specific electromagnetic oscillations in different frequency ranges. We examine properties of these oscillations, using data from magnetometers of various types located in Kamchatka and in the Pacific region. We confirmed that there might have been a geomagnetic response to the formation of an acoustic resonance between the Earth surface and the ionosphere: localized harmonic oscillations with a frequency 3.5–4.0 mHz, which lasted for ~1.5 hr, were detected ~15 min after the beginning of the eruption at distance of ~800 km. An increase was observed in the intensity of the Schumann resonance at stations in the Far East. Broadband emission stimulated by intense volcanic lightning was detected to occur in the Pc1 range (2–5 Hz). The emission presumably results from the excitation of the magnetosonic waveguide in the upper ionosphere by lightning activity.

Achieving polycrystalline transformation and microstructural segregation reduction of nickel-based single crystal super-alloys by ultrasonic pulse arc welding

The sub-grains coarsening and low melting point eutectic are the internal causes of cracking of single crystal super-alloys in welding. Aiming to overcome two internal causes, in this paper, the effect of ultrasonic pulse arc welding on the grains, sub-grains and the precipitations of single crystal super-alloys (IN738) has been comprehensively studied, and the microstructure evolution of IN738 in ultrasonic pulse arc welding has been systematically revealed. The results show that (1) the combined effect of ultrasonic vibration and electromagnetic oscillation not only realizes the synchronous refinement of grains and sub-grains in WMZ (weld metal zone), and the polycrystalline transformation of single crystal super-alloys. A novel 3D schematic model of sub-grains is established to evaluate the size and orientation of sub-grains in 3D direction. (2) The ultrasonic vibration and electromagnetic field induced by ultrasonic pulse current can effectively reduce the microstructural segregation of welds. With the increase of ultrasonic pulse frequency, the size and volume fraction of harmful precipitations (η + δ eutectic, mixed eutectic and MC carbides) decrease greatly, especially the morphology and distribution characteristics of γ′ in HAZ (heat affected zone). Thanks to the above outstanding advantages, ultrasonic pulse arc welding has great application value in single crystal super-alloys.

INFLUENCE OF ELECTROMAGNETIC RADIATION ON RESISTANCE OF SEMICONDUCTOR DEVICES

The subject matter is the processes of analysis and mechanisms of appearance of instabilities of natural vibrations of semiconductor structures., due to their interaction with flows of charged particles under the influence of external electromagnetic radiation. It is shown that the influence of pulsed electromagnetic radiation is accompanied by the appearance of currents in the conductive elements of products that are capable of exciting natural oscillations of semiconductor components and are the cause of failures of radio products. The aim is to develop the theory of collisionless damping of surface polaritons in the classical approximation, as well as to study the mechanisms of collisionless damping of surface plasmons at the boundaries of semiconductor components of radio products under conditions when the temperature of carriers of conducting solids is much lower than the plasmon energy (quantum approximation). The objectives are: a kinetic equation describing the change in the number of surface plasmons as a result of their interaction with conduction electrons; obtaining its solution, which determine the decrement of oscillations and the power of spontaneous emission of particles. The methods used are: a method of successive approximations for solving the kinetic equations of the charged particle flux - semiconductor structure system within the framework of the quantum approach, when the interaction of waves and particles is in the nature of random collisions and is described by the method of secondary quantization of the system (representation of occupation numbers). The following results are obtained: Expressions are obtained for the decrements of surface plasmons in the presence of an infinitely high and infinitely small potential barrier at the interface between media. A kinetic equation is obtained that describes the change in the number surface plasmons as a result of their interaction with conduction electrons; his decisions are given, which determine oscillation decrement. Expressions are obtained for the decrements of surface plasmons at presence of infinitely high and infinitely small potential barrier at the interface between A physical model of the occurrence of reversible failures (effects induced by electromagnetic radiation currents per volt - ampere characteristics of semiconductor devices). The ranges of parameters of the external electromagnetic radiation at which this physical model is realized. Conclusion. Calculated relations are obtained that relate the parameters of semi-conductor structures: the concentration of free carriers, permittivity, carrier temperature with the value oscillation decrement in the classical and quantum approximations. The comparative analysis of quantitative estimates of the increments of oscillation instabilities carried out in the work makes it possible to solve the problems of optimizing the operating characteristics of active devices in the microwave range. The results of the work can be used in the development of microwave devices designed to amplify, generate and convert electromagnetic oscillations in the millimeter and submillimeter ranges.

Stability Region Analysis of Grid-Tied Voltage Sourced Converters Using Variable Operating Point Impedance Model

The interactions between voltage-sourced converters (VSCs) and the grid may trigger unstable electromagnetic oscillations. Impedance model-based analysis is widely utilized for investigating such emerging stability issues, mainly due to its capability to model black/gray-box VSC-based devices without complete knowledge of their internal control structures and parameters. It is well known that the characteristics of the triggered oscillation are determined by the operating conditions. However, most of the existing impedance-based methods are operating point specific, i.e., the impedance model of VSC-based devices has to be re-measured upon variations in the operating point. Thus, it is quite cumbersome and hectic to reconstruct the impedance model of a VSC-based device for all possible operating points and establish a stable or unstable region. This paper develops a novel method to determine the oscillatory stability region of a grid-tied VSC. First, a variable-operating point impedance model (VOPIM) of a VSC is derived. Next, the VOPIM is used to determine the frequency and damping of the oscillation modes for varying operating points. Finally, the oscillatory stability region is determined according to the damping of each oscillation mode. The accuracy of the oscillatory stability region and the effectiveness of the proposed method is verified through time-domain electromagnetic simulations.

Reactive Current Distribution Strategy of DFIG's RSC and GSC Considering Electromagnetic Stress and Grid Codes Requirement

The doubly fed induction generator (DFIG) based wind turbines are required to output positive- and negative-sequence reactive currents during asymmetric grid conditions by the latest grid codes. However, the electromagnetic stress, related to the reactive current settings of both the rotor- and grid-side converters (RSC and GSC) of the DFIG, will be aggravated. That is the oscillations in both the electromagnetic torque and DC-link voltage would be boosted up. To tackle such problem, the positive- and negative-sequence reactive currents need to be carefully distributed, so as to suppress electromagnetic oscillations while fulfilling the grid code requirements. To do so, in this paper, the influence mechanism of the positive- and negative-sequence reactive currents on the electromagnetic stress is firstly studied. Then, a coordinated reactive current distribution strategy, considering the electromagnetic stress, the grid code requirements, and the converters’ capacity limit, is presented. Finally, electromagnetic simulations are conducted to validate the effectiveness of the proposed method.

Influence of electromagnetic waves on the penetration of an antiseptic in the dentine of the tooth root in experimental conditions

Aims. To analyse the impact of electromagnetic oscillations in the sound range on diffusion the 3.25 % solution of sodium hypochlorite in the dentine of the tooth root.Materials and methods. A pilot study on diffusion of 3.25% of solution of sodium hypochlorite with dye fuchsine red was executed on 100 extracted teeth of the person. The control group was made by 40 teeth, the introduction of an antiseptic was conducted without use of sound waves. The main group of 60 teeth was divided into 3 subgroups. For the purpose of intensifying of the penetration of an antiseptic in each subgroup, electromagnetic oscillations (frequency range around 20,000 Hz) were applied with exposition time respectively 1 minute, 2 minutes, 3 minutes.Results. Application of sound waves in the canal of a tooth root led to augmentation of penetration of an antiseptic in the system of dentinal canaliculus and microchannels of the tooth root dentine.Conclusions. This process took place most effectively in single-root teeth when exposed to sound vibrations, smaller efficiency is revealed in multirooted teeth that indicates the difference in physical properties of the tissues of the various groups of the teeth.

Doubly Fed Induction Machine-Based DC Voltage Generator with Reduced Oscillations of Torque and Output Voltage

The doubly fed induction machine (DFIM)-based DC voltage generator is equipped with a stator-connected diode rectifier. The six-pulse diode rectifier as a nonlinear circuit introduces harmonics in the stator and rotor current and distorts the machine stator voltage, as well as the stator flux. This causes electromagnetic torque oscillations and instantaneous power components oscillations. The torque oscillations adversely impact the mechanical parts of the drive-train and oscillations of the p component of instantaneous power influence DC-bus voltage oscillations. The oscillations can be somewhat cancelled by control methods. However, cancellation of electromagnetic torque is not strictly coupled with cancellation of oscillations of the p component of instantaneous power. The paper presents an analysis of influence of the control methods aimed at a reduction of torque oscillations on the output voltage oscillations level in the stand-alone DFIM-based DC voltage generator. Field-oriented control FOC with current controllers and space vector modulation-based direct torque control DTC-SVM with flux module regulation have been compared with control in which electromagnetic torque is one of the commanded variables, whereas the second variable is the dot product of stator flux and rotor current space vectors. The contributions of this paper are the introduction of a new variable in the second control path in the DTC-SVM method instead of flux vector length and the proof that it can reduce torque and DC-bus voltage oscillations in the DFIG-DC system. Additionally, this paper reveals that for proper stator-to-rotor-turns ratio of a doubly fed machine necessary for reduction of the rotor converter power, lower DC-bus voltage can be obtained than is required for full realization rotor side voltage requested by rotor current controllers. This is the reason why, regardless of the control method, torque oscillations cannot be always fully cancelled, and a comparative study of the methods at these conditions has been conducted in simulation and in laboratory tests.

Full-Scale Electromagnetic Transient Modeling and Oscillation Suppression of a Wind Farm with SVG

With the gradual depletion of the earth’s resources and people’s attention to environmental issues, the access of renewable energy has been paid more and more attention by countries around the world. Wind is one of the pollution-free energy sources, and wind power generation is forming a boom in the world, because wind power generation does not need to use fuel, nor does it produce radiation or air pollution. The power of wind power generation is characterized by volatility and intermittence. When there is disturbance in the system, the wind farm is likely to oscillate and challenge the stability of the power grid. Therefore, the wind turbine generator must be connected to SVG system to realize dynamic reactive power compensation function, so as to ensure the stability of its operation in case of fault. In addition, the cause of wind turbine oscillation needs to be analyzed in detail to ensure its stability.

INVESTIGATION OF STRENGTH PROPERTIES OF RADIATION-MODIFIED POLYMER COATINGS

One of the methods for improving the properties of polymer coatings is radiation treatment. It is mainly carried out by ultraviolet rays and ionizing radiation. There are several types of ionizing radiation: radiation caused by deep changes in the electron shell and the nucleus of the atom and having the nature of electromagnetic oscillations, x-ray and γ-radiation; streams of charged particles that can have both positive and negative charges.

Essence of Photons and Dark Matters

What exactly are photons and dark matter? Modern physical theories do not explain them very well. In this paper, by extending the law of electromagnetic oscillation, the space particles and their operation law can also be obtained. The system of space particle theory is formed under the law of physics. The conclusion of the theory of space particles is quite consistent with many physical phenomena. There are no contradictions that can be found. According to the theory of space particles, there is an uneven space at the edge of an object, which has been proved by a series of experimental phenomena. The theory of space particles has revealed the essence of photons and dark matter. It has also revealed the relationship between space, mass, and energy. Space is a physical phenomenon.

Сходство механизмов возбуждения THz-излучения в магнитных наноконтактах и в наногетероструктуре с тяжелым металлом Мо

The modes of occurrence of Three-band electromagnetic oscillations during the flow of current in magnetic nanocontacts and in a heterogeneous Fe/Mo structure with a heavy metal nanofilm are compared, and the similarity of the dependences of the change in radiated power on the change in current in the region of radiation occurrence is established. Based on this, a conclusion is made about the identity of the processes of THz radiation formation in the structures under study and the possibility of spreading physical ideas about the excitation of THz radiation during spin injection by current in the case of a heterogeneous Fe/Mo structure with a heavy metal nanofilm.

Modeling of High-frequency Electromagnetic Oscillation for DC Fault in MMC-HVDC Systems

Modeling of High-frequency Electromagnetic Oscillation for DC Fault in MMC-HVDC Systems

Review on Model Based Design of Advanced Control Algorithms for Cogging Torque Reduction in Power Drive Systems

This review of the state of the art aims to collect the description and main research results in the field of development and validation of control algorithms with the main purpose to solve the problem of cogging torque and main sources of electromagnetic torque ripple. In particular, we focus on electric drives for advanced and modern mechatronic applications such as industrial automation, robotics, and automotive applications, with special emphasis on work that exploits model-based design. A great added value of this paper is to explicitly show the operational steps required for the model-based design design of optimized control algorithms for electric drives where it is necessary to make up for electromagnetic torque oscillations due to the main sources of ripple, particularly cogging torque. The ultimate goal of this paper is to provide researchers approaching this particular problem with a comprehensive collection of the most effective solutions reported in the state of the art and also a summary for effectively applying the model-based design methodology.

The activity of information in biomolecular systems: a fundamental explanation of holonomic brain theory

We wish to suggest a mechanism for binding intrinsic information based on an inter-cerebral superfast, spontaneous information pathway involving protein-protein interactions. Protons are convenient quantum objects for transferring bit units in a complex water medium like the brain. The phonon-polariton interaction in such a medium adds informational complexity involving complex protein interactions that are essential for the superfluid-like highway to enable the consciousness process to penetrate brain regions due to different regulated gene sets as opposed to single region-specific genes. Protein pathways in the cerebral cortices are connected in a single network of thousands of proteins. To understand the role of inter-cerebral communication, we postulate protonic currents in interfacial water crystal lattices result from phonon-polariton vibrations, which can lead in the presence of an electromagnetic field, to ultra-rapid communication where thermo-qubits, physical feelings, and protons that are convenient quantum objects for transferring bit units in a complex water medium. The relative equality between the frequencies of thermal oscillations due to the energy of the quasi-protonic movement about a closed loop and the frequencies of electromagnetic oscillations confirms the existence of quasi-polaritons. Phonon-polaritons are electromagnetic waves coupled to lattice vibrational modes. Still, when generated specifically by protons, they are referred to as phonon-coupled quasi-particles, i.e., providing a coupling with vibrational motions. We start from quasiparticles and move up the scale to biomolecular communication in subcellular, cellular and neuronal structures, leading to the negentropic entanglement of multiscale ‘bits’ of information. Espousing quantum potential chemistry, the interdependence of intrinsic information on the negative gain in the steady-state represents the mesoscopic aggregate of the microscopic random quantum-thermal fluctuations expressed through a negentropically derived, temperature-dependent, dissipative quantum potential energy. The latter depends on the time derivative of the spread function and temperature, which fundamentally explains the holonomic brain theory.

Electromagnetic interactions in regulations of cell behaviors and morphogenesis.

Emerging evidence indicates that the cellular electromagnetic field regulates the fundamental physics of cell biology. The electromagnetic oscillations and synchronization of biomolecules triggered by the internal and external pulses serve as the physical basis of the cellular electromagnetic field. Recent studies have indicated that centrosomes, a small organelle in eukaryotic cells that organize spindle microtubules during mitosis, also function as a nano-electronic generator in cells. Additionally, cellular electromagnetic fields are defined by cell types and correlated to the epigenetic status of the cell. These interactions between tissue-specific electromagnetic fields and chromatin fibers of progenitor cells regulate cell differentiation and organ sizes. The same mechanism is implicated in the regulation of tissue homeostasis and morphological adaptation in evolution. Intercellular electromagnetic interactions also regulate the migratory behaviors of cells and the morphogenesis programs of neural circuits. The process is closely linked with centrosome function and intercellular communication of the electromagnetic fields of microtubule filaments. Clearly, more and more evidence has shown the importance of cellular electromagnetic fields in regulatory processes. Furthermore, a detailed understanding of the physical nature of the inter- and intracellular electromagnetic interactions will better our understanding of fundamental biological questions and a wide range of biological processes.

Contactless excitation of acoustic resonance in insulating wafers

Contactless excitation and detection of high harmonic acoustic overtones in a thin insulator single crystal are described using radio frequency spectroscopy techniques. Single crystal [001] silicon wafer samples were investigated, one side covered with a Nb thin film, the common starting point for the fabrication of quantum devices. The coupling between electromagnetic signals and mechanical oscillation is achieved from the Lorentz force generated by an external magnetic field. This method is suitable for any sample with a metallic surface or covered with a thin metal film. High resolution measurements of the temperature dependence of the sound velocity and elastic constants of silicon are reported and compared with known results.