External Electromagnetic Radiation Research Articles

Rotational magic conditions for ultracold molecules in the presence of Raman and Rayleigh scattering

Molecules have vibrational, rotational, spin-orbit and hyperfine degrees of freedom or quantum states, each of which responds in a unique fashion to external electromagnetic radiation. The control over superpositions of these quantum states is key to coherent manipulation of molecules. For example, the better the coherence time the longer quantum simulations can last. The important quantity for controlling an ultracold molecule with laser light is its complex-valued molecular dynamic polarizability. Its real part determines the tweezer or trapping potential as felt by the molecule, while its imaginary part limits the coherence time. Here, our study shows that efficient trapping of a molecule in its vibrational ground state can be achieved by selecting a laser frequency with a detuning on the order of tens of GHz relative to an electric-dipole-forbidden molecular transition. Close proximity to this nearly forbidden transition allows to create a sufficiently deep trapping potential for multiple rotational states without sacrificing coherence times among these states from Raman and Rayleigh scattering. In fact, we demonstrate that magic trapping conditions for multiple rotational states of the ultracold 23Na87Rb polar molecule can be created.

Incorporation of organic photochromic molecules in mesoporous silica materials: Synthesis and applications

Abstract The ability to control the function and structure of some promising nanosystems using an external stimulus is attractive research to develop programmable and reconfigurable intelligent nanomaterials. The focal point of this review is the silicon-based nanoporous materials, and particularly the mesoporous silica materials (MSMs) class (pore size: 2–50 nm), due to their important intrinsic properties, such as high surface area, highly ordered nanostructure, narrow pore size distribution, various dimensions (one-dimensional, two-dimensional, and three-dimensional), and easily functionable. One of the most essential organic components that can be incorporated in MSMs is organic photochromic molecules (OPMs), such as azobenzene, stilbene, dithienylethenes, and spiropyrans. OPMs can be incorporated into MSMs, to form photochromic mesoporous organosilica materials (PMOMs), in two different ways: physical (non-covalent immobilization) or chemical (covalent immobilization) binding. PMOMs are considered smart nanomaterials because they have the ability to undergo reversible changes in the solid state when exposed to an external electromagnetic radiation. PMOMs have been the subject of many research studies during the last decade due to their potential applications, especially as chemosensors. This review discusses the main families of OPMs, their incorporation into MSMs using different methods, and the applications of some PMOMs as chemosensors.

INFLUENCE OF PULSE ELECTROMAGNETIC RADIATION ON PERFORMANCE OF ELECTRIC RADIO PRODUCTS

The subject matter is the processes of analysis of the occurrence of reversible and irreversible failures of semiconductor devices under conditions of exposure to electromagnetic radiation. It is shown that the influence of pulsed electromagnetic radiation is accompanied by the emergence of currents in the conductive elements of products and the emergence of their internal fields. The mechanisms for the occurrence of instabilities of natural oscillations of semiconductor components of electrical and radio products, caused by their interaction with flows of charged particles, have been determined. The presence of instabilities of this kind has a significant impact on the spectral (operating) characteristics of electrical radio products. The results obtained in the work make it possible to assess the degree of influence of pulsed electromagnetic radiation on the operating (volt-ampere) characteristics of electrical radio products. The aim is a model of the mechanisms of the emergence and development of instabilities of natural oscillations of semiconductor structures, components of electrical radio products (communication equipment), in the presence of currents and voltages induced by pulsed electromagnetic radiation. The implementation of such a model is due to the possibility of transforming the energy of a flow of charged particles induced by external electromagnetic radiation into the energy of natural vibrations of a semiconductor structure, taking into account the properties of the structure itself (size, concentration of free carriers, permeability). The transformation of the energy of currents induced by electromagnetic radiation into natural vibrations of a semiconductor structure is determined by two effects (transition or Cherenkov radiation) depending on the location of the structure relative to the direction of the currents. The objectives are: the main electromagnetic effects affecting performance of electrical radio products (ERI) under exposure conditions external pulsed radiation and also indicates characteristic changes ERI parameters that determine their functional purpose, which are a consequence of these effects. The methods used are the method of successive approximations over a small parameter, which allows one to determine the spectrum of natural oscillations of a semiconductor device and the mode of their amplification (instability). The following results are obtained. The results of studies characterizing the malfunction of electrical radio products under conditions of exposure to third-party electromagnetic radiation are presented, as well as the main parameters characterizing the electromagnetic resistance of electronic devices to the effects of pulsed currents and voltages. The characteristic types of malfunctions of semiconductor devices (SCD), components of electronic components, in areas of irreversible and reversible failures, as well as the levels of intensities and currents of electric and magnetic fields affecting the SPD, separating the areas of reversible and irreversible failures, are given. Using the energy approach, a physical model of the occurrence of one of the types of reversible failures of the semiconductor element base (the appearance of S-shaped sections of currentvoltage characteristics) has been developed. This physical model makes it possible to determine the criteria for the electromagnetic resistance of a number of semiconductor devices to the effects of external pulsed radiation and also to obtain calculated ratios for assessing the degree of deviation of the operating characteristics of the PPP from the norm. Conclusion. Development of design relationships that determine the modes of amplification (generation) of oscillations of electrical radio products, making it possible to determine the degree of distortion of their current-voltage characteristics (reversible failures) and complete loss of performance (irreversible failures) depending on the parameters of external electromagnetic radiation. The results obtained in the work can be used in the development of amplifiers, generators and frequency converters operating in the millimeter and submillimeter range that are resistant to external electromagnetic radiation. Quantitative estimates of the criterion for reversible failures (instability increments) show that the amount of radiation energy lies within the sensitivity of modern submillimeter radiation receivers and is the cause of failures.

Complex firing activities and bifurcations in memristor-coupled Hindmarsh–Rose neuron

Due to the unique synaptic plasticity and memory effect, a memristor can not only mimic biological synapses but also characterize the influence of external electromagnetic radiation. In this paper, a ReLU-type non-ideal memristor with a simple structure is first coupled to a classical three-dimensional Hindmarsh–Rose neuron to describe the electromagnetic induction effect, which can show period-doubling, period-adding, and saddle-node bifurcations by varying the coupling strength of the memristor. Furthermore, complex discharge behaviors of the system, including bursting discharge and spiking discharge, are exhibited, and some coexisting discharge modes associated with initial values are also presented. Finally, an analog circuit scheme consuming fewer circuit components is designed, and it was found that the experimental results are consistent with the numerical results.

Energy controls wave propagation in a neural network with spatial stimuli

Nervous system has distinct anisotropy and some intrinsic biophysical properties enable neurons present various firing modes in neural activities. In presence of realistic electromagnetic fields, non-uniform radiation activates these neurons with energy diversity. By using a feasible model, energy function is obtained to predict the growth of synaptic connections of these neurons. Distribution of average value of the Hamilton energy function vs. intensity of noisy disturbance can predict the occurrence of coherence resonance, which the neural activities show high regularity by applying noisy disturbance with moderate intensity. From physical viewpoint, the average energy value has similar role average power for the neuron. Non-uniform spatial disturbance is applied and energy is injected into the neural network, statistical synchronization factor is calculated to predict the network synchronization stability and wave propagation. The intensity for field coupling is adaptively controlled by energy diversity between adjacent neurons. Local energy balance will terminate further growth of the coupling intensity; otherwise, heterogeneity is formed in the network due to energy diversity. Furthermore, memristive channel current is introduced into the neuron model for perceiving the effect of electromagnetic induction and radiation, and a memristive neuron is obtained. The circuit implement of memristive circuit depends on the connection to a magnetic flux-controlled memristor into the mentioned neural circuit in an additive branch circuit. The connection and activation of this memristive neural network are controlled under external spatial electromagnetic radiation by capturing enough field energy. Continuous energy collection and exchange generate energy diversity and synaptic connection is created to regulate the synchronous firing patterns and energy balance.

Memristive Autapse-Coupled Neuron Model With External Electromagnetic Radiation Effects

Thanks to their distinct synaptic plasticity and memory effects, memristors not only can mimic biological neuronal synapses but also can describe the influence of external electromagnetic radiation. This paper proposes a novel memristive autapse-coupled neuron model (MACNM) using a locally active memristor as an autapse and simultaneously introducing a flux-controlled piecewise-nonlinear memristor to describe the external electromagnetic radiation. Theoretical analysis and numerical simulation results show that the MACNM is able to generate multiple numbers of grid multi-scroll hidden attractors. Moreover, it can exhibit rich and complex hidden firing dynamics, including periodic spiking/bursting firing, chaotic spiking/bursting firing as well as firing patterns transition. In particular, hidden firing multistability of five coexisting homogeneous chaotic bursting firing patterns with different offsets along the boosting route is discovered, giving raise to the interesting phenomenon of hidden homogeneous multistability. Finally, a circuit is designed to verify the physical feasibility of the abundant electrical activities in the proposed MACNM.

Innovative technologies for strengthening of internal surfaces of suspension parts of heavy-loaded machines by laser and high-frequency induction methods

In the article innovative methods of surface hardening of internal surfaces of machine parts by laser and highfrequency induction heating are presented. The relevance of applying the methods of laser and induction hardening for the internal surfaces of heavily loaded parts of quarry equipment is proved. The results of modeling and calculation of thermal and electromagnetic fields under the influence of an external electromagnetic field and laser radiation beams are presented. The original design of a complex of equipment for processing the internal surfaces of suspension parts by external electromagnetic field is described. The optimal designs of inductors with magnetic circuits made of various materials are shown. The study of the structure and properties obtained on the internal surfaces of heavily loaded suspension parts of cars, line of the BelAZ company, treated according to the optimal modes of surface induction exposure is given. The developed original technology and equipment of laser surface hardening, which makes it possible to increase the wear resistance of heavily loaded parts, is described. Data on the implementation of research results at JSC “BELAZ” – the Management Company of the Holding “BELAZ-HOLDING” for processing a wide range of heavily loaded suspension parts are given.

Promising Smart Materials for Radioelectronics

The investigations of a multilayer material – a polymeric radio-transparent electrically conductive film of polyaniline with a concentration of 5, 10 and 50 % by weight on a radio-transparent fiberglass substrate were carried out. Such materials are multifunctional – the material itself has the required characteristics, but when it is exposed to external electromagnetic radiation, it provides shielding functions. Electrically conductive polymer samples (polyaniline film) deposited on a fiberglass substrate have low attenuation in the 8–12 GHz transparency band, low electromagnetic radiation reflection coefficient, high conductivity and performance characteristics, as well as manufacturability.

Patterns stability in cardiac tissue under spatial electromagnetic radiation

The electric activity in myocardial tissue is controlled by the target waves emitted from the sinoatrial node and then the Calcium flow is controlled to regulate the heartbeat. The occurrence of local defects can block the wave propagation in the cardiac tissue and then the heartbeat can be disturbed completely. During the electrophysiological activity including stochastic diffusion of intracellular ions and continuous exchange of extracellular ions along ion channel embedded in the cell membrane, electromagnetic induction occurs in the cardiac tissue and the involvement of external electromagnetic radiation can change the excitability and the neural activities. In this paper, based on a memristive cardiac tissue model by incorporating magnetic flux variable and induction current into the two-variable cardiac model for discerning cardiac excitation, spatial electromagnetic radiation is applied to investigate the stability and propagation of waves in the cardiac tissue. Wave propagation in the reaction-diffusion equations for cardiac tissue is approached by an equivalent diffusive neural network on square array after discretization. Local heterogeneity is produced by introducing diversity in initial value for inducing spiral seed, and stable spiral waves are developed as initial states, which represent tachycardia and arrhythmia in the cardiac tissue. It is found that symmetric spatial patterns can be controlled by the external electromagnetic radiation, in particular, nonlinear resonance is enhanced and specific spatial patterns are developed under noisy radiation.

A study protocol for investigating the effects of mobile phone-originated electromagnetic waves on thyroid gland and thyroid hormone activities in the brain

With widespread users across the globe, topic on the impact of mobile phone in particular regarding its electromagnetic wave radiation deserves a priority. Carcinogenic effects of the electromagnetic wave radiation have been suggested by multiple studies. Effects of the radiation are to involve thermal and non-thermal pathways. Among human organs, thyroid gland is susceptible to the radiation exposure due to its location being superficial and close to the radiation transmitter. Previous studies have indicated the correlation between the mobile phone radiation and thyroid dysfunctions. However, a conclusion that the electromagnetic wave radiation is the causative agent of the thyroid dysfunctions has not been reached. Most of the study are unable to remove the influence of the external electromagnetic wave radiation. Hence, this study aimed to perform an investigation with true experimental design using animal model in an anechoic chamber – an isolated chamber which could minimize the electromagnetic wave noise from the outside. In this article, we present the description of the anechoic chamber along with the research protocols. Parameters affecting the investigation, including signal frequencies inside the chamber and specific absorption rate are also measured.

Intracranial Cancer Detection by Mobile Phone Electromagnetic Radiation

Cancer is the topping cause of death only after ischemic heart disease in the world. Among cancers, brain tumors are generally one of the hardest to heal. And among the brain tumors, glioblastoma multiforme, which is a very aggressive intracranial cancer, has one of the highest mortality rates. These cancers are rather difficult to diagnose with the lack of manual diagnosis and very aggressive in their progression the disease, thus a later-stage diagnosis would not be much of a benefit. Therefore, medical doctors require advanced medical imaging techniques such as computed tomography and magnetic resonance imaging for intracranial tumors. The Covid-19 pandemic has caused a global lockdown and has put an enormous load on the medical system. Any similar pandemic would almost paralyze the medical system. In this study, the authors investigate the possibility of an early-stage detection of glioblastoma multiforme by use of mobile phone electromagnetic radiation. Since cancer tissue contains more blood vessels because of its intrinsic energy needs, external electromagnetic radiation would affect the cancer tissue faster than the normal tissue. The authors build the model by introducing a hypothetical ellipsoid cancer tissue into the IEEE phantom head SAR model. By applying two different levels of external electromagnetic exposure, the simulations seek to find a discriminatory temperature change, which can be detected externally.

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.

THE INFLUENCE OF A POTENTIAL BARRIER ON THE MECHANISMS OF EXCITATION OF OWN FLUCTUATIONS IN RADIO PRODUCTS IN CONDITIONS OF EXPOSURE TO ELECTROMAGNETIC RADIATION

The subject matter is the processes of analysis and the mechanisms of the emergence of their own fluctuations in the semiconductor complex electro -radio devices (communications equipment), if there are currents and voltages entrusted with pulsed electromagnetic radiation, the results obtained in the work of the potential barrier on the border of the semi -conductive structure on the border of the semiconductor (voltage ampere) characteristics of a electro -radio device. The aim is model of transforming the energy of the flow of charged particles, induced by external electromagnetic radiation, into the energy of its own fluctuations in the semiconductor structure, taking into account the properties of the structure itself (heterogeneity of potential at the border). The implementation of this model is due to the effect of transitional radiation of moving charges, when the particle flow crosses the boundary of the media section with various electromagnetic properties (dielectric permeability) and part of its energy is transformed into the energy of its own fluctuations in the semiconductor structure. The objectives are: mechanisms of the strengthening (instability) mode of semiconductor components of semiconductor devices under conditions of impulse electromagnetic radiation in the presence of a potential barrier on the boundary of the media of the media. The methods used are the method of theory of small disturbances, which allows you to determine the spectrum of the own vibrations of the system: the current fluctuations of the semiconductor device in electromagnetic radiation. The following results are obtained: The interaction of surface plasmons with the flow was considered charged particles in the presence of a potential barrier based on energy principle. Kinetic equations have been obtained that determine the change in the number superficial plasmons, expressions for the increments of their instability with taking into account the size of a potential barrier on the border, which leads to the appearance of a beam reflected from the border. The results of the work allow you to take into account the contribution of the reflected and completed component of the energy flow energy into the total energy of the radiation of surface vibrations. The mechanisms of interaction between the flow of charged particles with the own electromagnetic fluctuations of two -dimensional electronic gas, the occurrence of which is due to the presence of a potential barrier on the border of the media section. Conclusion. Determination of the amplification (generation) modes of electro -radio products that distort their volt are ampere characteristics (reversible failures) depending on the parameters of external electromagnetic radiation. An analysis of the routes obtained in the work can be used in the development of radio emergency for working in a millimeter and submilimeter range (amplifiers, generators and frequency converters). Assessment of indicators of the exponential growth of amplitudes of the own fluctuations of semiconductor components (increement of instability as a criterion of reversible failures) show that the magnitude of the energy of radiation lies within the sensitivity of modern receivers of the radiation of the submilimeter range and is the reason for the failure.

A study protocol for investigating the effects of mobile phone-originated electromagnetic waves on thyroid gland and thyroid hormone activities in the brain

With widespread users across the globe, topic on the impact of mobile phone in particular regarding its electromagnetic wave radiation deserves a priority. Carcinogenic effects of the electromagnetic wave radiation have been suggested by multiple studies. Effects of the radiation are to involve thermal and non-thermal pathways. Among human organs, thyroid gland is susceptible to the radiation exposure due to its location being superficial and close to the radiation transmitter. Previous studies have indicated the correlation between the mobile phone radiation and thyroid dysfunctions. However, a conclusion that the electromagnetic wave radiation is the causative agent of the thyroid dysfunctions has not been reached. Most of the study are unable to remove the influence of the external electromagnetic wave radiation. Hence, this study aimed to perform an investigation with true experimental design using animal model in an anechoic chamber – an isolated chamber which could minimize the electromagnetic wave noise from the outside. In this article, we present the description of the anechoic chamber along with the research protocols. Parameters affecting the investigation, including signal frequencies inside the chamber and specific absorption rate are also measured.

Research on the Induced Electrostatic Discharge of Solar Arrays under the Action of ESD EMP

In this paper, the electrostatic discharge of solar arrays in spacecraft energy systems is taken as the research object. The influence and internal mechanism of external electromagnetic radiation on electrostatic discharge is studied. Meanwhile, the charging and discharging test platform of spacecraft solar arrays under a strong field is first established. Then, the influence of irradiation field strength, electron beam energy and beam density on electrostatic discharge of solar arrays is analyzed and summarized. The results show that during the irradiation process of solar arrays using a high-energy electron beam under vacuum conditions, the higher the electron beam energy and the beam current density, the higher the discharge frequency of the solar array. When the intensity of the external electromagnetic radiation field increases, the discharge frequency also increases. Under the action of external radiation field with the same peak field strength, the larger the gap, the smaller the discharge frequency. With the increase in the field strength, the potential difference of each part of the solar array becomes smaller, and the peak of the discharge current decreases. The research results can provide technical reference for electrostatic protection of spacecraft solar arrays.

Creation of synaptic connection to memristive neurons under noise

Continuous pumping of intracellular and extracellular ions can induce distinct electromagnetic induction accompanied by the channel current. The external electric stimuli and electromagnetic radiation can change the inner field energy in biological neurons, and the firing mode is regulated to discern the energy information in the neurons. The involvement of memristive channel can estimate the effect of electromagnetic field of an isolated neuron, which is sensitive to discern and capture external field energy under electromagnetic field. When two or more neurons with energy diversity are clustered, the synaptic connection is awaken and created with increasing coupling intensity until reaching complete synchronization. In this paper, the memristive Hodgkin–Huxley neuron model is used to discuss the synchronization stability when two neurons with energy diversity are clustered, two identical neurons can be coupled adaptive for reaching complete synchronization and perfect energy balance. In case of electromagnetic radiation, synchronization stability is controlled with increasing the coupling intensity adaptively by imposing noisy disturbance on the magnetic flux variable, which is used to describe the effect of magnetic field. For non-identical neurons, the creation and enhancement of synaptic connection are also realized because of energy diversity between two neurons.

Effect of the Thickness of Nanoscale Layers of the Metal-Dielectric Structure on Its Optical Characteristics

A biosensor is a device which uses a mixture of biological and physicochemical components to detect molecular-level interactions. Essentially, biosensors detect the change in physical properties which occur when an immobilized biological molecule, such as an antibody or a protein, binds to their target analyte. A number of methods have been developed to determine interactions between bioreceptors and their analytes, many of which are based on the principle of Surface Plasmon Resonance, or SPR. The ubiquity of SPR comes from its inherent advantages; it allows real time, highly sensitive monitoring of a wide range of molecular interactions, without the requirement for additional labelling of samples. Surface Plasmon Resonance is caused by the interaction of electromagnetic radiation and the free-flowing cloud of electrons within a metal, a process which induces electromagnetic waves and, under certain conditions, resonance effects. Alterations in the physical conditions at the surface have a significant effect on this resonance, and the detection of these changes form the basis of the SPR biosensor. In the work, the effect of the thickness of the layers of the metal-dielectric structure on its optical characteristics was studied. The simulation was carried out for the Krechman configuration, which is a glass prism on which a multilayer metal-dielectric structure is applied. AuSiO2 was used as a metal-dielectric structure, and a laser beam with a wavelength of 633 nm was used as a source of external electromagnetic radiation. The thickness of the gold film varied from 1 to 60 nanometers. The lowest value of the reflection coefficient is reached at a thickness of 50 nm. The thickness of the silicon dioxide film varied from 1 to 30 nm. When the thickness of the dielectric layer is up to 10 nm, its influence on the optical characteristics is insignificant. Macroscopic values of parameters were used in the study, but it is known that real parameters differ greatly from macroscopic ones. To increase the accuracy of modeling the sensor element in further studies, it will be necessary to take into account dimensional changes in the optical parameters of the nanosized metal component in the structure of the sensor element.

Locking of magnetization and Josephson oscillations at ferromagnetic resonance in a φ0 junction under external radiation

We demonstrate the locking by external electromagnetic radiation of magnetic precession in the $ \varphi_0 $ Josephson junction through Josephson oscillations in the region of ferromagnetic resonance. This leads to a step in the dependence of the magnetization on the bias current, the position of which is determined by the radiation frequency and the shape of the resonance curve. In junctions with a strong spin-orbit coupling, states with negative differential resistance appear on the IV-characteristic, resulting in an additional locking step. A detailed study of the time dependence of voltage and magnetization and their Fourier transforms shows that the corresponding oscillations have the same frequency as the oscillations at the first step, but they have a different amplitude and different dependence on the radiation frequency. This makes it possible to control not only the frequency, but also the amplitude of the magnetic precession in the locking region. It opens up unique perspectives for the control and manipulation of magnetic moment in hybrid systems such as anomalous Josephson junctions.

Nanophoton Generator of Picosecond Pulses

Results of theoretical analyses of possibility of generations of periodic picosecond pulses of voltage are presented. This process is possible under condition of external electromagnetic radiation only. As an active element of such generator may be heterojunction in which the relaxation instability of electron concentration is developed. The possible variant of heterostructure and its static and time depended electric characteristics are demonstrated. Parameters of heterostructure and operating regimes can be select so that pulses of voltage will be in terahertz range.

Multistable dynamics in a Hopfield neural network under electromagnetic radiation and dual bias currents

This paper investigates a Hopfield neural network under the simulation of external electromagnetic radiation and dual bias currents, in which the fluctuation of magnetic flux across the neuron membrane is used to emulate the influence of electromagnetic radiation. Utilizing conventional analytical methods, the basic properties of the proposed Hopfield neural network are discussed. Due to the addition of electromagnetic radiation and dual bias currents, the Hopfield neural network shows high sensitivity to system parameters and initial conditions. The proposed Hopfield neural network possesses multistability with periodic attractor, quasi-periodic attractor, chaotic attractor and transient chaotic attractor, and all of the attractors are hidden attractors because there is no equilibrium point in the system. In particular, when the neuron membrane magnetic flux is different, the system can present transient chaos with different chaotic times. More interestingly, with the change of system parameters, the proposed Hopfield neural network can exhibit parallel bifurcation behaviors. Finally, the Multisim simulation and hardware experiment results based on discrete electronic components are conducted to support the numerical ones. These results could give useful information to the study of nonlinear dynamic characteristics of the Hopfield neural network.