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We experimentally investigate phase shift gained by electromagnetic radiation transmitted through a two-dimensional electron system (2DES) on a dielectric substrate. We systematically examined the dependence of the phase shift on the radiation frequency and 2DES electron density for the GaAs semiconductor substrate. A theoretical approach was developed that found good agreement with experimental results. We demonstrate a practically achievable phase shift of 105 °. Obtained findings pave the way for the design of terahertz devices that can manipulate the radiation phase in a controlled and precise manner. [ABSTRACT FROM AUTHOR]

Transparent and flexible metamaterial absorbers can provide solutions for electromagnetic compatibility and electromagnetic radiation pollution. They also play key roles in platforms with optical windows that require low detectability and immunity to electromagnetic interference. Due to the lack of active adaptability to complex electromagnetic environments, early metamaterial absorbers need to be redesigned and manufactured once the application scenarios change. The new two-dimensional material graphene provides a practical technical approach for the realization of transparent tunable absorbers. In this work, we propose a polarization-insensitive dual-tunable microwave absorber based on graphene metasurface. By controlling two separate bias voltages applied to patterned graphene or continuous graphene, independent dynamic regulation of electromagnetic wave absorption frequency and amplitude is achieved. It also possesses the features of optical transparency and flexibility. The measurement results show that the absorption frequency can be shifted from 9.8 to 11.3 GHz, the peak absorption rate at each absorption frequency remains above 99.6%, and the reflection amplitude modulation can be achieved simultaneously at each absorption frequency. The proposed absorber integrates multiple modulation functions for electromagnetic waves, and the overall structure is optically transparent and flexible. Therefore, it can contribute to many practical wave absorbing applications. [ABSTRACT FROM AUTHOR]

Purcell filters, which serve to suppress electromagnetic radiation and enhance the readout efficiency of qubit, are an indispensable component in superconducting quantum chips. With the increasing scale of quantum chips, the requirements for the performance and scalability of Purcell filters are becoming more stringent. In this report, a novel four-stage Purcell filter that enables fast measurement without exacerbating environmental damping of the qubits is presented. The design approach of the filter is derived from the serial and parallel configurations of λ/4 resonant cavities. The filter exhibits exceptional passband-to-stopband isolation, reaching up to 40 dB of isolation within the transition range of 400 MHz. Furthermore, the filter boasts a wide bandwidth for both the stopband and the passband, with the stopband ranging from 4 to 5.5 GHz and the passband extending from 5.8 to 6.5 GHz. In terms of spatial arrangement, each filter can be connected to over ten readout resonators for qubit readout. This innovative Purcell filter will significantly contribute to the development of high quality, scalable superconducting quantum chips. [ABSTRACT FROM AUTHOR]

Ultrafast optically excited ferromagnetic (FM)/nonmagnetic (NM) multilayer heterostructures have been demonstrated recently as efficient, high-power, and broadband sources of terahertz (THz) electromagnetic radiation. Since these spintronic THz emitters exploit the conversion from ultrafast spin to charge current, either in bulk or at the interface, the THz pulses inhere all the characteristics of the involved mechanisms and dynamics associated with spin-charge interconversion processes. Deconvolving the same requires meticulous and careful experimentation and analysis. In this article, we review the current state-of-the-art in this field and provide a perspective on the emerging phenomena, which are prospering as new research avenues and demonstrate application potential for futuristic THz technologies. In the process of developing efficient spintronic THz emitters by optimizing various conditions including those with material parameters and excitation light, it turns out that THz emission spectroscopy itself can be a unique experimental tool for probing microscopic dynamical magnetic and spintronic effects, induced by femtosecond laser pulse excitation, in a noncontact and noninvasive manner. Several breakthroughs can be listed from the literature in this regard from the last decade. Just recently, ultrafast orbitronics is another dimension that is taking shape and will impact the field immensely. A fair account to this topic is also presented in the article. [ABSTRACT FROM AUTHOR]

We investigate the temporal correlation between very-high-frequency (VHF, at frequencies of the order of 10–100 MHz), ultrahigh-frequency (UHF, at frequencies within 1–6 GHz), and x-ray (with photon energies more than 10 keV) emissions, which accompany the development of a high-voltage discharge initiated in a long gap at voltages up to 1 MV. The x-ray and UHF emissions are found to emerge starting approximately from the prepulse current onset observed before the discharge gap breakdown and both gradually decay coming to this instant. The UHF emission spectrum is represented with frequencies up to 6 GHz, with the highest spectral power being achieved within 1–2 GHz. The radio emission power drops sharply at frequencies below 1 GHz and increases closer to 150 MHz with the highest spectral power of VHF radiation being reached within 60–90 MHz. The VHF emission can appear before the discharge current and UHF emission onsets in the form of 100-ns-long prepulses, and its intensity significantly increases as the UHF emission starts. The analysis of the temporal correlation between x rays, VHF, and UHF radiations, discharge current, and voltage waveforms indicates that the generation mechanisms of the discharge electromagnetic radiations are difficult to be interpreted in terms of the developing or colliding streamer concepts. [ABSTRACT FROM AUTHOR]

This study investigates an axial extension mode magnetoelectric antenna designed for near-field communication in dielectric cluttered environments. The antenna configuration consists of two magnetostrictive Metglas-polymer composites bonded on opposite sides of a PZT-5A actuator, creating a dumbbell configuration. Operating at its 88 kHz mechanical resonance, the antenna emits electromagnetic radiation in the near field by applying an AC voltage to the piezoelectric material, generating an acoustic wave that propagates through the volume and induces oscillating magnetizations. The design uses a system of uncoupled models: an electrostatic finite element model to predict strain that feeds into a Landau–Lifshitz–Gilbert micromagnetic model to predict magnetic moment changes and, subsequently, a dipole model to forecast near-field radiation characteristics. Measurements were conducted on the antenna's impedance, quality factor, mechanical resonance, transmitted magnetic signal strength, and radiation patterns, with variations in the bias magnetic field, frequency, and applied voltage. The results exhibit a strong correlation with model predictions, and the radiated signal strengths compare favorably with those of state-of-the-art pacemaker communication devices. Computational parametric studies using Galfenol and Terfenol-D suggest the potential for up to a three order of magnitude reduction in the antenna's volume, which is critical for implanted medical devices. [ABSTRACT FROM AUTHOR]

To solve the problem of testing the sensitivity under electromagnetic pulse radiation for a hot bridge wire electro-explosive device (EED), this paper simulated and analyzed the correlation between the critical ignition current under steady and pulse excitation. The simulation results showed that, under single pulse excitation, the critical ignition current of the EED decreases with the increase in the pulse width, and the variation law can be divided into three pieces: adiabatic, transition, and constant; while under pulse train excitation, due to the thermal cumulative effect, the critical ignition current is related to both material properties and excitation parameters. By analyzing the simulation results and considering the thermal ignition theory, the mathematical model of the critical ignition current under pulse excitation was established, and the mathematical model showed that under pulse train excitation, the critical ignition current is relevant not only to the single pulse excitation critical ignition current, pulse period, and duty cycle, but also to the ratio of single pulse and steady excitation critical ignition current and the thermal time constant. It was verified that the errors between the theoretical values obtained from the mathematical model and the results obtained from the simulation were within 2.5%. [ABSTRACT FROM AUTHOR]

The plasma-elastic component of the photoacoustic response in the time-domain of thin semiconductor samples excited by long electromagnetic radiation pulses is analyzed in detail. The plasma-elastic component model assumes that ambipolar diffusion can be approximated by the minority carrier diffusion. The results obtained show that the plasma-elastic component in thin semiconductor samples affects photoacoustic measurements in the time domain, which is important for the photoacoustic determination of semiconductor electronic properties. [ABSTRACT FROM AUTHOR]

The physical characteristics of electromagnetic waves are combined with digital information in coding metasurfaces. Coding metasurfaces enable precise control of beams by flexibly designing coding sequences. However, achieving continuous multivariate modulation of electromagnetic waves on passive flexible coded metasurfaces remains a challenge. Previous passive coding metasurfaces have a fixed phase difference between adjacent coding units throughout the operating frequency band, and when the coding pattern is defined, the coded metasurface can only achieve a single electromagnetic function. Our proposed frequency coding metasurface units vary linearly in phase difference over the operating frequency band with different phase sensitivities. Frequency coding metarsurfaces enable a wide range of tunable and versatile electromagnetic energy radiation, without introducing any active devices and changing the coding pattern. As a demonstration of the concept, we have shown theoretically and numerically that frequency coding metasurface can achieve successive transformations of electromagnetic functions, including multi-beam generation, anomalous deflection and diffuse scattering. In addition, beam sweeping function is achieved by means of spatially non-periodically distributed frequency coding metasurface. When the frequency of the incident wave is changed, the deflection angle of the beam is also changed. In addition to the tunability of properties, research on coding metasurfaces has tended to be limited to rigid materials. Flexible coding metasurfaces have potential applications in microwave antennas, radar and aircraft. The passive flexible frequency coding metasurfaces provide a novel approach to manipulating electromagnetic waves with increased design flexibility. This promises applications in microwave antennas, radar, aircraft, and satellite communications. [ABSTRACT FROM AUTHOR]

Introduction: The emergence of electromagnetic wave pollution as a new form of pollution in human society is attributed to the advancements in communication technology and the electronic information business. In addition to harming priceless electronic equipment, these electromagnetic radiation and interference issues brought on by electrical and electronic devices have a major negative influence on human productivity and wellbeing. The secret to getting rid of electromagnetic radiation interference (EMI) and improving performance is electromagnetic shielding technology. Metamaterial absorber is a type of metamaterial that absorb EMI radiation. The benefits of metamaterial absorbers include their lightweight, simple construction, and excellent absorptivity. Methods: This paper proposes a novel metamaterial absorber for EMI radiation absorption. It consists of dielectric layers, metamaterial shielding layer and transmission line. The reflection of radiation is reduced by miniaturization of metamaterials. Results and Discussion: Simulation results show that the proposed design has better performance as compared to existing methods. The operating frequency range is from 23.1 to 28.3 GHz. The values of S21 with and without shielding are -5 dB and -0.05 dB, and the shielding effectiveness is 10.10 dB and a maximum of 12.63 dB. [ABSTRACT FROM AUTHOR]

Polarization relaxation loss caused by defects and interfaces has become a fascinating electromagnetic wave (EMW) loss mechanism. However, the logical relationship between impedance matching and various loss mechanisms requires further elucidation to facilitate more comprehensive and in‐depth research. Herein, phase engineering on molybdenum disulfide (MoS2) is proposed as the main controller of permittivity, offering a straightforward and highly effective method for regulating permittivity. Through the main control of phase engineering, a small gradient, monotonic change of the permittivity across a substantial area is achieved, leading to the gradual transition of the material system from strong loss but impedance mismatching to weak loss but EMW transparent phase. Thanks to the fundamental regulation of impedance characteristic and attenuation capacity by the dielectric gene engineering controlled by the phase engineering, combined with the ingenious coordination of sulfur vacancy‐induced polarization and interfacial polarization, t‐60 harvests an effective absorption band of 6.8 GHz and a minimum reflection loss of −59.8 dB. This study effectively expands the dielectric gene pool and improves the research logic for various loss mechanisms, offering valuable insights for the development of advanced EMW absorbing materials. [ABSTRACT FROM AUTHOR]

Time‐varying electromagnetic materials are introducing new ways to control and transform light waves, unlocking unexplored scattering phenomena. In this paper, the wave phenomena associated with abrupt changes in the surface impedance of a metasurface introduced uniformly in space, forming a time interface are investigated. Efficient transformation of a monochromatic surface wave propagating along the metasurface into a radiated wave at a significantly higher frequency is demonstrated. This phenomenon realizes an efficient radiator for electromagnetic wireless signals at high frequencies relying on generators and modulators operated at a much lower frequency. [ABSTRACT FROM AUTHOR]

The research of the influences of man-made electromagnetic fields on tick physiology has been very sparse and long neglected since the pioneer studies published in 1996 and 2000. Once multiple behavioral tests confirmed an attraction and possible perception of electromagnetic fields in ticks, a new interest in this topic erupted in recent years. In this study, qRT-PCR is utilized to determine the changes in the mRNA transcript levels of neuropeptides SIFamide and myoinhibitory peptide (mip and sifa) and their representative receptors (mip-r1 and sifa-r1) in the synganglia of the tick Ixodes ricinus irradiated by 900 MHz radiofrequency electromagnetic field. It was determined that 40 V/m intensity has a significant suppressory effect on the transcript levels of all genes after at least 60 minutes of constant exposure in both sexes. Commonly occurring intensity of radiation in urban areas (2 V/m) produced an elevation in mRNA levels after various timespans in every gene. A significant decrease of transcript abundances was detected in females after one hour of exposure to 2 V/m. Results of this study widen the knowledge of EMF-induced alterations in the neurophysiology of I. ricinus, the most commonly distributed hard tick in Europe. [ABSTRACT FROM AUTHOR]

Real-time and accurate temperature monitoring during microwave hyperthermia (MH) remains a critical challenge for ensuring treatment efficacy and patient safety. This study presents a novel approach to simulate real MH and precisely determine the temperature of the target region within biological tissues using a temporal-informed neural network. We conducted MH experiments on 30 sets of phantoms and 10 sets of ex vivo pork tissues. We proposed a novel perspective: the evolving tissue responses to continuous electromagnetic radiation stimulation are a joint evolution in temporal and spatial dimensions. Our model leverages TimesNet to extract periodic features and Cloblock to capture global information relevance in two-dimensional periodic vectors from ultrasound images. By assimilating more ultrasound temporal data, our model improves temperature-estimation accuracy. In the temperature range 25–65 °C, our neural network achieved temperature-estimation root mean squared errors of approximately 0.886 °C and 0.419 °C for fresh ex vivo pork tissue and phantoms, respectively. The proposed temporal-informed neural network has a modest parameter count, rendering it suitable for deployment on ultrasound mobile devices. Furthermore, it achieves temperature accuracy close to that prescribed by clinical standards, making it effective for non-destructive temperature monitoring during MH of biological tissues. [ABSTRACT FROM AUTHOR]

Viscose-based carbon fibers (VBCFs) were chlorinated with CCl4 vapor to investigate the effect of chlorination temperature on their microwave properties. The maximum chlorine content of 2.0 mmol g−1 was obtained at 450 °C. TEM and SEM showed carbon nanostructures and surface morphology preservation, respectively. TGA and TPD MS confirmed the formation of carbon-oxygen and chlorine-carbon groups, including CCl3 groups. The prepared chlorinated VBCFs can effectively reflect X-band microwaves, with nearly constant reflection losses over a wide frequency range, and are characterized by minimum transmission losses of −22 dB. [ABSTRACT FROM AUTHOR]

Under compressive loading, rocks emit electromagnetic waves, and monitoring electromagnetic signals has become a key means of predicting dynamic rock disasters. To understand how dynamic potential is generated in rocks under compressive loading, the relationship between the compressive loading (P) and the stimulated potential (E) is seen as a circuit system (H(t)). A circuit analysis model has been established to study how rock particles restructure under compressive loading. Experimental tests were conducted to measure the input excitation (E) and output response (Uσ(t)) or (Iσ(t)) of the rock specimens, with four types of rocks being tested. The experiments revealed that voltage, current, frequency, and impedance changed during the particle reorganization process under compressive loading, showing that the electromagnetic radiation of the rock specimens mainly came from the current generated by the internal particle reorganization. The intensity of electromagnetic radiation was found to depend on the load size and dynamic impedance (Zσ), with the dynamic impedance (Zσ) consisting of the microelement total resistance (Rσ), capacitance (Cσ), and inductance (Lσ). The variation of dynamic impedance (Zσ) is related to the rock type. The research findings have contributed to elucidating the mechanism of electromagnetic radiation generated by rocks under load. [ABSTRACT FROM AUTHOR]

The paper published by Nath et al. (Urban Ecosystems 25:1279–1295, 2022) analyzes the influence of different ecological factors and covariates on House Sparrow (Passer domesticus) abundance but criticizes previous research without explaining in depth the scientific reasons for it and reaches conclusions not supported by the authors' own data nor by existing knowledge and scientific evidence. They state that studies on the impacts of electromagnetic radiation (EMR) on birds outside laboratory conditions carried out in the past did not consider other ecological factors that could also influence the life history needs of the species. However, precisely the opposite is true; the studies carried out so far, taking into account most of the possible factors to consider, including urbanization, have not been able to solve the enigma of the House Sparrow decline in many of the world's cities. Thus, it is necessary to propose new possible causes not considered so far. Among the few that remain to be tested is the electromagnetic radiation hypothesis, which was proposed by two independent research teams in two different countries. This paper is a reply of the work developed by Nath et al. (Urban Ecosystems 25:1279–1295, 2022) that highlight their inconclusive results and methodological flaws due to the correlation observed between radiofrequency electromagnetic fields (RF-EMF) and urbanization, complement their results showing negative correlations when testing House Sparrow abundance with electromagnetic radiation levels correcting for the percentage of builtup, and clarify some statements and misconceptions (importance of non-thermal effects). [ABSTRACT FROM AUTHOR]

For a selection of 35 pulsars with large spin-up glitches (⁠|$\Delta {\nu }/\nu \ge 10^{-6}$|⁠), which are monitored by the Jodrell Bank Observatory, we analyse 157 glitches and their recoveries. All parameters are measured consistently and we choose the best model to describe the post-glitch recovery based on Bayesian evidence. We present updated glitch epochs, sizes, changes of spin down rate, exponentially recovering components (amplitude and corresponding time-scale) when present, as well as pulsars' second frequency derivatives and their glitch-associated changes if detected. We discuss the different observed styles of post-glitch recovery as well as some particularly interesting sources. Several correlations are revealed between glitch parameters and pulsar spin parameters, including a very strong correlation between a pulsar's interglitch |$|\ddot{\nu }|$| and |$\dot{\nu }$|⁠ , as well as between the glitch-induced spin-down rate change |$\Delta \dot{\nu }_{\rm p}$| that does not relax exponentially and |$\dot{\nu }$|⁠. We find that the ratio |$\left|\Delta \dot{\nu }_{\mathrm{p}}/\ddot{\nu }\right|$| can be used as an estimate of glitch recurrence times, especially for those pulsars for which there are indications of a characteristic glitch size and interglitch waiting time. We calculate the interglitch braking index n and find that pulsars with large glitches typically have n greater than 3, suggesting that internal torques dominate the rotational evolution between glitches. The external torque, for example, from electromagnetic dipole radiation, could dominate the observed |$\ddot{\nu }$| for the youngest pulsars (⁠|$\lesssim 10^{4}\,\,\mathrm{yr}$|⁠), which may be expected to display |$n\sim 3$|⁠. [ABSTRACT FROM AUTHOR]

The present study aims to understand key factors influencing the House Sparrow population across different habitat scales in Bhavnagar, Gujarat, India. Correspondingly, different variables such as changes in habitat composition, sound levels, and density of mobile phone base stations were considered with reference to the occurrence of the House Sparrows across the study area. During the study period (December 2016 to November 2018), the number of House Sparrows was recorded through point count without distance estimate method. Non-parametric tests were employed to assess variations in different variables and their correlation with the presence of House Sparrows, revealing that changes in local habitat composition significantly influence their occurrence. Shrubby vegetation, cowsheds, and old/traditional structures emerged as crucial predictors positively impacting House Sparrow's presence, particularly in urban areas where suitable habitat patches are scarce due to urbanization and modern lifestyles. The decline in these habitats has significantly impacted House Sparrow populations. To counter this decline, implementing strategies like providing artificial nest sites is being considered. However, it's crucial to ensure that there are adequate shelter and food resources available to effectively conserve the species. [ABSTRACT FROM AUTHOR]

Exposure to 2.45 GHz electromagnetic radiation (EMR) emitted from commonly used devices has been reported to induce oxidative stress in several experimental models. Our study aims to evaluate the efficacy of sulforaphane, a well-known natural product, in preventing radiation-induced toxic effects caused by a 24 h exposure of SH-SY5Y neuronal-like cells and peripheral blood mononuclear cells (PBMCs) to 2.45 GHz EMR. Cells were exposed to radiation for 24 h in the presence or absence of sulforaphane at different concentrations (5–10–25 µg/mL). Cell viability, mitochondrial activity alterations, the transcription and protein levels of redox markers, and apoptosis-related genes were investigated. Our data showed a reduction in cell viability of both neuronal-like cells and PBMCs caused by EMR exposure and a protective effect of 5 µg/mL sulforaphane. The lowest sulforaphane concentration decreased ROS production and increased the Mitochondrial Transmembrane Potential (Δψm) and the NAD+/NADH ratio, which were altered by radiation exposure. Sulforaphane at higher concentrations displayed harmful effects. The hormetic behavior of sulforaphane was also evident after evaluating the expression of genes coding for Nrf2, SOD2, and changes in apoptosis markers. Our study underlined the vulnerability of neuronal-like cells to mitochondrial dysfunction and oxidative stress and the possibility of mitigating these effects by supplementation with sulforaphane. To our knowledge, there are no previous studies about the effects of SFN on these cells when exposed to 2.45 GHz electromagnetic radiation. [ABSTRACT FROM AUTHOR]

The nutrients present in food are not only prone to a series of physicochemical reactions but also provide conditions for the growth and reproduction of foodborne microorganisms. In recent years, many innovative methods from different fields have been introduced into food preservation, which extends the shelf life while maximizing the preservation of the original ingredients and properties of food. In this field, there is a lack of a systematic summary of new technologies emerging. In view of this, we overview the innovative methods applied to the field of food preservation in recent 3 years, focusing on a variety of technological approaches such as antimicrobial photodynamic therapy based on nanotechnology, electromagnetic radiation sterilization based on radiation technology, and antimicrobial peptides based on biomolecules. We also discuss the preservation mechanism and the application of the different methods to specific categories of products. We evaluated their advantages and limitations in the food industry, describing their development prospects. In addition, as microorganisms are the main causes of food spoilage, our review also has reference significance for clinical antibacterial treatment. [ABSTRACT FROM AUTHOR]

(TiO2) is both a natural and artificial compound that is transparent under visible and near-infrared light. However, it could be prepared with other metals, substituting for Ti, thus changing its properties. In this article, we present density functional theory calculations for Ti(1−x)AxO2, where A stands for any of the eight following neutral substitutional impurities, Fe, Ni, Co, Pd, Pt, Cu, Ag and Au, based on the rutile structure of pristine TiO2. We use a fully unconstrained version of the density functional method with generalized gradient approximation plus the U exchange and correlation, as implemented in the Quantum Espresso free distribution. Within the limitations of a finite-size cell approximation, we report the band structure, energy gaps and absorption spectrum for all these cases. Rather than stressing precise values, we report on two general features: the location of the impurity levels and the general trends of the optical properties in the eight different systems. Our results show that all these substitutional atoms lead to the presence of electronic levels within the pristine gap, and that all of them produce absorptions in the visible and near-infrared ranges of electromagnetic radiation. Such results make these systems interesting for the fabrication of solar cells. Considering the variety of results, Ni and Ag are apparently the most promising substitutional impurities with which to achieve better performance in capturing the solar radiation on the planet's surface. [ABSTRACT FROM AUTHOR]

CubeSat and small satellites play a very important role in modern space exploration. Their success and diverse capabilities rely on the development of efficient and compact sub‐systems. This task is not trivial due to multiple challenges posed by their small size and mass, and the solution calls for conceptually new designs for the fabrication and integration of complex miniaturized satellite components. The importance of additive techniques in small satellite manufacturing is steadily increasing as they enable rapid, large‐scale production of sophisticated architectures, such as hollow, webbed parts with a cell‐like structure similar to animal bone, with lower mass and improved functionality. Moreover, these architectures feature higher strength, enhanced heat transfer, and efficient thermal and electromagnetic radiation shielding. When compared to traditional subtractive technologies like cutting and milling, additive manufacturing proves to be more versatile and effective in realizing architectures with an increasing intricacy of shapes, structures, and compositions. The perspective explores the suitability of 3D printing in various satellite production tasks, including the propulsion system components and satellite elements. Looking ahead, the challenges and advantages of integrating 3D printing technology into satellite production, emphasizing the need for continuous development through consolidated, proactive collaborative efforts of many devoted teams are outlined. [ABSTRACT FROM AUTHOR]

Due to its high biological efficiency, extremely high-frequency electromagnetic radiation is used in medical practice to treat a wide range of diseases, including the cardiovascular system. The purpose of this work was to study the indicators of heart rate variability during the recovery period after a bicycle ergometric test under the conditions of preventive exposure to low-intensity electromagnetic radiation of extremely high frequency. The study involved 120 young girls in the intermenstrual period. The girls in the experimental group were exposed to 30 minutes of low-intensity electromagnetic radiation of extremely high frequency for 10 days. Then all the subjects took part in bicycle ergometric training. In the experimental group, a decrease in the stress index by 36%, and an increase in the power of the spectrum by 64% was noted, which indicates the activation of the parasympathetic division of the vegetative-vascular nervous system and normalization of vegetative effects on the heart. In the experimental group, compared with the control group, there was a less pronounced change in the considered parameters of cardiac activity. [ABSTRACT FROM AUTHOR]

The magnetoelectric (ME) coupling effect is a more effective approach for reducing antenna size. Nevertheless, at low frequencies, a single ME structure generates a weak signal strength and a low signal-to-noise ratio (SNR). This study utilized an array strategy to improve the radiation and induced electromagnetic field performance of ME antennas. In this study, the array ME coupling structure, composed of Metglas and Pb (Zr1−xTix) O3 (PZT) bilayers, was operated through ME coupling resonance modes. The relationship between the sensitivity and SNR of the serially connected ME antenna array and the number of series connections was determined. On the transmission side, the impact of the multi-source power supply modes on the radiation intensity and directivity of the ME antennas was analyzed. The sensitivity, SNR, magnetic detection limit, directivity, and radiation range of the single ME and array ME antennas were tested for the key parameters. Finally, it was demonstrated that at a frequency of 31.75 kHz, the array strategy achieved a low-frequency signal transmission distance of up to 48.1 m, which is 1.7 times that of a single ME antenna. This array strategy significantly enhances the radiation intensity and magnetic field SNR of ME antennas in the low-frequency range, demonstrating its application prospects in the field of low-frequency communication. [ABSTRACT FROM AUTHOR]

This paper presents the deep neural network‐based infinitesimal dipole model using either near‐ or far‐field radiation patterns. Based on the radiating characteristic of an infinitesimal dipole, we generated a data set including near and far field radiation patterns corresponding to the phases of infinitesimal dipoles. We used the data set to train and validate the deep neural network (DNN) model. After checking the statistic of the fit function and the average error in expecting the phases of the infinite dipoles, we conclude that the proposed infinitesimal dipole modeling using DNN is sufficient to predict the characteristics of electromagnetic radiation. [ABSTRACT FROM AUTHOR]

Nowadays, the rapid development of information networks and the large-scale popularization of electronic equipment have provided great convenience for human life. However, the induced electromagnetic radiation has caused threatens to human health and the service life of electronic equipment. To overcome the above shortcomings, recently, functionalized materials with electromagnetic interference (EMI) shielding have been widely investigated and reported. As a renewable natural polymer material, cellulose possesses attractive features such as perfect hydrophilicity, chirality, biodegradability, broad chemical modifying capacity, mechanical properties, and low price. The inherent properties of cellulose make it an excellent substrate for preparing EMI shielding materials. So far, numerous cellulose-based electromagnetic shielding materials have been reported, but the classification and description of the design structures are very rare. In this paper, the basic principles and testing methods of electromagnetic shielding were first systematically summarized, and then the structure and properties of cellulose-based electromagnetic shielding materials were reviewed. In addition, the progress of the current application and structural design of cellulose-based electromagnetic shielding materials were also summarized. Finally, the challenges of cellulose-based electromagnetic shielding materials and the future development trend and opportunity was discussed. This review provided a reference for the further development of cellulose-based electromagnetic shielding materials. [ABSTRACT FROM AUTHOR]

It is shown that a thin film nanocomposite (NC) coating the radiator enhances the electromagnetic radiation in a particular band. The parameter enhancement in a rigid radiator is done with a metal strip, which is not suitable for a flexible substrate radiator. The NC, i.e. carbon nanotubes-iron-nickel-cobalt (CNT-FeNiCo) nanocomposite, proposed in the radiator design has good electric, magnetic and mechanical characteristics suitable for a flexible radiator. The NC film coated on a shorter radiating strip improves the upper band radiation of a dual-band radiator. The bandwidth of the upper band in the NC-coated radiator is enhanced by 102.50% with a good improvement in the gain and radiation efficiency. The concentration and distribution of CNTs in the antenna substrate coating changes the dielectric constant of the substrate, which can be tailored for specific antenna requirements. Unique properties of the CNT-FeNiCo NC synthesized for radiator fabrication are considered. A uniform NC coating is applied in accordance with the thickness and concentration to enhance the electrical conductivity and mechanical properties. The proposed radiator produces a 2.30–4.10 GHz (1.80 GHz) bandwidth in the lower band and 4.75–6.35 GHz (1.60 GHz) in the upper band, which covers the ISM, WLAN, WiMAX, WiFi and 5G bands. [ABSTRACT FROM AUTHOR]

Biological effects of radio frequency electromagnetic radiation (RF-EMR) in the range of 900–1800 MHz emerging from the mobile phone were investigated and were found to influence the locomotor pattern when exposure was initiated from 1 hour post fertilization (hpf) in zebrafish embryos (ZE), Danio rerio. Mobile phones and other wireless devices offer tremendous advantages. However, on the flipside they are leading to an increased electromagnetic energy in the environment, an excess of which could be termed as electromagnetic pollution. Herein, we tried to understand the effects of RF-EMR emerging from the mobile phone, on the development and behavior of ZE, exposed to RF-EMR (specific absorption rate of 1.13 W/kg and 1800 MHz frequency) 1 hr daily, for 5 days. To understand if there could be any developmental stage-specific vulnerability to RF-EMR, the exposure was initiated at three different time points: 1hpf, 6hpf and 24hpf of ZE development. Observations revealed no significant changes in the survival rate, morphology, oxidative stress or cortisol levels. However, statistically significant variations were observed in the batch where exposure started at 1hpf, with respect to locomotion patterns (distance travelled: 659.1 ± 173.1 mm Vs 963.5 ± 200.4 mm), which could be correlated to anxiety-like behavior; along with a corresponding increase in yolk consumption (yolk sac area: 0.251 ± 0.019 mm2 Vs 0.225 ± 0.018 mm2). Therefore, we conclude that RF-EMR exposure influences the organism maximally during the earliest stage of development, and we also believe that an increase in the time of exposure (corresponding to the patterns of current usage of mobile phones) might reveal added afflictions. Mobile phones and other wireless devices are on a rampant usage worldwide. They work by radiating low energy radiofrequency electromagnetic radiations. An excessive usage of wireless devices is leading to increased presence of these radiations in our surroundings. Since these radiations are not physically sensed by the organisms, its impact stays elusive. Nevertheless, the interaction of these radiations with biological systems may produce some unwarranted effects. When we exposed the ZE to the mobile phone radiation daily 1hr for 5days, our observations revealed that the youngest of the experimental group showed susceptibility. The effect was evident through haphazard movements and stressed behavior. So, it is important to be aware of the potential effects and take necessary precautions by following safety guidelines, especially when the organism is in its early life stage. [ABSTRACT FROM AUTHOR]

We present here the fabrication at the wafer level and the electrical performance of two types of graphene diodes: ballistic trapezoidal-shaped graphene diodes and lateral tunneling graphene diodes. In the case of the ballistic trapezoidal-shaped graphene diode, we observe a large DC current of 200 µA at a DC bias voltage of ±2 V and a large voltage responsivity of 2000 v/w, while in the case of the lateral tunneling graphene diodes, we obtain a DC current of 1.5 mA at a DC bias voltage of ±2 V, with a voltage responsivity of 3000 v/w. An extended analysis of the defects produced during the fabrication process and their influences on the graphene diode performance is also presented. [ABSTRACT FROM AUTHOR]

Nowadays, due to their characteristics of high efficiency and energy saving, frequency converters are used in coal mine excavation machines and ventilation machines. They can cause serious electromagnetic radiation interference with the surrounding monitoring, sensing and other equipment. Therefore, it is necessary to explore the electromagnetic interference characteristics of mining converters. By choosing a ZJT-75/660SF mine frequency converter as the research object, an antenna model was established, and the method of moments was used to solve the problem. The electromagnetic radiation characteristics of the frequency converter were analyzed, and a field experiment was conducted to verify the effectiveness of the model by comparing the simulation and experimental data. According to the analysis of the electromagnetic intensity distribution characteristics of the near field and far field, the near-field intensity is concentrated in the inner part of the converter, but the far-field intensity has obvious directional characteristics, which are found to provide a reference value for the location of the underground mining converter. Finally, a method is proposed to improve electromagnetic radiation disturbance by changing the structure of the converter's heat dissipation hole, and the feasibility of this method is verified. [ABSTRACT FROM AUTHOR]

Compelling evidence has shown that geomagnetic disturbances in vertical intensity polarization before great earthquakes are promising precursors across diverse rupture conditions. However, the geomagnetic vertical intensity polarization method uses the spectrum of smooth signals, and the anomalous waveforms of seismic electromagnetic radiation, which are basically nonstationary, have not been adequately considered. By combining pulse amplitude analysis and an experimental study of the cumulative frequency of anomalies, we found that the pulse amplitudes before the 2022 Luding M6.8 earthquake show characteristics of multiple synchronous anomalies, with the highest (or higher) values occurring during the analyzed period. Similar synchronous anomalies were observed before the 2021 Yangbi M6.4 earthquake, the 2022 Lushan M6.1 earthquake and the 2022 Malcolm M6.0 earthquake, and these anomalies indicate migration from the periphery toward the epicenters over time. The synchronous changes are in line with the recognition of previous geomagnetic anomalies with characteristics of high values before an earthquake and gradual recovery after the earthquake. Our study suggests that the pulse amplitude is effective for extracting anomalies in geomagnetic vertical intensity polarization, especially in the presence of nonstationary signals when utilizing observations from multiple station arrays. Our findings highlight the importance of incorporating pulse amplitude analysis into earthquake prediction research on geomagnetic disturbances. [ABSTRACT FROM AUTHOR]

The fabrication of composites with magnetite Fe3O4 nanoparticles was investigated in this research as a method of shielding electromagnetic radiation. The effects were studied of various weight percentages of Fe3O4 nanoparticles on the microwave absorption. XRD, SEM, and a scalar network analyzer were used to characterize the sample. The results showed that the Fe3O4 nanoparticles had an average size of 175 nm. The nanocomposite sample with a thickness of 4 mm and a concentration of 1.5 g in 1 cm3 of silicon rubber had the highest level of reflection loss (-23 dB). [ABSTRACT FROM AUTHOR]

Conductive textiles with electromagnetic interference (EMI) shielding functionality are highly desirable for growing flexibility requirements of EMI shielding devices. Most extant shielding coatings on textiles rely on rigid nanomaterials, which are susceptible to detachment, and generate a great deal of reflected EM waves. Thus, there is a high demand for shielding coatings on textiles that are stretchable, stable, and capable of suppressing the secondary reflection toward incident EM waves. Liquid metal is a particularly suitable candidate owing to its high electrical conductivity and excellent conformality. Herein, a straightforward coating strategy is developed for fast fabrication of Ion/Clay‐F that is reinforced with ionogel encapsulation. Especially, the method enables the direct transformation of fluid‐like liquid metal into a clay‐like state and the preparation of ionogel sealings from monomer solutions. The resulting Ion/Clay‐F exhibits promising features, including high total EMI shielding effectiveness (SET) (highest value of 49.3 dB for a single layer and an average value of 73.0 dB for three layers), low reflectivity (0.404), improved tensile strength (13.16 MPa) and tolerance in a wide range of temperatures (−18–100 °C). Remarkably, such Ion/Clay‐F outperforms pure cotton fabric in terms of thermal management, delivering superior heat dissipation and thermal insulation properties. [ABSTRACT FROM AUTHOR]

This study proposes to investigate the effects of microwave radiation and its thermal effects, compared to thermal effects alone, on the bioenergetics of mitochondria isolated from mouse liver. The main parameters investigated in this study are mitochondrial respiration (coupled states: S3 and S4; uncoupled state), using a high-resolution respirometer, and swelling, using a spectrophotometer. Mitochondria irradiated at 2.45 GHz microwave with doses 0.085, 0.113 and 0.141 kJ/g, presented a decrease in S3 and uncoupled state, but an increase in S4. Conversely, mitochondria thermally treated at 40, 44 and 50 °C presented an increasing in S3 and S4, while uncoupled state was unaltered. Mitochondrial swelling increases as a function of the dose or temperature, indicating membrane damages in both cases. Microwave radiation and thermal effect alone indicated different bioenergetics mitochondria response. These results imply that the effects due to microwave in medical treatment are not exclusively due to the increase in temperature, but a combination of electromagnetic and thermal effects. [ABSTRACT FROM AUTHOR]

The impact of electromagnetic radiation from communication on the male reproductive system has emerged as a significant concern in public health. A notable distinction of the 5G sub-6 GHz band, compared to traditional 2G, 3G, and 4G frequency bands, is the inclusion of higher frequency bands. This has raised public concerns regarding the potential effects of these higher frequencies on organisms, particularly their reproductive systems. While it is imperative to investigate the biological effects and potential risks associated with these new frequency bands in laboratory settings, comparing and evaluating differences between various frequency bands remain challenging due to the absence of standardized parameters such as exposure conditions and duration. In contrast, dose assessment offers a simpler and more reliable approach. The dose assessment method was employed in this study to investigate the risks associated with sub-6 GHz electromagnetic radiation from 5G base stations on the male reproductive system. A classical human body model (Duke) was utilized, and an electromagnetic simulation environment was established based on the actual polarization direction of the exposed base stations and various body postures. This research explored the effects of field direction, posture, public population, and frequency on the specific absorption rate of the reproductive system. While maintaining the same level of exposure, a higher frequency results in a reduced dosage on reproductive system. Further analysis reveals that, considering the public exposure threshold, the employment of higher frequency bands in 5G sub-6 GHz does not present a greater dosage on reproductive system compared to lower frequency bands. Consequently, with regard to dosage, there is no need for excessive concern among the general public regarding the impact of electromagnetic radiation emitted by 5G base stations operating below 6 GHz on male reproductive health. [ABSTRACT FROM AUTHOR]

Terahertz (THz) electromagnetic interference (EMI) shielding materials is crucial for ensuring THz electromagnetic protection and information confidentiality technology. Here, it is demonstrated that high electrical conductivity and strong absorption of THz electromagnetic radiation by type‐II Dirac semimetal PdTe2 film make it a promising material for EMI shielding. Compared to MXene film, a commonly used metallic 2D material, the PdTe2 film demonstrates a remarkable 40.36% increase in average EMI shielding efficiency per unit thickness within a broadband THz frequency range. Furthermore, it is demonstrated that a photoinduced long life‐time THz transparency in Dirac semimetal PdTe2 films is attributed to the formation of small polarons due to the strong electron‐phonon coupling. A 15 nm‐thick PdTe2 film exhibits a photoinduced change of EMI SE of 1.1 dB, a value exceeding three times that measured on MXene film with a similar pump fluence. This work provides insights into the fundamental photocarrier properties in type‐II Dirac semimetals that are essential for designing advanced THz optoelectronic devices. [ABSTRACT FROM AUTHOR]

Passive dosimeters enabling accurate measurement of doses from gamma rays to visible light are necessary to ensure efficient utilization of electromagnetic radiation in numerous fields like medical diagnostics and industrial manufacturing. The specific requirements for dosimeters in terms of dosimetry range, sensitivity, accuracy, and stability for each application have led to the development of various dosimeters based on new materials and new mechanisms. Here, a comprehensive review of different types of dosimeters classified according to the response signal, namely electron paramagnetic resonance, electrical, and optical, is provided. This review starts with a general introduction to dosimetry, a classification of dosimeters, and an elucidation of the necessity of dosimeters in various ranges of the electromagnetic spectrum. This is followed by an overview of the fundamental requirements of dosimeters, an explanation of the general dosimetry procedure, and the dosimetric quantities. Emphasis is given to the working mechanism, the design concept, and applications of each type of dosimeter as well as their respective strengths and drawbacks. Challenges and prospects are presented at the end of the review. This review provides an insightful overview of the material‐mechanism‐characteristics‐application relationship of different types of dosimeters that hopefully can serve as inspiration for the development of new devices. [ABSTRACT FROM AUTHOR]

Poly(vinyl chloride) (PVC) and activated carbon (AC) powders were hot-pressed into (PVC)100–x/(AC)x thin-film composites (TFCs), where x = 0.2–30 wt%. The nanostructure, morphology, and composition of AC were investigated by TEM, SEM, and EDX. The thermal stability and surface carbon-oxygen groups of the AC filler were determined by thermolysis in air and vacuum. The AC effect on the (PVC)100–x/(AC)x TFCs transparency to the electromagnetic radiation (EMR) was demonstrated at Ka-band microwave frequencies. Characteristically, the EMR reflection of the TFCs increases with the x value. For reduced EMR reflection, these TFCs should contain only 0.2 wt% AC. [ABSTRACT FROM AUTHOR]

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In this work, electrically conductive thermoplastic elastomeric blend composite films based on polystyrene (PS)/ethylene‐co‐methyl acrylate (EMA) filled with functionalized graphene were developed via the solution mixing technique. Morphological analysis revealed that selective localization of amine‐functionalized reduced graphene oxide (G‐ODA) sheets in the EMA phase of co‐continuous binary blend formed a well‐connected dense conductive pathway by graphene sheets ultimately facilitating the double percolation phenomenon. The electrical percolation threshold was achieved at ~2 wt% of G‐ODA loading which was much lower than that for both single polymer composites. An electrical conductivity of 0.9 S/cm was obtained for blend composite film with 10 wt% of graphene concentration whereas for the same filler loading, PS and EMA composites exhibited electrical conductivity of 1.9 × 10−1 and 2.3 × 10−1 S/cm, respectively. The obtained thermal conductivity of the blend composite with 10 wt% of G‐ODA loading was 0.95 W/m K with 400% enhancement compared to the neat blend system. The same composite exhibited increased real and imaginary permittivity of 92 and 83, respectively. The electrical percolation threshold is well‐correlated with the percolation concentration found from storage modulus and thermal conductivity data. The fabricated PS/EMA blend composite film exhibited absorption‐dominant electromagnetic interference SE of −25 and − 35 dB in X‐band frequency (8.2–12.4 GHz) for 10 wt% of graphene loading with a sample thickness of 0.5 and 1 mm, respectively. [ABSTRACT FROM AUTHOR]

A comprehensive study was performed on the supramolecular ordering and optical properties of thin nanostructured glycerohydrogel sol-gel plates based on chitosan L- and D-aspartate and their individual components in the X-ray, UV, visible, and IR ranges. Our comparative analysis of chiroptical characteristics, optical collimated transmittance, the average cosine of the scattering angle, microrelief and surface asymmetry, and the level of structuring shows a significant influence of the wavelength range of electromagnetic radiation and the enantiomeric form of aspartic acid on the functional characteristics of the sol-gel materials. At the macrolevel of the supramolecular organization, a complex topography of the surface layer and a dense amorphous–crystalline ordering of polymeric substances were revealed, while at the nanolevel, there were two forms of voluminous scattering domains: nanospheres with diameters of 60–120 nm (L-) and 45–55 nm (D-), anisometric particles of lengths within ~100–160 (L-) and ~85–125 nm (D-), and widths within ~10–20 (L-) and ~20–30 nm (D-). The effect of optical clearing on glass coated with a thin layer of chitosan L-(D-)aspartate in the near-UV region was discovered (observed for the first time for chitosan-based materials). The resulting nanocomposite shape-stable glycerohydrogels seem promising for sensorics and photonics. [ABSTRACT FROM AUTHOR]

Electromagnetic shielding parameters are crucial to investigate unexplored nanoparticles and their nanocomposites. Herein, calcium–iron–aluminium (Ca: Fe: Al) nanocomposites are synthesised using the simple solution combustion technique. The as-synthesised nanocomposites with various doping concentrations of Al nanoparticles are characterised to study the structural and surface parameters and to confirm the successful formation. Further, the procured Ca: Fe: Al nanocomposites along with various doping concentrations are utilised for electromagnetic shielding applications, and various shielding parameters are calculated. It was confirmed that Ca: Fe: Al nanocomposites are suitable for electromagnetic shielding applications. [ABSTRACT FROM AUTHOR]

Researching and manufacturing materials that possess both electromagnetic interference (EMI) shielding and infrared stealth capabilities is of great significance. Herein, an ultrathin polyimide-based nonwoven fabric with low-reflection EMI shielding/infrared stealth performance is successfully fabricated by in-situ loading of Fe3O4/Ag nanoparticles on the surface of polyimide (PI) fiber (PFA), and followed by bonding with a commercial Cu/Ni mesh. The synergistic assembly of PFA and Cu/Ni promotes the rational construction of hierarchical impedance matching, inducing electromagnetic waves (EMW) to enter the composite and be dissipated as much as possible. Meanwhile, the existence of Cu/Ni mesh on back of PFA facilitates the formation of electromagnetic resonance and destructive interference of EMW reflected from composite, leading to a lower-reflectivity (0.26) EMI shielding performance of 58 dB within 24–40 GHz at a thinner thickness (430 µm). More importantly, the fluffy PFA nonwoven fabric and metal Cu/Ni mesh endow composite with good thermal insulation and low infrared emissivity, resulting in excellent infrared stealth performance in various environments. As a result, such excellent compatibility makes it possible to become a promising defense material to be applied in military tent for preventing electromagnetic and infrared radiation. [ABSTRACT FROM AUTHOR]

We consider the problem of the magnetization dynamics of a nanosized ferromagnetic sample caused by the spin–orbit interaction of electrons arising in the field of an incident electromagnetic wave. We discuss the case when the frequency of the incident electromagnetic radiation is close to the frequency of the interband transitions. We show that with the use of high-power lasers, this mechanism causes the appearance of a magnetization component perpendicular to the initial magnetization of the sample. This component shows oscillations with a frequency lower than that of incident electromagnetic waves. These dynamics make possible the magnetization reversal of the sample. [ABSTRACT FROM AUTHOR]