Electromagnetic Wave Radiation Research Articles

The influence of load type on electromagnetic wave radiation during the opening of circuit breaker

Radiated electromagnetic waves during the opening of the circuit breaker can be used to evaluate the arc extinguishing performance of the circuit breaker. Current research shows that the duration of electromagnetic waves is the main feature. However, the current research does not consider the influence of the type of load on the electromagnetic wave radiation during the opening process. In this paper, an experimental research platform is established, and the influence of the load type on the electromagnetic wave radiation during the opening process is studied by testing the resistance, inductance and capacitance loads. The research results show that the arcing time and visible arcing times of breaking capacitive loads are significantly greater than resistive and inductive loads.

Gradient 3D-printed honeycomb structure polymer coated with a composite consisting of Fe3O4 multi-granular nanoclusters and multi-walled carbon nanotubes for electromagnetic wave absorption

Electromagnetic wave radiation has adverse health effects on humans and can hamper nearby electronic devices’ regular operations. Therefore, the need to develop new materials with a substantial wave absorption property, a broad absorption bandwidth in a wide incident angle, and lightweight is of enormous technological interest worldwide. Here we report the experimental frequency-dependent permittivity and permeability behaviors of the composite consisting of Fe3O4 multi-granular nanoclusters (MGNCs) and multi-walled carbon nanotubes (MWCNTs). We also apply the results for the starting point for the gradient honeycomb structure design and optimization. We study the effect of the tilted angle on the reflection loss (RL) by finite element analysis (FEM). We obtain a flat RL over the X-band for the regular honeycomb structure with a 0° tilted angle. An increase in the tilted angle from 0° to 4° increases the RL, and a peak is formed at the maximum tilted angle of 4°. Coating the regular honeycomb structure with a thin layer of MGNC/MWCNT enhances the electromagnetic shielding (EMI). Furthermore, as tilted angle increases for the coated honeycomb structure from 0° to 4°, SE increases dramatically over the frequency range from 8.2 to 12.4 GHz at incident wave angles of 0° and 90°.

Solving problems of radiation and diffraction electromagnetic waves based on integral representations electromagnetic field

Annotation Various forms of integral representations of the electromagnetic field are considered. It is shown that the use of analytically developed integral representations of the electromagnetic field instead of the vector potential method makes it possible to significantly simplify the formulation of the internal and external electrodynamic problem for specific structures. The numerical results of solving problems of radiation and diffraction of electromagnetic waves are presented. It is shown that taking into account the peculiarities of the geometry and using projection functions close to the eigenfunctions of the integral operator of the internal electrodynamic problem for basic elements make it possible to construct effective algorithms for the electrodynamic analysis of metastructures. A mathematical model of a multistage chiral frame is proposed. By the example of a tubular vibrator, the possibility of approximating the solution of an internal electrodynamic problem using eigenfunctions is demonstrated. The prospects for further development of the integral representations of the electromagnetic field method are considered.

Cyber Crime, Cyber Space and Effects of Cyber Crime

Cyberspace is a domain that uses the electronic and electromagnetic spectrum to store, modify, and exchange data through network and system-related physical infrastructures. Cyberspace is an endless space known as the Internet. Computer transactions, especially transactions between different computers, can be viewed as a space. Images and text on the Internet exist in cyberspace. The term is used in conjunction with virtual reality, giving the name of the imaginary place where a virtual object exists. If a computer creates a picture of a building that allows the architect to "walk in" and see what the nature of a design is, the building is said to be in cyberspace.Cybercrime is a series of organized criminal attack cyberspace and cyber security. Cybercrime such as Hacking into computer,this can be through a network system and clicking on unfamiliar links connecting to unrecognized Wi-Fi, downloading software and files to unsafe sites, consuming energy, electromagnetic radiation waves, and more. Cyber security is a serious problem and must be taken seriously as it has become a national concern. Currently, most electronic devices such as computers, laptops and cell phones come with built-in firewall security software, but even so, computers are not 100 percent accurate and reliable in protecting our data.

On Describing the Radiation and Diffraction of Electromagnetic Waves by the Eigenfunction Method

On Describing the Radiation and Diffraction of Electromagnetic Waves by the Eigenfunction Method

Low-Power Radar System for Noncontact Human Respiration Sensor

The development of a radar system for human respiration noncontact sensor will contribute to the healthcare field, particularly in the monitoring of patients’ respiration for a long period with all the while providing more advantages, such as hygiene and comfort. The radar system must be able to detect the small displacement with millimeters or centimeters scale on the human body associated with the respiratory activity. The minimum power of electromagnetic wave radiation is also needed to avoid unsafe usability in patients’ respiration monitoring. To attain low power operation and efficient frequency spectrum usage, the multifrequency continuous-wave (MFCW) radar system is proposed in this article as a noncontact sensor for human respiration. The simulation study and laboratory experiment of the MFCW radar system in detecting human respiration were performed, and the comparison study with frequency-modulated continuous-wave (FMCW) radar was discussed in this article. The simulation shows that the effective isotropic radiation power (EIRP) of MFCW is 9 dBm lower than FMCW at a 2-m measurement distance. The result also demonstrates that the proposed MFCW performs well under amplitude and phase noise. The laboratory experiments were conducted by implementing the proposed system using the software-defined radio device. The experiment results also confirm that the proposed MFCW was able to reduce the EIRP and spectrum occupation compared to the FMCW. The MFCW system is then recommended as a radar system in developing a noncontact sensor for respiration monitoring in healthcare.

Электромагнитное излучение при ударном изменении намагниченности под действием фемтосекундного импульса света

The results of investigation of electromagnetic wave radiation by shock changing if magnetization subjected by action of powerful light pulse having femto-second duration are presented. As a mechanism of radiation is presented the model of rapid approaching motion of two different signs magnetic charges. It is found the dependencies of magnetization from the time in connection with duration of pulse. It is found the amplitude-frequency characteristics of radiated waves spectrum. It is found the space-diagram directions of radiation.

The microwave absorption properties of Y2Fe16Si@MOF and Y2Fe16Si@GO composites

With the development in communication technology, severe electromagnetic wave radiation pollution has been created, resulting in electromagnetic interference and health hazards. Thus, materials with excellent microwave absorbing properties have become an urgent need. Magnetic particles with core-shell structures are widely used as microwave absorbers due to their high magnetic loss, little eddy current effect, and tunable dielectric properties. Herein, carbonized Metal-Organic Framework (MOF), and Graphene Oxide (GO) are used to coat the Y2Fe16Si (YFeSi) magnetic powders to form YFeSi@MOF and YFeSi@GO core-shell structures. Their microwave absorption properties are studied. The reflection loss (RL) of YFeSi@MOF can reach -19.2dB@15.1GHz under 1.4 mm thickness with an effective bandwidth of 4.7 GHz, and the reflection loss of YFeSi@GO can reach -18.3dB@16.2GHz under 1.6 mm thickness with an effective bandwidth of 3.9 GHz.

Methods of Protecting Buildings against HPM Radiation—A Review of Materials Absorbing the Energy of Electromagnetic Waves

The pulsed high power microwave (HPM) technology has been developed worldwide for over 20 years. The sources of HPM pulses are a weapon of mass destruction. They pose danger especially to computer and telecommunications equipment and systems, both the military and civilian ones. This paper presents a survey of literature on electromagnetic wave radiation absorbing and shielding materials to be used in construction. Relevant protective measures should include the shielding of buildings or their parts and the absorption of radiation by building envelopes and their elements. The main focus is on the possibilities of improving the shielding and absorptive properties of common construction materials, such as concrete, mortars and synthetic resins. The survey covers the following groups of materials: carbon-based admixtures, nickel powder, iron powders, ferrites, magnetite and polymers. The final part of the survey is devoted to hybrid foam microwave absorbers in which the shape of the material’s inner structure and that of its surface play a special role.

Axial anomaly generation by domain wall motion in Weyl semimetals

A space-time dependent node separation in Weyl semimetals acts as an axial vector field. Coupled with domain wall motion in magnetic Weyl semimetals, this induces axial electric and magnetic fields localized at the domain wall. We show how these fields can activate the axial (chiral) anomaly and provide a direct experimental signature of it. Specifically, a domain wall provides a spatially dependent Weyl node separation and an axial magnetic field $\textbf{B}_5$, and domain wall movement, driven by an external magnetic field, gives the Weyl node separation a time dependence, inducing an axial electric field $\textbf{E}_5$. At magnetic fields beyond the Walker breakdown, $\textbf{E}_5\cdot\textbf{B}_5$ becomes nonzero and activates the axial anomaly that induces a finite axial charge density -- imbalance in the number of left- and right-handed fermions -- moving with the domain wall. This axial density, in turn, produces, via the chiral magnetic effect, an oscillating current flowing along the domain wall plane, resulting in a characteristic radiation of electromagnetic waves emanating from the domain wall. A detection of this radiation would constitute a direct measurement of the axial anomaly induced by axial electromagnetic fields.

From Waste to Wealth: A Lightweight and Flexible Leather Solid Waste/Polyvinyl Alcohol/Silver Paper for Highly Efficient Electromagnetic Interference Shielding.

With the popularization of 5G communications and the internet of things, electromagnetic wave (EW) radiation pollution has aroused much concern from the public, and the search for new materials and technologies for preparing electromagnetic shielding materials still continues all around the world. However, the contradiction among high shielding performance, economic applicability, and flexibility is still not well balanced. Herein, we fabricated a novel foldable leather solid waste (LSW)/polyvinyl alcohol (PVA)/silver (Ag) paper with excellent electromagnetic interference (EMI)-shielding ability using a facile but sustainable electroless plating (ELP) method with LSW as the resource. Taking PVA as a cross-linker, debundled leather fibers (LFs) generated by solid-state shearing milling could generate a flexible LSW/PVA substrate with a high specific surface area, and eventually the deposited Ag layer served as a protective layer not only to significantly improve the mechanical and thermal robustness, but also to endow the LSW/PVA/Ag paper with good hydrophobicity, which could protect from potential moisture damage. In addition to the reflection effect of metallic Ag on EW, the hierarchical structure of collagen fibers played an important role in superior high EMI-shielding effectiveness (∼55-∼90 dB) by an absorption-dominant EMI-shielding mechanism. Furthermore, a multilayer LSW/PVA/Ag paper was also prepared with enhanced EMI-shielding effectiveness of 111.3 dB benefited by constructing multiple reflection-absorption interfaces. The high-performance, environmentally friendly, and low-cost EMI-shielding materials not only offered a new avenue toward recycling LSW in a more value-added way, but also displayed promising potential for application in flexible shielding materials or wearable clothing.

Microwave induced dielectric heating for the on-demand development of indomethacin amorphous solid dispersion tablets

The poor aqueous solubility of drugs challenges their pharmaceutical development and oral bioavailability. At present, the development of dosage forms with poorly water-soluble active pharmaceutical ingredients (APIs) by means of amorphous solid dispersions (ASDs) approach has been an active area of research. Meanwhile, dielectric heating, a process in which a radio frequency (RF), radio wave or microwave electromagnetic radiation heats materials with dielectric properties, has been applied in the food industry and synthetic organic chemistry for many years. In this work, tablets of indomethacin (IND) ASDs with various polymer matrices were successfully obtained utilizing a novel dielectric heating method on-demand. A series of solid-state analyses, including differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), and polarized light microscopy (PLM) were used for examining drug/polymer miscibility, drug crystallinity and to determine the thermal stability of IND/polymer compositions. In addition, the comparative studies between the amorphous tablets and conventional directly compressed (DC) tablets exhibited higher hardness/compaction results for ASDs tablets (for Soluplus®, HPC HF), but smaller values for the other polymers (HPMC, HPMCAS, E PO, and P EO). The amorphous IND tablets showed improved drug release performance because the polymer matrix stabilized the solution that can maintain a thermodynamic environment for IND. An advanced release mechanism and kinetics study revealed that all ASD tablets exhibited mostly a Fickian diffusion. In contrast, non-cellulose polymer matrices showed swelling, erosion, or both swelling and erosion-controlled drug release. In summary, dielectric heating techniques offer a simple way to manufacture amorphous drug products and presents an alternative solution to the patient to optimize their treatment with conventional dosages.

Used dye adsorbent derived N-doped magnetic carbon foam with enhanced electromagnetic wave absorption performance

The increasing excess electromagnetic wave (EMW) radiations induce a serious pollution problem. The social requests urgently for EMW absorbing materials. Herein, as-prepared magnetic carbon foam (MCF) adsorbed RhB from the dye pollutant solutions. The used adsorbent was heat-treated at high temperature. Then, magnetic particle-decorated N-doped carbon foams (N-MCFs) were fabricated. N-doping content is determined by mass ratio of adsorbed RhB vs MCF. Excellent EMW absorption performance is achieved by optimizing impedance matching of N-MCFs. N-MCF-2 with a loading rate of 15% exhibits a lowest RLmin value of −60.46 dB with a Tm value as thin as only 1.70 mm. The corresponding effective bandwidth is 14.29 GHz and 13.79 GHz for −10 dB and −20 dB, covering the whole C band, X band and Ku band. For the absorbers with higher conductivities, the corresponding EMW absorption capacity can be further improved by reducing the loading rate. The distorted skeletons caused by N-doping induce the graphite lattice distortion and local density change of the carbon atomic state, significantly contributing to the magnetic moment. The enhanced dielectric loss by both defect polarization and dipole polarization effects, as well as the activated complex permeability by α-Fe/Fe3C/Fe2O3 composites decoration, are beneficial to EMW absorption.

EVIDENCE OF HUMAN INTER-TISSUE BIOELECTROMAGNETIC TRANSFER: THE HUMAN BLOOD TISSUE INTRINSIC BIOELECTROMAGNETIC ENERGY TRANSFERRING ONTO A MINIORGAN

Basically the human hair consists of a follicle a.k.a root penetrating the skin and an outer skin structure commonly called the shaft. The hair follicle has been classified as a miniorgan having its own cells divisions; aging stages and also demonstrated to emit electromagnetic radiation. The intent of this manuscript is to demonstrate via in vitro experiments evidence of human inter-tissue electromagnetic energy transfer through a glass slide, namely from human blood tissue to the previously described miniorgan or follicle. 
 The mechanism behind this new finding was possible due to the introduction in 2015 of a tabletop optical microscopy method designed to display plants and animal tissue electromagnetic energy emissions. Essential to present finding is the described property of anisotropic crystals of full absorption of incoming electromagnetic radiation waves. K3Fe is an anisotropic crystal. For example, a single layer human blood smear was sandwiched (SDW) by a second glass slide. On the top slide of the SDW, a freshly plucked in toto human hair was then covered by drops diluted K3Fe. Control experiments had repeatedly shown orderly semicircular periodic crystals of K3Fe triggered by the electromagnetic waves emitted by the hair follicle. Prior experiments by this author, have hinted at a “bioelectromagnetic cross-talk” between the follicle and blood. This was seen when there was physical contact between the follicle and blood drops on a glass slide. In the present experiments there is no direct tissue contact, the energy is transmitted through a 1 mm glass barrier. The data herein presented introduces Bioelectromagnetic Fields (BEMFs) energy from human blood onto a miniorgan. This energy is shown penetrating a 1 mm glass slide barrier. Further research is warranted to assess the physiological implications of the human blood tissue as a molecular and BEMFs energy source.

Prediction Model of In-Band Blocking Interference under the Electromagnetic Radiation of Dual-Frequency Continuous Wave

Two hypotheses for the blocking effect mechanisms under the electromagnetic radiation are presented, and the corresponding dual-frequency interference prediction models are proposed, which can be used to predict the working state of equipment under the condition that the single-frequency susceptibility is known. By taking a radar and a communication radio as the EUT, the experiments of dual-frequency continuous wave electromagnetic radiation are designed and carried out to verify the prediction models. The test results show that the sensitive bandwidth of blocking interference effect for the tested radar and the communication station is consistent with their working bandwidth, respectively. By substituting the test data into the proposed prediction models, the prediction errors of the models are less than 13%. Moreover, it can be found that the tested radar is more sensitive to the peak value of electric field, and the tested communication station is more sensitive to the effective value of electric field.

The effect of Joule heating on the terahertz radiation in the superconductor media

Moving vortex lattice in type-II superconductors can result in the radiation of electromagnetic waves in the range of terahertz frequency. The vortex flow dynamics in superconductors follow the London equation. In this paper, the effects of the superconductor coherence length and the London penetration depth on the radiated power is investigated by solving the London equation in the presence of vortices. The results show that by decreasing the coherence length, the radiation power will significantly increase. Also, it is possible to obtain more radiated power with a sharp peak by increasing the penetration depth. Further investigation of the effect of Joule heating reveals that radiation power is almost independent of temperature when we are far from critical temperature. But on the other hand, near the critical temperature, the radiation power is strongly dependent on the temperature variation. Also, by increasing the bias current, the radiation power will augment, and the frequency of radiated peaks will change accordingly.

Precision Measurements of Temperature‐Dependent and Nonequilibrium Thermal Emitters

AbstractThermal emission is the radiation of electromagnetic waves from hot objects. The promise of thermal‐emission engineering for applications in energy harvesting, radiative cooling, and thermal camouflage has recently led to renewed research interest in this topic. However, accurate and precise measurements of thermal emission in a laboratory setting can be challenging in part due to the presence of background emission from the surrounding environment and the measurement instrument itself. This problem is especially acute for thermal emitters that have unconventional temperature dependence, operate at low temperatures, or are out of equilibrium. In this paper, general procedures are described, recommended, and demonstrated for thermal‐emission measurements that can accommodate such unconventional thermal emitters.

Излучение электромагнитной волны из магнитной пленки при воздействии фемтосекундного импульса света

Излучение электромагнитной волны из магнитной пленки при воздействии фемтосекундного импульса света

Predicting plasma properties using power‐controllable fluorescent lamps under electromagnetic wave radiation

This research proposed an experimental method to predict plasma properties in fluorescent lamps with the aid of electromagnetic (EM) wave propagation. A set of power-controllable fluorescent lamps are placed between two antennas as a layered plasma medium. The electron density of plasma was adjusted through luminance control of the fluorescent lamps, and the transmission of the EM wave through the area occupied by plasma was achieved. The EM wave reflection and transmission through the plasma area were experimentally measured. By using the time-domain experimental method, and with aid of the Fourier transformation, EM wave changes in the phase and variance in the intensity are tested. The plasma collision frequency and electron density are then mathematically derived based on the EM wave scattering model theory in unmagnetized plasma. This research provides an experimental approach to predict the plasma properties and diagnose the interaction between EM waves and plasma. The proposed experimental method can be implemented with other types of antennas and extended to a wide range of circumstances, such as monitoring the discharge changes in other plasma sources.

The application of small size spiral tube coil antenna in the development of electromagnetic radiator

When the electromagnetic wave propagates in water, the attenuation will increase with the increase of frequency, so the application of electromagnetic wave in water is limited to the low frequency band. At present, in order to realize the low-frequency electromagnetic wave radiation, the commonly used method is tuning the spiral tube coil antenna (Electromagnetic radiator). In practical application, the electromagnetic radiator used to realize high-power electromagnetic radiation usually has the characteristics of large size and many coil turns. Therefore, for the development of high-power electromagnetic radiator, there are many difficulties, such as high cost and difficult manufacture. Therefore, it is necessary to analyse the relationship between the radiation performances of different sizes of electromagnetic radiator, and use this relationship to guide the development of high-power electromagnetic radiator. Based on this, this paper analysed the radiation characteristics of spiral tube coil antenna, and the application of small-size electromagnetic radiator in the development of electromagnetic radiator.