Field Of Electromagnetic Wave Research Articles

The configuration and detection characteristics of a 3D holographic LWD instrument antenna system based on multi-component EM induction theory

In order to improve the precision of electromagnetic resistivity logging, while ensuring the reliability of boundary detection and anisotropy identification, this study starts from the theory of multi-component electromagnetic induction. Through deriving the formula of component responses, the analytical expressions of electromagnetic wave fields are obtained for various coil pairs of azimuthal instruments. A 3D holographic LWD instrument antenna configuration is constructed, with co-planar and non-coplanar, tilted and orthogonal coil combinations, all components of the magnetic field tensor Hxx,Hxy,Hxz,Hyx,Hyy,Hyz,Hzx,Hzx,HzzHxx,Hxy,Hxz,Hyx,Hyy,Hyz,Hzx,Hzx,Hzz are successfully resolved. With the combination of some or all components, functional signals are generated for specific detection objectives. Numerical simulation of the response of those signals shows that the distance of boundary detection and anisotropy identification capability are superior to traditional geo-signals. The response relationship shows that as the contrast of the formation resistivity decreases and the well deviation angle increases, the anisotropy identification capability gradually strengthens, and the signal strength and identification capability are better at frequency in the range of 400–600 kHz. The proposed antenna configuration has the potential to significantly enhance formation evaluation and to improve geo-steering capability, contributing technology-wise to the optimal landing trajectory and best wellbore position, resulting in cost saving and maximize oil & gas production.

Time‐domain finite element method based on arbitrary quadrilateral meshes for two‐dimensional SHTE mode seismoelectric and electroseismic waves modelling

AbstractA time‐domain finite‐element method based on an arbitrary quadrilateral mesh is proposed to simulate two dimensional seismoelectric and electroseismic waves in SHTE mode. By decoupling the electrokinetic coupling equation, we can solve seismic waves and electromagnetic waves independently. For the simulation of seismic wavefield, we utilize a more compact second‐order unsplit perfectly matched layer that is easier to implement in finite‐element methods. Moreover, to avoid errors caused by the quasi‐static approximation, we directly solve the full‐wave electromagnetic equations when simulating the electromagnetic wavefield. Our computational domain is discretized using arbitrary quadrilateral meshes, which offers possibilities in handling undulating terrain and complex anomalies in the underground. To ensure computational accuracy, we utilized biquadratic interpolation as our finite‐element basis functions, which provides higher precision compared to bilinear interpolation. We validate our time‐domain finite‐element method by comparing its results with analytical solutions for a layered model. We also apply our algorithm to the modelling of an underground aquifer and a complex anomalous hydrocarbon reservoir under undulating terrain.

Fabrication of MOF-rGO aerogels to enhance electromagnetic wave absorption by adjusting the morphology and structure of MOFs by electron transfer

Graphene and its derivatives have become the star materials in the field of electromagnetic wave (EMW) absorption, and have been widely studied because of their unique structure and excellent properties. However, the high electrical conductivity of graphene-based material leads to poor impedance matching performances, so it often needs to be annealed at high temperatures, which is a intricate procedure and cause the waste of energy. Herein, we develop a convenient strategy to synthesize metal organic framework-reduced graphene oxide (MOF-rGO) aerogels through facile hydrothermal and freeze drying procedure. Firstly, the excessive electrons on graphene can be transferred to MOF, in this way, no annealing is needed. Secondly, the morphology and structure of MOF can be regulated electronically to endow the material with rich heterojunction interfaces and enhance its interfacial polarization. Thirdly, the synthesized aerogels satisfy the requirements of thin thickness, low density and light weight. The fabricated Ni-MOF-rGO and FeNi-MOF-rGO aerogels exhibit remarkable EMW absorption performances with strong reflection loss (RL) and broad effective absorption band (EAB) at the thickness of 2.4 (−47.8 dB and 7.84 GHz) and 2.9 mm (−48.3 dB and 8.32 GHz) whereas the filling contents are just 5 %. Moreover, the attenuation capacity of the fabricated aerogels are verified through the radar-section simulation and the interfacial polarization loss are confirmed by the COMSOL analogue simulation. In a word, this work provides a new afflatus and inspiration for the design of graphene-based EMW absorption materials.

Bounding Volume Hierarchy-Assisted Fast SAR Image Simulation Based on Spatial Segmentation

In order to improve the simulation efficiency under the premise of ensuring the fidelity of synthetic aperture radar (SAR) simulation images, we propose a BVH-assisted fast SAR image simulation method based on spatial segmentation. The beam scanning model is established based on RD imaging geometric relation, and the bounding volume hierarchy (BVH) algorithm is used to assist in obtaining the time-varying latticed radiation and shadow areas within the radar beam, combining them with the real-time position of the sensors to complete the simulation of the electromagnetic (EM) wave transmission. The ray tracing algorithm is used to calculate the multiple backscatter fields of EM waves, including various material properties of the target surface. The SAR spatial traversal is adopted to spatially segment the latticed radiation area, and the compute unified device architecture (CUDA) kernel function is designed using the echo matrix cell method to make each cell of the target echo matrix as a subfield of the backscattering field, and the position of the echo matrix cell is traversed to obtain the target backscattering field. The target simulated echo is processed by the range Doppler (RD) imaging algorithm to obtain the SAR-simulated image. The simulation results show that compared with a CPU single-thread simulation, the simulation speed of the proposed method is significantly improved, and the SAR simulation image has high structural similarity with the real image, which fully verifies the effectiveness of the proposed method.

Magnetization reversal of ferromagnetic nanosample by circularly polarized radiation pulse under resonance condition

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.

Electromagnetic Landau Resonance: MMS Observations

AbstractTheoretical analysis has revealed a specific resonance that shares the same condition as Landau resonance, but instead involves wave electromagnetic fields rather than traditionally electrostatic fields. While this resonance, referred to as electromagnetic Landau resonance due to its properties, is considered significant for magnetospheric dynamics, rare reports or evaluations based on observations have been made thus far. Here, we present an event detected by the Magnetospheric Multiscale mission near the dayside magnetopause. During this event, ∼748‐eV protons are observed to be in resonance with a wave. Detailed data analysis demonstrates the resonant velocity closely matches the wave's parallel phase speed, which, combined with the significant work done by wave perpendicular electric field, confirms this interaction as electromagnetic Landau resonance. Further investigation indicates these protons are being secularly accelerated within this resonance. Consequently, our observations provide the first empirical evidence supporting the previously suggested theoretical importance of the electromagnetic Landau resonance.

Special Relativity in Terms of Hyperbolic Functions with Coupled Parameters in 3+1 Dimensions

This paper presents a method for parameterizing new Lorentz spacetime coordinates based on coupled parameters. The role of symmetry in rapidity in special relativity is explored, and invariance is obtained for new spacetime intervals with respect to the Lorentz transformation. Using the Euler–Hamilton equations, an additional angular rapidity and perpendicular rapidity are obtained, and the Hamiltonian and Lagrangian of a relativistic particle are expanded into rapidity spectra. A so-called passage to the limit is introduced that makes it possible to decompose physical quantities into spectra in terms of elementary functions when explicit decomposition is difficult. New rapidity-dependent Lorentz spacetime coordinates are obtained. The descriptions of particle motion using the old and new Lorentz spacetime coordinates as applied to plane laser pulses are compared in terms of the particle kinetic energy. Based on a classical model of particle motion in the field of a plane monochromatic electromagnetic wave and that of a plane laser pulse, rapidity-dependent spectral decompositions into elementary functions are presented, and the Euler–Hamilton equations are derived as rapidity functions in 3+1 dimensions. The new and old Lorentz spacetime coordinates are compared with the Fermi spacetime coordinates. The proper Lorentz groups SO(1,3) with coupled parameters using the old and new Lorentz spacetime coordinates are also compared. As a special case, the application of Lorentz spacetime coordinates to a relativistic hydrodynamic system with coupled parameters in 1+1 dimensions is demonstrated.

Ac Hall Effect and Photon Drag of Superconducting Condensates.

We suggest a theoretical description of the photogalvanic phenomena arising in superconducting condensates in the field of electromagnetic wave. The ac Hall effect and photon drag are shown to originate from the second-order nonlinear response of superconducting carriers caused by the suppression of their concentration due to the combined influence of the electron-hole asymmetry and charge imbalance generated by the incident electromagnetic wave. Starting from the time-dependent Ginzburg-Landau theory with the complex relaxation constant, we develop a phenomenological description of these phenomena and investigate the resulting behavior of the dc supercurrent and second harmonic induced by microwave radiation incident on a superconductor surface.

Radiation Intensity of a Charged Particle in the Field of a Polarization-Modulated Electromagnetic Wave

Radiation Intensity of a Charged Particle in the Field of a Polarization-Modulated Electromagnetic Wave

Mapping of Electromagnetic Field Radiation Intensity in the JL Base Transceiver Station (BTS) Area. Kenangan 05 and the Impact of Health in Society


 
 
 
 Electromagnetic waves are a type of wave phenomenon. Electromagnetic waves are transverse waves that arise due to changes in electric fields and magnetic fields that oscillate with each other. Electromagnetic waves can be generated, one of the ways, from BTS towers so that they can produce intense electromagnetic field radiation. Health problems resulting from exposure to electromagnetic wave radiation cannot be felt directly. However, the longer you are exposed to electromagnetic wave radiation, the more dangerous it will be to your body's health. The aim of this research is to carry out mapping from measuring the intensity of electromagnetic field radiation in the BTS area and to determine the health impact of large electromagnetic field radiation on the surrounding community. Data processing in this research was carried out using quantitative techniques and qualitative techniques, namely by measuring the intensity of the electric field and magnetic field of electromagnetic waves and evaluating the results of the intensity of electromagnetic field radiation as well as conducting interviews as a public health survey. The data obtained in this research was processed using ArcGis and Surfer software for mapping results. Based on the evaluation and mapping results, it shows that the intensity of electromagnetic field radiation is still below the threshold value according to the 2020 ICNIRP standards. Based on the results of this research, there are no significant health effects occurring in the surrounding community.
 
 
 

Analysis and research on the teaching reform of electromagnetic wave and microwave technology under the background of new business form

This paper studies the higher education in the national economic form change, college students learning state new form, education and industry, education information under the background, for profound theory, experimental equipment expensive, experimental conditions, in the student theory of weak, try to need the education teaching reform direction and reform measures. Among them, the education and teaching reform of microwave technology curriculum was piloted as an example. For the weak theoretical foundation of electromagnetic field and insufficient mathematical foundation, the course adopts the strategy of light theory requirement, heavy phenomenon cognition, and guiding the application of knowledge to practice. Through virtual simulation, the invisible electromagnetic field and electromagnetic wave make it easier for students to understand the knowledge context to form the knowledge system; Through online and offline mixed teaching, stress response teaching, promote students 'participation in classroom teaching, improve students' independent thinking ability and judgment and analysis ability, attract students' attention in classroom learning, and interest in the corresponding knowledge content. And then promote the students' self-study ability, research ability and design ability.

RFID car using arduino mega 2560 by dijkstras algorithm

This paper introduces a module which is used to transport goods or people from one place to another without any driver assistant. It is mainly used in big industries to save the time and energy. This module is built around an RFID sensor. RFID technology uses fields of electromagnetic waves to track and monitor tags attached to objects. When triggered with a field of electromagnetic waves investigate pulse from an adjacent RFID reader device, this tag delivers digital information back to the reader, which is often an inventory number. This number can be used to keep track of inventories. The sensors collect the data and sends to the main algorithm and then it takes the decision which way to go, we implemented our car to be completely automated and does not required any instructions from human. To achieve this we have chosen the shortest path algorithm know as Dijkstra's algorithm.

3D multifunctional porous pine carbon aerogels coupled with highly dispersed CoFe nanoparticles for robust electromagnetic wave response

Functional carbonaceous materials with controllable morphology, low apparent density, large surface area, and high porosity starting from natural precursors using environmentally friendly processes are an appealing topic in the electromagnetic wave (EMW) field. In this work, renewable pine woods with ordered pore channels are selected to load highly dispersed CoFe alloy nanoparticles formed by in-situ pyrolysis reaction between Fe3O4 nanospheres and ZIF-67 nanoparticles. The constructed three-dimensional (3D) porous CWA-CoFe-NC aerogel inherits the characteristics of highly dispersed small CoFe alloy nanoparticles, porous carbon aerogel with rectangular honeycomb-like structure, and abundant N heteroatoms. Therefore, CWA-CoFe-NC aerogel achieves an excellent EMW absorption performance with reflection loss (RL) values of −61.6 and −58.2 dB at matching thicknesses of 3.7 and 1.2 mm, respectively. Benefiting from the reasonable design of the composite structure and composition, 3D porous aerogel also enables great potential for multifunctional applications. Particularly, good lightweight and mechanical properties are realized in the CWA-CoFe-NC aerogels due to their ordered pore channels and abundant rectangular pores. Furthermore, good flame retardant performance can ensure the serviceability of the target device in high/low-temperature environments. In addition, CWA-CoFe-NC aerogels show good thermal stability and thermal management characteristics. This work provides a novel and effective method for the preparation of lightweight, high-performance, and multifunctional EMW absorbers.

Interface detection of near-borehole stratified formation under different permeabilities based on seismoelectric logs: A finite-difference modeling

Seismoelectric wavefields arising from electrokinetic effects in fluid-filled porous media are valuable for reservoir exploration. Identifying the formation interface is crucial for reservoir exploration. In this study, we developed a finite-difference (FD) algorithm for calculating borehole seismoelectric wavefields and proposed the use of seismoelectric logs to detect permeability interfaces in near-borehole formations. The borehole-formation acoustic wave and its induced electromagnetic (EM) wavefield are calculated separately using the FD algorithm where the feedback effect of the EM wavefield on the acoustic wave is disregarded. We find that various acoustic-guided waves propagating along the borehole wall (P, S, and Stoneley waves) could generate significant EM waves at the formation interfaces with varying permeabilities. At the horizontal interfaces, the acoustic field does not generate significant interface signals. The EM wave induced by the Stoneley wave is clearly observed in the borehole, whereas those induced by the P and S waves are barely distinguishable. At the tilted interfaces, the Stoneley-wave-induced EM wave is more noticeable, and even P- and S- waves-induced EM waves are clearly observed. The mud cake and invaded zone near the borehole wall have little influence on the interface detection of near-borehole formations using seismoelectric logs. The collar wave during sonic logging while drilling, is a nerve-wracking, noisy signal that can significantly impede the extraction of P- and S-wave velocities. However, the collar wave can generate significant interfacial EM signals, thereby allowing for the detection of formation interfaces using the collar wave. Theoretical calculation shows that compared with the acoustic field in sonic logging, the electric field in seismoelectric logging has more advantages in stratified interface identification. It shows that seismoelectric logging has potential application value in the detection of the formation interface.

Large Microsphere Structure of a Co/C Composite Derived from Co-MOF with Excellent Wideband Electromagnetic Microwave Absorption Performance.

In the field of electromagnetic wave (EMW) absorption, carbon matrix materials based on metal-organic frameworks (MOFs) have drawn more interest as a result of their outstanding advantages, such as porous structure, lightweight, controlled morphology, etc. However, how to broaden the effective absorption bandwidth [EAB; reflection loss (RL) ≤ -10 dB] is still a challenge. In this paper, large microsphere structures of a Co/C composite composed of small particle clusters were successfully prepared by the solvothermal method and annealing treatment. At a filling ratio of 40 wt %, the Co/C composite shows attractive microwave absorption (MA) performance after being annealed at 600 °C in an atmosphere of argon. With an EAB of 6.32 GHz (9.92-16.24 GHz) and a thickness of just 2.57 mm, the minimum RL can be attained at -54.55 dB. Most importantly, the EAB can attain 7.12 GHz (10.88-18.0 GHz) when the thickness is 2.38 mm, which is larger than that of the majority of MOF-derived composites. The superior MA performance is strongly related to excellent impedance matching and a higher attenuation constant. This study provides a simple strategy for synthesizing a MOF-derived Co/C composite with a wide EAB.

Analysis of GPR Data Characteristics of Drainage Pipe and Cavity Coexisting

Drainage pipe leakage usually causes roadbed loosening and even collapse. Therefore it is of great significance to accurately locate and repair the leakage area. This paper studies the use of GPR to carry out the detection of drainage pipe leakage area, aiming to solve the problem of unclear electromagnetic wave field response characteristics when drainage pipes and cavities coexist. First, we used gprMax to carry out numerical simulation experiments to obtain the electromagnetic wave field response characteristics when a square cavity exists around a circular drainage pipe. Subsequently, similar data characteristics to the numerical simulation were obtained through field detection, and the area was confirmed to be a cavity caused by drainage pipe leakage through drilling. This study shows that the use of numerical simulations can provide a basis for the identification of cavities caused by drainage pipe leakage in GPR data.

Efficacy of Extracorporeal Shock Wave and Pulse Electromagnetic Field Therapies in Calcaneal Spurs.

Various treatment methods are available for calcaneal spur, which can cause disability. Objective: To evaluate the efficacy of pulsed electromagnetic field therapy (PEMFT) added to extracorporeal shock wave therapy (ESWT) on pain and functional capacity in treating calcaneal spurs. Patients with calcaneal spurs who were recommended ESWT or ESWT+PEMFT and whose Foot Function Index (FFI) and visual analogue scale (VAS) values were available in their records were retrospectively analyzed. The two groups were ESWT (n=35) and ESWT+PEMFT (n=40). FFI and VAS scores were obtained from their records before treatment, after treatment, and in the third month after treatment. The two groups were similar regarding their pre-treatment FFI and VAS scores. In intra-group evaluation, statistically significant decreases were found in terms of the FFI pain, disability, and activity limitation and VAS scores in both groups after treatment and in the third month after treatment compared to the pre-treatment period. In the comparison between the groups, the post-treatment and post-treatment third-month FFI pain, disability, and activity limitation and VAS scores were significantly lower in the PEMFT+ESWT group than the ESWT group (P<0.001). A calcaneal spur is a condition that can cause pain and functional limitation in patients. Various studies have demonstrated the efficacy of ESWT in the treatment of calcaneal spurs. In our study, we observed that PEMFT added to ESWT significantly improved the pain and functionality of the patients. Further studies are needed to evaluate the efficacy of PEMFT in calcaneal spurs.

Monitoring Preferential Flow of Water in Sand Using Thermoacoustics Wave Imaging

AbstractAccurate predictions of fluid flow, mass transport, and reaction rates critically impact the efficiency and reliability of subsurface exploration and sustainable use of subsurface resources. Quantitative dynamical sensing and imaging can play a pivotal role in the ability to make such predictions. Geophysical thermoacoustic technology has the potential to provide the aforementioned capabilities, since it builds upon the principle that electromagnetic and mechanical wave fields can be coupled through a thermodynamic process. In this letter, we present laboratory experiments featuring the efficacy of thermoacoustic imaging in the monitoring of preferential flow of water in porous media. Our laboratory experimental equipment can be readily packaged in a form factor that fits in a borehole, and the use of multiple acoustic transducers—which can be combined with volumetric coding techniques—has the potential to provide quasi‐real‐time imaging (0.5 Hz video rate) of regions in close proximity (a few meters) of an open field well.

The computation of Lie point symmetry generators, modulational instability, classification of conserved quantities, and explicit power series solutions of the coupled system

The well-known Chaffee–Infante reaction hierarchy is examined in this article along with its reaction–diffusion coupling. It has numerous variety of applications in modern sciences, such as electromagnetic wave fields, fluid dynamics, high-energy physics, ion-acoustic waves in plasma physics, coastal engineering, and optical fibres. The physical processes of mass transfer and particle diffusion might be expressed in this way. The Lie invariance criteria is taken into consideration while we determine the symmetry generators. The suggested approach produces the six dimensional Lie algebra, where translation symmetries in space and time are associated to mass conservation and conservation of energy respectively, the other symmetries are scaling or dilation. Additionally, similarity reductions are performed, and the optimal system of the sub-algebra should be quantified. There are an enormous number of exact solutions can construct for the traveling waves when the governing system is transformed into ordinary differential equations using the similarity transformation technique. The power series approach is also utilized for ordinary differential equations to obtain closed-form analytical solutions for the proposed diffusive coupled system. The stability of the model under the limitations is ensured by the modulation instability analysis. The reaction diffusion hierarchy’s conserved vectors are calculated using multiplier methods using Lie Backlund symmetries. The acquired results are presented graphically in 2-D and 3-D to demonstrate the wave propagation behavior.

Analysis and Application of the Electromagnetic Wave Propagation, Fields, and Dispersion Relation in an Elliptical Chiro Plasma Waveguide Immersed in Magnetized Plasma

AbstractThis research proposes and investigates an elliptical waveguide filled with chiro plasma as its core and magnetized plasma as its clad region. The clad region is in the constant infinite magnetic field, and its direction is the same as the wave propagation in the chiro plasma elliptical waveguide. The electromagnetic wave propagation in the considered waveguide is studied. The expressions for electromagnetic field components in the chiro plasma core and magnetized plasma cladding are derived. The dispersion relations for the hybrid modes are calculated considering appropriate boundary conditions at the chiro plasma and magnetized plasma interface. The behavior of the energy flux and the dispersion curves are numerically and graphically studied. It is seen that the magnitude of the power density decreases with the increase of the cyclotron frequency and it increases with the increase of the plasma frequency and supports power flow in the backward direction for the considered mode. Furthermore, it is shown higher values of the chirality parameter cause the magnitude of the power flux to increase in the backward direction.