Electromagnetic Wavelength Research Articles

SSGAN: Cloud removal in satellite images using spatiospectral generative adversarial network

Satellite data’s reliability, uniformity, and global scanning capabilities have revolutionized agricultural monitoring and crop management. However, the presence of clouds in satellite images can obscure useful information, rendering them difficult to infer. Aiming at the problem of cloud cover, this study presents a SpatioSpectral Generative Adversarial Network (SSGAN) approach for effectively eliminating cloud cover from multispectral satellite images. It utilizes the Synthetic Aperture Radar (SAR) images as complementary information with the optical images from the Sentinel-2 satellite. The proposed model exploits feature extraction by sub-grouping the 13 channels of Sentinel-2 images based on their electromagnetic wavelength. Experimentally, we demonstrated that the proposed SSGAN model surpasses conventional and state-of-the-art (SOTA) methods and can reconstruct regions obscured by clouds. The subgrouping optimized the utilization of sensor information and improved the performance metrics for reconstructed images. Compared to the state-of-the-art (SOTA) approach, the SSGAN model demonstrates higher performance, achieving a mPSNR of 32.771, mSSIM of 0.880, and correlation coefficient (CC) of 0.889. The SSGAN model was further evaluated under varying conditions, including scenarios without the inclusion of SAR data, where it achieved a mPSNR of 26.825, mSSIM of 0.726, and CC of 0.615. Adding SAR images into the model significantly enhanced its performance, resulting in a mPSNR of 29.932, mSSIM of 0.857, and CC of 0.735. These results indicate that higher mPSNR, mSSIM, and CC values correspond to better image reconstruction quality. Our method enhances the usability of satellite data for crop mapping, crop health monitoring, and crop yield prediction.

Slot-Loaded Vivaldi Antenna for Biomedical Microwave Imaging Applications: Influence of Design Parameters on Antenna's Dimensions and Performances.

This paper demonstrates the design steps of a slot-loaded Vivaldi antenna for biomedical microwave imaging applications, showing the influence of the design parameters on the antenna's dimensions and performances. Several antenna miniaturization techniques were taken into consideration during the design: reduction in the electromagnetic wavelength by using a high-permittivity substrate material (relative permittivity ϵr=10.2), the placement of the antenna inside a coupling medium (ϵr=23), and the elongation of the current path by etching slots on each side of the radiator to reduce the antenna's lowest resonant frequency without increasing its physical dimensions. Moreover, an analysis of different antenna slot design scenarios was performed considering different slot lengths, inclination angles, positions, and numbers. Considering the frequency range of microwave imaging (i.e., about 500 MHz-5 GHz) and the array arrangement typical of microwave imaging, the best design was chosen. Finally, the antenna was fabricated and its performances in the coupling medium were characterized. The simulation and measurement results showed good agreement between each other. In comparison with literature antennas, the one developed in this work shows wide bandwidth and compact dimensions.

Plasmon-mediated photocatalytic conversion in Au or Ag nanorod aggregates by surface-enhanced Raman spectroscopy

Plasmonic nanoparticles (NPs) hold considerable potential as photocatalysts owing to their robust light–matter interactions across diverse electromagnetic wavelengths, which significantly influence the photophysical characteristics of the adjacent molecular entities. Despite the widespread use of noble-metal NPs in surface-enhanced Raman scattering (SERS) applications, little is known about the kinetics of nanoparticle aggregation and how it affects their configurations. This study investigates the plasmon-driven photochemical conversion of 4-nitrobenzenethiol (NBT) to 4,4′-dimercaptoazobenzene (DMAB) on Au and Ag nanorods (NRs) through SERS. Significantly, photoconversion phenomena were observed on Ag NRs but not on Au NRs upon laser excitation at 633 nm. Finite-difference time-domain simulations revealed the presence of stronger electromagnetic fields on Ag NRs than on Au NRs. The aspect ratios and gaps between individual NPs in dimer configurations were determined to elucidate their effects on electromagnetic fields. The Ag NR dimer with an end-to-end configuration, an aspect ratio of 3.3, and a 1-nm gap exhibited the highest enhancement factor of 1.05 × 1012. Our results demonstrate that the primary contribution from diverse configurations in NR aggregates is the end-to-end configuration. The proposed NP design with adjustable parameters is expected to advance research in plasmonics, sensing, and wireless communications. These findings also contribute to the understanding of plasmon-driven photochemical processes in metallic nanostructures.

Exploring Quantized Massless Photonic Wave-Particle Duality, Inertial Mass Resistance to Motion, and the Speed of Light as Representations of a Higher Dimensional Hyperspace Axis within Subspace Field Unification

This paper explores the potentially interlinked, multidimensional nature of three fundamental qualities of reality. First, wave-particle duality is examined as an intrinsic extension of the fundamental two-dimensional electromagnetic wavelength, which permeates into a three-dimensional quantum manifestation of photonic particles. Second, the speed of light is considered as a limiting factor imposed by a multidimensional hyperspatial subspace ether grid, where the tensile locality restricts light's travel. Third, the movement of mass-carrying particles through this subspace ether grid is analyzed as being responsible for inertial resistance—specifically, resistance to changes in motion, including acceleration, deceleration, and changes in relative velocity.This paper then postulates that the massless motion of photonic energy packets at the speed of light, and the inertial resistance of mass-carrying hadronic particles to changes in relative motion, are opposite dimensional aspects of a unified subspace field theory. These aspects, though seemingly distinct, are proposed to occupy opposing sides of the same intersecting hyperspatial axis, within a higher-dimensional etheric reality.

Minitype Arrays of Acoustically Actuated Magnetoelectric Antennas for Magnetic Induction Communication

The magnetoelectric (ME) antennas rely on the mechanical movement of magnetic dipoles, making it possible to break the constraints on physical dimensions decided by the wavelength of the electromagnetic wavelength. The ME antennas achieve super-low frequency (SLF) communications with a smaller size to provide a novel solution for long-range, underwater, and underground communications; navigation over the horizon; and geological exploring. As a result, further theoretical research and optimization of ME antennas have been an open challenge for decades. Here, we report on minitype arrays of acoustically actuated ME antenna and their more rigorous equivalent circuits. These arrays of ME antenna adjust amplitude-frequency response through the mechanical regulation method. The mechanical parameters of ME antennas in the arrays result in regulating amplitude-frequency response, such as working frequency, fractional bandwidth, and intensity of magnetic induction. Our work provides a more accurate theoretical model and diverse array form over state-of-the-art ME antenna arrays. The frequency, fractional bandwidth, and magnetic induction strength of the ME antenna arrays were achieved to be adjustable in the ranges of 84 to 181 Hz, 3.9% to 8.3%, and two to four times, respectively. In addition, we have calculated the attenuation characteristics of ME antennas and their minitype arrays in seawater. The results show that the ME antenna array described in this manuscript is able to enhance the radiation intensity and information-loading capability, which has a positive potential for application in SLF communication systems.

Deep jointly optical spectral band selection and classification learning

Spectral data provide material-specific information across a broad electromagnetic wavelength range by acquiring numerous spectral bands. However, acquiring such a significant volume of data introduces challenges such as data redundancy, long acquisition times, and substantial storage capacity. To address these challenges, band selection is introduced as a strategy that focuses on only using the most significant bands to preserve spectral information for a specific task. State-of-the-art methods focus on searching for the most significant bands from previously acquired data, regardless of the optical system and the classification model. Nevertheless, some deep-learning methods, such as end-to-end frameworks, allow the design of optical systems and the learning of the classification network parameters. In this paper, we model the optical band selection as a trainable layer that is coupled with a classification network, where the parameters are learned in an end-to-end framework. To guarantee a physically implementable system, we proposed two regularization terms in the training step to promote binarization and also the number of the selected bands, as we need to provide the conditions to design the physical element where the light passes through. The proposed method provides better performance than state-of-the-art band selection methods for three different spectral datasets under the same conditions.

Laser Ablation for the Synthesis of Cu/Cu2O/CuO and Its Development as Photocatalytic Material for Escherichia coli Detoxification.

Advanced Oxidation Processes (AOPs) offer promising methods for disinfection by generating radical species like hydroxyl radicals, superoxide anion radicals, and hydroxy peroxyl, which can induce oxidative stress and deactivate bacterial cells. Photocatalysis, a subset of AOPs, activates a semiconductor using specific electromagnetic wavelengths. A novel material, Cu/Cu2O/CuO nanoparticles (NPs), was synthesized via a laser ablation protocol (using a 1064 nm wavelength laser with water as a solvent, with energy ranges of 25, 50, and 80 mJ for 10 min). The target was sintered from 100 °C to 800 °C at rates of 1.6, 1.1, and 1 °C/min. The composite phases of Cu, CuO, and Cu2O showed enhanced photocatalytic activity under visible-light excitation at 368 nm. The size of Cu/Cu2O/CuO NPs facilitates penetration into microorganisms, thereby improving the disinfection effect. This study contributes to synthesizing mixed copper oxides and exploring their activation as photocatalysts for cleaner surfaces. The electronic and electrochemical properties have potential applications in other fields, such as capacitor materials. The laser ablation method allowed for modification of the band gap absorption and enhancement of the catalytic properties in Cu/Cu2O/CuO NPs compared to precursors. The disinfection of E. coli with Cu/Cu2O/CuO systems serves as a case study demonstrating the methodology's versatility for various applications, including disinfection against different microorganisms, both Gram-positive and Gram-negative.

Simulation-based design of 1-D copper nanograting device for sensing application by studying electromagnetic properties on Cu/Air interface

Sensing devices has been an interesting area of study because of their immense application in practical life. In the present work, the extraordinary optical transmission (EOT) along with surface plasmon polaritons (SPPs) excitation at the metal/ dielectric interface is investigated RF-module of COMSOL Multiphysics 5.3a has been used to investigate copper (Cu) nanograting structure on the glass substrate in periodic arrangement of 1-dimensional (1D). The visible-infrared electromagnetic wavelength of 400–900 nm has been used to excite the SPPs at the interface and a light port is provided from the substrate side. The optimum EOT has been investigated at transmission spectra of 0th order. During this process thickness of the slit is fixed at 50 nm, the periodicity of the unit cell is fixed at 700 nm, and the width of the slit changed to check its effect on the EOT. Additionally, phenomena of near field investigation have also used to explore the transmission-based performance of field at thespecificboundary of copper (Cu) and airwhich confirm spectraoutcomesof transmission thorough the fabricated device. The optimum value of EOT foundwhenthe width of slit isat250 nm for the Cu/air interface.The deviceused for this purpose is modeled in COMSOL. Along the EOT the SPPs phenomena is also investigated by using present modeled device.These phenomena are observed by studying the electric and magnetic parts of the device that models the Cu/Air interface. We tested it with different slit widths ranging from 50-450 nm. The coupling efficiency and sensitivity of Cu/Air 1D device design at optimum slit width of 250 nm calculated. Such devices are increasingly applicable in bio photonics sensing of DNA structure, in vivo study of the internal structure of the body, imaging, surface chemical reaction, environmental remediation, and in various solar cell industries (plasmonic solar cell).

Gain Enhancement and Ground Plane Immunity of Mechanically Driven Thin‐Film Bulk Acoustic Resonator Magnetoelectric Antenna Arrays

AbstractCompact, conformal antennas with ground plane immunity and high gain are crucial to IoT, 5G, and biomedical applications. Conventional electrical antennas suffer large size, detuned impedance, and degraded gain and radiation efficiency on a ground plane as they operate on electromagnetic resonance and use electric dipole for radiation. Utilizing electromechanical resonance, magnetoelectric(ME) coupling, and magnetic dipole radiation in magnetostrictive/piezoelectric heterostructures, ME antennas exhibit ultra‐compact sizes comparable to acoustic wavelength and enhanced radiation performance on a ground plane. This study first utilizes parallel and series antenna array topology to achieve a profound gain and radiation efficiency enhancement without degrading impedance mismatch and quality factor of ME resonators. Notably, by increasing the array element number, 10 dBi gain enhancement is achieved in 3 × 3 thin‐film bulk acoustic resonator (FBAR) ME antenna array, reaching a peak antenna gain of −17.3 dBi. Unlike conventional antenna arrays, ME antenna arrays enhance radiation efficiency without affecting directivity, owing to ultra‐compact dimensions much less than one‐quarter of electromagnetic wavelength. Their ground plane immunity and 3 dB gain enhancement on ground planes with different shapes are also demonstrated. The demonstrated ME antenna arrays are outstanding platform‐independent ultra‐compact high‐gain conformal antenna candidates for wireless communication, wireless power transfer, and portable electronic and biomedical devices.

Parameter Inference of a State-of-the-Art Physical Afterglow Model for GRB 190114C

A state-of-the-art semi-analytic gamma-ray burst (GRB) afterglow model with synchrotron self-Compton (SSC) emission has been applied for the first time for parameter inference using real GRB data. We analyzed the famous GRB 190114C as a case study. GRB 190114C, characterized by its long duration and high luminosity, was observed by many ground-based and orbiting telescopes spanning a wide range of electromagnetic wavelengths, from radio to GeV gamma rays. We used two advanced algorithms for inference: a nested sampling algorithm called UltraNest and an MCMC algorithm emcee. Evoking the standard afterglow model, the inference result and the best-fit values lead to an initial bulk Lorentz factor (a rough estimate of Γ=526), which aligns with the values often seen in GRBs identified by the Fermi-LAT instrument. Similarly to the best-fit values of other studies in the literature, the derived values of microphysical parameters, the circumburst density, and the kinetic efficiency are consistent with those found after modeling the multi-wavelength observations in GRB 190114C. We show that the SSC from the forward-shock region can only describe the highest-energy photons above a few GeVs.

ОПТИЧНА СПЕКТРОСКОПІЯ ДЕТЕКТОРНИХ ВИСОКООМНИХ МОНОКРИСТАЛІВ CdTe (111) ТА ТВЕРДИХ РОЗЧИНІВ Cd 1-x Zn x Te (х= 0,1)

Cadmium telluride is used for the manufacture of uncooled gamma radiation detectors, and solid solutions of Cd 1-x Zn x Te (x=0.1) are used for the manufacture of X-ray and gamma radiation detectors. The study of the effect of doping on the physical properties of semiconductors is relevant both for experimenters and for the theoretical substantiation of physical processes. This paper presents the results of the study of optical reflection spectra in the spectral range (0,2-1,7) . 10 -6 m and transmittance in the region of the fundamental optical transition E 0 of high-resistivity CdTe single crystals of (111) orientation with resistivity ρ = (2÷5)·10 9 Ohm∙cm doped with chlorine, as well as solid solutions of Cd 1-x Zn x Te (x = 0.1) with resistivity ρ = (5 ÷30)∙10 9 Ohm∙cm. Since the optical reflection coefficient R = f (λ) is related to the optical transmittance T = f (λ) and absorption D = f (λ) by the ratio R+T+D=1 (with the light (electromagnetic) wave scattering in the studied samples not taken into account), the absorption spectra D=1-(R+T) versus the light (electromagnetic) wavelength λ were also constructed in this work. It is determined that the energy of the fundamental optical transition E 0 of the studied materials at T = 300 K is as follows: for CdTe - 1.44 eV; and for Cd 1-х Zn х Te (x = 0.1) - 1.5 eV. The energy relaxation time of free charge carriers τ for p-CdTe (111) single crystals and Cd 1-х Zn х Te (x = 0.1) solid solutions was estimated to be 1.343-10 -14 s and 0,878·10 -14 s, respectively. The effective "optical" mobility for single crystals of p-CdTe (111) and solid solutions of Cd 1-х Zn х Te (x = 0.1) is 274 . 10 -4 ; 179,5 . 10 -4 , respectively. It has been shown that the investigated crystals are of high (detector) quality, which is crucial for the manufacture of highly sensitive and high-resolution ionising radiation sensors. The practical value of the obtained results lies in the determination of electronic and physical parameters of technically important semiconductors CdTe and Cd 1-х Zn х Te (x=0.1).

ВИКОРИСТАННЯ РЕЗУЛЬТАТІВ РОБОТИ МЕТЕОРНОГО АПАРАТУРНО-ПРОГРАМНОГО КОМПЛЕКСУ В ОСВІТНЬОМУ ПРОЦЕСІ ЗІ СТУДЕНТАМИ ФІЗИКО-МАТЕМАТИЧНИХ СПЕЦІАЛЬНОСТЕЙ ЗАКЛАДІВ ВИЩОЇ ОСВІТИ

Features of meteor fixation methods by organizing a network of corresponding observation points – permanently operating observation stations located on the territory of Ukraine with appropriate technical and software for basic and one-way observations of meteors in the radio range of electromagnetic wavelengths are presented, as well as the results of involving students in the analysis of work results meteor hardware and software complex, as a component of the Ukrainian meteor ob servation network. The principle of operation of a separate meteor hardware and softwar e complex for observing meteors in the radio range of electromagnetic waves using the method of direct scattering on meteor trails of signals from powerful FM radio broadcasting stations with the possibility of further processing and presentation of data by students of physical and mathematical specialties of higher education institutions is considered. The results of statistical data processing of meteor invasions and their graphic representation by students of physical and mathematical specialties are described. The seventh reception station in the city of Kyiv (student campus of NUBiP of Ukraine) – the seventh meteor hardware and software complex, as a component of the Ukrainian meteor observation network – has been put into operation.

Far-Infrared Ameliorates Pb-Induced Renal Toxicity via Voltage-Gated Calcium Channel-Mediated Calcium Influx.

Far-infrared (FIR), characterized by its specific electromagnetic wavelengths, has emerged as an adjunctive therapeutic strategy for various diseases, particularly in ameliorating manifestations associated with renal disorders. Although FIR was confirmed to possess antioxidative and anti-inflammatory attributes, the intricate cellular mechanisms through which FIR mitigates lead (Pb)-induced nephrotoxicity remain enigmatic. In this study, we investigated the effects of FIR on Pb-induced renal damage using in vitro and in vivo approaches. NRK52E rat renal cells exposed to Pb were subsequently treated with ceramic-generated FIR within the 9~14 μm range. Inductively coupled plasma mass spectrometry (ICP-MS) enabled quantitative Pb concentration assessment, while proteomic profiling unraveled intricate cellular responses. In vivo investigations used Wistar rats chronically exposed to lead acetate (PbAc) at 6 g/L in their drinking water for 15 weeks, with or without a concurrent FIR intervention. Our findings showed that FIR upregulated the voltage-gated calcium channel, voltage-dependent L type, alpha 1D subunit (CaV1.3), and myristoylated alanine-rich C kinase substrate (MARCKS) (p < 0.05), resulting in increased calcium influx (p < 0.01), the promotion of mitochondrial activity, and heightened ATP production. Furthermore, the FIR intervention effectively suppressed ROS production, concurrently mitigating Pb-induced cellular death. Notably, rats subjected to FIR exhibited significantly reduced blood Pb levels (30 vs. 71 μg/mL; p < 0.01), attenuated Pb-induced glomerulosclerosis, and enhanced Pb excretion compared to the controls. Our findings suggest that FIR has the capacity to counteract Pb-induced nephrotoxicity by modulating calcium influx and optimizing mitochondrial function. Overall, our data support FIR as a novel therapeutic avenue for Pb toxicity in the kidneys.

The Contribution of the Pore Size of Titanium DC (Direct Current) Sputtered Condensation Polymer Materials to Electromagnetic Interruption and Thermal Properties

Using special materials has been in the spotlight, along with their multifunctional demands, research on electromagnetic interruption, thermal characteristics, biosignal sensors, secondary batteries, etc. In this study, titanium was sputtered into a condensation polymer material and considered in depth in terms of electromagnetic interruption, thermal properties, infrared blocking, etc. As a result of observing the electromagnetic wave shielding effect, the electromagnetic wavelength value decreased from 168.0 to 42.7 to 64.0 when titanium DC sputtered film samples were placed in front of the electromagnetic wave source. The titanium DC sputtered samples significantly reduced electrical resistance compared to the untreated samples. In addition, the IR transmittances of the titanium sputtered specimens were decreased compared to the untreated specimens. When only the cross-section was treated with titanium sputtering and the titanium surface was directed toward the infrared irradiator, the infrared permeability was 64.3 to 0.0%. After taking an infrared thermal image, ΔH, ΔV, ΔS, ΔY, ΔCr, and ΔCb values were calculated. It is believed that the titanium DC sputtered polyamide materials produced in this study can be used for high-functional protective clothing, sensors by applying electromagnetic interruption, IR blocking, and stealth functions.

Multimessenger parameter inference of gravitational-wave and electromagnetic observations of white dwarf binaries

ABSTRACT The upcoming Laser Interferometer Space Antenna (LISA) will detect a large gravitational-wave foreground of Galactic white dwarf binaries. These sources are exceptional for their probable detection at electromagnetic wavelengths, some long before LISA flies. Studies in both gravitational and electromagnetic waves will yield strong constraints on system parameters not achievable through measurements of one messenger alone. In this work, we present a Bayesian inference pipeline and simulation suite in which we study potential constraints on binaries in a variety of configurations. We show how using LISA detections and parameter estimation can significantly improve constraints on system parameters when used as a prior for the electromagnetic analyses. We also provide rules of thumb for how current measurements will benefit from LISA measurements in the future.

The Impact of Water Availability on the Discriminative Status of Nitrogen (N) in Sugar Beet and Celery Using Hyperspectral Imaging Methods

A pot experiment was conducted to determine the impact of water availability on the discriminatory status of nitrogen (N) in plants using hyperspectral imaging. Nitrogen deficiency causes a significant decrease in chlorophyll concentration in plant leaves regardless of water availability. Five different classification algorithms were used to discriminate between nitrogen concentrations in plants at different levels of water availability. Several statistical parameters, including kappa and overall classification accuracy for calibration and prediction, were used to determine the efficiency and accuracy of the models. The Random Forest model had the highest overall accuracy of over 81% for sugar beet and over 78% for celery. Additionally, characteristic electromagnetic wavelengths were identified in which reflectance correlated with nitrogen and water content in plants could be recorded. It was also noted that the spectral resolution between the N and High Water (HW)/Low Water (LW) treatments was lower in the short-wave infrared (SWIR) region than in the visible and near-infrared (VNIR) region.

Influence of Deposition Voltage on Strontium Sulphide Doped Silver for Optoelectronic Application

In the research electrochemical deposition technique was use in deposition of undoped SrS and doped SrS with silver were 0.01 mol of thioacetamide (C2H5NS), 0.1 mol of strontium chloride hexahydrate (SrCl2.6H2O), and 0.01 mol of silver nitrate (AgNO3) were utilized as the cationic, anionic, and dopant concentrations. The XRD spectra of the SrS and SrS doped silver showed prominent crystalline peaks at angles of 26.69°, 37.97°, 51.39°, and 65.56° for SrS and 26.42°, 33.42°, 37.98°, and 51.32° for SrS/Ag, respectively, with corresponding diffraction planes (111), (112), (200), and (211). However, the diffraction pattern shows that the peak intensity increases as the deposition voltage increases. The undoped SrS material morphology has a clove-like substance with precipitate; the large nano grain on the substrate's surface exhibits photon absorption but shows no traces of pinholes. When doped SrS is deposited at various precursor voltages, it forms uniform surfaces devoid of pinholes. The cell also penetrates the substrate being used for the deposition, as seen by the elemental makeup of the films. It was observed that SrS/Ag at 10V and 12V had little precipitate on the surfaces; this is because a carbon electrode was utilized, which tends to react with electrolyte at low voltages but does not do so at 14V. The films show that when the deposition voltage increased, the electrical resistivity decreased from 1.42 x 109 to 1.37 x 109 Ω.m and the thickness decreased from 125.02 to 123.025nm. This further led to an increase in conductivity from 7.04 x 108 to 7.29 x 108 S/m. It was discovered that the absorbance decreases as the electromagnetic radiation's wavelength grows and the deposition voltage rises. According to research done on the deposited material, its energy bandgap lies between 1.55 and 2.51 eV.&#x0D;

The Radio to GeV Afterglow of GRB 221009A

GRB 221009A (z = 0.151) is one of the closest known long γ-ray bursts (GRBs). Its extreme brightness across all electromagnetic wavelengths provides an unprecedented opportunity to study a member of this still-mysterious class of transients in exquisite detail. We present multiwavelength observations of this extraordinary event, spanning 15 orders of magnitude in photon energy from radio to γ-rays. We find that the data can be partially explained by a forward shock (FS) from a highly collimated relativistic jet interacting with a low-density, wind-like medium. Under this model, the jet’s beaming-corrected kinetic energy (E K ∼ 4 × 1050 erg) is typical for the GRB population. The radio and millimeter data provide strong limiting constraints on the FS model, but require the presence of an additional emission component. From equipartition arguments, we find that the radio emission is likely produced by a small amount of mass (≲6 × 10−7 M ⊙) moving relativistically (Γ ≳ 9) with a large kinetic energy (≳1049 erg). However, the temporal evolution of this component does not follow prescriptions for synchrotron radiation from a single power-law distribution of electrons (e.g., in a reverse shock or two-component jet), or a thermal-electron population, perhaps suggesting that one of the standard assumptions of afterglow theory is violated. GRB 221009A will likely remain detectable with radio telescopes for years to come, providing a valuable opportunity to track the full lifecycle of a powerful relativistic jet.

Effect of Waveguide Aperture and Distance on Microwave Treatment Performance in Rock Excavation.

Rock burst is a common hazard during tunnel excavation in high-stress and hard rock strata. Microwave-assisted breaking has a great potential application in hard rock tunnel excavation, reducing the possibility of rock burst, and how to reasonably make the application on the TBM cutterhead is one of the critical issues. The waveguide aperture and distance between the rock face and waveguide have serious effects on its performance. In this paper, based on the arrangement of the microwave waveguide of the TBM cutterhead and the actual excavation situation, considering the reflection of microwave energy by the metal cutterhead and the scattering state of electromagnetic waves at the rock surface irradiation, a 2D model of rock irradiated by microwaves is established. The effects of waveguide aperture and distance on microwave irradiation performance of rock are studied, considering three different waveguide types: convergent waveguide, rectangular waveguide, and horn waveguide. The results show that the maximum temperature is located on the rock irradiation surface, rather than inside the rock. The rock temperature decreases in a cosine pattern with irradiation distance, rather than in linearity, which is consistent with the characteristics of electromagnetic wave propagation. The interval of irradiation distance where the rock temperature local maximum value appears is 1/4 of the electromagnetic wavelength, corresponding to the crest and trough of the electromagnetic wave. The rock temperature at the wave trough distance is lower than that of the wave crest distance, but the high-temperature zone is wider. In the range of 50~200 mm waveguide apertures, the rock temperature and damage decrease with the increase in waveguide aperture when irradiated at the crest distance, while the valley distance is opposite. A convergent waveguide and short irradiation distance enhance the energy focusing performance, so the temperature rise characteristics and rock damage are more concentrated. A large-waveguide-aperture horn waveguide and long irradiation distance form a wide range of high-temperature zones and rock damages.

Shifting the plasmonic resonance to infrared region for AlP by inducing high S concentration: Indirect to direct band gap

In this work, structural, electronic, dielectric and thermoelectric properties of AlP with the presence of sulfur (S) impurities with various concentrations to form Al1P1−xSx with x = 0.083, 0.166 and 0.25 is studied using the first-principles density functional theory (DFT) based on the generalized gradient approximation (GGA). It was found that the presence of S leads to reducing the lattice parameter due to the strong electronegativity of S, and also leads to a direct band gap and increases the optical band gap, the conduction type of the doped systems are N-type degenerated semiconductor. Also, it is found that the increase of the doping concentration leads to an increase the electrical conductivity and thermal conductivity while it reduces the seebeck coefficient. Moreover, according to the linearity of the behavior obtained, it is found that when AlP is doped with 9.49% of S, the material can be in resonance with the electromagnetic wavelength of 10 μm that is necessary to detect sun radiations. This study shows that S doped AlP is an appropriate material for Thermoelectric Coupled NanoAntenna (TECNA's) applications.