Uniform Electromagnetic Field Research Articles

Ultrasensitive SERS Detection of Five β-Blockers Achieved Using Chemometrics with a Two-Dimensional Substrate Formed by Large-Sized Ag@SiO2 Nanoparticles.

We report on a surface-enhanced Raman scattering (SERS) platform for the detection of five beta-blockers (β-blockers): atenolol, esmolol, labetalol, sotalol, and propranolol. Key to this platform was a two-dimensional substrate formed by self-assembling large Ag@SiO2 nanoparticles (Ag@SiO2 NPs) on a silicon wafer. The close arrangement of these large nanoparticles on the surface generated a strong and uniform electromagnetic field, which enhanced SERS signal intensity for the detection of small amounts of the target molecules. The intensities of characteristic peaks of the five β-blocker drugs increased linearly with the increase of their concentrations in the range of 10-5 to 10-8 mol/L. The detection limits were 10-10 mol/L for propranolol, 10-9 mol/L for atenolol, labetalol, and sotalol, and 10-8 mol/L for esmolol. Determination of these five β-blocker drugs added to human urine samples, using a portable Raman spectroscopy instrument, showed quantitative recovery (93-101%). Principal component analysis (PCA) and hierarchical cluster analysis (HCA) of SERS spectral data improved the differentiation among these five β-blockers. This study highlights the potential of the developed SERS platform for rapid, on-site detection of illicit drugs and for antidoping screening.

The Schwinger pair production method in the framework of non-commutative phase space coordinates and its applications

In noncommutative phase space (NCPS), we investigate the pair creation rate for the problem of scalar and spinorial particles emerging from a vacuum under the influence of uniform external electromagnetic fields using the Schwinger formal technique. It is demonstrated that under specific conditions, where the speed of light c approaches the Fermi velocity [Formula: see text] and [Formula: see text] (with [Formula: see text] representing the cyclotron frequency), the behavior of the Dirac oscillator problem in a uniform electromagnetic field within NCPS is akin to the monolayer graphene problem in NCPS. In addition, the production probability per unit volume per unit time is discussed, along with the limits of parameter deformations.

Design and optimization of a long-range surface plasmon resonance-based plasmonic SERS biosensor

In this paper, we designed and studied a novel type of hybrid chip based on long-range surface plasmon resonance (LRSPR) and surface-enhanced Raman scattering (SERS). The substrate has periodic arrangement gold nanoring cavity arrays structure, which can obtain a uniform and stable electromagnetic field distribution. In addition, due to the clever design of the long-range configuration (a “sandwich” structure with symmetric refractive index), the chip has a significant extended electromagnetic field enhancement ability. In numerous existing studies focusing on SERS performance, the consideration of plasmonic structure is limited to its shape and size, while neglecting the significance of spacer layer parameters. Thus, we use the Finite Difference Time Domain (FDTD) software to design and optimize the chip substrate configuration by investigating the impact of various parameters such as refractive index, spacer layer thickness, plasmonic structure's inner and outer radius, and period of array on the long-range effect. The presented geometrically-tunable long-range plasmonic chip provides a way to identify the governing factors for SERS and presents a design principle for optimizing SERS substrates.

High-permittivity ceramics enabled highly homogeneous zero-index metamaterials for high-directivity antennas and beyond

Zero-index metamaterials (ZIMs) can support uniform electromagnetic field distributions at any frequency, but their applications are hampered by the ZIM’s homogenization level—only 3 unit cells per free-space wavelength, which is fundamentally limited by the low-permittivity inclusions (εr ≈ 12) and background matrix (εr ≈ 1). Here, by filling high-permittivity SrTiO3 ceramic (εr ≈ 294) pillars in BaTiO3 (εr ≈ 25) background matrix, we demonstrate a highly homogeneous microwave ZIM with an over threefold increase in the homogenization level. Leveraging such a ZIM, we achieve not only an antenna, approaching the fundamental limit in the directivity with outstanding scalability, but also a concave lens with a focal length of as short as 1λ0. Our highly homogeneous ZIM has profound implications in ceramics, ZIM-based waveguides and cavities, free-space wavefront manipulation, and microwave quantum optics, and opens up enormous possibilities in wireless communications, remote sensing, global positioning satellites, etc.

Quadrupole Electromagnetic Linear Positioning System (QELPS):

In linear motion systems, including linear motors and actuators, precise and controlled linear motion is provided for various applications. However, they have several drawbacks: high costs, complexity, limited stroke length, high energy consumption, speed limitations, heat generation, noise and vibration, limited load capacity, environmental considerations, and integration challenges. High costs are especially significant for applications requiring high precision. The components' complexity and additional control electronics can increase maintenance and trouble-shooting requirements. Ensuring accurate and efficient operation necessitates regular maintenance. The limitation in stroke length, determined by the drive's size and guide length, can pose challenges for applications requiring long strokes. High energy consumption can be a concern, and speed limitations may be challenging. Managing heat generation is crucial to prevent component damage. Noise and vibration can be problematic, particularly in quiet applications. Integration challenges can arise when dealing with complex systems or automation processes. To overcome some of these drawbacks, an innovative coil configuration design for linear positioning system applications is proposed. The proposed design focuses on the Quadrupole Electromagnetic linear Positioning System (QELPS), comprising four coils generating a uniform electromagnetic field to produce a Lorentz force on the slider. The QELPS design is meticulously crafted using 3D modeling in ANSYS software, and the magnetic characteristics indicate the potential for scaling this model to different levels. The power circuit of the QELPS is simulated using ANSYS Simplorer and incorporates silicon-controlled rectifiers (SCR) and a pulse width modulation (PWM) pulse generator. The design achieves a force of 27.6 newtons with the paper presenting current and force plots in comprehensive detail. Furthermore, an interactive design algorithm is introduced, facilitating the customization of this model for various linear track dimensions. This research aims to advance linear drive technology and enhance linear motion applications by developing this new coil configuration design and harnessing the Quadrupole Electromagnetic System.

Improved field uniformity in EMC chamber for 6G communication

<span>This paper shows electromagnetic field uniformity in an electromagnetic compatibility (EMC) chamber that is used as a test facility for measuring electromagnetic interference and radiated immunity of 6G communication systems. While not defined yet, 6G radio frequency will work in the wavelength ranges above 95 GHz. With this reason, this paper designed a schroeder-type quadratic residue diffuser for 95 GHz to generate a uniform electromagnetic field in the EMC chamber and studied the field uniformity characteristics in it. To analyze the distribution of electromagnetic fields inside the EMC chamber, finite-difference time-domain (FDTD) numerical analysis method is used. The simulation results show that the EMC chamber with this diffuser satisfies the requirements of international standards and has improved the field uniformity in the chamber.</span>

Second-harmonic generation in fluctuating Ising superconductors

In a two-dimensional noncentrosymmetric transition metal dichalcogenide Ising superconductor in the fluctuating regime under the action of a uniform external electromagnetic field, a second-harmonic generation (SHG) effect takes place. There emerge two contributions to this effect, one conventional, which is due to the electron gas in its normal state, and the other one is of the Aslamazov–Larkin nature. Namely, it originates from the presence of fluctuating Cooper pairs in the system when the temperature approaches the temperature of the superconducting transition in the sample from above. Employing a usual approach to Ising superconductors, we lift the valley degeneracy by application of a weak out-of-plane external magnetic field, which produces a Zeeman effect. In calculations, we use the Boltzmann equations approach for the electron gas in the normal state, and the time-dependent Ginzburg–Landau equations for the fluctuating Cooper pairs, and show the emergence of SHG electric current characterized by a temperature-dependent broadening and a redshift.

ПІДСУМКИ ТА ПЕРСПЕКТИВИ ПІДВИЩЕННЯ ХАРЧОВОЇ ЦІННОСТІ ПАЙКІВ ДЛЯ ВІЙСЬКОВОСЛУЖБОВЦІВ ПІДРОЗДІЛІВ, ЩО ВЕДУТЬ АВТОНОМНІ БОЙОВІ ДІЇ

The article considers the results and prospects of increasing the nutritional value of rations for servicemen of units conducting autonomous combat operations. As an example, the intelligence unit of the Ground Forces of the Armed Forces of Ukraine (SV AFU) is considered. An analysis of improving the quality of rations due to the introduction of modern production technologies, such as microwave (ultra-high-frequency) processing and sublimation, was carried out. The main advantages of microwave processing are determined: the preservation of more nutrients, high processing speed, more uniform heating, economic energy consumption, a wide range of applications. The main advantages of sublimation have been determined: the preservation of the high quality of the product, natural aroma, taste, chemical structure, increase in shelf life, the stability of the process, which allows to ensure the same quality, and the quantity of the product in each batch, the maximum possible reduction in the mass of the finished product. The obtained research results indicate that the selectivity of microwave heating of microorganisms in a non-resonant chamber allows to reduce the exposure time of the product when it is processed in a uniform electromagnetic field by 4-5 times. It is noted that rational nutrition is an important factor in preserving and maintaining the health of military personnel, as well as maintaining their high combat capability. In order to increase the nutritional standards of servicemen of the units of the Armed Forces of the Armed Forces of Ukraine and provide them with high-quality food products enriched with vitamins and minerals, a commodity analysis of dry food rations used in Italy, Spain, Lithuania and Poland was carried out. It is proposed to improve the set of food products to the complex of combat equipment of a soldier, to which are attached: tablets for water disinfection (based on 1 liter per meal); a set of dry products with a high iodine content (for example, "kelp"); a set of dry products, dry products with a high protein composition (for example, "dried banana"). Keywords: ration, quality, nutritional value, microwave processing, sublimation, dry products.

Tuning bulk topological magnon properties with light-induced magnons

Although theoretical modeling and inelastic neutron scattering measurements have indicated the presence of topological magnon bands in multiple quantum magnets, experiments remain unable to detect a signal of the magnon thermal Hall effect in the quantum magnets, which is a consequence of magnons condensation at the bottom of the bands following Bose-Einstein statistics as well as the concentration of Berry curvature at the higher energies. In recent work, Malz et al. [Nat. Commun. 10, 3937 (2019)] have shown that topological magnons in edge states in a finite sample can be amplified using tailored electromagnetic fields. We extend their approach by showing that a uniform electromagnetic field can selectively amplify magnons with finite Berry curvature by breaking the inversion symmetry of a lattice. Using this approach, we demonstrate the generation of bulk topological magnons in a Heisenberg ferromagnet on the breathing kagome lattice and the consequent amplification of the thermal Hall effect.

Photogalvanic transport in fluctuating Ising superconductors

In a two-dimensional noncentrosymmetric Ising superconductor in the fluctuating regime under the action of a uniform external electromagnetic field there emerge two contributions to the photogalvanic effect due to the trigonal warping of the valleys. The first contribution stems from the current of the electron gas in its normal state, while the second contribution is of Aslamazov-Larkin nature: it originates from the presence of fluctuating Cooper pairs when the ambient temperature approaches (from above) the temperature of superconducting transition in the sample. The way to lift the valley degeneracy is the application of a weak out-of-plane external magnetic field producing a Zeeman effect. The Boltzmann equations approach for the electron gas in the normal state and the time-dependent Ginzburg-Landau equations for the fluctuating Cooper pairs allow for the study of the photogalvanic current in two-dimensional transition metal dichalcogenide Ising superconductors.

Cooling System Design and Thermal Analysis of Modular Stator Hybrid Excitation Synchronous Motor

Hybrid excitation synchronous motor has the advantages of uniform and adjustable electromagnetic field, wide speed range and high power density. It has broad application prospects in new energy electric vehicles, wind power generation and other fields. This paper introduces the basic structure of hybrid excitation motor with modular stator, and analyzes the operation principle of hybrid excitation motor. The cooling structure of the water-cooled plate is designed, and the effects of the thickness of the water-cooled plate and the number of water channels in the water-cooled plate on the heat dissipation capacity of the water-cooled plate are analyzed by theoretical and computational fluid dynamics methods. The effects of different water cooling plate structures on water velocity, pressure drop, water pump power consumption and heat dissipation capacity were compared and analyzed. The influence of different inlet flow velocity on the maximum temperature rise of each part of the motor is analyzed, and the temperature of each part of the motor under the optimal water flow is analyzed. The influence of the traditional spiral water jacket cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of the motor components is compared and analyzed. The results show that the water-cooled plate cooling structure is more suitable for the modular stator motor studied in this paper. Based on the water-cooled plate cooling structure, the air-water composite cooling structure is designed, and the effects of the air-water composite cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of each component of the motor are compared and analyzed. The results show that the maximum temperature rise of each component of the motor is reduced under the air-water composite cooling structure.

FDTD Analysis on WPT Efficiency Between Circuit-Shape Leaky Waveguide and 𝝀/2 Dipole Antenna for Snow Melting Application

The wireless transfer characteristics between a circuit-shape leaky waveguide and a /2 dipole antenna were analyzed with scattering parameters obtained with the FDTD method. The circuit-shaped leaky waveguide was composed of two pairs of straight slotted waveguides and two semicircular waveguides. The circuit-shape leaky waveguide was designed to achieve uniform electromagnetic field distribution with a source for snow melting with microwave radiations by microwave heating. The electromagnetic field of the circuit-shape leaky waveguide was firstly simulated with the FDTD method. Although the electromagnetic distribution exhibited the point symmetry with an off-set feeding point and a slot spacing 𝝀𝒈, it was nearly uniform. The wireless transfer efficiency and the maximum transfer efficiency for four locations at 2.45 GHz revealed that the farthest location from the feeding point had the largest WPT efficiency among four locations. This ensures the circuit-shape leaky waveguide’s uniqueness. The circuit-shape leaky waveguide has favorable characteristics to provide WPT energy at any location above it.

Knowledge Analysis of Charged Particle Motion in Uniform Electromagnetic Field Based on Maxwell Equation

Abstract We study the motion states of charged particles in a homogeneous electromagnetic field based on the Maxwell equations. The authors propose the charged particle properties analysis based on the Maxwell equation and electromagnetic field, first explain the Maxwell equation and electromagnetic field properties analysis, and then analyze the charged particles in the composite field (electric and magnetic field coexistence). List the important knowledge points about the motion of charged particles in an electric field, and determine the center of the circle where the charged particles move in a circular motion, simulate the motion of charged particles in a uniform orthogonal electromagnetic field, if at, the trajectory of the charged particle is a short-amplitude cycloid, if, the trajectory of the charged particle is a long cycloid, if. The realization of simulation is mainly based on theory to obtain phenomena, although it has extensive practical significance for confirmatory experiments, when inspiring and guiding students to carry out inquiry learning, physics teachers should still organically combine simulation experiments with traditional experimental teaching, teacher explanations, and student experiments in teaching design and teaching implementation, in order to cultivate students' independent inquiry ability and experimental innovation ability.

On the world sheet of anyon in the external electromagnetic field

We study the issue of description of spinning particle dynamics by means of recently proposed world sheet concept. A model of irreducible spinning particle in the 3d Minkowski space with two gauge symmetries is considered. The classical trajectories of free particle lie on a circular cylinder with a time-like axis. The direction of cylinder axis is determined by the particle momentum, and its position in space-time depends on the value of total angular momentum. The radius of cylinder is determined by the representation. The model admits inclusion of consistent interactions with a general (not necessarily uniform) electromagnetic field. The classical trajectories of the particle lie on the cylindrical hypersurface in space time, whose position is determined by the initial values of the momentum and total angular momentum. All the world paths that lie on one and the same representative in the set of hypersurfaces are connected by gauge transformations. The general construction is illustrated by the example of unform electric field. In this case, the particle paths are shown to be general pseudotoroidal lines.

Using Overlapped Resonators in Wireless Power Transfer for Uniform Electromagnetic Field and Removing Blank Spots in Free Moving Applications

We propose an induction link based on overlapping arrays to eliminate blank spots on the electromagnetic field for moving object applications. We use two arrays of four aligned coils that have a 50% overlap between the two plates. This mechanism compensates for the internal coil power drop at positions in the boundaries between two adjacent external coils. We showed that if these plates are excited, a uniform electromagnetic field is created in the movement direction of the moving object. This uniform electromagnetic field distribution will result in a constant receiving power at all points in the path of the moving internal coil with the same power consumption of one coil excitation. Power delivery to the moving object tolerance reaches 10% at most, while, in non-overlapped scenarios, it is approximately 50%. In addition, according to the theoretical calculations, printed circuit coils (PCB) for the array are designed for maximum efficiency. We found that the change in distance and dimensions of the receiver coil has a linear effect on power and efficiency. Moreover, a Specific Absorption Rate (SAR) simulation was performed for biocompatibility. In this paper, we investigate and record a 68% electrical power efficiency for the fabricated system. The array consists of eight transmitters coils of the same size and shape and a receiver coil at a distance of 4 cm. Furthermore, the fabricated coil has shown improved efficiency compared to similar studies in the literature and introduces a promising structure for bio-test applications.

Effect of the Magnetospheric Plasma Interaction and Solar Illumination on Ion Sputtering of Europa’s Surface Ice

AbstractFor the entire ion energy range observed at Europa, we calculate spatially resolved maps of the surface sputtering rates of H2O, O2, and H2 from impacts by magnetospheric ions. We use the perturbed electromagnetic fields from a hybrid model of Europa’s plasma interaction, along with a particle‐tracing tool, to calculate the trajectories of magnetospheric ions impinging onto the surface and their resultant sputtering yields. We examine how the distribution of the sputtering rates depends on the electromagnetic field perturbations, the angle between the solar radiation and the corotating plasma flow, and the thickness of the oxygen‐bearing layer within Europa’s surface. Our major findings are: (a) Magnetic field‐line draping partially diverts the impinging ions around Europa, reducing the sputtering rates on the upstream hemisphere, but allowing for substantial sputtering from the downstream hemisphere. In contrast, zero sputtering occurs in much of the downstream hemisphere with uniform electromagnetic fields. (b) If the oxygen‐bearing surface layer is thin compared to the penetration depth of magnetospheric ions, thermal ions dominate the O2 sputtering rates, and the region of strongest sputtering is persistently located near the upstream apex. However, if the oxygen‐bearing layer is thick compared to the penetration depth, energetic ions sputter the most O2, and the location of maximum sputtering follows the sub‐solar point as Europa orbits Jupiter. (c) The global production rate of O2 from Europa’s surface varies by a factor of 3 depending upon the Moon’s orbital position, with the maximum particle release occurring when Europa’s Sun‐lit and upstream hemispheres coincide.

The periodic solutions of a symmetric charged gyrostat for a slightly relocated center of mass

This paper aims to investigate the rotatory dynamical motion of a charged symmetric gyrostat when its center of mass is slightly displaced from the axis of dynamic symmetry as a novel case. A uniform electromagnetic field, due to the presence of point charge located on the axis of symmetry, and a gyrostatic moment are acted on the gyrostatic motion. Equations of motion are derived and solved analytically using the small parameter method of Poincaré for irrational frequencies’ case of the examined motion of the gyrostat. The approximate formulas of the rotating Euler’s angles of the gyrostat are obtained. The time histories of the achieved results and the Euler’s ones are graphed to display the excellent influence of the chosen parameters of the gyrostat on the motion. Moreover, the phase plane diagrams of these results are graphed also to reveal the stability of the gyrostatic motion at any time. The attained results can be used to improve the dynamical behavior of several engineering applications, particularly those that employ the gyroscopic theory such as satellites, submarines, compasses, and automatic pilots on aircraft and ships.

Generation of long homogeneous plasma channels with high power long-wave IR pulsed Bessel beams.

Long-wave multi-joule ultrashort laser pulses are predicted to confine highly uniform electromagnetic energy and field intensities while sustaining high density uniform plasmas within nonlinear Bessel zones under extreme driving conditions in contrast to near-IR sources. This opens up novel applications in laser wakefield generation, radiofrequency/microwave guiding, and lightning control.

Dynamics of dipole in a stationary non-homogeneous electromagnetic field

The non-relativistic equations of motion for a dipole in a stationary non-homogeneous electromagnetic field are derived and analysed. It is shown that they are Hamiltonian with respect to a certain degenerated Poisson structure. Described by them dynamics is complex because the motion of the centre of mass of the dipole is coupled with its rotational motion. The problem of the existence of linear in momenta first integrals which can be useful for the separation of rotational motion is discussed. The presence of such first integral appears to be related with a linear symmetry of electric and magnetic fields. Also results of search of quadratic in momenta first integrals for uniform and stationary electromagnetic fields are reported. Deriving equations of motion of a dipole in arbitrary stationary electromagnetic fields and analysis of described by them dynamics is important for the construction of electromagnetic traps for polar particles.

Measuring the Magnetic Polarizability Tensor Using an Axial Multi-Coil Geometry

The Magnetic Polarizability Tensor (MPT) is a representative property of an electrically conducting or magnetic object that includes information about the object’s characteristics such as, shape, size and material. The MPT is especially relevant to metal detection (MD) and can be used to improve MD performance by helping to distinguish between objects. This paper describes an instrument intended to measure the MPT of objects such as anti-personnel landmines and metallic clutter, up to 130 mm in diameter. The instrument uses a novel multi-coil geometry to generate a uniform electromagnetic field over the volume containing the test object to accurately determine the MPT. Performance tests of the system shows peak variance in the MPT is approximately 15 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . Typical experimental repeatability is better than one percent for tests involving copper disks. Additionally, simulated data as well as previously published simulated and experimental data are used as a validation method of the experimental results. Good agreement between these and the measured MPTs of example targets are seen, proving the system’s capability of characterizing metallic objects.