Electromagnetic System Research Articles

Characterization on fibre kinking fracture of laminated composites under combined compression and shear at high loading rate

This paper presented a novel method to characterize the fracture toughness and cohesive law of laminated composites under combined compression and shear at high loading rate. Compact compression specimens with off-axis fibres which introduce the in-plane shear stresses were conducted on the uniaxial bidirectional electromagnetic Hopkinson bar system and the displacement field and strain field were recorded by the high-speed camera for the digital image correlation analysis and J-integral calculation. The results reveal that the in-plane shear stresses bring the increase of fracture toughness at crack initiation and propagation and advance the damage initiation of the specimens. The fracture surfaces indicate that the shear stresses cause the fibre bundles' shear failure during the formation of the kink band, accompanied by more energy dissipation with the increase of off-axis angle.

Direct electromagnetic information processing with planar diffractive neural network.

Diffractive neural network in electromagnetic wave-driven system has attracted great attention due to its ultrahigh parallel computing capability and energy efficiency. However, recent neural networks based on the diffractive framework still face the bottlenecks of misalignment and relatively large size limiting their further applications. Here, we propose a planar diffractive neural network (pla-NN) with a highly integrated and conformal architecture to achieve direct signal processing in the microwave frequency. On the basis of printed circuit fabrication process, the misalignment could be effectively circumvented while enabling flexible extension for multiple conformal and stacking designs. We first conduct validation on the fashion-MNIST dataset and experimentally build up a system using the proposed network architecture for direct recognition of different geometry structures in the electromagnetic space. We envision that the presented architecture, once combined with the advanced dynamic maneuvering techniques and flexible topology, would exhibit unlimited potentials in the areas of high-performance computing, wireless sensing, and flexible wearable electronics.

US & MR/CT Image Fusion with Markerless Skin Registration: A Proof of Concept.

This paper presents an innovative automatic fusion imaging system that combines 3D CT/MR images with real-time ultrasound acquisition. The system eliminates the need for external physical markers and complex training, making image fusion feasible for physicians with different experience levels. The integrated system involves a portable 3D camera for patient-specific surface acquisition, an electromagnetic tracking system, and US components. The fusion algorithm comprises two main parts: skin segmentation and rigid co-registration, both integrated into the US machine. The co-registration aligns the surface extracted from CT/MR images with the 3D surface acquired by the camera, facilitating rapid and effective fusion. Experimental tests in different settings, validate the system's accuracy, computational efficiency, noise robustness, and operator independence.

Shear‐driven flow of an ionic fluid in a narrow vertical channel under a Hall electric field

AbstractThis paper focuses on demonstrating the shear‐driven convective flow of an ionic optically thin fluid in a narrow channel formed by two vertical parallel plates subject to a Hall electric field. The Hall electric field induces Hall currents, amending the flow dynamics of the ionic fluid. The setup involves a stationary left wall and a right wall that either undergoes impulsive motion (IM) or accelerated motion (AM), which initiates the fluid flow. A unified closed‐form solution for flow‐regulating equations is derived by harnessing the Laplace transform (LT) approach. The upshots of cardinal parameters on the velocity components and temperature distributions, shear stresses, and rate of heat transfer (RHT) are elucidated via graphics for both IM and AM scenarios. The graphs reveal that an intensification in the Hall parameter notably boosts the velocity components in both IM and AM cases. The primary and secondary velocities are consistently higher for IM than AM. The magnitude of shear stresses at the moving wall is always greater for IM than AM. Additionally, the shear stresses at the moving wall are notably greater for IM than AM, and the RHT at the moving wall reduces as the radiation parameter amplifies. The significant findings of this research have potential applications in electromagnetic propulsion systems, like plasma or ion thrusters, commonly employed in propelling spacecraft.

Terminal-Matched Topological Photonic Substrate-Integrated Waveguides and Antennas for Microwave Systems.

In engineered photonic lattices, topological photonic (TP) modes present a promising avenue for designing waveguides with suppressed backscattering. However, the integration of the TP modes in electromagnetic systems has faced longstanding challenges. The primary obstacle is the insufficient development of high-efficiency coupling technologies between the TP modes and the conventional transmission modes. This dilemma leads to significant scattering at waveguide terminals when attempting to connect the TP waveguides with other waveguides. In this study, a topological photonic substrate-integrated waveguide (TPSIW) is proposed that can seamlessly integrate into traditional microstrip line systems. It successfully addresses the matching problem and demonstrates efficient coupling of both even and odd TP modes with the quasi-transverse electromagnetic modes of microstrip lines, resulting in minimal energy losses. In addition, topological leaky states are introduced through designed slots on the TPSIW top surface. These slots enable the creation of TP leaky-wave antennas with beam steering capabilities. A wireless link based on TPSIWs are further established that enables the transmission of distinct signals toward different directions. This work is an important step toward the integration of TP modes in microwave systems, unlocking the possibilities for the development of high-performance wireless devices.

An FPGA-Based signal acquisition system for 3D holographic azimuthal electromagnetic resistivity logging instruments

Abstract A signal acquisition system of a 3D holographic azimuthal electromagnetic resistivity logging instrument while drilling is designed based on the Field Programmable Gate Array (FPGA). The azimuth electromagnetic wave resistivity logging instrument is mainly composed of transmitting coils, receiving coils, and control circuits. The signal acquisition system mainly includes the receiving coil and corresponding signal acquisition and processing circuit. First of all, the whole structure of the electromagnetic wave resistivity instrument system while drilling is briefly introduced, and then each function module of the acquisition board is elaborated in detail, and the hardware realization of the signal acquisition module and the corresponding FPGA program design flow chart are given. The acquisition system makes full use of the structured design of the module and First input First output (FIFO) cache technology and can complete the functions of signal acquisition, data transmission, and control on the acquisition board in real-time by using Serial Communication Interface (SCI) information transmission interface. The simulation results show that the system can realize the function of data acquisition and processing well.

Validation of an electronic transformer electromagnetic nuisance online monitoring system in a true type platform

Validation of an electronic transformer electromagnetic nuisance online monitoring system in a true type platform

Research on control parameters of high-speed maglev train under stochastic track irregularities

During operational phases, maglev trains encounter track irregularities, presenting a formidable challenge to the integrity of their control systems owing to the inherently stochastic nature, a challenge accentuated in the context of high-speed maglev trains. This study aims to comprehensively examine control parameters within the context of stochastic excitation resulting from track irregularities. Through the development of a rigorous stochastic response analysis model utilizing the pseudo excitation method, the investigation delves into the dynamics of an EMS-type high-speed maglev train-rigid track system. Evaluation indices, derived from the power spectral density of the maglev train's response, are established to quantify both control stability and operational stability. Subsequently, based on these indices, a recommended range of PD control parameters is proposed, accounting for the requirements stipulated by the evaluation metrics. The study elucidates that variation in PD control parameters exert discernible effects on the system's stability, primarily altering the nature frequency and damping ratio. Specifically, control stability demonstrates a positive correlation with increasing PD control parameters, while operational stability exhibits a nuanced relationship—initially bolstered by escalating proportional coefficients but subsequently tempered, albeit gradually, with heightened derivative coefficients. The delineated range of values for PD control parameters is meticulously determined, considering pertinent physical parameters of the electromagnetic system, such as mass, static suspension current, and static suspension gap, alongside factors like the Sperling indicator and suspension gap variation.

Analyzing the Evolution of Needle and Ultrasound Probe Manipulation Skills of Interventional Radiology Trainees With Time and Experience.

To test the hypothesis that hand motion analysis can measure the progression of needle and ultrasound probe manipulation skills of interventional radiology trainees in central venous line placement. An expert cohort of 6 interventional radiologists and 4 anesthesiologists and a trainee cohort of 6 novice trainees (<50 central lines) and 5 experienced trainees (>50 central lines) performed simulated central venous access. Four novices and 1 experienced trainee repeated the task 1 year later. An electromagnetic motion tracking system tracked the needle hand and ultrasound probe. Path length, translational, and rotational movements were calculated separately for the needle hand and probe sensor. These metrics were used to calculate motion metrics based scores on a scale of 0 to 3 for each sensor. Nonparametric statistics were used, and the data are reported as median ± interquartile range. Comparing novice and experienced trainees, there was a significant difference in probe scores (experienced vs. novice: 1 ± 2 vs. 0 ± 0, P = 0.04) but not in needle-hand scores (1 ± 1.5 vs. 0 ± 1, P = 0.26). Trainees showed a significant increase in probe scores at the 1-year follow-up (baseline vs. follow-up: 0 ± 1 vs. 2.5 ± 1.8, P = 0.003), but no significant difference was observed in the needle manipulation metrics. Experts differed significantly from experienced trainees for all metrics for both sensors (P < 0.05), with the exception of the path length of the probe. Acquisition of improved dexterity of the probe may occur before improvement in the dexterity with the needle hand for interventional radiology trainees.

First-in-human use of a new robotic electromagnetic navigation bronchoscopic platform with integrated Tool-in-Lesion Tomosynthesis (TiLT) technology for peripheral pulmonary lesions: The FRONTIER study.

As the presentation of pulmonary nodules increases, the importance of a safe and accurate method of sampling peripheral pulmonary nodules is highlighted. First-generation robotic bronchoscopy has successfully assisted navigation and improved peripheral reach during bronchoscopy. Integrating tool-in-lesion tomosynthesis (TiLT) may further improve yield. We performed a first-in-human clinical trial of a new robotic electromagnetic navigation bronchoscopy system with integrated digital tomosynthesis technology (Galaxy System, Noah Medical). Patients with moderate-risk peripheral pulmonary nodules were enrolled in the study. Robotic bronchoscopy was performed using electromagnetic navigation with TiLT-assisted lesion guidance. Non-specific results were followed up until either a clear diagnosis was achieved or repeat radiology at 6 months demonstrated stability. Eighteen patients (19 nodules) were enrolled. The average lesion size was 20 mm, and the average distance from the pleura was 11.6 mm. The target was successfully reached in 100% of nodules, and the biopsy tool was visualized inside the target lesion in all cases. A confirmed specific diagnosis was achieved in 17 nodules, 13 of which were malignant. In one patient, radiological monitoring confirmed a true non-malignant result. This translates to a yield of 89.5% (strict) to 94.7% (intermediate). Complications included one pneumothorax requiring observation only and another requiring an overnight chest drain. There was one case of severe pneumonia following the procedure. In this first-in-human study, second-generation robotic bronchoscopy using electromagnetic navigation combined with integrated digital tomosynthesis was feasible with an acceptable safety profile and demonstrated a high diagnostic yield for small peripheral lung nodules.

Bridging papermaking and hydrogel production: Nanoparticle-loaded cellulosic hollow fibers with pitted walls as skeleton materials for multifunctional electromagnetic hydrogels

Electromagnetic hydrogels have attracted significant attention due to their vast potential in soft robotics, biomedical engineering, and energy harvesting. To facilitate future commercialization via large-scale industrial processes, we present a facile concept that utilizes the specialized knowledge of papermaking to fabricate hydrogels with multifunctional electromagnetic properties. The principles of papermaking wet end chemistry, which involves the handling of interactions among cellulosic fibers, fines, polymeric additives, and other components in aqueous systems, serves as a key foundation for this concept. Notably, based on these principles, the versatile use of chemical additives in combination with cellulosic materials enables the tailored design of various products. Our methodology exploits the unique hierarchically pitted and hollow tube-like structures of papermaking grade cellulosic fibers with discernible pits, enabling the incorporation of magnetite nanoparticles through lumen loading. By combining microscale softwood-derived cellulosic fibers with additives, we achieve dynamic covalent interactions that transform the cellulosic fiber slurry into an impressive hydrogel. The cellulosic fibers act as a skeleton, providing structural support within the hydrogel framework and facilitating the dispersion of nanoparticles. In accordance with our concept, the typical hydrogel exhibits combined attributes, including electrical conductivity, self-healing properties, pH responsiveness, and dynamic rheologic behavior. Our approach not only yields hydrogels with interesting properties but also aligns with the forefront of advanced cellulosic material applications. These materials hold the promise in remote strain sensing devices, electromagnetic navigation systems, contactless toys, and flexible electronic devices. The concept and findings of the current work may shed light on materials innovation based on traditional pulp and paper processes. Furthermore, the facile processes involved in hydrogel formation can serve as valuable tools for chemistry and materials education, providing easy demonstrations of principles for university students at different levels.

Design of an Electromagnetic Micro Mirror Driving System for LiDAR.

Electromagnetic micro mirrors are in great demand for light detection and ranging (LiDAR) applications due to their light weight and low power consumption. The driven frequency of electromagnetic micro mirrors is very important to their performance and consumption. An electromagnetic micro mirror system is proposed in this paper. The model of the system was composed of a micro mirror, an integrated piezoresistive (PR) sensor, and a driving circuit was developed. The twisting angle of the mirror edge was monitored by an integrated PR sensor, which provides frequency feedback signals, and the PR sensor has good sensitivity and linearity in testing, with a maximum of 24.45 mV/deg. Stable sinusoidal voltage excitation and frequency tracking was realized via a phase-locked loop (PLL) in the driving circuit, with a frequency error within 10 Hz. Compared with other high-cost solutions using PLL circuits, it has greater advantages in power consumption, cost, and occupied area. The mechanical and piezoresistive properties of micro mirrors were performed in ANSYS 19.2 software. The behavior-level models of devices, circuits, and systems were validated by MATLAB R2023a Simulink, which contributes to the research on the large-angle deflection and low-power-consumption drive of the electromagnetic micro mirror. The maximum optical scan angle reached 37.6° at 4 kHz in the behavior-level model of the micro mirror.

Mitigating Singularities in Control of Magnetic Capsule Endoscopes Using a Novel Nested Electromagnetic Coil System

Mitigating Singularities in Control of Magnetic Capsule Endoscopes Using a Novel Nested Electromagnetic Coil System

Non-linear impedance boundary condition from linear piecewise B-H curve applied to induction heating systems

Purpose This paper aims to apply the non-linear impedance boundary condition (IBC) for a linear piecewise B–H curve in frequency domain simulations to find the equivalent impedance of a simple induction heating system model. Design/methodology/approach An electromagnetic description of the inductor system is performed to substitute the effects of the induction load, for a mathematical condition, the so-called IBC. This is suitable to be used in electromagnetic systems involving high conductive materials at medium frequencies, as it occurs in an induction heating system. Findings A reduction of the computational cost of electromagnetic simulation through the application of the IBC. The model based on linear piecewise B–H curve simplifies the electromagnetic description, and it can facilitate the identification of the induction load characteristics from experimental measurements. Practical implications This work is performed to assess the feasibility of using the non-linear boundary impedance condition of materials with linear piecewise B–H curve to simulate in the frequency domain with a reduced computational cost compared to time domain simulations. Originality/value In this paper, the use of the non-linear boundary impedance condition to describe materials with B–H curve by segments, which can approximate any dependence without hysteresis, has been studied. The results are compared with computationally more expensive time domain simulations.

A performance enhanced P- and L-band double-ridged horn antenna

With the continuous development of electromagnetic detection systems, the working frequency of radar gradually expands towards the low-frequency band such as P- and L-band, and the low-frequency horn antenna has also attracted more and more attention. Given the problems of miniaturization, lightweight and ultra-wideband design of low-frequency horn antenna, this paper presents the optimal design for the feed balun, ridge curve, back-feed cavity and sidewall of the traditional horn antenna, and proposes a performance-enhanced double-ridged horn antenna covering 0.21-2.3 GHz. In the entire working band, the antenna has stable radiation patterns and good port-matching characteristics; its VSWR is less than 2 and the main lobes of patterns do not split or deteriorate. The proposed horn antenna can be used as a standard calibration or measurement antenna in antenna or material measurement systems.

A COMPREHENSIVE DESIGN AND SIMULATION OF QUADRUPOLE ELECTROMAGNETIC LINEAR SYSTEMS FOR PRECISE POSITIONING IN AEROSPACE

For linear motion applications, particularly in aerospace, this study outlines the creation of an essential Quadrupole Electromagnetic System (QES) as a substitute for a four-track electromagnetic launcher. The QES design is compared with a four-track system to address concerns regarding rail-armature contact sliding. In a QES, four coils provide a homogeneous electromagnetic field, resulting in a Lorentz force on the slider. The QES was designed using the three-dimensional modeling capabilities of the ANSYS software. The results of the magnetic properties show a high potential for scaling this model to various levels. Additionally, the QES power circuit was simulated using ANSYS Simplorer. The circuit uses silicon-controlled rectifiers (SCR) and a pulse-width modulation (PWM) pulse generator. A force of 4kN was achieved, and this paper presents the current and force plots in detail. The study includes finite element analysis, electromagnetic and current characteristics simulation, and monitoring of the skin and proximity effects. Performance is increased by optimizing the QES design parameters using Particle Swarm Optimization (PSO). The simulation results demonstrate the feasibility and scalability of the QES design.

Structural Design and Driving Experiment of an Electromagnetic Drive System for Microrobot

Abstract Controlling the exact positioning and direction of microrobots is a significant challenge in the prospect of microrobot actuation. To solve this problem, the current study created a system that combines solenoid and permanent magnets as an electromagnetic drive mechanism. This system uses a stepping motor to effectively manage the placement of the permanent magnet in the terminal area of solenoid, enabling precise control of its movement. Additionally, a programmable power source is used to adjust the microrobot’s orientation. Driving tests were conducted on a simulated hepatic vein, achieving speeds of up to 1.3mm/s. These results provide valuable references for optimizing future electromagnetic actuation systems.

Research on Construction of Test Environment for Assessment of RF-Induced Heating Effects of Implants

In magnetic resonance examination, the interaction between implants and the radio frequency (RF) fields induces heating in human tissue and may cause tissue damage. To assess the RF-induced heating of implants, three steps should be executed, including electromagnetic model construction, electromagnetic model validation, and virtual human body simulations. The crucial step of assessing RF-induced heating involves the construction of a test environment for electromagnetic model validation. In this study, a hardware environment, comprised of a RF generation system, electromagnetic field measurement system, and a robotic arm positioning system, was established. Furthermore, an automated control software environment was developed using a Python-based software development platform to enable the creation of a high-precision automated integrated test environment. The results indicate that the electric field generated in this test environment aligns well with the simulated electric field, making it suitable for assessing the RF-induced heating effects of implants.

Simultaneous electromagnetic field probing system with Y‐shaped separation detection structure

AbstractSimultaneous electromagnetic field probing system (SEMPS) has been popular in recent years. Herein, a simultaneous electromagnetic field probing system with Y‐shaped separation detection structure (SEMPS Y) is first proposed, in which the electric field probing region and the magnetic field probing region of the probe are separated by completely covering the shield along the loop and adding a pin‐shaped metal wire to capture the electric field, which are not the same as the classical dual probe structure. Combined with the non‐rotating asymmetric calibration method (NRACM), a 4‐port vector network analyser (VNA) and a highly symmetric grounded coplanar waveguide (GCPW) calibrator are used to solve the calibration matrix of the asymmetric SEMPS Y. The high symmetry GCPW calibrator is used to generate the standard electromagnetic field for calibration. The results of standing wave measurements show that the SEMPS Y can achieve ultrawideband electromagnetic field measurement of up to 20 GHz. Based on near‐field scanning measurements, SEMP Y can obtain results consistent with the calculation. In addition, when the probe is rotated 90° to invalidate the H‐field input, the decoupling curves of E‐field and H‐field are measured. Results show that the separation detection structure can effectively solve the cross‐coupling problem.

A Human-Scale Clinically Ready Electromagnetic Navigation System for Magnetically Responsive Biomaterials and Medical Devices.

Magnetic navigation systems are used to precisely manipulate magnetically responsive materials enabling the realization of new minimally invasive procedures using magnetic medical devices. Their widespread applicability has been constrained by high infrastructure demands and costs. The study reports on a portable electromagnetic navigation system, the Navion, which is capable of generating a large magnetic field over a large workspace. The system is easy to install in hospital operating rooms and transportable through health care facilities, aiding in the widespread adoption of magnetically responsive medical devices. First, the design and implementation approach for the system are introduced and its performance is characterized. Next, in vitro navigation of different microrobot structures is demonstrated using magnetic field gradients and rotating magnetic fields. Spherical permanent magnets, electroplated cylindrical microrobots, microparticle swarms, and magnetic composite bacteria-inspired helical structures are investigated. The navigation of magnetic catheters is also demonstrated in two challenging endovascular tasks: 1) an angiography procedure and 2) deep navigation within the circle of Willis. Catheter navigation is demonstrated in a porcine model in vivo to perform an angiography under magnetic guidance.