Electromagnetic Stability Research Articles

Multifunctional metallized particleboard for enhanced electromagnetic interference shielding and mechanical thermal stability

Multifunctional metallized particleboard for enhanced electromagnetic interference shielding and mechanical thermal stability

A mechanics and electromagnetic scaling law for highly stretchable radio frequency electronics

Many classes of flexible and stretchable bio-integrated electronic systems rely on mechanically sensitive electromagnetic components, such as various forms of antennas for wireless communication and for harvesting energy through coupling with external power sources. This efficient wireless functionality can be important for body area network technologies and can enable operation without the weight and bulky size of batteries for power supply. Recently, antenna designs have received increased attention because their mechanical and electromagnetic properties significantly influence the wireless performance of bio-integrated electronics, particularly under excessive mechanical loads. These mechanical factors are critical for skin-integrated electronics during human motion, as complex skin deformations can damage the conductive traces of antennas, such as those used for near-field communication (NFC), leading to yield or fracture and affecting their electromagnetic stability. Serpentine interconnects have been proposed as a geometric alternative to in-plane circular or rectangular spiral antenna designs to improve the elastic stretchability of the metallic traces in NFC antennas and prevent mechanical fractures. Despite the use of serpentine interconnects within the physiologically relevant strain range for skin (<20 %), the electromagnetic stability of the antennas decreases. This instability, reflected by shifts in resonance frequency and scattering parameters due to inductance changes, reduces the antennas' wireless power transfer efficiency and readout range. Therefore, maintaining the electromagnetic stability of antennas, specifically NFC antennas, under various mechanical deformations has become a critical challenge in practical wireless skin-integrated applications, such as sensing and physiological monitoring. Here, we establish a new mechanics and electromagnetic scaling law that quantifies the inductance changes under strain in a rectangular-loop serpentine structure typically used for NFC wireless communication in stretchable electronics. We present a systematic analysis of the antenna's geometric parameters, material properties of the antenna and substrate, and the applied strain on the inductance change. Our findings demonstrate that the relative change of inductance is solely influenced by the serpentine structure's width-radius ratio, arc angle, aspect ratio of the NFC antennas, and the applied strain. Additionally, under physiological strain conditions for the skin, the relative change of inductance can be minimized to preserve the NFC antenna's performance and prevent mechanical fracture and electromagnetic stability loss.

Eco-Friendly Material Handling Systems for Industries Using Maglev Technology

Magnetic Levitation (Maglev) technology has transformed material handling by offering an efficient, contactless method for object transport. This innovation relies on electromagnetic repulsion and stabilization, eliminating the need for traditional mechanical systems. Through powerful magnetic fields and superconducting materials, Maglev systems effortlessly suspend and propel objects with minimal friction and energy consumption. This review delves into Maglev's advancements and applications in material handling, exploring fundamental principles like electromagnetic repulsion and stability control. It emphasizes benefits such as reduced maintenance, increased throughput, and enhanced safety. The article provides insights into Maglev's applications, spanning warehouse automation, assembly line transportation, and high-speed logistics. It highlights how Maglev systems elevate operational efficiency, optimize space, and deliver precise control over object movement, resulting in faster and more reliable material handling processes.

A High-Voltage Cathode Material with Ultralong Cycle Performance for Sodium-Ion Batteries.

Vanadium-based polyanionic materials are promising electrode materials for sodium-ion batteries (SIBs) due to their outstanding advantages such as high voltage, acceptable specific capacity, excellent structural reversibility, good thermal stability, etc. Polyanionic compounds, moreover, can exhibit excellent multiplicity performance as well as good cycling stability after well-designed carbon covering and bulk-phase doping and thus have attracted the attention of multiple researchers in recent years. In this paper, after the modification of carbon capping and bulk-phase nitrogen doping, compared to pristine Na3V2(PO4)3, the well optimized Na3V(PO3)3N/C possesses improved electromagnetic induction strength and structural stability, therefore exhibits exceptional cycling capability of 96.11% after 500 cycles at 2C (1C=80mAg-1) with an elevated voltage platform of 4V (vs Na+/Na). Meanwhile, the designed Na3V(PO3)3N/C possesses an exceptionally low volume change of ≈0.12% during cycling, demonstrating its quasi-zero strain property, ensuring an impressive capacity retention of 70.26% after 10,000 cycles at 2C. This work provides a facial and cost-effective synthesis method to obtain stable vanadium-based phosphate materials and highlights the enhanced electrochemical properties through the strategy of carbon rapping and bulk-phase nitrogen doping.

Multi-interfaced Ni/C@RGO/PTFE composites for electromagnetic protection applications with high environmental stability and durability

To efficiently address the growing electromagnetic pollution problem, it is urgently required to research high-performance electromagnetic materials that can effectively absorb or shield electromagnetic waves. In addition, the stability and durability of electromagnetic materials in complex practical environments is also an issue that needs to be noticed. Therefore, the starting point for our problem-solving is how to endow magnetic/dielectric multi-interfaced composite materials with excellent electromagnetic protection capability and environmental stability. In this study, magnetic/dielectric multi-interfaced Ni/carbon@reduced graphene oxide/polytetrafluoroethylene (Ni/C@RGO/PTFE) composites were developed to utilize as excellent EWA (electromagnetic wave absorption) and EMI (electromagnetic interference) shielding materials. Due to their diverse heterogeneous interfaces, rich conductive networks, and multiple loss mechanisms, the Ni/C@RGO/PTFE composite exhibits an optimal reflection loss of −61.48 dB and an effective absorption bandwidth of 7.20 GHz, with a filler loading of 5 wt%. Furthermore, Ni/C@RGO/PTFE composite films have an optimal absorption effectiveness value of 9.50 dB and an absorption coefficient of 0.49. Moreover, Ni/C@RGO/PTFE can hold high EWA performance in various corrosive media and maintain more than 90% of EMI shielding effectiveness, which can be attributed to the carbon coating and PTFE matrix acting as dual protective barriers for the susceptible metal Ni, thus obviously improving the stability and durability of composites. Overall, this work presents an effective strategy for the growth of high-performance EWA and EMI shielding materials with outstanding environmental stability and durability, which have wide application prospects in the future.

Biphasic GaIn Alloy Constructed Stable Percolation Network in Polymer Composites over Ultrabroad Temperature Region.

Flexible and adaptable polymer composites with high-performance reliability over wide temperature range are imperative for various applications. However, the distinct filler-matrix thermomechanical behaviors often cause severe structure damage and performance degradation upon large thermal shock. To address this issue, a general strategy is proposed to construct leakage-free, self-adaptive, stable percolation networks in polymer composites over wide temperature (77-473 K) with biphasic Ga35In65 alloy. The in situ micro-CT technology, for the first time, reveals the conformable phase transitions of Ga35In65 alloys in the polymer matrix that help repair the disruptive conductive networks over large temperature variations. The cryo-expanded Ga compensates the disruptive carbon networks at low temperatures, and flowable Ga and melted In at high temperatures conformably fill and repair the deboned interfaces and yielded crevices. As a proof-of-concept, this temperature-resistant composite demonstrates superb electrical conductivity and electromagnetic interference shielding properties and stability even after a large temperature shock (ΔT = 396 K). Furthermore, the superiority of the construction of temperature self-adaptive networks within the composite enables them for additive manufacturing of application-oriented components. This work offers helpful inspiration for developing high-performance polymer composites for extreme-temperature applications.

Study on the Applicability of Flexible Graphite Grounding Body and Grounding Module for 500kV Transmission Line in High Altitude Area

Sichuan-Tibet Railway Changdu-Linzhi section construction power supply project (Phase II) by Tibet Power Grid Co. 4900m), the mountain is treacherous, the foundation excavation is difficult (mostly rock foundation). Among them, 3 times across 35kV lines, 1 time across 220kV lines, 1 time across the Nujiang River, across the construction is more difficult. At present, China often use galvanized steel, galvanized copper and other traditional grounding materials, due to corrosion phenomenon caused by the increase in grounding resistance, affecting the frequency current, lightning current dispersion, but also cause local stride voltage and contact voltage does not meet the requirements of the regulations, generally in 8 years need to be replaced, which greatly increases the construction cost. In order to ensure the safe operation of power equipment and the safety of staff operation, stable and highly reliable grounding materials are needed. In recent years, flexible graphite material is widely used in grounding engineering, which has good electromagnetic characteristics and strong chemical stability, not easy to be eroded by the environment, and can operate in the grounding of power equipment in a long-term and stable manner. In this paper, the soil geological structure and typical line tower grounding resistance in Tibetan area are tested and analyzed, and the flexible graphite grounding material is applied to the grounding transformation of line tower in combination with local problems in Tibet, which can reduce the burial depth of grounding electrode, and compared with the solution of using traditional grounding material, it can reduce the cost and improve the project progress, and help the construction unit and construction unit to control the budget and construction period.

Co-simulation of real-time electromagnetic transient and transient stability simulations using dynamic phasor T-Line model

This paper presents techniques to interface a Transient Stability Analysis (TSA) based model to an ElectroMagnetic Transient (EMT) based model running on a Real Time Digital Simulator. Practical challenges of implementing such an interface are discussed. The proposed TSA model can be simulated using a substantially larger time-step compared to the EMT model. The interface between the EMT model and the TSA model is implemented using a transmission line modeled using Dynamic Phasors (DP). Time-step delay is the primary cause of numerical instability in co-simulations. In this work, a traveling wave model of a transmission line is used to decouple the EMT and TSA networks. The interface requires that the propagation delay of the interfaced transmission lines be greater than the EMT time-step even though the TSA is simulated using a much larger time-step than the EMT model. The proposed technique is validated using the IEEE 39 bus system and a power system with 500 buses.

η -pairing on square and triangular lattices

The $\ensuremath{\eta}$-pairing is a type of Cooper pairing state in which the phase of the superconducting order parameter is aligned in a staggered manner, in contrast to the usual BCS superconductors with a spatially uniform phase. In this study, we search for a characteristic $\ensuremath{\eta}$-pairing state in a triangular lattice where a simple staggered alignment of the phase is not possible. As an example, we consider the attractive Hubbard model on both the square and triangular lattices under a strong external Zeeman field. Using the mean-field approximation, we have identified several $\ensuremath{\eta}$-pairing states. Additionally, we have examined the electromagnetic stability of the pairing state by calculating the Meissner kernel. Odd-frequency pairing plays a crucial role in achieving a diamagnetic response if the electrons experience a staggered superconducting phase during the propagation of current.

APC Nb3Sn superconductors based on internal oxidation of Nb–Ta–Hf alloys

In the last few years, a new type of Nb3Sn superconducting composite, containing a high density of artificial pinning centers (APC) generated via an internal oxidation approach, has demonstrated a significantly superior performance relative to present, state-of-the-art commercial Nb3Sn conductors. This was achieved via the internal oxidation of Nb-4at.%Ta-1at.%Zr alloy. On the other hand, our recent studies have shown that internal oxidation of Nb–Ta–Hf alloys can also lead to dramatic improvements in Nb3Sn performance. In this work we follow up on this latter approach, fabricating a 61-stack APC wire based on the internal oxidation of Nb-4at.%Ta-1at.%Hf alloy, and compare its critical current density (J c) and irreversibility field with APC wires made using Nb-4at.%Ta-1at.%Zr. A second goal of this work was to improve the filamentary design of APC wires in order to improve their wire quality and electromagnetic stability. Our new modifications have led to significantly improved residual resistivity ratio and stability in the conductors, while still keeping non-Cu J c at or above the conductor J c specification required by the proposed Future Circular Collider. Further improvement via optimization of the wire recipe and design is ongoing. Finally, additional work needed to make APC conductors ready for applications in magnets is discussed.

Electromagnetic compatibility analysis of thermal energy recovery power system driven by new energy vehicles

In order to ensure the stability of battery management power system, improve the reliability of on-board electronic products, and ensure the stability of thermal energy recovery power system, the author proposes an electromagnetic compatibility optimization scheme based on wiring harness, power module, and PCB noise, taking the battery management system of vehicle electronic components as an example, the role of electromagnetic compatibility on products is described, the hardware circuit is analyzed and designed by electromagnetic compatibility design theory to ensure the reliability of vehicle components. The electromagnetic stability of the power battery is guaranteed through the electromagnetic compatibility optimization analysis of the battery management system, so as to achieve more stable battery management. The experimental results show that each module of the battery management system works stably, and the disturbance degree test shows that the resonant noise of the battery management system disappears, and there is no obvious narrowband electromagnetic disturbance, and the overall value is below the limit of 20 dB. In conclusion the electomagnetic compatibility optimization scheme can effectively ensure the stability of the battery management power system, and indirectly ensure the stability of the heat recovery power system.

Characteristics Analysis of an Electromagnetic Actuator for Magnetic Levitation Transportation

In this article, an electromagnetic actuator is proposed to improve the driving performance of magnetic levitation transportation applied to ultra-clean manufacturing. The electromagnetic actuator mainly includes the stator with the Halbach array and the mover with a symmetrical structure. First, the actuator principle and structure are illustrated. Afterward, in order to select a suitable secondary structure and analyze the characteristics of the actuator, the electromagnetic characteristics of actuators with different secondary structures are analyzed by the finite element method (FEM). Analysis results show that the actuator adopting the secondary structure with a Halbach array will increase the electromagnetic force and working stability. The secondary with the three-section Halbach array is selected for the electromagnetic actuator. Then, the influence of secondary permanent magnet (PM) thickness on the electromagnetic force is analyzed by FEM. The results indicate that the increase in PM thickness will lead to increased electromagnetic force and decreased utilization ratio of PM. Finally, a prototype of an electromagnetic actuator is built, and experiments are implemented. The correctness of the theoretical analysis and the effectiveness of the electromagnetic actuator are verified by experimental results.

Ultra-broadband origami absorber with large angle stability in the THz region

A three-dimensional origami-structured absorber based on V O 2 is designed. The unit structures of the origami absorber are folded from both sides to the middle, and a cavity is formed. After simulation, it is found that this absorber possesses insensitivity to polarized electromagnetic waves and stability at large incident angles. In addition, the origami absorber exhibits good absorption performance at low frequencies. An absorption band with absorptivity over 0.9 at 0.61–6.5 THz can be formed in TE mode. The coverage of the absorption band exceeds 10 octaves, and the relative bandwidth is 165.7%. In TM mode, the absorption band is located at 0.68–6.5 THz, which exceeds 9.5 octaves, and the relative bandwidth is 162.1%. We demonstrate the absorption mechanism by analyzing the electric field, surface current, and magnetic field distribution.

INVESTIGATION OF THE TEMPERATURE DEPENDENCE OF TFBG WITH TILT ANGLES OF 20 AND 40

Due to advantages such as electromagnetic stability, durability, and high sensitivity, fiber Bragg gratings have found application as sensors of physical quantities. A special place in the line of such devices is occupied by Bragg gratings with tilted strokes (Tilted fiber Bragg grating- TFBG). At the moment, TFBGs are used to estimate the velocity of two-phase flows, to create a torsion sensor, as temperature and deformation sensors, etc. This article examines the possibility of implementing a temperature sensor based on TFBG with an angle of inclination of 2° and 4° inscribed in a single-mode optical fiber. For this purpose, experimental studies of the dependence of the wavelength of the Bragg resonance on temperature have been carried out. The grating period is 540 nm and the length is 10 mm. The temperature ranged from 30 °C to 85 °C in increments of 5 degrees. The results of the experiment are to find a linear dependence of the minimum wavelength of the Bragg resonance λB on the change in ambient temperature.

Development of a method for calculating the transmission‐line constants of cables installed in a rectangular tunnel

AbstractAccurately calculating the transmission‐line constants of underground cables is important for various types of power system simulations such as electromagnetic transient, power flow, and transient stability simulations. The transmission line constants of cables installed in a tunnel must be calculated taking the skin and proximity effects into account, since the cables are spaced closely to each other and also to a wall face of the tunnel. However, the conventional method, which is capable of considering the skin and proximity effects, has been restricted to circular cross‐section conductors such as cables and a circular tunnel. Therefore, the method cannot handle a tunnel with a rectangular cross section. In this paper, a method for calculating the transmission‐line constants of a conductor system in which both circular and rectangular cross‐section conductors present in the same space is proposed. Then, the walls of a rectangular tunnel are represented by eight rectangular conductors, and cables represented by circular conductors are placed inside the eight rectangular conductors. In this paper, the proposed method is verified by experiments using a conductor system in which three circular conductors are arranged in a rectangular conductor. Calculated results obtained by the proposed method agree well with the measured results.

Noise Analysis and Performance Improvement of a MEMS Fabry-Pérot Seismic Accelerometer

MEMS accelerometers based on the optical interference technique play an important role in seismic wave detection due to their high resolution, strong electromagnetic stability, and low cost. This paper reports a MEMS Fabry-Perot seismic accelerometer. The working principle and transfer function were established to introduce the accelerometer. Noise sources that contribute to the output of the accelerometer were analyzed and predicted. To improve the performance of the accelerometer, the active temperature compensation, the appropriate laser driving current selection, and the laser modulation-demodulation technologies were adopted to reduce the noise. Experimental results show that the noise floor of the accelerometer was decreased from 11 μg/√Hz@1 Hz to 330 ng/√Hz@1 Hz.

Development of energy storage for high voltage electromagnetic pulse generator

Recently, much attention has been paid to electromagnetic stability in the development of energy storage devices, which makes it possible to maintain operating parameters during exposure to electromagnetic pulses and the consequences of their interaction. The issue of ensuring the electromagnetic stability of electronic equipment, due to the fact that under the influence of electromagnetic pulses in electronic and electrical circuits are overvoltage pulses, depending on the origin of electromagnetic pulses, distance from electromagnetic pulses source to hardware components amplitude, rise time and pulse duration can change. That is why the task of creating high-energy electromagnetic pulse generators remains extremely important for modern research. The main use of such generators is to study the interaction of thin-film layers of semiconductor materials with high-energy electromagnetic pulses and the development of elements to protect electronic equipment from the effects of electromagnetic pulses. A set of electromagnetic pulses generators has been created, the use of which will allow studying the properties of the protection elements of electronic equipment in a wide range of electromagnetic pulses capacities. In combination with the previously developed design of the electromagnetic pulses generator, this will affect the studied samples of electronic equipment and protection elements through the integrated operation of the electromagnetic pulses, which will have both high time and high energy. To ensure comfortable and safe research work, the device has a visual indication of operating modes, including modes of high DC voltage generation. The developed control device and power supply for the high-energy electromagnetic pulse generator meets the requirements established during its development and can be used to study the interaction of semiconductor thin-film layers with high-energy electromagnetic pulses.

Excellent Thermally Conducting Ni Plating Graphite Nanoplatelets/Poly(phenylene sulfone) Composites for High-Performance Electromagnetic Interference Shielding Effectiveness.

First, nickel particles were deposited on the surface of graphite nanoplatelets to fabricate highly conductive GnPs@Ni core-shell structure hybrid fillers via electroplating. The modified GnPs were blended with polyphenylene sulfone via the solution blending method, followed by the hot-pressing method to achieve high thermally conducting GnPs@Ni/PPSU composites for high performance electromagnetic interference effectiveness. The results showed that in-plane and through-plane thermal conductivity of the composite at the 40 wt% filler loading could reach 2.6 Wm−1K−1 and 3.7 Wm−1K−1, respectively, which were 9.4 and 20 times higher than that of pure PPSU resin. The orientation degree of fillers was discussed by XRD and SEM. Then, heat conduction data were fitted and analyzed by the Agari model, and the heat conduction mechanism was further explored. The testing results also demonstrated that the material exhibited good conductivity, electromagnetic shielding effectiveness and superior thermal stability. Overall, the GnPs@Ni/PPSU composites had high thermal conductivity and were effective electromagnetic shielding materials at high temperatures.

Small-signal modeling of LCC-HVDC systems with switching for electromagnetic timescale stability analyses of power systems

Small-signal modeling of LCC-HVDC systems with switching for electromagnetic timescale stability analyses of power systems

Design and Application of Early Warning Model for Electric Vehicle Charging Safety

In order to improve the charging safety of electric vehicles, it is necessary to design the early warning model of charging safety, so as to overcome the overload defects in the charging process of electric vehicles. An electric vehicle charging safety warning model was proposed based on contactless charging design. The electromagnetic induction coil and electromagnetic coupler installed on the charging pile are used to design the electromagnetic coupling induction with the driving electric vehicle tire wire, and the electromagnetic coupling control and charging stability adjustment of the electric vehicle are carried out by using the inductive power transmission technology. According to the overload regulation of electric vehicle during charging, the overload interruption control of electric vehicle charging is carried out by mutual inductance coupling method, and the parameters such as resonance frequency, mutual inductance coefficient and coil internal resistance during charging are analyzed. The parameter steady-state regulation method is used for non-contact charging, and the electric vehicle charging safety early warning control is realized, and the parameter optimization design of electric power transmission system in the process of electric vehicle charging is carried out. According to the parameter optimization result, the electric vehicle charging safety early warning test is realized. The test results show that the proposed method has good control performance and can effectively realize the wireless energy transmission of 100W in 100cm, the charging efficiency and the charging safety are improved.