High-voltage pulsed generators are essential excitation sources for low-temperature plasma (LTP) generation. Conventional topologies combining solid-state switches and pulse transformers often suffer from undesirable waveform distortion and excessive rise time in the output pulse. To address these limitations, this work proposed an equivalent pulse transformer model based on the input-parallel, output-series (IPOS) topology, systematically investigating the influence of transformer quantity and turns ratio on pulsed voltage waveform. The results revealed that increasing the number of transformers elevates leakage inductance, thereby extending the rise time and reducing voltage gain. Furthermore, strategic optimization of both transformer quantity and turns ratio enables effective leakage inductance suppression, thereby shortening rise times and enhancing voltage gain while maintaining the ideal step-up ratio. Finally, a high-frequency modulated, bipolar nanosecond pulsed generator was subsequently designed and tested, achieving output voltages up to 8.5 kV, pulse durations of 500 ns (FWHM), frequency of 47kHz in a burst mode, and rise times as short as 180 ns. The prototype successfully powered a surface dielectric barrier discharge (DBD) reactor for controllable ozone production. This work offers critical guidelines for parasitic parameter optimization in IPOS-based, multitransformer high-voltage pulsed generators, advancing their performance in plasma applications.

The dielectric barrier discharge (DBD) plasma actuator-based anti-icing and de-icing technology, known for its rapid response and simple structure, has been deployed as a novel anti-icing/de-icing solution. However, the current three-electrode DBD configuration, typified by the sliding discharge (SD), suffers from issues such as poor uniformity in plasma and temperature distribution, low heating rate, and a tendency for spark discharge during sustained operation. To enhance the thermal effects of DBD plasma, this study proposes a three-electrode DBD structure with a suspension electrode. Specifically, the surface electrode (S) is suspended and overlaps with half of the embedded high-voltage electrodes. Experimental results show that, compared with SD, under conditions where the plasma fully covers the surface electrode gap, the three-electrode DBD (TDBD) in this study can achieve a coexistence of both surface DBD and coplanar DBD discharge modes. Within 15 s, an average temperature field of 80 degrees C can be established, which is only one-tenth of the time required for SD, while achieving a more uniform plasma and temperature distribution on a macroscopic scale. During the first 2 min, the anti-icing/de-icing heat distribution area exceeds twice that of SD. Additionally, the proposed structure is less prone to spark discharge during long-term operation, avoiding the negative effects of spark discharge on device lifespan. In conclusion, the TDBD proposed demonstrates superior thermal effects compared to SD, and its design principles could provide theoretical support for multi-electrode discharge theory and discharge zone control technologies. It is expected to offer valuable insights for the future design of plasma actuators in aviation anti-icing and de-icing applications.

Medium-voltage direct current air circuit breakers (DCACBs) are critical components in ensuring the safe and stable operation of medium-voltage direct current power systems. However, the development of DCACBs capable of high-current interruption with enhanced efficiency remains a technological challenge. This study investigates the interruption of a 100-kA short-circuit current at 4kV by proposing a novel arc chamber design with an optimized splitter plate configuration. Unlike conventional arc chambers employing uniformly spaced splitter plates, the proposed design features a nonuniformly spaced, arc-shaped arrangement following a normal distribution. Based on magnetohydrodynamic (MHD) theory, a comparative analysis of arc characteristics was conducted between the two configurations. The spatiotemporal distributions of arc temperature and current density as well as the waveforms of voltage and current were systematically analyzed. It reveals that the proposed design reduces arc duration from 4.8ms for the conventional arc chambers to 3.7ms while decreasing the number of splitter plates from 37to 27. Additionally, the mole fraction of copper vapor from electrode erosion decreases from 12% for the conventional arc chambers to 10.59%. Detailed analysis shows that it is attributed to the enhanced Lorentz forces on the arc column, the increased arc-cutting efficiency of splitter plates, and the effective arc elongation due to the arc-shaped configuration. This study provides a quantifiable theoretical foundation and technical reference for the optimized design of high-current DCACBs.

ABSTRACT Exudate‐induced discharge dark zones pose a major bottleneck for flexible coplanar dielectric barrier discharge (CDBD) devices in wound healing applications, as they compromise treatment uniformity and reliability. To address this, we innovatively compare expanded polytetrafluoroethylene and medical gauze layers introduced onto flexible CDBD devices, focusing on their ability to suppress exudate while maintaining adequate gas transport. The key finding is that gauze consistently outperforms ePTFE in both exudate suppression and gas transport capability. This is probably because that gauze's macroporous network directs liquid through thickness, while ePTFE's micropores induce lateral spreading. These results provide a practical basis for selecting covering materials to stabilize discharge and improve the performance of plasma‐based wound therapy.

Flexible cold atmospheric-pressure plasma (CAP) devices hold great promise for biomedical applications, where flexible materials and specialized structures enable secure contact with the body surface and effective delivery of reactive species. However, a fundamental trade-off exists among discharge area, operating voltage, and surface temperature, which limits performance and thermal safety. To address this, we developed a multilayer flexible CAP device with a large discharge area, low surface temperature and operating voltage, tailored for wound treatment and sterilization. A porous silicone layer confines the discharge within an array of holes, with the discharge area and voltage quantitatively linked to hole size and silicone thickness via an equivalent circuit model. Electro-thermal field simulations, based on dielectric barrier discharge energy conversion efficiency, were used to determine the maximum allowable input power under thermal safety constraints. A prototype device demonstrated a 1380 mm(2) discharge area and a maximum surface temperature of 35.1 degrees C under 5 kV pulsed voltage. In vitro experiments showed >99% inactivation of Staphylococcus aureus after 40 s of plasma exposure. This work presents a generalizable framework for designing high-performance flexible plasma devices with strong potential for wearable biomedical applications.

Abstract Flexible dielectric barrier discharge (FDBD) devices are promising plasma sources for thermally sensitive plasma-treatment scenarios and potential biomedical applications for their flexibility and conformal adaptability. However, continuous discharge can cause surface heat accumulation, which may further contribute to thermally induced discharge-state drift. In this study, a feedback closed-loop surface-temperature regulation method is developed for an FDBD device. An infrared sensor is used to monitor the two-dimensional temperature field, and the average surface temperature in the discharge region is selected as the controlled target. Open-loop experiments at different driving frequencies are used to identify a first-order thermal model, with the pulse frequency serving as the manipulated variable for regulating the energy input. Based on this model, PI and BP-PID controllers are implemented as two closed-loop control strategies on an STM32 embedded platform. The closed-loop experiments show that the average surface temperature tracks the selected setpoints of 34, 37, and 40 °C, with the BP-PID implementation providing improved tracking and disturbance-rejection behavior relative to the PI baseline. Optical-emission analysis further shows that the spectral intensity ratio I 391.4 / I 337.1 , used here as an E/N -sensitive optical proxy for relative variations in the excitation conditions, exhibits a positive long-term drift under open-loop operation. This drift is weakened under active temperature control, indicating that closed-loop thermal regulation can reduce the long-term variation of the E/N -sensitive optical proxy during continuous FDBD operation. The results provide an experimental basis for the active thermal regulation of FDBD systems to achieve stable, repeatable operation in thermally sensitive plasma applications.

Transformer oil is a widely-used insulating medium in power equipment. As a promising and environmentally friendly substitute, vegetable insulating oil has attracted substantial global research attention. While substantial research efforts have been devoted to enhancing the macroscopic performance of vegetable insulating oils, the underlying molecular mechanisms are not well understood. A crucial challenge lies in clarifying the correlation between its molecular structure and macroscopic electrical properties. To address this, we propose the “equivalent degree of unsaturation” (Ωeq), a probabilistic metric that accurately characterizes the overall unsaturation of vegetable oils. A comparative study of cottonseed and peanut oils is carried out, integrating the analysis of their triglyceride molecular orbitals and chemical bonding with macroscopic voltage withstand tests under various temperatures and aging stages. The findings show that the key triglyceride molecules in peanut oil exhibit a larger energy gap and marginally stronger chemical bonding than those in cottonseed oil; the analysis of hydrolysis free energy variations further verifies the superior molecular stability of peanut oil, in contrast to the higher reactivity of cottonseed oil. The macroscopic tests consistently show that peanut oil maintains its dielectric strength more effectively under thermal and aging stress. The remarkable consistency between micro-scale simulations and macroscale experiments validates Ωeq as a powerful descriptor, providing a fundamental basis for the molecular design of next-generation vegetable insulating oils.

The performance of dielectric barrier discharge (DBD) ozone generators is strongly influenced by environmental conditions, yet the underlying mechanisms remain insufficiently quantified. In this work, a controlled-climate experimental platform and an AC-modulated surface dielectric barrier discharge (SDBD) reactor were developed to investigate the independent effects of gas temperature and humidity on ozone production. Measurements conducted at 10–50 °C and 40–90

ABSTRACT Cold atmospheric plasma (CAP) has garnered significant attention for its remarkable biomedical effects. With advances in flexible electronics and materials engineering, the integration of wearable design concepts into CAP systems has emerged as a promising direction to enable continuous, personalized, and user‐friendly medical treatment. This review comprehensively summarizes recent progress in flexible wearable CAP devices, which primarily rely on flexible dielectric barrier discharge (FXDBD) configurations implemented as patches or fabrics. The article systematically examines material selection spanning dielectrics, conductive electrodes, and functional substrates, as well as advanced manufacturing processes such as flexible printed circuit (FPC). Furthermore, it discusses power supply design and control strategies tailored for portable operation and safety compliance. Despite these advancements, current systems still face challenges in power autonomy, real‐time sensing, and adaptive control. Future development should focus on integrating intelligent feedback mechanisms, multimodal sensors, and artificial intelligence to enable responsive and personalized plasma therapy. It also addresses critical biosafety aspects, including UV exposure, electrical currents, and reactive species concentrations. By offering a thorough analysis of device architectures, material options, fabrication techniques, and emerging applications, this work aims to provide valuable insights to guide future research in developing next‐generation wearable CAP systems for precision medicine and personalized healthcare.

Dielectric barrier discharge (DBD) has promising applications in aircraft anti-icing and de-icing due to plasma thermal effects, while enabling active flow control in specific topologies. This study pioneers the investigation of dark zone phenomena in a three-electrode DBD configuration featuring a suspension electrode-a critical distinction beyond conventional DBD system. Experimental results revealed that dark zone phenomenon would be appeared when the suspension electrode covered a certain number of buried electrodes, or was laid in a small range before and after the corresponding position. Quantitative analysis enabled classification of discharge suppression into two mechanistic modes: strong suppression mode and weak suppression mode. Theoretical modeling demonstrated that the local dark zone mechanism was attributed to the superposition of electric fields between electrodes. This fundamental understanding establishes a predictive framework for discharge pattern in multi-electrode plasma systems. The proposed dark zone regulation theory can also facilitate further applications in fields such as anti-icing and de-icing, material modification.

Polytetrafluoroethylene (PTFE) is widely used as an electrical insulating material due to its chemical stability and excellent dielectric properties. However, its high surface resistivity leads to charge accumulation, distorting the local electric field, reducing flashover voltage, and compromising the reliability of high-voltage equipment. This study employs atmospheric-pressure dielectric barrier discharge (DBD) plasma to modify PTFE surfaces, effectively reducing resistivity and enhancing charge dissipation. A 90-s continuous DBD treatment optimally reduces resistivity without thermal damage, while prolonged treatment causes thermal energy accumulation and surface sintering. A segmented modification approach with cooling intervals effectively mitigates thermal effects, maintaining resistivity reduction and preventing damage. By allowing cooling intervals between modifications, the segmented treatment method ensures that the surface temperature does not accumulate excessively, preserving the integrity of the material. Moreover, this method enables consistent improvements in resistivity, making it more effective than continuous treatment in preventing thermal damage. Plasma treatment introduces oxygen-containing functional groups and increases surface roughness, enhancing charge mobility. This scalable, cost-effective method offers a promising solution for improving PTFE's electrical performance, contributing to the reliability of power equipment in high-voltage applications and harsh environments.

Non-thermal atmospheric plasma has attracted increasing interest in plasma medicine, where precise and reliable dose delivery remains a key challenge under variable operating environments. In surface dielectric barrier discharge (SDBD) systems, ozone is a practically measurable dose-related output that is strongly affected by excitation frequency and environmental temperature and humidity. This work proposes an intelligent control framework that separates offline modeling from embedded real-time control. A long short-term memory (LSTM) network was trained offline to capture ozone-generation dynamics under coupled temperature-humidity variations, and Shapley additive explanations (SHAP) analysis was used to examine consistency with expected physical trends, yielding an interpretable surrogate model for simulation-based benchmarking. For embedded implementation, a lightweight model predictive controller using a nonlinear autoregressive network with exogenous inputs (NARX-MPC) was developed to balance accuracy and computational cost. With the LSTM surrogate model as the plant model, NARX-MPC was benchmarked against a baseline proportional-integral-derivative (PID) controller over a broad range of coupled temperature-humidity disturbance scenarios. Experiments under representative operating conditions showed that NARX-MPC markedly improved ozone regulation versus PID, reducing overshoot by 82%, settling time by 68%, and mean absolute error by 25%. These results support the feasibility of ozone dose regulation in plasma medicine and provide a basis for precise and reliable dose delivery under therapeutically relevant environmental disturbances.

Flexible dielectric barrier discharge (FDBD) is characterized by near-room-temperature, low-power operation and mechanical flexibility, and shows strong potential for air disinfection and skin-contact therapies. However, continuous discharge can cause local heat accumulation that modifies reactive-species distributions and risks thermal skin damage, so safe and controllable surface temperature has become a key requirement. In this study, an infrared thermal imaging sensor is employed to monitor the temperature distribution in the discharge region in real time. A first-order temperature-rise model is identified from open-loop experiments, and the corresponding transfer function is derived. Based on this model, a PI controller is designed and implemented on an STM32 microcontroller to regulate the average temperature in the discharge area. Experimental results show that, compared with open-loop operation, the proposed closed-loop scheme shortens the temperature rise time, suppresses excessive heating and improves robustness to disturbances, thereby enhancing the safety and biocompatibility of FDBD in medical applications.

Aiming at the special application requirements of high-voltage submarine cables, this paper proposes a PE-GFRP composite structure and carries out its insulation design. The structure uses glass fiber reinforced plastic (GFRP) as the outer layer of the cable and polyethylene (PE) as the main insulating material in the inner layer. The study systematically analyzed the withstand voltage characteristics of the two materials at different insulation thicknesses and evaluated the leakage current characteristics of the composite structure. In addition, the discharge process of the insulating material is thoroughly investigated through numerical simulation, which visualizes the sprouting and expansion of electric dendrites at different discharge stages and their possible insulation failure mechanisms. The results show that the proposed PE-GFRP composite structure can meet the insulation requirements of high-voltage submarine cables and has good application prospects.

The operation of cascaded arc jets in arc-heated wind tunnels for thermal protection material testing has largely been limited to inert gases, nitrogen gas or their mixtures. As a result, the plasma parameters of air or N2/O2 mixture cascade arc jet have not been extensively characterized. In this study, an N2/O2 cascaded arc jet was generated using a decoupled injection scheme, in which nitrogen was introduced upstream near the cathode and oxygen was injected downstream through a symmetric six-hole nozzle. This configuration produced an air-equivalent arc jet while reducing cathode oxidation and ablation. Optical emission spectroscopy and Langmuir probes were used to obtain spatially resolved plasma parameters. At an arc current of 50 A and a total flow rate of 2 slm, the rotational temperature, vibrational temperature, and maximum electron density were 1950 K, 3750 K, and 3.41×1017 m-3, respectively. Radial profiles decreased monotonically from the jet center to the edge, while axial profiles decayed downstream from the nozzle exit. Electron and current densities increased with gas flow rate and arc current, consistent with enhanced collisional ionization. These results provide quantitative data for N2/O2 cascaded arc jets and support improved thermal protection material testing and high purity flow simulation.

Ground simulation of the plasma sheath environment for hypersonic vehicles is commonly achieved using the arc jet. However, electrode ablation can introduce significant contamination that alters the flow properties. In this study, we employ the direct simulation Monte Carlo (DSMC) method to model an N2/O2 cascaded arc jet flow field, with the dual objectives of characterizing the flow and quantifying the effect of electrode ablation. The simulation reveals that during the jet expansion process, the flow attains a Mach number of 5.6, a temperature of 2277 K, and a velocity of 2376 m/s. Notably, the introduction of copper vapor at a concentration of only 200 ppm into the N2/O2 gas leads to a significant reduction in the Mach number, temperature, and velocity. An experimental N2/O2 cascaded arc jet system was constructed, and the simulated gas temperatures show good agreement with experimental measurements. This work provides an important reference for controlling flow contamination in arc-jet-simulated plasma sheath environments.

Real-time assessment of exudate levels under dressing-covered conditions is a critical unmet need in wound treatment using flexible coplanar dielectric barrier discharge (CDBD) patches, as exudate accumulation directly compromises discharge stability and therapeutic efficacy. To address this challenge, we propose a novel data-driven multimodal method for exudate-level grading that, for the first time, enables grading without removing the dressing. In a simulated gauze-covered patch application, using physiological saline to mimic exudate, we constructed a synchronized dataset comprising visible-light discharge images, infrared images, and current waveforms. Four distinct exudate levels were defined. For each modality, dedicated convolutional neural network (CNN) models were developed: two dimensional (2D)-CNNs for the image modalities and one dimensional (1D)-CNN for the current time series, with dynamic time warping as a baseline. The results demonstrate that the visible-light 2D-CNN achieves 100% accuracy, the infrared 2D-CNN achieves 98% accuracy, and the current-waveform 1D-CNN achieves an overall accuracy of 99.3%, with class-wise accuracies ranging from 98% to 100%. More importantly, while the visible-light image modality yields the best classification performance under controlled conditions, it requires external optical access, limiting its practical use under dressings. In contrast, the current waveform enables comparably high accuracy without optical observation and is far easier to integrate. These findings indicate that current-waveform-based monitoring is a practical and scalable solution for online exudate monitoring, providing a direct foundation for closed-loop control of CDBD-based wound therapy and representing a significant step toward intelligent, adaptive wound care.

A portable plasma water treatment (PWT) system, integrating a flexible coplanar dielectric barrier discharge (FCDBD) and a bipolar nanosecond pulse generator (BNPG), is designed for water sterilization. The FCDBD produces reactive species that are transported into water as microbubbles. This paper analyzes the discharge characteristics of BNPG-driven FCDBD via electrical diagnostics, optical emission spectroscopy (OES), liquid-phase plasma-activated species diagnostics, and ozone quantification. This FCDBD-based PWT system achieves a more than 5-log reduction of Escherichia coli in 800 mL of water within 5 min, yielding a high bacterial inactivation energy efficiency (BIEE) of 3.64 & times; 106 CFU/J. By prolonging the residence time of high-concentration ozone microbubbles at a low gas flow rate, the system presents a viable approach to outdoor water sterilization.

The gas temperature of arc plasma is an essential parameter in studies of the motion and extinguishment of arc, the recovery of gas insulation, and electrode erosion caused by arc discharge. This work measured the spatial distribution of the gas temperature by high-speed shadow imaging of the variation of the arc-induced flow field, which was confirmed by the Boltzmann plot method of the emission of the excited states of copper atoms. A typical low-current dc arc from photovoltaic arc faults was generated in the open air. The results showed that the gas temperature near the cathode was higher than that near the anode, which was different from the arc discharge of a high-current dc arc. It was interesting to observe a dispersed high-temperature region in the upper left, away from the cathode, which was independent of the direction of the electrode movement. When the arc current increased, the high-temperature region became elongated and then connected with the cathode. Detailed analysis of the flow field and the radiation light of the arc showed that the high-temperature region was probably caused by the electrode jet phenomenon of arc discharge.

Modeling arc–solid interaction precisely in medium-voltage DC air circuit breakers is challenging due to the complex processes of electrode erosion and metal vaporization during arc discharge. This study develops a DC air arc model based on magnetohydrodynamics (MHD) theory, which incorporates the time-varying copper vapor–air mixture along the arc's motion, rather than a fixed ratio of copper vapor. The model integrates a database containing the gas properties of copper vapor–air mixture, arc current, and the copper vapor mole fraction derived from pure air arc simulation. In the MHD model considering electrode erosion, the physical properties of the copper vapor–air mixture are updated at each time step based on the copper vapor mole fraction and the arc current. The simulation results of arc current and arc voltage during the breaking process are consistent with the experimental results. Additionally, the effects of different types and numbers of splitter plates, as well as short-circuit current on arc motion, are investigated. The arc duration time with laminated hybrid splitter plates is the shortest compared to fully ferromagnetic, fully insulated, and connected hybrid splitter plates. When the number of splitter plates increases from 7 to 67, the arc duration time is significantly reduced until saturation. Furthermore, as the short-circuit current decreases from 120 to 20 kA, the copper electrode erosion decreases substantially and finally stabilizes. This study presents an improved MHD model for arc motion in a time-varying copper vapor–air mixture, which is useful for the optimization of medium-voltage DC air circuit breakers.