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This paper presents the design and analysis of a high voltage gain converter utilizing a coupled inductor with reduced voltage stress, specifically for photovoltaic energy-based systems. The proposed converter employs a two-winding coupled inductor and voltage multiplier cells to achieve an increase in output voltage while mitigating voltage stress across semiconductor components. Additionally, the voltage multiplier cells function as voltage clamps for the power switch, further enhancing the converter's performance. The converter features a single switch design, which simplifies control, reduces cost, and improves reliability. Key advantages of the converter include a low component count, a common ground between input and output ports, and high efficiency. The converter's performance is thoroughly investigated through mode analysis and steady-state analysis. Comparative evaluations with similar converters are conducted to highlight the benefits and performance of the proposed design. To validate the theoretical analysis, a 125 W prototype with 26 V input and 200 V output voltages operating at a 50 kHz switching frequency is developed, and experimental results are presented, demonstrating the effectiveness and practicality of the proposed high voltage gain converter.
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High-voltage cables are the main arteries of urban power supply. Cable accessories are connecting components between different sections of cables or between cables and other electrical equipment. The stress in the cold shrink tube of cable accessories is a key parameter to ensure the stable operation of the power system. This paper attempts to explore a method for measuring the stress in the cold shrink tube of high-voltage cable accessories based on ultrasonic longitudinal wave attenuation. Firstly, a pulse ultrasonic longitudinal wave testing system based on FPGA is designed, where the ultrasonic sensor operates in a single-transmit, single-receive mode with a frequency of 3 MHz, a repetition frequency of 50 Hz, and a data acquisition and transmission frequency of 40 MHz. Then, through experiments and theoretical calculations, the transmission and attenuation characteristics of ultrasonic longitudinal waves in multi-layer elastic media are studied, revealing an exponential relationship between ultrasonic wave attenuation and the thickness of the cold shrink tube. Finally, by establishing a theoretical model of the radial stress of the cold shrink tube, using the thickness of the cold shrink tube as an intermediate variable, an effective measurement of the stress of the cold shrink tube was achieved.
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Ion mobility spectrometry is an emerging technology in trace gas analysis that has moved from typical safety and security applications to many other fields ranging from environmental and food quality monitoring to medicine and life sciences. Nevertheless, further dissemination, including the development of new instruments and the expansion into new fields of application requires the availability of the fundamental components of ion mobility spectrometers. For example, the electronics is essential for the analytical performance, but is only provided by specialized manufacturers due to specific requirements. In this paper, we present a modular, isolated high-voltage switch that can be operated at an isolated potential. The modular design enables tailoring its configuration to the required application. Each module can switch a voltage of up to 3 kV, and can be operated with an offset voltage of up to 7 kV. The switch has rise and fall times of less than 25 ns, making it suitable for a wide range of applications, e.g., in ion mobility spectrometry. Finally, the presented modular, isolated high-voltage switch was used in a push-pull configuration to generate the injection pulse of the ion gate. The new modular, isolated high-voltage switch shows similar performance compared to a commercially available high-voltage switch.
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Low-concentration ether electrolytes cannot efficiently achieve oxidation resistance and excellent interface behavior, resulting in severe electrolyte decomposition at a high voltage and ineffective electrode-electrolyte interphase. Herein, we utilize sandwich structure-like gel polymer electrolyte (GPE) to enhance the high voltage stability of potassium-ion batteries (PIBs). The GPE contact layer facilitates stable electrode-electrolyte interphase formation, and the GPE transport layer maintains good ionic transport, which enabled GPE to exhibit a wide electrochemical window and excellent electrochemical performance. In addition, Al corrosion under a high voltage is suppressed through the restriction of solvent molecules. Consequently, when using the designed GPE (based on 1 m), the K||graphite cell exhibits excellent cycling stability of 450 cycles with a capacity retention of 91%, and the K||FeFe-Prussian blue cell (2-4.2 V) delivers a high average Coulombic efficiency of 99.9% over 2200 cycles at 100 mA g-1. This study provides a promising path in the application of ether-based electrolytes in high-voltage and long-lasting PIBs.
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This study evaluated the ability of a high-voltage electrostatic field (HVEF) treatment to extend the shelf life of tomatoes. Tomatoes were exposed to HVEF treatment for different lengths of time, and the physicochemical properties of tomatoes and bioactive compounds were monitored during 28 days of storage at 4 °C. The results indicated that the quality parameters of tomatoes were better maintained during storage by the HVEF treatment relative to the control treatment, extending their shelf life by 14-28 days. The HVEF treatment mitigated losses in firmness, weight, color changes, and bioactive substances, such as total phenolic content, total flavonoid content, ascorbic acid, and lycopene. The activity of pectin-degrading enzymes was also inhibited. The best exposure times for the HVEF treatment were 90 and 120 min. While the measured parameters decreased in both the control and HVEF treatment groups, the decrease in all of these measured parameters was significantly less (p < 0.05) in the optimum HVEF treatment groups than in the control. While the physicochemical properties may vary between different tomato varieties, the HVEF treatment of harvested tomatoes for 90 or 120 min can mitigate the degradation of quality parameters and loss of bioactive compounds incurred during the postharvest storage of tomatoes, thus maintaining their commercial value.
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High pulse discharge breakage has a vast prospect as a fresh crushing mechanism for it has the capability to enhance the comminuting effect, however, the breaking mechanism is not yet well studied. In this orthogonal designed research, 27 indoor tests of high voltage pulse discharge (HVPD) for breaking concrete together with the determination of dynamic elastic modulus of concrete based on three variables, i.e. applied voltage, pulse number, and discharge electrode gap, were carried out at three levels. The effects of these factors were studied by using significance and range analysis. The results showed that among these factors, the pulse number has the greatest impact on the dynamic elastic modulus loss (DEML) of concrete, while the applied voltage has the least influence. By changing the value of pulse number and applied voltage, the DEML can be increased to 12.9% and 26.7%, respectively. The impact of the factors' combination was experimentally proven, and the resulting DEML of concrete broken by HVPD was obtained as 219.73 ± 9.58 MPa, which was 25.19% higher than the maximum of the DEML of concrete broken by HVPD in the orthogonal experiment under various individual factors. These findings provide technical references for improving the crushing efficiency of concrete materials and the engineering application of HVPD crushing technology.
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Magnesium-based batteries have garnered significant attention due to their high energy density, excellent intrinsic safety, and low cost. However, the application process has been hindered by the high Mg2+ ions diffusion barrier in solid-state structures and solid-liquid interphase. To address this issue, a hybrid battery technology based on Mg anode and Fe-based Prussian Blue Analogue cathode doped with functional transition metal ions and NâO bonds is proposed. Combined multiscale experimental characterizations with theoretical calculations, the subtle lattice distortion can create an asymmetric diffusion path for the active ions, which enables reversible extraction with significantly reduced diffusion barriers achieved by synergistic doping. The optimized cathode exhibits a working potential of 2.3 V and an initial discharge capacity of 152 mAh g-1 at 50 mA g-1. With the preferred electrolyte combined with equivalent concentration [Mg2(µ-Cl)2(DME)4][AlCl4]2 and NaTFSI salt solution, the hybrid system demonstrates superior cycling performance over 200 cycles at a high current density of 200 mA g-1, maintaining ≈100% coulombic efficiency with superior ion dynamic. The findings are expected to be marked an important step in the further application of high-voltage cathodes for Mg-based hybrid batteries.
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Ensuring the stability of high-voltage circuit breakers (HVCBs) is crucial for maintaining an uninterrupted supply of electricity. Existing fault diagnosis methods typically rely on extensive labeled datasets, which are challenging to obtain due to the unique operational contexts and complex mechanical structures of HVCBs. Additionally, these methods often cater to specific HVCB models and lack generalizability across different types, limiting their practical applicability. To address these challenges, we propose a novel cross-domain zero-shot learning (CDZSL) approach specifically designed for HVCB fault diagnosis. This approach incorporates an adaptive weighted fusion strategy that combines vibration and current signals. To bypass the constraints of manual fault semantics, we develop an automatic semantic construction method. Furthermore, a multi-channel residual convolutional neural network is engineered to distill deep, low-level features, ensuring robust cross-domain diagnostic capabilities. Our model is further enhanced with a local subspace embedding technique that effectively aligns semantic features within the embedding space. Comprehensive experimental evaluations demonstrate the superior performance of our CDZSL approach in diagnosing faults across various HVCB types.
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The development of cathode materials has always been one of the most crucial areas of research in the field of sodium-ion batteries. Sulfate-based polyanionic materials, known for their high working voltage characteristics, have received widespread attention. In this work, a fluoro-sulfate sodium-ion battery cathode material, Na3Fe2(SO4)3F modified with carbon nanotubes, was developed using a low-temperature solid-state annealing method. This Na3Fe2(SO4)3F cathode exhibits an exceptionally high voltage of 3.77 V, excellent discharge capacity (102 mAh/g at 0.1C), and good rate capability. This material broadens the research directions for cathode materials and holds promise as a foundation for the further development of high-performance sodium-ion batteries.
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Prussian blue analogues (PBAs) have attracted increasing attention in aqueous zinc-based batteries (AZBs) with the advantages of an open framework, adjustable redox potential, and easy synthesis. However, they exhibited a low specific capacity and a poor cycle performance. In this work, crystalline potassium iron hexacyanoferrate (FeHCF) with dislocation was designed and prepared by a poly(vinylpyrrolidone) (PVP) additive. The metastable state provided by PVP would cause an electrostatic interaction between cyanogen and water molecules. The reduced force increases the steric resistance of the water molecules entering the crystal. The low content of crystal water in FeHCF is associated with the formation of dislocation. The dislocation effect effectively improves the electrochemical reactivity and reaction kinetics of FeHCF. Thus, it presents a high reversible capacity of 131 mAh g-1 with a superior capacity retention of 85% after 550 cycles at 0.5 A g-1. When used as a cathode, the AZBs display a high voltage of 2.6 V, a fast charging capability (<5 min), and a satisfactory cycle stability with a capacity retention of 82% after 400 cycles at 0.2 A g-1 in decoupling electrolytes. This work provides an effective strategy for the design of high-performance PBA-based cathodes for 2.6 V AZBs.
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Combining high-voltage nickel-rich cathodes with lithium metal anodes is among the most promising approaches for achieving high-energy-density lithium batteries. However, most current electrolytes fail to simultaneously satisfy the compatibility requirements for the lithium metal anode and the tolerance for the ultra-high voltage NCM811 cathode. Here, we have designed an ultra-oxidation-resistant electrolyte by meticulously adjusting the composition of fluorinated carbonates. Our study reveals that a solid-electrolyte interphase (SEI) rich in LiF and Li2O is constructed on the lithium anode through the synergistic decomposition of the fluorinated solvents and PF6- anion, facilitating smooth lithium metal deposition. The superior oxidation resistance of our electrolyte enables the Li||NCM811 cell to deliver a capacity retention of 80% after 300 cycles at an ultrahigh cut-off voltage of 4.8 V. Additionally, a pioneering 4.8 V-class lithium metal pouch cell with an energy density of 462.2 Wh kg-1 stably cycles for 110 cycles under harsh conditions of high cathode loading (30 mg cm-2), low N/P ratio (1.18), and lean electrolytes (2.3 g Ah-1).
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In the development of lithium-ion batteries (LIBs), cheaper and safer solid polymer electrolytes are expected to replace combustible organic liquid electrolytes to meet the larger market demand. However, low ionic conductivity and inadequate cycling stability impede their commercial viability. Herein, a novel flexible conducting solid polymer electrolytes (CSPEs) based on polyvinyl alcohol (PVA) and ion-polarized diethylenetriaminepentaacetic acid (P-DETP) is developed for the first time and applied in LIBs. PVA and P-DETP form a compact polymer network through hydrogen bonding, enhancing the thermomechanical stability of CSPE while restricting the migration of larger anions. Furthermore, density functional theory calculations confirm that P-DETP can facilitate the dissociation of Li+-TFSI- via electrostatic attraction, resulting in increased mobility of lithium ions. Additionally, P-DETP contributes to the formation of a stable electrode-electrolyte interface layer, effectively suppressing the growth of lithium dendrites and improving antioxidant capacity. These synergistic effects enable CSPE to exhibit remarkable properties including high ionic conductivity (2.8 × 10-4 S cm-1), elevated electrochemical potential (5.1 V), and excellent lithium transference number (0.869). Notably, the P-DETP/LiTFSI CSPE demonstrates stable performance not only in LiFePO4 batteries but also adapts to high-nickel ternary LiNi0.88Co0.06Mn0.06O2 cathode, highlighting its immense potential for application in high energy density LIBs.
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INTRODUCTION: Impedance is a crucial parameter in cardiovascular implantable electronic devices (CIEDs). Clinically, most CIEDs measure impedance using low voltage sub-threshold measurement (LVSM). Although the LVSM of shock impedance (LVSM-SI) is generally comparable with high voltage shock impedance (HVSI), LVSM-SI might be inaccurate if peri-lead tissue degeneration occurs. METHODS AND RESULTS: We present a case of elevated LVSM-SI occurring 8 years post-lead implantation, possibly attributed to encapsulation of the right ventricular lead coil. After 0.1 J shock was delivered, a full output synchronized shock was administered to measure HVSI, revealing a normal value. Furthermore, LVSM-SI was normalized and maintained within the normal range during long-term follow-up. CONCLUSION: Our findings suggest conducting a full-output synchronized shock test to assess HVSI when abnormal LVSM-SI is detected in the remote phase post-ICD implantation, which may be considered to help normalize LVSM shock impedance.
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Solid polymer electrolytes (SPEs) represent a pivotal advance toward high-energy solid-state lithium metal batteries. However, inadequate interfacial contact remains a significant bottleneck, impeding scalability and application. Inadequate interfacial contact remains a significant bottleneck, impeding scalability and application. Recent efforts have focused on transforming liquid/solid interfaces into solid/solid ones through in situ polymerization, which shows potential especially in reducing interface impedance. Here, we designed high-voltage SSLMBs with dual-reinforced stable interfaces by combining interface modification with an in situ polymerization technology inspired by targeted effects in medicine. Theoretical calculations and time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis demonstrate that tetramethylene sulfone (TMS) and bis(2,2,2-trifluoromethyl) carbonate (TFEC) exhibit selective adsorption at the interface of the LiNi0.8Co0.1Mn0.1O2 (NCM) cathode and Li anode, respectively. These compounds further decompose to form a stable cathode-electrolyte interface (CEI) film and a solid electrolyte interface (SEI) film, thereby simultaneously achieving a superior interface between the SPE and both the Li anode and NCM cathode. The developed Li||SPE||Li cell sustained cycling for more than 1000 h at 0.3 mA cm-2, and the NCM||SPE||Li cell also demonstrated an excellent capacity retention of 86.8% after 1000 cycles at 1 °C. This work will provide valuable insights for the rational design of high-voltage SSLMBs with stable interfaces, leveraging in situ polymerization as a cornerstone technology.
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Lithium metal batteries (LMBs) with LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes have garnered significant interest as next-generation energy storage devices due to their high energy density. However, the instability of their electrode/electrolyte interfaces in regular carbonate electrolytes (RCEs) results in a rapid capacity decay. To address this, a colloid electrolyte consisting of Li3P nanoparticles uniformly dispersed in the RCE is developed by a one-step synthesis. This design concurrently creates stable cathode electrolyte interphase (CEI) and solid electrolyte interphase (SEI) on both electrode surfaces. The cathode interface derived from this colloid electrolyte significantly facilitates the decomposition of Li salts (LiPF6 and LiDFOB) on the cathode surface by weakening the P-F and B-F bonds. This in situ formed P/LiF-rich CEI effectively protects the NCM811 cathode from side reactions. Furthermore, the Li3P embedded in the SEI optimizes and homogenizes the Li-ion transport, enabling dendrite-free Li deposition. Compared to the RCE, the designed colloid electrolyte enables robust cathode and anode interfaces in NCM811||Li full cells, minimizing gas and dendrite formation, and delivering a superior capacity retention of 82% over 120 cycles at a 4.7 V cutoff voltage. This approach offers different insights into electrolyte regulation and explores alternative electrolyte shapes and formulations.
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BACKGROUND: Bipolar voltage amplitude is capable of helping determine the ideal lesion size index (LSI) setting during radiofrequency (RF) ablation for atrial fibrillation (AF). OBJECTIVE: To determine whether voltage-guided pulmonary vein isolation (PVI) is noninferior to conventional LSI-guided PVI in patients with nonvalvular AF. METHODS: This was a multicenter randomized trial conducted over a period of 12 months. The primary efficacy endpoints of the study were AF recurrence, atrial flutter, and/or atrial tachycardia, and the noninferiority margin was set at a hazard ratio of 1.4. The primary safety end point was a composite of procedure-related complications. RESULTS: A total of 370 patients underwent randomization; 189 and 181 were assigned to the voltage (underwent voltage-guided PVI) and control (underwent conventional LSI-guided PVI) groups, respectively. The primary efficacy endpoint occurred in 22 patients (12.0%) in the voltage group and 23 (12.9%) in the control group (1-year Kaplan-Meier event-free rate estimates, 88.0% and 87.1%, respectively; hazard ratio, 1.00; 95% confidence interval [CI], 0.80 1.25). The primary safety endpoints were 4.8% in the voltage group and 6.6% in the control group (p = 0.2791). PVI time was significantly shorter in the voltage group (35.7 ± 14.5 min vs. 39.7 ± 14.7 min, p < 0.001). CONCLUSION: Voltage-guided PVI was noninferior to conventional LSI-guided PVI with respect to efficacy in the treatment of patients with AF and its use significantly reduced procedure time.
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The structure-activity relationships of nonsolvating cosolvents for organosulfur-based electrolyte systems were revealed. The performance of nonsolvating dilutant fluorobenzene (FB) was compared to various fluorinated ether dilutants in high-voltage electrolytes containing a concentration of 1.2 M LiPF6 dissolved in fluoroethylene carbonate (FEC), ethyl methyl sulfone (EMS), and the dilutant. In a high-voltage and high-loading LiNi0.8Mn0.1Co0.1O2 (NMC811) full cell configuration, the organosulfur-based electrolyte containing FB dilutant enabled superior electrochemical performance compared to the electrolytes using other nonsolvating fluorinated ether formulations. Moreover, the FB-containing electrolyte exhibited the highest ionic conductivity and lowest viscosity among all organosulfur-based electrolytes containing nonsolvating dilutant. These improvements are attributed to the enhanced physical properties of electrolyte and lithium-ion mobility. Furthermore, by employing first-principles simulations, the observed suppression of side reactions at high voltage is linked to FB's lower reactivity toward singlet dioxygen, which is likely produced at the NMC interface. Overall, FB is considered an excellent diluent that does not impede cell operation by mass decomposition at the cathode.
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Na4Fe3(PO4)2P2O7 is regarded as the most promising polyanionic cathode for sodium-ion batteries (SIBs) due to its superior structural stability, cost-effectiveness, and environmental benignity. However, the low operating voltage inevitably weakens its competitiveness in energy density. Previous works have tried to enhance its operating voltage by Mn doping, which draws on the design idea of LiFexMn1-xPO4 cathode for lithium-ion batteries, but with little success. In this context, uncovering the role of Mn substitution in Na4Fe3-xMnx(PO4)2P2O7 (NFMxPP) cathode is urgently needed. This work discloses the effect of Mn contents on the structure, sodium storage property, and reaction mechanism of NFMxPP cathode for the first time. Introducing a moderate amount of Mn (0.6 ≤ x ≤ 1.2) into NFMxPP can weaken the Fe-O bonding interaction, thus leading to the full utilization of Mn3+/Mn2+ redox couple. As the representative, NFM1.2PP cathode exhibited a high operating voltage of ≈3.3 V with a reversible capacity of 109.2 mAh g-1. Note that a Hard carbon||NFM1.2PP full battery manifests considerably high-capacity retention of 92.3% over 1600 cycles. It is believed that an understanding of the role of Mn substitution in this work will promote the practical application of high voltage NFMxPP cathodes for SIBs.
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High-power converters with significant gains represent established configurations that hold appeal for applications in the industrial and commercial sectors, such as fuel cell electric vehicles (FCEV), energy backup systems, and automotive headlamps. Existing literature predominantly features topologies employing a single-duty ratio. However, this singular approach may not be dependable for operations with high-duty cycles, necessitating the incorporation of additional components to enhance voltage gain. To address this, the current study introduces the concept of time-sharing within the context of a high-gain non-isolated DC-DC converter. This innovative approach achieves substantially higher output voltage gains, approximately 13.33 times that of the input voltage. The analysis of the proposed converter is approached from various perspectives. Finally, it is examined within the MATLAB/Simulink environment, where the theoretical analysis is validated, and an efficiency of 97.4% is achieved.