Nanocomposite electret with surface potential self-recovery from water dipping for environmentally stable energy harvesting

Due to their high charge densities, electret materials have gained extensive attention in recent years for their abilities to harvest mechanical energy. However, the environmental stability of electret materials is still a major concern for real applications. Here, we report a thin-film nanocomposite electret material (NCEM) that exhibits immediate and effective self-recovery of the surface potential after water dipping. The NCEM is composed of a polytetrafluoroethylene (PTFE) film, a nanocomposite film with PTFE nanoparticles as the nanofiller and polydimethylsiloxane (PDMS) as the matrix. The surface potential of the NCEM resulting from corona charging could be stably maintained with very little decay of 2% after 25 days. More importantly, the surface potential exhibited quick self-recovery to 75% and 90% of its initial value after 10 min and 60 min, respectively, when the NCEM was removed from water. A 70% self-recovery was still observed even when the NCEM was dipped in water for 200 cycles. When used in electret nanogenerators (ENGs), the electric output recovered to 90% even when the ENG experienced water dipping. Therefore, this work presents a key step towards developing high-performance and environmentally stable energy harvesting nanogenerators that can survive harsh conditions for real applications

Boosting the Electron Beam Transmittance of Field Emission Cathode Using a Self-Charging Gate

The gate-type carbon nanotubes cathodes exhibit advantages in long-term stable emission owing to the uniformity of electrical field on the carbon nanotubes, but the gate inevitably reduces the transmittance of electron beam, posing challenges for system stabilities. In this work, we introduce electron beam focusing technique using the self-charging SiNx/Au/Si gate. The potential of SiNx is measured to be approximately −60 V quickly after the cathode turning on, the negative potential can be maintained as the emission goes on. The charged surface generates rebounding electrostatic forces on the following electrons, significantly focusing the electron beam on the center of gate hole and allowing them to pass through gate with minimal interceptions. An average transmittance of 96.17% is observed during 550 hours prototype test, the transmittance above 95% is recorded for the cathode current from 2.14 μA to 3.25 mA with the current density up to 17.54 mA cm−2

Pioglitazone Protects Against Renal Ischemia-Reperfusion Injury via the AMP-Activated Protein Kinase-Regulated Autophagy Pathway

Renal ischemia-reperfusion injury (IRI) is a major cause of acute renal failure. Our previous studies have shown that pioglitazone, a peroxisome proliferators-activated receptor (PPAR)-γ agonist used in type 2 diabetes, protects against renal IRI; however, the molecular mechanism underlying the renoprotective effects of pioglitazone is still unclear. In this study, we investigated the role of AMP-activated protein kinase (AMPK)-regulated autophagy in renoprotection by pioglitazone in IRI. To investigate whether pioglitazone protects renal cells from IRI, an in vivo renal IRI model was used. Cell apoptosis in the kidneys was determined by TUNEL staining. Western blotting was used to determine the expression of AMPK, autophagy-related proteins, and caspase-3/8 proteins in the kidneys. In a rat model of IRI, pioglitazone decreased the increased serum creatinine and urea nitrogen, improved renal histological score, and decreased the cell injury. Pioglitazone also increased AMPK phosphorylation, inhibited p62 and cleaved caspase-3/8 proteins, and activated autophagy-related proteins LC3 II and Beclin-1 in the kidneys of IRI rats. Moreover, GW9662, as a selective inhibitor of PPAR-γ, inhibited the protective effects of pioglitazone. These results suggest that pioglitazone exerts its protective effects in renal IRI via activation of an AMPK-regulated autophagy signaling pathway

A Resonant Lorentz-Force Magnetometer Exploiting Blue Sideband Actuation to Enhance Sensitivity and Resolution

This paper reports a miniaturized resonant Lorentz-force magnetometer that exploits blue-sideband actuation to attain a better sensitivity and resolution. The resonant magnetometer consists of a double-ended tuning fork (DETF) resonator with cavity slots to optimize thermoelastic dissipation, as well as a Lorentz-force generator structure to transduce the magnetic force to the axial of the resonator. The proposed device demonstrates a Lorentz-force sensitivity of 5.5 mV/nN, a noise floor of 1.25 μV/ √ Hz, and a resolution of 0.23 pN/ √ Hz. In comparison with a conventional drive scheme, the blue- sideband actuation achieves approximately two orders of magnitude improvement regarding sensitivity and resolution than that of the amplitude modulation (AM) readout and 3.6-fold enhancement than that of the frequency modulation (FM) readout. The results affirm the merit of the novel excitation method and provide solid evidence of its effectiveness in practical applications

An Efficient Self-Powered Seawater Desalination System Based on a Wind-Driven Radial-Arrayed Rotary Triboelectric Nanogenerator

Seawater desalination (SD) is regarded as one of the most effective solutions to the shortage of fresh water in many desert and island areas. However, high energy consumption and environmental pollution impede its development. Herein, a self-powered seawater desalination (SP-SD) system is proposed to reduce energy consumption and environmental pollution by using a wind-driven radial-arrayed rotary triboelectric nanogenerator (RAR-TENG). As expected, the SP-SD unit achieves a high desalination capacity of 10.5 mg/h for the 0.17 M NaCl solution at a rotation speed of 350 rpm with a hydrogen (H2) production rate of 5.6 × 10–4 mL/s, which is superior to most previous reported results. Moreover, the SP-SD system could easily reach a desalination capacity of 2.4 mg/h at a low wind speed of 6 m/s by using natural wind energy. This wind-driven SP-SD system contributes an innovative approach to the field of environmental electrochemistry

An Efficient Self-Powered Seawater Desalination System Based on a Wind-Driven Radial-Arrayed Rotary Triboelectric Nanogenerator

Seawater desalination (SD) is regarded as one of the most effective solutions to the shortage of fresh water in many desert and island areas. However, high energy consumption and environmental pollution impede its development. Herein, a self-powered seawater desalination (SP-SD) system is proposed to reduce energy consumption and environmental pollution by using a wind-driven radial-arrayed rotary triboelectric nanogenerator (RAR-TENG). As expected, the SP-SD unit achieves a high desalination capacity of 10.5 mg/h for the 0.17 M NaCl solution at a rotation speed of 350 rpm with a hydrogen (H2) production rate of 5.6 × 10–4 mL/s, which is superior to most previous reported results. Moreover, the SP-SD system could easily reach a desalination capacity of 2.4 mg/h at a low wind speed of 6 m/s by using natural wind energy. This wind-driven SP-SD system contributes an innovative approach to the field of environmental electrochemistry

An Efficient Self-Powered Seawater Desalination System Based on a Wind-Driven Radial-Arrayed Rotary Triboelectric Nanogenerator

Seawater desalination (SD) is regarded as one of the most effective solutions to the shortage of fresh water in many desert and island areas. However, high energy consumption and environmental pollution impede its development. Herein, a self-powered seawater desalination (SP-SD) system is proposed to reduce energy consumption and environmental pollution by using a wind-driven radial-arrayed rotary triboelectric nanogenerator (RAR-TENG). As expected, the SP-SD unit achieves a high desalination capacity of 10.5 mg/h for the 0.17 M NaCl solution at a rotation speed of 350 rpm with a hydrogen (H2) production rate of 5.6 × 10–4 mL/s, which is superior to most previous reported results. Moreover, the SP-SD system could easily reach a desalination capacity of 2.4 mg/h at a low wind speed of 6 m/s by using natural wind energy. This wind-driven SP-SD system contributes an innovative approach to the field of environmental electrochemistry

Boosting the electron beam transmittance of field emission cathode using a self-charging gate

Abstract The gate-type carbon nanotubes cathodes exhibit advantages in long-term stable emission owing to the uniformity of electrical field on the carbon nanotubes, but the gate inevitably reduces the transmittance of electron beam, posing challenges for system stabilities. In this work, we introduce electron beam focusing technique using the self-charging SiNx/Au/Si gate. The potential of SiNx is measured to be approximately −60 V quickly after the cathode turning on, the negative potential can be maintained as the emission goes on. The charged surface generates rebounding electrostatic forces on the following electrons, significantly focusing the electron beam on the center of gate hole and allowing them to pass through gate with minimal interceptions. An average transmittance of 96.17% is observed during 550 hours prototype test, the transmittance above 95% is recorded for the cathode current from 2.14 μA to 3.25 mA with the current density up to 17.54 mA cm−2

Fully Rollable Lead-Free Poly(vinylidene fluoride)-Niobate-Based Nanogenerator with Ultra-Flexible Nano-Network Electrodes

A fully rollable nanocomposite-based nanogenerator (NCG) is developed by integrating a lead-free piezoelectric hybrid layer with a type of nanofiber-supported silver nanowire (AgNW) network as electrodes. The thin-film nanocomposite is composed of electroactive polyvinylidene fluoride (PVDF) polymer matrix and compositionally modified potassium sodium niobate-based nanoparticles (NPs) with a high piezoelectric coefficient (<i>d</i>₃₃) of 53 pm/V, which is revealed by the piezoresponse force microscopy measurements. Under periodical agitation at a compressive force of 50 N and 1 Hz, the NCG can steadily render high electric output up to an open-circuit voltage of 18 V and a short-circuit current of 2.6 μA. Of particular importance is the decent rollability of the NCG, as indicated by the negligible decay in the electric output after it being repeatedly rolled around a gel pen for 200 cycles. Besides, the biocompatible NCG can potentially be used to scavenge biomechanical energy from low-frequency human motions, as demonstrated by the scenarios of walking and elbow joint movement. These results rationally expand the feasibility of the developed NCG toward applications in lightweight, diminutive, and multifunctional rollable or wearable electronic devices