63 research outputs found

    Tunable polarization-drived superior energy storage performance in PbZrO3 thin films

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    Antiferroelectric PbZrO3 (AFE PZO) films have great potential to be used as the energy storage dielectrics due to the unique electric field (E)-induced phase transition character. However, the phase transition process always accompanies a polarization (P) hysteresis effect that induces the large energy loss (Wloss) and lowers the breakdown strength (EBDS), leading to the inferior energy storage density (Wrec) as well as low efficiency. In this work, the synergistic strategies by doping smaller ions of Li+–Al3+ to substitute Pb2+ and lowering the annealing temperature (T) from 700 to 550 ℃ are proposed to change the microstructures and tune the polarization characters of PZO films, except to dramatically improve the energy storage performances. The prepared Pb(1−x)(Li0.5Al0.5)xZrO3 (P(1−x)(L0.5A0.5)xZO) films exhibit ferroelectric (FE)-like rather than AFE character once the doping content of Li+–Al3+ ions reaches 6 mol%, accompanying a significant improvement of Wrec of 49.09 J/cm3, but the energy storage efficiency (η) is only 47.94% due to the long-correlation of FE domains. Accordingly, the low-temperature annealing is carried out to reduce the crystalline degree and the P loss. P0.94(L0.5A0.5)0.06ZO films annealed at 550 ℃ deliver a linear-like polarization behavior rather than FE-like behavior annealed at 700 ℃, and the lowered remanent polarization (Pr) as well as improved EBDS (4814 kV/cm) results in the superior Wrec of 58.7 J/cm3 and efficiency of 79.16%, simultaneously possessing excellent frequency and temperature stability and good electric fatigue tolerance

    Significantly improved high-temperature energy storage performance of commercial BOPP films by utilizing ultraviolet grafting modification

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    Commercial biaxially oriented polypropylene (BOPP) film capacitors have been widely applied in the fields of electrical and electronic engineering. However, due to the sharp increase in electrical conduction loss as the temperature rises, the energy storage performance of BOPP films seriously degrades at elevated temperatures. In this study, the grafting modification method is facile and suitable for large-scale industrial manufacturing and has been proposed to increase the high-temperature energy storage performance of commercial BOPP films for the first time. Specifically, acrylic acid (AA) as a polar organic molecular is used to graft onto the surface of commercial BOPP films by using ultraviolet irradiation (abbreviated as BOPP−AA). The results demonstrate that the AA grafting modification not only slightly increases the dielectric constant, but also significantly reduces the leakage current density at high-temperature, greatly improving the high-temperature energy storage performance. The modified BOPP−AA films display a discharged energy density of 1.32 J/cm3 with an efficiency of >90% at 370 kV/mm and 125 °C, which is 474% higher than that of the pristine BOPP films. This work manifests that utilizing ultraviolet grafting modification is a very efficient way to improve the high-temperature energy storage performance of commercial BOPP films as well as provides a hitherto unexplored opportunity for large-scalable production applications

    Genomic data for 78 chickens from 14 populations

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    Background: Since the domestication of the red jungle fowls (Gallus gallus; dating back to~10 000 B.P.) in Asia, domestic chickens (Gallus gallus domesticus) have been subjected to the combined effects of natural selection and human-driven artificial selection; this has resulted in marked phenotypic diversity in a number of traits, including behavior, body composition, egg production, and skin color. Population genomic variations through diversifying selection have not been fully investigated. Findings: The whole genomes of 78 domestic chickens were sequenced to an average of 18-fold coverage for each bird. By combining this data with publicly available genomes of five wild red jungle fowls and eight Xishuangbanna game fowls, we conducted a comprehensive comparative genomics analysis of 91 chickens from 17 populations. After aligning ~21.30 gigabases (Gb) of high-quality data from each individual to the reference chicken genome, we identified ~6.44 million (M) single nucleotide polymorphisms (SNPs) for each population. These SNPs included 1.10 M novel SNPs in 17 populations that were absent in the current chicken dbSNP (Build 145) entries. Conclusions: The current data is important for population genetics and further studies in chickens and will serve as a valuable resource for investigating diversifying selection and candidate genes for selective breeding in chickens.Peer reviewedAnimal Scienc

    Development and Height Prediction of Fractured Water-Conducting Zone in Weakly Cemented Overburden: A Case Study of Tashidian Erjingtian Mine

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    To clarify the development and height of the fractured water-conducting zone of underground mines with weakly cemented overburden, the W8203 working face of the Tashidian Erjingtian Mine in Xinjiang, China, was selected to carry out a case study. Firstly, a physical analog model test was conducted to investigate the development law of the water-conducting fracture zone, followed by a numerical simulation via the PFC2D program. Afterward, a theoretical analysis based on the key stratum theory was carried out. The results demonstrated that there were one primary key stratum and three sub-key strata upon the W8203 working face. As verified by the physical analog tests, the water-conducting fracture developed to the bottom of the primary key stratum, and the height of the fractured water-conducting zone was 246.38 m. The numerical analysis suggests that the primary key stratum did not completely break and the fracture did not penetrate the stratum. Theoretical calculation indicated that the primary key stratum maintained stability in the structure without any breakage. The height of the fractured water-conducting zone is comprehensively determined to be 246.38 m, which is relatively close to the measured value (229.32 m). Based on the prediction method of key stratum position combined with the characteristics of weak cemented overburden, a method to predict the height of a water-conducting fracture zone suitable for weak cemented overburden was developed. The accuracy of this method was also verified through an in-depth comparison with field test results. Under the background of the “strategic westward shift” of coal resource exploration and development in China, the research results can provide theoretical and technical support for safe production in the Tashidian Mining Area and references for green and safe production in weakly cemented overburden mining areas in western China

    Effects of LaNiO₃ seed layer on the microstructure and electrical properties of ferroelectric BZT/PZT/BZT thin films

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    Ferroelectric multilayer films attract great attention for a wide variation of applications. The synergistic effect by combining different functional layers induces distinctive electrical properties. In this study, ferroelectric BaZr0.2Ti0.8O3/PbZr0.52Ti0.48O3/BaZr0.2Ti0.8O3 (BZT/PZT/BZT) multilayer thin films are designed and fabricated by using the magnetron sputtering method, and a LaNiO3 (LNO) seed layer is introduced. The microstructures and electrical properties of the BZT/PZT/BZT films with and without the LNO seed layer are systematically studied. The results show that the BZT/PZT/BZT/LNO thin film exhibits much lower surface roughness and a preferred (100)-orientation growth, with the growth template and tensile stress provided by the LNO layer. Moreover, an enhanced dielectric constant, decreased dielectric loss, and improved ferroelectric properties are achieved in BZT/PZT/BZT/LNO thin films. This work reveals that the seed layer can play an important role in improving the microstructure and properties of ferroelectric multilayer films.Published versionThe authors gratefully acknowledge support from the Outstanding Youth Fund of Heilongjiang Province (No. YQ2020E031). China Postdoctoral Science Foundation (No.2021T140166

    Carbon nanotubes and hexagonal boron nitride nanosheets co‐filled ethylene propylene diene monomer composites: Improved electrical property for cable accessory applications

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    Abstract Rubber‐based composites based on ethylene propylene diene monomer (EPDM) with excellent non‐linear electrical conductivity are preferred to serve as reinforced insulation in cable accessories, which can self‐adaptively regulate electric field distribution and avoid electric field concentration due to the non‐linear conductivity. The conductive carbon nanotubes (CNT) are filled into EPDM to improve the non‐linear conductivity, while the insulating hexagonal boron nitride nanosheets (h‐BN) are used to reconcile the electric breakdown strength. The results show that with the increase of CNT loading content, the non‐linear conductivity of CNT/h‐BN/EPDM composites becomes more prominent, accompanying the decrease of threshold field strength and increase of non‐linear coefficient. However, the electric breakdown strength of CNT/h‐BN/EPDM composites seriously deteriorates due to the increase of CNT content and temperature. By incorporating 10 wt.% h‐BN into the composites, the reduction percentage of breakdown strength can be significantly lowered, which is 19.95% of neat EPDM and 13.74% of CNT/h‐BN/EPDM composites at 70°C, respectively. The COMSOL Multiphysics simulation results demonstrate that using the CNT/h‐BN/EPDM composite as the reinforced insulation can eliminate the electric field concentration of the cable accessory as well as enable the cable accessory with good lightning shock resistance
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