锂硫电池作为高能量密度的二次电池存在硫的低导电性和多硫化物的穿梭效应等问题。通过制备高还原度的氧化石墨烯隔膜,并将其应用于锂硫电池。利用石墨烯片层形成的空间位阻和小介孔结构,可阻挡多硫化物的迁移以及其高导电性可减弱电池...锂硫电池作为高能量密度的二次电池存在硫的低导电性和多硫化物的穿梭效应等问题。通过制备高还原度的氧化石墨烯隔膜,并将其应用于锂硫电池。利用石墨烯片层形成的空间位阻和小介孔结构,可阻挡多硫化物的迁移以及其高导电性可减弱电池极化。在0.2 C下,采用高还原氧化石墨烯隔膜的锂硫电池初始比容量达到了1143.2 m Ah/g,经过100次循环后容量保持率为74.25%。此外,在2 C下仍有626.1 m Ah/g的比容量。表明高还原氧化石墨烯隔膜可以有效提升锂硫电池的电化学性能,体现出卓越的长循环稳定性和杰出的倍率性能。展开更多
In the early fault period of high-speed train systems, the interested characteristic signals are relatively weak and easily submerged in heavy noise. In order to solve this problem, a state-transition-algorithm (STA)-...In the early fault period of high-speed train systems, the interested characteristic signals are relatively weak and easily submerged in heavy noise. In order to solve this problem, a state-transition-algorithm (STA)-based adaptive stochastic resonance (SR) method is proposed, which provides an alternative solution to the problem that the traditional SR has fixed parameters or optimizes only a single parameter and ignores the interaction between parameters. To be specific, the frequency-shifted and re-scaling are firstly used to pre-process an actual large signal to meet the requirement of the adiabatic approximate small parameter. And then, the signal-to-noise ratio is used as the optimization target, and the STA-based adaptive SR is used to synchronously optimize the system parameters. Finally, the optimal extraction and frequency recovery of a weak characteristic signal from a broken rotor bar fault are realized. The proposed method is compared with the existing methods by the early broken rotor bar experiments of traction motor. Experiment results show that the proposed method is better than the other methods in extracting weak signals, and the validity of this method is verified.展开更多
The effect of functionalized graphene on the growth and development of Vicia faba L.was investigated by analyzing its impact on the composition and diversity of the microbial community in rhizosphere peat soil.Seedlin...The effect of functionalized graphene on the growth and development of Vicia faba L.was investigated by analyzing its impact on the composition and diversity of the microbial community in rhizosphere peat soil.Seedlings of V.faba planted in this peat soil were treated with either distilled water(CK)or 25 mg·L^(−1)(G25)of functionalized graphene solution.Results showed that the height and root length of V.faba seedlings in the G25 group were significantly larger than those in CK group.The microbial com-munity was analyzed by amplifying and sequencing the 16S rRNA gene V_(3)-V_(4) region of bacteria and internal transcribed spacer re-gion of fungi in rhizosphere soil using Illumina MiSeq technology.Alpha and beta diversity analysis indicated that functionalized graphene increased the richness and diversity of bacteria and fungi in the V.faba rhizosphere peat soil.The abundances of three ni-trogen cycling-related bacteria,Hydrogenophaga,Sphingomonas and Nitrosomonadaceae,were also altered after treatment with the functionalized graphene.The relative abundance of Basilicum,related to soil phosphorus solubilization,decreased in the fungal com-munity,while the relative abundance of Clonostachys and Dimorphospora,which exhibited strong biological control over numerous fungal plant pathogens,nematodes and insects,increased in the soil after functionalized graphene treatment.Redundancy analysis re-vealed that the potential of hydrogen(pH),organic matter,and total phosphorus contributed the most to the changes in bacterial and fungal community composition in the rhizosphere soil.Overall,our findings suggested that the addition of functionalized graphene altered the relative abundances of nitrogen and phosphorus cycling-related microorganisms in peat soil,promoting changes in the physicochemical properties of the soil and ultimately leading to the improved growth of V.faba plants.展开更多
文摘锂硫电池作为高能量密度的二次电池存在硫的低导电性和多硫化物的穿梭效应等问题。通过制备高还原度的氧化石墨烯隔膜,并将其应用于锂硫电池。利用石墨烯片层形成的空间位阻和小介孔结构,可阻挡多硫化物的迁移以及其高导电性可减弱电池极化。在0.2 C下,采用高还原氧化石墨烯隔膜的锂硫电池初始比容量达到了1143.2 m Ah/g,经过100次循环后容量保持率为74.25%。此外,在2 C下仍有626.1 m Ah/g的比容量。表明高还原氧化石墨烯隔膜可以有效提升锂硫电池的电化学性能,体现出卓越的长循环稳定性和杰出的倍率性能。
基金Projects(61490702,61773407,61803390,61751312)supported by the National Natural Science Foundation of ChinaProject(61725306)supported by the National Science Foundation for Distinguished Young Scholars of China+5 种基金Project(61621062)supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of ChinaProject(2017TP1002)supported by Hunan Provincial Key Laboratory,ChinaProject(6141A0202210)supported by the Program of the Joint Pre-research Foundation of the Chinese Ministry of EducationProject(61400030501)supported by the General Program of the Equipment Pre-research Field Foundation of ChinaProject(2016TP1023)supported by the Science and Technology Project in Hunan Province Hunan Science and Technology Agency of ChinaProject(2018FJ34)supported by the Science and Technology Project in Shaoyang Science and Technology Agency of China
文摘In the early fault period of high-speed train systems, the interested characteristic signals are relatively weak and easily submerged in heavy noise. In order to solve this problem, a state-transition-algorithm (STA)-based adaptive stochastic resonance (SR) method is proposed, which provides an alternative solution to the problem that the traditional SR has fixed parameters or optimizes only a single parameter and ignores the interaction between parameters. To be specific, the frequency-shifted and re-scaling are firstly used to pre-process an actual large signal to meet the requirement of the adiabatic approximate small parameter. And then, the signal-to-noise ratio is used as the optimization target, and the STA-based adaptive SR is used to synchronously optimize the system parameters. Finally, the optimal extraction and frequency recovery of a weak characteristic signal from a broken rotor bar fault are realized. The proposed method is compared with the existing methods by the early broken rotor bar experiments of traction motor. Experiment results show that the proposed method is better than the other methods in extracting weak signals, and the validity of this method is verified.
文摘The effect of functionalized graphene on the growth and development of Vicia faba L.was investigated by analyzing its impact on the composition and diversity of the microbial community in rhizosphere peat soil.Seedlings of V.faba planted in this peat soil were treated with either distilled water(CK)or 25 mg·L^(−1)(G25)of functionalized graphene solution.Results showed that the height and root length of V.faba seedlings in the G25 group were significantly larger than those in CK group.The microbial com-munity was analyzed by amplifying and sequencing the 16S rRNA gene V_(3)-V_(4) region of bacteria and internal transcribed spacer re-gion of fungi in rhizosphere soil using Illumina MiSeq technology.Alpha and beta diversity analysis indicated that functionalized graphene increased the richness and diversity of bacteria and fungi in the V.faba rhizosphere peat soil.The abundances of three ni-trogen cycling-related bacteria,Hydrogenophaga,Sphingomonas and Nitrosomonadaceae,were also altered after treatment with the functionalized graphene.The relative abundance of Basilicum,related to soil phosphorus solubilization,decreased in the fungal com-munity,while the relative abundance of Clonostachys and Dimorphospora,which exhibited strong biological control over numerous fungal plant pathogens,nematodes and insects,increased in the soil after functionalized graphene treatment.Redundancy analysis re-vealed that the potential of hydrogen(pH),organic matter,and total phosphorus contributed the most to the changes in bacterial and fungal community composition in the rhizosphere soil.Overall,our findings suggested that the addition of functionalized graphene altered the relative abundances of nitrogen and phosphorus cycling-related microorganisms in peat soil,promoting changes in the physicochemical properties of the soil and ultimately leading to the improved growth of V.faba plants.
