In this work, a series of Cu2O-Ag/ZnO, Cu2O/ZnO and Ag/ZnO nanocomposites with various compositions were prepared via a hydrothermal method followed by chemical modification, and their antibacterial performance was investigated in detail. X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy results confirmed that 31 nm Cu20 and 30 nm Ag nanoparticles are well-dispersed on 202 nm ZnO grains to form a Cu2O/ZnO and Ag/ZnO heterojunction, respectively. The bi-heterojuction structure in the Cu20-Ag/ZnO provided a synergistic effect on antibacterial activity, and the(Cu2O)0.04Ag0.06ZnO0.9nanocomposites showed the highest antimicrobial activity of all samples with minimum inhibitory concentration and minimum bactericidal concentration against Escherichia coli and Staphylococcus aureus as low to 31.25 μg/mL, 250μg/mL, 125μg/mL and 500μg/mL, respectively. This is the first report of the antibacterial activities of Cu2O and Ag co-modified ZnO nanocomposites.
弱阻尼低频振荡特性是保证系统安全稳定运行的重要基础。提出采用Ibrahim时域法(Ibrahim time domain,ITD)和随机减量法相结合的方法处理广域测量信号,实现电力系统振荡特性的系统化分析。在介绍方法基本原理的基础上,通过不同类型南方电网实测信号功率谱特征比较,建立类噪声信号基本概念,进而以36节点系统仿真信号和南方电网实测信号为例,应用上述方法提取典型信号中所包含的系统动态特征信息,实现电网低频振荡特征参数识别,为基于广域测量信号,全面、及时、准确地掌握互联电力系统动态特性奠定坚实基础。
