It is still a challenge to achieve large-area preparation of robust superhydrophobic surfaces with strong mechanical stability.Here,a simple and low-cost method to prepare robust decoupling superhydrophobic coatings o...It is still a challenge to achieve large-area preparation of robust superhydrophobic surfaces with strong mechanical stability.Here,a simple and low-cost method to prepare robust decoupling superhydrophobic coatings on aluminum(Al)alloys substrate has been presented.The superhydrophobicity and robustness of decoupling coatings are realized by structuring surfaces at two different length scales,with nanostructures for superhydrophobicity and microstructures for robustness.This prepared decoupling coating shows promising superhydrophobicity,with water contact angle(CA)of~158.4°and roll off angle(RA)of~3°.It also exhibits high repellency for impacting water droplets.Notably,the decoupling coating processes outstanding adhesion strength on the substrate after tape-peeling and cross-cut tests,also with promising wear resistantance after sandpaper abrasion and wear test.The friction coefficient of this decoupling coating is only~0.2.In addition,the robust decoupling superhydrophobic coating is applied to underwater buoyancy enhancement and fluid resistance reduction(drag reduction rate~30.09%).This decoupling superhydrophobic coating also displays promising self-cleaning and antifouling properties.Moreover,benefitting from the photocatalytic property of TiO2,this decoupling coating is also exploited for degrading organics to achieve seawater purification.This obtained decoupling superhydrophobic coating is expected to apply on other solids in marine fields,and the simple and eco-friendly method develops the potential practical application.展开更多
信号电涌保护器(surge protective device,SPD)对信号传输的影响,主要表现在暂态抑制二极管(transient voltage suppressor,TVS)的分布电容上,通过对平衡信号SPD和非平衡信号SPD电路的原理分析,将信号SPD等效为两端口网络,利用两端口网...信号电涌保护器(surge protective device,SPD)对信号传输的影响,主要表现在暂态抑制二极管(transient voltage suppressor,TVS)的分布电容上,通过对平衡信号SPD和非平衡信号SPD电路的原理分析,将信号SPD等效为两端口网络,利用两端口网络的T参数模型,采用理论与试验相结合的方法,试验结果得出:当TVS的分布电容值一定时,退耦电阻的阻值对幅频特性曲线-3 d B和-6 d B处的频率影响较小;退耦电阻的阻值一定时,随TVS分布电容值的增加,-3 d B和-6 d B处的频率均呈下降趋势。从信号传输的角度分析,频率越高,衰减越大,TVS的分布电容值在500~3 500 p F范围内,平衡传输时的幅频特性曲线-3 d B的频率范围为2~20 MHz,-6 d B的频率范围为5~25 MHz,非平衡传输时的幅频特性曲线-3 d B的频率范围为5~17 MHz,-6 d B的频率范围为6~20 MHz。这在防雷应用中有一定的参考价值。展开更多
基金supported by the National Natural Science Foundation of China(51905315)Shandong Provincial Natural Science Foundation(ZR2019BEM012)the Fundamental Research Funds for the Central Universities(20CX02316A).
文摘It is still a challenge to achieve large-area preparation of robust superhydrophobic surfaces with strong mechanical stability.Here,a simple and low-cost method to prepare robust decoupling superhydrophobic coatings on aluminum(Al)alloys substrate has been presented.The superhydrophobicity and robustness of decoupling coatings are realized by structuring surfaces at two different length scales,with nanostructures for superhydrophobicity and microstructures for robustness.This prepared decoupling coating shows promising superhydrophobicity,with water contact angle(CA)of~158.4°and roll off angle(RA)of~3°.It also exhibits high repellency for impacting water droplets.Notably,the decoupling coating processes outstanding adhesion strength on the substrate after tape-peeling and cross-cut tests,also with promising wear resistantance after sandpaper abrasion and wear test.The friction coefficient of this decoupling coating is only~0.2.In addition,the robust decoupling superhydrophobic coating is applied to underwater buoyancy enhancement and fluid resistance reduction(drag reduction rate~30.09%).This decoupling superhydrophobic coating also displays promising self-cleaning and antifouling properties.Moreover,benefitting from the photocatalytic property of TiO2,this decoupling coating is also exploited for degrading organics to achieve seawater purification.This obtained decoupling superhydrophobic coating is expected to apply on other solids in marine fields,and the simple and eco-friendly method develops the potential practical application.
文摘信号电涌保护器(surge protective device,SPD)对信号传输的影响,主要表现在暂态抑制二极管(transient voltage suppressor,TVS)的分布电容上,通过对平衡信号SPD和非平衡信号SPD电路的原理分析,将信号SPD等效为两端口网络,利用两端口网络的T参数模型,采用理论与试验相结合的方法,试验结果得出:当TVS的分布电容值一定时,退耦电阻的阻值对幅频特性曲线-3 d B和-6 d B处的频率影响较小;退耦电阻的阻值一定时,随TVS分布电容值的增加,-3 d B和-6 d B处的频率均呈下降趋势。从信号传输的角度分析,频率越高,衰减越大,TVS的分布电容值在500~3 500 p F范围内,平衡传输时的幅频特性曲线-3 d B的频率范围为2~20 MHz,-6 d B的频率范围为5~25 MHz,非平衡传输时的幅频特性曲线-3 d B的频率范围为5~17 MHz,-6 d B的频率范围为6~20 MHz。这在防雷应用中有一定的参考价值。
