Pollution flashover is one of themajor insulation accidents that can occur inmodern power systems.If the local arc is not sufficiently elongated by the creepage distance,the flashover performance of the insulator will...Pollution flashover is one of themajor insulation accidents that can occur inmodern power systems.If the local arc is not sufficiently elongated by the creepage distance,the flashover performance of the insulator will decrease.The insulator structure and equivalent salt deposition density(ESDD)are the main factors affecting the arc path and length.To investigate the forms of arc paths under different insulator structures and their influence on flashover characteristics,a platformfor recording arc paths is established.This study presents amethod to identify the pattern and distribution of insulator arc paths based on the effect of initial arc on electric field distribution.The results show that there are two main types of local arc paths between umbrellas—the cling-surface arc and the air-jump arc.Moreover,the air-jump arc includes two types—the bridging arc and the gap arc.With the increase in umbrella spacing and ESDD,the probability of arc propagation along the surface increases.The use of the creepage distance can be improved by changing the creepage coefficient to increase the distance between umbrellas.This method has over 90%accuracy.This study is of great significance for improving insulator structure and reducing pollution flashover accidents.展开更多
Transgenesis, which inserts exogenous DNA into animal genomes, is a widely used technique. Traditionally, the constructs for transgenesis are generated by step-by-step subcloning of DNA fragments, which requires multi...Transgenesis, which inserts exogenous DNA into animal genomes, is a widely used technique. Traditionally, the constructs for transgenesis are generated by step-by-step subcloning of DNA fragments, which requires multiple steps depending on the construct complexity. To overcome the limitation, advanced tools such as Gateway cloning (Hartley et al., 2000;Kwan et al., 2007), In-Fusion cloning (Sleight et al., 2010), and Gibson assembly (Gibson et al., 2009) have been developed. However, due to their ligation characteristics, no systematic method for transgenesis has been developed. ‘Golden Gate’ cloning first appeared in 2008, which is a widely used DNA assembly method (Engler et al., 2008, 2009). Here, we take zebrafish transgenesis as an example and develop a standardized system called GoldenFish, which is based on Golden Gate cloning. It can customize transgenic constructs in one step and can be applied to multiple types of transgenesis such as one gene driven by one promoter, multiple genes driven by one promoter, and multiple genes respectively driven by multiple promoters, significantly reducing working time.展开更多
基金This work was supported by the National Natural Science Foundation of China(52007138)Chengdu Technology Innovation R&D Project(2022-YF05-00971-SN).
文摘Pollution flashover is one of themajor insulation accidents that can occur inmodern power systems.If the local arc is not sufficiently elongated by the creepage distance,the flashover performance of the insulator will decrease.The insulator structure and equivalent salt deposition density(ESDD)are the main factors affecting the arc path and length.To investigate the forms of arc paths under different insulator structures and their influence on flashover characteristics,a platformfor recording arc paths is established.This study presents amethod to identify the pattern and distribution of insulator arc paths based on the effect of initial arc on electric field distribution.The results show that there are two main types of local arc paths between umbrellas—the cling-surface arc and the air-jump arc.Moreover,the air-jump arc includes two types—the bridging arc and the gap arc.With the increase in umbrella spacing and ESDD,the probability of arc propagation along the surface increases.The use of the creepage distance can be improved by changing the creepage coefficient to increase the distance between umbrellas.This method has over 90%accuracy.This study is of great significance for improving insulator structure and reducing pollution flashover accidents.
基金supported by the National Natural Science Foundation of China(32270859,32000576,and32192400)the National Key R&D Program of China(2021YFA0805000)the Natural ScienceeFoundationofChongqing(cstc2020jcyj-msxmX0882).
文摘Transgenesis, which inserts exogenous DNA into animal genomes, is a widely used technique. Traditionally, the constructs for transgenesis are generated by step-by-step subcloning of DNA fragments, which requires multiple steps depending on the construct complexity. To overcome the limitation, advanced tools such as Gateway cloning (Hartley et al., 2000;Kwan et al., 2007), In-Fusion cloning (Sleight et al., 2010), and Gibson assembly (Gibson et al., 2009) have been developed. However, due to their ligation characteristics, no systematic method for transgenesis has been developed. ‘Golden Gate’ cloning first appeared in 2008, which is a widely used DNA assembly method (Engler et al., 2008, 2009). Here, we take zebrafish transgenesis as an example and develop a standardized system called GoldenFish, which is based on Golden Gate cloning. It can customize transgenic constructs in one step and can be applied to multiple types of transgenesis such as one gene driven by one promoter, multiple genes driven by one promoter, and multiple genes respectively driven by multiple promoters, significantly reducing working time.
