Investigating the effect of geocells on the erosion and deposition distribution of ephemeral gullies in the black soil area of Northeast China can provide a scientific basis for the allocation of soil and water conser...Investigating the effect of geocells on the erosion and deposition distribution of ephemeral gullies in the black soil area of Northeast China can provide a scientific basis for the allocation of soil and water conservation measures in ephemeral gullies.In this study,an artificial simulated confluence test and stereoscopic photogrammetry were used to analyze the distribution characteristics of erosion and deposition in ephemeral gullies protected by geocells and the effect of different confluence flows on the erosion process of ephemeral gullies.Results showed that when the confluence flow was larger,the effect of geocell was more evident,and the protection against ephemeral gully erosion was stronger.When the confluence flow rates were 0.6,1.8,2.4,and 3.0 m^(3)/h,ephemeral gully erosion decreased by 37.84%,26.09%,21.40%,and 35.45%.When the confluence flow rates were 2.4 and 3.0 m^(3)/h,the average sediment yield rate of the ephemeral gully was close to 2.14 kg/(m^(2)•min),and the protective effect of ephemeral gully erosion was enhanced.When the flow rate was higher,the surface fracture of the ephemeral gully was more serious.With an increase in confluence flow rate,the ratio of erosion to deposition increased gradually,the erosion area of ephemeral gullies was expanded,and erosion depth changed minimally.In conclusion,geocell measures changed erosion patterns by altering the rill erosion/deposition ratio,converting erosion from rill erosion to sheet erosion.展开更多
Particulates generated from electrode erosion in gas spark gap is inevitable and may initiate selfbreakdown behavior with high risk.Traditionally,this problem is addressed by empirical method qualitatively.To push thi...Particulates generated from electrode erosion in gas spark gap is inevitable and may initiate selfbreakdown behavior with high risk.Traditionally,this problem is addressed by empirical method qualitatively.To push this old problem forward,this paper conducts laser confocal microscopy measurement of eroded surface and a statistical method is introduced to obtain visualization of particulates distribution from electrode erosion after different shots.This method allows dense particulates to be classified with their heights in z direction and scattered figures of particulates within certain height range are obtained.Results indicate that the higher-than-10 μm particulates start to emerge after 200 discharge shots and particulates number has a waved radial distribution with a 0.5 mm wide deposition zone.Based on these quantitative results,the risk of reignition and field-distortion failure that are triggered by particulates can be assessed.展开更多
基金supported by the National Natural Science Foundation,China(41907047)the National Key Research and Development Program of China(2016YFE0202900)the Natural Science Foundation of Tianjin,China(18JCZDJC39600).
文摘Investigating the effect of geocells on the erosion and deposition distribution of ephemeral gullies in the black soil area of Northeast China can provide a scientific basis for the allocation of soil and water conservation measures in ephemeral gullies.In this study,an artificial simulated confluence test and stereoscopic photogrammetry were used to analyze the distribution characteristics of erosion and deposition in ephemeral gullies protected by geocells and the effect of different confluence flows on the erosion process of ephemeral gullies.Results showed that when the confluence flow was larger,the effect of geocell was more evident,and the protection against ephemeral gully erosion was stronger.When the confluence flow rates were 0.6,1.8,2.4,and 3.0 m^(3)/h,ephemeral gully erosion decreased by 37.84%,26.09%,21.40%,and 35.45%.When the confluence flow rates were 2.4 and 3.0 m^(3)/h,the average sediment yield rate of the ephemeral gully was close to 2.14 kg/(m^(2)•min),and the protective effect of ephemeral gully erosion was enhanced.When the flow rate was higher,the surface fracture of the ephemeral gully was more serious.With an increase in confluence flow rate,the ratio of erosion to deposition increased gradually,the erosion area of ephemeral gullies was expanded,and erosion depth changed minimally.In conclusion,geocell measures changed erosion patterns by altering the rill erosion/deposition ratio,converting erosion from rill erosion to sheet erosion.
基金supported by Science & Development Foundation of CAEP(Grant No.2015B0402085)
文摘Particulates generated from electrode erosion in gas spark gap is inevitable and may initiate selfbreakdown behavior with high risk.Traditionally,this problem is addressed by empirical method qualitatively.To push this old problem forward,this paper conducts laser confocal microscopy measurement of eroded surface and a statistical method is introduced to obtain visualization of particulates distribution from electrode erosion after different shots.This method allows dense particulates to be classified with their heights in z direction and scattered figures of particulates within certain height range are obtained.Results indicate that the higher-than-10 μm particulates start to emerge after 200 discharge shots and particulates number has a waved radial distribution with a 0.5 mm wide deposition zone.Based on these quantitative results,the risk of reignition and field-distortion failure that are triggered by particulates can be assessed.
