Pseudodendrothrips mori is a serious pest to mulberry trees and its infestation affects the qualitative and quantitative characteristics of mulberry leaves consumed by silkworm. The spatial distribution of mulberry th...Pseudodendrothrips mori is a serious pest to mulberry trees and its infestation affects the qualitative and quantitative characteristics of mulberry leaves consumed by silkworm. The spatial distribution of mulberry thrips within plant and orchard was assessed using Taylor＇s power law and Morisita＇s index of dispersion. The results showed that P.mori populations were localized in certain parts of the trees and fields. Distribution of thrips within plant showed that the larval instars were located on lower canopy （leaves 5-10 from top） of trees but adults preferred the upper canopy （leaves 1-5 from top）. The thrips density did not vary significantly among the leaf direction inside the trees. The thrips tended to be more accumulated on the trees located in East, South and North than in Center and West of orchard. The distributions of P.mori adults and larvae on the leaves were aggregated.展开更多
随着电力系统通信自动化技术的发展,各种信息采集系统得到广泛应用,这为分析电网故障的时空特性提供了有利条件。以H省电网500 k V输电网为例,探讨了5年间500 k V输电线路故障在较长时间段上的行为特性。首先在输电线路故障时间序列层面...随着电力系统通信自动化技术的发展,各种信息采集系统得到广泛应用,这为分析电网故障的时空特性提供了有利条件。以H省电网500 k V输电网为例,探讨了5年间500 k V输电线路故障在较长时间段上的行为特性。首先在输电线路故障时间序列层面上,统计分析输电线路故障发生的时间(单位:天)与同一时间点故障累计频次和累计概率之间的相互关系,采用Kolmogorov-Smirnov(K-S)法检验其分布的正态性,并根据R/S时序分析法计算出H省电网500 k V输电网5年间输电线路故障基于时序的Hurst指数,从而判断其在时间序列上具有长程相关性。然后,在空间层面上,统计分析5年期间H省电网每条500 k V输电线路故障次数与其发生频次和累计概率的关系,得出输电线路故障在空间上符合幂律分布特征。研究电网故障的时空分布特性为电网的风险管理和风险预测提供了辅助决策的依据。展开更多
文摘Pseudodendrothrips mori is a serious pest to mulberry trees and its infestation affects the qualitative and quantitative characteristics of mulberry leaves consumed by silkworm. The spatial distribution of mulberry thrips within plant and orchard was assessed using Taylor＇s power law and Morisita＇s index of dispersion. The results showed that P.mori populations were localized in certain parts of the trees and fields. Distribution of thrips within plant showed that the larval instars were located on lower canopy （leaves 5-10 from top） of trees but adults preferred the upper canopy （leaves 1-5 from top）. The thrips density did not vary significantly among the leaf direction inside the trees. The thrips tended to be more accumulated on the trees located in East, South and North than in Center and West of orchard. The distributions of P.mori adults and larvae on the leaves were aggregated.
文摘随着电力系统通信自动化技术的发展,各种信息采集系统得到广泛应用,这为分析电网故障的时空特性提供了有利条件。以H省电网500 k V输电网为例,探讨了5年间500 k V输电线路故障在较长时间段上的行为特性。首先在输电线路故障时间序列层面上,统计分析输电线路故障发生的时间(单位:天)与同一时间点故障累计频次和累计概率之间的相互关系,采用Kolmogorov-Smirnov(K-S)法检验其分布的正态性,并根据R/S时序分析法计算出H省电网500 k V输电网5年间输电线路故障基于时序的Hurst指数,从而判断其在时间序列上具有长程相关性。然后,在空间层面上,统计分析5年期间H省电网每条500 k V输电线路故障次数与其发生频次和累计概率的关系,得出输电线路故障在空间上符合幂律分布特征。研究电网故障的时空分布特性为电网的风险管理和风险预测提供了辅助决策的依据。
