This research uses the 59th-70th national emergency early warning information release monthly report data of China to study the total number of emergency early warnings in 2021, the general situation of early warning ...This research uses the 59th-70th national emergency early warning information release monthly report data of China to study the total number of emergency early warnings in 2021, the general situation of early warning categories and regional distribution differences. The results show that: 1) there are 387,075 early warning information in China in 2021, and the early warning has obvious seasonality. 2) The issuance of early warnings is obviously related to the seasons, and the issuance of early warnings varies from month to month. The issuance of one kind of early warning can easily lead to the issuance of another kind of early warning, that is, the early warnings are closely related, and some specific disasters are easy to cause secondary disasters. 3) There are differences in the number of early warnings in each province. 4) The reason for the peak of early warnings in July and the large proportion of red early warnings in Henan Province is the sudden heavy rainstorm in Henan Province in July;the physical mechanism of this heavy rainstorm is sufficient water vapor, strong uplifting movement and stable situation and a long existence time.展开更多
In recent years, natural disasters in China have occurred frequently, especially large disasters such as earthquakes, floods and droughts, which have posed a serious threat to local public safety. In addition, the geo...In recent years, natural disasters in China have occurred frequently, especially large disasters such as earthquakes, floods and droughts, which have posed a serious threat to local public safety. In addition, the geological environment of local mountainous areas in China is complex and diverse, and climate change is large. Considering the dynamic coupling effect of rainfall conditions to stimulate geological disasters, this paper takes dynamic risk assessment technology as the guide, constructs a dynamic risk early warning model of geological disasters, establishes a prototype system, realizes dynamic risk assessment and emergency early warning of geological disasters at the regional level, and provides feasible technical support for targeted emergency disaster prevention. At the same time, the investigation and evaluation, mechanism research and monitoring and early warning related to the comprehensive prevention and control of geological disasters are important tasks that cannot be ignored, an important link in the emergency response system for geological disasters, and a key stage process to guide scientific disaster prevention. On the basis of exploring the mechanism and catastrophic effect of rainfall to stimulate landslides and mudslides, we will carry out in-depth research on disaster prevention countermeasures such as systematic engineering disposal, monitoring and early warning.展开更多
The monitoring of an accurate speed is crucial for driving safety,traffic efficiency,and environmental protection.However,the existing commercial wheel speed sensors require external power and costly maintenance.Tribo...The monitoring of an accurate speed is crucial for driving safety,traffic efficiency,and environmental protection.However,the existing commercial wheel speed sensors require external power and costly maintenance.Triboelectric nanogenerators(TENGs)offer significant advantages for self-powered sensing due to their sensitivity to environmental changes.Therefore,the present study has introduced a planetary gear structure that is known for its efficient transmission and smooth operation characteristics.A planetary gear-driven triboelectric speed sensor(PGTS)has also been designed.The structural optimization was performed by combining finite element analysis with experimental results.At a speed of 120 rpm,the open-circuit voltage and short-circuit current could reach 10 V and 0.2μA,respectively.Also,a peak power of 1.51μW was achieved at a load resistance of 30 MΩ.A high-precision revolution speed sensing algorithm was further developed for a real-time and accurate perception of the vehicle speed.The research results demonstrated that the PTGS was successfully integrated into the small-scale indoor tire-road testing platform,achieving a sensing accuracy of up to 99% in measuring the revolution speed.Furthermore,real vehicle tests were conducted using a Volkswagen Passat,and the fitting goodness-of-fit for the vehicle speed perception still reached 99%,with a minimum realtime fitting accuracy of 80.25%.Finally,a high-performance vehicle emergency monitoring system based on the vehicle slip rate level was proposed for monitoring abnormal vehicle behavior,which could promote a safety upgrade of the autonomous driving technology.展开更多
文摘This research uses the 59th-70th national emergency early warning information release monthly report data of China to study the total number of emergency early warnings in 2021, the general situation of early warning categories and regional distribution differences. The results show that: 1) there are 387,075 early warning information in China in 2021, and the early warning has obvious seasonality. 2) The issuance of early warnings is obviously related to the seasons, and the issuance of early warnings varies from month to month. The issuance of one kind of early warning can easily lead to the issuance of another kind of early warning, that is, the early warnings are closely related, and some specific disasters are easy to cause secondary disasters. 3) There are differences in the number of early warnings in each province. 4) The reason for the peak of early warnings in July and the large proportion of red early warnings in Henan Province is the sudden heavy rainstorm in Henan Province in July;the physical mechanism of this heavy rainstorm is sufficient water vapor, strong uplifting movement and stable situation and a long existence time.
文摘In recent years, natural disasters in China have occurred frequently, especially large disasters such as earthquakes, floods and droughts, which have posed a serious threat to local public safety. In addition, the geological environment of local mountainous areas in China is complex and diverse, and climate change is large. Considering the dynamic coupling effect of rainfall conditions to stimulate geological disasters, this paper takes dynamic risk assessment technology as the guide, constructs a dynamic risk early warning model of geological disasters, establishes a prototype system, realizes dynamic risk assessment and emergency early warning of geological disasters at the regional level, and provides feasible technical support for targeted emergency disaster prevention. At the same time, the investigation and evaluation, mechanism research and monitoring and early warning related to the comprehensive prevention and control of geological disasters are important tasks that cannot be ignored, an important link in the emergency response system for geological disasters, and a key stage process to guide scientific disaster prevention. On the basis of exploring the mechanism and catastrophic effect of rainfall to stimulate landslides and mudslides, we will carry out in-depth research on disaster prevention countermeasures such as systematic engineering disposal, monitoring and early warning.
基金supported by the National Key R&D Program of China(No.2023YFB2604600)the International Cooperation Project of Science and Technology Commission of Shanghai Municipality(No.22210710700)+1 种基金the National Natural Science Foundation of China(No.52278455)the Shuguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.21SG24).
文摘The monitoring of an accurate speed is crucial for driving safety,traffic efficiency,and environmental protection.However,the existing commercial wheel speed sensors require external power and costly maintenance.Triboelectric nanogenerators(TENGs)offer significant advantages for self-powered sensing due to their sensitivity to environmental changes.Therefore,the present study has introduced a planetary gear structure that is known for its efficient transmission and smooth operation characteristics.A planetary gear-driven triboelectric speed sensor(PGTS)has also been designed.The structural optimization was performed by combining finite element analysis with experimental results.At a speed of 120 rpm,the open-circuit voltage and short-circuit current could reach 10 V and 0.2μA,respectively.Also,a peak power of 1.51μW was achieved at a load resistance of 30 MΩ.A high-precision revolution speed sensing algorithm was further developed for a real-time and accurate perception of the vehicle speed.The research results demonstrated that the PTGS was successfully integrated into the small-scale indoor tire-road testing platform,achieving a sensing accuracy of up to 99% in measuring the revolution speed.Furthermore,real vehicle tests were conducted using a Volkswagen Passat,and the fitting goodness-of-fit for the vehicle speed perception still reached 99%,with a minimum realtime fitting accuracy of 80.25%.Finally,a high-performance vehicle emergency monitoring system based on the vehicle slip rate level was proposed for monitoring abnormal vehicle behavior,which could promote a safety upgrade of the autonomous driving technology.
