The study on the deposition efficiency of pesticide droplets on soybean leaves can provide the basis for reducing pesticide quantity and increasing pesticide efficiency during the application of soybean plant protecti...The study on the deposition efficiency of pesticide droplets on soybean leaves can provide the basis for reducing pesticide quantity and increasing pesticide efficiency during the application of soybean plant protection machinery.The movement behavior of droplet impinges on the plant leaf surface is affected by many factors,among which the most important and the easiest to adjust are spray droplet size and impingement velocity.By changing the droplet size and impact velocity and using Fluent simulation software,the pesticide droplet hitting the soybean leaf surface was simulated and a test platform was established to verify the simulation results.The conclusions are as follows:The longitudinal roughness of soybean leaves is higher than the transverse roughness,the longitudinal pressure of soybean leaves is higher than the transverse pressure during the impact process,and the velocity of droplet spreading along the longitudinal is lower than that of spreading along the transverse;although soybean leaf surface has high adhesion,droplet losses still exist when droplet impact velocity is relatively high.The maximum spreading diameter of the droplet increases first and then decreases with the increase of impact velocity.At the same time,the maximum spreading diameter of droplet increases with the increase of particle size.The droplet deposition was best at 1.34 m/s impact velocity and 985μm particle size.This conclusion can provide optimal operation parameters for soybean plant protection operation which can be used to guide soybean plant protection operation,improve control effect,reduce quantity and increase efficiency.展开更多
The spread of Western economics in modern China is a content-rich historical event which has taken more than a century. A complete understanding of this event depends on the analysis and summary of its features. This ...The spread of Western economics in modern China is a content-rich historical event which has taken more than a century. A complete understanding of this event depends on the analysis and summary of its features. This paper suggests that the spread of Western economics in modern China exhibits five main features： openness, periodicity, applicability, localization and limitation. Openness reflects the active attitude of Chinese scholars to learning and propagating Western economics. Periodicity reflects the changes in its effectiveness and focus over time. Applicability reflects its goal of promoting the development of Chinese economics and providing policy applications for China＇s economic growth. Localization of Western economic theories in China follows the trend of selected introduction and modification according to local situations. And limitation is inevitable because of the many difficulties facing the spread of Western economics during early modern times. Furthermore, this spread has a profound impact on China which is embodied in its features： it promotes the establishment of Chinese modern economics, provides appropriate examples for the modernization and evolution of Chinese society, and promotes transformation of the traditional economic system in China.展开更多
基金This work was financially supported by China Agriculture Research System of MOF and MARA(Grant No.CARS-04-PS25)This work was also financially supported by the Innovation and Demonstration Sub-Project of Comprehensive Utilization Mode of Agricultural Facilities in Henan Tobacco Area Based on the Increase of Tobacco Farmers'Income(Grant No.2018410000270095).
文摘The study on the deposition efficiency of pesticide droplets on soybean leaves can provide the basis for reducing pesticide quantity and increasing pesticide efficiency during the application of soybean plant protection machinery.The movement behavior of droplet impinges on the plant leaf surface is affected by many factors,among which the most important and the easiest to adjust are spray droplet size and impingement velocity.By changing the droplet size and impact velocity and using Fluent simulation software,the pesticide droplet hitting the soybean leaf surface was simulated and a test platform was established to verify the simulation results.The conclusions are as follows:The longitudinal roughness of soybean leaves is higher than the transverse roughness,the longitudinal pressure of soybean leaves is higher than the transverse pressure during the impact process,and the velocity of droplet spreading along the longitudinal is lower than that of spreading along the transverse;although soybean leaf surface has high adhesion,droplet losses still exist when droplet impact velocity is relatively high.The maximum spreading diameter of the droplet increases first and then decreases with the increase of impact velocity.At the same time,the maximum spreading diameter of droplet increases with the increase of particle size.The droplet deposition was best at 1.34 m/s impact velocity and 985μm particle size.This conclusion can provide optimal operation parameters for soybean plant protection operation which can be used to guide soybean plant protection operation,improve control effect,reduce quantity and increase efficiency.
文摘The spread of Western economics in modern China is a content-rich historical event which has taken more than a century. A complete understanding of this event depends on the analysis and summary of its features. This paper suggests that the spread of Western economics in modern China exhibits five main features： openness, periodicity, applicability, localization and limitation. Openness reflects the active attitude of Chinese scholars to learning and propagating Western economics. Periodicity reflects the changes in its effectiveness and focus over time. Applicability reflects its goal of promoting the development of Chinese economics and providing policy applications for China＇s economic growth. Localization of Western economic theories in China follows the trend of selected introduction and modification according to local situations. And limitation is inevitable because of the many difficulties facing the spread of Western economics during early modern times. Furthermore, this spread has a profound impact on China which is embodied in its features： it promotes the establishment of Chinese modern economics, provides appropriate examples for the modernization and evolution of Chinese society, and promotes transformation of the traditional economic system in China.
