Populism in Western democracies is on the rise.What was once conf ined to outliers and extreme political parties is now tearing away into the whole political system.Inflammatory speeches and critics of so-called'f...Populism in Western democracies is on the rise.What was once conf ined to outliers and extreme political parties is now tearing away into the whole political system.Inflammatory speeches and critics of so-called'fake news'made by展开更多
The current research on noncircular hobbing mainly focuses on the linkage model and motion realization.However,the intermittent cutting characteristics of hobbing would increase uncertainties in the manufacturing proc...The current research on noncircular hobbing mainly focuses on the linkage model and motion realization.However,the intermittent cutting characteristics of hobbing would increase uncertainties in the manufacturing process.In this paper,a hobbing machining model with tool-shifting characteristics was proposed to solve the problems of cutting force fluctuation and inconsistency of tooth profile envelope accuracy at different positions of the pitch curve in noncircular gear hobbing.Based on the unit cutting force coefficient method,the undeformed chip volume generated by interrupted cutting was used to characterize the fluctuation trend of the hobbing force.The fluctuation characteristics of the cutting force generated by different hobbing models were compared and analyzed.Using the equivalent gear tooth and hob slotting numbers,an analysis model of the tooth profile envelope error of the noncircular gear was constructed.Subsequently,the tooth profile envelope errors at different positions of the pitch curve were compared and analyzed based on the constructed model.The transmission structure of the electronic gearbox was constructed based on the proposed hobbing model,and the hobbing experiment was conducted based on the selfdeveloped noncircular gear CNC hobbing system.This paper proposes a hobbing method that can effectively suppress the fluctuation of the peak and whole circumference cutting force and reduce the maximum envelope error of the whole circumference gear teeth.展开更多
In this Shi Jiazhuang Royal King Apparel Group fashion show and franchise recruitment event, Liu Lianhong, president of the association of clothing industry trade of Hebei province made his presence and delivered a ke...In this Shi Jiazhuang Royal King Apparel Group fashion show and franchise recruitment event, Liu Lianhong, president of the association of clothing industry trade of Hebei province made his presence and delivered a key speech involving the status quo of Hebei garment industry, opportunities and challenges it faces, practical solutions and expectation as well, which impressed all the present a lot. After the event l had a face to face interview with him:展开更多
文摘Populism in Western democracies is on the rise.What was once conf ined to outliers and extreme political parties is now tearing away into the whole political system.Inflammatory speeches and critics of so-called'fake news'made by
基金Supported by National Natural Science Foundation of China(Grant Nos.52075142 and U22B2084).
文摘The current research on noncircular hobbing mainly focuses on the linkage model and motion realization.However,the intermittent cutting characteristics of hobbing would increase uncertainties in the manufacturing process.In this paper,a hobbing machining model with tool-shifting characteristics was proposed to solve the problems of cutting force fluctuation and inconsistency of tooth profile envelope accuracy at different positions of the pitch curve in noncircular gear hobbing.Based on the unit cutting force coefficient method,the undeformed chip volume generated by interrupted cutting was used to characterize the fluctuation trend of the hobbing force.The fluctuation characteristics of the cutting force generated by different hobbing models were compared and analyzed.Using the equivalent gear tooth and hob slotting numbers,an analysis model of the tooth profile envelope error of the noncircular gear was constructed.Subsequently,the tooth profile envelope errors at different positions of the pitch curve were compared and analyzed based on the constructed model.The transmission structure of the electronic gearbox was constructed based on the proposed hobbing model,and the hobbing experiment was conducted based on the selfdeveloped noncircular gear CNC hobbing system.This paper proposes a hobbing method that can effectively suppress the fluctuation of the peak and whole circumference cutting force and reduce the maximum envelope error of the whole circumference gear teeth.
文摘In this Shi Jiazhuang Royal King Apparel Group fashion show and franchise recruitment event, Liu Lianhong, president of the association of clothing industry trade of Hebei province made his presence and delivered a key speech involving the status quo of Hebei garment industry, opportunities and challenges it faces, practical solutions and expectation as well, which impressed all the present a lot. After the event l had a face to face interview with him:
