A novel approach for analyzing coupled vibrations between vehicles and bridges is presented,taking into account spatiotemporal effects and mechanical phenomena resulting fromvehicle braking.Efficient modeling and solu...A novel approach for analyzing coupled vibrations between vehicles and bridges is presented,taking into account spatiotemporal effects and mechanical phenomena resulting fromvehicle braking.Efficient modeling and solution of bridge vibrations induced by vehicle deceleration are realized using this method.The method’s validity and reliability are substantiated through numerical examples.A simply supported beam bridge with a corrugated steel web is taken as an example and the effects of parameters such as the initial vehicle speed,braking acceleration,braking location,and road surface roughness on the mid-span displacement and impact factor of the bridge are analyzed.The results show that vehicle braking significantly amplifies mid-span displacement and impact factor responses in comparison to uniform vehicular motion across the bridge.Notably,the influence of wheelto-bridge friction forces is of particular significance and cannot be overlooked.When the vehicle initiates braking near the middle of the span,both the mid-span displacement and impact factor of the bridge exhibit substantial increases,further escalating with higher braking acceleration.Under favorable road surface conditions,the midspan displacement and the impact factor during vehicle braking may exceed the design values stipulated by codes.It is important to note that road surface roughness exerts a more pronounced effect on the impact factor of the bridge in comparison to the effects of vehicle braking.展开更多
The article takes a simply supported prestressed concrete small box girder bridge project as an example for inspection and evaluation after a fire incident.This includes appearance detection,concrete color hardness de...The article takes a simply supported prestressed concrete small box girder bridge project as an example for inspection and evaluation after a fire incident.This includes appearance detection,concrete color hardness detection,concrete strength detection,concrete surface damage layer detection,reinforcement protective layer detection,and concrete carbonation detection.It is hoped that this analysis can be used as a reference for the detection and evaluation of future bridge projects with fire incidents to smoothen its subsequent repair and maintenance.展开更多
Brain-Machine Interface System Unveiled at Zhongguancun Forum The NeuCyber Array BMI System,a self-developed brain-machine interface(BMI)system from China,was unveiled at the opening ceremony of the 2024 Zhongguancun ...Brain-Machine Interface System Unveiled at Zhongguancun Forum The NeuCyber Array BMI System,a self-developed brain-machine interface(BMI)system from China,was unveiled at the opening ceremony of the 2024 Zhongguancun Forum(ZGC Forum)on April 25 in Beijing.At the forum,a video demonstration revealed a remarkable feat:a monkey,with its hands restrained and soft electrode filaments implanted in its brain,grasped a strawberry with an isolated robotic arm that was controlled by simply using its"thoughts."展开更多
"Comai is so beautiful,with such clean and tidy streets,and the sense of happiness and gain among the people is tremendous!It simply blew our mind,"a reporter from People's Daily exclaimed on his first v..."Comai is so beautiful,with such clean and tidy streets,and the sense of happiness and gain among the people is tremendous!It simply blew our mind,"a reporter from People's Daily exclaimed on his first visit to Comai.展开更多
基金supported by the Henan Provincial Science and Technology Research Project under Grant(152102310295).
文摘A novel approach for analyzing coupled vibrations between vehicles and bridges is presented,taking into account spatiotemporal effects and mechanical phenomena resulting fromvehicle braking.Efficient modeling and solution of bridge vibrations induced by vehicle deceleration are realized using this method.The method’s validity and reliability are substantiated through numerical examples.A simply supported beam bridge with a corrugated steel web is taken as an example and the effects of parameters such as the initial vehicle speed,braking acceleration,braking location,and road surface roughness on the mid-span displacement and impact factor of the bridge are analyzed.The results show that vehicle braking significantly amplifies mid-span displacement and impact factor responses in comparison to uniform vehicular motion across the bridge.Notably,the influence of wheelto-bridge friction forces is of particular significance and cannot be overlooked.When the vehicle initiates braking near the middle of the span,both the mid-span displacement and impact factor of the bridge exhibit substantial increases,further escalating with higher braking acceleration.Under favorable road surface conditions,the midspan displacement and the impact factor during vehicle braking may exceed the design values stipulated by codes.It is important to note that road surface roughness exerts a more pronounced effect on the impact factor of the bridge in comparison to the effects of vehicle braking.
文摘The article takes a simply supported prestressed concrete small box girder bridge project as an example for inspection and evaluation after a fire incident.This includes appearance detection,concrete color hardness detection,concrete strength detection,concrete surface damage layer detection,reinforcement protective layer detection,and concrete carbonation detection.It is hoped that this analysis can be used as a reference for the detection and evaluation of future bridge projects with fire incidents to smoothen its subsequent repair and maintenance.
文摘Brain-Machine Interface System Unveiled at Zhongguancun Forum The NeuCyber Array BMI System,a self-developed brain-machine interface(BMI)system from China,was unveiled at the opening ceremony of the 2024 Zhongguancun Forum(ZGC Forum)on April 25 in Beijing.At the forum,a video demonstration revealed a remarkable feat:a monkey,with its hands restrained and soft electrode filaments implanted in its brain,grasped a strawberry with an isolated robotic arm that was controlled by simply using its"thoughts."
文摘"Comai is so beautiful,with such clean and tidy streets,and the sense of happiness and gain among the people is tremendous!It simply blew our mind,"a reporter from People's Daily exclaimed on his first visit to Comai.
