论文部分内容阅读
2.1868年,伦,政府在街头竖司S。,925年.留学国的我国电机专家汝鼎发现绿灯亮时车拐晋对行人勺交通信号灯的诞生@贾肇曾
2. 1868, Lun, the government in the streets vertical Secretary S. , 925. Ru Ding, a motor expert from China who studied in China, found the birth of a traffic light on the pedestrian’s spoon bar when the green light was on. Jia Zhaozeng