Leonardo da Vinci is usually credited with conducting the first systematic study of friction in the late 15th century, a subfield now known as tribology that deals with the dynamics of interacting surfaces in relative motion. Da Vinci's notebooks depict how he pulled rows of blocks using weights and pulleys, an approach that is still used in frictional studies today, as well as examining the friction produced in screw threads, wheels, and axles. The authors of this latest paper used an experimental setup similar to da Vinci's.
太行深处，河北阜平骆驼湾村，平整道路随山势蜿蜒，把小山村接入交通网。，详情可参考91视频
Алевтина Запольская (редактор отдела «Бывший СССР»)，推荐阅读旺商聊官方下载获取更多信息
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