ass日本风韵熟妇pics男人扒开女人屁屁桶到爽|扒开胸露出奶头亲吻视频|邻居少妇的诱惑|人人妻在线播放|日日摸夜夜摸狠狠摸婷婷|制服 丝袜 人妻|激情熟妇中文字幕|看黄色欧美特一级|日本av人妻系列|高潮对白av,丰满岳妇乱熟妇之荡,日本丰满熟妇乱又伦,日韩欧美一区二区三区在线

12.8h，f為1.79,。In order to manage farm machinery work system scientifically, the principles of ergonomics and a fatigue comprehensive evaluation method by heart rate and work time were proposed, and it was used for evaluating and analysis the tractor driver's fatigue in sowing work. The result showed that driving imported large power tractor in sowing work, the heart rate increase ratio is fairly low, and workload lies in light level, maximum acceptable work time (tmax) is between 14.2 h and 15.6 h, fatigue comprehensive assessment value f is between 1.21 and 1.48. While driving domestic Dongfanghong-1002-tractor, heart rate increase ratio is rather high, workload lies in normal level, tmax is 12.8h, and f is 1.79. In real operation, the working time of the driver is longer than maximum work time.