在分析化学、生物工程、流量计量等领域,微量液体的粘度对工程分析和计算具有重要意义,微量液体粘度测量的方法也在逐渐发展完善。查阅资料发现,目前微量液体测量装置可用于测量粘度值低于150 m Pa·s的微量液体。为了解决微量液体...在分析化学、生物工程、流量计量等领域,微量液体的粘度对工程分析和计算具有重要意义,微量液体粘度测量的方法也在逐渐发展完善。查阅资料发现,目前微量液体测量装置可用于测量粘度值低于150 m Pa·s的微量液体。为了解决微量液体测量装置的粘度测量范围较小的问题,提出一种基于平行四边形柔性铰链的剪切运动的新型粘度测量方法,待测微量液体样本的体积仅为15μL。该方法使用固定在平行四边形柔性铰链上的刚性杆,将刚性杆的探针部分插入液体,在瞬态力的作用下,平行四边形柔性铰链做一维的阻尼振动,带动探针在液体中做剪切运动,由于液体粘滞力,系统的阻尼因数发生变化,液体粘度越大,阻尼因数越大。可以通过标定实验建立二者的关系,实现微量液体的粘度测量。结果表明,此微量液体粘度测量装置的测量范围扩大到了10 m Pa·s~750 m Pa·s,并且相对误差平均为5.8%。证明了该测量装置满足设计的需求,并且能够有效测量微量液体粘度。展开更多
Different from sculling forward of water striders with their hairy water-repellent legs, water spiders walked very quickly on water surfaces. By using a shadow method, the walking of water spiders had been studied. Th...Different from sculling forward of water striders with their hairy water-repellent legs, water spiders walked very quickly on water surfaces. By using a shadow method, the walking of water spiders had been studied. The three-dimensional trajectories and the supporting forces of water spider legs during walking forward were achieved. Results showed that the leg movement could be divided into three phases: slap, stroke, and retrieve. Employing an effective strategy to improving walking efficiency, the sculling legs supported most of its body weight while other legs were lifted to reduce the lateral water resistance, which was similar to the strategy of water striders. These findings could help guiding the design of water walking robots with high efficiency.展开更多
文摘在分析化学、生物工程、流量计量等领域,微量液体的粘度对工程分析和计算具有重要意义,微量液体粘度测量的方法也在逐渐发展完善。查阅资料发现,目前微量液体测量装置可用于测量粘度值低于150 m Pa·s的微量液体。为了解决微量液体测量装置的粘度测量范围较小的问题,提出一种基于平行四边形柔性铰链的剪切运动的新型粘度测量方法,待测微量液体样本的体积仅为15μL。该方法使用固定在平行四边形柔性铰链上的刚性杆,将刚性杆的探针部分插入液体,在瞬态力的作用下,平行四边形柔性铰链做一维的阻尼振动,带动探针在液体中做剪切运动,由于液体粘滞力,系统的阻尼因数发生变化,液体粘度越大,阻尼因数越大。可以通过标定实验建立二者的关系,实现微量液体的粘度测量。结果表明,此微量液体粘度测量装置的测量范围扩大到了10 m Pa·s~750 m Pa·s,并且相对误差平均为5.8%。证明了该测量装置满足设计的需求,并且能够有效测量微量液体粘度。
基金This work was financially supported by the National Natural Science Foundation of China(51805367)the Science Foundation of Tianjin(18JCQNJC04800,17JCYBJC19000,18JCZDJC31800).
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51323006 and 51425502)the Tribology Science Fund of State Key Laboratory of Tribology(Grant No.SKLTKF17B18)
文摘Different from sculling forward of water striders with their hairy water-repellent legs, water spiders walked very quickly on water surfaces. By using a shadow method, the walking of water spiders had been studied. The three-dimensional trajectories and the supporting forces of water spider legs during walking forward were achieved. Results showed that the leg movement could be divided into three phases: slap, stroke, and retrieve. Employing an effective strategy to improving walking efficiency, the sculling legs supported most of its body weight while other legs were lifted to reduce the lateral water resistance, which was similar to the strategy of water striders. These findings could help guiding the design of water walking robots with high efficiency.