Molecular motors

Life implies movement. Most forms of movement in the living world are powered by tiny protein machines known as molecular motors. Among the best known are motors that use sophisticated intramolecular amplification mechanisms to take nanometre steps along protein tracks in the cytoplasm. These motors transport a wide variety of cargo, power cell locomotion, drive cell division and, when combined in large ensembles, allow organisms to move. Motor defects can lead to severe diseases or may even be lethal. Basic principles of motor design and mechanism have now been derived, and an understanding of their complex cellular roles is emerging.     

小功率步进电机控制器的设计

采用单片机AT89C51对步进电机进行控制,通过IO口输出的具有时序的方波作为步进电机的控制信号,信号经过芯片SI-7300驱动步进电机;用4X4的键盘来对电机的状态进行控制,PMM8731是步进电机脉冲分配器,SI-7300是高性能步进电机集成功率放大器．它们和单片机一起可构成一种高效电机控制驱动电路．作者介绍了PMM8713与SI-7300的功能,给出了由它们组成的功率驱动电路及其在步进电机上的应用方法．     

二步聚合法提高聚丙烯酰胺分子量的研究

本文研究了多功能团引发剂４，４’－偶氨二「４－氰基戊酰（对－二甲基氨基）苯胺」分步引发丙烯酰胺的聚合反应。