中文摘要：

介绍了一种制备微纳米量级颗粒的流动聚焦技术，它的最基本特点是从毛细管流出的液体由高速运动气体驱动经小孔聚焦形成稳定的锥，锥顶端射出的微射流因不稳定性破碎成小颗粒。实验在自行设计的装置上完成，分析了流动聚焦技术中影响锥一射流以及颗粒形貌的因素，总结了过程中装置的结构参数以及气体压力降、液体流量和物性等流动参数对射流直径的影响。结果显示该技术制备的颗粒单分散性好，直径达到微米和亚微米量级，在工业方面有重大应用前景。

英文摘要：

A flow focusing （F-F） technique for producing droplets of diameter of mirco-or nano-meter is presented in this paper. It is characterized by the formation of a steady cone attached to a needle mouth in the core of a highly accelerating laminar gas stream through a hole. A mircojet issued from the cusp of the cone breaks up into droplets due to the capillary instability. The experiments have been carried out in the apparatus developed in USTC＇S lab. The factors influencing the characteristics of the cone-jet have been analyzed. The effects of the structure of the apparatus, the applied pressure drop, the flow rate and the properties of the liquids on the jet diameter at the hole exit have also been discussed. The results show that the droplets produced in the F-F are monodisperse with diameter of micrometer or sub-micrometer and the F-F has potential applications in many fields of industry.