Nucleation Processes in Liquid Helium

w：\awards\awards96\num.doc 9703529 Maris 将进行实验研究以研究液氦中的成核过程。第一个项目是研究负压作用下氦液中气泡的成核。我们计划研究这个成核过程如何受到电子和量子化涡旋的影响。第二个项目的目标是在高于液体正常冻结压力的压力下检测固态氦的成核。第三个实验是在液氦和固体壁之间的界面上寻找气泡的成核。作为最后一个实验的一部分，我们将尝试测量液氦在负压下的状态方程。 气泡在液体中形成的方式在许多重要的技术应用中很重要。 这些包括喷墨打印机，船舶螺旋桨和液体泵。即使在清洁的液体中也会形成气泡，但通常会受到液体中杂质或固体颗粒的极大影响。研究液氦中的气泡是值得的，因为液氦比其他任何液体都要纯净，因此更容易进行不受杂质影响的实验。 *****

w:\awards\awards96\num.doc 9703529 Maris Experimental research will be performed to study nucleation processes in liquid helium. The first project is an investigation of the nucleation of bubbles in helium liquid which is subjected to a negative pressure. We plan to study how this nucleation process is influenced by the presence of electrons and quantized vortices. The goal of the second project is the detection of the nucleation of solid helium at pressures above the normal freezing pressure of the liquid. The third experiment is to look for the nucleation of bubbles at the interface between liquid helium and a solid wall. As part of this last experiment, we will attempt to measure the equation of state of liquid helium at negative pressure. %%% The way in which bubbles form in liquids is important in many technologically important applications. These include ink-jet printers, ship propellers, and liquid pumps. Bubble formation can occur even in clean liquids but is often greatly influenced by impurities or solid particles in the liquid. Studying bubbles in liquid helium is worthwhile because the liquid can be made much purer than any other liquid, and hence it is easier to perform experiments which are unaffected by the influence of impurities. *****