Bubbles, Ions, and Vortices in Cryogenic Fluids

9500653威廉姆斯这个项目致力于低温流体的研究。主要项目是跨学科的，涉及物理、化学和光学科学的各个方面。这项研究涉及声致发光的新现象，特别是单泡声致发光。气泡被困在声谐振器中流体的中心，辐射出肉眼很容易看到的明亮的闪光。在这个过程中，能量密度可以增加1012倍，在1011，50皮秒的光脉冲与声周期同步到几个部分。该项目通过使用低温流体(氮气、Ar、Ne和氦)将声致发光实验扩展到低温。最初的氮气实验显示，与之前的涉及水介质的室温工作相比，光度有了惊人的增加。声致发光的机制尚不清楚，本项目将获得可能使声致发光的机制和理论得以发展的信息。其他子项目涉及吸附在多孔材料中的氦膜、声音在这些流体中的传播，以及对氦中超流体转变性质的理论研究。这个项目致力于低温流体的研究。主要项目是跨学科的，涉及物理、化学和光学科学的各个方面。这项研究涉及声致发光的新现象，特别是单泡声致发光。气泡被困在声谐振器中流体的中心，辐射出肉眼很容易看到的明亮的闪光。该项目通过使用低温流体(氮气、Ar、Ne和氦)将声致发光实验扩展到低温。最初的氮气实验显示，与之前的涉及水介质的室温工作相比，光度有了惊人的增加。声致发光的机制尚不清楚，本项目将获得可能使声致发光的机制和理论得以发展的信息。其他子项目涉及吸附在多孔材料中的氦膜、声音在这些流体中的传播，以及对氦中超流体转变性质的理论研究。***

9500653 Williams This project is devoted to the study of cryogenic fluids. The major project is interdisciplinary and involves aspects of physics, chemistry and optical science. The research deals with the new phenomena of sonoluminescence; particularly single bubble sonoluminescence. A vapor bubble, trapped at the center of fluid contained in an acoustic resonator, radiates bright flashes of light that are easily seen by the naked eye. In the process, energy densities can increase by a factor of 1012, and 50- picosecond light pulses are synchronized with the acoustic cycle to a few parts in 1011. This project extends the sonoluminescence experiments to low temperatures by employing cryogenic fluids (nitrogen, argon, neon, and helium). Initial experiments with nitrogen have revealed a spectacular increase in luminosity over prior room temperature work involving aqueous media. The mechanism of the sonoluminescence in not known, and this project will obtain information that may allow a mechanism and theory of the sonoluminescence to be developed. Additional subprojects deal with helium films adsorbed in porous materials, sound propagation in these fluids, and a theoretical study of the nature of the superfluid transition in helium. %%% This project is devoted to the study of cryogenic fluids. The major project is interdisciplinary and involves aspects of physics, chemistry and optical science. The research deals with the new phenomena of sonoluminescence; particularly single bubble sonoluminescence. A vapor bubble, trapped at the center of fluid contained in an acoustic resonator, radiates bright flashes of light that are easily seen by the naked eye. This project extends the sonoluminescence experiments to low temperatures by employing cryogenic fluids (nitrogen, argon, neon, and helium). Initial experiments with nitrogen have revealed a spectacular increase in luminosity over prior room temperature work involving aqueous media. The mechanism of the sonoluminescence in not known, and this project will obtain information that may allow a mechanism and theory of the sonoluminescence to be developed. Additional subprojects deal with helium films adsorbed in porous materials, sound propagation in these fluids, and a theoretical study of the nature of the superfluid transition in helium. ***