Ultrasonically Levitated Granular Matter

超声波悬浮颗粒物质

基本信息

批准号：
1810390
负责人：
Heinrich Jaeger
金额：
$ 47.34万
依托单位：
University of Chicago
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-07-01 至 2021-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1810390&HistoricalAwards=false
关键词：
Ultrasonically Levitated Granular Matter

项目摘要

Non-Technical Abstract:The better understanding of granular matter, a class of materials comprised of large numbers of particles that collide and aggregate, is important for a wide range of industrial processes as well as natural phenomena, including the very beginning of planet formation from interstellar dust. The project introduces a new experimental platform, in which small particles are levitated acoustically, their arrangement can be manipulated under computer control, and their interactions can be measured with precision. The detailed investigation of such interactions among particles addresses many fundamental problems in physics and materials science, and improved knowledge about aggregate formation opens new opportunities for better control of industrial processes that involve the handling of fine particles. The project trains one graduate student, one postdoctoral scholar, and several undergraduate students, introduces them to forefront issues in materials research, and involves them in science outreach activities. Technical Abstract:The project focuses on sub-millimeter scale particles, which can easily become charged and as a result exhibit a rich interplay of short-range contact forces and longer-ranged electrostatic forces. To measure these forces with precision while providing a means for controlled particle manipulation, ultrasonic levitation generates a stable environment in which gravity is balanced by acoustic pressure so that minute particle-particle interactions become observable. A special aspect is the implementation of a sound pressure field that can be changed in real time under computer control. This enables experiments that previously have not been possible, such as the measurement of charge transfer during repeated particle-particle collisions. Suitable acoustic potentials also can produce lattices of particles of the same charge polarity, similar to Coulomb crystals in dusty plasmas. Importantly, ensembles of macroscopic particles are easily driven into the strongly interacting regime, where the interaction potential far exceeds the ambient thermal energy. Two thrusts of the project develop a programmable acoustic cavity for multi-particle trapping and manipulation, and investigate the collective behavior of systems comprised of large numbers of levitated particles.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要：对粒状物质的更好理解是一类由大量粒子碰撞和骨料组成的材料，对于广泛的工业过程以及自然现象至关重要，包括星际灰尘的行星形成的开始。该项目引入了一个新的实验平台，在该平台中，小粒子是通过声音悬浮的，可以在计算机控制下操纵其布置，并且可以精确地测量其相互作用。对粒子之间这种相互作用的详细研究解决了物理和材料科学中的许多基本问题，并且改善了对骨料形成的知识，为更好地控制涉及处理精细颗粒的工业过程提供了新的机会。该项目训练一名研究生，一名博士后学者和几位本科生，将他们介绍给材料研究中的最前沿问题，并参与科学外展活动。技术摘要：该项目着重于亚毫米尺度的颗粒，这些颗粒很容易被充电，因此表现出丰富的短距离接触力和较长的静电力的相互作用。为了精确地测量这些力，同时提供了一种用于受控的颗粒操纵的手段，超声悬浮会产生一个稳定的环境，在该环境中，重力通过声压平衡，因此可以观察到微小的粒子粒子相互作用。一个特殊的方面是实现声压场，该声音场可以在计算机控制下实时更改。这种实现了以前不可能的实验，例如在重复粒子碰撞期间电荷转移的测量。合适的声势还可以产生相同电荷极性的粒子的晶格，类似于灰尘等离子体中的库仑晶体。重要的是，宏观颗粒的集合很容易被驱动到强烈相互作用的方向上，在这种情况下，相互作用电位远远超过了环境热能。该项目的两个推力为多粒子捕获和操纵而开发了可编程的声学腔，并研究了由大量悬浮颗粒组成的系统的集体行为。该奖项反映了NSF的法定任务，并被认为是通过该基金会的知识分子和更广泛的影响来评估的，并被认为是值得的。