Water Mass Formation, Renewal and Exchange in the Arctic Ocean: Tritium/He, 180 and 14C Measurements on the Arctic 1991 Expedition

北冰洋水团的形成、更新和交换：1991 年北极探险中的氚/He、180 和 14C 测量

• 批准号: 9002890
• 负责人: William Zimmermann
• 金额: $ 19万
• 依托单位: University of Minnesota Saint Paul
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-08-01 至 1994-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9002890&HistoricalAwards=false
• 关键词: Water; Mass; Formation; Renewal; Exchange

This project consists of an experimental study of the first onset of dissipation in the flow of superfluid 4He through an orifice of micron or submicron dimensions as the rate of flow surpasses a critical threshold. Measurements will be made of the magnitude of the critical rate of flow and its dependence on temperature, pressure, and shape of orifice and of any statistical rounding of the onset as a function of temperature, in order to gain information about the fundamental processes involved, for which no satisfactory model now exists. Use will be made of a small mechanical resonator capable of resolving single-quantum-vortex events in the oscillatory flow of superfluid through an orifice that is fabricated by means of electron-beam lithography and ion- beam milling or reactive plasma etching. Studies will be made using both a single-hole configuration and a closed-loop configuration analogous to an rf-biased superconducting quantum interference device.

本项目包括超流体4He在通过微米或亚微米尺寸的孔口时，流速超过临界阈值时首次耗散的实验研究。为了获得所涉及的基本过程的信息，将测量临界流量的大小及其对温度、压力和孔板形状的依赖关系，以及对起点作为温度函数的任何统计舍入，目前还没有令人满意的模型。将使用一个小型机械谐振器，该谐振器能够解决超流体振荡流动中的单量子涡旋事件，该谐振器通过通过电子束光刻和离子束铣削或反应等离子体蚀刻制造的孔。研究将使用单孔配置和类似于rf偏置超导量子干涉装置的闭环配置进行。