Ultrasonic Measurements Near Transitions

加兰德博士将运用在他的实验室中改进的实验方法，研究结构玻璃的形成和行为，以及与之相称的相，这是低温物理和化学的重要研究领域。超声波测量为表征玻璃“冻结”温度和监测兆赫频率范围内的冻结前动力学提供了一种极好的方法，从而增强了对这些挑战性问题的基本理解。此外，这些实验测量还为检验现代纯流体临界动力学理论提供了必要的数据，并为新理论的发展指明了方向。超声波研究也是有利的，因为系统的静态和动态响应都可以通过同时测量声波的速度和衰减作为频率的函数来确定。这样的测量将作为1)碱性氰化物结构玻璃、2)偶极铁/反铁电结构玻璃和3)呈现无公度相的晶体中的温度和组成的函数进行。

Dr. Garland will apply experimental methods, refined in his laboratory, to study in formation and behavior of structural glasses and the commensurate phases, important research areas in low temperature physics and chemistry. Ultrasonic measurements provide an excellent method to enhance the basic understanding of these challenging problems by providing an important tool for characterizing the glass "freezing" temperature and for monitoring prefreezing dynamics in the megahertz frequency range. In addition, these experimental measurements provide the data essential to testing modern theories of critical dynamics in pure fluids and to point the directions for the development of new theory. Ultrasonic studies are also advantageous since both the static and dynamic response of a system can be determined from simultaneous measurements of velocity and attenuation of acoustic waves as a function of frequency. Such measurements will be made as a function of temperature and composition in 1) alkali cyanide structural glasses, 2) dipolar ferro/antiferroelectric structural glasses, and 3) crystals exhibiting incommensurate phases.