Ultrasonic Measurements Near Transitions

加兰博士将应用实验方法，在他的 实验室，研究结构的形成和行为 玻璃和相称的阶段，重要的研究领域， 低温物理与化学 超声测量 提供了一个很好的方法，以提高基本的理解， 这些具有挑战性的问题，提供了一个重要的工具， 表征玻璃“冻结”温度， 监测兆赫频率范围内的预冻结动态。 此外，这些实验测量提供了数据， 这对于在纯物理中检验现代临界动力学理论至关重要。 流体，并指出新的发展方向， 理论 超声波研究也是有利的，因为静态和动态的超声研究都是有利的。 系统的动态响应可以由 声速和衰减的同时测量 波作为频率的函数。 将进行此类测量 作为温度和成分的函数，1）碱金属氰化物 结构玻璃，2）偶极铁电/反铁电结构玻璃 玻璃，和3）表现出不相称相的晶体。

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.