Dynamics of condensed matter systems

我的研究重点是微观结构的时间演化。由于微观结构取决于样品的历史，因此需要非平衡热力学来理解。材料的微观结构对其大部分物理和机械性能至关重要。不仅故障率，而且许多其他重要的性能，包括抗拉强度、化学反应性和矫顽力，都关键取决于这种形态。这些结构的典型长度尺度是微米。了解微观结构是如何产生的，如何表征它们以及它们如何随时间演变是物理学中一个重要的基本问题。无序和非平衡系统跨越材料范围，包括二元合金（用于喷气涡轮机的Ni_3Al）到定向凝固晶体（雪花）。在无序系统中，相干性和相关性的性质和作用仍未被完全理解。实时现场x射线测量，使用时间分辨衍射或x射线光子相关光谱，允许在类似于处理材料的条件下测量微观结构。因此，它们非常适合研究微观结构的时间演变。

My research concentrates on the time evolution of microstructures. Since the microstructure depends on the history of the sample it requires nonequilibrium thermodynamics for its understanding. The microstructure of a material is central to most of its physical and mechanical properties. Not only failure rates, but many other important properties including tensile strength, chemical reactivity and magnetic coercivity, depend crucially on this morphology. The typical length scales of these structures is micrometers. It is an important fundamental problem in physics to understand how microstructures arise, how to characterize them and how they evolve in time. Disordered and nonequilibrium systems span the range of materials including binary alloys (Ni_3Al used for jet turbines) to directionally solidifying crystals (snowflakes). The nature and role of coherence and correlations in disordered systems is still not fully understood. Real-time in-situ x-ray measurements, using either time resolved diffraction or x-ray photon correlation spectroscopy, allow measurements of the microstructure under conditions similar to the conditions used in processing the materials. They are thus ideally suited to study the time evolution of microstructure.