Dynamics of condensed matter systems

我的研究主要集中在非平衡条件下形成的微观结构的时间演变，并在很大程度上基于X射线衍射技术的使用。这些微观结构是大多数材料的物理和机械性能的核心。不仅是失效率，而且许多其他重要的性能，包括抗拉强度、化学反应活性和磁矫直，都至关重要地依赖于这种形态。这些结构的典型长度尺度是微米。许多通常被称为“现代太空时代”的先进材料是通过仔细和复杂的加工技术来剪裁其微观结构来获得它们的性能的。此外，了解这种微结构是如何产生的以及如何表征它们是物理学中的一个重要的基本问题。这些无序和非平衡系统跨越了材料的范围，包括二元合金(用于喷气式涡轮机的Ni3Al)、定向凝固晶体(雪花)和软材料(塑料和橡胶)。这些系统中的一致性和相关性的本质仍然没有被完全理解。透射式电子显微镜和扫描探针显微镜等技术允许科学家研究这些系统，但实时原位X射线测量，即时间分辨散射，允许在类似于传统工艺的条件下测量微结构，因此非常适合这些研究。

My research concentrates primarily on the time evolution of microstructures formed under nonequilibrium conditions and is heavily based on the use of x-ray diffraction techniques.  Microstructures are central to the physical and mechanical properties of most materials.  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.  Many of the advanced materials often denoted as "modern space age" materials get their properties from tailoring their microstructure by careful and sophisticated processing techniques.  Furthermore, it is an important fundamental problem in physics to understand both how such microstructures arise and how to characterize them.  Disordered and nonequilibrium systems span the range of materials including binary alloys (Ni3Al used for jet turbines) to directionally solidifying crystals (snowflakes) and to soft materials (plastic and rubber).  The nature of coherence and correlations in these systems is still not fully understood. Techniques such as transmission electron microscopy and scanning probe microscopy allow scientists to study these systems, but real-time in-situ x-ray measurements, i.e.  time resolved scattering, allow measurements of the microstructure under conditions similar to conventional processing and therefore are ideally suited for these studies.