Julia Greer, 32

Julia Greer has reinvented nanomechanics--the field that studies the mechanical properties, such as elasticity and strength, of materials at extremely small scales. These materials behave very differently from those at larger scales, and understanding the differences is essential for building reliable and durable ultrasmall devices.

Scientists have typically measured the mechanical properties of nanoscale materials by using a scanning electron microscope to capture images of an extremely sharp tip poking the surface of a thin film of the material. Greer, an assistant professor of materials science, greatly simplified and improved the process by introducing a technique that tests a nano pillar of the target material, compressing it and pulling on it in a single dimension instead of deforming an entire sheet.

Greer has used the method to confirm that metals and metal alloys are stronger at the nanoscale than at larger scales, something that researchers hadn't been able to prove before. The findings are providing engineers with the information they need to build nanoscale devices. --Kate Greene