The Microscopic Origin of Efficiency Droop in LEDs
11-20-17
Marco Bernardi, Assistant Professor of Applied Physics and Materials Science, and his colleagues’ semiconductor research has shown that the coupling between electrons and thermal vibrations may be sapping energy from Light-emitting diodes—or LEDs. "Our work shows for the first time that the ever-present interaction between electrons with lattice vibrations can, by itself, explain why excited electrons can leak out of the active layer and account for inefficiencies in GaN LEDs," Professor Bernardi says. [Caltech story]
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APhMS
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Marco Bernardi
Laser-Imaging Technology Brought into Focus
10-26-17
Lihong Wang, Bren Professor of Medical Engineering and Electrical Engineering, and colleagues have improved a technique for taking three-dimensional (3-D) microscopic images of tissue, allowing them to see inside living creatures with greater precision than before. "This gives us the ability to look through opaque materials and see what's inside," Professor Wang says. "It's like an extension of the human eye, like Superman's X-ray vision." [Caltech story]
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EE
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MedE
Lihong Wang
Studying Entropy in Metallic Glasses
10-10-17
Brent Fultz, Barbara and Stanley R. Rawn, Jr., Professor of Materials Science and Applied Physics, and colleagues have pinpointed that arrangement of atoms is the main source of an increase in entropy during the glass transition. One persistent mystery about metallic glasses occurs at the so-called "glass transition." A cold metallic glass is hard and brittle, but when it is heated past a certain point—the glass transition—it becomes soft. [Caltech story]
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Brent Fultz
MatSci
The Science of Sweat
09-29-17
Wei Gao, Assistant Professor of Medical Engineering, is interested in the future of personalized and precision medicine, and is engineering the next generation of wearable health monitors and nanomachines that could enable rapid and hyper-localized drug delivery and surgery. The sweatband health tracker he is developing is capable of studying health at a molecular level. By analyzing an individual’s sweat, the device can monitor dehydration levels as well as blood glucose levels in real time. [Caltech interview]
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MedE
Wei Gao
Training a Machine to Watch Soccer
08-25-17
Yisong Yue, Assistant Professor of Computing and Mathematical Sciences, and colleagues have developed an algorithm that can automatically recognize formations of teams—how they arrange themselves on the field—when analyzing player tracking data. The algorithm can also imitate players' behavior. "We're training the algorithm to understand soccer at the same level that a fan would. It's not just mindlessly watching faceless players move across a field; it's watching strikers and right midfielders and forwards arrange themselves in specific formations," says Professor Yue. [Caltech story]
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CMS
Yisong Yue