Department of Applied Physics and Materials Science - Materials Science

News & Events

Highlights

Material's Spacing is Key to Brittle-to-ductile Transition

07-16-12

Julia R. Greer, her postdoctoral scholar Dr.Dongchan Jang, and colleagues have used experiments and atomistic simulations of nano-twinned metals (which have the unique combined effect of being strong and ductile) to decipher the specific role of the twin boundaries. They have found that it is the spacing between the twin boundaries that determines whether a material is brittle or ductile as opposed to the sample size, as would be expected. Greer states "this is probably the first study that truly isolated the twin boundaries by making samples which contained only twin boundaries, periodically spaced throughout the sample, and then tested them in tension. This understanding will help in the design of better structural materials and provide a certain amount of predictability in doing so, which has not been possible to date." [Nature Nanotechnology Article and Movies]

Tags: APhMS research highlights Julia Greer Dongchan Jang postdocs

Fueling Fundamental Research

10-13-11

To strengthen fundamental science and technology and foster transformational advances in renewable energies, the Dow Chemical Company and Caltech have established a $10 million partnership. Under the partnership, Dow will provide ongoing support for graduate student research through endowed fellowships which include five in energy science. The Resnick Sustainability Institute is receiving a significant portion of the funding in the agreement. Through the new Dow Chemical Company Bridge/CI2 Innovation Program, financial support will be used to further promising graduate and postdoc research that has the possibility of creating licensable technologies and start-ups. The graduate research fellowships in energy—renewable for up to two years—will help advance clean-energy goals. [Caltech Press Release]

Tags: APhMS energy Resnick Dow postdocs

Nano-mechanics of Carbon Nanotube Research Wins Art Competition

08-22-11

Siddhartha (Sid) Pathak, a W. M. Keck Institute for Space Studies (KISS) Postdoctoral Fellow in Material Science, has received the first prize in the NanoArt 2011 International Competition. The inspiration for Dr. Pathak's entry entitled "In-situ SEM deformation of CNT micro-pillars" is his research on nano-mechanics of carbon nanotubes.  As a KISS postdoc Dr. Pathak is working with  Professor Julia Greer on mechanical testing of carbon nanotubes at submicron length scales, with a particular emphasis towards space applications.  

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Tags: APhMS energy research highlights Julia Greer KISS Siddhartha Pathak postdocs

Engineers Solve Longstanding Problem in Photonic Chip Technology

08-04-11

Liang Feng, a Postdoctoral Scholar in Electrical Engineering who works with Professor Axel Scherer, has designed a new type of optical waveguide - a 0.8-micron-wide silicon device. The waveguide allows light to go in one direction but changes the mode of the light when it travels in the opposite direction. This new technique to isolate light signals on a silicon chip, solves a longstanding problem in engineering photonic chips. [Caltech Press Release]

Tags: APhMS EE energy research highlights Liang Feng Axel Scherer postdocs

One-way Transmission System for Sound Waves

07-26-11

Postdoctoral scholar, Georgios Theocharis, and GALCIT alumnus Nicholas Boechler; working with Professor Chiara Daraio, have created the first tunable acoustic diode- a device that allows acoustic information to travel only in one direction, at controllable frequencies. [Caltech Press Release]

Tags: APhMS energy research highlights Chiara Daraio GALCIT Georgios Theocharis Nicholas Boechler postdocs

Caltech Researchers Create "Sound Bullets"

04-22-10

Alessandro Spadoni, Postdoctoral Scholar, and Chiara Daraio, Assistant Professor of Aeronautics and Applied Physics, have built a nonlinear acoustic lens that produces highly focused, high-amplitude acoustic signals dubbed "sound bullets." The combination of the acoustic lens and sound bullets have "the potential to revolutionize applications from medical imaging and therapy to the nondestructive evaluation of materials and engineering systems," says Professor Daraio. [Caltech Press Release]

Tags: APhMS research highlights Chiara Daraio GALCIT health Alessandro Spadoni postdocs

Nanoscale Structures with Superior Mechanical Properties

02-09-10

Julia Greer, Assistant Professor of Materials Science and Mechanical Engineering, and Dongchan Jang, Postdoctoral Scholar, have developed a way to make some notoriously brittle materials ductile—yet stronger than ever—simply by reducing their size. Professor Greer describes, "We are entering a new era in materials science, where structural materials can be created not only by utilizing monolith structures, like ceramics and metals, but also by introducing 'architectural' features into them." [Caltech Press Release]

Tags: APhMS research highlights MCE Julia Greer Dongchan Jang postdocs

Oskar Painter and Colleagues Propose Quantum Entanglement for Motion of Microscopic Objects

12-21-09

Oskar Painter, Associate Professor of Applied Physics, along with colleagues Darrick Change, Postdoctoral Scholar at Institute for Quantum Information, and H. Jeff Kimble, William L. Valentine Professor and Professor of Physics have proposed a new paradigm that should allow scientists to observe quantum behavior in small mechanical systems. Their idea offers a new means of studying the nature of quantum superposition and entanglement in progressively larger and more complex systems. [Caltech Press Release]

Tags: APhMS research highlights Oskar Painter postdocs

Michael Elowitz and Avigdor Eldar Show How Evolution Can Allow for Large Developmental Leaps

07-20-09

Michael Elowitz, Associate Professor of Biology and Applied Physics; Bren Scholar, and Avigdor Eldar, Postdoctoral Scholar, show how evolution can allow for large developmental leaps. Most volutionary changes happen in tiny increments: an elephant grows a little larger, a giraffe's neck a little longer. Elowitz and Eldar's team have shown that such changes may at least sometimes be the result of noise, working alongside partial penetrance. Eldar, states "if you take a bunch of cells and grow them in exactly the same environment, they'll be identical twin brothers in terms of the genes they have, but they may still show substantial differences in their behavior." Elowitz adds that "noise—these random fluctuations of proteins in the cell—is not just a nuisance in this system; it's a key part of the process that allows genetically identical cells to do very different things." [Caltech Press Release]

Tags: APhMS health Michael Elowitz Avigdor Eldar postdocs

Michael Elowitz, Long Cai, and Chiraj Dalal Find Cells Coordinate Gene Activity with FM Bursts

10-17-08

How a cell achieves the coordinated control of a number of genes at the same time, a process that's necessary for it to regulate its own behavior and development, has long puzzled scientists. Michael Elowitz, assistant professor of biology and applied physics, along with postdoctoral research scholar Long Cai, and graduate student Chiraj Dalal, have discovered a surprising answer. Just as human engineers control devices ranging from dimmer switches to retrorockets using pulsed--or frequency modulated (FM)--signals, cells tune the expression of groups of genes using discrete bursts of activation. [Caltech Press Release]

Tags: APhMS research highlights health Michael Elowitz postdocs