Mechanics meets chemistry
Biasing reaction pathways with mechanical force, Charles R. Hickenboth, Jeffrey S. Moore, Scott R. White, Nancy R. Sottos, Jerome Baudry & Scott R. Wilson, Nature 446, 423-427 (22 March 2007).
Education in China and in America
The New York Times Magazine this weekend featured a Harvard undergraduate student from China, and her work to shake up education in China. The article is long, but if you grew up in China, it should be a quick read, and fun. If you grew up in US or Europe, perhaps this is a helpful read, just to learn how other people live.
Mechanics of Precisely Controlled Thin Film Buckling on Elastomeric Substrate
Appl. Phys. Lett. 90, 133119 (2007)
Mechanics of Precisely Controlled Thin Film Buckling on Elastomeric Substrate
The Industry First Compact Reverse Pulse Plating Controller for R&D Applications in MEMS and Nanotechnology
Laguna Beach, CA March 31, 2007 -- Kebaili Corporation a leading California based high-tech company announced today the release of the CPG-500 Series, the industry first compact current pulse generator, specifically designed for electrodeposition applications, such as (direct current) DC plating, pulse plating, and periodic reverse pulse plating for a variety of applications in MEMS and nanotechnology.
Journal Club Theme of April 2007: Analytical Modeling of Biomolecules
The molecular building blocks of a cell include:
iMechanica get together at McMat 2007
Choose a channel featured in the header of iMechanica
Free Tags
Time: 5:45 pm - 7:00 pm, Wednesday, 6 June 2007.
Place: TCC 2.120 , UT Austin. (The room is reserved form 5:45 pm to 10:00 pm.)
Session moderators: Rui Huang and K. Ravi-Chander
Audience: Anyone interested in iMechanica. See a thread of discussion initiated by Pradeep Sharma. The event is free for all. So if you are local but are not attending McMat, you are still welcome to drop by.
Is it possible to obtain (without modeling) the fracture strength of defect-free nanotubes or nanowires by tensile loading?
What boundary conditions would allow failure to occur in the gauge length and not at or near the clamps? One is not allowed (in suggesting ways of overcoming stress concentation at the clamps) to create defects in the nanotube or nanowire, to configure the region where failure will occur. Thus, it is not possible (or is it?) to create an analog of dog-bone specimens by, e.g., milling away part of the nanowire with a focused ion beam, etc., because this creates defects in the nanowire.
Plastic Deformation Recovery in Freestanding Nanocrystalline Aluminum and Gold Thin Films
Science 30 March 2007:
Vol. 315. no. 5820, pp. 1831 - 1834
DOI: 10.1126/science.1137580
Jagannathan Rajagopalan, Jong H. Han, M. Taher A. Saif*
In nanocrystalline metals, lack of intragranular dislocation sources leads to plastic deformation mechanisms that substantially differ from those in coarse-grained metals. However, irrespective of grain size, plastic deformation is considered irrecoverable. We show experimentally that plastically deformed nanocrystalline aluminum and gold films with grain sizes of 65 nanometers and 50 nanometers, respectively, recovered a substantial fraction (50 to 100%) of plastic strain after unloading. This recoverywas time dependent and was expedited at higher temperatures. Furthermore, the stress-strain characteristics during the next loading remained almost unchanged when strain recovery was complete.These observations in two dissimilar face-centered cubic metals suggest that strain recovery might be characteristic of other metals with similar grain sizes and crystalline packing.
Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Self-healing polymers - an introduction
I'm now working on the preparation and characterization of self-healing polymers, a promising branch in materials science. The following is a general conception of this kind of materials system. (Pasted from our group website http://www.autonomic.uiuc.edu.) I may introduce some of my current work later.