Bulletin of the American Physical Society
2006 8th Annual APS Northwest Section Meeting
Friday–Saturday, May 19–20, 2006; Tacoma, Washington
Session G3: Condensed Matter II |
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Chair: Patricia Mooney, Simon Fraser University and Janet Tate, Oregon State University Room: Wyatt 101 |
Saturday, May 20, 2006 2:00PM - 2:36PM |
G3.00001: A view of metals through the terahertz window Invited Speaker: As electrons move through a metal, interaction with their environment tends to slow them down, causing the Drude peak in the optical conductivity to become narrower. The resulting peak width is typically in the terahertz frequency range that sits between microwaves the far infrared, too fast for conventional electronics and too slow for conventional infrared spectroscopy. With femtosecond laser techniques, however, coherent, broadband terahertz radiation can now be generated and detected with exquisite sensitivity, providing a new window onto electronic interactions in metals. I will discuss the application of this technique to a variety of metallic systems, including elemental lead, the nearly magnetic oxide metal CaRuO$_3$, and CrV alloys that span the quantum phase transition from spin-density wave to paramagnetic metal.\footnote{M. A. Gilmore, S. Kamal, D. M. Broun, and J. S. Dodge, {\em Appl. Phys. Lett.} {\bf 88}, 141910 (2006).} [Preview Abstract] |
Saturday, May 20, 2006 2:36PM - 2:48PM |
G3.00002: Image-based Nanocrystallography in Two and Three Dimensions with Database Support Peter Moeck, Bjoern Seipel, Ruben Bjorge, Phil Fraundorf High-resolution transmission electron microscopy (HRTEM) and atomic resolution scanning TEM (STEM), when combined with tools for image-based nanocrystallography possess the capacity to derive the crystallographic phase and shape of nanocrystals. This paper introduces two such tools: lattice fringe fingerprinting in two dimensions (2D) for the identification of unknown nanocrystal phases and tilt protocol applications in three dimensions (3D) for the determination of the shape of nanocrystals. Both the Nano-Crystallography Database (NCD, http://nanocrystallography.research.pdx.edu) and the Crystallography Open Database (COD, http://crystallography.net) are discussed because the whole fingerprinting concept is only viable if there are comprehensive databases to support the identification of an unknown nanocrystal phase. [Preview Abstract] |
Saturday, May 20, 2006 2:48PM - 3:00PM |
G3.00003: Nanocrystal Phase Identification by Lattice Fringe Fingerprinting from High Resolution Transmission Electron Microscope Images Ruben Bjorge, Bjoern Seipel, Peter Moeck, Philip Fraundorf Lattice fringe fingerprinting is a novel and powerful method of identifying and characterizing nanocrystalline structures or materials based on images from direct space high-resolution transmission electron microscopy (HRTEM). We examine Fourier transformed HRTEM images of nanocrystals in certain orientations (i.e. lattice fringes and cross fringes) in order to obtain a lattice fringe fingerprint plot. Such plots are used to identify a crystalline nanoparticle by comparing the experimental data with data that are derived from a comprehensive database. A lattice fringe fingerprint plot is similar to a classical X-ray powder diffractogram, but an important advantage is that the intersection angles of lattice fringes give us additional information. When transmission electron microscope image acquisition and data interpretation are automated and connected to a comprehensive database (such as our Nano-Crystallography Database, http://nanocrystallography.research.pdx.edu/), fringe fingerprinting will be able to compete with powder X-ray diffraction in identifying unknown nanocrystals on a routine basis. [Preview Abstract] |
Saturday, May 20, 2006 3:00PM - 3:20PM |
G3.00004: BREAK
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Saturday, May 20, 2006 3:20PM - 3:32PM |
G3.00005: Emergence and Phase Transitions Arnold Sikkema Phase transitions are well defined in physics through concepts such as spontaneous symmetry breaking, order parameter, entropy, and critical exponents. But emergence --- also exhibiting whole-part relations (such as top-down influence), unpredictability, and insensitivity to microscopic detail --- is a loosely-defined concept being used in many disciplines, particularly in psychology, biology, philosophy, as well as in physics[1,2]. I will review the concepts of emergence as used in the various fields and consider the extent to which the methods of phase transitions can clarify the usefulness of the concept of emergence both within the discipline of physics and beyond.\\ \\ 1. Robert B. Laughlin, {\em A Different Universe: Reinventing Physics from the Bottom Down} (New York: Basic Books, 2005). \\ 2. George F.R. Ellis, ``Physics and the Real World'', {\em Physics Today}, vol.~58, no.~7 (July 2005) pp.~49-54. [Preview Abstract] |
Saturday, May 20, 2006 3:32PM - 3:44PM |
G3.00006: Modified Taylor-Couette Flow in Multiply-Waisted Hourglass Geometries Simulations based upon Reaction-Diffusion Models Thomas Olsen, Yu Hou, Adam Kowalski, Richard Wiener The Reaction-Diffusion model \footnote{H. Riecke and H.-G. Paap, Europhys. Lett. \textbf{14}, 1235 (1991).} predicted a period doubling cascade to chaos in a situation analagous Taylor- Couette flow with hourglass geometry. This cascade to chaos was discovered in the actual fluid flow experiments\footnote{Richard J. Wiener \textit{et al}, Phys. Rev. E \textbf{55}, 5489 (1997).}. We model Taylor-Couette flow in a cylindrical geometry with multiple waists of super-critical flow connected by regions of barely super-critical flow by corresponding Reaction-Diffusion models. We compare our results to the findings of an ongoing experimental program. [Preview Abstract] |
Saturday, May 20, 2006 3:44PM - 3:56PM |
G3.00007: Energy from Ocean Waves, River Currents, and Wind Shyamal Guha The earth we live in is surrounded by fluids, which are in perpetual motion. There is air in the atmosphere, water in lakes, oceans and rivers. The air and water around us form our natural environment. Much of the fluid medium is in constant motion. The kinetic energy of this moving fluid is astronomical in magnitude. Over the years, I considered methods of converting a fraction of the vast reserve of this kinetic energy into electro-mechanical energy. I conceived a few schemes of such conversion. The fluids whose kinetic energy can be converted into electro-mechanical energy are: ocean waters, river current and atmospheric air. In a book to be published in 2006, I have described different techniques of energy conversion. In the APS meeting, I plan to discuss some of these techniques. [Preview Abstract] |
Saturday, May 20, 2006 3:56PM - 4:08PM |
G3.00008: Open Access Internet Resources for Nano-Materials Physics Education Peter Moeck, Bjoern Seipel, Girish Upreti, Morgan Harvey, Will Garrick Because a great deal of nano-material science and engineering relies on crystalline materials, materials physicists have to provide their own specific contributions to the National Nanotechnology Initiative. Here we briefly review two freely accessible internet-based crystallographic databases, the Nano-Crystallography Database (http://nanocrystallography.research.pdx.edu) and the Crystallography Open Database (http://crystallography.net). Information on over 34,000 full structure determinations are stored in these two databases in the Crystallographic Information File format. The availability of such crystallographic data on the internet in a standardized format allows for all kinds of web-based crystallographic calculations and visualizations. Two examples of which that are dealt with in this paper are: interactive crystal structure visualizations in three dimensions and calculations of lattice-fringe fingerprints for the identification of unknown nanocrystals from their atomic-resolution transmission electron microscopy images. [Preview Abstract] |
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