Science Highlights 2004
Science highlights of research occuring at the APS.
Structure of new DNA enzyme family member found
Cornell University researchers, who are trying to understand how proteins evolve
and function by looking at their structural features, used the APS and the
Cornell High Energy Synchrotron Source to uncover the crystal structure of
a protein involved in making the building blocks of DNA correctly.
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New method studies living bacteria cells (Oct.
29)
Researchers at the U.S. Department
of Energy's Argonne National Laboratory have found a new way to study individual
living bacteria cells and analyze their chemistry. (Image © 2004
American Chemical Society)
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Superstructures add to superconducting mystery (Oct. 15)
The discovery of oxygen "superstructures" in cuprate materials by two independent teams of physicists could help shed new light on the origins of high-temperature superconductivity, which has been one of the biggest mysteries in physics for almost 20 years. The results, which back up theoretical predictions made almost 15 years ago, suggest that the "stripes" of charge found in some high-temperature superconductors might not be as closely related to the ability of these materials to carry currents without resistance as was previously thought.
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Dynamical Self-Assembly of Nanocrystal
Superlattices during Colloidal Droplet Evaporation by in situ Small Angle X-Ray
Scattering (Oct.
11)
The nucleation and growth kinetics
of highly ordered gold nanocrystal superlattices during the
evaporation of nanocrystal colloidal droplets was elucidated
by in situ time-resolved small-angle x-ray scattering experiments
carried out at sector 1 of the APS. (Image ©2004 The
American Physical Society)
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Visualising an unusual geometry
shift (Sept. 21)
A
paper by Philip Coppens et al. in the Royal Society of Chemistry
(RSC) Journal Chemical Communications is featured on the "RSC
Hot Papers Web Page."
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Are Films Ferroelectric? (Jun. 25)
Thin films of ferroelectric material for use in future "electronic" devices can be as thin as developers desire without loss of function according to a synchrotron x-ray study carried out by researchers using the BESSRC/XOR beamline 12-ID at the APS. The results show that a thin film of one particular ferroelectric material, lead titanate, is still stable even in a layer a mere 1.2 nanometers thin, three unit cell layers thick.
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X-rayed
Movie (Jun.
11)
A
research team using the Cornell High Energy Synchrotron Source and the
Complex Materials Consortium sector 9 beamline at the Advanced Photon
Source has produced the fastest movies ever made of electron motion.
Created by scattering x rays off of water, the movies show electrons
sloshing in water molecules, and each frame lasts just 4 attoseconds
(quintillionths of a second). The results, published in the 11 June PRL,
could let researchers "watch" chemical reactions even faster than those
viewable with today's "ultrafast" pulsed lasers.
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New X-ray Tool Reveals Details of Ferroelectric Switching (Jun.
9)
All
of our current information technology relies on devices
that process information as binary ones and zeroes. Ferroelectric
materials are of special interest to developers of the
next generation of such devices because they exhibit polarized
electronic states that can represent bits of information.
Moreover, these materials retain their polarization states
without consuming electrical power, making ferroelectrics
the subject of intense study for nonvolatile memory applications
in which data is stored even when the power is turned off.
One problem, however, is polarization fatigue; after a
number of cycles, the switchable polarization begins to
taper off, rendering the device unusable. Recently, a team
of researchers from the University of Wisconsin, Bell Laboratories,
and the University of Michigan used the x-ray synchrotron
at the Advanced Photon Source (APS) to study the micron-scale
details of polarization fatigue in ferroelectric oxides.
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