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UNCLASSIFIED
A Lighter Filling in Earth’s Core
The outer core of the Earth, whose composition until now
has been a mystery, may consist of an alloy of iron and
magnesium.
Researchers in the laboratory created high pressures to make
new alloys of iron and magnesium with the same sound
propagation properties as the earth’s core.
• This is a major step toward predicting earthquakes.
• This research will also be significant for high pressure
alloy manufacturing techniques.
J.-F. Lin et al., Science 308, 1892 (24 June 2005)
Funded by DOE BES & National Nuclear
Security Administration (Carnegie/DOE
Alliance Center), NSF, the State of Illinois,
and the W. M. Keck Foundation
N. Dubrovinskaia et al., Phys. Rev. Lett. 95, 245502
(9 December 2005)
Funded by DFG, Swedish Research Council
(VR), and the Swedish Foundation for
Strategic Research (SSF)
The Density of States of Iron at high temperatures (red curve)
is shifted toward lower energies, indicating a softening of the
lattice, which decreases the velocity of compression waves.
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Studies in Strain Mapping Help Reduce Fatigue in Materials
Studies conducted at the ORNL’s High-Temperature Materials Laboratory
are helping scientists better understand the overload phenomena during
fatigue. The user study was aimed at revealing the mesoscale explain
mesoscale? changes that retard crack growth rate following an
overload.
which can help in developing micro-mechanical modeling.
Computing? Industry/ Manufacturing applications?
Industries such as X (Car producers, NASA, semiconductor
manufacturers?) are interested in exactly what happens at the
molecular scale when materials break.
With this information, we could design better materials and
predict whether certain materials are sufficient in
particular applications.
Using neutron diffraction at the HFIR Neutron Residual
Stress Mapping Facility, users from the University of
Tennessee mapped the elastic/plastic strains in front of
Who would be interested in this research? the crack tip.
Is other industry participating?
Work funded by ???
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Optimizing Permanent Magnets
Permanent magnetic materials play central roles
in the conversion of mechanical energy to
electricity in alternators, generators and many
other products and technologies.
Researchers at APS have developed promising
ways to enhance magnets, opening new
performance possibilities in energy
conservation, miniaturization of magnetic
devices, and other applications.
D. Haskel et al., Phys. Rev. Lett. 95 (21), 217207 (2005).
Unit cell of Nd2Fe14B indicating the location of the two
unequal Nd crystal sites that are the focus of this study.
Funded by DOE
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Capturing Atomic Processes
Preliminary experiments at the SSRL using electron
bunches only quadrillionths of a second long have
illuminated the motions of atoms, including the
atoms of a microchip.
These experiments point toward the enormous possibilities
opened up in 2008, the start target for the Linac Coherent
Light Source, a machine that will generate light so bright
and fast that it will:
-- Discover and probe new states of matter
-- Understand chemical reactions and biological processes
Single shot image of x-ray diffracted intensity of an
InSb crystal. The ultrafast drop in intensity along the in real time
central region of the image results from intense laser -- Image biological materials at the atomic level
induced disordering (i.e. melting).
-- Image chemicals and material structure on the
Lindenberg et. al., Science 308, 392 (2005). nanoscale
Gaffney et. al., Phys. Rev. Lett., 95, 127501
(2005).
Funded by DOE and in collaboration with several universities and national laboratories
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Neutron Reflectivity Reveals Suspected Air Layer under
Water Drops on Lily Pads
• Dew drops roll off lily pads
because their surfaces are
hydrophobic (“water fearing”)
• An air layer has long-
suspected under such a drop
• Removal of dissolved gases
reduced the layer thickness;
aeration increased it -6
10
• Hydrophobic forces govern X-ray Air
Regular_D2O
Degassed D2O
protein folding, lipid 10
-7
Fit_Xray_Air
Fit_reg_D2O
Fit_degas_D2O
aggregation, and hence life
itself Water -8
10
• [Dhaval A. Doshi, Erik B. Watkins,
Jaroslaw Majewski, Jacob Israelachvilli, Air (10 Å)
PNAS] 10
-9
-10
10
Hydrophobic Polymer 0 0.05 0.1 0.15 0.2
-1
0.25 0.3 0.35
Q (Å )
Quartz
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Neutron protein crystallography solves several complex
biological structures.
• Data from xylose isomerase recorded
181,797 reflections allowing
researchers to map hydrogen.
• Xylose isomerase helps convert Bunick and Hanson, ORNL
sucrose to fructose in the body.
Human insulin data
using PCS user-
friendly display (left)
and a schematic of
PCS (below)
Protein Crystallography Station, PCS
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Metal-Organic Frameworks (MOFs): Advanced
Storage Materials for the US Hydrogen Economy
Future hydrogen and fuel cell technologies
depend critically on the discovery of novel
materials to store large amounts of hydrogen
under ambient conditions. Metal-organic MOF5-4D2
framework (MOF) compounds are nano-
porous materials that show promise for
hydrogen storage applications because of their
tunable pore size and functionality. x=0.165
Neutron powder diffraction and first-principles
calculations have allowed researchers to
determine the hydrogen adsorption sites and
binding energies in MOF5, the most widely
studied MOF material. These results not only
hold the key to optimizing MOF materials for Yildirim and Hartman, Phys. Rev.
hydrogen storage applications, but also Lett. 95, 215504 (2006).
suggest that MOFs can be used as templates to
create artificial interlinked hydrogen
nanocages with novel properties. UNCLASSIFIED
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New Methods to Determine Complex Structures of
Important, Disordered Proteins in, e.g., HIV
Recently, scientists at the NIST Center for Neutron Research (NCNR) have developed computer
algorithms that can generate and evaluate ensembles of protein structures in solution. The unique aspect
of this work is that these calculated structures are subsequently compared to experimental data on real
proteins using small-angle neutron scattering techniques to determine which structures match the data. In
collaboration with researchers at the National Cancer Institute, the NCNR scientists have applied these
new methods to determine the first full-length structures of the human immunodeficiency virus (HIV)
coat protein, called “Gag.”
Basic Structure of an HIV Gag Protein Structure Modeling
Immature Retrovirus Particle (A. Rein et al., J. Mol. Biol. - in preparation.)
Rg = 31Å 2
Calculation Data explore 0.01
MA 6
wm 1 mg/ml (Rg=35±1Å)
4
model 1 (Rg=31Å)
-1
model 2 (Rg=38Å)
I(Q) cm
2
0.001
6
4
NC
CA 2
0.0001
3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 2 3
0.01 0.1
-1
~200 Å Q (Å )
~1100 Å
UNCLASSIFIED Representative Gag Structures
Yeager et al., Proc. Nat. Acad. Sciences
31Å Rg 38Å
95, 7299 (1998).
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Neutron Reflectivity Measurements Help to
Develop Higher Density Magnetic Storage Devices
The discovery of Giant Magnetoresistance
(GMR) has led to the rapid development of
new, high-density magnetic storage devices.
These rely on the phenomenon known as
exchange bias, which is not fully understood.
A microscopic model of exchange bias may
be illuminated by probing the magnetization
changes and the field dependent switching of Pinned Layer
Depth (nm)
the individual magnetic layers that make up
these storage devices. This can be achieved Free Layer
using polarized neutron reflectivity (PNR)
-1100 G – First Cycle 18 G – First Cycle 1050 G – Second Cycle
measurements, which provide sub-nanometer
resolution of the depth-dependent vector
magnetization. By collecting PNR data at
several points along the hysteresis curve, as S. Moyerman et al., J. App. Phys. (2006)
shown in the figure at right, one can measure
changes in the magnetic properties of the free In collaboration with San Jose Research Center,
and pinned magnetic layers in a prototypical Hitachi Global Storage Technologies
computer hard drive read/write head. UNCLASSIFIED
