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book using terahertz radiation. The
team uses a standard terahertz camera
to emit ultrashort bursts of radiation at
a stack of papers. A built-in sensor then
detects and analyzes the radiation’s
reflections. The researchers’ algorithm
can determine the distance from the
camera to each of the top 20 pages in
a stack and correctly identify letters
printed on the first nine sheets.
To determine the distance to each
sheet, the camera’s sensors locate the
margins of the 20-µm-deep air pocket
between each page, and then calculate
the difference between the time radi-
ation is emitted toward, and received
back from, these boundaries—similar
to a submarine using sonar. The system
distinguishes between ink and blank
paper by reading how the different
chemicals absorb different radiation
frequencies. Finally, the algorithm fil-
ters out competing noise. In addition
to perusing rare books too fragile to flip
through, the system could be used to
analyze any materials organized in thin
SCOPING OUT BATTERY
PERFORMACE WITH X-RAYS
An x-ray microscopy technique
developed at the DOE’s Lawrence
Berkeley National Laboratory, Calif.,
improves scientists’ ability to image
nanoscale changes inside the lithi-
um-ion battery particles that make up
electrodes. The new method uses soft
x-rays to image micron-sized lithium
iron phosphate particles as they charge
and discharge in a liquid electrolyte,
chronicling the evolution of the parti-
cles’ chemical composition and reac-
tion rates in real-time. Among other
findings, researchers discovered that
when positively charged lithium ions
embed in the electrode’s surface during
charging, they rarely do so uniformly,
Xinghang Zhang, a professor in the
School of Materials Engineering at
Purdue University,
West Lafayette,
Ind., received a $450,000 grant from
the
DOE’s Office of Basic Energy
Sciences
for work on metal charac-
terization. Zhang will serve as the
primary investigator for a three-
year research project, “Deforma-
tion Mechanisms of Nanotwinned
Aluminum and Binary Aluminum
Alloys,” using transmission electron
microscopy to examine aluminum’s
atomic structure.
purdue.edu.
BRIEFS
The in-house service lab at
Nanomechanics Inc.,
Oak Ridge, Tenn.,
now offers nanoscale indentation and nanomechanical testing for re-
search and industrial applications, in addition to scratch testing, hard-
ness and modulus measurements, and property mapping. Analytical lab
services for small-scale mechanical testing are also available, including
nondestructive mechanical property measurements, testing consulting,
research collaboration, and nanoindentation testing reference materials.
nanomechanicsinc.com.
Artistic rendition of lithium-ion battery particles under illumination of a finely
focused x-ray beam. Courtesy of Stanford, Chueh Group.
especially as a battery ages—a phe-
nomenon that likely curbs battery per-
formance over time.
The imaging technique was imple-
mented at the Lab’s Advanced Light
Source, at two beamlines that offer
high-performance scanning transmis-
sion x-ray microscopy (STXM), in which
an extremely bright x-ray beam is
focused onto a small spot. Previously,
transmission
electron
microscopy
(TEM) has been used to study working
batteries at the nanoscale, but STXM
can image a larger field of view and
thicker materials than TEM, and it pro-
vides very high chemical specificity.
Researchers are now working on new
x-ray microscopes that would improve
the platform’s spatial resolution by a
factor of 10.
lbl.gov.
A TERAHERTZ LOOK INTO
A CLOSED BOOK
Researchers from Massachusetts
Institute of Technology, Cambridge,
and Georgia Tech, Atlanta, designed an
imaging system that can read a closed
TESTING | CHARACTERIZATION
Researchers at MIT and Georgia Tech are
designing an imaging system that can
read closed books. Courtesy of Barmak
Heshmat.