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02.08
Washington
Technology Digest
Compiled
By IEEE-USA Staff
The following is a recap of new
and notable developments in electrical
engineering and computer or information
technology emerging from the federal government
and its research partners at year end in 2007.
The synopses have been adapted from agency news
releases. Highlighted topics include:
“COMBINATORIAL’
APPROACH SQUASHES SOFTWARE BUGS FASTER, CHEAPER
A team of computer scientists
and mathematicians from the National Institute
of Standards and Technology (NIST) and the
University of Texas, Arlington is developing an
open-source tool that catches programming errors
by using an emerging approach called
“combinatorial testing.” The NIST-Texas tool,
described at a recent conference, could save
software developers significant time and money
when it is released next year.
Studying software crashes in a
variety of applications from medical devices to
Web browsers, NIST researchers obtained hard
evidence to support long-held conventional
wisdom: most software failures result from
simple events rather than complex ones.** Even
for Web browsers containing hundreds of
different variables, most failures were caused
by interactions between just two variables.
Nonetheless, in the applications that the
researchers studied, additional failures could
result from interactions of up to six variables.
Based on that insight, the NIST-Texas
team went beyond the popular practice of
“pairwise testing,” or exploring interactions
between only two variables at a time, and
designed a method for efficiently testing
different combinations of settings in up to at
least six interacting variables at a time. Their
technique resembles combinatorial chemistry in
which scientists screen multiple chemical
compounds simultaneously rather than one at a
time.
The new tool generates tests for
exploring interactions among the settings of
multiple variables in a given program. Compared
to most earlier combinatorial testing software,
which has typically focused on testing
interactions between just two variables, the
tool excels at quickly generating efficient
tests for 6-way interactions or more.
See: Y. Lei, R. Kacker, D. R.
Kuhn, V. Okun and J. Lawrence, IPOG: A general
strategy for t-way software testing, IEEE
International Conference on Engineering of
Computer-Based Systems March 26-29, 2007, pp
549-556, Tucson AZ, USA.
FIRST DIRECT
MEASUREMENT OF NANOSCALE DETAILS OF
PHOTOLITHOGRAPHY PROCESS
Scientists at the National
Institute of Standards and Technology (NIST)
have made the first direct measurements of the
infinitesimal expansion and collapse of thin
polymer films used in the manufacture of
advanced semiconductor devices. It’s a matter of
only a couple of nanometers, but it can be
enough to affect the performance of
next-generation chip manufacturing. The NIST
measurements, detailed in a new paper,* offer a
new insight into the complex chemistry that
enables the mass production of powerful new
integrated circuits.
The smallest critical features
in memory or processor chips include transistor
“gates.” In today’s most advanced chips, gate
length is about 45 nanometers, and the industry
is aiming for 32-nanometer gates. To build the
nearly one billion transistors in modern
microprocessors, manufacturers use
photolithography, the high-tech, nanoscale
version of printing technology. The
semiconductor wafer is coated with a thin film
of photoresist, a polymer-based formulation, and
exposed with a desired pattern using masks and
short wavelength light (193 nm). The light
changes the solubility of the exposed portions
of the resist, and a developer fluid is used to
wash the resist away, leaving the pattern which
is used for further processing.
Exactly what happens at the
interface between the exposed and unexposed
photoresist has become an important issue for
the design of 32-nanometer processes. Most of
the exposed areas of the photoresist swell
slightly and dissolve away when washed with the
developer. However this swelling can induce the
polymer formulation to separate (like oil and
water) and alter the unexposed portions of the
resist at the edges of the pattern, roughening
the edge. For a 32-nanometer feature,
manufacturers want to hold this roughness to at
most about two or three nanometers.
Industry models of the process
have assumed a fairly simple relationship in
which edge roughness in the exposed “latent”
image in the photoresist transfers directly to
the developed pattern, but the NIST measurements
reveal a much more complicated process. By
substituting deuterium-based heavy water in the
chemistry, the NIST team was able to use
neutrons to observe the entire process at a
nanometer scale. They found that at the edges of
exposed areas the photoresist components
interact to allow the developer to penetrate
several nanometers into the unexposed resist.
This interface region swells up and remains
swollen during the rinsing process, collapsing
when the surface is dried. The magnitude of the
swelling is significantly larger than the
molecules in the resist, and the end effect can
limit the ability of the photoresist to achieve
the needed edge resolution. On the plus side,
say the researchers, their measurements give new
insight into how the resist chemistry could be
modified to control the swelling to optimal
levels.
The research, funded by SEMATECH,
is part of a NIST-industry effort to better
understand the complex chemistry of photoresists
in order to meet the needs of next-generation
photolithography.
See: V.M. Prabhu, B.D. Vogt, S.
Kang , A. Rao , E.K. Lin and S.K. Satija. Direct
measurement of the spatial extent of the in
situ developed latent image by neutron
reflectivity. Journal of Vacuum Science and
Technology B, 25(6), 2514-2520 (2007).
NIST IMAGING
SYSTEM MAPS NANOMECHANICAL PROPERTIES
The National Institute of
Standards and Technology (NIST) has developed an
imaging system that quickly maps the mechanical
properties of materials — how stiff or stretchy
they are, for example — at scales on the order of
billionths of a meter. The new tool can be a
cost-effective way to design and characterize
mixed nanoscale materials such as composites or
thin-film structures. The NIST nanomechanical
mapper uses custom software and electronics to
process data acquired by a conventional atomic
force microscope (AFM), transforming the
microscope’s normal topographical maps of
surfaces into precise two-dimensional
representations of mechanical properties near
the surface. The images enable scientists to see
variations in elasticity, adhesion or friction,
which may vary in different materials even after
they are mixed together. The NIST system,
described fully for the first time in a new
paper,* can make an image in minutes whereas
competing systems might take an entire day.
See: A.B. Kos and D.C. Hurley.
Nanomechanical mapping with resonance tracking
scanned probe microscope. Measurement Science
and Technology 19 (2008) 015504.
ENERGY
DEPARTMENT FUNDS LARGE-SCALE CARBON
SEQUESTRATION PROJECT
Following closely on the heels
of three recent awards through the Department of
Energy’s (DOE) Regional Carbon Sequestration
Partnership Program, on December 18, DOE awarded
$66.7 million to the Midwest Geological
Sequestration Consortium (MGSC) for the
Department’s fourth large-scale carbon
sequestration project. The Partnership led by
the Illinois State Geological Survey will
conduct large volume tests in the Illinois Basin
to demonstrate the ability of a geologic
formation to safely, permanently, and
economically store more than one million tons of
carbon dioxide (CO2). Subject to annual
appropriations from Congress, this project
including the partnership’s cost share is
estimated to cost $84.3 million. Advancing
carbon sequestration is a key component of
comprehensive efforts to pursue clean coal
technology to meet current and future energy
needs and meet President Bush’s goal of reducing
greenhouse gas emissions intensity 18 percent by
2012.
For more information, see:
http://www.doe.gov/news/5781.htm
NASA TO TEST
LUNAR HABITAT IN ANTARTICA
NASA will use the cold, harsh,
isolated landscape of Antarctica to test one of
its concepts for astronaut housing on the moon.
The agency is sending a prototype inflatable
habitat to Antarctica to see how it stands up
during a year of use.
Agency officials viewed the
habitat in mid-November at ILC Dover in
Frederica, Del., as it was inflated one last
time before being packed and shipped to
Antarctica's McMurdo Station. NASA is partnering
on the project with the National Science
Foundation, Arlington, Va., which manages
McMurdo Station, and ILC Dover, the company that
manufactured the prototype structure. All three
organizations will share data from the 13-month
test, which runs from January 2008 to February
2009. An inflatable habitat is one of several
concepts being considered for astronaut housing
on the moon.
NASA's Constellation Program is
working to send humans back to the moon by 2020.
After initial sorties, the astronauts will set
up a lunar outpost for long-duration stays, and
they will need a place to live. The agency is
developing concepts for habitation modules that
provide protection for the astronauts and are
easy to transport to the lunar surface.
"To land one pound of supplies
on the lunar surface, it'll require us to launch
125 pounds of hardware and fuel to get it
there," Lockhart said. "So our habitation
concepts have to be lightweight as well as
durable. This prototype inflatable habitat can
be taken down and redeployed multiple times, and
it only takes four crew members a few hours to
set up, permitting exploration beyond the
initial landing area."
The structure looks something
like an inflatable backyard bounce house for
children, but it is far more sophisticated. It
is insulated and heated, has power and is
pressurized. It offers 384 square feet of living
space and has, at its highest point, an 8-foot
ceiling. During the test period, sensors will
allow engineers to monitor the habitat's
performance.
The National Science Foundation
also is interested in lighter,
easier-to-assemble habitats. It currently uses a
50-year-old design known as a Jamesway hut,
which is bulky and complex in comparison to the
habitat being tested. Modern variations on the
Jamesway, although lighter, are still rigid and
difficult to ship, with limited insulation.
During the test of the new inflatable habitat,
NSF will study improvements in packing,
transportation and set up, as well as power
consumption and damage tolerance for this newest
variation of the concept.
NASA DETAILS TOP
EXPLORATION AND DISCOVERY STORIES OF 2007
In a news release issued Dec.
17, NASA released its top ten exploration and
discovery stories of 2007. Stories highlighted
include construction of Constellation Program
systems for return to the Moon, launch of the
Phoenix Mars robotic lander, new human
spaceflight records, and continued expansion of
the International Space Station.
Among the highlights was the
news that NASA researchers designed and built a
new silicon carbide differential amplifier
integrated circuit chip that has exceeded 4,000
hours of continuous operation at 500 degrees
Celsius - a breakthrough that represents a
100-fold increase in what had been achieved
previously. Prior to this development, such
integrated circuit chips had operated at these
high temperatures for only a few hours or less
before degrading or failing. The extremely
durable transistors and packaging technologies
will enable highly functional but physically
small integrated circuitry to be used for
sensing and to control electronics within harsh
environments, such as hot sections of jet
engines as well as long-duration spacecraft.
For more information, see:
http://www.nasa.gov/home/hqnews/2007/dec/HQ_07278_Year-ender.html
ACCORDING TO
U.S. CENSUS BUREAU, THE DEMAND FOR DIGITAL IS
SKYROCKETING
Factory sales of MP3 players
will rise from $424 million in 2003 to nearly $6
billion in 2007, according to projected sales.
Additionally, sales of digital television sets
and monitors for the same period are estimated
to increase from $8.7 billion to $26.3 billion.
The transition in consumer
electronics from analog to digital format is
just one of the many changes taking place in
American life that can be tracked in the U.S.
Census Bureau’s Statistical Abstract of the
United States: 2008. Published since 1878, it is
the authoritative and comprehensive summary of
statistics on everything from the number of
public school teachers to hotel accommodations,
from online shipping to marital status.
Products are not the only things
going digital; the process for acquiring them is
as well. Of the $3.7 trillion in retail sales in
2005, $93 billion (2.5 percent) were recorded as
e-commerce sales (Table 1019).
In 2005, electronic shopping and
mail-order houses accounted for 70 percent ($65
billion) of e-commerce sales, most notably from
computer hardware (14 percent), clothing (12
percent), and drugs and beauty aids (10
percent). Motor vehicle and parts dealers made
up another 18 percent of e-commerce sales (Table
1019 and 1020).
Between 2004 and 2005, Internet
publishing and broadcasting operating revenue
increased by 19 percent. Revenue from online
advertising space increased by 29 percent (Table
1116). Meanwhile, the number of daily newspapers
continued to decline, from 1,611 in 1990 to
1,437 in 2006. Circulation fell from 62.3
million subscribers to 52.3 million (Table
1102).
For more information, see:
http://www.census.gov/Press-Release/www/releases/archives/miscellaneous/011095.html
NOAA, NASA
SELECT LOCKHEED FOR SATELLITE-BASED LIGHTNING
DETECTION EQUIPMENT
On Dec. 19, the Commerce
Department’s National Oceanic and Atmospheric
Administration (NOAA) and the National Space
Administration (NASA) announced that Lockheed
Martin Space Systems Company of Palo Alto,
Calif., has been selected for a $96.7 million
(including options) contract award to design and
develop a new instrument on the next generation
of weather satellites that will detect patterns
in lightning flashes that give forecasters an
early indicator of severe thunderstorms and
tornadoes.
For more information, see:
http://www.noaanews.noaa.gov/stories2007/20071219_contract.html
DOD ANNOUNCES
NEW MANUFACTURING TECHNOLOGY PROGRAM FOR 2008
The Department of Defense
announced its new Manufacturing Technology (ManTech)
Program for 2008 at the Defense Manufacturing
Conference in Las Vegas in early December. John
J. Kubricky, deputy under secretary of defense
for advanced systems and concepts, explained
that the Army, Navy and Air Force have
successfully managed their individual ManTech
programs for decades; this is the first year for
DoD's defense-wide program.
Beginning in the federal
government's fiscal 2008, the program expects to
fund investments that will mature ceramic matrix
composites manufacturing processes,
system-on-chip packaging technology and design
guidelines, and advanced manufacturing processes
for prosthetics for our wounded warriors. "Other
project candidates are being evaluated, and we
anticipate returns-on-investment that range from
6:1 to 12:1 in terms of procurement and
operating costs, improved operational
availability rates, and faster availability for
deployment," said Kubricky.
The defense-wide ManTech program
aims to mature cross-cutting manufacturing
processes in parallel with new and emerging
technologies that are inserted into DoD systems.
ManTech enables a cost-efficient and
collaborative development process that
concurrently retires cross-cutting manufacturing
risk with technology risk to enable
product-ready technology insertion. Equally
important, the program aligns research and
development investments with suitable levels of
technology maturity or calls for corrective
options in advance of Milestone B decisions.
"The ManTech processes that are
developed, demonstrated and deployed through
this program will be used to produce
increasingly complex defense systems so our
nation maintains superior equipment that is more
affordable to acquire, operate and maintain,"
added Kubricky. ManTech generally measures
results in decreased cycle time for production,
lower manufacturing costs, more predictable
performance, and improved reliability that
yields reductions in life-cycle-costs.
More information regarding the
Defense Manufacturing Conference can be found
at: http://www.dmc.utcdayton.com/ .
THE QUEST FOR A
NEW CLASS OF SUPERCONDUCTORS
Fifty years after the
Nobel-prize winning explanation of how
superconductors work, a research team from Los
Alamos National Laboratory, the University of
Edinburgh and Cambridge University are
suggesting another mechanism for the
still-mysterious phenomenon.
In a review published on Dec. 20
in Nature, researchers David Pines, Philippe
Monthoux and Gilbert Lonzarich posit that
superconductivity in certain materials can be
achieved absent the interaction of electrons
with vibrational motion of a material’s
structure.
The review, “Superconductivity
without phonons,” explores how materials, under
certain conditions, can become superconductors
in a non-traditional way. Superconductivity is a
phenomenon by which materials conduct
electricity without resistance, usually at
extremely cold temperatures around minus 424
degrees Fahrenheit (minus 253 degrees
Celsius) — the fantastically frigid point at which
hydrogen becomes a liquid. Superconductivity was
first discovered in 1911.
A newer class of materials that
become superconductors at temperatures closer to
the temperature of liquid nitrogen — minus 321
degrees Fahrenheit (minus 196 degrees
Celsius) — are known as “high-temperature
superconductors.”
A theory for conventional
low-temperature superconductors that was based
on an effective attractive interaction between
electrons was developed in 1957 by John Bardeen,
Leon Cooper and John Schrieffer. The
explanation, often called the BCS Theory, earned
the trio the Nobel Prize in Physics in 1972.
The net attraction between
electrons, which formed the basis for the BCS
theory, comes from their coupling to phonons,
the quantized vibrations of the crystal lattice
of a superconducting material; this coupling
leads to the formation of a macroscopically
occupied quantum state containing pairs of
electrons — a state that can flow without
encountering any resistance, that is, a
superconducting state.
However, according to Pines,
Monthoux and Lonzarich, electron attraction
leading to superconductivity can occur without
phonons in materials that are on the verge of
exhibiting magnetic order — in which electrons
align themselves in a regular pattern of
alternating spins.
Among the classes of materials
that appear capable of superconductivity without
phonons are the so-called heavy electron
superconductors that have been studied
extensively at Los Alamos since the early
1980’s, certain organic materials, and the
copper oxide materials that superconduct at up
to twice the temperature at which nitrogen
liquefies.
“If we ever find a material that
superconducts at room temperature — the ‘Holy
Grail’ of superconductivity — it will be within
this class of materials,” says Pines. “This
research shows you the lamp post under which to
look for new classes of superconducting
materials.”
For more information, see:
http://www.eurekalert.org/pub_releases/2007-12/danl-tqf122007.php
THERMAL
RESISTENT HYBRID SEMICONDUCTORS COULD LEAD TO
HARDIER ELECTRONICS AND OPTOELECTRONICS
Recently published research by
scientists at the U.S. Department of Energy's
National Renewable Energy Laboratory (NREL) and
Argonne National Laboratory, and academic
institutions has shed light on a semiconducting
material with zero thermal expansion (ZTE). The
research may play a role in the design of future
generations of electronics and optoelectronics
that can withstand a wide range of temperatures.
Traditional interests in ZTE
materials have largely been in areas such as
optics, heat-engine components and kitchenware.
ZTE materials with applications in
non-conventional areas such as electronics and
optoelectronics are rare; most are glasses,
which do not work well in electronics
applications. The hybrid inorganic-organic
semiconductor investigated in this work is a
multifunctional semiconductor that has
previously been shown to possess superior
electronic and optical properties. The work also
suggests an alternative route to designing
materials with any desired positive or negative
thermal expansion.
“It's a merger of inorganic and
organic materials,” said Zahirul Islam, a
physicist in Argonne's X-Ray Science Division,
“which form a fully coherent,
three-dimensionally ordered crystal. Normally
inorganic and organic materials don't work very
well together, but here they are working
together to display these remarkable
properties.”
The materials under study form alternating
organic and inorganic layers that work together
to produce these effects. One contracts while
the other expands, and the net effect is zero.
“This work suggests a novel
approach to design the thermal expansion — from
positive to negative, including zero — in a
nanoscopic scale by assembling nano-scale units
in an ordered manner,” said principal
investigator Yong Zhang of NREL. “The idea has
only been demonstrated for tuning thermal
expansion in one dimension and study was limited
to one or two materials. Next, we would like to
extend the idea to higher dimensions (i.e., ZTE
in more than one dimension), and explore more
inorganic-organic combinations.”
These hybrid materials hold
promise for high-efficiency semiconductor
lasers, ultrathin and flexible solar cells and
light-emitting and detecting devices. It is
possible to “dope” the materials (adding small
amounts of other compounds) to form transparent
conducting materials, Zhang said.
While chemical and thermal
stability are two major problems for most
hybrids, the hybrid nanostructures investigated
in this work are found to be exceptionally
stable in the air, even under the illumination
of an ultraviolet laser.
For more information, see:
http://www.anl.gov/Media_Center/News/2007/news071219.html
SANDIA
SUPERCOMPUTER OFFERS NEW EXPLANATION FOR
TUNGUSKA DISASTER
The stunning amount of forest
devastation at Tunguska a century ago in Siberia
may have been caused by an asteroid only a
fraction as large as previously published
estimates, according to new Sandia National
Laboratories supercomputer simulations.
“The asteroid that caused the
extensive damage was much smaller than we had
thought,” says Sandia principal investigator
Mark Boslough of the impact that occurred June
30, 1908. “That such a small object can do this
kind of destruction suggests that smaller
asteroids are something to consider. Their
smaller size indicates such collisions are not
as improbable as we had believed.”
Because smaller asteroids
approach Earth statistically more frequently
than larger ones, he says, “We should be making
more efforts at detecting the smaller ones than
we have till now.”
The new simulation — which more
closely matches the widely known facts of
destruction than earlier models — shows that the
center of mass of an asteroid exploding above
the ground is transported downward at speeds
faster than sound. It takes the form of a
high-temperature jet of expanding gas called a
fireball. This causes stronger blast waves and
thermal radiation pulses at the surface than
would be predicted by an explosion limited to
the height at which the blast was initiated.
NEW SOFTWARE TO
AID EARLY DETECTION OF INFECTIOUS DISEASE
OUTBREAKS
A newly released software
program will let health authorities at the site
of an infectious disease outbreak quickly
analyze data, speeding the detection of new
cases and the implementation of effective
interventions.
The program, called TranStat,
was developed by a team of epidemiologists and
computer scientists from the Models of
Infectious Disease Agent Study (MIDAS), an
international program supported by the National
Institutes of Health (NIH) to build
computational models for studying disease
spread.
“A main goal of MIDAS is to make
the models developed by the researchers
available to the public health community and
policymakers,” said Jeremy M. Berg, Ph.D.,
director of the National Institute of General
Medical Sciences, the NIH component that funds
MIDAS. “TranStat is a great example of how MIDAS
is providing tools to help communities prepare
for emerging infectious disease outbreaks.”
Available for free and
downloadable at http://www.midasmodels.org,
TranStat can be used by public health officials
to systematically enter and store infectious
disease data. These data include details about
the infected individuals, such as their sex,
age, and onset of symptoms; their close
contacts; and any interventions they might have
received. The program also prompts the field
personnel to enter details about exposed but
uninfected individuals. The system does not
collect names or other personally identifying
information.
For more information, see:
http://www.eurekalert.org/pub_releases/2007-12/niog-nst120607.php
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