Editor’s
Note: With this issue, we combine under one title two
NIST newsletters, NIST Update and NIST TechBeat.
We’ve made the change to help improve the timeliness of
our topics. Our goal is to include newsworthy topics tied to publication
of peer-reviewed papers, conference presentations, and other timely
“news hooks” as often as possible. We also will be
including photos and graphics whenever possible.
We hope you like the new look! Please let me know if you have
any comments or suggestions.
Gail Porter,
gail.porter@nist.gov
NIST TechBeat Editor
(301) 975-3392
copyright©
Geoffrey Wheeler |
|
Physicist
Deborah Jin and colleagues at JILA have reported an important
step toward creating a “super molecule,” a blend
of thousands of molecules acting in unison.
To
receive a high-resolution version of this image, contact
Gail Porter.
|
Ultracold
Experiments Pave Way for Super Molecule
A
team of researchers at JILA, a joint institute of the National
Institute of Standards and Technology (NIST) and the University
of Colorado at Boulder, report in the July 3 edition of Nature
an important step toward creating an ultracold “super
molecule,” a blend of thousands of molecules acting in
unison. Such a blend of molecules would provide physicists with
an excellent tool for studying molecular quantum mechanics and
superconductivity.
At
a temperature of only 150 nanoKelvin above absolute zero, the
team used lasers and a carefully tuned magnetic field to pair
potassium atoms belonging to a class of particles called fermions
into loosely joined molecules belonging to a class of particles
called bosons. Surprisingly, the researchers report the number
of molecules produced is very large with about a quarter million
(50 percent) of the atoms within the original cloud pairing
up.
"Our
experiments," notes NIST Physicist Deborah Jin, "produced
the lowest molecular binding energy that has been measured spectroscopically."”
In other words, the atom pairs forming each molecule are hanging
onto one another by their proverbial fingertips. The researchers
measured the energy holding the molecules together by breaking
the molecular bond with a relatively low-energy radio wave.
"This
work," Jin continues, "could help us understand the
basic physics behind superconductivity and especially high-temperature
superconductivity." Superconductivity is a property in
which electrons (a fermion particle) move through a metal with
no resistance. The experiments may lead to creation of fermion
superfluids made from gases that would be much easier to study
than solid superconductors. Creation of a "super atom"
(known as a Bose-Einstein condensate) earned another research
team at JILA the 2001 Nobel Prize in physics.
Media
Contact:
Fred
McGehan (Boulder), (303) 497-3246
NIST
Assists Hollywood With Digital Cinema Study
When
“Finding Nemo,” Disney/Pixar’s animated blockbuster
opened recently, only patrons in a few select theaters worldwide
could see it in its native format, ones and zeros. The movie’s
computer animation was created with digital technology, but
the vast majority of theaters are showing it on film because
they don't have digital projectors.
As more
films like “Nemo” are created, however, the technological
tide may be turning. Just as DVDs enable the display of sharper
images than videotapes, digital cinema should make it possible
to project sharper, brighter pictures than film. But are digital
images really better than film images?
To help
clarify the situation, scientists and engineers at the National
Institute of Standards and Technology (NIST) are helping the
film industry to measure the quality of images on the screen.
NIST is working with Digital Cinema Initiatives LLC (DCI), a
consortium of film studios that is creating a test bed to measure
and evaluate the performance of digital cinema systems, including
projectors. DCI plans to look at the results of human evaluation
and of scientific measurements to evaluate image quality. NIST
is providing technical expertise for the project via test patterns
and procedures that measure brightness, contrast, resolution
and other variables that influence image quality.
The results
could have implications for other fields, such as high-resolution
satellite imagery and telemedicine, where the quality of X-rays
and other images is critically important.
Media
Contact:
Phil
Bulman, (301) 975-5661
System
Helps Ensure Reliability Of Military Communications
The
Army, Navy and Air Force use thousands of miles of optical fibers
on ships, planes and land-based installations to transmit voice
and data. They needed a simple, effective and highly accurate
way to measure the amount of light delivered by these glass “wires”
at key points in the transmission system. Power degradation along
the network can cause communication failure.
Working with ILX Lightwave Corp. of Bozeman, Mont., the National
Institute of Standards and Technology (NIST) came up with a system
capable of world-class optical measurements with push-button convenience.
The system consists of a NIST-designed optical detector and an
optical multimeter—designed by ILX Lightwave—that
measures light emitted from a fiber over a wide range of wavelengths.
There are two versions of the novel detector—one using silicon-based
sensors and the other using germanium-based sensors. The sensors
connect directly to an optical fiber without any additional optics
and with barely measurable light loss. Measurement uncertainty
is half that of previous optical fiber power detectors. The system
is described in an upcoming issue of the journal Metrologia.
According to NIST engineer John Lehman, independent measurements
of the detector’s performance by NIST and its German counterpart,
PTB (Physikalisch-Technische Bundesanstalt), are in “excellent
agreement.” Another comparison will be made this summer
with NIST’s British counterpart, the National Physical Laboratory.
The new systems are now being shipped to military calibration
centers where they will be used to annually check the accuracy
of optical fiber power
systems utilized in the field.
Media
Contact:
Fred
McGehan (Boulder), (303) 497-3246
Tiny
Bubbles: New Tool in Chemical Sensing?
As
the old Hawaiian love song says, tiny bubbles really do make some
people feel fine. Chemists, that is. But there is no wine involved
this time, just water.
National Institute of Standards and Technology (NIST) chemists
reported in the June 24 online edition of Langmuir that
a process called microboiling shows promise for quick, simple
and inexpensive chemical sensing. The process involves the formation
of tiny vapor bubbles on a 200-nanometer-thick film of precious
metal immersed in water and heated rapidly. By coating the metal
microheater with a single layer of water-repelling molecules,
the scientists dramatically altered the microboiling behavior.
Bubbles formed more obviously and at lower temperatures, and the
water in immediate contact with the metal got much hotter.
"It's
astounding to me that we changed one functional group on the surface
of that microheater and saw a dramatic change in the boiling behavior,"
says Michael Tarlov, a co-author of the paper.
The finding means that changes in boiling behavior should be useful
for detecting specific substances. The water surrounding a microheater
designed to bond with DNA or proteins, for example, might boil
at a different temperature if the target molecules were attached
to the coating. A change can be measured in just 5 microseconds,
much faster than typical lab techniques. NIST scientists have
found that the technique can detect surfactants, such as those
used in detergents, and are studying its use in microfluidic (or
lab-on-a-chip) devices. The research also has other potential
spin-offs, such as the use of designer coatings to improve efficiency
in boilers and heat exchangers and the use of microheaters to
simplify chemical manufacturing.
Media
Contact:
Laura
Ost, (301) 975-4034
Dot,
Dot, Dot . . . How Quantum Dots Line Up
A
method that can be used to predict the growth of earthquake faults
also aids prediction of the tiniest of phenomena—how arrays
of “artificial atoms,” or quantum dots, assemble and
stack themselves on semiconductor materials, National Institute
of Standards and Technology (NIST) researchers report in the July
15 issue of Physical Review B.
The insight could aid development of more reliable methods for
fabricating lasers, sensors and other devices that exploit quantum
dots’ special electronic properties—the result of
confining electrons in the space of a few nanometers. The minuscule
structures already are the basis for some lasers. Yet, difficulties
in making quantum dots of uniform size and precisely positioning
them on a substrate remain formidable. These obstacles stand in
the way of an array of faster, more powerful electronic and photonic
devices that require only small inputs of energy to spring into
action.
NIST’s Bo Yang and Vinod Tewary borrowed a mathematical
concept that explains how cracks grow in a solid, such as the
Earth’s crust or an airplane wing. The concept, called the
elastic energy release rate, accounts for how energy is apportioned
as a crack advances. The scientists found that the rate also accounts
for how self-assembling quantum dots, which strain the system’s
lattice-like atomic geometry, will position and align themselves
among their neighbors—those next door and those living below.
For cube-shaped quantum dots, at least, the equation predicts
the most “energetically favorable” location for a
quantum dot. The NIST pair says their theory can be used, for
example, to predict the optimal depth for embedding quantum dots
that will be overlain by another array of dots.
Media
Contact:
Mark
Bello, (301) 975-3776
Grants
to Fund Development Of Novel Technologies
New
blade technology that could make energy generation by wind turbines
more efficient, virus-resistant tissues for skin grafts, a method
for operating a car’s devices through conversational speech,
and an automated Web-searching and data organizing software system
are among the novel technologies to be developed by the private
sector with support from 16 awards announced by the National Institute
of Standards and Technology’s (NIST) Advanced Technology
Program (ATP).
A
list of the latest ATP awards with links to project fact sheets
may be found at www.nist.gov/news.
For more detail on individual projects, contact the recipient
company or joint venture partnership as listed at the bottom of
the project fact sheet.
For background information on the ATP, including history, statistics,
program evaluations, success stories and descriptions of previous
awards, go to www.atp.nist.gov.
Media
Contact:
Michael
E. Newman, (301) 975-3025
Securing
Federal Information Systems: NIST has released the second
public draft of its Guide for the Security Certification and
Accreditation of Federal Information Systems, a set of procedures
designed to help federal agencies ensure that the nation’s
critical information infrastructure is well protected. The new
draft incorporates changes based on feedback from the public and
private sectors, as well as changes related to the Federal Information
Security Management Act (FISMA) of 2002. The new draft is at http://csrc.nist.gov/sec-cert.
