NIST logo

Tech Beat - August 25, 2009

Tech Beat Archives

Submit an email address to receive news from NIST:

Editor: Michael Baum
Date created: December 29, 2010
Date Modified: December 29, 2010 
Contact: inquiries@nist.gov

Safer, Denser Acetylene Storage in an Organic Framework

The century-old challenge of transporting acetylene may have been solved in principle by a team of scientists working at the National Institute of Standards and Technology (NIST). A NIST research team has figured out* why a recently discovered material can safely store at low pressure up to 100 times as much of the volatile chemical as can be done with conventional methods.

closeup image of the HKUST-1 metal-organic framework

This closeup image of the HKUST-1 metal-organic framework (MOF), recently obtained by NIST scientists, reveals that copper atoms (green) are exposed to the open air within the MOF’s lattice-like structure. The exposed copper allows the MOF to safely store acetylene (magenta) up to 100 times more densely than current methods.

Credit: Liu, NIST
View hi-resolution image

The team has probed the atomic-level workings of a metal-organic framework (MOF), a lattice-like structure made of copper oxide and benzene, that soaks up acetylene like a sponge. Using tools at the NIST Center for Neutron Research (NCNR), the scientists have shown that exposed copper atoms within the lattice give the MOF its talent at storing acetylene. The findings, according to NCNR physicist Yun Liu, could be of use to the chemical industry in the future.

“This discovery could provide substantial savings in acetylene transportation costs,” says Liu, a member of the research team, which also included scientists from the University of Texas at San Antonio.

Acetylene, widely used in decades past for welding and illumination, is now also valuable as a starting point for synthesizing a range of chemicals used in plastics and explosives. In the United States alone, several hundred thousand tons of acetylene are produced every year, but its volatility renders it difficult to transport: It becomes dangerously explosive at about 30 psi (207 kilopascal), only about twice normal atmospheric pressure. To safely store acetylene, storage cylinders have to be filled with both porous material and liquid solvents such as acetone.

The research team used neutron powder diffraction and computer calculations at the NCNR to investigate an MOF called HKUST-1, which has a sponge-like interior in which copper atoms are exposed to the air. The analysis showed that the acetylene attaches to the exposed copper by virtue of weak electrical charges, allowing the MOF to store 201 cubic centimeters of acetylene per gram of lattice at ambient pressure—comparable to the amount of similar chemicals that can be contained within a high pressure storage cylinder.

Liu says the fundamental discovery could also help scientists better understand MOFs, which could be used to store other materials. “More than a thousand of these metal—organic frameworks have been created so far,” he says. “We hope our technique will turn out to be a good way to check such materials’ properties in advance.”

* S. Xiang, W. Zhou, J.M. Gallegos, Y. Liu, and B. Chen. Exceptionally High Acetylene Uptake in a Microporous Metal – Organic Framework With Open Metal Sites. Journal of the American Chemical Society, Aug. 11, 2009, DOI 10.1021/ja904782h.

Media Contact: Chad Boutin, boutin@nist.gov, 301-975-4261

back to top

Up-Scale: Frequency Converter Enables Ultra-High Sensitivity Infrared Spectrometry

In what may prove to be a major development for scientists in fields ranging from forensics to quantum communications, researchers at the National Institute of Standards and Technology (NIST) have developed a new, highly sensitive, low-cost technique for measuring light in the near-infrared range. The technique can measure the spectrum of the specific wavelengths of near infrared light used widely in telecommunications as well as the very weak infrared light at single-photon levels given off by fragile biomaterials and nanomaterials. They described their results in a recent issue of Optics Express.*

frequency converter equipment

A lithium niobate waveguide (bottom left) combines a pump laser and a near-infrared signal, “up-converting” the signal to a visible wavelength. Two prisms (right) separate the signal from the combined beam and send it to an avalanche photodiode detector (top left), which reads the up-converted signal.

Credit: NIST
View hi-resolution image

A single photon detector is the key device needed to build highly sensitive instruments for measuring spectra. For the past 30 years, scientists have made steady progress increasing the efficiency and sensitivity of visible and ultraviolet photon detectors while methods for detecting elusive single photons in the near-infrared (NIR) range have faltered. The methods presently in use are too static-laden, inefficient and slow, or depend on superconducting detectors, which require expensive, low-temperature operating environments. The NIST group, Lijun Ma, Oliver Slattery and Xiao Tang, wanted to develop a way to use existing detectors such as avalanche photodiode detectors (APD), which work very well for detecting visible light and are widely used, but are ineffective for the detection of NIR.

Their approach was to adapt a technique developed two years ago at NIST for quantum cryptography that “up converts” photons at one frequency to a higher frequency. The technique promotes the infrared photons up to the visible range using a strong, tunable laser. During the frequency conversion process, the narrow-band pump laser scans the infrared signal photons and converts only those that have the desired polarization and wavelength to visible light. Once converted to visible light, the signal photons are easily detected by commercially available APDs. According to Tang, the new system enables the measurement of spectra with sensitivity of more than 1,000 times that of common commercial optical spectral instruments.

“Our key achievement here was to reduce the noise, but our success would not have been possible without the many years of work by others in this field,” says Tang. “We hope that our discovery will open doors for researchers studying diseases, pharmaceuticals, secure communications and even solving crimes. We are very excited to make this technology available to the larger scientific community.”

* L. Ma, O. Slattery and X. Tang. Experimental study of high sensitivity infrared spectrometer with waveguide-based up-conversion detector. Optics Express. Vol. 17, No. 16. Aug. 3, 2009.

Media Contact: Mark Esser, mark.esser@nist.gov, 301-975-8735

back to top

Penetrating Insights: NIST Airframe Tests Help Ensure Better Shielding for Flight Instruments

Airline travelers are used to being instructed to turn off computers and cell phones during takeoffs and landings as a precaution against interfering with the plane's navigational equipment, but outside sources of high-energy interference can be even more dangerous. Recent tests by researchers at the National Institute of Standards and Technology (NIST) will provide much needed, independent data on how electromagnetic radiation penetrates aircraft, helping to ensure continued air travel safety.

photo of plane and testing equipment

Testing equipment being used by NIST scientists in recent research mapping radio frequency penetration of airframes, in this case a Boeing 737-200. The data from the tests provided valuable independent data on how electromagnetic radiation penetrates commercial aircraft, thereby helping improve safety.
Credit: NIST
View hi-resolution image

The Federal Aviation Administration (FAA) requires aircraft manufacturers to demonstrate that their aircraft have effective high intensity radiated field (HIRF) protection. The manufacturers conduct tests on their aircraft and provide those results to the FAA as part of the certification process. The tests are designed to show where and to what extent electromagnetic radiation, across a wide spectrum of frequencies, penetrates a given craft’s airframe. This information is important in determining if and where shielding is needed to protect vital electronic instrumentation from malfunction or damage while flying through ground-based radar beams, for example.

This effort was undertaken to assist the FAA with HIRF measurement procedures and data processing methodologies. The FAA has struggled with data sets provided by HIRF testers because they use a wide range of measurement/data processing techniques that are not standardized.

For an independent analysis of the situation, a NIST team recently performed HIRF tests on three representative aircraft to give FAA officials a frame of reference for the procedures and data reduction techniques used for typical low-level airframe HIRF attenuation/shielding tests. Having this information will help the FAA ensure that commercial aircraft are indeed meeting minimum shielding requirements and, ultimately, make the safety of tested aircraft more transparent. “This will get everyone on the same page,” says Chriss Grosvenor, a NIST electronics engineer. “The FAA and aircraft manufacturers now have a lot of unbiased data they can look at, and our method is just another method to obtain that information.”

The three aircraft chosen for the representative tests were a Boeing 737-200 and a Bombardier Global 5000 business jet, both owned by the FAA, and a Beechcraft Premier IA carbon-fiber composite business jet, owned by the Hawker-Beechcraft company. By measuring all three aircraft and comparing the results, NIST was able to provide a guide for the optimization of HIRF testing standards for the EMC aircraft manufacturing community. The tests were conducted over a two-year period using a commercial measurement system that incorporates NIST-developed ultra-wideband antennas, a network analyzer and an optical fiber link to obtain high-resolution measurements from the megahertz to gigahertz range. NIST-developed special software extends the number of frequencies to any desired value using a variable number of bands.

The findings of these tests were published last year* and were presented last week at the IEEE EMC Society Symposium on Electromagnetic Compatibility in Austin, Texas.

* C. Grosvenor, D. Camell, G. Koepke, D. Novotny and R.T. Johnk. Electromagnetic airframe penetration measurements. Paper presented at the 2009 IEEE International Symposium on Electromagnetic Compatibility, Austin, Texas, Aug. 17-21, 2009.

Media Contact: James Burrus, jburrus@nist.gov, 303-497-4789

back to top

Newly Improved NIST Reference Material Targets Infant Formula Analysis

Chemists at the National Institute of Standards and Technology (NIST) have issued a new certified reference material--a standardized sample backed by NIST--for determining the concentrations of vitamins, minerals and other nutrients in infant and adult nutritional formula and similar products. The new Standard Reference Material (SRM 1849) for Infant/Adult Nutritional Formula, represents a significant improvement over the now discontinued SRM 1846, Infant Formula, which had been offered since 1996.

Proper nutrition is essential for proper development in infants; too much or too little of certain nutrients can be harmful or even fatal. According to NIST chemist Katherine Sharpless, infant formula is one of the most regulated food items in the United States. Manufacturers are bound by the Infant Formula Act of 1980 (Public Law 96-359) to test their formula to ensure that the nutrient levels conform to ranges and minimums as specified in the statute.

NIST researchers chose to replace the older SRM for a number of reasons. The process of obtaining NIST-certified values for a candidate reference material can be lengthy and expensive. When NIST first released SRM 1846, there were a number of other available reference materials that had certified values for elements, so NIST researchers did not measure those values in SRM 1846, publishing them only as “reference values” measured by other laboratories. (NIST does not certify values measured by other institutions.) Moreover, in 1996 NIST did not have in-house methods to certify values for fatty acids, vitamins D and K, and many water-soluble vitamins, so those, too, relied on the work of collaborating laboratories. As a result, NIST released SRM 1846 with only five certified values, 38 reference values and nine information values.

Foremost among the reasons that led to the decision to replace SRM 1846 was the fact that the material no longer presented the same analytical challenge as commercially available formulas. SRMs should ideally be no more and no less difficult to analyze than the material they are intended to simulate.

SRM 1849 is the culmination of NIST researchers’ efforts to expand and improve upon the previous material. The new SRM contains certified values for 43 nutrients, including vitamins, minerals and elements, and 43 reference values for amino acids and nucleotides. According to Sharpless, SRM 1849 is one of the most well-characterized food SRMs that NIST now produces.

NIST SRMs are intended to be used as controls in analytical chemical testing, and certified values simply describe what the SRM contains and are not intended to prescribe what a consumer product should contain. SRM 1849 does not conform to the Infant Formula Act of 1980 and is not intended for consumption.

Standard Reference Materials are among the most widely distributed and used products from NIST. The agency prepares, analyzes and distributes more than a thousand different materials that are used throughout the world to check the accuracy of instruments and test procedures used in manufacturing, clinical chemistry, environmental monitoring, electronics, criminal forensics and dozens of other fields. For more information, see NIST’s SRM Web page at http://ts.nist.gov/measurementservices/referencematerials. For more information on SRM 1849, Infant/Adult Nutritional Formula, see https://www-s.nist.gov/srmors/view_detail.cfm?srm=1849.

Media Contact: Mark Esser, mark.esser@nist.gov, 301-975-8735

back to top

Who Are You? Mobile ID Devices Find Out Using NIST Guidelines

A new publication that recommends best practices for the next generation of portable biometric acquisition devices--Mobile ID--has been published by the National Institute of Standards and Technology (NIST).

hand holding mobile device

Mobile ID devices allow users in the field to collect biometrics and compare them with identity databases wirelessly.

Credit: Orandi, NIST
View hi-resolution image

Devices that gather, process and transmit an individual’s biometric data—fingerprints, facial and iris images—for identification are proliferating. Previous work on standards for these biometric devices has focused primarily on getting different stationary and desktop systems with hardwired processing pathways to work together in an interoperable manner. But a new generation of small, portable and versatile biometric devices are raising new issues for interoperability.

“The proliferation of smaller devices including advanced personal digital assistants (PDAs), ultra-portable personal computers and high-speed cellular networks has made portable biometric systems a reality,” computer scientist Shahram Orandi says. “While the portable systems have made leaps and bounds in terms of capability, there are still intrinsic limitations that must be factored into the big picture to ensure interoperability with the larger, more established environments such as desktop or large server-based systems.”

The new mobile biometric devices allow first responders, police, the military and criminal justice organizations to collect biometric data with a handheld device on a street corner or in a remote area and then wirelessly send it to be compared to other samples on watch lists and databases in near real-time. Identities can be determined quickly without having to take a subject to a central facility to collect his or her biometrics, which is not always possible.

Soldiers are beginning to use these devices to control access to secured areas, and first responders can use them to ensure that only approved workers are on-site during an incident or investigation.

Special Publication 500-280: Mobile ID Device Best Practice Recommendation Version 1 offers guidelines to help ensure that, if followed, mobile and stationary systems will work together. It was developed by NIST researchers working with first responders, criminal justice agencies, the military, industry and academia.

For example, most current law enforcement applications require capturing all 10 fingerprints from an individual. Desktop fingerprint scanners provide a large scanning area—a platen—that can capture all 10 fingers in a fast, three-step process. Most portable devices, however, have platens that are a fraction of the size of a desktop scanner. The Mobile ID best practices publication provides guidelines that allow for the capture of all 10 fingerprints on a scanner with a smaller platen using a two-fingers-at-a-time approach.

The publication is available at http://www.nist.gov/customcf/get_pdf.cfm?pub_id=903169.

Media Contact: Evelyn Brown, evelyn.brown@nist.gov, 301-975-5661

back to top

Hankering for Molecular Electronics? Grab the New NIST Sandwich

ultra-smooth gold surface
rough gold surface

The flip-chip lamination method creates an ultra-smooth gold surface (left), which allows the organic molecules to form a thin yet even layer between the gold and silicon. Gold surfaces created by other methods are substantially rougher (right), and would result in many of the molecular switches either being smashed or not contacting the silicon.

Credit: Coll Bau, NIST
View hi-resolution left image and right image.

The sandwich recipe recently concocted by scientists working at the National Institute of Standards and Technology (NIST) may prove tasty for computer chip designers, who have long had an appetite for molecule-sized electronic components – but no clear way to satisfy it until now.

The research team, which includes collaborators from the University of Maryland, has found a simple method of sandwiching organic molecules between silicon and metal, two materials fundamental to electronic components. By doing so, the team may have overcome one of the principal obstacles in creating switches made from individual molecules, which represent perhaps the ultimate in miniaturization for the electronics industry.

The idea of using molecules as switches has been around for years, carrying the promise of components that can be produced cheaply in huge numbers, perform faster as a group than their larger silicon brethren, and use only a tiny fraction of their energy. But although there has been progress in creating the switching molecules themselves, the overall concept has been stuck on drawing boards in large part because organic molecules are delicate and tend to be damaged irreparably when subjected to one particularly stressful step in the chip-building process: attaching them to electrical contacts.

Metal forms many of these contacts in chip circuits, but getting metal onto a chip involves heating it until it evaporates, then allowing it to condense on the silicon. “Imagine what hot steam would do to your arm,” says Mariona Coll Bau, a materials scientist at NIST. “Evaporated metal is much hotter, and organic switching molecules are very fragile—they can’t stand the heat.”

Coll Bau’s team, however, found a way to cool the kitchen. They cover a surface with a non-stick material before condensing gold on top of it, allowing the metal to cool to an ultra-smooth surface. They then laminate the gold surface with the plastic used in overhead transparencies. The non-stick layer allows them to remove the laminated gold from the surface as easily as peeling off plastic wrap. Adding the organic molecules then is comparatively simple: attach the molecules to the gold and then flip the whole assembly onto a silicon base, with the organic molecules sandwiched neatly inside—and intact.

Though scientists have attempted to make sandwiches of this sort before, Coll Bau says their first-ever use of an imprinting machine finally made it possible to assemble the ingredients effectively. “The machine allows us to press the three layers together so the organic molecules contact both the silicon and gold, but without smashing or otherwise degrading them,” she says.

Coll Bau adds that “flip-chip lamination,” as the team calls it, could lead to applications beyond chip design, including biosensors, which depend on the organic and electronic worlds interacting. “The technique may prove useful as a fabrication paradigm,” she says. “It’s hard to make small things, and this might be an easier way to make them.”

* M. Coll, L.H. Miller, L.J. Richter, D.R. Hines, O.D. Jurchescu, N. Gergel-Hackett, C. Richter and C.A. Hacker. Formation of silicon-based molecular electronic structures using flip-chip lamination. Journal of the American Chemical Society, Aug. 11, 2009 (online publication), DOI 10.1021/ja901646j.

Media Contact: Chad Boutin, boutin@nist.gov, 301-975-4261

back to top

With Three New Reference Materials, NIST Gets the Dirt on Soil

The National Institute of Standards and Technology (NIST) has issued three new certified reference materials for soil. Intended for use as controls in testing laboratories, the new Standard Reference Materials (SRMs)—gathered from the San Joaquin Valley in California and from sites near Butte and Helena in Montana—will aid in determining soil quality, detecting soil contamination, and monitoring cleanup efforts from accidental spills or atmospheric deposition.

Whether for evaluating soil quality and health, suitability for crop use, assessment of contamination, or for environmental monitoring, analyses of soils are performed routinely by a variety of commercial, government, and university laboratories around the United States and the world. The three new soil SRMs are 2709a, San Joaquin Soil, 2710a, Montana Soil I, and 2711a, Montana Soil II. They come with NIST-certified values for most elements regulated by the Environmental Protection Agency, including those identified as priority pollutants in the Clean Water Act and those specified as hazardous air pollutant elements in the Clean Air Act. NIST created its first batch of sample soils, which the new SRMs replace, about 20 years ago. Efforts to restock the supply with an updated SRM began in 2006.

Scientists at the United States Geological Survey’s (USGS) Denver, Colo., laboratory collected the soil for the new SRMs from either the same or near the same locations as they had collected the original soils. The USGS team then prepared the soil samples by individually drying them, sifting them, and blending them before they were packaged and sent to NIST for further processing.

Using non-destructive methods whenever possible, NIST researchers certified most values for elemental and chemical constituents with two or more analytical techniques. USGS scientists provided additional confirmation of the certified NIST values. Altogether, the team published certified, reference and information values for 44, 48 and 45 elements in SRMs 2709a, 2710a and 2711a respectively.

Standard Reference Materials are among the most widely distributed and used products from NIST. The agency prepares, analyzes and distributes more than a thousand different materials that are used throughout the world to check the accuracy of instruments and test procedures used in manufacturing, clinical chemistry, environmental monitoring, electronics, criminal forensics and dozens of other fields. For more information, see NIST’s SRM Web page at http://ts.nist.gov/measurementservices/referencematerials. For more information about the new soil SRMs, visit https://www-s.nist.gov/srmors/viewTable.cfm?tableid=86.

Media Contact: Mark Esser, mark.esser@nist.gov, 301-975-8735

back to top

Biometrics Conference Meets Sept. 22–24 in Florida

The National Institute of Standards and Technology (NIST) and the National Security Agency (NSA) are cosponsoring the Biometric Consortium Conference 2009 on Sept. 22-24 at the Tampa (Fla.) Convention Center.

The Biometric Consortium Conference focuses on biometric technologies—methods to identify humans using one or more intrinsic physical or behavioral characteristics—for national defense, homeland security, law enforcement, identity management, border crossing, electronic commerce and other applications. The conference offers two and a half days of presentations, seminars and panel discussions with internationally recognized experts in biometric technologies, system and application developers, IT business strategists, and government and commercial officers.

Attendees—including policy developers and decision-makers, government and industry executives, information technology users and developers, law enforcement officials, systems integrators and researchers—will be able to hear and discuss management and implementation issues across a broad spectrum of government agencies.

Keynote speakers include the Department of Defense’s director of defense research and engineering and chief technology officer, Zachary J. Lemnios; John M. (Mike) McConnell, senior vice president at Booz Allen Hamilton and former Director of National Intelligence; and Louis E. Grever, executive assistant director, Science & Technology Branch, Federal Bureau of Investigation.

In addition to federal agency-related tracks, there will be sessions on the role of biometrics in health care, biometrics in education and training, biometrics in cyber security, biometric standards, international activities in biometrics and biometric-enabled intelligence. This year, the First IEEE International Conference on Biometrics, Identity and Security (BIdS) will be co-located with the Biometric Consortium Conference. This conference is being organized and sponsored by the IEEE Biometrics Council.

The Biometric Consortium Conference will include a number of separate workshops including “Virtual Identity – the Rise of the Avatars and the Shadow Internet,” “IEEE Certified Biometrics Professional Program,” “Biometrics Testing & the Emergence of Biometric Laboratory Certification,” “Emerging Biometrics” and “Biometrics 2020 – A Needs-Based View of How Large-Scale Biometric Architectures Will Evolve Over the Next 10 Years.”

For more information and to register see www.biometrics.org/bc2009. Members of the news media interested in attending should contact Evelyn Brown, evelyn.brown@nist.gov, (301) 975-5661.

Media Contact: Evelyn Brown, evelyn.brown@nist.gov, 301-975-5661

back to top

Quicklinks

Bio-Imaging Technology Transfer and Commercialization Showcase

On Oct. 6, 2009, the Maryland Technology Development Corporation (TEDCO) will sponsor a technology transfer and commercialization showcase for bio-imaging technologies developed by the National Institute of Standards and Technology (NIST) and the National Institutes of Health (NIH). The showcase will be held at NIST’s campus in Gaithersburg, Md., and will feature more than 50 government-developed technologies available for licensing or use by interested individuals, small businesses and corporations.

“Discover and Commercialize Cutting Edge Bio-Imaging Technologies” is one of more than 30 technology transfer and commercialization showcases hosted by TEDCO. TEDCO, an agency of the state of Maryland, was created in 1998 to fund and foster entrepreneurship and small businesses and facilitate the transfer of knowledge and technology from the public to the private sector. TEDCO is the leading source of funding for technology transfer programs in the state of Maryland.

In addition to the more than 50 new technologies that will be showcased, the event also will feature two dozen speakers, 12 from NIST and 12 from NIH, information on laboratory facilities at NIH and NIST that are available for public use, and a tour of NIST facilities. NIST researchers will be demonstrating bio-imaging technologies, such as a passive terahertz heterodyne imager for biomedical applications and quantitative molecular sensors and imaging techniques for diagnostic detection of infectious diseases, among others.

The showcase is open to the public, but attendees must register. The cost of admission is $80 per person. Attendees who are not U.S. citizens must register by Sept. 21. U.S. citizens must register by Sept. 30. Lunch is included. For contact information, registration, or to learn more about the showcase, please visit www.marylandtedco.org.

Media Contact: Mark Esser, mark.esser@nist.gov, 301-975-8735

back to top