Technology at a Glance is a quarterly newsletter from the National Institute of Standards and Technology reporting on research results, funding programs, and manufacturing extension and technology services. If you have comments or general questions about this newsletter or if you would like to receive the four-page, color newsletter in hard copy, please email your mailing address to Gail Porter, editor, or call (301) 975-3392. About Technology at a Glance. 

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Trace Gas Method Boosts Sensitivity

Bigger isn’t always better. A team of NIST chemists recently proved this is true for trace gas measurements of water vapor or oxygen. The team found they could make measurements of gas concentrations that are 100 times more sensitive with a testing chamber that is one-tenth the size of previous
models.

The semiconductor industry has rigorous requirements for the purity of gases used in the fabrication of integrated circuits. One way to test for impurities such as water vapor or oxygen is a technique known as cavity ring-down spectroscopy. The conventional implementation of this technique involves putting a sample of the gas to be tested into a chamber about 1 meter long and shining an infrared laser into the enclosure. The infrared light bounces back and forth between two mirrors at the ends of the chamber. The laser light is tuned to a wavelength that is absorbed by the molecule to be detected. By measuring the rate that light leaks from the chamber, scientists can determine the concentration of the contaminant.

Conventional wisdom has held that longer chambers should provide better sensitivity. Longer chambers leak light at a slower rate, so small changes in light levels should be easier to detect. However, the NIST group observed that light wave interactions within meter-long chambers complicated the detected signals.

To eliminate these interactions, the NIST researchers used a pulsed laser and made
a chamber only 10 cm long. They found that tiny changes in the distance between the two mirrors in the chamber gener-ated distinct wave patterns.

The image above shows three of these distinct wave patterns. In each of these three patterns, yellow represents the areas with highest light intensity, followed by red and then blue areas. By carefully controlling the laser wavelength and cavity length to produce the simplest pattern (on the left), the unwanted interactions were eliminated and sensitivity of the method was enhanced greatly.

Contact: Roger van Zee, (301) 975-2363.

Proteins Hold Key to Curing Diseases

Although much of your destiny may lie in your genes, don’t forget about your proteins. They may hold the key to overcoming many harmful effects caused by those genes.

The importance of proteins has been made abundantly clear by CuraGen Corp., a New Haven, Conn., company that has created a novel set of technologies designed to gain a better understanding of the role proteins have in diseases. CuraGen’s goal is to better explain, prevent, and treat complex diseases, such as neurologic and metabolic disorders. A number of CuraGen’s technologies are based upon hardware and software developed in two projects co-funded by NIST’s Advanced Technology Program between 1995 and 1998. A third ATP project is under way.

Back in the early 1990s, ATP was one of the only sources of substantial funding for gene expression research. The company had only 17 employees then. Now, CuraGen has grown to 300 employees, and its research has produced important national benefits:

• The ATP-funded research has led to three new processes, an array of new patents, and more than $100 million worth of research collaboration and technology access deals with six companies.

• One new CuraGen technology is able to detect greater than 90 percent of the differences in gene activity in humans, animals, plants, and pathogens.

• The technologies have provided substantial information for development of products to improve the health of humans, animals, and plants.

The ATP projects have led to three automated processes that are now being commercialized. Ultimately, CuraGen hopes to reduce the high costs associated with uncured diseases and high failure rates in the development of new drugs and agricultural products. The company has estimated that its technologies can save the nation more than $1 billion annually by reducing the time and cost involved in identifying promising drug compounds and eliminating poor candidates from pre-clinical and clinical studies.

Contact: Mark Vincent, 1-888-GENOMICS.

Atom Optics: When 3+0=4

A new field of physics—non-linear atom optics—has been opened by NIST physicists through a series of recent experiments. The experiments demonstrate for the first time that atoms can display some unusual properties previously only seen with high intensity light waves.

Using sodium atoms cooled to very near absolute zero, the NIST team demonstrated that three atom waves can be mixed to produce a fourth wave, in exactly the manner as optical laser beams can be combined to form a new laser light beam. These experiments, conducted in vacuum, show that under very specific conditions, the interacting matter waves can mimic the way high-intensity laser light waves behave in certain materials.

The experiments, reported in the March 18 issue of Nature, were conducted in
collaboration with theorists from NIST and Ben-Gurion University in Israel. Calculations by the theorists that predicted the behavior of the atom waves were confirmed by the experiments.

To conduct their experiments, the NIST physicists first created a dense cloud of very cold atoms in which all the atoms fell into their lowest possible energy states and became indistinguishable from one another. This exotic state of matter is known as a Bose-Einstein condensate. It was first predicted by Albert Einstein more than 70 years ago and was first achieved in a gas by researchers at NIST and the University of Colorado in 1995.

Next, the scientists pulsed beams of laser light with specific directions and frequencies on the Bose-Einstein condensate, thereby splitting it into three distinct, intense matter waves. Each matter wave had a unique velocity and direction. The scientists applied the same rules governing light to determine the necessary velocities and directions to mix the three matter waves so that they would form a fourth. As anticipated, the interaction of the matter waves produced a fourth wave (see smaller peak in graphic above.) with just the properties that had been predicted.

Scientists expect the new field of non-linear atom optics will parallel the development of non-linear optics, which emerged as scientists discovered many of the strange, unique, and unexpected abilities of laser light following the demonstration of the first laser in 1960.

Contact: Kristian Helmerson, (301) 975-4266.

Better Reference Detectors

Sometimes a detector material can be too sensitive. Lithium niobate, for instance. This material is a crystal that is both pyroelectric—it produces an electrical signal in response to temperature changes—and piezoelectric—it produces an electrical signal in response to vibrations such as sound waves.

NIST researchers recently produced an improved detector from lithium niobate that can be used to calibrate infrared, ultraviolet, and visible light sensors. The detector provides more accurate readings of power output for lasers, lamps, and other light sources by removing the piezoelectric signal from the measurements. Infrared measurements, for example, can be made with uncertainties that are about eight times lower than those made with similar NIST reference detectors in a typical laboratory environment.

The detector has a circular, central region in which electricity flows in one direction, and a region around the circle in which the flow is reversed. The NIST research group reversed the flow with a process called domain engineering in which the order of atoms in different parts of the crystal is changed. A very thin metal plate shades the area with the reversed orientation. The central region senses both light and sound, while the outer region senses only sound. This allows the sound portion of the signal to be canceled out, thereby greatly reducing “noise” in the detector’s electrical signal.

The graphic above of a more complex detector shows the NIST researchers’ ability to finely tune the patterns of atoms in the crystal and, therefore, the detector response. The detector was patterned so that when a laser was scanned across it a positive signal was produced in the regions that spell out the word NIST. The detector is 15 mm wide and has a pattern resolution of about 125 micrometers.

Contact: John Lehman, (303) 497-3654. 

Sensor Predicts Electrical Failures

NIST scientists have developed the first practical system to continuously measure small pulses of electricity that ultimately lead to the failure of expensive high-voltage equipment.

The so-called “partial discharge” pulses, which can be likened to extremely weak sparks, appear randomly and are not detected by high-voltage test equipment. They commonly occur at points where insulation is at its weakest, gradually damaging the insulation until it fails altogether.

The lightweight, portable NIST system uses specialized software to continuously record and analyze pulses in power generation, transmission, and other high-voltage equipment. Utility companies can use this information to monitor equipment and get repairs made before failures occur. The system detects pulses up to 100,000 times weaker than the typical “static electricity” spark caused by touching metal in dry conditions.

The U.S. Air Force provided partial support for the NIST research. Military and other aircraft currently rely extensively on heavy hydraulic controls to operate wing flaps, rudders, landing gear, and other systems. Lighter weight electric motors would help improve fuel efficiency but are less reliable. Accurate monitoring with the NIST discharge detector could allow manufacturers to replace hydraulic controls with electrical systems, while ensuring aircraft safety.

Contact: Yicheng Wang, (301) 975-4278.

Round Molecules Find Many Uses

A Koosh™ ball is made out of rubber strings and is very easy to catch. A dendrimer molecule looks like a Koosh™ ball and, not surprisingly, it's good at catching things.

Dendrimers are a relatively new type of polymer that soon may find a wide variety of uses. The unusual shape of dendrimers provides a number of useful properties. The stringy ends supply attachment points for specific molecules such as enzymes that can be used to detect trace levels of biological or chemical substances.

Illustration by Jeffrey Aarons

The open areas in the middle of the molecule provide tiny cages for metal clusters or pharmaceuticals (see graphic above). This allows dendrimers to serve as a kind of delivery system for drugs targeted to specific areas of the body or as a way to spread nanometer-sized metal particles across a surface to build novel materials for optical or magnetic devices. The compact, round shape allows the molecule to pass through
cell walls that would be impenetrable to more ordinary, spaghetti-shaped polymers.
In a multiyear project supported in part by the U.S. Army Research Office, NIST
researchers are studying the size, shape, and interactions of dendrimers. The NIST group is working in collaboration with dendrimer producers, users, and university researchers. The researchers have used a number of different techniques like neutron scattering, X-ray scattering, and transmission electron microscopy to examine dendrimers.

They have found that these molecules range in size from about 1 to 15 nm and that when packed together they shrink like grapes turning into raisins. The research also shows that the highly reactive amino groups attached to the ends of dendrimer structures primarily are pointing outward in all directions like the strings of Koosh™ balls, rather than being tucked inside the molecule.

Contact: Barry Bauer, (301) 975-6849.

Precast Concrete Gets Set to Stand Tall

A new way to make tall buildings earthquake resistant made its debut in August as construction got under way on a 39-story apartment tower in San Francisco. When complete, the building will be the tallest precast concrete structure ever built in an active U.S. earthquake zone. NIST researchers started working on new ways to use precast concrete in buildings in earthquake zones more than a decade ago. Collaborative work by NIST with the University of Washington and Charles Pankow Builders Ltd. of Altadena, Calif., led to a new connection design for precast concrete buildings which involves the use of high strength steel cables and mild steel bars that stretch during an earthquake and then snap back into place. Tests at NIST show that the new design will perform as well as cast-in-place concrete construction. Precast concrete is preferable in some circumstances because it offers better quality control and can speed up construction. In large buildings, the use of precast concrete can, in some cases, save millions of dollars.

Contact: H.S. Lew, (301) 975-6060.

‘Across the Road’ Radar Comes of Age

More and more police are using photo-radar and radar speed detection systems that are aimed across the road instead of parallel to or along it. This provides advantages of easier concealment and decreases the chance that motorists will detect the radar in time to slow down. However, the new systems require frequent calibrations using a more complicated method than the tuning fork calibrator used by the old style of radar guns. NIST researchers have developed an inexpensive, portable instrument that receives the radar pulses, processes them internally, and sends a modified signal back to the radar. The modified signal simulates radar reflections from a variety of vehicles ranging in size from motorcycles to 18-wheel tractor-trailers. It can simulate several trucks traveling close together, and simulate targets moving toward or away from the radar at a specific speed. The simulator also can be used to determine whether or not the radar meets the performance standards established by the industry and police associations.

Contact: Robert Johnk, (303) 497-3737

Office Cubicles Soon May Become ‘Smart Spaces’

NIST is launching a pervasive computing initiative that involves developing tests and standards that will catalyze advancements in fields ranging from wireless devices to wearable computers. NIST scientists believe three trends are shaping the future of the information technology industry: the growing number of computers per person in homes and offices, advances in miniaturization technology, and the phenomenal growth of the Internet. The convergence of these trends will result in an era of pervasive computing. Computers, actuators, and sensors will be embedded in virtually every device, appliance and piece of equipment, and even in clothing. One field that is ready for advanced research is the development of “smart spaces.” These are work spaces that have many built-in computers, sensors, and communications devices, such as voice recognition systems. NIST currently is developing an experimental smart space as a first step in its pervasive computing initiative.

Contact: Martin Herman, (301) 975-4495.

Controlling Semiconductor ‘Recipes’ in Real Time

The U.S. semiconductor industry is being transformed by new software that increases process consistency and yield. The advanced process control technology was designed and demonstrated by Honeywell Inc. of Minneapolis and Advanced Micro Devices of Austin, Texas. The project was conducted in cooperation with SEMATECH, an industry consortium, with co-funding from NIST’s Advanced Technology Program. The project developed a flexible, universal toolset for process control and wafer fabrication equipment. The toolset can be deployed rapidly across process areas and factories with minimal custom adaptation. The software detects and classifies processing faults and adapts processing as needed from one wafer or batch to the next by tweaking the “recipes” used to operate equipment. The ATP project produced an 83 percent reduction in photolithography rework and a 48 percent reduction in variability in microprocessor speed. The technology is being commercialized for the semiconductor industry and may have applications in other industries as well.

Contact: Anoop Mathur, (612) 951-7734.

X-Ray Detector—NIST has granted co-exclusive licenses to EDAX Inc. of Mahwah, N.J., and NORAN Instruments Inc. of Middleton, Wis., for commercialization of a microcalorimeter-based X-ray detector with an energy resolution of two electron volts, some 50 times better than conventional semiconductor-based detectors. The new technology will be used in instruments for the characterization and analysis of materials by X-rays in semiconductor and other materials-intensive industries. The vastly improved detector system will enable chemical analysis of particles that are difficult or impossible to study with current detectors.

Contact: Richard Harris, (303) 497-3776.

Solar Heater—A novel system that uses the power of the sun to directly heat water is about to become commercially available after years of development and testing at NIST. An exclusive license has been granted to Four Seasons Solar Products Corp. of Holbrook, N.Y., to use the NIST patented technology. The solar water heating system is the first to use photovoltaic cells and computer chips to harness and direct the sun’s energy. The system eliminates durability and reliability issues associated with previous solar thermal hot water systems.

Contact: Hunter Fanney, (301) 975-5864.

Meat Standard—At the request of the Food Safety Inspection Service of the U.S. Department of Agriculture, NIST chemists have developed a Meat Homogenate Standard Reference Material (SRM 1546). This new reference material will help food testing and nutrition laboratories verify the accuracy of the nutrient composition values they assign to canned and processed meats. Labs purchasing SRM 1546 will get four cans (85 grams each) of blended pork and chicken with a certificate that reports just how much fat, protein, carbohydrate, vitamins, minerals, and calories the meat product contains. Food chemists will measure the nutrients in a portion of the meat reference material and then compare their results to the values listed on the certificate. This quality check allows labs to evaluate their own performance.

Contact: SRM Program, (301) 975-6776.

About Technology at a Glance:

NIST is an agency of the U.S. Department of Commerce's Technology Administration. NIST promotes U.S. economic growth by working with industry to develop and apply technology, measurements, and standards. Technology at a Glance is produced by Public and Business Affairs, NIST, 100 Bureau Dr., Stop 3460, Gaithersburg, Md. 20899-3460. Any mention of commercial products is for information only; it does not imply recommendation or endorsement by NIST. Technology at a Glance Editor: Gail Porter, (301) 975-3392, email: gail.porter@nist.gov. For patent information, call (301) 975-3084.

Technology at a Glance Archive Files

Last updated: August 13, 1999
Crissy Wines