In This Issue:
NIST
to Propose Inspection Standard to ISO
Conference to
Link Technology Programs, Economic Growth
An
AC Source with Quantum Mechanical Accuracy
NIST, USFA
Strengthen Firefighting Partnership
Semiconductor
Wire Bonding 'Bible' Expanded
Stress,
Strain Effects on Energy Storage System Defined
Three NIST
Researchers Receive Presidential Honor
[Credits] [NIST Update Archives] [Media Contacts] [Subscription Information]
Manufacturing
NIST to Propose Inspection Standard to ISO
With U.S. companies nodding their approval, NIST will advance a proposal to develop an international standard for computer-to-computer exchanges of dimensional inspection information, making it readily available for design, manufacturing, quality assurance and other uses.
In a series of workshops, NIST found that manufacturers often were frustrated by the exclusion of inspection planning and dimensional requirements from computer-aided design packages. Companies also complained that incompatible data formats undermined sharing of part data and inspection results among software applications. NIST and its industrial partners will soon ask the International Organization for Standardization (known as ISO) to initiate efforts toward a standard to resolve such problems. The request will be directed to the ISO committee guiding further development of STEP, the STandard for Exchange of Product model data. Formally known as ISO 10303, STEP provides an unambiguous format for representing and communicating data relevant to all phases of a product's life cycle.
As proposed by NIST, the new inspection standard would be a component of STEP. NIST researchers anticipate that the existing U.S. Dimensional Measuring Interface Standard would be compatible. The proposed standard's scope of activities would be larger and, as part of STEP, integrated with other product data standards.
For more information, contact Simon Frechette, or Howard Harary.
Media Contact:
Mark
Bello (301) 975-3776
ATP
Conference to Link Technology Programs, Economic Growth
What role does technology development play in economic growth, and more importantly, just how do you measure it? This is the thorny issue behind the International Conference on the Economic Evaluation of Technological Change planned for June 15-16, 1998, at the Georgetown University Conference Center in Washington, D.C. The conference is sponsored by the Department of Commerce's Advanced Technology Program in cooperation with the National Bureau of Economic Research.
Focusing on the empirical assessment of the effects of government investment in science and technology in advanced industrial economies, the conference will bring together policy makers, analysts and R&D managers, and academic researchers studying technology evaluation issues to present and compare experiences in policies, evaluation methods and practices in different countries. Planned keynote speakers include Zvi Griliches of Harvard University, Edwin Mansfield of the University of Pennsylvania and Rebecca Henderson of the Massachusetts Institute of Technology.
Deadline for submission of papers or abstracts is Jan. 31, 1998, with completed manuscripts due by May 5. Deadline for registration is May 10; the registration fee is $300.
For more information, consult the ATP website at http://www.atp.nist.gov, or contact Richard Spivak.
Media Contact:
Michael
Baum (301) 975-2763
Electromagnetics
An AC Voltage Source with Quantum Mechanical Accuracy
Scientists in NIST's Electromagnetic Technology Division have demonstrated proof of principle for an alternating current voltage source based on the perfectly quantized voltage pulses of Josephson junctions. Arrays of Josephson junctions form the basis for this standard.
The NIST scientists have been able to demonstrate how a complex pattern of pulses driving an array of 1,000 junctions produces a smooth sinewave voltage with high resolution and accuracy. The arrays use superconductor-normal-superconductor (or SNS) junctions that can generate inherently stable and accurate voltages. The arrays respond to broadband microwave inputs that can be programmed to generate metrologically accurate AC waveforms. The input consists of a long, repetitive digital pulse train clocked at frequencies up to 12 gigabits per second. In preliminary experiments using arrays of 1,000 junctions, this SNS technique has been used to synthesize both stable constant (DC) voltages and sinewaves of a few millivolts in amplitude at frequencies up to 1 megahertz.
The researchers continue to focus on increasing the clock frequency and the number of junctions in the array in order to achieve a voltage range of plus-or-minus one volt.
A paper, no. 41-97, describing this development is available from Sarabeth Harris, MC 104, NIST, Boulder, Colo. 80303-3328.
Media Contact:
Fred
McGehan (Boulder) (303) 497-3246
Fire Research
NIST, USFA Strengthen Firefighting Partnership
American fire prevention and firefighting efforts were strengthened on Nov. 5, 1997, when NIST and the Federal Emergency Management Agency's United States Fire Administration announced joint plans to better meet the research needs of the fire safety community.
The agreement calls for improved and more effective coordination of fire safety efforts through mutual consultation, research coordination and technology transfer. The two organizations promise to:
- consult on the content and priorities of NIST fire research;
- improve the exchange of information--between the two organizations and with the fire safety community--relating to research needs and results;
- increase the transfer of technology between USFA, NIST and their customers;
- establish joint research program planning, reviews and coordination; and
- set guidelines for formulating joint and cooperative research activities, support and/or technical assistance tasks.
In addition, NIST and USFA fire officials will meet at least every two months to review progress, accomplishments and priorities. Library and web site services will be coordinated, and an annual conference on fire prevention and control will be held.
Media Contact:
John
Blair (301) 975-4261
Electronics
Semiconductor Wire Bonding 'Bible' Expanded
Every year 4 trillion wire bonds are made to interconnect silicon chips to their electrical circuitry. This process, called wire bonding, is the world's most frequently performed sophisticated manufacturing step. Now, George G. Harman, a NIST fellow in the Semiconductor Electronics Division of the Electronics and Electrical Engineering Laboratory, has made life a little less complicated for those who make such bonds.
Harman recently revised and expanded Wire Bonding in Microelectronics-- Materials, Processes, Reliability and Yield, a technical bible for chip manufacturers since 1989. In addition to reviewing classical metallurgical problems, the updated edition provides information on new materials, new interconnect techniques, and the pros and cons of alternative bonding technologies. It offers guidance on testing wire bonds; cleaning bond pads to improve bondability and reliability; and solving cratering, bond fatigue and other mechanical problems.
The book also provides contemporary details such as bonding to multichip modules, utilizing fine pitch bonding, applying new bonding metallurgies and a description of the wire bonding mechanism. The new edition is a volume in the McGraw-Hill series on Electronic Packaging and Interconnection.
For information on how to order his book, contact George G. Harman, B344 Technology Bldg., NIST, Gaithersburg, Md. 20899-0001.
Media Contact:
John
Blair (301) 975-4261
Superconductivity
Stress, Strain Effects on Energy Storage System Defined
Superconducting magnetic energy storage units planned by electric utilities will require large quantities of thermal stabilizer to protect the superconductor. One design calls for a niobium-titanium-copper cable to be stabilized with a high-purity aluminum jacket and structurally supported with a high-strength aluminum alloy overwrap. High-purity aluminum has lower electrical resistivity at liquid helium temperatures than a copper stabilizer, and its density is lower, resulting in reduced magnet size and mass. However, the cable will be subjected to stress and strain during normal operation as power system requirements change.
To study these effects, NIST scientists tested aluminum-composite test rings from high-purity aluminum and high-strength aluminum alloy. Magnet operating conditions were simulated. One test subjected a composite ring to fatigue at 4 Kelvin with the peak hoop stress held constant and the ring's electrical resistance periodically measured. A second fatigue test held the peak hoop strain constant. In both tests, the initial peak strain was 0.21 percent. In the constant-strain test, the increase in resistivity after 4,000 fatigue cycles was 40 percent greater than for the constant-stress test, indicating a significant strengthening of the composite through work hardening of the aluminum.
These results allow for a substantial reduction in the required quantity of high-purity aluminum stabilizer and, therefore, in the cost for magnets.
A paper, no. 40-97, describing this work, is available from Sarabeth Harris, MC104, NIST, Boulder, Colo. 80303-3328.
Media Contact:
Fred
McGehan (303) 497-3246
Awards
Three NIST Researchers Receive Presidential Honor
Three scientists at NIST were among 60 young researchers named by President Clinton on Oct. 23, 1997, to receive the second annual Presidential Early Career Awards for Scientists and Engineers. The award recognizes outstanding men and women scholars in both disciplines for "their research contributions, promise and commitment to broader societal goals."
This year's PECASE recipients from NIST are Gregory T. Linteris, Building and Fire Research Laboratory, Gaithersburg, Md.; Christopher R. Monroe, Physics Laboratory, Boulder, Colo.; and Thomas J. Silva, Electronics and Electrical Engineering Laboratory, Boulder, Colo.
Ten government agencies join together annually to nominate candidates for the award. Those selected receive up to $500,000 over a five-year period to further their research and broadly advance science for important government missions.
Media Contact:
Mike
Newman (301) 975-3025
