U.S. DEFWRTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

NBS SPECIAL PUBLIQMION 733
Cover photo: in a demonstration of the Meissner

effect, a permanent magnet

floats above a Y-Ba-Cu-O

superconductor at 77 K.

Potential applications of the

magnetic repulsion of

superconductors include

levitating trains, frictionfree bearings, and magnetic

shielding. See page 5 for

article describing NBS

superconductivity research.
NBS

Research

Reports

CONTENTS

Research Update 2

Riding a Heat Wave:

Researchers Take Another Look at Superconductivity 5

President Reagan Announces Superconductivity Initiative 14

Life on the Edge: Measuring Linewidths 15

Thin-Film Thermocouples Designed for Diesel Engine Research 19

Concrete Research at NBS:

New Ways to Understand an Old Material 20

Improved Clinical Lab Tests: Goal of Cooperative Program 23

Emerging Technologies:

The Competitive Edge of the Future? 24

High-Technology Bugs Are New Tools

for Science and Industry 28

New Publications 30

Conference Calendar 32

U.S. DEPARTMENT OF COMMERCE

Clarence J. Brown, Acting Secretary

National Bureau of Standards

Ernest Ambler, Director

National Bureau of Standards

Gaithersburg, MD 20899

301/975-2000

National Bureau of Standards

Boulder, CO 80303

303/497-3000

August 1987

NBS Special Publication 733

Prepared by tfie Public Information Division A903 Administration Building

National Bureau of Standards

Gaithersburg, MD 20899

301/975-2762

Library of Congress

Catalog Card Number:

87-619861

CODENXNBSAV

Any mention of commercial products

IS for information only; it does not imply recommendation or endorsement

by tfie National Bureau of Standards

nor does it imply that the products mentioned are necessarily the best

available for the purpose.

1
RESEARCH UPDATE

ECOND SPACE-MADE

PRODUCT IS NEW MEASUREMENT TOOL

The second commercial spacemade product, Standard

Reference Material (SRM) 1961,

30-Micrometer Polystyrene Spheres, is a new small-particle measurement standard

developed for industry by NBS. It is an

important quality control tool for chemists

using powders for the manufacture of pharmaceuticals, chemicals, industrial compounds, and products that require particle

sizing near 30 micrometers. Like SRM

1960, 10-Micrometer Polystyrene

Spheres—the first commercial space-made

product offered by NBS in 1985, the new SRM 1961 was made in space by the

National Aeronautics and Space Administration because a low-gravity environment

produces a product that is more uniform in size and shape than Earth-bound pro- cesses for polystyrene materials of this size. SRM 1961 IS a 5-milliliter vial with approximately 1 million of the 30-micrometer

spheres suspended in water. It is available

for $608 from the Office of Standard

Reference Materials, 8311 Chemistry Building, NBS, Gaithersburg, MD 20899,

301/975-OSRM (6776).

C UREAU SUCCESSFULLY

OPERATES 10-VOLT

JOSEPHSON ARRAY

Researchers at the NBS

V Boulder laboratories have

achieved an extremely precise 10-volt output from an array of 14,184 superconducting Josephson junctions. The array may eventually serve as a new standard

for the_^U.S. legal volt at an unprecedented level of accuracy for this voltage.

Develtipment of the array was driven by

increasing demands for calibration of popular 10-volt Zener diode standards.

Such standards are gradually replacing

1-volt Weston-type cells as secondary

standards in industrial and military laboratories around the country. Each

Josephson junction can generate only a few millivolts. Previous 1- or 2-junction

Josephson standards required a complicated resistance bridge tr^ compare the

tiny standard voltage with that of devices

being calibrated.

Increased accuracy is possible,

however, when many Josephson junctions in series can be fabricated on a sin- gle chip, eliminating the need for the

resistance bridge. The array of 14,184

Josephson junctions operated by NBS

researchers realizes a voltage standard at a more useful level— 10 volts. These long

arrays of superconducting junctions are constructed using technology borrowed

from the semiconductor integrated circuit industry, substituting thin films of superconducting metals such as lead and

niobium for the semiconductors.

OMPUTER VISION SYSTEMS

STUDIED

NBS and Martin Marietta Balti- more Aerospace have begun a

joint research program to develop a series of advanced computer-vision

algorithms using the parallel image pro- cessing engine (PIPE), a specialized imageprocessing computer invented at NBS.

Researchers from both organizations will work on algorithms for stereo analysis,

sparse depth maps, two-dimensional

feature extraction— including color and tex- ture as well as geometric features, image

flow, and three-dimensional range information. The algorithms will be applicable to a wide variety of computer vision problems.

: SERS, VENDORS COMPLETE

OSINET FILE TRANSFER TESTS

A group of 13 computer users and vendors was the first to complete a series of tests across OSINET, an experimental computer net- work for Open Systems Interconnection

(OSI) standards. Group members suc- ceeded in accessing, transferring, and

managing files as well as demonstrating

that their OSI systems could work together.

Coordinated by NBS, this network is helping to speed the development and use of commercial OSI products in industry and

government.

Twenty-two computer and communications manufacturers and users, including

several government agencies, are

participating in the program. OSINET

participants have developed their implementations of OSI standards, called

protocols. Using these implementations to communicate with each other and with the

network information center located in the

NBS Institute for Computer Sciences and

Technology, product developers are able to

verify that their systems work with other

systems. The file transfer protocol

implementations used by the OSINET parti- cipants are based on agreements reached

at the ongoing NBS workshops for implementors of OSI. More than 200 computer manufacturers,

semiconductor manufacturers, word pro- cessing vendors, process control vendors,

communication carriers, and industry and

government users participate in the workshops to advance the development of commercial products implementing OSI

standards. The OSINET steering committee

has invited nonparticipants to submit pro- posals for joining the network. For more

information, contact Gerard Mulvenna,

B217 Technology Building, NBS.

Gaithersburg, MD 20899, 301/975-3631.

W BS RECOMMENDS 400TH

I ENERGY-RELATED INVENTION

A new process for continuous

casting of steel cylinders used in manufacturing seamless pipe

and tubing recently became the 400th

invention to be recommended by NBS to the Department of Energy (DOE) for possi- ble assistance in development and

marketing. Through the Energy-Related

Inventions Program, conducted jointly by

NBS and DOE, inventors can receive help

in getting their ideas from the workshop to the marketplace. NBS provides, at no cost

to the inventor, evaluations of energyrelated inventions and recommends those it considers promising to DOE. In turn, DOE

can provide financial support or help in marketing an inventor's idea. The one-time

DOE grants typically have ranged between

$50,000 and $200,000, with an average of $80,000 per invention. Those with ideas

that will help save energy or who would

like more information on the program

should write to the Office of Energy-Related

Inventions, Rm. 209 Engineering

Mechanics Building, NBS, Gaithersburg,

MD 20899.

2
MALL-ANGLE X-RAY

SCATTERING FACILITY

AVAILABLE FOR RESEARCH

A new small-angle x-ray scatter- ing (SAXS) facility at the NBS

Gaithersburg, Maryland, laboratories is now

available to scientists in industry, government, and universities for cooperative and

proprietary research! on the microstructures

of polymers, metals, ceramics, and biological materials. The SAXS instrument uses a

12-kilowatt rotating anode generator to pro- duce a highly collimated pinhole beam of X rays that can probe the internal structures

of materials in the 1- to 100-nanometer size range. The x-ray scattering pattern is picked up on a two-dimensional detector,

recorded, and displayed on a color graphics system. For information on the

NBS SAXS facility or to schedule

cooperative or proprietary research time, contact Dr. John D. Barnes, B210 Polymer

Building, NBS, Gaithersburg, MD 20899,

301/975-6786.

ONSORTIUM FORMED TO

IMPROVE PROCESSING OF

METAL POWDERS

W. NBS has organized a new consortium to develop the basic

measurement system needed by industry

for the automated or "intelligent" processing of rapidly solidified metal powders by

high-pressure, inert gas atomization. The

cooperative 3-year program is open to researchers from industry, universities, and

government agencies who are concerned

about quality control in the production of rapidly solidified metal powders used to make aerospace and other high-technology

products that require materials with superior

performance.

Better control of the atomization of liquid

metals is needed to produce powders with the desired microstructures for advanced

materials. Current powder production is labor intensive and product yield can be

improved.

ALCOA, Crucible Materials Corp.,

General Electric Co., and Hoaganaes Corp.

have already joined the consortium. For

information on the consortium, or to join the

program by providing either funds or researchers, contact Dr. H. Thomas Yolken,

B344 Materials Building, NBS,

Gaithersburg, MD 20899, 301/975-5727.

The small-angle x-ray scattering facility is used by NBS polymer

physicist Dr. John Barnes to obtain information on the microstructures of polymer blends to develop polymer alloy phase diagrams,

inset shows x-ray scattering pattern.

LTRA-CLEAN CERAMIC

PROCESSING LAB SET UP

One of the barriers to the

widespread use of advanced ^ ceramics is the inability of manufacturers to produce materials with consistent performance. Impurities in ceramic powders during compaction,

calcination, and sintering can affect the

microstructures and other properties of advanced materials used in hightemperature engines and turbines, semiconductors, superconductors, and other

aerospace and electronic products.

To study the effects of contamination on the processing and composition of advanced ceramics, NBS has established a clean room facility for producing

powders and sample materials with controlled levels of impurities and dopants.

The laboratory, which has special work

areas where several different projects can

be conducted simultaneously without cross contamination of materials, includes a

laminar flow work area with class-10 clean room conditions and such laboratory equipment as a rotary evaporator, drying oven, a

press for making pellets, and controlled- atmosphere furnaces. For information on

the facility, which is available for cooperative research, write or call Dr. John

Blendell, A258 Materials Building, NBS,

Gaithersburg, MD 20899, 301/975-5796.

OINT AGREEMENT WILL

EXAMINE IMPROVED

CHEMICAL ANALYSIS

J Dionex Corp., a major producer

of ion chromatographic equipment, has signed a cooperative agreement

with NBS that aims to improve methods of separating transition elements, metals such

as nickel and copper, from chemical

samples. These separations are important

preludes to chemical tests by traditional analytical methods such as thin-film x-ray fluorescence, isotope dilution mass spectrometry, and electrochemistry. A significant benefit of improving ion chromatographic

separation techniques is that better quantitation will likely result from follow-up ana3
lytical instruments. Although ion chromatography has many applications, the

NBS/Dionex research will concentrate on

improving tests of biological and biomedical

samples—for example, determining reliably

if toxic levels of nickel or vanadium are contained in biological tissues exposed to

fossil fuel emissions.

IRCUIT CHECKS FOR DATA

CONVERTERS SIMPLIFIED

NBS researchers have devel- oped a method that reduces the

number of tests needed to ensure reliable operation of digital-to-analog converter (DAC) circuits from 1,024 to as few as 13. These circuits are at the heart of computer-based systems, modern test measurements and diagnostic equipment,

and even new home stereo components.

The NBS method combines analytical computer modeling information with actual measured errors obtained from bench test- ing a number of data converters of the same type. From these two sources, researchers can pinpoint which individual clusters of circuit components require attention in order for the overall data conversion

device to operate acceptably. NBS scientists identified 13 calibration points, repre- senting the complex effects of many circuit components, but this number could vary depending on the type of converter circuit. Equipment manufacturers or users could use the simplified strategies of the newer NBS technique to set up a calibration system that would provide measurements

of "acceptable accuracy." For further infor- mation, contact Barry Bell, B162 Metrology

Building. NBS. Gaithersburg, MD 20899,

301/975-2402.

i EASUREMENT

ASSURANCE FOR THE

NUCLEAR POWER

INDUSTRY

NBS and the Atomic Industrial Forum (AIF) have begun a new

measurement assurance program to aid nuclear power facilities in mailing accurate measurements of radioactivity. The pro- gram, conducted by AIF with assistance

from NBS, concentrates on operational and

environmental radioactivity measurements

(not personnel dosimetry) and includes the

distribution of blind standard samples for measurement by participants, analysis of the data from the blind tests, calibration services, technical consulting, and direct

traceability to NBS standards. Utilities repre- senting approximately 40 operating power

stations and four commercial laboratories

which provide radioactivity standards and

calibration services for the nuclear industry

already participate in the program. The cost

of participating in the program is approximately $10,000 for the first year. For fur- ther information or to enroll in the program,

contact David Harward, Atomic Industrial Forum, 301/654-9260. For technical details about the program, contact Daniel Golas. an AIF research associate at NBS,

301/975-5540.

OINT PROGRAM BEGUN ON

LINEWIDTH

NBS and VLSI Standards, Inc.,

of Mountain View, California,

have begun a joint research pro- gram aimed at developing the next generation of linewidth standards for the semiconductor fabrication industry. Linewidths are an important feature dimension on inte- grated circuits (IC's). They can be as small as 1 micrometer or below. Proper process

control requires the fabricator to be able to measure linewidths accurately, but the

problem is complicated because the

dimensions of these features are approaching the wavelength of the light used to measure them under a microscope. Deter- mining exactly where the edges of the lines are is particularly difficult. The best current

linewidth standards—sold as NBS Standard

Reference Materials—are for lines on the

photomasks used to make IC's and

depend on light transmitted through the

transparent photomask. (See article on page 15.)

. ENSORS FOR NUCLEAR

Hi

^

WASTE CONTAINER

^|||^ CORROSION EXAMINED

lJS Modeling and predicting the

^IferiP^ long-term effects of corrosion in proposed high-level radioactive waste

storage areas is the goal of a program

NBS is working on with the Nuclear

Regulatory Commission. NBS researchers

are studying pH sensors in simulated

environments to determine how well they

indicate corrosion processes in nuclear

waste containers. These sensors also are

useful for indicating possible corrosive

action by monitoring the pH of water- based fluids in deep-earth nuclear waste

storage vaults. NBS scientists are studying reactively

sputter-deposited iridium oxide, a thin-film material that shows promise as an effective pH sensor because of its ability to operate at high temperatures. This type of sensor also is desirable because its low

electrical resistivity and high corrosion

resistance eliminate some of the short- comings of other sensors.

In a concurrent effort, other NBS

researchers are evaluating data on corro- sion and leaching behavior of various

materials proposed for use in nuclear waste

containment.

OOPERATIVE PROGRAM TO

STUDY ELASTOMER BLENDS

ESTABLISHED

NBS and GenCorp, Inc., of Akron, Ohio, have established a

joint research program to develop quality control information for the manufacture of

tires and advanced elastomer products

made from polymer blends. GenCorp

researchers are synthesizing samples of butadiene polymers, copolymers, and other

elastomeric blends for examination of their microstructures by small-angle neutron scat- tering (SANS) at the NBS research reactor. The SANS technique, which uses low- energy neutrons as probes to measure the

structures of polymer chains in blends,

allows scientists to determine the phase

separations of molecules as a function of temperature and composition. SANS

measurements will be used by the re- searchers to develop phase diagrams that

will show the mixing and curing times

required to obtain specific properties in polymer materials. The joint project is part

of the NBS research associate program,

which provides an opportunity for people

from industry, universities, technical

societies, and other organizations to conduct cooperative research at NBS on proj- ects of mutual interest; salaries are paid by

the sponsor,

4
Riding a Heat Wave:

Researchers Take Another Look at

Superconductivity

^^ f /

Electronics engineer James Beall (left) and physicist Dr.

James Zimmerman adjust apparatus used with the hightemperature SQUID they developed and built. This SQUID

may be the first practical superconducting device to

operate in liquid nitrogen.

t's not much to look at, akin to a

fragment of charcoal. And it has

problems—lots of them. But, oh,

what a future this material has. The unglamorous black shard

NBS surface scientist Dr. Roger

Stockbauer held in his hand could

very well be the cornerstone of a

technological revolution. That pros- pect keeps Stockbauer and col- league Dr. Richard Kurtz up nights

working at their beamline on the

Bureau's Synchrotron Ultraviolet Radiation Facility-ll (SURF-II). Their

aim: to pin down the electronic structure of this compound of yttrium, barium, copper, and

oxygen. The information is essential

to determining why this ceramic

oxide and related compounds are superconducting at temperatures

that only months ago were dis- missed as unimaginably high for resistance-free conduction of

electricity.

"I can't see keeping away from

this," says Kurtz. "This is so hot

that I can't imagine anything else would be as exciting."

Surface scientist Kurtz is not alone in his enthusiasm. It is shared

by the Bureau's physicists,

chemists, ceramists, theorists, and

engineers—technical experts of virtually every kind that are involved in nearly 20 projects focused on trans- forming the newly discovered hightemperature superconductors from

laboratory curiosity to useful technology. In fact, the surprise

heat wave in the superconductivity

field has overtaken researchers

worldwide, including thousands in the United States alone. Many of these researchers

believe they are on the trail of materials that will allow resistancefree passage of electricity at room

temperature, as compared with

today's conventional, metallic superconductors that are bathed in expensive, cumbersome liquid

helium at 4 kelvins (minus 452 °F). The technological windfall would be

enormous—electric cars, devices

for storing electricity generated by

power plants during off-peak hours,

magnetic levitating trains that travel

at speeds of several hundred miles per hour, dramatically faster computers, and scores of other applications. But even if scientists do not reach their ultimate milestone of a room-temperature superconductor,

already available materials that are superconducting at temperatures

above that of liquid nitrogen (77

kelvins), a cheap coolant in wide

use, promise immense dividends.

The big questions, of course, are, can the new high-temperature

superconductors fulfill their technological promise and, if so, when?

The research program under way

at NBS laboratories in Gaithersburg,

Md., and Boulder, Colo., focuses

5
on helping U.S. industry tap the

vast commercial potential of the

unusual ceramics.

"The Bureau has been studying

and measuring the properties of superconducting materials for more

than three decades," explains Dr. Robert Kamper, director of the

Bureau's Boulder laboratories and

chief of the NBS Electromagnetic

Technology Division. "While the new materials hold great commercial promise, the superconductor

industry already registers annual

sales of about $200 million. The

measurement standards and

methods that support manufacturing and commerce in this industry were developed here. We also have developed several superconducting devices, including what is probably the world's largest working array of Josephson junctions—

series of 14,184 junctions that can

produce a precise 10-volt standard

of electricity.

"Our expertise and measurement

capabilities In areas crucial to exploiting this tremendous opportunity will support U.S. industry's

efforts to surmount the many obstacles that must be overcome before

the new high-temperature super- conductors can be put to practical use."

The Goals

The Bureau's program, which

includes formal and informal collab- orations with industry, universities,

and other government laboratories,

has three complementary aims:

Contribute to efforts to increase the materials' critical current density. For microelectronic uses, such as connecting

semiconducting chips in a computer, the materials must reliably

conduct currents of at least 100,000 amperes per square centimeter (A/cm2). Large-scale

applications, such as electric transmission lines, will require current densities of at least 1,000,000

A/cm2. Most studies of the hightemperature superconductors

report critical current densities of about 1 ,000 A/cm2.

While an overriding concern,

the current-density problem en- compasses many other difficulties. For example, events at grain

boundaries in these polycrystalline

materials appear to disrupt the

flow of superconducting current. NBS studies will focus on deter- mining and measuring the structural and electronic variables

responsible for superconductivity

at high temperatures, as well as

those that pose obstacles to achieving the desired critical current density.

Support development

of a theory to explain hightemperature superconductivity.

Intuition and trial-and-error methods

spawned the discovery that com- pounds made of almost any one of the rare earths, barium, and copper

oxide are superconductive at temperatures that only months ago

were deemed unattainably high.

Why particular blends of these

elements are superconductive is a

mystery, however.

Without a guiding theory,

researchers racing to overcome the

problems that beset the materials

already in hand and to develop

room-temperature superconductors

may find their paths blocked. In collaboration with scientists at other

organizations, NBS researchers are working to construct an encompassing theory that accounts for high-temperature superconductivity

To help make more cost effective and reliable superconductors, Dr. Stephen Freiman and his NBS colleagues are working to determine how processing procedures influence

their electrical, magnetic, and mechanical properties.
in the ceramic materials. Their

efforts are supported by other NBS

projects focusing on the materials'

structural and electronic properties.

Support development and

control of processing methods.

The new materials are ceramicsbrittle and extremely susceptible to

fracture. While some groups,

including those at NBS, have

fashioned the ceramics into discs,

thin wire, tapes, films, or other rudi- mentary shapes, questions about

fabrication techniques abound.

Even if researchers solve the

current-density problem and others,

the materials would have little commercial value if they cannot be

made cost effectively and reliably. At this stage, says Dr. Stephen M.

Hsu, chief of the Bureau's Ceramics Division, the priorities are "to understand what the material is, how it works, how to make it, how

to control it; to identify critical parameters; to develop measure- ments of these parameters; and to develop standards to help other

people make the material."

This fundamental information will support other NBS efforts that are

...the priorities are "to

understand what the

material is, how it worlds,

how to make it, how to

control it; to identify critical parameters; to develop measurements of

these parameters; and to

develop standards to help

other people make the

material."

focusing on thin films, which will be

crucial to the microelectronics

industry, and on the bulk forms that large-scale applications will require.

In practice, wires, coils, and other

bulk forms are made of combinations of materials—composites containing superconducting fibers

embedded in a matrix that compensates for structural weaknesses

and inherent instabilities in electrical current. Making a good composite,

however, requires evaluating the

performiance of the entire structure, not just the superconducting

fibers. NBS researchers will also

characterize the properties and per- formance of various candidate

composites.

Data for Industry

While the sights of most researchers in the vastly expanded field are set on discovering a superconductor that operates at room

temperature, NBS researchers cast themselves in an important supporting role. Explains NBS ceramist Dr. Robert Roth, who developed what

is perhaps the most comprehensive

phase diagram to guide preparation of the superconducting yttriumbarium-copper-oxygen material,

"We don't want to compete with

industry. We want to help them.

They want detailed and accurate phase equilibria and other information. We aim to supply data that are

useful to industry."

Companies such as IBM, AT&T,

and Westinghouse, as well as

the Naval Research Laboratory,

universities, and other institutions,

regularly send samples of their high-temperature superconductors

to the Bureau for careful characterization. Only from this type

of detailed evaluation will scientists get a fix on the combination of compositional, structural, and electronic attributes that underlie hightemperature superconductivity.

Currently, the compounds that have

created such a stir in laboratories

and board rooms around the world

are not much different from

alchemists' creations.

"Superconductivity is a macroscopic phenomenon that is the

product of many microscopic and

quantum phenomena," explains Dr. Alan Clark, of the NBS Electro- magnetic Technology Division in Boulder. In other words, there are

lots of measurements of physical

and chemical processes to be

done before researchers fully understand how and why the

ceramic oxides work.

Getting to the Heart of

the Matter

Since January, Clark and his col- leagues have been zeroing in on many of the subtle details that lie

at the heart of high-temperature

superconductivity. They began

with the lanthanum-bariumcopper-oxygen compound dis- covered last year by scientists at

"We don't want to

compete with industry.

We want to help them.

They want detailed and

accurate phase equilibria

and other information. We

aim to supply data that

are useful to industry."

the IBM Zurich Research Laboratory. Although it generated a

rather tepid initial response from a

skeptical scientific community, that compound, which is superconducting at 30 kelvins, is the source of the current frenzy in the field. When new materials—most notably the yttrium-barium-copperoxygen multi-phase compounds

discovered by the University of Houston's Paul C.W. Chu and

his colleagues—pushed the superconductivity temperature to nearly

1 00 kelvins, the group expanded its

efforts to describe various properties of the high-temperature

superconductors and develop

measurement techniques.
Using sophisticated instruments,

Clark and his colleagues make

accurate measurements of the

critical temperature (the temperature

at which electrical resistance

vanishes), the critical field (the highest magnetic field the material can

withstand without losing its superconductivity), the critical current (the

largest amount of electrical current the material can carry), the Meiss- ner effect (the expulsion of external magnetic fields), the energy gap

(roughly, the strength of coupling

between electrons that pair up to. form a superconducting current),

and many other properties.

One of the additional properties

is the Josephson effect, the resis- tanceless passage of current through a thin insulating layer that separates two pieces of superconducting material. In April, Dr. John

Moreland and Clark detected the

phenomenon in the yttrium-bariumcopper-oxygen material at liquidnitrogen temperature, an observation also made by teams in France,

at IBM, and in Japan. Computers

based on Josephson junctions,

envisioned since the discovery of the phenomenon in 1962, could

operate substantially faster than

today's supercomputers.

Measurements of the Josephson

effect and other properties are pro- viding clues that will help answer

the question foremost in the minds

of theoreticians: Why do the

ceramic oxides superconduct at such high temperatures? The prevailing BCS theory, which describes

the mechanisms responsible for the

absence of electrical resistance in metallic superconductors, may not apply to the higher-temperature

ceramic materials. According to the

theory, superconductivity arises

when electrons couple and then

travel in lockstep fashion, proceeding unimpeded. (In normal conductors, single electrons move ran- domly, banging into atomic nuclei and other electrons and creating

heat, or resistance.) In conventional

superconductors, phonons—essentially sound waves generated by

the back-and-forth movements of atomic nuclei in the crystal lat- tice—cause electron pairing.

Phonons may not be the key actors

in the high-temperature materials,

but, while some researchers argue

otherwise, the standard theory may

still apply, although with some yet- to-be-determined twists. "Our inclination is that the new

materials are BCS-type superconductors," explains Clark. "There

are indications that there is a very

strong coupling mechanism joining

the electron pairs together. But what that coupling mechanism is, we really don't know. You have some mechanism that's pulling the

two electrons together. Right now

it's up for grabs as to what that is." The enigma appears in measure- ments made with the "break

junction technique" devised by

Moreland at NBS. The method

involves placing a bulk sample of a superconductor on a microscope

slide and then bending the material

and the slide with an electromagnet

until the sample breaks, creating a

tunnel junction between the split ends. Electrons migrate across the

junction, creating a tunneling current that reveals characteristic fea- tures of the superconductor.

According to measurements

made with Moreland's method,

"Our inclination is that

tlie new materials are BCS-type superconductors," explains Clark.

the size of the energy gap in the

ceramic oxides corresponds to the values predicted by the BCS

theory. Some of the other laboratories doing tunneling measurements

have reported higher values. While

suggesting that the differences

require close study, Moreland says

he suspects that the other teams

measured two or more energy

gaps simultaneously, a hazard

posed by the extremely granular

nature of the materials. Moreover,

Moreland notes that energy-gap

measurements are sensitive to the

type of technique used, a problem now recognized by researchers.

In addition, the NBS group,

again using the break junction

method, found evidence for a

strong coupling mechanism, much

stronger than in metal superconductors. Since results from other

laboratories cast serious doubt on phonons as the electron-coupling

mechanism, NBS data may reflect the activity of plasmons, excitons, or other subatomic particles that are on the list of potential coupling

mechanisms. A clearer picture

may emerge from more detailed

studies at NBS Boulder laboratories and by researchers using neutron scattering techniques

in the NBS Gaithersburg

laboratories.

Current Problems

The ceramic-oxide superconductors also exhibit disturbing frailties. For example, measurements by

Drs. Jack Ekin and Ronald

Goldfarb, of the NBS Electro- magnetic Technology Division,

show that the critical current drops

off dramatically when exposed to magnetic fields only slightly

greater than the Earth's. In bulk

samples, the critical current in magnetic fields measuring 100 gauss is only one-hundredth the size of current in a field of 1 gauss. To be

useful as magnets, explains NBS

physicist Ekin, the ceramic oxides

will have to withstand fields of at

least 1 0,000 gauss.

Ekin, who specializes in measure- ments of critical current density,

hypothesizes that the extreme sensitivity of the new superconductors
to magnetic fields, as well as some

other sliortcomings, may stem from

the disordered arrangement of

crystallites, or grains, in the

materials. "Our data from studies of bulk polycrystalline samples and

IBM's work with epitaxial films," he

says, "suggest very strongly that the materials contain strong and

weak superconducting regions that are inherent features." Like a chain,

the ceramic oxides appear to be

only as strong as their weakest link. What the data indicate is that the

superconducting current flows in a

preferred direction, moving two- dimensionally rather than in three

dimensions as in conventional

superconductors. If the strong

regions are arranged in sequential

planes, Ekin speculates, the

superconducting current will flow

unimpeded from grain to grain. If it

is forced to jump to a plane above

or below, as by a perpendicularly

oriented crystallite, the current drops markedly.

The geometric orientation of crystals appears to be a key variable in increasing the critical current density. The success of IBM researchers

in constructing a thin film that passed currents of 100,000 A/cm^

at liquid-nitrogen temperature stems

from their ability to grow large

grains, which accommodated the

two-dimensional flow of electron

pairs. But can the same geometric

order be achieved in bulk materials, as would be required for magnets

and other large-scale uses? Ekin

believes so. In a recently published

paper, he proposed general guidelines for achieving the desired alignment of grains in bulk materials

made from powders. With samples

provided by collaborators from

Westinghouse, AT&T, Argonne

National Laboratory, and the Coors

Ceramics Co., Ekin will first test the

validity of the hypothesis that grain

orientation strongly influences criti- cal current density. If the hypothesis

Drs. Alan Clark (left) and ilohn Moreland use a break

junction apparatus devised by Moreland to make electron

tunneling measurements on the high-temperature superconductors. These measurements will help explain why the

materials become superconductors at high temperatures.

IS confirmed, he will move on to perfecting his proposed methods

for aligning the grains.

Another problem, common to all superconductors, is devising a method for "pinning" lines of magnetic flux that would otherwise drive

the superconducting current out of the material. "The supercurrent concentrates magnetic flux in regions we call fluxoids," Ekin

explains. "The compromise worked

out in present-day superconductors

is to build in metallurgical defects

that immoblize these magnetic-field

regions so that the rest of the

material is superconducting."

Whether the same flux-pinning

techniques will work in the hightemperature superconductors is unknown.

Also on the agenda of the

researchers in the Electromagnetic

Technology Division are measure- ments of the thermal properties of the ceramic-oxide superconductors.

Because heat is the bane of superconductivity, thermal conductivity

and other properties are important

processing and performance

variables. For composites, measure- ments of thermal properties deter- mine the volume of copper or other

matrix materials needed to conduct

heat away from superconducting

fibers and avert the runaway

spread of electrical resistance. The

researchers, who have made some

of the world's most precise measurements of stress effects, are

evaluating how stresses and strains

9
encountered during fabrication or in actual working environments will affect the material's performance.

Studying Thin Films

Facing many of tine same questions

and problems, another group of NBS scientists is investigating

methods for making thin superconducting films. Here, too, the

emphasis is on processing

variables. Fabricating thin films, however, introduces special problems, the result of the exacting

requirements for making inte- grated circuits and other

microelectronic devices. For example, the films must be of uni- form composition and quality,

which is influenced not only by

technique but by the surface

geometry of the substrate,

explains Dr. Richard Harris of the

NBS Electromagnetic Technology

Division. Harris notes that IBM's thin film was deposited on a strontiumtitanate substrate, which has

"interatomic spacings comparable

to the new materials." Capitalizing on the similarities in atomic

geometry, IBM researchers were

In May, the group made

what may be the first

practical superconducting

device operating in liquid

nitrogen.

able to create a uniform film that achieved the current density nec- essary for microelectronic applications. The accomplishment

showed that the desired current

density is an attainable goal.

One challenge now is to repeat this on a substrate of silicon, the build- ing block of conventional microelectronic devices.

In their thin-film work, Harris and

his colleagues are initially concentrating on techniques akin to the one used by IBM, in which yttrium

(or another rare earth), barium, and

copper are vaporized simultaneously in oxygen. The vapor is then

deposited on a heated substrate. An alternate method, one that is more complicated and more costly,

is molecular beam epitaxy. The

technique entails growing singlecrystal films, molecular layer by

molecular layer, on a crystalline substrate. "There is a lot of trial-and-error work going on right now," Harris

explains. "First, people will probably learn how to make a particular

technique work. Then they'll go

back to figure out why it works."

Applications for Superconducting Films

Once Harris and his colleagues

refine their technique for applying

thin films, they will move on to the

next step of exploring applications, an area where they have considerable experience. Since 1969, the

team has been building devices

that exploit the unique measure- ment capabilities afforded by super- conducting materials. These

devices include microwave mixers

that can detect single photons,

super fast analog-to-digital converters, and arrays of Josephson

junctions that convert a precise fre- quency to a precise voltage. In fact, the present voltage standard is based on a Josephson junction

integrated circuit made by this group with conventional superconducting materials.

In May, the group made what

may be the first practical superconducting device operating in liquid

nitrogen. Called a SQUID, for superconducting quantum inter- ference device, the simple instru- ment can measure extremely low

magnetic fields, as determined from

variations in radio-frequency impedance of a superconducting ring

containing a single Josephson

junction. Built by Dr. James A. Zimmerman, an NBS veteran

enticed out of retirement by the

superconductivity heat wave, the

SQUID was made with a sample of yttrium-barium-copper-oxygen

material prepared by colleagues Dr. Ronald One and James Beall, and

it operated at temperatures up to 81 kelvins, 4 kelvins above the temperature of liquid nitrogen.

One commercial application

Harris foresees for superconducting

films is as interconnecting strips

between integrated circuits in computers. Copper or aluminum wires now do the job, but resistance in the wire limits the overall speed of the computer.

Here, as in other uses envisioned

for thin films and bulk superconductors, the problem of achieving

good contacts arises. Heat buildup,

which can squelch superconductivity, is especially troublesome at connections between superconductors

or between superconductors and

other materials. Contacts will have

to be of extremely high quality,

Harris says.

Answering Processing

Questions

One of the paradoxes presented by

the high-temperature superconductors is that samples of the materials are easy to make—so easy that even high school students have

gotten in on the act. But it's the

quality of the samples and, ultimately, the quality of thin-film and bulk

superconductors that concern Roth

of the NBS Ceramics Division. "Just because you have a sample

doesn't necessarily mean that you

have a good superconductor or a good ceramic," he says. Anyone who has baked a cake

can understand Roth's point. Overlook important details in a recipelike the correct oven temperature,

baking time, or proportions of ingredients—and the result might
be edible, but certainly not the

appealing creation intended.

Roth's phase diagram of the

yttrium-based superconductor is the

ceramist's equivalent of a cake

recipe. It specifies the proper mix of ingredients—oxides of yttrium,

barium, and copper—and the

proper heating temperature and

time for making pure powder

samples of the superconductor. It also depicts the complex interac- tions among the starting materials

"By varying the amount

of oxygen in tlie material

by one part in seven,"

Rhyne says, "you can go

all the way from a semiconducting state to a

superconducting state."

as the temperature and ratios of the three oxides change. Deviate

from the recipe and you could get a mixture of four different compounds, including the superconductor, or the desired phase

could be absent.

The phase diagram is also an important starting point for other endeavors that are crucial to understanding the hightemperature materials and for applications. "What people want

to know is, at what temperature

and what composition is the

superconducting phase in equilibrium with liquid so they can make

some attempts at crystal growth,"

Roth says. "And they want to know the effect of liquid and other

compositions on making

ceramics." While many groups

are trying to grow large crystals of the superconductors, which would

especially benefit efforts to make

thin films, success so far has been

limited.

Preliminary results from Roth's

x-ray diffraction studies suggest

why. The studies show that the

superconducting compound does

not melt directly to a liquid of the same composition, resulting in the

formation of unwanted phases.

Another obstacle is posed by

changes in atomic geometry that occur as the superconducting

phase forms in the system. When

annealed in oxygen at 500 to 600 °C, the forerunner compound,

Ba2YCu306, oxidizes rapidly to form

the superconducting phase,

Ba2YCu307.

During the transition to the

seven-oxygen compound, according to neutron diffraction analyses

carried out by researchers in the

Bureau's Radiation Reactor Division

in Gaithersburg, the crystal symmetry of the material changes. Rather

than crystallites composed of unit

cells with two equal axes and a

third axis of a different length (tetra- gonal symmetry), the superconducting compound is composed of

crystallites having unit cells with

three unequal axes (orthorhombic).

"When the material goes through

this transition," Roth explains, "the

crystallites twin," a phenomenon

that distorts the arrangement

among the tiny grains and disrupts

formation of the uniform, repeating

array that characterizes a crystal.

"This complicates experiments in crystal growing," he says, "and

creates problems in measuring the

properties of these materials. This is what we're trying to sort out."

Ideally, efforts to grow crystals

could forgo the lower-oxygen com- pound and begin with the super- conducting phase. But that may not be possible. Roth speculates that the seven-oxygen compound is not

stable. "At least in practice, you

have to make the lower-oxygen

compound and then oxidize it," he

says.

BaO

1/2(Y203) Mol % CuO,

Phase diagrams provide blueprints for

ceramic processing. Sliown above are tlie

equilibrium phases in the Y203-BaO-CuOx

system in air near 1000 °C. The primary

phase field shows the range of composition

where crystals of the superconducting

phase can be grown.

Trying to overcome these difficulties. Dr. Stephen Freiman, also in the NBS Ceramics Division, is using

glass-type starting materials, rather than powders, to create crystals of the superconducting compound. "If you have a glass and can pour it you may have a way to make thin

films," explains Roth, who is doing

x-ray diffraction analyses of Freiman's materials. Much of the ongoing work in the

Ceramics Division is related to the

question whose answer will ulti- mately determine the commercial

future of the high-temperature

superconductors: Can materials of consistent quality be manufactured

economically? To answer that question, the division's research teams,

working with other NBS experts,

aim first to determine how processing procedures influence the

materials' electrical, magnetic, and

mechanical properties.

11
Drs. Roger Stockbauer (left) and Richard Kurtz are using

tiie Bureau's Synchrotron Ultraviolet Radiation Facility-ll

to study the electronic structure of the new ceramic

superconductors.

"Our work to date," says

Freiman, "has shown that the transition temperature, as well as the

percentage of a sample that undergoes the transition to the superconducting phase, is very sensitive to the temperature and environment

under which the material is sintered

and annealed. Achieving the necessary level of critical current density

in these bulk superconductors will be determined by our ability to

tailor their chemistry and microstructure." But achieving the desired critical current density will not remove all the hurdles that stand in the way of superconducting electrical transmission lines and other large-scale applications. "These materials are

relatively fragile, even in compari- son to other ceramics," Freiman

explains. "Their use in wires and

coils, for example, will require that we make them less susceptible to

brittle fracture."

Studying Structural

Details

Some of the puzzling structural aspects of the high-temperature

superconductors are coming under

the scrutiny of Bureau researchers

who are using neutron-scattering

methods. "Neutrons 'see' oxygen

atoms very strongly," explains Dr. James J. Rhyne of the Reactor

Radiation Division. This capability is especially important because the

oxygen content of the ceramic

oxides seems to underlie their high-temperature superconductivity. "By varying the amount of oxygen in the material by one part

in seven," Rhyne says, "you can go all the way from a semiconducting state to a superconducting

state." Working at the Bureau's re- search reactor with collaborators

from AT&T Bell Laboratories, Dr. Antonio Santoro and colleagues in the Reactor Radiation Division determined the positions of the

oxygen atoms in the basic units, or building blocks, of the yttriumbased superconductor. It turns out

that oxygen atoms can be absent

at specific sites. The basic units are composed of layers of copper

and oxygen atoms, barium, and

yttrium. Depending on the heat

treatment, the average number of oxygen atoms in a unit cell can

range from six to seven. As deter- mined by the NBS team and by

researchers elsewhere, the vacancies occur in one of the copperoxygen layers, forming a chainlike

sequence that may be related to the mechanism responsible for superconductivity.

The oxygen site in question "has a very large vibrational amplitude,"

Rhyne says, "and this might be

correlated with the fact that this is where the vacancies in oxygen

appear." This evidence, in turn, provides some support for phonons

as the electron-coupling

mechanism.

Using the method known as

inelastic neutron scattering, Rhyne

and his colleagues are mapping

the vibrational energies of the

atoms in several of the rare-earth superconductors and slightly dis- similar materials that are not super- conducting. "This tells us about the

forces involved in exciting given

atoms into discrete vibrational states," Rhyne says. "By measuring the distribution of energies, one hopes to get information about the

12
possible phonon mechanisms causing superconductivity,"

Many agents for pairing electrons

have been proposed, however.

Identifying the actual mechanism

will require "correlating a large mass of data gathered with various

techniques along with theory,"

Rhyne says.

Data for Theorists

With SURF-II and a vast array of characterization techniques at their disposal, Kurtz and Stockbauer, of the NBS Surface Science Division,

believe they can help pin down the answer, feeding important information about the materials' electronic structure to theorists. Results of experiments conducted so far testify

to the unusual nature of hightemperature superconductors. One

finding, supported by evidence

from other laboratories, is that the

overall electronic structure of the

materials apparently does not change as they become superconducting.

"We were hoping to see a large

change in the electronic structure as the material became superconducting, a change that could supResults of experiments

so far testify to the

unusual nature of hightemperature superconductors.

port a new theory," Kurtz says. "But we saw no change as we

cooled the sample and so cannot

rule out the old theory." Kurtz and Stockbauer, who col- laborate with colleagues from the

Naval Research Laboratory, have

used a method called resonant photoemission to identify the electronic states in the yttrium-based

superconductor, information that can be used to calculate the

energy bands in the compound.

According to the theory, electrons

in a solid can have a range of energies. If they know how elec- trons are distributed within different energy ranges, or bands, and how

easily electrons can travel between

bands, theorists can predict the

electrical properties of a material. "Theorists who try to calculate

electronic structure end up with

bands due to the different chemical

components (in the superconductor)," Kurtz explains. "They can compare directly their theoretical understanding of the material with our measurements."

Once again, experimental evi- dence suggests that the hightemperature superconductors

contradict the conventional wisdom.

"The calculations to date do not agree with what we're seeing,"

Stockbauer says. "So the theorists aren't quite on the right track yet, as far as understanding interactions

in the materials."

Formulating a Theory

The surface scientists' findings are

especially intriguing to theorist Dr. David R. Penn, a member of the

NBS Radiation Physics Division. To

Penn, the resonant photoemission

studies suggest that the interaction between electrons in the yttriumbased superconductor is much

larger than expected. If the force of the interactions between electrons

"is roughly the same as the width

of the band structure," Penn says, "then the band structure calculations aren't going to work well. The

question then is, what are the elec- tronic states of these materials?"

Supplied with data by Kurtz and

Stockbauer, Penn and Dr. Steve

Girvin, of the Surface Science Divi- sion, intend to use a technique

called "cluster calculations" rto inter- pret the confusing results of reso- nant photoemission experiments.

"We hope to be able to understand the chemistry of these

materials at a fundamental level,"

Penn says. Then there is the ever-present

question that dogs all theorists in the field: What causes electron

coupling in the high-temperature

superconductors'?' By Penn's

count, at least two dozen explanations have been proposed, includ- ing one he and Dr. Marvin Cohen,

a theorist at the University of Cali- fornia in Berkeley, are suggesting.

They postulate that the pairing

results from an electronic excitation, as observed previously in cerfain transition metals. More

important, evidence for the excitations, which Penn and Cohen

speculate are caused by two

vacant electron positions in the same atom, was found by Kurtz and Stockbauer in their photo

emission studies of the yttriumbased superconductor.

In rough terms, the theorists suggest that one electron polar- izes an atom, thereby attracting

the second electron to form a

pair. According to Penn, the

hypothesis is a variation of the

BCS theory. He and Cohen are now testing the validity of their ideas, using mathematical models.

"I would say that anything you

propose at this point is very far out, almost by definition," Penn says.

"In a month or two, we should

know whether our ideas are

plausible."

by Mark Bello Washington, D.C.-area Science Writer
President Reagan Announces

Superconductivity Initiative

n July 28, 1987, at the Federal

Conference on Commercial

Applications of Superconductivity,

President Reagan announced an

11 -point initiative to promote furtfier work in the field of superconductivity and to ensure U.S. readiness

in commercializing technologies

resulting from recent and anti- cipated scientific advances.

The superconductivity initiative includes both legislative and

administrative proposals. The major

legislative components would: (1) amend the National Cooperative'

Research Act to expand the con- cept of a permissible joint venture

to include some types of joint pro- duction ventures; (2) amend U.S. patent laws to increase protection

for manufacturing process patents;

and (3) authorize federal agencies

to withhold from release under the

Freedom of Information Act commercially valuable scientific and

technical information generated in government-owned and -operated

The Department of

Commerce will establish a Superconductivity Center

at NBS laboratories in

Boulder, Colorado.

laboratories that, if released,

will harm U.S. economic

competitiveness.

The primary administrative

proposals;

Establish a "Wise Men" Advi- sory Group on Superconductivity

under the auspices of the White

House Science Council to advise

the Administration on research and

commercialization policies.

Establish a number of "Superconductivity Research Centers"

(SRC's) and other similar groups

that would conduct important basic

research in superconductivity and

serve as repositories of information

to be disseminated throughout the

scientific community.

The Department of Energy (DOE)

will establish three SRC's, as well as a computer database. They are; Center for Superconductivity

Applications at the Argonne

National Laboratory; Center for Thin

Film Applications at the Lawrence

Berkeley Laboratory; Center for Basic Scientific Information at the

Ames Laboratory; and Computer

Data Base on Superconductivity at the DOE Office of Scientific and

Technology Information.

The Department of Commerce

(DOC) will establish a Superconductivity Center at the National Bureau

of Standards laboratories in Boulder, Colorado. The center will focus on electronic applications of high-temperature superconductivity.

The National Aeronautics and

Space Administration is establishing a coordinating group on superconductivity activities at its Office of Aeronautics and Space

Technology.

The National Science Foundation

(NSF) will augment its support for research in high-temperature superconductivity programs at three of its materials research laboratories. In addition, NSF is initiating a series of "quick start" grants for research

into processing superconducting

materials into useful forms including

wires, rods, tubes, films, and

ribbons.

The Department of Defense

(DOD) IS developing a multi-year

plan to ensure use of superconductivity technologies in military

systems as soon as possible. DOD

will spend nearly $150 million over 3 years to define the engineering

parameters of high-temperature

superconducting materials; develop

the required processing and

manufacturing capabilities; and

accomplish the necessary development, engineering, and operational

prototype testing of super- conductors.

Urge all federal agencies to implement quickly the steps

outlined in Executive Order 12591

designed to transfer technology

developed in federal laboratories

into the private sector and

encourage federal, university, and

industry cooperation in research.

Direct NBS to accelerate

its efforts to develop and

coordinate standards... in

the United States and

internationally....

Direct the Patent and Trademark Office to accelerate the pro- cessing of patent applications and

adjudication of disputes involving

superconductivity technologies

when requested by the applicants

to do so. Direct NBS to accelerate its efforts to develop and coordinate

common standards (for example,

measurement methods, Standard

Reference Materials, and supporting technical data) in the United

States and internationally for super- conductors and related devices.

Encourage federal agencies

to continue to reallocate FY 1987

funds into superconductivity basic

research, applied research in en- abling technologies, and prototype development. Agencies are

to place a high priority on this area in FY 1988 and FY 1989.

Request that DOD accelerate

prototype work in sensor, electronic, and superconducting

magnet-based military applications

and that DOC (NBS) accelerate

development of prototype devices

in detection and measurement of weak magnetic fields. Seek reciprocal U.S. opportunities to participate in Japanese

government-supported research

and development, including

superconductivity.
Life on the Edge:

Measuring Linewidths

The problem of how to

measure the width of lines

on a semiconductor

photomask is a classic

example of how NBS

responds to industrial

needs.

inewidth. A code word for one of

tfie perennial battlefields of the

highly competitive integrated-circuit

industry.

The National Bureau of Stan- dards produces new measurement

technology, and the story of the

development of a system for line- width measurement offers not only a textbook case of product development, but an insight into how this national laboratory works.

The widths being measured are

of circuit lines and other features on

the photomasks used to make the

electronic devices on integrated cir- cuits (IC's). These lines, and all other features on an integrated circuit, are small and getting smaller. Simple economics rule: The smaller

the IC's, the more you can make at a time, the lower the cost per unit. Today industry leaders are talking

in terms of dimensions less than 1 micrometer wide. A typical human

hair IS 75 to 100 micrometers wide.

The width of IC features is a

critical factor, because it is one of the smallest important dimensions

on the chip, the "minimum feature

size," the limit of the manufacturer's

ability to control the manufacturing

The problem came to the

attention of NBS researchers when a commercial

standards maker came to

the Bureau seeking measurements to check his

linewidth standards

against NBS standards.

process. Bad things happen when

feature size cannot be controlled. Conductive lines may overlap,

causing short circuits; they may be

broken or pinched ("mousenips,"

the trade calls it); IC's may not work at all; or, worse yet, they may

fail unpredictably in service.

In the early 1970's. the IC industry became aware that there was a

problem, somewhere, with the control of critical dimensions. Integrated

circuits were being made in a pro- cess akin to photography or litho- graphy. The various layers of the

circuit are defined by transparent

"masks," the equivalent of photographic negatives. Mask suppliers

and IC manufacturers couldn't

agree on their measurements of linewidths. The problem came to the attention of NBS researchers when a commercial standards maker came

to the Bureau seeking measure- ments to check his linewidth stan- dards against NBS standards. Dr. Diana Nyyssonen, of the original

NBS research team, recalls, "The

problem was that there were no NBS standards at those dimensions. In industry, everyone had

their own in-house standards, and

none of them agreed."

Bureau researchers found that they could not make the measure- ments at the required degree of

NBS scientists Carol Vezzetti and Sam Jones use a modified optical microscope linked to a data-collection computer to calibrate NBS photomask SRM's. It takes up to a

week to calibrate a single photomask—an automated

system under development will cut that down to a day.

15
-6-5-4 -3 -2 -1 0 1 2 3 4 5 6 DISTANCE IN MICROMETERS |

0.6 Mm

Typical data showing an image of reflected light from a sili' con dioxide feature on a silicon base demonstrates the

measurement problem. The indicated line edges are only

estimated. Based on the data, the left edge probably lies

somewhere between -4.5 and -1.5, but an accurate theoret

ical model is needed to say just where the edge is relative

to the complicated reflectivity curve.

accuracy because light diffracted around thie edges of the lines, making the image seen in the microscope different from the actual lines (see illustration). The pitch of a pair

of lines, the distance from the center of one line to the center of the other, could be measured

easily, but a measurement that depended on knowing exactly

where the edges of the lines were—either the width of the line or the width of the space between

lines—was impossible to make to any reasonable accuracy.

The obvious question to NBS

researchers was, "If things are that bad here, what is it like else- where'i'" They followed up with about a year's worth of interviews

with Silicon Valley firms and reviews

of published data. The problem was bad, and it was no secret. Industrial measure- ments were wildly inconsistent, with errors as great as 20 percent on

comparatively large 5-micrometer

lines. The popular theory was that there were problems with the optics

used to produce the masks and

IC's. That the problem might be in the measurement process rather than the production process had

not occurred to very many people.

In fact, the NBS team decided,

the problem lay with measuring the

width of lines on the IC photomasks. The diffraction effects of

light around the edges of the lines was sufficiently great that it was

largely a guess as to where the

edge was. Not surprisingly, different people made different guesses.

Once the true problem was in

sight, the next step was to define

it more exactly. The NBS

researchers worked closely with

their industrial counterparts to make sure that they had a firm understanding of the situation in the "real world." Lists of error sources were drawn up, and

mechanical and optical measure- ment experts at the Bureau

argued possible solutions. In the

end, a decision was made to create a new measurement

reference—an artifact that mimicked the photomasks used in industry.

The creation of a whole new

measurement system is a more

complicated undertaking than is generally appreciated, according

to Dr. Robert Larrabee, who now

manages this project for NBS,

"It's not enough to provide a good ruler," says Larrabee, "you

must understand the physical

effects that take place during

measurement, the interactions be- tween instrument and specimen—you must understand what

It IS that you are actually measuring. You must know how to cali- brate the instrument used to measure the reference standard.

You must be able to specify the

appropriate procedures and tools used in the field, so that the stan- dards will be used properly, as well as the type and size of errors to be

expected. And you must communicate these procedures and

requirements to the people who will be making the measurements."

Beginning in 1975, various

research groups at NBS attacked

these problems. Theoretical models

were developed, largely by

Nyyssonen, to explain how an

optical microscope would respond

to light diffracting around the edges

of a line on a photomask. Amazingly enough, considering the age

of optical science, this work

resulted in some fundamental dis- coveries in optics. Textbooks were

rewritten. Comparisons were made with

optical and scanning electron
microscopes: The latter were

rejected as the primary measure- ment tool because the interactions

between specimen and instrument were not understood as well as for optical microscopes.

A standard photomask was

designed using typical industrial materials and a pattern designed

for measurement purposes. A new

type of precisely controlled microscope stage was designed and

constructed. A photoelectric microscope system that partially auto- mated the measurement process was designed and built. Instrument

set-up and operation procedures were developed. A standard tech- nique, which would in time become

an ASTM voluntary industry stan- dard, was developed.

Throughout the whole procedure,

the research staff stayed in touch

with their industrial contacts, reporting progress and soliciting comments. "We had a mailing list of about 1,000 names," recalls Nyyssonen, "and every one repre- sented a personal contact by someone on the staff." By 1978, NBS had a photomask

linewidth standard ready for test marketing. As any good salesper- son knows, however, it is not enough to have a great product.

You must convince your customers

that they want it. A "round robin" of 10 companies, including IC manufacturers,

photomask makers, and instrument

makers participated in a linewidth

measurement trial using the prototype standard and their own measurement procedures. The reported

values for a line 2 micrometers

wide ranged from 1.5 to 2,5. This

helped convince people that there was a problem.

A year later, NBS issued the final design of its first linewidth standard

as SRM (Standard Reference

Material) 474. Because of the

painstaking calibration procedures

required to certify each copy, SRM

474 was the most expensive

reference standard ever produced

by NBS~$5,016 per unit. It was

issued With some trepidation, but

went to the best-seller list almost

immediately. Demand has ex- ceeded supply almost continuously

since the first announcement.

To provide customer support,

NBS instituted a series of "Linewidth Measurement Seminars,"

week-long programs conducted by

Nyyssonen and her staff, which

featured both lectures and "handson" use of the SRM. Recognizing

the importance of the new system,

photomask instrument makers

loaned commercial measuring

equipment to the seminars so

attendees could practice on the same microscopes they would use

at work. Almost every seminar was

booked up weeks in advance.

Information at these seminars

flowed two ways, according to Nyyssonen, "We would have feedback sessions at the seminars on what measurement problems the

participants were seeing in their work. Other than the visits to companies, I think the linewidth measurement seminars were our most

important source of information.

People were very open with us, taking us into their facilities to see

their equipment and discuss their problems."

By 1981, Bureau researchers were considering improvements.

SRM 474 was expensive largely

because it was complicated and

took a long time to certify. Discussions with industrial customers

revealed that most people really didn't need all the complexity.

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NBS 473

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5—:

10 2D 0

l-l 1

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iii1

The next NBS photomask reference standard will be NBS

473, shown here. It will include calibrated linewldths as

narrow as 0.5 micrometer (Instead of 0.9 micrometer) and

as wide as 30 micrometers (Instead of 1 0 micrometers).

The wider lines are used to calibrate oversized photomasks used in some facilities.

17
SRM 475 was designed, a simplified standard that could be certi- fied and sold for much less. (On

October 1, 1987, SRM 475 will be

priced at $3,781.) The NBS masks

used a dark chrome to reduce

reflections, but some customers

use bright chrome masks so a

bright chrome SRM was developed and will be released as SRM

476.

Industrial response was gratifying. In 1982, a U.S. firm, one of the world's largest IC manufacturers, formally instituted an in- house measurement system

based on SRM 474. "It has

basically become our bible,"

noted the linewidth measurement

project manager. "We've created a whole series of secondary stan- dards, sent them out to the 'front ends' and our measurement

squabbles have been cut by 90

percent. I can't remember the last time anyone tried to challenge our readings on a linewidth based on

our knowledge from your measure- ment seminars and SRM 474,

whereas that was a weekly if not

daily occurrence before then."

Another firm estimated in 1983

that it had invested about $400,000

in new measurement procedures

built around the NBS linewidth stan- dard and "bought that back many

times over" in reduced production

problems.

In 1982, NBS studied the impact

of the linewidth standard on the

semiconductor industry. A hypothetical company making $1 ,000

photomasks would save about

$179 per mask by using the NBS

technology, of which at least half the savings could be directly attri- buted to the NBS work. Implementation costs: $2 per mask.

On worldwide mask sales of $375 million per year, that translates to a $30 million savings

directly attributable to the NBS pro- gram, which costs less than

$400,000 per year. The numbers are to be taken

cautiously—too many estimates are

involved to be sure of the actual dollars— but almost every variation

in the basic assumptions resulted in significant economies.

Technology, of course, does not stand still and neither can a stan- dards laboratory. Today NBS is looking to the 1990's and a whole new set of linewidth measurement

problems. The current optical

system used to calibrate the NBS

linewidth SRM's is useful for line- widths down to about 0.5 micrometer, but manufacturers are beginning to think in terms of 0.1 -micrometer linewidths. Accurate

measurements at that level will require scanning electron microscopes, with characteristics quite

different from optical instruments.

"What happened in optics is what is happening now in scanning

electron microscopy," notes

On worldwide mask sales

of $375 million per year,

that translates to a $30

million savings directly attributable to the NBS program, which costs less

than $400,000 per year.

Larrabee. "People have instruments

and are making measurements that they believe are correct. When

things go wrong, they don't question the measurement, |ust the

results."

In addition, the present system

relies on measuring light coming

through a transparent mask. Industry needs a similar standard for measurements made on the

opaque semiconductor wafers

themselves, and this introduces a whole new set of problems. Imaging in reflected light can be more

complicated to model than imaging

in transmitted light, and the mathematical models developed for SRM

474 do not apply to features on

integrated circuits. NBS researchers are looking for solutions to these problems, working as usual with their privateindustry counterparts. NBS currently

has formal agreements for joint

research with several private firms,

including:

CD Metrology Inc., to develop

mathematical models to interpret

the profiles of features as imaged

by electron and optical microscopes;

EDAX International, to develop

linewidth calibration techniques for scanning electron microscopes;

n E. Fjeld Company, to develop

precision stages for SEM's;

C Hewlett-Packard, to develop

state-of-the-art masks for linewidth standards; and

VLSI Standards, Inc., for basic

research to model how light reflects from thick lines on silicon wafers. The linewidth standard is just one

of many measurement problems

studied at NBS, but it is an example of the way the system is sup- posed to work.

Comments NBS Director Ernest Ambler, "Behind each SRM. each

individual calibration, or each table

of reference data is a substantial investment in time and effort by our

best people. In this case, industry

thought that all they needed was

an SRM, but in fact they needed

an entirely new measurement

technology. We have the expertise

to know the difference and to solve

the problem, and it is our mission

at the National Bureau of Standards

to do so—it IS what we are all about."

by Michael Baum

NBS Public Affairs Specialist
Tliin-Film Thermocouples Designed

for Diesel Engine Research

ore efficient and longer-lasting

diesel engines may result fronn the

application of a novel type of device developed at the National

Bureau of Standards that monitors

critical internal temperatures of diesel engines.

Researchers at the NBS Center

for Chemical Engineering are experimenting with thin films of noble, chemically inactive metals

such as platinum and gold, which

are fashioned into scaled-down

thermocouples. Unlike traditional wire thermocouples, the thin films are deposited directly onto engine

parts and act as sensors to indicate

temperature at those points.

By having accurate temperature

measurements during operation of such diesel engine components as

valves, cylinder heads, and piston crowns, it is possible to monitor wear and tear of engine hardware

as well as provide input for controlling automatic engine functions

such as fuel-air mix and timing.

Temperature data also are important in the design phase of modern

ceramic-coated diesel engines. For example, knowing how hot the

combustion chamber of an engine

gets during operation allows design

engineers to decide how thick the

engine's insulating ceramic coating

should be or what porosity the

coating should have.

Much of the NBS work to date—

which is supported by the Department of Energy— has focused on

problems that interfere with successful operation of the films. One

of these has been a difficulty with

electrical shorts through the material

that insulates the film from the sur- face of engine parts. Poor adhesion

of the thin film to the insulator can cause difficulties as well. "We've made considerable progress in removing some of the problems that exist with thin films," says

Dr. Kenneth Kreider, chief scientist on the project. "For example,

we've developed a double-oxide

layer that includes a thermal oxide

and a sputter-deposited oxide

which have the best electrical insulating properties at 2000

degrees Fahrenheit." Kreider adds

that this material insulates platinum

and other metals at engine temperatures and provides improved

adhesion.

Thin films have many advantages

over traditional wire thermocouples.

These older devices— basically two

wires of dissimilar metals joined at both ends which indicate temperature by measurement of the voltage

difference between the two endstend to be cumbersome for diesel

The two discs at the top of

this sensor plug are part of a thin-film thermocouple

system that will accurately

measure the internal temperature of a diesel

engine.

engine applications. Because the

wire devices must be imbedded in machined grooves inside engine

parts, they create obstructions. This can lead to distortions in reproducing exact heat transfer conditions.

Thin films, on the other hand, use

the same principle as wire thermocouples, but typically are only 2

micrometers thick, so they do not

cause these interferences. Temperature measurements by means of voltage readings can be made with a voltmeter outside the engine, or perhaps in the future through a

readout on a vehicle dashboard.

Thin films have other advantages;

They conform to complex sur- faces, making them adaptable to a

variety of locations inside engines.

Multiple installation is easy and

inexpensive. Though metals like platinum and gold are used, such a

tiny amount is required, the cost is only about $2 per thermocouple.

Thin-film devices have fast response times.

Besides measuring temperature, thin films also indicate heat

transfer, or the amount of heat dis- sipated by engine operation. This is particularly important in developing

modern ceramic diesel engines—

which have no radiators— because

accurate heat transfer is the key to

efficient operation of these engines.

The NBS work, while showing

much promise in laboratory experiments, has moved closer to practical applications. Most notably, it has been used in a ceramic diesel research engine located at Purdue

University in Lafayette, Indiana. This

research, which is also sponsored

by the Department of Energy and

the National Aeronautics and

Space Administration, aims to develop a fuel-efficient, highperformance engine that could be

used in vehicles such as trucks,

buses, heavy equipment, and

even military tanks. Kreider also has assisted major

diesel engine manufacturers such

as Cummins, Detroit Diesel, and

Caterpillar, which are exploring how

they can use thin-film technology in

their products. For additional infor- mation, write or call Dr. Kenneth

Kreider, B312 Physics Building.

NBS, Gaithersburg, MD 20899,

301/975-2619.

by John Henkel

NBS Public Affairs Specialist

19
Concrete Research at NBS:

New Ways to Understand an Old Material

Pliny's Recipe For

Good Concrete

Five parts sand

Two parts quicklime

Fragments of volcanic rock

Just enough water to blend

Mix well, and for best results, let bake in thie Sun for several hundred years.

ith a dash of creative license added, this IS one of the earliest known

"recipes" for concrete. It was

recorded by Pliny, a Roman naturalist and writer, in the first century A.D. The Romans were master

builders who used concrete in innovative ways to build bridges,

coliseums, temples, and even

apartment complexes. But, of course, they had very little scientific knowledge of the material they so

skillfully used.

Dr. Leslie Struble uses a

cylinder and piston device

to study the causes of con- crete failure.

In some ways, not a lot has

changed. For the most part, concrete IS still made with similar basic

ingredients—a bonding material

(the Romans used quicklime, today

It IS usually portland cement), an aggregate like sand or gravel, and

water. And, despite its great impor- tance and long history as a build- ing material, much is still not known

about the behavior of concrete or the factors which control its strength

and durability.

In the United States alone,

billions of dollars are invested

annually in millions of tons of concrete used to build skyscrapers,

highways, dams, and bridges. But many of these concrete structures are deteriorating years before they

should, says a recent National

Research Council report. The bill for replacing and repairing existing concrete structures is estimated at several hundred billion dollars. Future maintenance costs for similar structures could be radically

trimmed if currently available

technologies were used on the construction site, the Research Council

committee contends. Furthermore, if new ways to make concrete more

durable were applied, even greater

savings could be realized, the

report says. Changes are on the horizon,

however. "Within the next decade,

concrete will be more predictable as well as stronger and more

durable," says Dr. Geoffrey

Frohnsdorif, chief of the Building

Materials Division at the National

Bureau of Standards.

Using computer technology combined with sophisticated techniques

such as electron microscopy and

computer image analysis, re- searchers in the NBS Center for Building Technology are among a

small group of scientists worldwide

who are ushering in these changes

by learning more about the science

of concrete. This research will form

the basis for new techniques and

tools which can help predict the

performance, strength, and durability of concrete based on its composition.

Getting Down to Basics

At the heart of the NBS research

are studies on the chemistry and

physics of concrete. Concrete does

not harden by drying, as is often thought. It hardens because of a complex set of reactions in which

the water and cement combine

This research will form

the basis for new techniques and tools which

can help predict the performance, strength, and

durability of concrete

based on its composition.

chemically to form new compounds. Initial setting may take a few minutes or several hours. But

this whole hydration process continues for months and even years as the material continues to gain

strength.

Dr. Paul Brown, a materials

scientist at NBS, is developing a computer model to simulate hydration of Portland cement. Understanding this process is important,

says Brown, because it is hydration

that controls how the internal struc- ture of concrete—called the micro- structure— is formed.

As with other materials, it is the

microstructure that ultimately deter- mines the characteristics of concrete, such as strength and

durability. Just how these characteristics are linked to the microstructure IS still uncertain, however.

NBS materials scientist Dr. Hamlin

20
Jennings is developing a computer

model which will correlate information on hydration and microstructure with physical properties and

ultimately with performance.

"Once you've got the rules right

the model can be used in a number of ways," says Jennings,

"such as predicting how a parti- cular mix of concrete will behave

in the environment and the structure. It could also be used as a teaching tool." He believes the

model will serve as a prototype to simulate the development of microstructure in other materials

such as ceramics.

Basic research helps the NBS

scientists understand why struc- tures fail. A reaction that sometimes occurs between dif- ferent compounds in hydrating

cement and in the aggregate causes the concrete to slowly

expand and crack, and ultimately

may cause the structure to fail. "It

IS an expensive problem that is particularly troublesome for struc- tures, such as dams or bridges,

that you expect to last for a long

time," says Dr. Leslie Struble, an NBS materials research engineer.

Struble is studying the reaction to better understand the mechanisms by which it occurs, "If we

know how and why the reaction occurs we stand a better chance

of developing ways to prevent or

control it," she says. The NBS research team also is studying the scientific aspects of a

recent development in concrete

technology. Typical ready-mix concrete can support loads of 3,000 to 5,000 pounds per square inch (psi). But, scientists believe concretes

with strengths of 30,000 psi or more can be achieved by mixing

chemical or mineral admixtures in with the other ingredients. But like other new products, a

lack of standards and experience

with these admixtures presents certain problems, says Frohnsdorff.

According to the National Research

Council report, the development of tests for determining long-term

durability has not kept pace with the development of new materials. One of the biggest problems is the

need for quality control standards

for evaluating mix design and per-

"If we know how and why

the reaction occurs we

stand a better chance of

developing ways to prevent or control it."

formance of high-strength concrete.

In many cases, guidance from

industry groups is not yet available

and equipment in some testing

laboratories is not sufficieni for measuring the strength of these new materials. Says Frohnsdorff, "Using admixtures to achieve stronger concretes

is a great advance in concrete

technology. But we lack a fun- damental understanding of how

they work." The NBS research

team will be studying the factors which control strength develop- ment. Their research will form the

basis for test methods and stan- dards for evaluating the perfor- mance of high-strength concretes,

adds Frohnsdorff.

Better Tools

In addition to these longer-term,

fundamental studies, NBS re- searchers are developing tools to help industry better control the per- formance of concrete.

In conjunction with the American

Concrete Institute (ACI), Dr, James

Clifton, NBS research chemist, is designing an easy-to-use "expert

system" to help builders get advice on selecting constituents for durable

concrete. The system is a computer

program that uses facts along with

the judgment of experts from ACI. The NBS system—called DURCON,

for DURable CONcrete—asks a

series of questions, such as "Will the concrete be used indoors or ouf^" "Will It be exposed to moisture?" "Will reinforcing steel be

used?" Based on the answers, the

program will recommend an appropriate mixture of materials. Drs. Nicholas Carino and Mary

Sansalone, NBS civil engineers, are using an old technique in a new

way to find flaws in concrete. Known as "impact-echo," the

technique works on the same principle as the sonar pings used to locate and determine the depth of a submarine. An impact on the

concrete generates sound waves

which are reflected by flaws inside

the concrete. A receiver mounted

on the surface of the concrete

picks up the reflections, or echoes.

The location of a flaw is determined

by measuring how long it takes to receive the reflected echo. "The

technique can be used in either plain or reinforced concrete to determine where flaws are and to estimate their sizes," says Carino,

Although more work needs to be

done, Canno and Sansalone feel the research will soon form the

basis for a simple, easy-to-use

method that will be used routinely

to evaluate concrete.
Drs. James Clifton (standing) and Hamlin Jennings discuss

a computer model which will help correlate information on

hydration and microstructure with the physical properties

of concrete and, ultimately, its performance.

Determining Strength

Another area being studied by NBS

will give builders more confidence

in determining when newly placed

concrete is strong enough for the

construction formwork to be

removed. Says Dr. H.S. Lew, NBS

research structural engineer. "A

builder wants to remove the formwork as soon as possible so he can get on with the building. But he doesn't want to risk the safety of the construction workers." Lew and

several coworkers have developed

a method based on statistics for analyzing field tests used to measure the in-place strength of concrete. This new method is more

accurate and reliable than those

currently being used in the industry,

says Lew. The procedure has been

programmed and can be used on

a personal computer, he adds. The

American Concrete Institute is incorporating the method into its standard practices.

Strength is also a major

consideration when designing concrete structures to resist earth- quakes. NBS researchers recently

completed the first full-scale laboratory test in the United States

of a concrete bridge column subjected to earthquake-like stresses. A second column is being fabri- cated at NBS and testing is scheduled to begin soon. "This work

will give us firsthand knowledge

of how very large concrete struc- tures perform during earth- quakes," says Dr. Charles Culver,

chief of the NBS Structures

Division. A companion series of tests on

six smaller versions of the col-

'This work will give us

firsthand knowledge of

how very large concrete

structures perform during

earthquakes."

umns has been conducted to determine if research on small specimens can be extrapolated to the large sizes. The National

Science Foundation, Federal

Highway Administration, and Cali- fornia Department of Transportation are lending support to this

project.

The challenges and difficulties in making concrete more predictable

and improving its strength and

durability are great, agree most

experts. But, says Frohnsdorff, the

future has never looked brighter.

He says, "Thanks to computer

technology and advanced re- search, we are filling gaps in our knowledge of cement and concrete and are making strides toward

stronger, longer-lasting materials."

by Jan Kosko

NBS Public Affairs Specialist
Improved Clinical Lab Tests:

Goal of Cooperative Program

(From left) Drs. Polly Ellerbe, Michael Welch,

and Harry Hertz pose beside laboratory

equipment used for making extremely

accurate measurements of blood cholesterol

levels.

reference laboratory program,

which initially aims to improve

clinical measurements of blood serum cholesterol levels and drugs

of abuse in urine, has been established by the College of American

Pathologists (CAP) and the National

Bureau of Standards.

Based at NBS headquarters in Gaithersburg, Maryland, the pro- gram is the latest chapter in a

nearly 10-year association between

NBS and the 10,450-member CAP.

Both organizations have observed

significant variances in test results among different clinical laboratories

and have worked together since

1978 to help improve these often

critical measurements.

Much of the time NBS and CAP

have spent working together in the

last decade has been devoted to perfecting definitive analytical measurement techniques such as the use of isotope dilution mass spectrometry. Working side by side with

NBS researchers, CAP-sponsored

scientists have used these definitive

techniques to certify the accuracy

of serum samples sent to laboratories as part of the CAP Surveys

Program. This program, in which

clinical laboratories nationwide are

periodically asked to analyze serum

samples and report their values to CAP, IS a barometer of how well labs are performing clinical tests. The new reference laboratory

program expands the earlier joint

agreement and places special

emphasis on development of affordable clinical reference

samples that laboratories can buy

and use to check or improve their measurement reliability. One area of great concern as the new program gets under way is the

accuracy of cholesterol tests in

clinical laboratories. Though the

links between high blood cholesterol amounts and heart attack risk have been demonstrated, there is currently no guarantee that a single

blood test will yield an accurate pic- ture of an individual's cholesterol

level. A 1985 CAP survey, in which

identical serum samples were sent

to several thousand clinical laboratories for cholesterol analysis, con- cluded that about half produced

results that were insufficiently accurate to meet new cholesterol measurement goals. For patients, imprecise measure- ments can have serious conse- quences. If cholesterol amounts are measured falsely to be high, a per- son could be placed on medication, with its potential side effects, when diet and exercise may be all that are necessary. Conversely, a

false low reading might cause a

patient's cholesterol level to be

overlooked when it needs attention. Though improving the track

record of some laboratories will not be an easy task, the CAP/NBS

reference laboratory program is a

big step in the right direction, says

CAP President Robert L. Breckenridge. "We established the

program with NBS to combine the

reputation and capabilities of NBS

in measurement science with CAP's

influence in the clinical community,"

he says. "Our aim is to produce

reliable methods and materials for

clinical laboratories, but that alone

is not the answer. Labs must voluntarily use these aids before they can do any good, so we are getting the word out about the

benefits." The first product from the new

collaboration will be a kit of freeze- dried human serum reference

materials certified for high, average,

and low cholesterol concentrations.

It will sell for $42.50 and include six

vials of serum (two samples of each

concentration).

Because these materials are certified to be accurate, clinical laboratories can use them as "yardsticks"

to measure the reliability of their cholesterol measurements and

methods. The freeze-dried serum

can be reconstituted into a liquid

and run through the same procedures as a patient's sample.

Scientists in the reference laboratory program also plan to develop

a series of reference materials that would check the accuracy of urine

drug testing methods and equip- ment. One proposed material is freeze-dried urine certified for the

concentration of benzoylecgonine,

the principal urinary metabolyte of cocaine. The material will be

prepared by CAP and certified by

NBS, and additional drugs-in-urine

reference samples should follow. NBS and CAP also emphasize

that although these reference

materials could be used to check

the accuracy of commonly used

screening tests for drug abuse,

they are mainly intended for the more sophisticated analyses often

relied upon to confirm screening tests that produce positive

results. J.H.

23
Emerging Technologies:

Tlie Competitive Edge of the Future?

The following text is adapted from

remarks made by Deputy Secretary

Clarence J. Brown at a press brief- ing June 9, 1987.

t is no secret that this country has a

trade problem. Likewise, it is no

secret that at least part of the problem has been our inability to take

full commercial advantage of scientific and technological developments made in the United States. Time and time again we have seen

foreign competitors, most notably,

but not exclusively, the Japanese,

turn our technological developments into their commercial product

successes.

I think It IS fair to say that the

country has awakened to this dilemma. The national attention to the general subject of competitiveness is evidence of our awakening. The President has put

forward a comprehensive package

of proposals to deal with this problem, and the Administration is tak- ing a series of steps to improve our

situation.

I want to take a longer view of our trade and technology position. I want to draw attention to the future and to the technologies that just now are emerging from the laboratory and seem particularly promising in both a scientific and

commercial context. I am firmly

convinced that America's ability to exploit a new set of emerging

technologies with huge market

potential in the year 2000 and

beyond will play a big role in deter- mining the country's economic suc- cesses or failures well into the next

century.

Recognizing the importance of these technologies, I asked a group

of technical experts and top officials from Commerce Department agencies to examine the latest scientific and technological advancements

and to report to me on which

technologies seemed especially

important, what barriers stood in the way of their commercialization

within the United States, and what

steps could be taken to remove

those obstacles.

...America's ability to exploit a new set of emerging technologies with

huge market potential in

the year 2000 and beyond

will play a big role in determining the country's

economic successes or

failures well into the next

century.

This group, headed by NBS

Director Dr. Ernest Ambler, studied

scientific and industrial plans and

the commercialization process here

and abroad. They identified 17

emerging technologies in 7 major

groups which are expected to lead

to new products or processes in the future. Among other things, the

review panel considered the

expected contribution of each

technology to the gross national product.

The major technologies identified by the group are: advanced

materials, electronics, automation.

biotechnology, computing, medical

technology, and thin-layer technologies. (See detailed table on pages

26 and 27.)

This list is not meant to be cast in concrete. For example, since the

original list was put together, there

have been significant and highly

publicized breakthroughs in the

development of superconductors—materials that have absolutely no electrical resistance. (See article on page 5.) Basic scientific questions and great technical problems

need to be solved before we can

realize the economic potential of these high-temperature superconductors, so for now they must

remain a potential emerging

technology. But all you have to do is to look

at one possible application for these superconductors, the trans- mission of electrical energy, to

realize the enormity of their promise. We now spend $160 billion a

year on electrical power in this country, and we waste a full 20

percent of that power due to losses

in transmissions. If high-temperature

superconductors can be developed

to the point where they can be

substituted for conventional electrical transmission wires, we could save more than $30 billion a year. When I talk about the potential

of emerging technologies, that is what I am talking about, a revolution that could affect every industry

in America and around the globe. But there are some familiar barriers

to achieving maximum economic

benefits from emerging

technologies.

The relatively high costs of capital

funds and the less favorable tax
incentives in the United States compared to foreign competitors

top the list. Management's focus on short-term, rather than longer

But there are some familiar barriers to acliieving

maximum economic benefits from emerging

technologies.

range, goals for returns on invest- ments combined with poor inte- gration of manufacturing, design,

and research and development

functions within U.S. firms and the

lack of cooperation among

American institutions hurt our chances of exploiting emerging

technologies.

So do inadequate laws, regulations, and enforcement protecting

intellectual property rights in the

United States or overseas. Complacency and a dependence on

the domestic market—the lack

of awareness of the need to compete with Japan and other countries head-to-head in the

international marketplace—are a

basic stumbling block.

Restrictive trade policies in foreign markets; federal or state regulations on corporate activities; export controls on advanced

technologies and high-technology

products; restraints and uncertainty

caused by product liability and tort

laws; and anti-trust restrictions— real and perceived—against cooperative

ventures for R&D, marketing, or production are all formidable barriers to the commercialization of these emerging technologies.

Now, what do we do about

breaking down these barriers? Our

recommendations include:

Continued vigilance to reduce

federal budget deficits and to avoid

high interest rates which affect the cost of capital.

n Creation of venture capital

pools at the state and local levels. Additional tax incentives and

other actions to increase aggregate

savings.

A commitment to making

future changes in the tax laws

focus on the incentives available for modernization investment in all stages of production, marketing,

and distribution. Fostering participative man- agement by employees.

Training managers in the pro- duction process and updating

business school curricula. Eliminating provisions in foreign tax laws and regulations

that discriminate against U.S. products.

Improving export controls,

reforming product liability and tort laws, and lifting antitrust restrictions.

In a recent hearing before the

Committee on Commerce, Science

and Transportation, Senator Fritz Hollings complained, "America may

still invest enough in research to win most of the Nobel Prizes, but

the Japanese make all the profits on them." Well, we cannot let that continue to happen. As you can

see by looking at the barriers and

recommendations for commercializing emerging technologies, the

government has an important role to play. But the private sector—the

people who work in and run America's factories and board

rooms—must take the lead. This country has done enough

looking back and talking about how

many different areas of technology

we have already lost to the commercial competition. Our look

ahead at critical emerging technologies should be a warning that unless we pull together and take

swift action now to break down the

barriers to the commercialization of new technologies, we are going to be facing the same international trade problems we confront today

right on into the next century.

We have made some progress. Although we neither talk nor read

..the private sector—the

people who work in and

run America's factories

and board rooms—must

take the lead.

enough about them, this country

has some wonderful success stories and some good things happening

to show that businesses and even

entire industrial sectors can and are

taking decisive actions to improve

the situation. We have firms joining

together in research consortia, cor- porations cutting down on

excessive managerial positions,

companies finding new market

niches overseas. We simply must

be vigilant and make additional

changes now if the country's

economic future is to be bright

when the new century arrives.
Emerging Technologies

Technology

ADVANCED MATERIALS

Ceramics (highperformance structural and

electronic ceramics)

Polymer Composites (highstrength, fiber-reinforced

plastic resin)

Metals (rapid solidification,

metal matrix composites)

ELECTRONICS

Advanced Microelectronics

(enhanced VLSI and VHSIC

chips)

Optoelectronics (optical

fiber and light wave

processing)

Millimeter Wave

Technology

AUTOMATION

Manufacturing (computerintegrated and flexible systems)

Business and Office

Systems (computer

applications within an

organization)

What does it do

new or better?

Better high-temperature

strength-to-weight

properties

Better dielectric and

optical properties

Higher strength-to-weight

ratio

Design flexibility because

of spatial asymmetry

Improved strength and

high-temperature

performance

Improved magnetic

properties

Improved performance in speed and size

Improved magnetic

properties

Higher efficiency

photovoltaic conversion

Improved performance in speed, size, capacity, and

security

Higher density information

storage

When replacing radio

systems it frees RF

spectrum for other uses

Flexible reconfiguration of production processes

Integrated control of all production operations

Efficient information

storage, retrieval, and

exchange

Applied to what

products or processes?

Heat engine components,

turbine blades, heat shields

Electronic substrates,

integrated optics

Structural components

Structural components

Structural components,

superconducting

components

Electromagnetic

equipment

Semiconductor devices

Information storage

Solar cells

Electronic equipment,

information processing

Computer systems of all sizes

Voice and data

communication systems

All manufacturing

processes

Used by what

major industries?

Automotive and aircraft engines

Electronic components

Aerospace, automotive,

industrial construction

Aerospace, automotive,

industrial construction

Manufactured components

Electrical machinery

Electronic and optical

components and systems

Information processing

Energy generation

Communications,

computers

Computers

Telecommunications

carriers, corporate use for private circuits

All manufacturing

Networking, word All organizations

processing, database

management
Technology

What does it do

new or better?

Applied to what Used by what

products or processes? major industries?

Technical Services

(computer applications in

tlie provision of

commercial services)

Efficient high-volume

information storage,

retrieval, and exchange

Information retrieval and

distribution, database

management, education

and training

Financial services,

electronic mail,

telecommunications,

professional service

BIOTECHNOLOGY

Genetic Engineering

(design and production of

flighty selective agents)

Improved diagnostic and

therapeutic drugs

Improved plants,

pesticides, and animal

supplements

Neutralize pollutants

Health services

Foods, pesticides

Environmental control processes

Medicine, pharmaceuticals

Agriculture, food

processing

Chemical manufacturing

and treatment

Biochemical Processing Improved control of chemical processes,

outputs, and yields

Chemical separations and

reactions, biosensors

Chemical manufacturing

COMPUTING

Computing Equipment

(supercomputers, parallel

processing, computer

architecture)

Faster, lower-cost

computing

Artificial Intelligence

Techniques (includes

expert systems, natural

language, robotic control)

Improved computer

replication of human

judgment

Information processing,

computer control

Potentially all

Information processing,

computer control

All applications using

computers

MEDICAL TECHNOLOGY

Drugs (other drugs are included under

Biotechnology)

Improved immunology and

treatment

Health services Medicine, pharmaceuticals

Instruments and Devices

THIN-LAYER

TECHNOLOGY*

Surfaces and Interfaces

Improved diagnostic and

therapeutic systems

Improved control and yield of chemical reactions

New electronic and optical

properties

Magnetic resonance

imaging, CAT scanning,

radiation treatment

Chemical catalysis

Semiconductor devices,

surface modification and

coatings

Medicine

Chemical manufacturing,

food processing

Electronic components,

computers

Membranes New chemical properties,

better chemical separation

techniques

Chemical separations Chemical manufacturing,

food processing

•Semiconductor applications also are included under Electronics.
High-Technology Bugs Are New Tools

for Science and Industry

hen Drs. Frederick E. Brinckman

and Gregory J. Olson tell people

that they work with high-technology

bugs, most people probably figure

their research involves electronic

listening devices. !t doesn't. Research chemist Brinckman and

microbiologist Olson, with the

National Bureau of Standards, are working with more traditional types

of bugs^living microorganisms—

that can be put to use producing new, advanced materials for electronics, aerospace, and other hightechnology products.

Medical researchers have been

studying disease-producing viruses

and bacteria for more than a century, and for the last 20 or 30 years

scientists have been able to identify some of the microorganisms that feed on minerals locked in ore

deposits. But It is only recently that

scientists have paid much attention

to the potential for putting these

bugs to work in processing

materials. "These tiny microbes are found

all over the Earth, from the tops of mountains to the bottom of seas, and they even thrive at pressures

and temperatures that are hostile to

all other forms of life," says Olson,

"With advances in science, we now

know that microorganisms have

been processing materials for about

3.5 billion years."

Examples of this natural biogenesis include minerals containing such

elements as iron, manganese,

magnesium, silicon, and calcium

produced by a variety of microorganisms that include bacteria,

algae, and protozoa. For instance, some of the Earth's deposits of calcium compounds are made by

the accumulation of shells from simple invertebrate organisms.

Brinckman, head of the project, says, "There are tremendous

opportunities for harnessing

microorganisms in various bioprocessing technigues. They also can play an important role in the

recovery of our planetary

spaceship's limited supply of scarce elements from wastes." Because microorganisms can be

used to produce very pure

materials of specific composition as

well as to recover others, scientists

at NBS are working to develop the

basic measurement tools industry

and government will need for several new bioprocessing

technologies.

The )ob IS difficult, the scientists explain, because microorganisms

behave in a variety of ways: Dif- ferent strains do different things.

There are organisms with appetites

for certain minerals. Others are able

to detoxify heavy metals such as mercury, and some can oxidize

insoluble materials to unlock ele- ments that are bound into them.

Still other organisms secrete com- pounds to trigger various chemical

and biological processes, some of which lead to corrosion.

Perhaps one of the most potentially useful groups of microorganisms for industry are those that feed on metal ores to obtain their energy for survival. They can be

used in bioleaching methods that have been shown to be more

economical and less polluting than

conventional technigues used to extract minerals such as smelting.

While these organisms do not

ingest metals, they release material

bound into ores so that it can be

flushed out and collected. These

microorganisms currently are being

used to remove copper and

uranium from low-grade ores on a

large scale.

Pilot plant studies show a dra- matic increase in the yield of gold

from pyrite when organisms are used in a preleaching step to dis- solve the tough pyrite matrix that shields the metal from extracting

chemicals.

There are even microorganisms

that thrive on metallic ions and toxic

substances in water. They can

accumulate up to 50 percent of

their weight with other materials

and be used in various bioaccumulation methods to purify water by

absorbing dissolved metals and

breaking down solid wastes. The NBS scientists explain that progress in harnessing microorganisms IS inhibited by incomplete

knowledge of various metabolic

processes. For example, many

organisms can be found in ore

deposits. The guestions are. which ones are best for carrying out different processes, what fac- tors limit their reaction rates, and

how can industry manipulate the

various environmental conditions

such as light, oxygen, moisture, or temperature that are reguired for organisms to do their work?

"These are a few of the great

unknowns at this point,"

"There are tremendous

opportunities for harnessing microorganisms in

various bioprocessing

techniques."

Brinckman says. "And this is where NBS can help industry by

developing standards and proce- dures for the bioprocessing of materials."

Cooperative Efforts

Bureau scientists are looking at a number of measurement tools and

technigues. These might include

certified samples of ores for conducting standardized tests to identify preferred strains of organisms

and bioprocessing conditions.
Drs. Gregory Olson (front) and

Frederick Brinckman work with a

microscopic Fourier-transform

infrared spectrometer to ciiaracterize nondestructively the sur- face of materials undergoing bioprocess.

In another cooperative effort pro- posed withi the Electric Power

Research Institute, Bureau re- searchers plan to explore the use

of microorganisms in coal-cleaning

processes to reduce the fuel's sulfur content. Various types of organisms might be grown in hightemperature bioprocessing reactors

at Johns Hopkins University and at NBS to determine which ones can be used to remove sulfur. This

research also may examine the use

of organisms as measurement tools

to identify certain forms of sulfur in coal.

In joint efforts at NBS and Johns

Hopkins University, scientists are studying the metabolism of bacteria

attached to ore surfaces. By color- ing the organisms with stains and

using a microscopic fluorescence

imaging technique, the researchers

are able to monitor the activities of bacteria by cell color. This information will be used to develop

measurement standards for controlling organisms in bioprocesses.

Bureau scientists also are helping

the Office of Naval Research to evaluate the potential use of microorganisms to recover strategic

materials such as cobalt, chromium,

and nickel from smelter wastes. Microorganisms also could be used

to extract these materials from

domestic low-grade ores.

In another project for the Navy,

NBS researchers are evaluating the

performance of coatings for ship

hulls that contain tributyltin to pre- vent the growth of algae and bar- nacles. Even though this project is aimed at preventing fouling which

is costly to remove, the control of microbiofilms on surfaces may lead

to new protective coatings.

In another effort, the NBS scientists are consulting with the Air Force to evaluate techniques in which microorganisms are used to recover gallium from domestic lowgrade ore deposits to improve the

supply of this largely imported

material for high-technology

electronics. NBS scientists also participate in technical symposia and consult with a wide group of industry associations, universities, and government

agencies which have a growing

interest in microorganisms to proc- ess materials. These organizations

include the National Center for Resource Recovery, Idaho Mining

Association, Cleveland Cliffs Iron Co., St. Joe Lead Co., American

Cyanamid, Mobil Oil Corporation,

University of Cincinnati, Johns

Hopkins University, Bureau of Mines, U.S. Department of Energy,

U.S. Environmental Protection

Agency, and the Defense

Advanced Research Projects

Agency.

NBS has a number of specialized

facilities at its disposal to help develop the new measurement and

research tools needed to exploit

microorganisms for materials processing. These instruments include

graphite atomic absorption furnaces

for identifying elements in materials,

epifluorescence electron microscopes for studying the structures

of materials as well as the behavior

of organisms, and a small-angle neutron scattering (SANS) facility at the Bureau's research reactor which uses low-energy neutrons as probes to measure the internal structures of materials. These and

several other laboratories for conducting research on materials bio- processing also are available to those in industry and other

organizations for collaborative or independent research. For additional information, call Dr. Frederick Brinckman, A329 Materials

Building, NBS, Gaithersburg, MD

20899, 301/975-5737.

by Roger Rensberger

NBS Public Affairs Specialist

The scientists have established

several collaborative links with industry and other organizations

to carry out their work. Olson

chairs a new task group on microbial ore leaching under ASTM

Committee E-48 on Biotechnology.

This voluntary standards-writing

group is working to develop stan- dard procedures for conducting

bioleaching studies.

In cooperation with the American

Iron and Steel Institute, NBS scientists are investigating the types of organisms that can be used by

industry in two bioprocesses: the

removal of copper from steel scrap

so that the steel can be used for recycling and the removal of insolu- ble phosphorous from domestic

iron ore to make it more desirable

for specialty steel products. Future work may include the development

of reference materials for the quality control of these new bioprocesses.
NEW PUBLICATIONS

HISTORY OF NBS RADIO RESEARCH

Snyder, W.F. and Bragaw. C.L.. Achievement in Radio: Seventy Years of Radio

Science, Technology, Standards, and

Measurement at the National Bureau of

Standards, Natl. Bur. Stand. (U.S.), NBS

Spec. Pub. 555. 842 pages (October

1986). Order by stock no. 003-003-02762-6

from GPO, $55 prepaid.

A massive project to compile the definitive history of radio research at NBS has cul- minated in this publication. Achievement in Radio IS a comprehensive, exhaustive treat- ment of the accomplishments and people

of the Bureau, always set in the context of external events and developments. NBS

was only 10 years old, and practical radio

only about 25, when NBS made its first official radio measurement in 1911, a calibration of a wavemeter. This book tells the

story of NBS' involvement in radio science,

from those spark-and-crystal origins to today's integrated circuits, masers. and

satellites. The authors write from firsthand knowledge of most of the period covered.

NBS STUDY OF 1985 MEXICO CITY

EARTHQUAKE

Stone. W.C., Yokel, F.Y., Celebi, M.. Hanks.

T., and Leyendecker. E.V.. Engineering

Aspects of the September 19, 1985

Mexico Earthquake, Natl. Bur. Stand.

(U.S.). NBS BSS 165, 215 pages (May

1987). Order by stock no. 003-003-02803-7

from GPO, $10 prepaid

Shortly after the September 19, 1985,

earthquake in Mexico City, a research team

from the NBS Center for Building Technology and the U.S. Geological Survey

traveled to the site to provide technical

advice to the rescue effort and to assess

structural damage. This NBS report highlights the findings of the team. The primary cause of the severe structural failure was

unusually strong ground accelerations combined with an exceptionally long duration of shaking. While some areas of Mexico City

suffered devastating structural failures, other areas were only slightly affected. Variations

in subsurface conditions account for the

selective pattern of damage. The researchers compared the response of the struc- tures with Mexican and U.S. design provisions and found that even buildings

specified for the most severe conditions

could have failed in this earthquake. The

implication of this finding is that special provisions should be considered for structures

built over areas that have deep clay

deposits similar to those found in Mexico

City.

INTRODUCTION TO STANDARDS

ACTIVITIES PUBLISHED

Breitenberg, IVI.A.. The ABC's of

Standards-Related Activities in the

United States, Natl. Bur. Stand. (U.S).

NBSIR 87-3576, 23 pages (May 1987).

Order by sending a self-addressed mail- ing label to: Maureen Breitenberg, A629

Administration Building, NBS,

Gaithersburg, MD 20899. telephone

301/975-4031.

This introduction to voluntary standardization, product certification, and laboratory

accreditation programs in the United

States is designed to provide information

for users who may not be familiar with various areas of standardization and the

relationships between groups. Information '

is provided on the history of standardization, types of standards, private standards

groups in the United States, standards

development procedures, and the benefits and problems of standardization such

as participation in the standards process

by qualified consumer representatives.

THE FUTURE OF AUTOMATED

MATERIALS PROCESSING

Bloom, H.M. and Kuchar, N.R.,

editors. A National Forum on The Future

of Automated Materials Processing in U.S. Industry—The Role of Process

Models, Artificial Intelligence and Computer Integration, Natl. Bur. Stand. (U.S.), NBSIR 87-3544, 48 pages (April 1987).

Order by stock no. PB 87-200382 from

NTIS, $1 1 .95 prepaid.

The rapid pace of new technology has

brought a wide variety of new materials into engineered systems. Often their processing

IS far from mature and the materials are

only one step from the research laboratory.

This is one of the many problems facing

process industries that is discussed in this publication. The report is from the second

of two workshops sponsored by the Industrial Research Institute and the White House

Office of Science and Technology Policy,

Committee on Materials, in cooperation with the General Electric Company and NBS. At the May 1986 workshop, experts from

industry, academia, and government

addressed several technologies that can

play an important role in improving the

competitiveness of U.S. process industries through automation. In working sessions,

participants identified state-of-the-art and

technical needs in such areas as process

modeling, artificial intelligence, and computer integration as applied to materials

processing.

GUIDE FOR MAKING ECONOMIC

ENERGY DECISIONS

Ruegg, R.T. and Petersen, S.R., Comprehensive Guide for Least-Cost Energy

Decisions, Natl. Bur Stand. (U.S.), NBS

Spec. Pub. 709, 229 pages (January

1987). Order by stock no. 003-003-02790-1

from GPO, $11 prepaid.

More than a decade after the first shock

from escalating energy prices, millions of buildings in the United States still reflect the

days when oil cost just pennies per gallon.

Many buildings continue to be designed

and constructed with little consideration for energy conservation. The resulting cost to building owners and the nation is enor- mous. A new guide by researchers in the

NBS Center for Applied Mathematics will help builders and building designers, owners, and operators find a balance be- tween energy consumption and energy

conservation which will result in more costeffective building. The publication guides

the decision maker to ask the right

economic questions. It also shows how to structure problems for solution, how to esti- mate future cash flows, and how to inter- pret various measures of economic

performance. Worksheets, a computer pro- gram, and data tables to assist with evaluations are provided in the publication. In addition, a computer program diskette is available from several vendors for under

$20 and will shortly be available from NTIS.

Diskette ordering information is in the publication.

30
REVISED KWIC INDEX OF ENGINEERING STANDARDS

National Center for Standards and

Certification Information Staff, Key-Word-lnContext (KWIC) Index of U.S. Voluntary

Engineering Standards, Natl. Bur. Stand.

(U.S.), 11 microfiche sheets (March 1987).

Order by stock no. PB 87-133377 from

NTIS. $18 prepaid.

NBS has updated its KWIC index for use

by manufacturers, exporters, importers, and

otfiers concerned with standards developed by U.S. trade associations and

technical and professional societies. The

index contains more than 28,000 titles of standards developed by approximately 400

U.S. standards organizations. First published in 1971, the revised microfiche index

provides the title, date, source, and number

of the standard for each entry. Each stan- dard can be found under all significant

keywords in the title. The date of publication or last revision, the standard number,

and an acronym designating the standardsissuing organization appear as a part of each entry.

SEISMIC DESIGN GUIDELINES

Prepared by the Interagency Committee on

Seismic Safety in Construction, Seismic

Design Guidelines for Federal

Buildings, Natl. Bur Stand. (U.S.), NBSIR 87-3524. 102 pages (February

1987). Order by stock no. PB 87- 161204/AS from NTIS. $18.95 prepaid.

NBS, as secretariat of the Interagency

Committee on Seismic Safety in Construction, has issued guidelines for federal agencies to use in designing and constructing buildings to resist earthquake

damage. The report was prepared as part

of the National Earthquake Hazards

Reduction Program. The guidelines are based on existing voluntary standards,

model building codes, and federal regulations. In particular, the technical content is similar to the seismic design requirements on the 1985 Uniform Building Code published by the International Conference of Building Officials. The report includes

information on site planning, structural design criteria, structural analysis proce- dures and design details, as well as

design and construction standards for

structural materials including steel, concrete, and wood. In addition, it includes

nonstructural design requirements, such as

protecting against secondary hazards and

information on quality control and

inspection.

GATT STANDARDS CODE ACTIVITIES

FOR 1986

Overman. J. P., GATT Standards Code

Activities of ttie National Bureau of

Standards 1986, Natl. Bur Stand. (U.S.). NBSIR 87-3538, 32 pages (March 1987).

Order through JoAnne R. Overman. Stan- dards Code and Information, A629

Administration Building. NBS, Gaithersburg,

MD 20899, telephone 301/975-4037.

Manufacturers, exporters, and others

engaged in international trade will be

interested in this annual report which

describes NBS work over the past year as

the official U.S. GATT (General Agreement

on Tariffs and Trade) inquiry point for infor- mation on standards and certification

activities. This includes assisting U.S. industry with trade-related problems, coordinating

comments on proposed foreign regulations

and translations of foreign texts, and

operating the GATT "hotline" that provides

the latest information on foreign notifications from the GATT Secretariat in Geneva,

Switzerland. Highlights of 1986 include

publication of a directory of federal certification programs, background research for

bilateral standards discussion with other

GATT signatories, an update of the KeyWord-ln-Context (KWIC) Index of U.S. Voluntary Engineering Standards, and contributions to the second triennial report to the U.S. Congress on the Standards Code.

1986 LISTING OF NBS PUBLICATIONS

Pardee, R.J., editor Publications of the

National Bureau of Standards— 1986

Catalog, Natl. Bur. Stand. (U.S.). NBS

Spec. Pub. 305. Supplement 18. 389

pages (June 1987). Order by stock no. 003-003-02798-7 from GPO, $18 prepaid.

Scientists and librarians in industry, aca- demia, and government will be interested

in this new catalog which lists approximately 1 ,600 reports and journal articles published by NBS and those appearing

elsewhere during 1986. Papers published

prior to 1986 but not reported previously

also are included. Full bibliographic cita- tions including keywords and abstracts for papers published and entered into the

National Technical Information Service

(NTIS) collection are listed in "NBS Publications Announcements." Entries are arranged by NTIS subject classifications and listed alphanumerically by order

number. Four indexes are included identifying papers by author, keywords, title, and

NTIS order/report number. The catalog also

contains ordering information, availability,

and a list of depository libraries.

COMPLETION OF THE FIRST PHASE

OF U.S. EARTHQUAKE FACILITY

STUDY

Scribner, CF and Culver. C.G., National

Earthquake Engineering Experimental

Facility Study: Phase One—Large Scale

Testing Needs, Natl. Bur. Stand. (U.S.), NBS Spec. Pub. 729. 70 pages (April

1987). Order by stock no. 003-003-

02795-2. $3.50 prepaid.

In 1985, researchers in the NBS Center for Building Technology began a 4-year conceptual engineering design study for a

national earthquake engineering experimental facility. The study was recommended by

the National Research Council to the White

House Office of Science and Technology

Policy. During this past year the NBS

researchers worked with a broad spectrum

of professional engineers, researchers,

industry representatives, building officials, and federal agency representatives to find out their needs for large-scale seismic test- ing. Twenty-three high-priority tests of largescale structures and components were

identified in five areas including low-,

medium-, and high-rise buildings and

industrial processing and power facilities.

ORDERING INFORMATION

To order publications from NTIS, send

request with payment to: National

Technical Information Service, Springfield,

VA 22161. Publications can be ordered

from GPO by mailing order with payment

to: Superintendent of Documents, U.S. Government Printing Office. Washington,

DC 20402.

31
CONFERENCE CALENDAR

Information Resources Management:

Standards for Future Information

Services, NBS, Gaitliersburg, MD

Decembers. 1987

Increased complexity of computer systems,

growing user requirements to transfer data

and processes from one system to another,

and strong international requirements for standards are some of thie forces driving

the standards development process for information technology. As a result of these

forces, standards developers are producing

a complex series of architectural models

and standards that provide a framework for integrating data, voice, and pictures for a

variety of new applications. This conference

will highlight new and emerging standards

that meet user requirements for advanced

integrated systems. Discussions will center on issues related to implementing these

standards as part of the information resources management process. Sponsored by NBS and the General Services

Administration. Contact: Shirley Radack,

B151 Technology Building, NBS,

Gaithersburg, MD 20899. 301/975-2833.

Microstructure and Macromolecular

Research witti Cold Neutrons, NBS,

Gaithersburg, MD

December 8-9, 7987

A major expansion of the neutron scattering

facilities at the NBS 20-megawatt research

reactor is now under way. The Cold Neutron Research Facility (CNRF). scheduled

for completion in 1989, will provide cold neutron beams for many new types of experimental facilities, including several with specialized capabilities for the study of structure and dynamics of materials. The CNRF is intended to be a national

facility serving a broad-based community of researchers in materials science, physics,

chemistry, and biology. In an effort to inform and involve this community at an

early stage while conceptual and detailed

planning for instrumentation for the facility

is progressing, NBS is hosting a series of

workshops, each of which will deal with a major area of cold neutron research.

This workshop will focus on the scientific opportunities in the study of submi- cron structures in materials, including

macromolecular structures in polymers

and biomaterials, which arise from

experimental techniques that take special

advantage of cold neutrons. Technical

talks by invited speakers will review current work in a variety of disciplines and

discuss future extensions utilizing cold

neutrons. Specific instruments and tech- niques related to characterizing submi- cron structures in materials will also be

discussed. An important part of the workshop will be the active participation of the

attendees in assessing the capabilities of, and the need for, various types of instru- mentation for the CNRF. Sponsored by

NBS. Contact: Kathy Stang, A345 Physics

Building, NBS, Gaithersburg, MD 20899,

301/975-4513.

4th International Conference on

Metrology and Properties of Engineering Surfaces, NBS, Gaithersburg, MD

April 13-15. 1988

Metrology and properties of engineering

surfaces have continued to assume great

importance to both the practicing engineer

and the researcher. In recent years, industry has gained increased awareness of the

importance of surface preparation tech- niques. This international conference is the

fourth in a series of meetings, held every 3

years since 1976, on the subject of metrol- ogy and properties of engineering surfaces. The main topics to be discussed at this meeting will be: the application of new sur- face techniques in industry: the development of new tactile instruments; the

development of new techniques for the

optical measurement of engineering sur- faces: the compilation and analysis of data

for specific manufacturing processes; and

the relationships between surface generation and practical performance. Sponsored

by NBS, Coventry Polytechnic, and

Whitestone Business Communications. Contact: Professor K.J. Stout, Coventry

Polytechnic, Department of Manufacturing

Systems, Priory Street, Coventry CV1 5FB,

England, 0203 24166. ext, 278: or Ted

V. Vorburger, All 7 Metrology Building,

NBS, Gaithersburg, MD 20899,

301/975-3493.

Tenth Symposium on Thermophysical

Properties Call for Papers, NBS,

Gaithersburg, MD

June 20-23. 1988

This symposium is concerned with

theoretical, experimental, and applied

aspects of thermophysical properties for gases, liquids, and solids. Appropriate

topics to be included in the symposium

are; thermodynamic properties; transport

properties; optical and thermal radiative properties; interface properties: and data

correlation. Special topics will be: properties

of new materials, properties of gaseous

and liquid mixtures; new developments in experimental techniques; and interpretation

of experimental data in terms of new

theoretical developments.

Prospective authors are requested to submit a 200-300 word abstract before

December 1, 1987. The content of the

abstract will be the basis for acceptance of the paper for presentation at the symposium. If the paper is accepted for presentation, then full papers should be submitted

by June 23, 1988. Sponsored by the

American Society of Mechanical Engineers,

NBS, and The University of Maryland. Contact: Ared Cezairliyan, Room 124 Hazards

Building, NBS, Gaithersburg, MD 20899,

301/975-5931 or J.V. Sengers, Institute for Physical Science and Technology, The

University of Maryland, College Park. MD

20742,301/454-4117.

32
I he National Bureau of Standards was established by an act of Congress on March 3, 1901. The Bureau's overall goal

is to strengthen and advance the nation's science and technology and facilitate their effective application for public benefit.

To this end, the Bureau conducts research and provides: (1) a basis for the nation's physical n-ieasurement system; (2) scientific and technological services for industry and government; (3) a technical basis for equity in trade; and (4) technical

services to promote public safety. The Bureau's technical work is performed by the National Measurement Laboratory, the

National Engineering Laboratory, the Institute for Computer Sciences and Technology, and the Institute for Materials Sci- ence and Engineering.

THE NATIONAL MEASUREMENT

LABORATORY

Provides the national system of physical

and chemical measurement; coordinates

the system with measurement systems of

other nations and furnishes essential ser- vices leading to accurate and uniform

physical and chemical measurement

throughout the nation's scientific community, industry, and commerce; provides

advisory and research services to other

government agencies; conducts physical

and chemical research; develops, pro- duces, and distributes Standard Refer- ence Materials; and provides calibration

services. The laboratory consists of the

following areas:

• Standard Reference Data

• Measurement Services

• Basic Standards

• Radiation Research

• Chemical Physics

• Analytical Chemistry

THE NATIONAL ENGINEERING

LABORATORY

Provides technology and technical ser- vices to the public and'private sectors to address national needs and to solve national problems; conducts research in engineering and applied science in support

of these efforts; builds and maintains

competence in the necessary disciplines

required to carry out this research and

technical service; develops engineering

data and measurement capabilities; pro- vides engineering measurement traceability services; develops test methods

and proposes engineering standards and

code changes; develops and proposes

new engineering practices; and develops

and improves mechanisms to transfer re- sults of its research to the ultimate user. The laboratory consists of the following centers:

• Applied Mathematics

• Electronics and Electrical Engineering

• Manufacturing Engineering

• Building Technology

• Fire Research

• Chemical Engineering

THE INSTITUTE FOR COMPUTER

SCIENCES AND TECHNOLOGY

Conducts research and provides sci- entific and technical services to aid federal agencies in the selection, acquisition, application, and use of computer

technology to improve effectiveness and

economy in government operations in ac- cordance with Public Law 89-306 (40

U.S.C. 759), relevant Executive Orders,

and other directives; carries out this mission by managing the Federal Information Processing Standards Program, developing federal ADP standards

guidelines, and managing federal participation in ADP voluntary standardization activities; provides scientific and

technological advisory services and as- sistance to federal agencies; and pro- vides the technical foundation for

computer-related policies of the federal

government. The institute consists of the

following divisions: • Information Systems Engineering

• Systems and Software Technology

• Computer Security

• System and Network Architecture

• Advance Systems

THE INSTITUTE FOR MATERIALS

SCIENCE AND ENGINEERING

Conducts research and provides measurements, data, standards, reference

materials, quantitative understanding,

and other technical information fundamental to the processing, structure, properties, and performance of materials; addresses the scientific basis for new

advanced materials technologies; plans

research around cross-country scientific themes such as nondestructive evaluation and phase diagram development; oversees Bureau-wide technical pro- grams in nuclear reactor radiation re- search and nondestructive evaluation;

and broadly disseminates generic technical information resulting from its pro- grams. The institute consists of the fol- lowing divisions:

• Nondestructive Evaluation

• Inorganic Materials

• Fracture and Deformation

• Polymers

• Metallurgy

• Reactor Radiation
U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

Gaithersburg, MD 20899

OFFICIAL BUSINESS

Penalty for Private Use, $300

BULK RATE

POSTAGE

& FEES PAID NBS

PERMIT No. G195