Correction Appended

At the Xerox Corporation's research center here is a remarkable model, a miniature structure covered with a wired web of sensors that look like small baby-bottle nipples. Working together, sensors like these may someday enable buildings or highway overpasses to adjust instantly so that they dance in harmony with an earthquake, rather than crumble under its tectonic force.

This is cutting-edge research to be sure -- and highly pragmatic here, three miles from the San Andreas Fault. But nimble buildings are just one possibility that researchers envision for a little-known but promising technology called micro-electro-mechanical systems.

These Lilliputian sensors, motors, nozzles, valves or other mechanical systems will be able to sense heat, light, motion and sound. Placed on the surface of computer chips, these tiny devices will also be smart enough to interpret what it all means and take action.

Some of the more intriguing applications now in the lab include an airplane wing that can maneuver without the aid of either ailerons or rudders. Instead, the skin of the wing has a ''peach fuzz'' of two-tenth-millimeter sensors. Controlled by computers, these minuscule flaps can monitor the air sweeping across a wing in flight and respond in concert to stabilize or even turn an aircraft.

Other futuristic applications include substitutes for paint that fill in cracks or release a fire retardant when exposed to heat; automobile bumpers that repair themselves, and sensors embedded in a cellular telephone that could pinpoint the user's location.

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Increasingly sophisticated micro-electro-mechanical systems, known as MEMS, may soon be making their way into so many elements of everyday life that many scientists and engineers believe they could eventually have an effect as profound as that of the microchip.

''The 1980's were defined by the microprocessor, and cheap lasers have made possible the communications advances of the 1990's,'' said Paul Saffo, a computer industry consultant at the Institute for the Future in Menlo Park, Calif. ''The first decade of the next century is going to be shaped by MEMS.''

Micro-electro-mechanical systems are already much more than a futuristic vision. An estimated $2.2 billion worth of these devices are sold annually for use in products like automobile air bags and home blood-pressure kits. And a market is seen emerging for inexpensive chemical analysis instruments -- the equivalent of a laboratory on a chip.

Especially in the aftermath of disclosures that troops during the Persian Gulf war were exposed to toxic residue from destroyed Iraqi munitions dumps, the Pentagon is eager to have inexpensive, portable means for detecting chemical and biological weapons. With MEMS, researchers hope to replace cumbersome $17,000 laboratory spectrometers -- instruments that measure light waves to determine the chemical composition of substances -- with $20 devices that could easily be carried by foot soldiers.

Typically, the goal with MEMS is either to replace existing devices with cheaper, more efficient technology, or to develop entirely new capabilities that were once simply beyond the reach of earlier electro-mechanical technologies.

In less than a year on the market, for example, a $7 MEMS sensor from a company called Analog Devices has become the leading motion detector used in automobile air bags. The sensor, which instructs the air bag to inflate, consists primarily of a microscopic whisker of silicon that can detect a car's sudden deceleration when it hits an object. The Analog Devices sensor is not only less than half the price of earlier mechanical sensors, but industry engineers say it is much more reliable.

And a new type of projection-television system, with much brighter, sharper pictures than previously available, has a MEMS-based video-display system developed by Texas Instruments. The projector is powered by an array of millions of microscopic controllable mirrors floating on a single silicon chip called a digital light processor. Projection systems that are based on the technology, used primarily for business conferences in auditoriums and other large-audience settings, are now being sold by manufacturers, including Electrohome, In Focus Systems, Nview and Proxima.

Despite the recent rush toward MEMS in laboratories in the United States, Asia and Europe, the underlying ideas were conceived nearly four decades ago.

One early proponent of micro-miniaturization was Richard Feynman, a professor at the California Institute of Technology who would later win a Nobel Prize for his work in quantum physics. In a now-famous 1959 lecture at the annual meeting of the American Physical Society, Dr. Feynman urged engineers to pursue ultra-small technology for manipulating and controlling things and processes, speculating that tiny computers would one day be able to store the contents of the Encyclopaedia Britannica on the head of a pin. (An angels' dance that is now within the realm of the feasible.)

Today, dozens of small American start-up companies are on the brink of bringing new MEMS applications to market. In Silicon Valley, for example, a company called Cepheid is developing micro-instruments for biomedical testing, including a fluid-testing chip that will combine valves, sensors and channels all on a single sliver of silicon. Intended to test blood and urine for a variety of medical conditions with high accuracy at low cost, the device is expected to reach the market within a year.

Another company, Redwood Microsystems, is building pressure-flow regulators and micro-valves that make laparoscopic surgery and other medical and industrial applications more precise and less expensive. Silicon Light Machines is working on an alternative approach to Texas Instruments' digital light processor, using tiny gratings that act as electronic prisms to diffract light, rather than reflect it, producing full-color images from a single beam. And a start-up called Telenekron is working on a new class of chemical sensors for various uses in gas meters and automobiles.

One reason MEMS researchers are so confident about progress is that the technology draws on many of the powerful manufacturing techniques already well proved by the semiconductor industry -- techniques that can churn out millions of copies of even the most complex designs at remarkably low cost.

In creating a microscopic MEMS pressure sensor, for example, engineers employ the same kinds of masks and etching compounds used in the production of silicon chips. By etching away most of the surface material they are able to create a diaphanous diaphragm as thin as a single micron. (A human hair is at least 75 microns thick.) Pressure from these sensitive diaphragms can be read by a thin layer of electrical resistors embedded into the surface, whose voltage fluctuates with the diaphragm's subtlest movement.

To be sure, big challenges remain for MEMS researchers. Placing millions of individual components on a tiny microchip is only the beginning. Making these arrays work in concert is a matter taxing even the expertise of researchers adept at a field known as massively parallel computing.

MEMS developers, led by Andrew Berlin, a scientist at Xerox's Palo Alto Research Center, face just such a task in trying to figure out how those future highway-support columns would coordinate the small electronic pulses from the millions of MEMS sensors coating the column's surface. The pulses would be used to damp the vibrations from an earthquake, but no known computer would be fast enough to control such a multitude of sensors.

By programming the individual sensors to interact only with their neighbors, however, it may be possible to break down the computing problem to a manageable size. Already, the Xerox team has used this approach in the laboratory to increase more than fivefold the strength of a model column for brief periods.

Whatever the technical obstacles, the new frontier of MEMS could also bring with it thorny social problems. For example, a 1995 study group in the United States, sponsored by the Advanced Research Projects Agency of the Pentagon, proposed the idea of ''surveillance dust.'' Each dust particle would consist of tiny sensors with a miniature parachute, microphone and infrared detector. Sprinkled over a battlefield, this dust would float for five hours or more to give pinpoint information on enemy locations. Privacy experts, however, worry that such technology could soon be widely deployed for civilian as well as military applications.

But such concerns seem unlikely to slow the MEMS forward thrust. Despite some still-formidable technology hurdles, industry pioneers are now confident that they will be able to replicate the prodigious feats of the microelectronic world -- in the new micro-mechanical realm.

The optimists include Gordon Moore, chairman emeritus of the chip maker Intel, who helped turn the transistors of the 1950's and 1960's into the semiconductor chips of the 70's, 80's and 90's.

''It took a long time for the transistor to have an impact,'' he noted. ''MEMS is a really intriguing technology, and I believe it will have a significant impact in the next century.''

Correction: February 3, 1997, Monday An article in Business Day last Monday about advances in the field of quantum computing misstated the nature of a discovery announced by scientists at the City College of New York, the University of Barcelona and the Xerox Corporation. The scientists discovered that a magnetic material under study exhibited the properties necessary for quantum computing. They did not discover the material itself, which was first synthesized in 1980.

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