Institution: University At Buffalo
Contact: Ellen Goldbaum , Public Information Officer
E-mail: goldbaum@newsb.buffalo.edu, Phone: 716-645-2626
Posted7/17/98
UB Professor Looking To Identify Mechanism Behind Observation Of Negative
Electrical Resistance
BUFFALO, N.Y. -- A University at Buffalo professor who last week reported
at a scientific meeting that she had observed apparent negative electrical
resistance at the interfaces between layers of carbon fibers in a composite
material is conducting additional studies to clarify the mechanism behind
the phenomenon.
Deborah D. L. Chung, Ph.D., professor of mechanical and aerospace
engineering at UB, said that while she also observed the conduction of
electricity with zero resistance when the composite was combined with
another carbon composite that is a conventional, positive resistor -- an
indication of superconduction -- her findings do not indicate that the
combination is itself a superconductor.
Chung, who holds the Niagara Mohawk Chair in Materials Research at UB and
is recognized internationally for her work in smart materials and carbon
composites, presented the results on July 9 in a keynote address at the
fifth International Conference on Composites Engineering in Las Vegas.
She said that she and Shoukai Wang, a doctoral candidate in UB's Department
of Mechanical and Aerospace Engineering, observed continuous negative
electrical resistance in a carbon-fiber composite in a direction
perpendicular to the fiber layers.
According to Chung, negative resistance indicates that the electrons in the
system are flowing in a direction opposite to that in which they normally
flow.
She stressed that the mechanism behind the observation of negative
resistance at the geometrically complex interface between fiber layers is
still unclear.
Chung said that she is working to identify an energy source responsible for
the negative-resistance phenomenon.
She and Wang made the observations while evaluating how different curing
pressures and matrix materials affected the junction between carbon-fiber
layers.
Chung said that they looked at their initial results skeptically, doubting
at first that what they were seeing was correct. After checking and
rechecking the connections, and after using different meters over a period
of time, they concluded that it was truly negative resistance that they
were seeing.
Chung and Wang are continuing to study the phenomenon.
Chung's presentation at last week's conference included a demonstration of
the negative-resistance phenomenon, in which a carbon fiber-cement-matrix
composite was hooked up to a voltmeter that indicated negative electrical
resistance.
A paper describing the research has been submitted to a peer-review journal.
A patent application has been filed.
Editor's Note: An earlier news release entitled "SUPERCONDUCTION AT ROOM
TEMPERATURE: NEGATIVE ELECTRICAL RESISTANCE SEEN IN CARBON COMPOSITES" was
issued on July 9, 1998, by the University of Buffalo news office but was
later pulled off their Web site. In that release, the claim was made that
"Materials engineers at the University at Buffalo have made two discoveries
that have enabled carbon-fiber materials to superconduct at room
temperature." A spokesperson earlier this week said that the news release
was pulled "because we are at the moment trying to get some answers to some
fairly important questions ... that have been asked already." The news
office subsequently issued a revised news release, which we have reposted
here.
The complete news release is available at
http://www.buffalo.edu/news/Latest/ChungResistance.html