A federal jury convicted a retired University of Tennessee professor Wednesday of passing sensitive information from a U.S. Air Force contract to two foreign research assistants from China and Iran.

Jurors deliberated about six hours before finding plasma physics expert J. Reece Roth guilty Wednesday on 18 counts of conspiracy, fraud and violating the Arms Export Control Act.

Prosecutors in the Knoxville trial said Roth gave the two graduate students access to sensitive information while they researched a plasma-guidance system for unmanned aircraft.

Roth, 70, testified last week that he didn't break the law.

He faces up to 160 years in prison and more than $1.5 million in fines. Sentencing is scheduled for Jan. 7.

Prosecutors presented several documents suggesting research by Roth's university laboratory or a spinoff company, Atmospheric Glow Technologies Inc., was restricted.

But Roth insisted that he didn't break the law because he hadn't proved that his research worked.

"My understanding was that it only applied to things that worked, and we had not shown that. We had a lot of work to do," Roth testified.

Roth is also accused of taking reports and related studies in his laptop to China during a lecture tour in 2006, and having one report e-mailed to him there through a Chinese professor's Internet connection.

The government seized materials from Roth's office and took his computer from him at the airport when he returned from the trip. Prosecutors claim he violated the export control act simply by taking the laptop with sensitive materials outside the country even if, as forensic evidence showed, he didn't open all of those files while he was in China.

The charges involve work performed from 2004 to 2006 on two Air Force contracts by Roth, graduates students Xin Dai of China and Sirous Nourgostar of Iran, and university spinoff company Atmospheric Glow Technologies Inc. of Knoxville.

Atmospheric Glow Technologies recently pleaded guilty to 10 counts of exporting defense-related materials and Roth protege Daniel Sherman has pleaded guilty to related charges. Sentencing in those cases in still pending.