(19)

(11)

EP 1 073 916 A1

(12)

(43) Date of publication: 07.02.2001 Bulletin 2001/06 (21) Application number: 99918794.1 (22) Date of filing: 22.04.1999

(51) International Patent Classification (IPC)7: G01V 3/32, G01R 33/44 (86) International application number: PCT/US9908/862 (87) International publication number: WO 9954/759 (28.10.1999 Gazette 1999/43)

(84) Designated Contracting States: AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 22.04.1998 US 82647 P (71) Applicants: SOUTHWEST RESEARCH INSTITUTE San Antonio, TX 78238-5100 (US) King, James Derwin San Antonio, TX 78255 (US) Qingwen, Ni San Antonio, TX 78249 (US) De Los Santos, Armando San Antonio, TX 78229 (US)	(72) Inventors: KING, James, Derwin San Antonio, TX 78255 (US) QINGWEN, Ni San Antonio, TX 78249 (US) DE LOS SANTOS, Armando San Antonio, TX 78229 (US) (74) Representative: Lawrence, John  Barker Brettell 138 Hagley RoadEdgbaston Birmingham B16 9PW Birmingham B16 9PW (GB)