GEUM POONG CORPORATION and Sam Young Synthetics Co., Ltd., Plaintiffs-Appellees, and Stein Fibers, Ltd., Appellee, and Samyang Corporation (now known as Huvis Corporation), Appellee, v. UNITED STATES, Defendant-Cross Appellant, v. E.I. DuPont de Nemours, Inc., Arteva Specialities S.a.r.l. (doing business as KoSa), and Wellman Inc., Defendants-Appellants