Justin Dix of Cornell, Amanda Smith of Luther and Joel Cornilsen of Loras were named Athletes of the Week in the Iowa Conference on Monday.    Dix, a senior from Mount Vernon, went 6-0 last week in wrestling with five pins. He won the championship at 174 pounds Saturday at the Central Invitational by pinning all four of his opponents: Andy LaMere of Wisconsin-River Falls in 2 minutes, 21 seconds, Joe Moon of Augsburg in 3:56, Nathan James of Lindenwood in 5:55 and John Venne of Lindenwood in 37 seconds. James is ranked second in the nation in the NAIA. Earlier in the week, Dix pinned Tom Atkinson of Central in 2:17 and beat Donnie Davis of William Penn 13-8 in dual-meet action. Dix, who placed third in the Iowa Conference and was an NCAA Division III national qualifier last season, is 13-1 this year with 11 falls.    Smith is a junior guard from Decorah, led Luther to a pair of victories in three games last week.     Cornilsen, a sophomore forward from Clinton, helped Loras win two of three basketball games last week.    A three-member committee of sports information directors from Iowa Conference colleges selects the Athletes of the Week based on nominations open to any sports information director in the conference.