Ned Barnholt, president and CEO of Agilent Technologies Inc., has been named chairman of the company's board of directors. Barnholt replaces Gerald Grinstein, who will retire from the board in March 2003. Grinstein, 70, will remain lead director through February. Upon Grinstein's retirement, board member David Lawrence will become lead director.   . . .   G. Kirk Raab was elected chairman of the board at Applied Imaging Corp., succeeding Jack Goldstein, Ph.D., who will continue as a director.