* William Kuehn has resigned as chairman...

* William Kuehn has resigned as chairman and chief executive of SFE Technologies, an ailing San Fernando-based electronics concern that hired Kuehn as a “crisis manager” 18 months ago. Kuehn, noting that he directed SFE’s sale of some troubled subsidiaries and other restructuring steps, said that the company now “does not really need my full-time services” and that he had worked at SFE only part-time in recent months. Richard Green, an SFE director, was elected to succeed Kuehn as chairman of the board, but most of Kuehn’s operating duties will be assumed by Michael Rosenberg, SFE’s president, and Jerome J. Jahn, executive vice president, the company said.