Historical clue formulations

• Lead-in to amorous — 2020-07-31
• Synthetic fiber, for short — 2019-07-05
• Cal ___ — 2018-04-08
• Part of many a tech school's name — 2012-04-27
• Cal ___ — 2009-12-19
• With 19-Across, domain of civics, in brief — 2008-05-16
• Roly-___ — 2007-04-23
• Prefix with graph — 2004-03-21
• Cal ___ — 2000-04-14
• Prefix with ethnic — 2000-01-22