中专

中 = 丨 + 口 : Mnemonic symbol: a dart board, because you always try to hit the center.

Julian Giant Squid (zhu-) is throwing dinosaur bones (丨) as darts on a dart board in front of the engine ((e)ng1). To make it a bit more difficult he's throwing mandarins (口) into the air as well and skewers them up right in the center (中 is a mandarin skewered on a dinosaur bone) in mid flight with the dinosaur bones. He's still able to consistently hit the center (中) of the dart board.

专 = 二 + ㇉ + ㇏ : Let's say the expert is a scientist. Also, 专 reminds me a little bit of the wheelchair symbol. Thus I choose a scientist in a wheelchair as symbol for 专.

专 = 二 + ㇉ + ㇏ : In front of the anthill, the scientist and Julian Giant Squid are focused on one thing: Electrifying the wheelchair of the scientist. Deeply concentrated they connect a capacitor to the wheelchair, which indeed starts to move a little.