專用

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.

用 = 丨 + 月 : Mnemonic symbol: a first aid kit. Can you see the cross on the container?

用 = 丨 + 月 : Yu the Great hurt her leg when she slipped in the engine's bathroom. The moon helps her to splint her leg using the bathroom's first aid kit and a dinosaur bone.