Dr. Sivana is one of Buck Rogers' friends in his comic strip adventures. That's him on the left, Buck Rogers in the middle, and Wilma Deering on the right.
Dr. Huer says "Heh!" a lot.
Dr. Sivana is another scientist. He's a bad guy in Captain Marvel comic books. That's him on the left, and Captain Marvel is on the right.
Dr. Sivana also says "Heh!" a lot, but nobody ever seems to notice the resemblance to Dr. Huer, possibly because they're too busy congratulating Captain Marvel on his prowess with firearms.
You also see similar mad scientists in other comics. This one is a bad guy in SUB-MARINER #35. He looks a great deal like Dr. Sivana, although he doesn't say "Heh!" for some reason.