Taken from enter link description here
Quantum Capacitance Overcharge it anyway.
Remote Detonation Kill a Barnacle with a Satchel.
Unified Coupling Theorum Help the Barnacle and Headcrab find true love. [0/10]
Permeable Infrastructure Use the alternative path in the Office Complex.
I'm having trouble with these four in Black Mesa: Source. I have already completed all the other achievements, but these have stumped me.
What exactly is a Barnacle? Do they mean Headcrabs? I'm very confused.