解:?$(1)$?由題意可得?$2^2 \oplus 2^3=2^{2×3}+2^{2+3}=2^6+2^5=64+32=96$?
?$(2)2^p \oplus 2^q=2^{p×q}+2^{p+q}$?
∵?$2^p=3,$??$2^q=5,$??$3^q=7$?
∴?$2^{p×q}=(2^p)^q=3^q=7,$??$2^{p+q}=2^p×2^q=3×5=15$?
∴?$2^p \oplus 2^q=7+15=22$?
?$(3)3 \oplus 3^t=3^{1×t}+3^{1+t}=3^t+3×3^t=4×3^t$?
∴?$4×3^t=108$?
?$3^t=27=3^3$?
∴?$t=3$?