A.20-30Ω.mB.20-60Ω.mC.20-50Ω.mD.10-50Ω.m
A.1處,90%B.2處,85%C.3處,80%D.4處,75%
A.厚度不應(yīng)小于100mmB.厚度不應(yīng)大于100mmC.厚度不應(yīng)小于200mmD.厚度不應(yīng)大于200mm