sentence2_structure: You<>call<>materials able to conduct electricity with 100% efficiency
sentence1: We are also studying highly efficient energy conversion mechanism, electrical energy transmission and storage, superconductor and its application, power electronics and control of electrical machines, and aspects of energy problems.
sentence2: You call materials able to conduct electricity with 100% efficiency, meaning that no energy is lost during the electrical transmission, superconductors.
question: What do you call materials able to conduct electricity with 100% efficiency, meaning that no energy is lost during the electrical transmission?