1 Subjects: “...energy efficiency index...”

2 Subjects: “...energy efficiency improvement...”

3 Subjects: “...energy efficiency...”

4 Subjects: “...power conversion efficiency (PCE)...”

5 Subjects: “...energy efficiency...”

6 Subjects: “...environmental efficiency...”

7 Subjects: “...high energy efficiency...”

8 Subjects: “...urban land use efficiency...”

9 Subjects: “...water-use efficiency...”

10 Subjects: “...resource use efficiency...”

11 Subjects: “...efficient operation...”

12 Subjects: “...surface efficiency of the process...”

13 Subjects: “...efficiency...”

14 Subjects: “...efficiency...”

15 Subjects: “...energy efficiency...”

16 Subjects: “...energy efficiency...”

17 Subjects: “...entrapment efficiency...”

18 Subjects: “...entrapment efficiency...”

19 Subjects: “...tsunami efficiency...”