Fig. 6. (a)–(d) Structural characteristics of strong active materials in the negative cross-sectional images , where y_N1 = 7.14 mm and κ = 1, 2, 3, 4. (c)–(h) Structural characteristics of strong active materials in the positive cross-sectional images , where y_P1 = 0.82 mm and κ = 1, 2, 3, 4. (i) Effect of working condition on the number of pixels of strong active materials in . (j) Effect of working condition on the number of pixels of strong active materials in .