Figure 1. Nano-silica-fused whisker, fracture toughness, and a notch. In (A), the nano-silica particles (S) are indicated by the arrow, and ‘W’ designates the whisker. In (B), each value is the mean of 6 measurements, with the error bar showing 1 standard deviation (SD) (mean ± SD; n = 6). Dissimilar letters indicate values that are significantly different (Tukey’s multiple-comparison test; family confidence coefficient = 0.95). In (C), optical micrograph shows an example of a notch in unfilled resin showing the sharpness of the notch tip produced by the single-edge-V-notched beam method.