e} \sim 0.483$) in the lower density region. Since $Y_{\rm e} > 0.46$, $^{50}$Ti ($Y_{\rm e} \sim 0.440$), $^{54}$Cr ($Y_{\rm e} \sim 0.444$) and $^{58}$Fe ($Y_{\rm e} \sim 0.448$) are not produced abundantly in the present models. The behavior in $Y_{\rm e}$ and the resulting electron capture reactions are largely consistent with the 2D deflagration model presented in Travaglio et al. (2004a). The electron captures, however, are less efficient in the 2D models than in the 3D deflagration model (Travaglio et al. 2004a) and in the classical 1D models (Thielemann et al. 2004; see also §3.6). This is likely due to the weaker deflagration in the present models than in the others (1D and 3D), although an uncertainty is involved in the treatment of the temperature evolution in the NSE regime (§2.2).

Figure 10 shows the comparison between $Y_{\rm e}$ before and after the DDT. In the C-DDT model, $Y_{\rm e}$ is not affected by the detonation wave as is consistent with previous 1D models. On the other hand, in the O-DDT model the detonation slightly affects $Y_{\rm e}$ especially of the material which was hardly processed by the deflagration ($\sim Y_{\rm e} \gsim 0.496$). The change in $Y_{\rm e}$ 