Hydrogenic model and Hartree-Slater model give good results for evaluating the K-shell excitation cross-section. A comparison of K-edge and cross-section profiles for low atomic number (Z) elements  shows that the cross-section profiles present the K-edge roughly for an edge where the fine structures are important, e.g. for boron nitride (BN).
Figure 3414a (a) shows a HAADF-STEM image of single-layered h-BN (hexagonal boron-nitride) and Figure 3414a (b) is a corresponding atomic model where a EELS linescan has been recorded, shown in (c) and (d). The STEM contrast of the N and B locations is determined by the atomic number, called Z-contrast. Figure 3414a (c) and (d) shows the EELS profiles of the boron K-edge and nitrogen K-edge signals, respectively. The N K-edge intensity does not go down to zero even between two nitrogen atoms because of EELS signal delocalization . The large probe tail and mechanical instabilities such as the specimen drift during the line scan may also partially contribute to the nonzero intensity but this should not be a dominant effect because the simultaneously recorded STEM profile clearly shows well-separated atoms similar to the STEM signal presented in Figure 3414a (a).
Figure 3414a. (a) A HAADF-STEM image of single-layered h-BN (hexagonal boron-nitride), (b) A corresponding atomic model where an EELS linescan was recorded (red: nitrogen, blue: boron), and (c) and (d) the EELS profiles of the boron K-edge and nitrogen K-edge signals. Adapted from 
Figure 3414b shows a boron monovacancy [4, 5] (indicated by the darkest contrast in (a)), in single-layered h-BN (hexagonal boron-nitride), induced by the knock-on effect.
Figure 3414b. (a) A boron monovacancy shown by the darkest contrast in the HAADF-STEM image of single-layered h-BN and (b) A corresponding atomic model (red: nitrogen, blue: boron). Adapted from 
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