Fig. 1

Soft TXM nCT taken at 510 eV incident X-ray. Typical TXM image is shown in (a), with a 3 μm scale bar. A reconstructed tomogram of a particle ~5 μm width is shown in (b), with a 1 μm scale bar. A 3-D reconstruction of a 1.5 × 1.5 × 5 μm section (and shown in dotted line in (b)) is shown in (c). Its negative imprint, or the voids, is shown in (d).