Cryo soft X-ray tomography (Cryo-SXT) is a valuable tool for high-resolution three dimensional (3D) imaging of cells in near-native preservation state. Cryo-immobilization of cells based on rapid cryogenic freezing is crucial to obtain good imaging in Cryo-SXT. In order to acquire high contrast image of live cells, it need to prepare the specimen ice as thin as possible. However, as the thickness of the ice layer is further reduced, the live cells may be destroyed during the tilt series data collection of 3D imaging due to radiation. Thus, it is essential to seek out a proper thickness range of the ice layer to get high contrast image without radiation damage of cells. For further understanding the relationship between thickness of ice layer and degree of radiation damage, yeast cells with different thickness of ice layer were imaged using Cryo-SXT. Finally the ice layer with thickness about 10 μm was confirmed to be proper for good imaging.
Composites of La0.4Sr0.6Co0.8Fe0.2O3−d (LSCF) with samarium doped ceria (SDC) have been extensively used as cathodes
for solid oxide fuel cells (SOFCs) to lower its operation temperature. The ability to visualize three-dimensional (3D)
microstructural changes in LSCF-SDC composite cathodes can help elucidate the impact of microstructure on cathode
performance. This study reports that we utilize the nano-computed tomography (nano-CT) technique to image the 3D
microstructures of La0.4Sr0.6Co0.2Fe0.8O3 (LSCF) - Ce0.8Sm0.2O1.9 (SDC) composite cathodes which were sintering at 800,
1000, and 1200°C, respectively, for 2 h based on the Fe K-absorption edge. Using the reconstructions of LSFC-SDC
composite cathodes submitted to different temperatures, the key microstructural properties, such as volume fraction of
each phase, connected volume fraction, surface area, triple-phase boundary length, and pore size were measured. The
effect of sintering temperature on the microstructure of LSFC-SDC cathodes was discussed and compared with
theoretical simulation. With increasing sintering temperature in the range from 800 to 1200°C LSFC-SDC composite
cathode microstructure was found that the volume fraction and grain size of LSCF material increased, while the volume
fraction of SDC decreased. Furthermore, the triple-phase boundary length per volume increased as the sintering
temperature increasing. This study had revealed that the nano-CT can provide a powerful tool to investigate the 3D
microstructure of energy materials and optimize its preparation condition to gain better functional performance.
Nano-CT has been considered as an important technique applied in analyzing inter-structures of nanomaterials and
biological cell. However, maximum rotation angle of the sample stage is limited by sample space; meanwhile, the scan
time is exorbitantly large to get enough projections in some cases. Therefore, it is difficult to acquire nano-CT images
with high quality by using conventional Fourier reconstruction methods based on limited-angle or few-view projections.
In this paper, we utilized the total variation (TV) iterative reconstruction to carry out numerical image and nano-CT
image reconstruction with limited-angle and few-view data. The results indicated that better quality images had been