Patterned hydrogel films are attractive for the generation of 3D multicellular spheroids, a new in vitro cell model. Traditional methods for their synthesis, such as photolithography and micromolding, usually require a template and are difficult to fit into commercial cell culture plates. Here a simple method to synthesize patterned poly(2-hydroxyethyl methacrylate) (PHEMA) films were developed. First PHEMA films were synthesized in situ in the wells of cell culture plates by bulk redox polymerization of the monomer. Films with a corrugated surface were usually obtained. Fortunately a narrow range of initiator concentration was identified in which smooth films could be obtained. Then water was added to swell the films and wrinkling patterns were produced spontaneously. The shape and size of the patterns can be controlled by adjusting cross-link density and film thickness. Under optimized conditions, films with regular hexagonal patterns were obtained successfully. The patterned PHEMA films were further used to generate multicellular spheroids. The resulting spheroids exhibit high viability and narrow size distribution.

The corrosion behavior of Zr alloys was affected by second phases, especially by those containing Fe and Nb. Ti 2 Ni-type (Zr,Nb) 2 Fe compound was melted and exposed to H 2 O 2 water solution at 320 °C and 16.4 MPa for 60 hours. The oxide layer was analyzed by X-ray diffraction and high-resolution transmission electron microscope (HRTEM). The formation of nano-crystalline tetragonal ZrO 2 (Fe-rich area) and amorphous ZrO 2 (Fe-deficient area) was observed. HRTEM analysis identified α-Fe could stabilize tetragonal ZrO 2 due to the epitaxial growth.ZrxFeyNb alloys with different iron were melted and corroded similarly. The result was consistent with the proposed mechanism.

Transmission electron microscopy and energy dispersive X-ray spectroscopy have been used for crystallographic and compositional characterization of nano-precipitates distributed within the α-Zr matrix of the ZIRLO alloy. Intermetallic nano-particles with the C14 Laves-phase structure were found to be the dominant precipitate phase typically larger than 60 nm in sizes, which is assigned to the Zr(Fe,Nb)2 formula with Fe and Nb being mixed on the second sublattice sites in the bracket. Stacking faults were also observed in the ternary Laves phase, together with dislocations presenting on prism planes of the matrix solid solution. Besides, some fine spherical β-Nb particles about 30 nm in size were also found to precipitate within the α-Zr grains, with the α/β interface being crystallographically coherent.

The fabrication of high-performance, low-cost photocatalysis materials, which absorb in the visible-light region, is of significance for their practical applications. A Ti 2 O@TiO 2 (rutile) core-shell structure was fabricated through dehydrogenation and oxidation from TiH 2 . Thermal analysis indicates that a bimodal oxidation behavior accounts for the formation of a bi-phasic composite. The response of the composite under UV and visible light was measured by PL (photoluminescence) spectra and a photo-degradation test. A pronounced improvement in photo-degradation performance is attributed to the synergistic function of exciton separation of the core-shell structure and the visible light response of the Ti 2 O cores.

The crystallographic characterization and defect structure of precipitates plays a key role in the properties of Zr alloys. The precipitates in Zircaloy-4 alloy are studied in this work. The Zr-Fe-Cr particles are identified as the dominant precipitates at room temperature with C14 or C15 type Laves structure. The Fe/Cr ratio of C15 type Zr-Fe-Cr phase is slightly lower than that of C14 type phase. The {0001} stacking faults in C14 phase is observed and analyzed for the first time. Some new orientation relationships of C14 and C15 phases with α-Zr are identified.