Bi2O2CO3/ZnWO4 composite photocatalysts have been successfully synthesized by a mixed calcination method after hydrothermal process. The catalysts were characterized by powder x-ray diffraction, scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, x-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectrum. The results showed that the hierarchical Bi2O2CO3/ZnWO4 nanocomposites were obtained by mixed grinding calcination method and Bi2O2CO3 nanospheres grow on the primary ZnWO4 particles. The Bi2O2CO3/ZnWO4 composites exhibit higher photocatalytic activities compared to pure ZnWO4 and Bi2O2CO3 particles under UV light irradiation. Furthermore, the excellent photocatalytic efficiency of the Bi2O2CO3/ZnWO4 composite was deduced closely related to Bi2O2CO3/ZnWO4 heterojunctions whose presence is generally regarded to be a favorable factor for the separation of photogenerated electrons and holes.

To provide insight into the influence of the length scale on the kinetics of phase evolution during severe plastic deformation, we studied the microstructure evolution of cryomilled Al and Ti mixture, which is further subjected to high-pressure torsion (HPT). The cryomilled microstructure consisted of elemental Al and Ti, and the subsequent HPT deformation at ambient temperature led to the solid state formation of Al-rich intermetallics. X-ray diffraction peaks originating from TiAl2 and TiAl3 were observed after one revolution of HPT, suggesting a shear strain-assisted formation of the intermetallics. A high resolution transmission electron microscope confirmed the formation of TiAl2 following HPT for one revolution. Further HPT straining led to microstructure refinement and a mixing of the Ti and Al, as well as of any phases formed initially. The solid state formation of the intermetallics and the overall evolution of the microstructure are discussed based on the generation of a high density of lattice defects that evolve under the strain conditions present during HPT.

CuInS2 (CIS) quantum dots (QDs) with different diameters were prepared and their optical properties were studied. The optical band gap of QDs, as estimated by absorption spectrum, was found to decrease with increase in size. The stokes shift between absorption and photoluminescence peaks was observed to be larger (>100 meV) in all the three samples. This shows that the defect states available in the forbidden gap dominates the recombination mechanism. The variation in the emission peak with QD size, however, indicates that the relaxation dynamics in CIS QDs involves both excitonic level as well as the defect states.

A large depth of 800 μm gradient microstructure was produced in pure titanium (Ti) by means of surface rolling treatment (SRT). The microstructural characteristics with different depths from the top surface were analyzed by optical microscopy, transmission electron microscopy, and electron backscattered diffraction. The results showed that, on the outmost surface, nanograins with an average grain size of ∼100 nm were achieved. In the subsurface, i.e., the deformation twinning region, a large volume fraction of {10 $\overline 1$ 2} deformation twins together with a low fraction of {11 $\overline 2$ 2} and {11 $\overline 2$ 4} twins were identified. Based on the microstructural analysis, the grain refinement mechanisms with increasing strain are summarized as: (i) prior division by deformation twinning, (ii) refinement effect of subgrain boundaries resulting from the accumulation of high density of dislocation, and (iii) transformation effect from low angle grain boundaries to high angle grain boundaries. The results of tension tests also show that the titanium sample after SRT shows higher strength than the as-received titanium sample.

To obtain a nanocrystalline surface layer, 316L stainless steel was treated by fast multiple rotation rolling (FMRR). The microstructure, after FMRR treatment and annealing treatment, was characterized by transmission electron microscopy and x-ray diffraction. Equiaxed nanocrystalline with the average grain size about 12 nm is obtained on the surface layer of FMRR sample. The investigation of thermal stability of the nanocrystalline layer indicates that the grains are still nanocrystalline and the average grain size is about 60 nm for annealing at 500 °C. In addition, the amount of α-martensite increases markedly as the annealing temperature increases from 300 to 500 °C. However, it begins to reduce at 600 °C due to the reversion transformation from martensite to austenite. After annealing at 400 °C, the microhardness of the annealed FMRR sample reaches a maximum value of about 660 HV, and it is four times higher than that of the original sample.

Graphene's layered structure has opened new prospects for the exploration of properties of other monolayer-thick two-dimensional (2D) layered crystals. The emergence of these inorganic 2D atomic crystals beyond graphene promises a diverse spectrum of properties. For example, hexagonal-boron nitride (h-BN), a layered material closest in structure to graphene is an insulator, while niobium selenide (NbSe2), a transition metal dichalcogenide, is metallic, and monolayers of other transition metal dichalcogenides such as molybdenum disulfide (MoS2) and tungsten disulfide (WS2) are direct band gap semiconductors. The rich spectrum of properties exhibited by these 2D layered material systems can potentially be engineered on-demand and creates exciting prospects for using such systems in device applications ranging from electronics, photonics, energy harvesting, flexible electronics, transparent electrodes, and sensing. A review of the structure, properties, and the emerging device applications of these materials is presented in this paper. While the layered structure of these materials makes them amenable to mechanical exfoliation for quickly unveiling their novel properties and for fabricating proof-of-concept devices, an overview of the synthesis routes that can potentially enable scalable avenues for forming these 2D atomic crystals is also discussed.