The electrophysical and structural properties of InAlAs/InGaAs/InAlAs quantum wells (QWs) with thin InAs inserts were investigated by means of Hall effect measurements and scanning transmission electron microscopy. The analyzed heterostructures are nearly the same ones using for high electron mobility transistors manufacturing except for heavily doped contact top layer. The increase of the electron mobility and concentration in the heterostructures with thin InAs layers in the center of the InGaAs QW as compared with the uniform QW was found and this effect strongly depended on the technological conditions during growth of the InAs inserts. The dependence of the InAs insert structural quality and heterointerface width on the As4 beam equivalent pressure PAs was revealed. The decreased PAs is required for obtaining uniform and smooth InAs inserts as opposed to higher PAs resulting in the interface spreading and lateral composition inhomogeneity of the InAs insert.

The texture and deformation microstructures of Ta–2.5W alloy were investigated during cold rolling process. The microhardness can reach 280 HV when the reduction was 40%. Meanwhile, the mature body-centered cubic rolling texture was developed. The dislocation configuration appeared in a sequence from long straight dislocations and dislocation loops, followed by dislocation tangles and finally to cells boundaries and long, continuous planar boundaries. Microbands did not appear until the reduction reached 20%. The density of microbands increased with increasing reduction. The dislocations within the boundaries of microbands tended to rearrange themselves with increasing strain in a sequence from tangled dislocations, followed by parallel dislocations and finally into dislocation nets. Meanwhile, the boundaries had at least one primary set of parallel dislocations lying along the longitudinal direction of the boundaries during the whole cold-rolled process. The formation of microbands based on the double cross-slip of long straight screw dislocations was confirmed.

We compared the enhancement of photoactivity of transition metal ion (1 mol% Fe, Cu, Mn, and Zn) doped CeO2 nanocatalysts, and examined the effects of oxygen vacancies and the valence of the doped ions. The nanocatalysts were synthesized using a coprecipitation method and were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller isotherm methods and Raman spectroscopy. The photocatalytic activities of these catalysts were tested using aqueous Rhodamine B (RhB) degradation under UV irradiation. The spherical CeO2 nanocatalysts had a mesoporous structure and ∼15 nm average particle size. The catalytic activity was closely related to the oxygen vacancies and the valence of the doped ions. An increase in oxygen vacancies of doped CeO2 decreased the photocatalytic activity. The photocatalytic activities of the catalysts decreased in the order: 1 mol% Fe > Cu > Mn > Zn > undoped CeO2. The 1 mol% Fe doped CeO2 degraded ∼92.6% of the RhB after 3 h of irradiation, and the degradation obeyed pseudo-first-order kinetics. Liquid chromatography–mass spectrometry indicated that the photodegradation of RhB was a stepwise oxidation process. Under continuous oxidation, over a long reaction time, the RhB was completely oxidized to its final products, such as water and carbon dioxide.

In this study, scanning electron microscope, electron backscatter diffraction, and transmission electron microscope have been used to investigate the microstructure evolution of Cu–0.2Mg alloy during continuous extrusion in mass production. The continuous extrusion could change the size and orientation of as-cast crystallite grains of the alloy. Hardness increased gently in upsetting zone and dropped sharply in adhesion zone. Hardness reached the maximum value in right-angle bending zone; and it decreased rapidly in extending extrusion zone. Upsetting zone was mainly composed of cell blocks and microbands, and adhesion zone mainly consisted of discontinuous recrystallize grain. Shear band and subgrains were formed in right-angle bending zone due to polygonization during shear deformation. In extending extrusion zone and extrusion rod zone, recrystallize microstructures were predominant.

Single wall carbon nanotubes (SWCNTs) and liquid-phase exfoliated multilayer graphene (MLG) material thin films were assembled at a polarizable organic/water interface. A simple, spontaneous route to functionalize/decorate the interfacial assembly of MLG and SWCNTs with noble metal nanoparticles, at the interface between two immiscible electrolyte solutions (ITIES), is reported. The formation of MLG- or SWCNT-based metal nanocomposites was confirmed using various microscopic (scanning electron, transmission electron, and atomic force microscopy) and several spectroscopic (energy dispersive x-ray and Raman spectroscopy) techniques. Increasing the interfacial deposition time of the metal nanoparticles on the assembled low-dimensional carbon material increased the amount of the metal particles/structures, resulting in greater coverage of the MLG or SWCNTs with metal nanoparticles. This low-cost and convenient solution chemistry based impregnation method can serve as a means to prepare nanoscale carbonaceous material-based metal nanocomposites for their potential exploitation as electro-active materials, e.g., new generation catalysts or electrode materials.

A simple and efficient method for in situ preparation of highly stable polyimide (PI)-supported silver nanoparticles (AgNPs) was proposed. This process achieves excellent dispersion and high stability of AgNPs in the PI matrix. The formation of AgNPs in PI and the morphology evolution of PI/Ag nanocomposites were characterized by x-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy (FT-IR), and x-ray photoelectron spectra studies. The catalytic properties of these PI-supported AgNPs were investigated by monitoring the reduction of 4-nitrophenol by excess NaBH4 in water. The catalytic reaction was observed to have a pseudo first-order rate constant of 0.567 min−1 (9.45 × 10−3 s−1), which is comparable to other heterogeneous silver catalysts reported in the literature. Notably, the PI-supported AgNPs retained their relatively high catalytic activity over seven recycles with almost no leaching of catalytic species in the reaction solution. Moreover, the catalytic activity of the catalyst is still quite appreciable even after a six-month shelf-storage under room temperature.