Scanning electron microscopic (SEM) observations revealed that individual and independent microcones of sp3-bonded boron nitride grown by laser-activated plasma chemical vapor deposition were accompanied by ripple patterns spreading around them in the dimension of micrometers or sub-micrometers. The ripples were expanding equidistantly from each other and diminishing as they depart from a cone. The origin of the ripples was attributed to the interference of a direct laser cast on the plane surface and that reflected from the side of a cone; this model was satisfactorily in agreement with the SEM measurement, in which the side surface of a cone was mapped onto the plane surface surrounding the cone in the mathematical meaning of “bijection.” This micro-optical effect due to the wave nature of laser was considered to indicate and support the photochemically activated growth reactions in this process.

Poly (3-hexylthiophene) (P3HT) and aminated carbon microsphere (A-CMS) composite films with donor–acceptor architecture were prepared by spin-coating method, and the photovoltaic (PV) devices with a structure of ITO/PEDOT:PSS/P3HT:A-CMSs/Al were also fabricated. The structure and morphology of films were characterized by x-ray diffraction, Fourier transformation infrared spectrometry, ultraviolet-visible spectrophotometry, fluorescent spectrometry, and atomic force microscopy. The results indicate that A-CMSs exhibited a high LUMO energy level of −3.65 eV. The optimized blending ratio of P3HT:A-CMSs was 1:1. After annealing treatment, the intensity of absorption and the crystallization degree of the P3HT:A-CMS composite films enhanced. The polymer solar cells (PSCs) based on P3HT:A-CMS composite films showed a power conversion efficiency of 0.027% with an open circuit voltage of 0.80 V. It is suggested that A-CMS is a promising acceptor for PSCs. This would lay an experimental and theoretical foundation for the design of new acceptors for PV application.

An electro-acoustic method for measuring volume charge distributions in dielectric films (50 μm–0.2 mm thick) is described. A high voltage (>1 kV) sinusoidal signal (frequency ∼ 2 kHz) is applied across the dielectric sample. The charges inside the dielectric material will mechanically respond to the input electric signal and excite acoustic waves. The acoustic waves can be detected and measured using a piezoelectric sensor. By analyzing the received acoustic signal, we are able to compare the amount of charge in various samples.

Sodium dodecyl sulfate (SDS) was chosen as the structure controller and surface modifier for hydrothermal preparation of surfactant-modified goethite (α-FeOOH) nanorods. The as-synthesized samples were characterized by transmission electron microscopy, x-ray diffraction, Fourier transform infrared spectroscopy, Brunauer, Emmett and Teller technique, and potentiometric titration. Adsorption study using methylene blue (MB) as a model pollutant was conducted onto the surfactant-modified goethite surface. The results showed that the surfactant-modified α-FeOOH nanorods had high adsorption capacity. MB could be efficiently removed from the solution at pH 5, initial MB concentration 200 mg/L, α-FeOOH dosage 0.5 g/L, and temperature 30 °C, with 96% removal ratio. The adsorption capacity was found to be as high as 385 mg/g. The adsorption kinetic data could be described well by the pseudo-second-order model. The isothermic data were highly fitted to Langmuir isotherm. High adsorption capacity and simple reaction conditions give this novel material good prospects in future applications.

We investigated the persistent luminescence in europium-doped LiBaPO4. The persistent phosphors were synthesized via solid-state reaction method under mild reducing atmosphere. Its properties were investigated by x-ray diffraction, diffuse reflectance, photoluminescence, persistent luminescence, and thermoluminescence spectra. Under UV irradiation, broad-band persistent luminescence peaked at ∼470 nm was observed in the phosphors at room temperature. The effects of Eu2+ concentration on the persistent luminescence of LiBaPO4:Eu2+ were discussed. An energy level scheme was constructed to convey reasonable trapping and detrapping processes in the material.

The magnetic Fe–6.5 wt% Si powder was produced by gas atomization and its microstructure was also investigated. The secondary dendritic arm spacing (SDAS) is related to the droplet size, ${\rm{\lambda }} = 0.29 \cdot {D^{0.5}}$, and the numerical solidification model was applied to the system, giving rise to the correlation of microstructure to the solidification process of the droplet. It is found that the solid fraction at the end of recalescence is strongly dependent on the undercooling achieved before nucleation; the chances for the smaller droplets to form the grain-refined microstructures are less than the larger ones. Furthermore, the SDAS is strongly influenced by the cooling rate of post-recalescence solidification, and the relationship can be expressed as follows, ${\rm{\lambda }} = 74.2 \cdot {\left( {\dot T} \right)^{ - 0.347}}$. Then, the growth of the SDAS is driven by the solute diffusion of the interdendritic liquids, leading to a coarsening phenomenon, shown in a cubic root law of local solidification time, ${\rm{\lambda }} = 10.73 \cdot {\left( {{t_f}} \right)^{0.296}}$.

The effects of film thickness and surface orientation on melting behaviors of copper nanofilms were investigated by molecular dynamics simulations. A stepwise heating scheme was adopted to make sure that the nanofilms reached thermal equilibrium before further temperature increase. Melting of the nanofilms was monitored by examining the equilibrium potential energy, radial distribution function, and mean square displacement of the simulated nanofilms. From the simulation, the melting was observed to occur at a specific temperature within 1 K error, unlike the progressive melting process reported in the literature. The melted temperature and the latent heat of fusion of the nanofilms were found to increase with film thickness and approach the bulk value. The nanofilms with (111) surface have the highest melted temperature and the largest latent heat of fusion as compared to the ones with (001) and (011) surfaces, which could be explained by the lowest surface energy of (111) surface.

CuInS2 thin films with thickness ranging from 196 to 1000 nm were prepared from a source containing CuInS2 nanocrystals by using thermal evaporation method. Annealed films of CuInS2 show the quasi-amorphous to crystalline phase transition, probed through x-ray diffraction (XRD), UV-visible spectrometer, and Raman spectroscopy. From XRD, the tetragonal distortion (η) is found to be ≈1, confirming the arrangement of an extended double lattice structure of chalcopyrite phase. The surface morphology of quasi-amorphous film exhibits a very smooth surface, whereas crystalline film shows a very rough surface of CuInS2 as observed from atomic force microscopy. Crystallite size and rms roughness increase from 23 to 310 nm and from 1.5 to 36.5, respectively, with increasing film thickness as well as with increasing annealing temperature due to the crystallization process. Micro-Raman study evidencing the presence of a strong Raman A1 mode at 303 cm−1, due to the symmetric vibration of anion sublattice of CuInS2 structure. A fundamental band edge is observed in as-deposited quasi-amorphous CuInS2 films, while bulk energy band absorption and excitonic band transition are observed in crystalline films. A sharp drop in both reflectance and transmittance near the energy band gap region is observed in thick films due to a very strong absorption of crystalline phase of CuInS2.

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.

Exploiting molecular dynamics simulation, this article investigates the dynamic process of atomic rearrangement in two metallic glasses (MGs), Cu50Zr50 and Fe80P20, which are well known as ductile and brittle MGs under compression, respectively. It was found that the local rearrangements can be identified clearly by the distribution of kinetic energy and atomic strain rate, and that they are always driven by several high-velocity atoms in the core and induce a large shear and tensile strain over a very short duration. The size, kinetic energy, strain rate, and cavitation rate of the clusters in Fe80P20 are markedly larger than those in Cu50Zr50, which explains the distinct strength and brittleness of these two MGs. This study further confirmed that localized rearrangement of atomic structure is the underlying mechanism of plastic deformation in MGs, which governs their macro-scale mechanical performance.

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 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.

In this paper, a modeling method was introduced for SiC particle reinforced aluminum matrix composite. Micro-indentation technique was used to study the micro properties of both SiC particles and aluminum matrix with Micro-Compression-Tester. Mechanical properties like Young's modulus and hardness were calculated using Oliver and Pharr method. After repeated experiments, the average Young's modulus and the hardness of matrix and particle were calculated as 76.8 and 334.7 GPa, 1.58 and 32.56 GPa, respectively. During the indentation experiments on particle, the phenomenon of particle acting as “second indenter” was detected from the recorded P–h curves. Besides, the material elastic–plastic properties of matrix were analyzed using inverse method. Based on the micro material properties from indentation, the indentation processing of particle as second indenter has been simulated. Also, the simulation model at micro scale has been established by using such material properties for further investigation.

The effects of electropulsing treatment (EPT) on the recrystallization and texture of Ni9W alloy were investigated using micro-hardness and electron backscattered diffraction patterns. It is found that compared with conventional annealing, EPT tremendously accelerates the recrystallization process of Ni9W alloy. Moreover, the full recrystallization temperature of EPT is decreased by ∼180 °C. The rapid recrystallization process is attributed to the substantial increase in the atomic flux resulting from the athermal effect. EPT also significantly reduces the intensity of cube texture after full recrystallization. The evolution of recrystallization microstructure and texture reveals that EPT greatly increases the proportion of noncube oriented nuclei but has little effect on the size advantage of cube grains. It is suggested that the change of recrystallization texture results from the different effects of EPT on cube band nucleation and shear band nucleation.