In this work, the morphology of BiFeO3 was successfully modulated from microsphere to microcube by using a polyanion, poly (methyl vinyl ether-alt-maleic acid) (PMVEMA), in a microwave assisted hydrothermal route. A simple ultrasonic purification method has been developed to obtain pure phase BiFeO3 from the crude products without using any chemicals. X-ray diffraction results confirmed the capability of this purification method. When increasing the amount of PMVEMA, the morphology of BiFeO3 gradually changed from microsphere to microcube as illustrated by scanning electron microscopy. A mechanism was suggested for the morphology evolution of BiFeO3. After the formation of the small BiFeO3 single crystal, PMVEMA preferentially absorbed on one side of the crystals through specific and/or noncovalent interactions, resulting in the preferential integration of these crystals to form microcubes. The magnetic properties of these microcrystals were also investigated and the magnetization of the microcubes increased with the decrease of temperature.

Under the mixed-mode loading condition, mechanical responses of the Al-terminated O-site Ni(111)/α-Al2O3(0001) interface are investigated using first-principle calculations. The displacement-controlled loadings along 22.5, 45, and 67.5° orientations with respect to the interface are applied. The tension and shear responses of the interface are elaborated according to the computational results, including the mechanical strengths, the effect of tension softening, and the failure characteristic. In addition, the stress versus displacement relationships are derived out based on the general approach suggested by [Sun et al., Mater. Sci. Eng., A170, 67 (1993)], and the deviations between the analytical and computational results are examined in particular. Furthermore, the potential function and its development of this interface are discussed in detail.

Eu3+, Bi3+ codoped Lu2O3 powders (Eu = 2.5 at.%, Bi = 0–3.0 at.%) were prepared using the sol–gel method. Fourier transform infrared spectroscopy, x-ray diffraction, and excitation and emission spectra were carried out to characterize the synthesis, structure, and luminescent properties. The excitation spectra show a strong peak at 350–390 nm, corresponding to the Bi3+1S0 → 3P1 transition, and the emission spectra present the emission from 5D0 → 7FJ (J = 0, 1, 2, 3, 4) level of Eu3+. The intensity of the reddish emission at 612 nm was monitored as a function of the Bi3+ content and showed a light yield increment of ≈400% compared to a monodoped sample at 1.0% at. Bi3+, produced by an energy transfer process from Bi3+ to Eu3+. This was a consequence of the overlapping of the Bi3+3P1 → 1S0 emission with the f–f Eu3+ transitions.

Compound effects of B and Y additions on the microstructures and properties of a new type of high-strength and high-conductivity (HSHC) Cu–Mg–Te alloys are investigated on the aspects of purification and precipitation. Because of the purification function of B and Y additions, the tensile strength increased superlatively by the amplitude of 21.7% with a similar increase of elongation and the electrical conductivity of 4.2%. By comparison of the calculated decomposition pressures of B2O3 and Y2O3 at different temperatures, it can be concluded that the boron oxide is more stable than the yttrium oxide in the copper liquid, indicating the superior deoxygenization purification of the rare earth yttrium. The dispersive distribution of the Y–B compounds (YB6) was another factor for the improvement of the mechanical properties of the copper alloy. Finally, the copper alloy treated by hot rolling, cold rolling, and annealing processes in sequence exhibits HSHC with the tensile strength of 610.7 MPa and the electrical conductivity of 53.1%IACS.

Solutions to the technical challenge of bonding and joining bulk metallic glasses have long been sought after due to the exceptional property sets displayed by this class of engineering materials. Here, we demonstrate the ability to deposit a compositionally and functionally graded hybrid coupling layer using sol–gel processing methods to promote adhesion at the metallic glass–epoxy interface. In this study, we fine-tune the molecular composition by varying the sol Zr:Si ratio, altering film properties that consequently influence crack path selection at the interface. When optimized, up to 3-fold improvements in the adhesive/cohesive properties of these structural bond lines can be attained, with the highest GC values correlating with cohesive cracking through the hybrid. We also demonstrate the ability of these hybrid structures to significantly reduce the influence of moisture-assisted degradation as evidenced by reductions in crack growth rates of over two orders of magnitude and increased threshold limits.

In this study, gold (Au) nanowires were synthesized with a modified hydrothermal process, and high structural purity and control over Au nanowire diameter were achieved. Parametric study was performed to examine the effect of surfactant concentration, reaction time, and temperature on the quality of the synthesized products. The optimum conditions were determined for the synthesis with two different surfactant molecules, namely hexamethylenetetramine and ethylenediaminetetraacetic acid. Au nanowires synthesized under optimum conditions have high aspect ratio (diameters in the range of 50–110 nm and lengths in micrometers) with high structural purity and are potentially useful for applications such as surface-enhanced Raman scattering spectroscopy and transparent conducting electrodes for optoelectronic devices.

Ce0.35Zr0.65−xRExO2 (RE = Y and La; x = 0 and 0.10) and Ce0.35Zr0.50Y0.075La0.075O2 were prepared by a coprecipitation method. The textures, structures, oxygen storage capacity (OSC), and redox properties of all samples were investigated using Brunauer–Emmett–Teller surface area characterization, x-ray diffraction (XRD), Raman spectra, temperature-programmed technique, and oxygen pulse reaction. The results showed that the fresh Ce0.35Zr0.65O2 has cubic phase, 434 μmol/g of OSC, 82 m2/g of surface area, and good redox properties; after aging at 1000 °C, Ce0.35Zr0.65O2 still has cubic phase, 418 μmol/g of OSC, and 50 m2/g of surface area; when Y3+ or La3+ is added to CeO2–ZrO2, the aged Ce0.35Zr0.65−xRExO2 (RE = Y and La; x = 0 and 0.10) still remains cubic phase, high OSC, and large surface area (47 m2/g); when Y3+ and La3+ are simultaneously added into CeO2–ZrO2, a stable solid solution with cubic phase is formed and has 459 μmol/g of OSC; and the aged Ce0.35Zr0.50Y0.075La0.075O2 reaches to 60 m2/g of surface area and has 390 μmol/g of OSC.

A simple and modified solvothermal method using oxalate precursor, used to synthesize Cd1−xNixO (x = 0.047, 0.102, and 0.163) nanoparticles and their phase structure, morphology, optical and magnetic properties, have been investigated. X-ray diffraction studies revealed that as-prepared Ni-doped CdO solid solutions are highly crystalline and stabilized in a monophasic cubic CdO structure. X-ray diffraction and ICP-MS studies confirmed the incorporation of Ni2+ in a CdO matrix. The average grain size was found to be 30, 15, and 11 nm, respectively, using transmission electron microscopic studies. High surface area in the range of 118–143 m2/g has been achieved for these solid solutions using the multipoint BET method, which increases on increasing Ni concentration in Cd lattice site. The optical band gap of these solid solutions shows red shift to the undoped CdO. Ni-doped CdO nanoparticles exhibit co-existence of paramagnetism and ferromagnetism.

A novel kind of solid amine-containing fibrous adsorbent (PP-GMA-TETA) was prepared through irradiation grafting copolymerization with glycidyl methacrylate (GMA) onto polypropylene (PP) fiber, followed by reacting with triethylenetetramine (TETA) to introduce primary and secondary amine groups on its surface. The effects of the reaction conditions, such as the TETA concentration, temperature, and reaction time on amination degree of PP-GMA-TETA, were investigated. Adsorption capacity of PP-GMA-TETA with 77.7% amination degree could reach 4.72 mmol/g. After adsorption, the spent fiber could be completely regenerated at 100 °C by steam for 20 min and its adsorption behavior kept almost constant within six recycles. The comparison of adsorption capacities of amine fibers aminated with various aminating agents also demonstrated that fibers with higher content of primary amine would obtain faster adsorption rates and higher adsorption capacities.

In this article, ZnO microtube was prepared using mixed powder of Zn, ZnO, and carbon as source via chemical vapor deposition method. The growth process was discussed in detail, and the high Zn vapor pressure and high growth temperature were considered as two crucial factors determining the formation of tubular structure. A two-step growth model was proposed, namely initial deficient-oxidation and followed by second-volatilization. Four another experiments were further conducted to analyze the growth behavior of reagent species under different Zn vapor pressure and growth temperature, respectively. These experimental results indicated that the formation of Zn-rich structure under enough high Zn vapor pressure and second-volatilization of these abundant interstitial Zn under high growth temperature were important to form tubular structure. Our experimental method provided a feasible route to prepare other hollow structures, such as oxide, sulfide, etc. Furthermore, these synthesized ZnO microtube might have potential application as functional blocks in nanodevices.

A special type of epitaxial growth appears during solid-phase thin film reactions, where the reaction product grows epitaxially on the substrate. Some metal silicide layers and nanostructures are known to develop such epitaxial structures. In this study, iron silicide was used to study the effect of the growth mode on the epitaxial growth. Strain-induced, self-assembled iron silicide nanostructures were grown on Si(001) substrates by electron gun evaporation of 1.0 nm iron and subsequent annealing at 500–850 °C for 60 min. The growth processes were checked by reflection high-energy electron diffraction, and the formed structures were characterized by scanning electron microscopy and optical microscopy. The iron silicide nanostructures were oriented in square directions epitaxially fitting to the surface of Si(001). The shape and size of the nanostructures depended on the annealing temperature. In some cases, the nanoparticles were arranged in circles. This might be the direct consequence of a nucleation-controlled type transition of iron monosilicide to iron disilicide phase at nanoscale.

A series of Ni/C catalysts with different Ni content (15, 20, and 30 wt% Ni) were prepared by the wet incipient impregnation method. Their textural properties were studied by surface fractal dimension (D s) and nonlocal density functional theory using nitrogen sorption data. Their structural properties were studied by x-ray diffraction, Rietveld refinement, radial distribution functions (RDFs), and electron density maps of Fourier. Surface areas of Ni/C catalysts decreases slightly from 614 to 533 m2/g as Ni content increases from 15 to 30 wt%; however, the Ni crystallite size (5.1–31.4 nm) increases as the nickel content increases. Many point defects were found by Rietveld refinement in nickel nanostructures of Ni/C catalysts with 20 and 30 wt% Ni. This was confirmed by RDFs and electronic density maps. On the other hand, the hydrogen production via the photodehydrogenation of ethanol is very sensitive to the nickel crystallite size and the number Ni atoms in nickel nanostructures. The maximum reaction rate (363.64 μmol/h) is achieved on Ni/C catalyst with 15 Wt% Ni content which has the smallest crystallite size (5.1 nm) and less point defects in its nickel nanostructures. Ab initio calculations were performed to propose a reaction mechanism in the photodehydrogenation of ethanol.

This study presents a polymerization of L-lactide and poly(ethylene glycol) of various molecular weights to produce biodegradable poly(L-lactide)-poly(ethylene glycol) (L-PEG) block copolymers. The chemical structures, crystallization behavior and thermal properties of L-PEG copolymers were investigated using proton nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, gel permeation chromatography, thermogravimetric analysis and differential scanning calorimetry (DSC). The analysis of isothermal crystallization behavior of L-PEG copolymers using the Avrami equation revealed that the grain growth of L-PEG200 and 600 were unstable, jumping between one dimension and two dimensions. By contrast, the grain growth of L-PEG2000 was more stable, with a growth trend toward three dimensions. The results of L-PEG isothermal crystallization by DSC indicate that within a range of 123–127 °C, the crystallization rate was higher at lower temperatures. The values of the crystallization constants in the Avrami equation were also lower.

Precise spatial ordering of quantum dots (QDs) may enable predictable quantum states due to direct exchange interactions of confined carriers. The realization of predictable quantum states may lead to unique functionalities such as spin cluster qubits and spintronic band gap systems. To define exemplary quantum architectures, one must develop control over QD size and spatial arrangement on the sub-35-nm length scale. We use fine-probe electron beam irradiation to locally decompose ambient hydrocarbons onto a bare Si(001) surface. These carbonaceous patterns are annealed in ultrahigh vacuum (UHV), forming ordered arrays of nanoscale SiC QDs. We have achieved sub-10-nm diameter epitaxially oriented 3C-SiC nanodots with interdot spacings down to 22.5 nm. We investigate the templated feature evolution during UHV annealing and subsequent Ge epitaxial overgrowth to identify key mechanisms that must be controlled to preserve pattern fidelity and reduce broadening of the nanodot distribution.

During directional solidification of Cu–Ge peritectic alloys, a two-phase separated structure has been observed. With proper growth conditions, the peritectic ζ-Cu5Ge and primary α-Cu phases completely separate and form cylindrical layered structures. It is found that the formation of the separated structure is closely related to double diffusive convection and growth conditions. In the two-phase separated structure, a large trijunction region of peritectic reaction forms around the cylindrical α-Cu phase. During peritectic reaction, the morphological instabilities of ζ-Cu5Ge occur under high pulling velocities and are explained by the constitutional undercooling criterion. A new coupling growth between the ζ-Cu5Ge-phase and the groove of α-Cu phase near the trijunction is observed. Different from peritectic coupling growth, the diffusion coupling is established below the peritectic temperature. This two-phase separated growth process creates new opportunities for the fabrication of functionally layered materials.

During the advance of the nuclear fission reaction, fission products accumulate and form pores (gas bubbles) that decrease the thermal conductivity of the nuclear fuel, potentially leading to overheating of the fuel element. To investigate this important phenomenon, a finite-element method is used to simulate the effect of 3-dimensional (3D) distributions of pores on the thermal transport in a nuclear fuel element consisting of uranium oxide (UO2) nuclear fuel pellet and Zircaloy cladding. Spherical pores ranging in size from 70 to 172 µm are introduced to create up to 30 vol% total porosity. The simulations demonstrate that the centerline temperature increases with the total porosity and the increase is nonlinear. The results also show that the centerline temperature, at fixed total porosity, weakly depends on the pore size distribution. This method can provide useful information regarding the effect of high porosity levels that may occur in off-normal operation conditions.