Anelastic recovery of pure magnesium was monitored quantitatively by means of acoustic emission (AE) in cyclic compression–quick unloading–recovery process. The influences of grain size, strain rate, and the strain-controlled cyclic process on anelastic recovery were analyzed in details. A detwinning model in anelastic recovery process was proposed, and the results showed good agreement with the experimental data. Three stages of anelastic recovery behavior as a function of strain were observed: stages I and III were considered to be dominated by various detwinning processes and stage II was dominated by thermal motion of dislocation. A quantitative relationship between anelastic recovery strain and AE signals was obtained, and from which the anelastic recovery strains from dislocation motion and detwinning were separated for the first time. In the strain-controlled cyclic process, both the amount of AE signals and the anelastic recovery strain were observed to decrease while the fraction of anelastic recovery strain from dislocation motions was observed to decrease more rapidly than that from detwinning with increasing cyclic number.

Molecular films have been extensively used for crystal growth. The Langmuir–Blodgett (LB) technique allows the oriented molecules film to be produced in a controllable manner. By controlling the LB film surface pressure and tuning quenching temperature of the supersaturated solution, single NaCl (100) crystal planes are successfully produced under the surface pressure of 30 mN/m with quenching temperature 5 °C of the NaCl supersaturated solution. The mechanism of single NaCl (100) crystal growth can be further explained based on the best matching between NaCl (100) crystal plane distance and the lattice parameter of LB film among all other crystal planes.

Blister-actuated laser-induced forward transfer (BA-LIFT) is a direct-write technique, which enables high-resolution printing of sensitive inks for electronic or biological applications. During BA-LIFT, a polymer laser-absorbing layer deforms into an enclosed blister and ejects ink from an adjacent donor film. In this work, we develop a finite element model to replicate and predict blister expansion dynamics during BA-LIFT. Model inputs consist of standard mechanical properties, strain-rate-dependent material parameters, and a parameter encapsulating the thermal and optical properties of the film. We present methods to determine these material parameters from experimental measurements. The simulated expansion dynamics are shown to be in good agreement with experimental measurements using two different polymer layer thicknesses. Finally, the ability to model high-fluence blister rupture is demonstrated through a strain-based failure approach.

Porous zirconium metal microspheres were synthesized successfully by a combustion technique using ZrO2 + 2Mg starting mixture. In this process, a controlled amount of KClO3 + 3Mg is mixed with ZrO2 + 2Mg to enable a self-sustaining combustion process and to promote a reduction of the ZrO2. The framework structure, morphology, and porosity of zirconium microspheres were determined using various techniques. Microscopic visualization suggested that the spherical structure has macroporous windows of diameter ∼0.5–5.0 μm and the space between the macropores has a wormhole-like mesoporous/microporous structure. The mesoporous structure had a pore diameter of ∼1.19 nm. This procedure provides an easy method for the synthesis of porous microspherical assemblies of Zr composed of submicrometer size particles.

The bipolar plate is one of the most important components in proton exchange membrane fuel cell. In this article, the graphite/polymer composite bipolar plates have been developed by compression molding technique. The study on effects of different resin types on the electrical conductivity, mechanical property, and corrosion performance of the composite bipolar plates shows that the properties of graphite/novolac epoxy (NE) plate are all better than those of graphite/phenol formaldehyde resin plate. The triple continuous structure provides graphite polymer blends with high electrical conductivity, high flexural strength, less porosity, and high density. Most of the properties, such as electrical conductivity, flexural strength, water adsorption, porosity, and so on, are affected by the properties of the polymer. The graphite/NE composite bipolar plate when used in the unit fuel cell assembly showed single-cell performance comparable to that of the commercially available graphite bipolar plates.

Here, we describe the synthesis of novel titania nanosheets controllably doped with binary transition metal ions and their layer-by-layer self-assembly. The tailored Mn and Fe doping in exfoliated Ti0.6Mnx/2Fe(0.8-x)/2O2 (x = 0.0–0.4) nanosheets is achieved by systematically changing the molar ratio of Mn/Fe in K0.8Ti1.2MnxFe0.8-xO4 using a codoping strategy. The protonated layered crystals exhibit a delaminated behavior in the tetrabutylammonium hydroxide solution and are exfoliated into colloidal single sheets, which are characterized by a large lateral size and a thickness in molecular dimension. The resulted nanosheets are able to be layer-by-layer deposited with oppositely charged polymers into a composite organic/inorganic system.

BaZrO3–BaTiO3 ceramics exhibit a shift in transformation temperatures as revealed by dielectric and viscoelastic spectroscopy; a phase diagram has been established. Sigmoid anomalies in Poisson’s ratio and bulk modulus during the ferroelastic transitions were observed in doped materials, which are not predicted by standard theories for phase transformations. “Hashin–Shtrikman” composite model with negative stiffness heterogeneity can well explain this phenomenon. Negative stiffness heterogeneity is considered to be caused by the strained BaTiO3 unit cells in the vicinity of BaZrO3-rich zones under the perturbation of lattice reconstruction.

Silicon oxide has been widely used to encapsulate biomolecules to preserve their activity in less than ideal environments. However, there are other inorganic oxides with inherent properties that would be advantageous in creating a multifunctional material. Titanium oxide exhibits properties that have applications in areas such as electronics, energy conversion, and decontamination. Herein is reported the formation of titania coatings fabricated on polymer beads using a biomimetic approach and characterized with scanning electron microscopy and energy dispersive x-ray spectroscopy. The approach involves the use of functionalized polymer beads, which initiate oxide formation from a water-soluble titanium complex. The method was used to encapsulate the enzyme diisopropylfluorophosphatase, in situ, within the oxide matrix under buffered aqueous conditions while retaining its enzymatic activity against diisopropylfluorophosphate. In addition, the biomimetically produced titania was shown to exhibit UV-assisted degradation activity against an ethidium bromide dye, upon liberation from the coating template.

Second nearest-neighbor modified embedded-atom method (MEAM) interatomic potentials for the Al–H and Ni–H binary systems have been developed on the basis of previously developed MEAM potentials of pure Al, Ni, and H. The potentials can describe various fundamental physical properties of the relevant binary alloys (structural, thermodynamic, defect, and dynamic properties of metastable hydrides or hydrogen in face-centered cubic solid solutions) in good agreement with experiments or first-principles calculations. The applicability of the present potentials to atomic level investigations of dynamic behavior of hydrogen atoms in metal membranes is also discussed.

This work investigated the cell labeling of 12-nm meso-2,-3-dimercaptosuccinic acid (DMSA)-coated Fe3O4 magnetic nanoparticles with multiple mammalian cells. Six different cells, including RAW264.7, Hepa1-6, THP-1, HepG2, HeLa, and HL-7702, were treated with the nanoparticles at various concentrations (20~100 μg/mL) for different times (2~72 h), and the labeling effect was evaluated by observing the intracellular internalization of the nanoparticles with Prussian blue staining and measuring the corresponding cellular iron loading with colorimetric assay. The results demonstrated that the nanoparticles could label all cells studied. However, the labeling efficiency was not the same between different cells, which depended on the cell types, the nanoparticles’ concentration, and the time of treating cells with the nanoparticles. In comparison, RAW264.7 was labeled more effectively than other cells at any concentration of the nanoparticles. The iron loading of RAW264.7 significantly increased with the concentration of the nanoparticles and the treatment time. However, both human liver cells (HepG2 and HL-7720) were labeled with the lowest iron loading. The measurement of cell viability revealed that the growth of all cells was not affected by the nanoparticles at a common in vivo application dose of iron nanoparticles (30 μg/mL), demonstrating that the nanoparticles have better biocompatability.

Polyaniline nanofiber (PANF) was synthesized using interfacial polymerization and was mixed with aqueous solution of poly(vinyl alcohol) (PVA) to form PANF–PVA binaries. The PANF suspension in water could be stabilized by PVA for more than 3 months due to the hydrogen bonding interaction between PANF and PVA. The specific characteristics of PANF–PVA films was checked by scanning electron microscopy, conductivity measurement, thermogravimetric analysis, Fourier transform infrared spectroscopy, and cyclic voltammetry. The composite film contained 25 wt% PVA (PANF–PVA25) casting at 105 °C was found to have a porous structure and good conductivity. The presence of hydrogen bonding interaction between PANF and PVA improves the electroactivity and electroactive stability of PANF–PVA25 for electrochemical applications. However, an ether linkage between PANF and PVA polymer chain was also found as casting the PANF–PVA film at 200 °C, which is unfavorable for electrochemical applications.

The effects of water vapor and oxygen on the cyclic fatigue behavior of oxygen-excess La0.8Sr0.2MnO3+δ (LSM) were investigated under three-point bending at 1273 K. Because the fatigue life did not obviously depend on the number of cycles, which also represented the effective time of the applied stress, the fracture was presumed to not be significantly controlled by stress-corrosion cracking. Under a low oxygen partial pressure (), however, wet exposure inhibited both fatigue fracture and permanent deformation, in which the LSM crystal lattice was distorted and the unit cell free volume was reduced. Under a high , on the contrary, the crystal symmetry was increased by the wet exposure. The inhibition of fatigue fracture and deformation at both high and low was probably caused by retardation of lanthanum diffusion through its vacancies.

Theoretically dense ZrB2–SiC two-phase microstructures were isothermally oxidized for ∼90 min in flowing air in the range 1500–1900 °C. Specimens with 30 mol% SiC formed distinctive reaction product layers that were highly protective; 28 mol% SiC–6 mol% TaB2 performed similarly. At and above 1700 °C, the composition with only 15 mol% SiC oxidized extensively because of deficient silicate liquid formation. Specimens with 60 mol% SiC were resistant to oxidation up to 1800 °C; at 1900 °C, this composition displayed periodic ruptures of the passivating layer by emerging gas bubbles. Oxide coating thicknesses calculated from weight loss data were consistent with those measured from scanning electron microscopy micrographs. A layer of ZrB2 devoid of SiC was argued to be from preferential removal of SiC by reaction of a silica oxidation product with adjacent unreacted SiC to form escaping gases.

Welded joints of P92 steel subjected to creep testing at 650 °C and 70 MPa were investigated. Type IV cracking was observed in the fine-grained heat-affected zone (FGHAZ) of the welded joints by optical microscopy. It was found that with varying creep times, the number of creep voids increased at an accelerating rate and the maximum number of voids was formed in the FGHAZ. Scanning electron microscopy observations revealed that precipitates were formed in the interior of creep voids, suggesting that the nucleation of the creep voids is related to the precipitates. These creep voids then connected with each other, isolated the grain from the matrix, and formed zigzag microcracks, leading to type IV cracking. New coarse carbides—the Laves phase and Cr7C3—were precipitated during creep. These carbides can deteriorate the creep strength and stimulate the nucleation of creep voids in the FGHAZ.

A model is developed to analyze the microstructure evolution in a continuously solidified hypermonotectic alloy. The model takes into account the common actions of the nucleation and diffusional growth/shrinkage of the minority phase droplets, the spatial phase segregation, and the convections of the melt. The microstructure formation in a continuously solidified hypermonotectic alloy is calculated. The numerical results demonstrate that the convections have great effect on the microstructure formation. The convective flow against the solidification direction causes an increase in the nucleation rate while the convective flow along the solidification direction causes a decrease in the nucleation rate of the minority phase droplets. The convections lead to a more nonuniform distribution of the minority phase droplets in the melt. It causes an increase in the size of the largest minority phase droplets and is against the obtaining of the hypermonotectic alloys with a well-dispersed microstructure.