Fe–Mn–Pd alloys are promising candidates as biodegradable material for use in temporary implant applications. In this study, the hardening phase of Fe-rich martensitic alloys containing 1, 3, and 6 wt.% Pd and a fixed Mn content of 10 wt.% was investigated. All of these alloys show considerable age-hardening upon isothermal aging at 500 °C, exhibiting a behavior characteristic of maraging steels. Atom probe tomography (APT) and x-ray diffraction (XRD) measurements were performed to characterize the composition and crystallography of nanometer-sized precipitates forming in the overaged region of the Fe–Mn–Pd alloys. The precipitates consist mainly of Mn and Pd and the peaks of the intermetallic particles observed in the XRD spectra can be ascribed to the face-centered tetragonal β1-MnPd phase. The precipitation sequence for Fe–Mn–Pd is revealed to be similar to that reported for Fe–Mn–Ni and Fe–Mn–Pt maraging steels.

The submicrometer Ni cones have been successfully prepared through a simple solvothermal method in glycerol. The as-prepared products were extensively characterized by x-ray diffraction, field emission scanning electron microscopy, energy-dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The effects of the volume ratios of glycerol to water, and the concentration of alkali on morphologies of Ni samples were investigated. The electromagnetic wave absorption properties of Ni cones were evaluated based on the relative complex permeability (μr) and permittivity (εr). A minimum reflection loss (RL) of −41.6 dB was observed at 4.7 GHz with the thickness of 3.8 mm and the RL values below −10 dB were obtained in the range of 3.9–15.0 GHz with the corresponding thickness of 1.8–3.8 mm. The excellent wave absorption properties of the obtained products are due to the synergic effect of dielectric loss and magnetic loss, geometry effect and unique morphology.

The study demonstrates the 100% repeated recyclability of hybrid membranes without any pretreatment. Composite membranes designed with titanium dioxide (TiO2) nanoparticles (NPs) and polysulfone (PSf) membranes were used for reduction of chromium (Cr) (VI) to Cr (III) under sunlight. Different concentrations of TiO2 NPs varying from 1.5% to 2.5% with the difference of 0.5% were incorporated into the membrane matrix. Increase in weight percentage of TiO2 particles enhances the reduction to 100% within 2.5 h with an increase in recyclable capacity as well. The effect of recycling on the surface of the membrane was studied using x-ray diffraction (XRD), scanning electron microscope (SEM), and atomic force microscopy (AFM). The observations in general indicate an increase in roughness without affecting the catalytic efficiency up to six recycles. The study on surface membrane morphology and catalytic efficiency with reusability opens a scope for a feasible economical chromium reduction via a membrane process. Macro and micro structure of the membrane before reduction and after recycling were studied and compared with scientific evidence. Based on the results, the kinetic model was proposed for the reduction reactions.

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 modification of near-eutectic Al–Si alloy with samarium additions (0–0.9 wt.% content) has been studied. The thermal analysis results indicated that the addition of Sm in Al–12Si alloy caused a depression of eutectic temperature (∆T E). And it was found that Sm was capable of breaking down the primary α-A1 phases, giving rise to an increment in the number of dendrites. Simultaneous primary Si refinement and eutectic modification were achieved by Sm addition. When 0.6 wt.% Sm was added to the alloy, the silicon in Al–12Si alloy was best refined and showed a fully modified, fine fibrous eutectic structure; the primary α-Al phase appears as a slightly dual dendritic-cellular nature and a pine-tree structure. Moreover, the mechanical properties were investigated by the tensile test. A good combination of ultimate tensile strength (217 MPa) and elongation (1.3%) was obtained when the addition of Sm was up to 0.6 wt.%.

By using microemulsion-mediated solvothermal method in the presence of camphorsulfonic acid as a dopant, self-aggregated polyaniline (PANI) nanowires were synthesized and further organized into three-dimensional cluster-connected networks. So-formed PANI exhibited a hierarchically porous structure, which was significantly different from those obtained by conventional chemical oxidation method, hydrothermal method, and other reported methods. Compared with nanofibers presented in this study, the nanowires in the clusters had a great decrease in diameter from ∼60 to ∼15 nm due to the space-confined polymerization. In addition, the size of the clusters could be easily adjusted by altering the dopant/monomer molar ratio. A probable assembly mechanism for such an interesting morphology was proposed. Used as an electrode material, PANI clusters showed high specific capacitances (510 and 368 F g−1 at 0.5 and 2 A g−1, respectively) and improved cycling stability (66% capacitance retention over 1000 cycles) as compared to PANI fibers and particles obtained by other methods, which may be related to its unique morphology and high doping level.

Single-walled carbon nanotubes (SWCNTs), which have a unique electronic structure, nanoscale diameter, high curvature, and extra-large surface area, are ideal for making a new class of nanocomposites. In this study, under the condensed phase optimized molecular potentials for atomistic simulation studies force field, classical molecular dynamics simulation is used to study the molecular interactions between SWCNTs and the molecules of binaphthyl core-based chiral phenylene dendrimers (G0–G2). The simulation results revealed that both G2 and G1 molecules have obvious attractive interactions with SWCNTs, and theoretically demonstrated the possibility of noncovalent functionalization of SWCNTs with chiral dendrimers. The influence of temperature on composites was also studied, and the results indicate that the interaction decreases strongly for SWCNTs@G1 and SWCNTs@G2 with increasing temperature. The possibility during real-world composite processing would create the desired structure bridges between nanotubes and chiral dendrimers, which can be used to produce nanocomposites such as highly sensitive as well as enantioselective fluorescent sensors.

One of the barriers for wide usage of hydrogen energy system is efficient storage. To store more hydrogen efficiently, physisorption is a choice among the others with high storage performance, reversibility, and lifecycles. Metal organic framework (MOF) structured organometallic orotate-Co(II) complexes could serve as sorbents which store hydrogen by physisorption. In this work, mono- and bidentate MOF structured orotate-Co(II) complexes are synthesized, characterized, and then investigated for hydrogen storage experimentally and theoretically. It is found that these compounds could store hydrogen. Especially, the monodentate complex could uptake hydrogen better than the other. Storage performances for mono- and bidentate complexes were 0.80 and 1.15 wt% at 77 K and approximately 80 bars experimentally, 1.03 and 1.16 wt% theoretically for the same conditions.

High rate of charge carrier recombination is a critical factor limiting the photocatalytic activity of g-C3N4. In this contribution, we demonstrate that this issue can be alleviated by constructing a plasmonic photocatalyst with tailored plasmonic-metal nanostructures, i.e., core–shell-typed Ag@SiO2 nanoparticles. Compared with pure g-C3N4, the photocatalytic hydrogen production activity was enhanced by 63% for Ag@SiO2/g-C3N4. As analysis from the photoluminescence results, the enhancement could be attributed to that plasmonic nanostructures favored the separation of electron–hole pairs in the semiconductor due to localized surface plasmons resonance effect. It was found that the silica shell between the Ag nanoparticles and g-C3N4 was essential for the better photocatalytic activity of Ag@SiO2/g-C3N4 than that of Ag/g-C3N4 by limiting the energy-loss Förster energy transfer process.

Phonon thermal conduction was explored and discussed through a combined theoretical and simulation approach in this work. The thermal conductivity κ of polycrystalline graphene was calculated by molecular dynamics simulations based on a hexagonal patch model in close consistency with microstructural characterization in experiments. The effects of grain size, alignment, and temperature were identified with discussion on the microscopic phonon scattering mechanisms. The effective thermal conductivity was found to increase with the grain size and decrease with the mismatch angle and dislocation density at the grain boundaries (GBs). The ∼T−1 temperature dependence of κ is significantly weakened in the polycrystals. The effect of GBs in modifying thermal transport properties of graphene was characterized by their effective width and thermal conductivity as an individual phase, which was later included in a predictive effective medium model that showed degraded reduction in thermal conductivity for grains larger than a few micrometers.

The effect of the intercritical temperature on the microstructure and mechanical properties of a newly developed quenching and partitioning steel using martensitic microstructure prior to the heat treatment process was studied. Such a quenching and partitioning process possessed a unique microstructure evolution, especially during intercritical annealing after prequenching. Excellent mechanical properties were obtained due to this unique multiphase microstructure. Significant amount of interlath-retained austenite was acquired and the relationship between the microstructure and work-hardening behaviors was proposed. The martensite/austenite islands increased at elevated annealing temperature, which deteriorated the total elongation and increased the tensile strength as hard constituents when it was excessive. The result indicated that the present full martensitic microstructure before the intercritical annealing is probably more suitable to an industrial application and is a better way to produce high strength steels with suitable ductility.

Fibrous polyethylene terephthalate (PET) was modified by organometallic vapor exposure to form hybrid materials with unique photoluminescent characteristics. Using a sequential vapor infiltration (SVI) process, the elongated exposures of trimethylaluminum (TMA) to PET were examined. As the infiltration temperature increased, the evidence of changes in the reaction between the organometallic vapor and the polymer was observed as well as significant changes in the infiltration depth into the polymer fiber, owing to the variation in the reaction mechanisms of the hybrid material formation. At TMA exposures of 60 °C, the mass of the polymer fiber increased by ∼55 wt%, whereas exposures at 150 °C were limited to ∼25 wt% infiltration. Photoluminescence analysis of PET after TMA infiltration shows an intensity increase of up to ∼13x and an increase in red shift with increasing infiltration temperature, attributed to the variations in the reaction mechanism to form the hybrid modification observed through the spectroscopy analysis.

Measurements of stress evolution during low-energy argon ion bombardment of Si have been made using a real-time wafer curvature technique. During irradiation, the stress reaches a steady-state compressive value that depends on the flux and energy. Once irradiation is terminated, the measured stress relaxes slightly in a short period of time to a final value. To understand the ion-induced stress evolution and relaxation mechanisms, we account for the measured behavior with a model for viscous relaxation that includes the ion-induced generation and annihilation of flow defects in an amorphous Si surface layer. The analysis indicates that bimolecular annihilation (i.e., defect recombination) is the dominant mechanism controlling the defect concentration both during irradiation and after the cessation of irradiation. From the analysis, we determine a value for the fluidity per flow defect.

It is known that polymers used in laser sintering (LS) change their intrinsic properties due to processing conditions that are close to the crystalline melting temperature. This paper evaluates the aging behavior of a thermoplastic polyurethane powder, comparing with to a commercially available LS elastomeric material (Duraform®Flex, 3D Systems). To represent a realistic production environment, the materials were aged during 14 processing cycles in the LS process without refreshing with virgin material. Following each aging cycle, both the powder and the sintered parts were examined for chemical and physical aging effects. The results showed that the materials observed could be used without refreshing throughout the 14 aging stages, however, changes in the processing behavior as well as in the parts' mechanical properties were evident. These changes were due to the differing aging states of the LS-powder showing an increase in the particle size affecting the bulk materials packing density. Modifications in the rheological properties can be seen in a decrease of molecular weight likely to reduce the mechanical strength of tensile specimens.

To produce the magnetic core of electric motors, nonoriented electrical steels (NOESs) are used with an electrically insulating coating applied to the surface. Residual stress is induced during the coating process, which will alter the hardness and magnetic domain structure of the NOES. In this study, the effect of the coating is examined, specifically, its role in creating a residual stress near the coating/steel interface. This stress was investigated by the nanoindentation technique. With this method, a ∼30 µm deep affected area was observed for NOES along both the rolling and transverse cross section directions, when in the presence of the coating. A biaxial tensile stress of ∼200 MPa was calculated from the measured hardness values in the NOES, which was linked to variations in the magnetic domain structure near the interface. The observed magnetic domain structure was simplified by the reduction of supplemental domain structure near the coating/steel interface.

(Cu0.47Zr0.45Al0.08)100–xDyx (x = 0, 1, 2, 3, 4; at.%) metallic glasses with greatly enhanced glass-forming ability (GFA) and plasticity were synthesized based on microalloying technique. The structure, thermal stability, and elastic properties of the BMG samples were studied by x-ray diffraction (XRD), differential scanning calorimetry (DSC), and ultrasonic measurements, respectively. With addition of minor dysprosium (Dy), fully metallic glassy rods with diameters exceeding 20 mm could be successfully fabricated by copper mold casting. In addition, the Cu–Zr–Al–Dy BMGs exhibit good mechanical properties under a compressive deformation mode, i.e., high yield strength of 1735–1906 MPa, Young's modulus of 85–100 GPa, and distinct plastic strain up to 4.02%. The strength and plasticity show remarkable correlations with glass transition temperature and Poisson's ratio, respectively. The role of minor Dy addition in enhancement in GFA and mechanical property of the Cu-rich BMGs is also discussed.

A simple one-pot hydrothermal approach that allowed the selective synthesis of complex ZnO architectures with varying configurations without using any surfactants and/or solid templates is proposed in this paper. The ZnO configurations include spherical aggregates, nanosheet-based flowers, microrod-composed flowers, and nanopetal-built flowers. Kinetic factors (i.e., the base type and base/Zn2+ molar ratio) can be easily utilized to control the oriented attachment and growth of [Zn(OH)]2− on the (001) polar planes, thereby regulating the morphology of ZnO architectures. The ZnO architectures were characterized by scanning electron microscopy, transmission electron microscopy, selected-area electron diffraction, x-ray diffraction, and specific surface area. The relationships between the structures and microwave electromagnetic properties were established. Enhanced dielectric and absorption properties were exhibited by ZnO flowers composed of large-aspect-ratio microrods. Such properties could be attributed to the improved microcurrent attenuation and interface scattering rather than the dielectric relaxation and microantenna radiation. This study provides a guide for creating and synthesizing highly efficient microwave absorbing materials.

To reinforce the reliability issue brought by excessive interfacial reaction with the dimensional scale-down of electronic device, an electroless Ni–P–ZrO2 (17.5 at.% of P) composite coating was developed as the under bump metallization (UBM) for lead-free solder interconnect. ZrO2 nanoparticles were proved to be homogeneously distributed and helped improve wetting ability of the layer. Both Sn–3.5Ag/Ni–P–ZrO2 and Sn–3.5Ag/Ni–P solder joints were prepared and aged at various conditions to study the interfacial reaction. Growth of intermetallic compounds (IMCs) without serious spalling in solder/Ni–P–ZrO2 joint was slowed down because of the barrier property of incorporation of ZrO2 nanoparticles, which blocked the diffusion of Ni and Cu atoms. Based on the IMC growth, the activation energy of solder/Ni–P–ZrO2 was estimated to be higher than that of plain solder joint. The top-view of IMCs demonstrated a much finer grain size compared with that of solder/Ni–P joint. A reactive diffusion-induced compound formation mechanism was proposed to address the microstructural evolution in detail. Moreover, solder/Ni–P–ZrO2 joint demonstrated higher shear strength than did solder/Ni–P joint for different aging durations. The fracture surface of solder/Ni–P joint after shear test showed ductile transition failure, with big dimples and plastic deformation.

Plate-shaped Gd2O3 nanoclusters (GNCs) with well-controlled loading were fabricated by using amphiphilic poly(maleic anhydride-alt-1-octadecene) (PMAO) grafted with PEG as nanogel. The hydrodynamic size of the obtained GNCs was well controlled to <260 nm under appropriate emulsion process conditions and they showed excellent long-term dispersibility in phosphate buffer saline. MRI measurements clearly indicated the substantial improvement in T1 effect of the nanoclusters as compared with the individual Gd2O3 nanoplates. The obtained GNCs possessed a high r1 value of 7.948 s−1mM−1 [Gd], which is 2.23 times higher than that of the commercial product Gd-DOTA, and low r2/r1 of 1.04. In vitro test of the obtained GNCs was demonstrated in NIH/3T3 cell lines, and clear T1-weighted images were obtained. Thus, the PMAO-g-PEG assisted GNCs were potentially useful for T1-weighted MRI contrast agents.

Tungsten carbide (WC) particle–reinforced iron matrix surface composites with different content of Cr were fabricated using vacuum evaporative pattern casting technique. It was found that the morphology of carbides changed from continuous net-shape to isolated block-shape patterns. The amount of carbides increase with the increasing Cr content in the matrices. Composites with different Cr content show better abrasive wear resistance than those without Cr. With the increase of Cr content in the matrices, the three-body abrasive wear resistance of the composites increased, while the impact abrasive wear resistance of the composites increased under 1 J impact load, but first increased and then decreased under 3 J impact load. The influences of the addition of Cr in the matrices on the abrasive wear resistance were the synergistic effects of two protecting effects and two supporting effects. The results might provide significant references for the design and practical application of WC particle–reinforced iron matrix surface composites.