Inorganic oxides exhibit numerous applications influenced by particle size and morphology. While industrial methods for forming oxides involve harsh conditions, nature has the ability to form intricate structures of silicon dioxide (silica) using small peptides and polyamines under environmentally friendly conditions. Recent research has demonstrated that these biomaterials will precipitate other inorganic oxides, such as titanium dioxide (titania). Using the diatom-derived R5 peptide, new peptides with systematic changes (e.g., truncation and substitution) in the R5 primary structure were surveyed for reactivities and the impact on the morphology of the titania. The results demonstrated that (i) basic residues are vital to initiating the reaction, and a minimum local concentration is necessary to sustain the precipitation, (ii) residues containing hydroxyl side chains are important to imparting morphological control on the precipitate, and (iii) buffer conditions can dramatically alter both precipitation and morphology.

Sn doped TiO2 (SDT) hierarchical nanorods have been synthesized by using nanocystalline cellulose nanorod as biotemplate. Experimental results show that the phase transition from anatase to rutile can be realized by increasing the calcination temperature. In contrast to enhancing the calcination temperature, the Sn doping can more effectively improve the phase transition with remaining morphology due to the similar ionic radius and charge between Sn and Ti. The crystallinity, electronic structure, interface charge transfer process, and the specific surface area have a strong effect on the photocatalytic activity of the hierarchical TiO2 and SDT nanorods. Furthermore, the photocatalytic activity of SDT hierarchical nanorods can be obviously improved by loaded Au nanoparticles on the surface due to the local surface plasmon resonance effect of Au and formation of a Schottky barrier at the Au/TiO2 interface, which is in favor of the effective separation of photoinduced carriers and the formation of superoxide anion radicals.

A novel core–shell particle that consists of epoxide-terminated hyperbranched polymer (HBP) and silica nanoparticles was incorporated into an epoxy/hydroxyl-terminated HBP blend to fabricate a high-performance epoxy thermoset. The effect of the core–shell particle content on the mechanical properties of the epoxy thermosets was investigated in detail. Results from tensile, flexural, and impact tests are provided. The impact fracture surface was studied by field emission-scanning electron microscopy. The incorporation of 2 wt% core–shell particles improved the tensile strength, percent elongation at break, flexural strength, and impact resistance of epoxy/hydroxyl-terminated HBP thermosets. Field emission-scanning electron micrographs showed that core–shell particle addition resulted in large-scale shear deformation and debonding from the epoxy matrix, and improved the epoxy resin toughness.

Thermoluminescence (TL) and radioluminescence (RL) spectra of the long-lasting phosphorescence of SrA12O4:Eu2+,Dy3+ with A1N addition and commercially used SrA12O4:Eu2+,Dy3+ were compared. Their spectra were slowly recorded over the temperature range from 25 to 673 K (400 °C). A1N offers a higher temperature TL peak, which should lengthen the phosphor lifetime. However, both TL and RL, especially that below room temperature, reveal that there are additional decay paths for the samples of SrA12O4:Eu2+,Dy3+ with A1N additions. These new defect sites reduce the phosphor efficiency. Some speculative models of potential sites are proposed and discussed. In addition, discontinuous intensity changes have been observed for both sample types in TL and RL spectra, which are assigned to the transitions of embedded impurity phases. The justification for this model is explained. Suggestions for future experimentation are also considered.

The mechanical behavior of superconductor lamellar-like BaFe2As2 single crystals was investigated at nanoscale by instrumented indentation. The unique responses of the ab- and a(b)c-crystallographic planes were discussed based on their influence in hardness (H) and elastic modulus (E). The results allowed two main conclusions. (i) The choice of testing parameters strongly affected the scaling of mechanical properties on the lamellar surfaces. Lamellar cracking was the leading mechanism of deformation, featuring a brittle-like behavior and affecting considerably H and E. However, the plastic deformation history allowed different elastic–plastic responses on the ab-plane owing to the compaction of the material. Threshold loads for cracking depended on both loading rate and penetration velocity, pointing out to time-dependent plastic deformation mechanisms. (ii) Proper estimates were achieved for H in multiple loading tests [3.4 GPa for ab- and ∼1 GPa for a(b)c-planes], and for E under loads less than 3 mN (∼55 GPa for both planes).

The Manganese dioxide/reduced graphene oxide (MnO2/RGO) double-shelled hollow microsphere with an improved electrical conductivity and accessible surface area has been synthesized using the monodispersive polystyrene (PS) microsphere as a self-sacrificing template. RGO/PS core–shell microsphere was prepared through π–π stacking interaction between PS microsphere and graphene oxide sheet, and then chemical reduction using hydrazine hydrate. MnO2/RGO/PS core-shell-shell microsphere was prepared through in situ chemical redox process between KMnO4 and benzyl alcohol-anchored RGO/PS. MnO2/RGO double-shelled hollow microsphere was obtained by etching PS microsphere from MnO2/RGO/PS using tetrahydrofuran. It had a pore diameter of 560–580 nm and layer thickness of 210–270 nm. Low charge transfer resistance of 0.3006 Ω and total electrochemical impedance of 2.37 Ω caused a high specific capacitance of 450.1 F g−1 at 0.2 A g−1. The capacitance retention of 81.7% after 1000 cycles indicated good cycling capability at 5 A g−1. MnO2/RGO double-shelled hollow microsphere presented the promising application for supercapacitor electrode material.

A new red-emitting phosphor, Eu3+ doped Al5BO9, was prepared for the first time by calcining the precursor of K2[Al(B5O10)]·4H2O:Eu3+ which was synthesized by a facile hydrothermal route. The obtained samples were characterized by energy dispersive x-ray spectrometer, x-ray powder diffraction, IR, scanning electron microscopy, photoluminescence, and photoluminescence excitation spectrum (PLE). Moreover, the influences of Eu3+ doping concentration, calcination temperature, and calcination time on the luminescence properties of Al5BO9:Eu3+ phosphor were also investigated. The phosphor with optimal luminescent intensity and the higher red/orange ratio was obtained by sintering the precursor at 1300 °C for 5.5 h, with 5% doping concentration, in which its luminescent decay lifetime and quantum efficiency were also measured. It is also found that the phosphor prepared by conventional solid-state reaction method exhibits the dominant transition at 591 nm (orange) with the lower color purity, while the phosphor prepared by the present precursor method exhibits the dominant transition at 615 nm (red) with the higher color purity, which indicates that this is a good method for preparing Al5BO9:Eu3+ red phosphor.

Three important low valent transition metal oxides were synthesized in supercritical methanol by using inorganic metal salts as precursors. X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and x-ray photoelectron spectroscopy were applied to analyze the composition, structure, and morphology of the products. Results showed that Cu2O, MoO2, and V2O3 were obtained successfully under a supercritical condition of 240 °C and 9.0 MPa. MoO2 and V2O3 displayed sphere-like morphology with average particle sizes of 20–40 and 20–50 nm, respectively. Cu2O particles displayed edge-truncated cubic morphology with a particle size of 2.5 μm. Formation mechanism proposed that high valent metal oxides (CuO, MoO3, and V2O5) were formed firstly in supercritical methanol by the decomposing of precursors and then reduced to target products by free hydroxyl anions. In addition, methanol performed important roles not only as a reaction medium but also as a reducing agent under supercritical fluid conditions.

To improve photocatalytic activity of TiO2, 3-hexylthiophene monomers were in situ polymerized on porous TiO2 nanocrystalline thin film. Poly-3-hexylthiophene (P3HT) was homogenously modified on the thin film. The surface modification amounts of P3HT were controlled using different concentrations of 3-hexylthiophene monomer ether solutions and detected by the absorption spectra. The photocatalytic performance tested in methyl orange solution under ultraviolet light irradiation was significantly enhanced due to the modification of P3HT. Within 210 min, approximately 80% of methyl orange was degraded for the modified film with the optimized modification amount, it is twice higher than that of the film without modification. Photoluminescence spectra and open-circuit voltage decay processes of the samples were measured to demonstrate the photocatalytic activity enhancement mechanism due to the in-situ polymerization of P3HT. The homogenous modification of P3HT can promote separation of photogenerated electron–hole pairs on the TiO2 nanocrystalline thin film, which suppresses the recombination of photogenerated charge carriers, thus improving its photocatalytic activity.

Pb2+-doped (Sr1−xPbx)3Ti2O7 (SPT) ceramics were fabricated by a solid state reaction. The stability and lattice structure of Sr3Ti2O7 and Sr4Ti3O10 Ruddlesden–Popper (RP) phases were studied as a function of Pb2+ content and sintering atmosphere. X-ray diffraction indicates that SrO(SrTiO3)n RP phase formation is sensitive to the Sr:Ti ratio of the raw materials and is a complex circularly iterative process. When the PbO concentration is less than x = 0.03, pure Sr3Ti2O7 can be obtained. Sr4Ti3O10 was found to be the main phase in the SPT samples for x ≥ 0.075. Pb2+ stabilizes SrO(SrTiO3)n RP phases by substitution for Sr2+ which reduces the lattice stress of the RP phase. It was observed that SrO vaporization losses at high temperature can be compensated by the decomposition of the intermediate SrPbO3 phase at lower temperature.

The microstructural evolution during spark plasma sintering of ultrafine WC–1 wt% Si (n-WC–Si) is presented. At 1323 K (T < TmSi), extensive stacking faults on the $\left\{ {10\bar 10} \right\}$ prismatic planes are observed. The defect microstructure can be described as a combined shear of $1/6\left\langle {\bar 12\bar 13} \right\rangle$ on the prism planes and simultaneous out-diffusion of carbon through the faults to the interparticle boundaries. At temperatures near TmSi (1673 K), a large fraction of abnormally grown platelets is observed. These platelets contain a single planar defect on their basal planes, described by a ${1 \mathord{\left/ {\vphantom {1 3}} \right. \kern-\nulldelimiterspace} 3}\left\langle {10\bar 10} \right\rangle$ translation of the carbon atoms across a Σ1 grain boundary (GB). Three factors contribute to the abnormally high density of platelets: (i) the low-temperature prismatic dislocations interact to form facet-roughening steps/kinks that act as nucleation sites, (ii) a liquid phase triggers an increased growth rate in the vicinity of the Si inclusions, and (c) the basal twin produces a re-entrant edge for 2D nucleation.

A systematic analysis of effect of metallurgical defect and phase transition on geometric accuracy and wear resistance of iron-based parts fabricated by selective laser melting was conducted. By composition optimization of alloying elements, the desirable martensitic structure was directly obtained based on high-speed laser induction and the content of retained austenite was observed to be different under various laser parameters. Using an optimized scan speed of 1600 mm/s could lead to the highest densification level of 99.24% and the lowest content of retained austenite of 3.5%, hence acquiring a considerably high Rockwell hardness of 61.9 HRC, a reduced coefficient of friction of 0.40, and wear rate of 1.8 × 10−5 mm3/N m. A thorough investigation of dimension offset due to martensite transformation in conjunction with theoretical calculation was performed. Lower top surface roughness (5.25 μm) and reduced side roughness (13.84 μm) were achieved at the optimized scan speed of 1600 mm/s.

The effect of annealing treatment on the microstructures, mechanical, and wear properties of a CuZnAlMnSiNiCr brass alloy is investigated. The results indicate that nanosized Mn5Si3 particles are observed to precipitate from the β phase at temperatures above 750 °C. After annealing at 800 °C for 4 h, the formation of finely, coherent precipitates dispersed within the matrix results in the great improvement of strength, hardness and thus the high wear resistance, which can be proven by the decreased wear rates and friction coefficients. According to the examination of the wear topography, adhesive, abrasive, and oxidative wear are found to be the major wear forms during the dry sliding wear. After the precipitation-hardening treatment, the adhesion and abrasion decrease, and few spallings and cracks are observed on the worn surfaces. In addition, the wear behavior of the alloy is found to be strongly dependent on its strength and hardness.

Hot deformation behavior of Incoloye028 alloy was investigated by conducting hot compression tests on Gleeble-3800 simulator in the temperature range of 1223–1473 K and the strain rate range of 0.1–50 s−1. True stress–true strain curves showed that the flow stress increases with the decrease of deformation temperature and the increase of strain rate. The constitutive equations of Incoloy028 alloy were obtained by introducing Zener–Hollomom parameter, the flow behavior can be described by the hyperbolic sine function and the activation energy changes with strain rate and temperature significantly. The hot working maps of Incoloy028 alloy were proposed on basis of dynamic materials model. The hot working maps for different strains indicated that there were two instability zones, one zone is in the temperatures range of 1423–1473 K and strain rate range of 0.1–50 s−1, and another zone is in the temperature range of 1223–1423 K and strain rate range of 0.6–1 s−1. The reasonable hot working temperature range is 1423–1473 K when strain rate is more than 50 s−1.

X-ray diffraction analysis, transmission electron microscopy, and thermodynamic calculation were used to investigate the effect of microstructural condition of austenite on the microstructural characteristics of the nanoscale bainite ferrite in a high carbon steel. As austenization temperature increases to 950 °C, there are a higher vacancy concentration and homogenized distribution level of the interstitial carbon atom in the austenite grains. The movement of more di-vacancies combination could encourage the generation of the γ → α embryo nucleus. The interstitial carbon atoms have a stronger inhibitory effect on the formation of the γ → α embryo nucleus and homogenized distribution of the interstitial carbon atoms are able to make the inhibitory effect exist everywhere in the austenite grains. In consequence, the bainite ferrite could only nucleate in a smaller area (several nanometers), and grow into slender laths in a smaller width and a larger length.

Using first-principles calculations, the fundamental understanding of the structure, electronic, elastic, lattice dynamic, and optic properties of three Mg-based ternary chalcopyrite semiconductors have been analyzed in detail within density functional theory scheme. To ensure an accurate determination of our calculated results, we considered five popular generalized gradient approximation formulations such as Perdew and Wang, Perdew–Burke and Ernzerhof (PBE), revised PBE, modified PBE, and Armiento–Mattson 2005 as well as local-density approximation (LDA) for the exchange-correlation potentials. It is found that all the calculated values of band gap for these compounds are underestimated compared to existing studies, while LDA-based functional gives better results than others. The electronic band structure demonstrated that these compounds have direct band gap at the Γ point in the Brillouin zone. It is observed that these compounds are mechanically stable in the chalcopyrite structure.

Cross-weld hardness profile, notch-tensile strength, and impact toughness of T92 steel heat-affected zone (T92 HAZ) of dissimilar T92/TP316H welds were studied in dependence of their postweld heat treatment (PWHT) and subsequent long-term aging. Two weldments series were individually subjected to either “single-step” tempering PWHT or a modified “two-step” renormalizing and tempering PWHT. Subsequently, the welds were isothermally aged at 625 °C for durations from 500 up to 11,000 h. The “single-step” PWHT preserved sharp hardness gradient of T92 HAZ, whereas the “two-step” PWHT led to the hardness values equalization. The T92 HAZ of the weldment after the “two-step” PWHT exhibited initially lower strength and higher toughness, compared to the weldment after the “single-step” PWHT. However, after long-term aging a more suitable combination of T92 HAZ mechanical properties i.e., the higher toughness and acceptable strength exhibited the weldments processed by “single-step” PWHT.