High-purity niobium single crystals of five different orientations were compressed at 77 K to 2–4% plastic strain to investigate the mechanisms operative in the initial stage of yielding. The crystals deformed in the direction close to the [001] axis exhibit predominant slip on the high-stressed (101) and a much lower stressed $\left( {0\bar{1}1} \right)$ plane. The expected slip on the $\left( {\bar{1}01} \right)$ plane is nearly homogeneously distributed with only a few sharp slip traces corresponding to localized slip. The samples compressed along center-triangle orientations and those close to the $\left[ {011} \right] - \left[ {\bar{1}11} \right]$ edge deform predominantly by twinning on {112}〈111〉 systems with some contribution from slip on the $\left( {\bar{1}01} \right)\left[ {\bar{1}\bar{1}\bar{1}} \right]$ system with the highest Schmid factor. A majority of twins exhibit internal contrast due to alternating slip on $\left( {\bar{1}01} \right)$ and $\left( {0\bar{1}1} \right)$ planes. No slip traces are observed in the matrix adjacent to the twin, which implies that twin boundaries are impenetrable obstacles for the motion of dislocations.

Manganese sulfides (MnS) with a diversity of well-defined morphologies and phases have been successfully synthesized by the solvothermal approach. The phase structure and morphology of MnS could readily be tuned by adjusting the sulfur sources and solvents. Hollow γ-MnS spheres were obtained by treating L-cysteine and manganese source in ethylene glycol (EG) at 200 °C for 2 h, whereas a replacement of the mixture solvent by EG and deionized water yields the hierarchical flower-like γ-MnS. γ-MnS tubes were also produced under the same condition by using diethylene glycol and deionized water as solvents. When thioacetamide used as the sulfur source and oleylamine used as the solvent, monodisperse α-MnS nanoparticles with the mean diameter of 17 nm could be synthesized successfully. The phase structures, sizes, and morphologies of samples were investigated in detail by powder X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The UV-vis absorption peak and the width of band gap with different morphologies of the as-prepared MnS were measured. The samples described in this paper are promising to be utilized in solar cells, biomedicine, short wavelength electronic devices, photocatalysis, and other fields.

The layer-by-layer self-assembly technology was adopted to prepare a new generation of supercapacitor electrode material, GOQDs@NiAl-LDH, between Ni–Al layered double hydroxide (LDH) and graphene oxide quantum dots (GOQDs). First, Ni–Al LDH was prepared by coprecipitation of nickel nitrate and aluminum nitrate and then delaminated by ultrasonication. Second, NiAl-LDH was combined with GOQDs that were prepared by a ball milling reaction using hexachlorobenzene as raw material. The electrochemical data indicate that the composite (OGL9) exhibits highest specific capacitance, large current charge and discharge characteristics, and excellent cycle stability when the content of GOQDs is 10%. And the specific capacitance of composite reaches to 869 F/g at the current density of 1 A/g. Moreover, the capacitance retention at 1 A/g discharge current condition is 69.6% after 2000 cycles. And the results indicate that the OGL9 can be a promising electrode material for supercapacitor applications.

The aim of this study was to investigate the in vivo degradation mechanism and the mechanical properties of poly(lactide-co-glycolide)/beta-tricalcium phosphate (PLGA/β-TCP) composite anchors. Anchors composed of PLGA and β-TCP were implanted in the dorsal subcutaneous tissue of beagle dogs for 6, 12, 16, and 26 weeks. The degradation of the materials was evaluated by measuring the changes in thermal behavior, crystallinity, and mechanical properties. Scanning electron microscope (SEM) was used to observe the surface and longitudinal section of the material. The evaluation of mechanical strength retention and degradation properties suggest that the addition of β-TCP particles efficiently enhances their mechanical properties and thermal characteristics and delays their degradation rate. By analyzing the results of SEM, X-ray diffraction, and differential scanning calorimetry, we can infer that after 12 weeks, the connection between β-TCP and PLGA becomes less compact, which accelerates the decline of mechanical strength.

AZ31 magnesium alloy sheets were A-TIG-welded through a coating of flux, which contained different ratios of Ce powder and nano-sized SiC as reinforcement particles and equal mass of TiO2 as activating fluxes. The microscopic analysis results illustrated that relatively low content of Ce in the reinforcement particles caused the formation of Al3Ce precipitates and refined the grains of α-Mg phase together with β-Mg17Al12 and SiC particles. The increase in microhardness and ultimate tensile strength of the joints was 6.2% and 19.2%, respectively, when reinforcement particles contain 20 wt% Ce compared to the joints coated without Ce. By studying the electrochemical test results, when using 20 wt% Ce + 80 wt% SiC as reinforcement particles, the corrosion current density was the lowest and the corrosion resistance reached the largest value, reflecting the improvement of corrosion property of the joint affected by Ce element.

Carbon nanotubes (CNTs) were added to carbon nanofibers (CNFs) as additives to improve their electrochemical properties. In the present work, CNFs were prepared by using pressurized gyration with polyacrylonitrile as the precursor. The microstructure and electrochemical properties of samples were investigated by scanning electron microscopy and electrochemical workstation, respectively. The results showed that the network structure formed in the fiber, and the fiber diameter decreased with the increase of working pressure. The integral area of cyclic voltammetry curve reached the maximum and the charge/discharge time of constant current charge/discharge curve reached the longest in the case of the CNT concentration is 0.50 wt% and working pressure is 0.2 MPa. At the same time, it exhibited the best electrochemical performance with a specific capacitance of 79 F/g at a current density of 100 mA/g. Compared with the specific capacitance of pure CNFs, the specific capacitance of CNFs with the concentration of CNTs 0.50 wt% increased by about 40%.

Energy-savvy auto-combustion synthesis was used to form the porous BaLi2Ti6O14 titanate anode. It registered the lowest calcination temperature (800 °C) along with the shortest calcination duration (2 h). Rietveld analysis confirmed the purity of the orthorhombic (s.g. Cmca) product phase. The bond valence site energy analysis indicated a 1D ionic conduction along c axis with low activation energy and 2D pathways along (010) with high activation energy. AC conductivity analysis revealed a bulk conductivity of 2.41 × 10−4 S/cm (at 300 °C) with a moderate activation energy barrier (0.68 eV). From cyclic voltammetry, the Li+ diffusion coefficient was calculated to be 10−11–10−12 cm2/s. The as-synthesized BaLi2Ti6O14 reversibly intercalated ∼1.3 Li+ involving a 1.42 V Ti4+/Ti3+ redox activity delivering capacity ∼100 mA h/g with good cyclability over 100 cycles. Furthermore, BaLi2Ti6O14 was found to reversibly intercalate ∼0.89 Na+. With suitable diffusional and electrochemical performance, BaLi2Ti6O14 form a safe titanate anode for secondary batteries.

Formamidinium–tin–strontium halides (CH(NH2)2Sn1−ySryX3 (FASnX3), X = I, Br and 0.0 ≤ y ≤ 0.1) were investigated. X-ray diffraction analysis revealed orthorhombic FASnI3 (space group Amm2) and SnI2 for X = I as well as cubic FASnBr3 (space group $Pm\bar{3}m$) and SnBr2 for X = Br, respectively. For X = I, the optical spectra displayed a decrease of the absorption edges with increasing Sr content (1055 nm, y = 0.0; 950–960 nm, y > 0.0) and a direct semiconducting behavior with narrow band energy gaps (1.31–1.34 eV). For X = Br, on increasing the absorption edges (492 nm, y = 0.0; 975 nm, y = 0.075), a direct semiconducting behavior with band energy gaps between 2.65 eV (y = 0.0) and 1.38 eV (y = 0.075) were observed and the emission photoluminescence (PL) spectra (excitation wavelength λexc = 380 nm) showed an increase of the luminescence response after the thermal treatment.

AlMg alloys have widespread industrial applications. Grain refinement techniques have been frequently used to achieve high strength in these alloys. Here, we report on the fabrication of epitaxial co-sputtered AlMg thin films with high-density growth twins. The microstructure evolution with varying Mg composition has been characterized. Nanoindentation and in-situ micropillar compression tests show that the strength of AlMg alloys increases with increasing Mg composition. The flow stress of epitaxial nanotwinned Al–10 at.% Mg thin film exceeds 800 MPa. The modified Hall–Petch plots incorporating the solid solution strengthening effect suggest that, compared to high angle grain boundaries, incoherent twin boundaries are equivalent barriers to the transmission of dislocations in nanotwinned AlMg alloys.

Synthesis of ZIF with zinc, cobalt, or copper was carried out by microwaves. The effect of metal center on morphologies and pores of products was studied. Nitrogen adsorption/desorption onto ZIFs was examined by density functional theory. The micro, meso, and macropores of ZIF-8, Zn/Co-ZIF-8, and Cu/ZIF-8 ranged 99.814–99.969%, 0.055–0%, and 0.031–0.130%, respectively. Average pore sizes of ZIF-8, Zn/Co-ZIF-8, and Cu/ZIF-8 are 1.291, 1.194, and 1.164 nm, respectively. Monolayer saturation limits of nitrogen onto ZIF-8, Zn/Co-ZIF-8, and Cu/ZIF-8 were 21.152, 18.943, and 17.784 mmol/g, respectively. Further, the results included densities, total surface areas, total pore volumes, and average particle sizes of ZIF-8, Zn/Co-ZIF-8, and Cu/ZIF-8.

Transient transmission oscillations in X-cut and Z-cut congruent, iron-doped, and magnesium-doped lithium niobate samples were measured using 50 fs, 800 nm, 0.5 nJ pulses from a self-mode-locked Ti:sapphire laser in an optical pump–probe system. Several Raman-active oscillation modes excited by these pulses were observed as changes in the transmitted probe intensity versus time delay between the pump and probe pulses. The samples were rotated to determine how the incident polarization of the pump pulses affects the mode excitations. The observed Raman-active oscillations correspond to previously reported symmetry modes measured with traditional, continuous-wave, Raman spectroscopy using the same scattering geometry. In addition, a polariton mode and other, previously unreported, lower-frequency modes were observed in each of the samples. The transmission intensity data for each sample were fit successfully to a superposition of sinusoidal functions with exponentially decaying amplitudes.

The immobilization of cytochrome c (cyt c) on tea polyphenol functionalized and reduced graphene oxide (TPG) was carried out by a simple adsorption process. Intriguingly, TPG with large surface area exhibited excellent adsorption behaviors and good biocompatibility. The adsorbed materials were characterized by various methods including scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). And the effects of adsorption behavior of cyt c were discussed in detail. The results showed the adsorption behavior was dependent on the pH value and showed a high adsorption capacity as high as 1.414 × 104 mg/g and was friendly to normal cells (mouse fibroblast cell line, L929). In conclusion, we proposed the introduction of TPG as novel material and used the adsorption method to immobilize cyt c, which would provide a novel material and simple method for the enrichment of protein.

The formation of low-angle grain boundaries (LABs) in the rejoined platforms of a Ni-based single crystal superalloy under different directional solidification rates was investigated by the experimental investigation and the ProCAST simulation. The results showed that the growth morphology and orientation evolution of dendrites in the platforms were different under the withdrawal rates in the range of 60–100 μm/s and then resulted in different types of LABs. At lower withdrawal rates, the longitudinal LABs were common in the rejoined platforms. Both the sliver defects and the orientation deviation of original primary dendrites from two independent growth paths could cause the longitudinal LABs in the platforms. At higher withdrawal rates, the dendrite growth patterns were more complex and the secondary branches with lateral growth tended to deviate from their original orientation, eventually leading to the formation of some transverse LABs. Finally, some suggestions to prevent the formation of different LABs are provided.

The 2Cr13/316L multilayered composite plates were fabricated by hot rolling with recycle heating step. The effect of rolling reductions on microstructure and properties was investigated. The 2Cr13 layer consists of martensite and lath ferrite, but the middle layer has less ferrite than both sides. The content and grains of ferrite increase with the increase of the reduction and number of reheating, which leads to a decrease in the hardness of the 2Cr13 layer. The hardness of the 2Cr13 layer is determined by the volume ratio of martensite and ferrite. Tensile strength of the specimens with the rolling reduction of 72% and 82% reached 815.8 MPa and 763.4 MPa, while elongations were 20% and 20.8%, respectively. With the increase of the rolling reduction, the fracture mode also changed from cleavage fracture to dimple fracture. There were no cracks and delamination when the 2Cr13/316L composite plate bent to 130° and 180°, which indicated better interfacial bonding.

Two different sized As(0) nanoparticles As1 (50 ± 7 nm) and As2 (70 ± 10 nm) are prepared by reducing arsenite with NaBH4 in the pH range 7–9, at controlled temperature (10 and 40 °C). Further, galvanic replacement reaction is used exploiting the reducing nature of As(0) to prepare two different sized hollow gold nanoparticles (HGNPs) AuNP1 (55 ± 7 nm) and AuNP2 (72 ± 7 nm). These HGNPs exhibit high catalytic activity towards 4-nitrophenol reduction under various conditions following first-order kinetics. AuNP1 shows ~6.6 time higher turnover frequency compared with that of AuNP2 due to its smaller size. Both catalysts are recycle able.

Theoretical investigations on ferroelectric tunnel junctions (FTJs) with asymmetric electrodes and a composite barrier are presented. A large tunneling electroresistance effect exists for the Pt/SrTiO3/BaTiO3/SrRuO3 junction; on the other hand, exchange of the dielectric and ferroelectric layer stacking sequence can seriously degrade the performance. These correlations are rationalized by the proposed concept of an asymmetry factor, defined as the ratio between the average barrier heights of FTJs for two opposite polarization orientations. We show that a large asymmetry factor is beneficial to FTJs. This work may provide a way to enhance the performance of FTJs by structure engineering.

In the present work, the TiB2-reinforced AA6061 composites were successfully in situ synthesized by laser surface alloying using a mixture of Ti and AlB2 powders. The microstructure evolution and properties of the composites were systematically studied. The results showed that TiB2 particles displayed a homogeneous distribution in the aluminum matrix with controllable contents and morphologies. By adjusting the molar ratio of alloying powders, phase constitution of the composites was varied. Thermodynamic calculation was used to analyze the phase selection during the solidification. It was found that the morphology of TiB2 particles was converted from hexagonal plate into rod-like structure with an increase of Ti contents. Transmission electron microscopy results illustrated that the in situ synthesized TiB2 particles exhibited a well-bonded interface with the Al matrix. Properties characterization revealed a significant enhancement in microhardness and abrasion resistance compared with the aluminum substrate attributed to the presence of the TiB2 reinforcements. The strengthening and wear mechanism were also discussed.

In certain alloy systems, a liquid of a fixed composition freezes to form a mixture of two solid phases, one of which may be faceted and the other nonfaceted (i.e., a ‘degenerate’ or irregular eutectic). The role of trace metallic additions on the microstructure of the eutectic has received significant research interest over the last half-century, culminating in advances in theoretical, computational, and experimental fronts. The drastic morphological, topological, and crystallographic changes that accompany metallic additions strongly influence the mechanical properties of the as-synthesized eutectic microstructure. In this review, we survey the mechanistic origins leading to a modified eutectic microstructure and describe the current status in the field of eutectic solidification in the presence of metallic modifying agents. We will also discuss the remaining challenges and future opportunities that would help move the field forward and enable bottom–up tuning of the complex degenerate microstructures to technological demands.

SnO2 aerogels were successfully synthesized by using SnCl4, ammonium hydroxide (AH), formamide, propylene oxide, and tetraethoxysilane as tin source, reaction promoter, drying control chemical additive (DCCA), gel accelerator, and surface modifier, respectively, via the sol–gel method, combined with subsequent ambient pressure drying of sol–gel. The results of Fourier transform infrared spectroscopy proved that the CH3CH2OSi-bond was transferred to SnO2 gel. A contact angle measuring instrument was utilized for the study of hydrophicity and hydrophobicity of SnO2 aerogels, and the complete porous skeleton structure of SnO2 aerogels was confirmed by field emission scanning electron microscopy (FESEM) and nitrogen adsorption–desorption analyzer, denoting AH allowed SnO2 aerogels to shape more macropores. Based on the thermal resistance tester, it showed that the SnO2 aerogels had low thermal conductivity. The biggest specific surface area and lowest thermal conductivity of SnO2 aerogels were 447.26 m2/g and 0.0717 K/(m•K), respectively.

Because of rapid solidification involved in the laser or e-beam based additive manufacturing (AM) process, solution treatable metallic parts made by these methods usually possess a unique nonequilibrium microstructure which changes significantly during subsequent thermal treatment. Such evolution alters the size, morphology, length scale, and distribution of microstructural features and has a substantial impact on thermal properties and possibly on electrical properties as well. This study focuses on effects of microstructural evolution on thermal properties of an additively manufactured AlSi10Mg part. The changes of thermal properties such as thermal expansion, heat capacity, thermal diffusivity, and thermal conductivity as a function of thermal treatment are reported. The results show that the formation of supersaturated primary α aluminum and unique cellular structure imparted by fast solidification in the AM process are the major cause for the low thermal diffusivity and low thermal conductivity observed in this solution treatable, as-built part. A correlation between microstructural evolution and changes in thermal properties is established. Advantages and tailoring of the thermal properties of additively built parts are discussed. Implications of these results are important for other additively manufactured components based on popular solution treatable alloys.