Yellow-emitting long afterglow phosphors Sr3−xSiO5, xMF2: Eu2+, Dy3+ (0 ≤ x ≤ 0.15, M: Ba, Sr, Ca) have been prepared by high-temperature solid-state reaction method followed with rapid cooling process. Photoluminescence measurement reveals that the main emission of the phosphors locates at 575 nm, corresponding to the 4f65d1–4f7 transition of Eu2+. The introduction of alkaline earth metal fluoride effectively enhances the luminescence intensity and prolongs the afterglow time. Especially, the afterglow of the Sr2.95SiO5, 0.05BaF2: Eu2+, Dy3+ phosphor can last for 12 h. Thermal luminescence measurement shows that the trap density of Sr3SiO5: Eu2+, Dy3+ phosphor can be adjusted by adding different alkaline earth metal fluorides, which offers a feasible way to improve the afterglow properties of silicate phosphors.

LiMn2O4 nanowires have been synthesized by a two-step approach. γ-MnOOH nanowires are firstly synthesized by hydrothermal method and after further sintering with LiOH at 750 °C for about 3 h, the wire-like LiMn2O4 can be obtained. The structure of the final product is characterized by x-ray diffraction using Rietveld refinement. Its electrochemical performance is investigated by galvanostatic tests. The as-prepared LiMn2O4 nanowires display excellent cyclability. The LiMn2O4 nanowires with good cycle stability may be beneficial from the structural stability of LiMn2O4 crystal cell and one-dimensional nanostructure.

Single and multilayer diamond films were grown on silicon by varying substrate distance in hot-filament chemical vapor deposition. The grown films were characterized by scanning electron microscope (SEM) and Raman spectroscopy. From SEM surface images, it was observed that the films grown at substrate distances of 8, 7, and 6 mm and temperatures of 740, 780, and 830 °C possessed cauliflower, pseudocubes, and finally well-faceted cubes morphology. SEM fracture cross-sectional investigations revealed that growth of pseudocubes initiated on the top of cauliflower structure. By using the parametric relations gathered from single layer diamond growth studies, first time, multilayer diamond coatings were grown in situ with tunable thickness by only varying the substrate distance from filament assembly during deposition.

The Fe64B22.8Nd6.6Y3.9Nb2.7 nanocomposite permanent magnets in the form of rods of 2 mm in diameter and 25 mm in length have been prepared by annealing the amorphous precursors. The phase evolution, microstructure, and magnetic properties of Fe64B22.8Nd6.6Y3.9Nb2.7 nanocomposite permanent magnets have been investigated by x-ray diffractometry, transmission electron microscopy, and magnetometry techniques. The exchange coupling between the magnetically soft and hard magnetic phase is evidenced by the δM curves. The hard magnetic properties of the nanocomposites were found to be sensitive to the annealing process. The microstructure of the annealed nanocomposite consists of magnetically soft α-Fe (15–25 nm) and Fe3B (25–35 nm) grains and hard magnetic Nd2Fe14B (45–55 nm) grains. The optimum hard magnetic properties, such as jHc = 961.6 kA/m (12.0 kOe), Br = 0.65 T (6.5 kG), and BHmax = 65.17 kJ/m3 (8.19 MGOe), were obtained by annealing the alloy at 700 °C for 15 min and are related to the more refined nanostructure leading to strong exchange coupling between the soft and hard magnetic grains. Annealing above 700 °C induces a decoupling effect due to the coarsening of soft and hard magnetic phases.

In this study, Au/aminosilica composite nanospheres have been synthesized via a simple one-pot route using HAuCl4 and N-(3-trimethoxysilylpropyl)-ethylenediamine as starting materials. Scanning electron microscopy results show that these spheres are with diameters of about 300 nm. The obtained Au/aminosilica nanospheres were used as nonviral carriers for gene delivery. Compared with commercial Lipofectamine 2000, the Au/aminosilica nanospheres are with higher transfection efficiency and lower cytotoxicity. Furthermore, the nanospheres are biocompatible, which may find applications in gene delivery and drug carrier.

Two kinds of type-II heterostructures (HSs) of ZnO (wurtzite)/ZnSe (wurtzite) [ZnO (WZ)/ZnSe (WZ)] and ZnO (wurtzite)/ZnSe (zinc blende) [ZnO (WZ)/ZnSe (ZB)] were designed for photovoltaic applications by first-principle calculations. The calculated effective bandgap of 1.51 eV for the ZnO (WZ)/ZnSe (WZ) HS is more favorable for solar cell applications compared to that of 1.69 eV for the ZnO (WZ)/ZnSe (ZB) HS. Furthermore, the electrons and holes are more effectively separated at the interface of ZnO (WZ)/ZnSe (WZ) HS due to the stronger misfit stress field. Finally, a strained ZB ZnSe layer was introduced to transport the separated holes from WZ ZnSe layer, and an optimal structure of ZnO (WZ)/ZnSe (WZ)/ZnSe (ZB) was proposed to realize a solar cell with near-infrared response.

Oxidation kinetics of copper nanowires (CuNWs) with diameter 25 ± 4 nm were studied. The dry powder of CuNWs before oxidation comprises 73.2 wt% Cu and 26.8 wt% Cu2O. The oxidation reaction can be divided into two stages at weight of 111.2%. Oxidized CuNWs after Stage 1 consist of Cu2O and CuO. Oxidized CuNWs after Stage 2 comprise CuO only. The activation energies for both stages are determined by Kissinger method and other five isoconversional methods: Flynn–Wall–Osawa, Starink, Kissinger–Akahira–Sunose, Boswell and Friedman differential methods. The isoconversional activation energies determined by Starink method are used to fit different master plots. The Johnson–Mehl–Avrami equation gives the best fit. Surface atoms are the sites for the random nucleation, and the crystallite strain in CuNWs is the driving force for the growth of nuclei during the oxidation process.

Nitrogen (N) and boron (B) codoped diamond-like carbon (DLC) films were prepared on silicon oxide substrates by RF magnetron sputtering to optimize the electrical conductivity and hardness of DLC film. The electrical conductivity and hardness of the N–B codoped DLC films were controlled simultaneously by varying N2 flow rate with fixed B target power and varying B target power with fixed N2flow rate. The electrical resistivity of the B-doped DLC films showed a cup-shaped relationship with B target power and a U-shaped relationship with the N–B codoped DLC film. However, hardness of the B-doped DLC films showed a decreasing behavior but it was maintained almost constant for the N–B codoped DLC film. These particular electrical and hardness behaviors of the N–B codoped DLC films could be explained by a neutralization effect of N and B codoping.

Two-dimensional (2D) disordered copper 1,3,5-tricarboxylate film on copper foil was first reported in this paper. In the x-ray powder diffraction pattern of the as-prepared film, there were only two diffraction peaks exist in d value of 6.60 and 3.32 Å, which were correspond to the (400) and (800) diffractions of bulk HKUST-1, respectively. And the d value of 6.60 Å in bulk HKUST-1 is very close to the thickness of one-layered Cu2+ plus one-layered C9H3O63− (6.59 Å). The structure of as-prepared film was proved to be 2D disordered copper 1,3,5-tricarboxylate film. The periodical stacking of Cu2+ and C9H3O63−is perpendicular to the substrate. There is no periodic structure within the layer. Scanning electron microscopy, transmission electron microscope (TEM), high-resolution transmission electron microscope, infrared, Raman, and x-ray photoelectron spectrometer supported this result. This kind of disorder probably also existed in the reported HKUST-1 film that shows strong (400) diffraction in x-ray diffraction (XRD) pattern. This result probably explains why (400) diffraction in XRD pattern of reported synthesized HKUST-1 film is anomalously strong. This strategy is simple. No seed, no pretreated solvothermal mother liquors, and no specific functionalization are required.

The oxidation behavior of Cu50Zr50 and Cu46Zr46Al8 glasses during continuous heating up to 1073 K has been investigated, with special emphasis on the oxidation resistance in the supercooled liquid (SCL) state. For Cu50Zr50, the oxide layer mostly consists of monoclinic ZrO2 (m-ZrO2), while for Cu46Zr46Al8, the oxide layer consists of two different layers: an outer layer consisting of tetragonal ZrO2 (t-ZrO2) + Al2O3 + metallic Cu (oxidation product from the SCL state of the glass matrix) and inner layer comprised of m-ZrO2 + metallic Cu islands (oxidation product from the crystallized matrix). Cu-enriched regions consisting of Cu51Zr14 (in Cu50Zr50) or AlCu2Zr + Cu70Zr15Al15 + Cu51Zr14 (in Cu46Zr46Al8) are present below the oxide layer. The present study shows that the addition of Al (8 at.%) in Cu50Zr50 results in a significant deterioration of the oxidation resistance in the SCL state since the solutionizing of Al in t-ZrO2 leads to a higher oxygen ion vacancy concentration, thus providing a higher activity of oxygen ions.

The structural and magnetic properties of the Al cosubstituted cubic spinel ferrite series MgAlxFe2−xO4 (x = 0.0, 0.4, 0.8, and 1.0) synthesized through a coprecipitation method were characterized by means of x-ray powder diffraction, infrared (IR) spectroscopy, transmission electron microscopy (TEM), differential thermal analyses, and vibrating sample magnetometer. Lattice constants determined from x-ray diffraction (XRD) measurements exhibit a decrease with increasing Al3+ ions in the ferrites system. The particle size using TEM was ∼33 nm for magnesium ferrite, which is in good agreement with values obtained by XRD method. The crystallization spinel formation for the parent ferrite MgFe2O4 using differential thermal analysis (DTA) technique was 454 °C. The two main bands observed in the IR spectra (tetrahedral and octahedral) were in the range (568–628 cm−1) and (431–460 cm−1), respectively. Magnetization curve shows the highest value for the sample with concentration x = 0.4.

The standing porous nanoplate-built ZnO hollow microspheres with micro/nanostructure are fabricated based on a modified hydrothermal strategy, using citrate as structural director, and subsequent annealing treatment. The hollow spheres are composed of the vertically standing and cross-linked single crystalline porous nanoplates with the exposed surface of nonpolar (100) planes. Experiments have revealed the structural evolution: the formation of amorphous spheres in the initial reaction stage, followed by surface crystallization and nanoplate outward growth accompanied by inward dissolution of the amorphous spheres. Citrate in the precursor solution plays a dominant role in the formation of such porous ZnO hollow spheres. A model is presented, based on citrate-induced amorphous sphere formation and kinetically controlled dissolution and crystal growth. The model describes the formation of the hollow spheres, thermodynamically and kinetically.

To enhance the reliability of Pb-free solders in high temperature and high humidity conditions, the minor alloying elements of Be and Co are investigated in terms of the growth of Sn whiskers and various properties of Sn-based Pb-free solders. Sn whisker growth is suppressed by adding up to 0.02 wt% Be to Sn-based solders. Adding Be and Co can effectively reduce the undercooling of Sn–1.0Ag–0.5Cu (wt%) solders. And the microstructures of Sn–1.0Ag–0.5Cu–0.02Be solders are similar to those of Sn–1.0Ag–0.5Cu. Furthermore, adding Co to solders increases the microhardness number as a result of the solid solution hardening. Adding Be causes no changes in the morphology or thickness of Cu6Sn5 at the Cu/OSP (organic solderability preservative) under bump metallurgy interface. However, the scallop-like Cu6Sn5 microstructure changes to a flat (Cu,Co)6Sn5 microstructure when 0.05 wt% of Co is added to Sn–1.0Ag–0.5Cu–0.02Be solders.

Supercritical fluid (SCF) N2 was used as a physical foaming agent to fabricate microcellular injection-molded poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)–poly(butylene adipate-co-terephthalate) (PBAT)–hyperbranched-polymer (HBP)–nanoclay (NC) bionanocomposites. The effects of incorporating HBP and NC on the morphological, mechanical, and thermal properties of both solid and microcellular PHBV–PBAT blends were studied. NC exhibited intercalated structures in solid components, but showed a mixture of exfoliated and intercalated structures in the corresponding microcellular nanocomposites. The addition of NC improved the thermal stability of the resulting nanocomposites. The addition of HBP and NC reduced the cell size and increased the cell density of microcellular components. The addition of HBP and NC enhanced the degree of crystallinity for both solid and microcellular components. Moreover, with the addition of HBP, the area under tan δ curve, specific fracture toughness, and strain-at-break of the PHBV-based nanocomposite increased significantly whereas the storage modulus, specific Young’s modulus, and specific tensile strength decreased.

ZnO:Al and Zn1-xMgxO:Al films have been deposited by magnetron sputtering from ceramic targets at substrate temperatures from room temperature to 500 °C. We studied the relation between the electronic transport and the structural properties as a function of the deposition temperature. Films with the lowest resistivity (7·10−4 Ω cm for ZnO:Al and 3.6·10−3 Ω cm for Zn1-xMgxO:Al) can be prepared for deposition temperatures around 300 °C. This optimum is accompanied by the highest carrier concentration and the highest Hall mobility. Changes in crystalline quality and free carrier concentration are explained as a result of a bombardment of the films by high energetic negative oxygen ions during growth and by phase segregation for higher deposition temperatures. The dependence of the Hall mobility on the carrier concentration can be explained by grain barrier scattering for n <≈ 5·1020 cm−3 and by ionized impurity scattering for n >≈ 5·1020 cm−3. From the fit of the μ(n) dependence for both materials a trap density at grain boundaries of Nt ≈ 2.3·1013 cm−2 was determined.

The effect of direct current (dc) substrate bias on the promotion of nanocrystallization in Si network has been studied, specifically within He-diluted SiH4 plasma in radio frequency (RF)-plasma-enhanced chemical vapor deposition. In view of organizing nanocrystallinity, controlled transmission of energy to the growing surface is needed and that is obtainable from metastable helium (He*) bombardment and, in particular, ionic helium (He+) bombardment under negative substrate bias. The structural morphology has been adequately regulated to a homogeneous network restraining from an exclusive columnar structure that is coherent to low-temperature growth. Notable improvements in the film quality in terms of enhanced crystallinity with low hydrogen content as well as reduced incubation volume, bulk void, and surface roughness have been demonstrated, even at low substrate temperature and low RF power. Use of appropriate dc substrate-bias has been identified as a supplementary parameter efficiently organizing the growth, making it more device-friendly.

In the analysis of instrumented indentation data, it is common practice to incorporate the combined moduli of the indenter (Ei) and the specimen (E) in the so-called reduced modulus (Er) to account for indenter deformation. Although indenter systems with rigid or elastic tips are considered as equivalent if Er is the same, the validity of this practice has been questioned over the years. The present work uses systematic finite element simulations to examine the role of the elastic deformation of the indenter tip in instrumented indentation measurements and the validity of the concept of the reduced modulus in conical and pyramidal (Berkovich) indentations. It is found that the apical angle increases as a result of the indenter deformation, which influences in the analysis of the results. Based upon the inaccuracies introduced by the reduced modulus approximation in the analysis of the unloading segment of instrumented indentation applied load (P)–penetration depth (δ) curves, a detailed examination is then conducted on the role of indenter deformation upon the dimensionless functions describing the loading stages of such curves. Consequences of the present results in the extraction of the uniaxial stress–strain characteristics of the indented material through such dimensional analyses are finally illustrated. It is found that large overestimations in the assessment of the strain hardening behavior result by neglecting tip compliance. Guidelines are given in the paper to reduce such overestimations.

The spontaneous whisker growth phenomenon was investigated by exposing Sn3Nd intermetallic compound (IMC) to different environments. In a humid environment, tin whiskers grew rapidly; the incubation time for whisker formation was only 0.75 h. However, no whiskers were formed when Sn3Nd IMC was exposed to dry argon for 33 days or dry oxygen (DO) for 7 days. In situ observation of whisker growth during room ambient (RA) exposure gave an average whisker growth rate of the Sn3Nd IMC of about 11 Å/s, which are 2–3 orders of magnitude faster than that previously reported for tin plating. Following whisker growth, a new hydroxide compound, Nd(OH)3, was found to have formed on the Sn3Nd. The results show that the presence of humidity in the exposure environment is necessary for whisker growth from Sn3Nd. Finally, the driving force for whisker growth is also discussed.

This article focuses on the use of spherical nanoindentation measurements to estimate the pressure of cavitation impacts and its statistical distribution. Indeed, nanoindentation techniques are supposed to represent an effective tool in this field due to the similarities between substrate deformation under liquid impact and indentation testing. First, nanoindentation experiments were used to extract the mechanical parameters of a Nickel–Aluminum–Bronze alloy; second, pitting tests were performed at different operating pressures, and the geometrical characteristics of the pits were measured; and finally, the spectra of impact pressure and loads responsible for material erosion were obtained by coupling the findings of indentation tests with the analysis of pitting tests. Results assessed the capability of the proposed methodology to quantify the hydrodynamic aggressiveness of the cavitating flow. This procedure, which assumes the material itself as a sensor that is able to detect the impact loads, could represent an alternative solution to pressure transducers in estimating the cavitation intensity.