The frequency response of a 37 MHz bulk LiNbO3 surface acoustic wave (SAW) filter with a 200-nm-thick ZnO overlayer exhibited a downshift in the frequency with ultraviolet (UV) light due to acoustoelectric interactions between the photo-generated carriers in the semiconducting ZnO and the surface acoustic waves. In contrast, a 36 MHz ZnO thin film SAW delay-line with insulating ZnO films exhibited an upshift in the frequency. The response was more pronounced at higher harmonics (130–315 MHz) and was attributed to changes in the elastic/dielectric properties in the upper surface layer of ZnO. A linear change in the frequency with UV intensity shows immense applicability for wireless ultraviolet sensor applications.

Mesostructured lamellar lead sulfide has been synthesized for the first time at room temperature in acidic media, employing sodium dodecyl sulfonate (SDS) as template and soluble lead salts, and hydrated sodium sulfide as the inorganic sources. The material was chiefly characterized by x-ray powder diffraction, high-resolution transmission electron microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy, and thermogravimetric analysis. In the material, the Pb:S molar ratio for the inorganic phase is about 1:1.2, with a distance of about 2.7 nm between the inorganic layers.

Lithium manganese oxide powders (LiMn2O4) with a spinel structure were synthesized via an optimized water-in-oil emulsion process. The influence of the emulsification conditions on the microstructures and physicochemical properties of LiMn2O4 powders was investigated. The phase purity of the synthesized powders significantly depends on the water-to-oil volume ratio in the emulsion. Increasing the water-to-oil ratio tends to decrease the stability of the emulsion that in turn leads to a segregation of water and oil phases. The unstable emulsion system results in the formation of an impure phase—Li2MnO3—that markedly decreases the charge and discharge capacities of the cathode materials. When water/oil volume ratio equals 1/5 or 1/10, monophasic spinel powders are formed at temperatures as low as 400 °C. In addition, decreasing the concentration of the aqueous phase substantially reduces the particle size of LiMn2O4 powders. Nanometered-LiMn2O4 powders with a particle size of 50 nm are obtained when the concentration of the aqueous phase is 1.0 M and the water-to-oil volume ratio is 1/5. Decreasing the particle size of LiMn2O4 powders was demonstrated to effectively increase the specific capacity and improve the cyclability of LiMn2O4 powders.

The synthesis of BaSn(OH)6 acicular crystals by precipitation at 100 °C from aqueous solutions and their transformation in the perovskitelike compound BaSnO3 was investigated. Single acicular crystals 100–200 μm in length were obtained from a 0.05M solution, whereas bundlelike aggregates of 20–40 μm were precipitated from 0.2–0.6 M solutions. The x-ray diffraction pattern of barium hexahydroxostannate was indexed according to monoclinic symmetry with cell parameters a = 11.029 ± 0.002 Å, b = 6.340 ± 0.001 Å, c = 10.563 ± 0.001 Å = 128.51 ± 0.01°, α = γ = 90°. The BaSn(OH)6 particles decomposed to BaSnO3 and water at approximately 270 °C and the original morphology was retained. The resulting product had specific surface area up to 30–40 m2/g and consisted of 10–20 nm crystallites. The larger unit cell edge in comparison to the reference value and the continuous weight loss up to 1200 °C indicate that water is not completely released during decomposition and a substantial amount of proton defects (up to 0.4 mol per mole of BaSnO3) is incorporated in the perovskite lattice as OH− groups. Normal crystallographic properties of BaSnO3 are restored only after calcination at 1300 °C.

Electron microscopy observations of α–ZrP whiskers with the NaCl structure, grown by chemical vapor deposition at 1300 °C, showed that there exists a hexagonal structure region (a = 0.369 nm and c = 1.248 nm) near the surface of the whiskers. High-resolution lattice image observations revealed that the method of stacking the eight-layered hexagonal structure is different from the reported hexagonal β–ZrP. In addition to the eight-layered structure, 12-layered and 16-layered structures were also observed, indicating a variety of ZrP polymorphisms.

TiO2 nanocrystalline powder was synthesized by homogeneous precipitation method using urea, and its characteristics were investigated through comparison with the powder prepared by conventional precipitation using ammonia. The homogeneously precipitated powder was anatase-type TiO2 with a particle size of 4–5 nm and a uniform spherical particle shape. The fact that the transformation from anatase to rutile was prohibited at elevated temperatures in the homogeneously precipitated powder can be useful to prepare anatase-type TiO2 thin films by calcination at high temperatures. With increasing heat-treatment temperature, the particle size of the homogeneously precipitated powder was smaller than that of the conventionally precipitated powder, and the particle shape was more uniform. The homogeneously precipitated powder showed good photocatalytic activity for Ag ion photoadsorption because the powder had both good crystallinity and a large specific surface area of 280 m2/g.

Lead zirconate titanate Pb(Zr0.52Ti0.48)O3 (PZT) thin films were grown on Pt/Ti/Si(001) by metal organic decomposition (MOD). The effects of the annealing procedure on the crystalline microstructure, hysteresis loops, and fracture toughness of PZT thin films were investigated by x-ray diffraction, RT66A analyzer, and Vickers indentation method, respectively. It was found that the fracture toughness, crystalline microstructure, and ferroelectric properties depend on the annealing procedure. When the annealing temperature is in the range of 600–750 °C, the higher the annealing temperature, the better the crystalline quality. The fracture pattern diagram, as a function of indentation load and annealing temperature, was introduced to describe the fracture characteristics of PZT thin film induced by indentation load. With the increase of annealing temperature from 600 °C to 750 °C, the fracture toughness of PZT thin films decreased from 0.492 MPa m1/2 to 0.478 MPa m1/2.

The growth of tin whiskers formed on sputtered tin layers deposited on brass was studied using electron microscopy. The occurrence of whiskers appeared to be largely independent of the macroscopic stress state in the film; rather it was microscopic compressive stresses arising from the formation of an intermetallic phase that appeared to be the necessary precursor. Whisker morphology was a result of whether nucleation had occurred on single grains or on multiple grains. In the latter case, the whiskers had a fluted or striated surface. The formation of whiskers on electron transparent samples was demonstrated. These samples showed the whiskers were monocrystalline and defect free, and that the growth direction could be determined.

Sol-gel materials of TiO2 and vanadium-modified TiO2 of nominal composition 4, 8, and 16 wt.% vanadium were prepared by evaporation of aqueous colloidal sols obtained by the hydrolysis of aqueous solutions of titanium(IV) chloride with the appropriate amount of vanadyl oxalate using aqueous ammonia followed by peptization of the resulting hydrated solids using nitric acid. The nature of the sol-gel materials and their behavior on calcinations at temperatures up to 1273 K were investigated using x-ray fluorescence, powder x-ray diffraction, transmission electron microscopy, and electron diffraction and FT-Raman spectroscopy. At 333 K, all the gels comprised small (about 5 ± 1 nm) particles of anatase together with traces of brookite. The particle size changed little on thermal treatment at 573 K, but increased significantly at higher temperatures and was accompanied by transformation to rutile. Incorporation of vanadium in the gels reduced the temperature at which rutile began to appear from 923 K in pure TiO2 to 773 K in the V/TiO2 gels. Only rutile was present at high temperatures, except for the 16 V/TiO2 gel, when small amounts of phase-separated vanadia were also observed. A 2–3% substitutional incorporation of V4+ ions in the tetragonal rutile lattice occurred at high temperatures, but the majority of the vanadium was present in an amorphous, highly dispersed fashion.

Uniformly distributed nanoparticles created by heating carbon nanotubes synthesized by arc-discharge were studied by electron diffraction, high-resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), and x-ray energy dispersive spectrometer (EDS). The nanoparticles have diameters in the range of 3–15 nm. Electron diffraction pattern and HRTEM images analysis both show that the nanoparticles can be nickel or diamond. EELS and EDS analysis in a dedicated scanning transmission electron microscope showed that the nanoparticles are face-centered-cubic nickel particles rather than diamond nanocrystals. The mechanism of formation of nickel nanoparticles below its melting point is discussed.

A phase of new bichromatic (green, red) phosphor Ca2Al3O6F:Eu(III), was found to grow in a small fraction along with Ca5(PO4)3F:Eu(III) phase if aluminum is previously added to the reaction mixture of the latter and flourish to a sizable concentration on subsequent heat treatment. The luminescence spectrum of the as-prepared sample, where Ca5(PO4)3F:Eu(III) is the dominant phase, shows a strong band at 612 nm along with a series of less intense bands at 573, 584, 644, and 692 nm due to different 5D0 → 7FJ (J = 0, 1, 2, 3, 4) transitions and indicates that the presence of aluminum in the system forces the Eu(III) ions to occupy exclusively one type of site rather than multiple types of sites. As the aluminate phase grows, a strong green emission band around 520 nm due to the 5D2 → 7F3 transition of Eu(III) occurs concomitant with a splitting of almost all the 5D0 → 7FJ bands. The excitation spectrum of the green emission (520 nm) shows a strong absorption band at 393 nm, and the electron spin resonance spectrum of this material shows existence of a fluorine-related hole center of (F2n)− type in the matrix. It is argued that the (F2n)− holes are localized in the interstitial of the Ca2Al3O6F phase near the calcium-substituted Eu(III) ions to maintain the charge balance and form a complex with the latter, which plays a vital role in the process of green emission.

We report on long-lasting phosphorescence and photostimulated long-lasting phosphorescence phenomena in femtosecond laser-irradiated Mn2+-doped alumino-phosphofluoride glasses. Long-lasting phosphorescence was observed in the glass samples after the irradiation of the focused femtosecond laser. Photostimulated long-lasting phosphorescence was observed in the femtosecond laser pre-irradiated region by excitation of an ultraviolet light of 365 nm, after the femtosecond laser-induced long-lasting phosphorescence decayed completely. The mechanisms of these phenomena have been discussed. These phenomena have potential uses in three-dimensional ultra-high-density optical recording.

TlGa1−xSbxS2 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) single crystals were grown using the Bridgman–Stockbarger method. The direct energy gaps of the single crystals were found to be 2.586, 2.459, 2.344, 2.228, 2.119, and 1.987 eV for the composition x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0, respectively, at 20 K. The indirect energy gaps were found to be 2.479, 2.357, 2.232, 2.118, 1.983, and 1.871 eV for the composition x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0, respectively, at 20 K. The optical energy gaps decreased linearly with increasing composition x. The temperature dependence of the optical energy gaps for each of the single crystals was well fitted with the Varshni equation.

The microstructures of thick plasma-sprayed yttria-stabilized zirconia (8% mass fraction yttria) deposits were studied in a series of Porod small-angle neutron scattering (SANS) and multiple small-angle neutron scattering (MSANS) experiments. Three main void components were identified in the deposits: intrasplat cracks, interlamellar planar pores, and globular pores. The SANS and MSANS measurements were analyzed using the traditional theory for Porod scattering and a recently developed three-component model for MSANS evaluation. The average size, volume fraction, internal surface area, and orientation distribution for each void component within the deposits were determined. This study focused on gaining a better understanding of the effects of initial feedstock particle size and annealing temperatures on the microstructure of deposits sprayed under equivalent particle-impact conditions. Quantitative results are presented for each of four deposit samples: one prepared using the as-received feedstock particle wide-size distribution and three prepared from feedstock powder of different and relatively narrow particle size ranges with average sizes of 32, 47, and 88 μm. Except for the coarse (88 μm) feedstock powder, only mild monotonic variations were found in the microstructural anisotropies, the porosities (13 ± 1%), and the internal surface areas in the as-sprayed deposits. The internal surface area was independent of the feedstock particle size, even with the coarse feedstock. When the deposits were annealed at high temperatures (1100 and 1400 °C), the microstructures were altered with a reduction of the total internal surface area and a mild coarsening of the voids. These changes in the microstructural evolution were well-captured and described by the three-component model. The results were compared and related with those obtained from scanning electron microscopy images and elastic moduli measurements.

In this paper, the improvement of casting properties of the high-strength AlZnMgCu alloys is described. This improvement was achieved by additions of Ni, Mg, and Si, which formed eutectic phases, thus reducing the crystallization interval of the alloy. The comparison of the castability and hot-tearing tendency was made for three alloys: nearly single-phase AlZn6Mg2 alloy, quasi-ternary eutectic AlZn7Mg7Cu1Ni3Si3 alloy, and common casting AlSi10 alloy. It was shown that the castability and hot-tearing tendency of the quasi-ternary eutectic alloy are similar to those of the AlSi alloy.

This paper aims at establishing a number of electrons/atom (e/a)-based criterion for searching bulk metallic glasses (BMGs) and quasicrystals with large forming abilities in the Zr-based multicomponent alloy systems. After discussions on the diffraction characteristics corresponding to the Fermi surfaces-Brillouin zone interaction in the Zr-based Hume-Rothery phases, the Hume-Rothery matching rule is well explained when the effective e/a value of the matrix element Zr is taken as 1.5. The BMG- and quasicrystal-related phases are pointed out to be a family of nearly e/a-constant phases in a given alloy system. An e/a-constant criterion is then used to predict the ideal composition of the quasicrystals and BMGs in the Zr-Ti-Ni, Zr-Al-Ni, and Zr-Al-Ni-Cu systems, respectively. Nearly pure bulk Zr-Ti-Ni quasicrystals and a series of BMGs with glass-forming abilities greater than that of the known Zr65Al7.5Ni10Cu17.5 alloy are found.

The effects of dilution of tetraethyl orthosilicate (TEOS) with ethanol on the shape and monodispersity of silica particles were investigated. The results indicated that the dilution of TEOS with ethanol can depress the formation of new nuclei and the aggregation or adhesion of particles and make the distillation of TEOS unnecessary to achieve monodispersed silica spheres. A seeded growth technique using continuous drop addition of TEOS diluted with 4× volume of ethanol was developed to improve monodispersity and spheric shape and increase the size of silica particles. The monodisperse silica particles (150 nm ± 5%−1.2 μm ± 1%) with fine spheric shape were successfully synthesized by the seeded growth technique. Using the homemade 280 nm ± 2.8% silica spheres, we prepared opals of high quality which showed periodically ordered packing and a photonic band-gap effect.

Nano-TiO2 modified composites, including TiO2 + EP648 and M40/TiO2 + EP648, were fabricated, in which the nano-TiO2 particles were dispersed in an EP648 epoxy matrix using a high-speed shearing emulsification technique. A jet type of vacuum ultraviolet (VUV) source was used to simulate the VUV spectrum in space and acquire various doses of VUV irradiation. In terms of the changes in specific-area mass loss and surface morphology, the resistance to VUV irradiation of the TiO2 + EP648 and M40/TiO2 + EP648 nanocomposites was evaluated. Experimental results showed that compared to the EP648 epoxy and M40/EP648 composite, the specific-area mass loss of the TiO2 + EP648 was decreased by 44% and that of M40/TiO2 + EP648 composite by 38%, respectively. By increasing the dose of VUV irradiation, the internal layer shear strength of the M40/TiO2 + EP648 increased gradually, while that of the M40/EP648 showed a decreasing trend. After irradiation, the surface of the M40/TiO2 + EP648 changed a little, but that of the M40/EP648 was damaged severely. It was indicated by means of scanning electron microscopy and atomic force microscopy observations that the VUV damage occurred mainly in the epoxy matrix, while the carbon fibers showed good resistance to irradiation.

Strontium-modified lead titanate thin films with composition Pb1−xSrxTiO3 were grown on Pt/Ti/SiO2/Si substrates using the polymeric precursor method. The structural phase evolution as a function of the Sr contents was studied using micro-Raman scattering, specular reflectance infrared Fourier transform spectroscopy, and x-ray diffraction. The results showed a gradual change from tetragonal to cubic structure, the transition occurring at about x = 0.58. The infrared reflectance spectra showed that the frequency of several peaks decreases as the strontium concentration increases. These features are correlated with a decrease in the tetragonal distortion of the TiO6 octahedra as the strontium concentration increases.

A eutectic point in Pr-rich Pr-(Cu,Ni)-Al alloys was experimentally determined by measuring the solidus temperature (Tm) and liquidus temperature (T1). It was found that Pr68(Cu0.5Ni0.5)25Al7 (at.%) is at the eutectic composition in the pseudoternary Pr–(Cu0.5Ni0.5)–Al alloys. The alloy Pr68(Cu0.5Ni0.5)25Al7 exhibits better glass-forming ability (GFA) than the ternary eutectic alloy Pr68Cu25Al7. However, the best GFA was obtained at an off-eutectic composition (Pr54[Cu0.5Ni0.5]30Al16) in the Pr–(Cu0.5Ni0.5)–Al alloys, which can be formed in fully amorphous rods with diameter of 1.5 mm by copper mold casting. Moreover, the glass-transition temperature Tg increases quickly (from 367 to 522 K) with the increasing of the Al content (from 3 to 27 at.%). The deviation of the best GFA composition from the eutectic point [Pr68(Cu0.5Ni0.5)25Al7] was explained in terms of the asymmetric coupled eutectic zone, the competition between growth of crystalline phase and formation of amorphous, and the higher glass-transition temperature Tg on the hypereutectic side.