The formation of a composite gel fiber from cellulose acetate and zirconium tetra-n-butoxide was examined. The gel was thought to have formed by the coordination of OH and CO groups of cellulose to zirconium, taking six coordination numbers around the zirconium. The gel fiber had good stability in common solvents, phosphate solution, and electrolyte solution. Then, under mild conditions, a β-galactosidase was entrap-immobilized on it. The apparent Michaelis constant of the Immobilized β-galactosidase was larger than that of native β-galactosidase, whereas the opposite tendency was observed for the maximum reaction velocity. The activity of the immobilized β-galactosidase increased as the fiber diameter decreased. These findings indicated that lactose hydrolysis took place in the vicinity of the fiber surface. The immobilized β-galactosidase had a higher thermal stability than the native type.

Superconducting Yba2Cu3O7−δ (YBCO) films with critical transition temperature Tc(0) of 90 K were fabricated via a fluorine-free, metal trimethylacetate based sol-gel route. Precursor films were spin-coated onto single-crystal (001) LaAlO3 (LAO) and (001) SrTiO3 (STO) substrates. Optimization of the burnout process resulted in films with excellent out-of-plane and in-plane texture. Transport critical current densities, Jc, of 1.6 and 1.1 MA/cm2 were obtained at 77 K in self-field on films grown on LAO and STO substrates, respectively. This is the first demonstration of high-Jc YBCO film fabrication using a fluorine-free, ex-situ process.

The crystallinity dependence of the microwave dielectric losses in (Ba,Sr)TiO3 thin films was investigated. The sputter-deposition temperatures were altered to vary the level of thin-film crystallinity on a Pt/Si substrate. The dielectric losses (tan δ) were measured up to 6 GHz without parasitic (stray) effects by using a circular-patch capacitor geometry and an equivalent-circuit model. The microwave dielectric losses increased from 0.0024 ± 0.0018 to 0.0102 ± 0.0017 with increasing crystallinity. These deteriorated dielectric losses showed a good correlation with the symmetry-breaking defects, as confirmed by Raman spectra at approximately 760 cm−1, inducing microscopic polar regions above the Curie temperature of the bulk (Ba0.43Sr0.57)TiO3.

Titania fibers were synthesized by a liquid mix process, starting by complexing titanium isopropoxide with a chelating agent solution to form a precursor resin for further fiber drawing. The as-drawn continuous precursor fibers underwent a weight change of 80% and a volume change of 75% after heat treatment at 800 °C in nitrogen followed by an additional treatment at 600 °C in air. The fibers consisted mainly of rutile with 5–10% anatase. Further treatment at 700 °C transformed the anatase completely into rutile. Fibers with finished diameter less than about 15 μm were solid with smooth surfaces. Fibers with finished diameter greater than about 15 μm were hollow and spirally cracked in a uniform manner. Fibers treated at 600 °C showed no visible grains. Additional annealing at 800 °C grew grains to an average size of 0.3–0.4 μm. The fibers appeared solid and dense.

The heat-treatment retention time effect of carbonized polyvinylidenechloride (PVDC) was investigated. Homogeneous PVDC with a crystallite size of 267 Å was used as a precursor material for an electric double-layer capacitor electrode. The P-120m material, which was heat treated for 120 min at 700 °C, shows a larger specific capacitance than any other material in this study. It shows the largest values reported up to now, reaching values as high as 100.2 F/g for a two-electrode system, which is equivalent to 400.8 F/g in a conventional three-compartment electrode system. It is difficult to distinguish the difference in the pore-size distribution by way of gas adsorption as the retention time is varied. However, the difference can be clarified using a novel method based on the analysis of transmission electron microscopy images. As the retention time for heat treatment increases, the pore size grows through the coalescence of small pores. Furthermore, a new concept for the electric double-layer capacitance is suggested on the basis of analysis of the transmission electron microscopy observations.

Polarization of deformation twinning (its propagation in a certain sense but not in the opposite one) is taken for granted. However, the same phenomenon can occur for a superdislocation glide as well, as is demonstrated in this paper. The consequences for plastic deformation of polysynthetically twinned TiAl crystals with the lamellar interfaces parallel to the loading direction are discussed. It is not the interface itself that is an obstacle for propagating deformation but also the fact that a deformation mode with the parallel Burgers vector cannot be activated in the neighboring lamella due to the directionality of superdislocation motion leading to additional stress increase.

Novel photochromic nanocomposite thin films were prepared by entrapping polyoxometalate in a polyacrylamide matrix via the ultrasound technique. The ultrasound irradiation has a great effect on the microstructure and photochromic properties of the hybrid films. The polyoxometalate nanoparticles are finely dispersed in the polymer matrix after ultrasound treatment, instead of agglomeration in the unirradiated film with ultrasound. Consequently, the photochromic behaviors of the hybrid films can be controlled from irreversible heteropolybrown to reversible heteropolyblue by ultrasound. The influence of ultrasound on microstructure and photochromic properties is due to the sonochemical controlling interfacial interactions in the hybrid system.

ZnO nanowires with diameters of 40–200 nm were grown with a gold catalyst in bulk quantities on alumina substrates and sapphire substrates. This synthesis procedure was achieved by heating a 1:1 mixture of ZnO and Zn powder to 500 °C with trace water vapor as an oxidizer. X-ray diffraction and transmission electron microscopy revealed that the nanowires were in the pure wurtzite phase. Photoluminescence spectroscopy showed two peaks: one was a strong ultraviolet emission at around 380 nm, which corresponds to the near-band-edge emission; the other was a weak near-infrared emission around 750 nm, which indicates a low concentration of oxygen vacancy. Moreover, we observed that the Zn/Au alloy droplets appeared on the tips of ZnO nanowires. As a consequence, we can select areas to grow ZnO nanowires by patterning the thin metal film on the substrates. These findings prove that the low-temperature growth mechanism is via vapor–liquid–solid rather than vapor transport deposition or vapor supersaturation (vapor–solid) mechanism. On the basis of the site-specific growth and the low-temperature requirement developed from this work, the synthesis of ZnO is compatible to microelectric machining system processing.

This paper presents the results of a nanoindentation study of the effects of strain gradient plasticity on the elastic–plastic deformation of lithographie, galvanoformung, abformung (LIGA) Ni microelectromechanical systems (MEMS) structures plated from sulfamate baths. Both Berkovich and North Star/cube corner indenter tips were used in the study to investigate possible effects of residual indentation depth on the hardness of LIGA Ni MEMS structures between the micro- and nanoscales. A microstructural length scale parameter, , was determined for LIGA nickel films. This is shown to be consistent with a stretch gradient length-scale parameter, ls, of approximately 0.9 μm.

The photocatalytic properties of TiO2 rutile powder with acicular primary particles were characterized using the photocatalytic reaction in aqueous 4-chlorophenol (4CP) solution and compared to those of TiO2 anatase with almost the same surface area of approximately 200 m2g. The characteristics of commercial P-25 TiO2 powders with the surface area of approximately 55 m2/g were also compared to rutile and anatase powders. The rutile phase powders surpassed both anatase and P-25 ones in decomposition rate for 4CP. The excellent photo-oxidative ability of the powder was dependent on the specific powder-preparation method, which led to a direct crystallization in aqueous solution, regardless of the crystalline structures of the powders.

The optical absorption spectra of cobalt-doped MgIn2S4, CdIn2S4, and HgIn2S4 single crystals grown by a chemical transport reaction were investigated at 7 K. The values of Dq and B calculated from the observed spectra show that the d electrons are more delocalized in the order of MgIn2S4, CdIn2S4, and HgIn2S4. Because this order corresponds to the decreasing order of the electronegativity differences between the metal and sulfur atoms of the host crystals, we conclude that as the metal-sulfur bonds in the host crystals are more covalent, the d electrons of the cobalt impurities are more spread out and the cobalt-sulfur bonds are also more covalent.

Poly(ethylene glycol) (PEG) additives with different molecular weights were used to modify sol-gel precursor solutions for preparing lead zirconate titanate (PZT) thin films. The morphology, crystalline structure, and mechanical and electrical properties of the films were characterized. The relationship between the characteristics of the films and the molecular weight of PEG was investigated. It was observed that the PEG eliminated cracking of the films during multiple pyrolysis treatments. However, with the increase of the PEG molecular weight, the films became less dense, which led to decreased Young's modulus and dielectric constant and increased coercive field. Our experiments showed that films prepared from sols modified by PEG with a molecular weight of 200 exhibited a dense morphology and excellent mechanical and electric properties without cracking.