Search

Rapid quenching of fused mixtures of nitride compounds at very high pressures yields glasses formed on the Li(sub 3)N-Ca(sub 3)N(sub 2)-P(sub 3)N(sub 5) system. Physical properties such as refractive index and hardness of oxide glasses is increased by the addition of nitrides. The addition of ionic nitrides enhances the physical properties.

The morphology and ontogeny of the postcranial skeleton were studied in three developmental series and a number of postmeta-morphic specimens of American shad, equaling more than 180 specimens. Specimens were cleared and stained with alcian blue to identify cartilage structures and with alizarin red to examine bone development. Histological preparations were made to confirm several questionable cases of endochondrial ossification. Pre-hatch embryos lack postcranial skeletal elements although the finfolds and pectoral fin buds are present. By the end of the yolk-sac larval period the hypurals in the caudal fin begin to form, rapidly followed by the development of the dorsal and anal fins. As the medial fins form, the elements of the vertebral column develop. The paired pelvic fins are the last to form during the metamorphic change of larvae into juveniles. The developmental sequence was divided into a series of stages that will allow future comparisons with other closely related species. Our results also show that 1) the uroneurals in shad are endochondrial in origin like other teleosts, 2) hypural 1 is autogenous because of incomplete ossification, 3) mineralization of protocentra occurs in an anterior to posterior direction resulting in chordacentra, and 4) development of the skull and anterior vertebral column exhibit several modifications associated with the otophysic system and sound transmission.

Ferroelectric BaTiO3 is widely used in capacitors, but the low Curie temperature limits a further use of BaTiO3. In this work we present an aqueous chemical solution deposition (CSD) route for BaTiO3 thin films, demonstrating that organic solvents are not required for CSD. Textured BaTiO3 thin films were deposited on SrTiO3 substrates. The in-plane dielectric properties were investigated using interdigitated electrodes and ferroelectric switching was observed up to 160±5 °C. The increased Curie temperature is proposed to result from thermal strain due to a mismatch in thermal expansion coefficient between the film and the substrate, and is in good agreement with the theory of strain engineering in BaTiO3. Finally, the decomposition and crystallization of BaTiO3 during thermal treatment were determined by the combination of thermal analysis, IR spectroscopy and X-ray diffraction of powder prepared from the solution. [ABSTRACT FROM AUTHOR]

The effect of Mo-substitution was investigated for the LaCoxNiyMozO3 system, obtaining single-phase perovskite for Mo-substitutions up to 20 at%. The crystal structure of the perovskite changed from rhombohedral, orthorhombic to monoclinic with increasing Mo-content. The thermal expansion was suppressed by Mo-substitution, while the electrical conductivity was also suppressed, but remained relatively high. [ABSTRACT FROM AUTHOR]

The effect of Mo-substitution was investigated for the LaCoxNiyMozO3 system, obtaining single-phase perovskite for Mo-substitutions up to 20 at%. The crystal structure of the perovskite changed from rhombohedral, orthorhombic to monoclinic with increasing Mo-content. The thermal expansion was suppressed by Mo-substitution, while the electrical conductivity was also suppressed, but remained relatively high. [ABSTRACT FROM AUTHOR]