Effect of Dopant Species on Tetragonal (t')-to-Monoclinic Phase Transformation of Arc-Melted ZrO2-RO,1.5 (R = Sm, Y, Er, and Sc) in Water at 200°C and 100 MPa Pressure

Arc-melted specimens of rare-earth-doped zirconia (ZrO₂- X mol% RO_1.5; X = 4–10 for R = Sm, Y, Er, and X = 4–18 for Sc) were hydrothermally treated at 200°C, 100 MPa to investigate the dependence of the tetragonal-to-monoclinic transformation on dopant species and its content. The volume fraction of monoclinic phase Vm ( t ) increased from Vm (0) to a certain saturated value Vm (ω), following [ Vm ( t ) − Vm (0)]/[ Vm ( t ) − Vm (ω)] = 1 − exp(− k·t ), where t is the annealing time at 200°C, 100 MPa. The transform-abilities, Vm (0), Vm (ω), and k decrease with increasing dopant content. The Vm (ω) decreased with an increase of ionic radius of dopants. The relation 0 < Vm (ω) < 1 suggests that apparent noncompositional inhomogeneity exists in the hydrothermally treated sample.     

An electron microscopic study of the processes of nerve regeneration after lyophilized nerve homografting

The objective of the present study was to investigate the role of the Schwann cell basal lamina in nerve regeneration. To achieve this goal, we observed the process of axonal regeneration within a lyophilized nerve graft, in which only the basal lamina of the Schwann cell persisted. Sciatic nerves were removed from rats and lyophilized to kill the Schwann cells and other components. These grafts were transplanted to rat sciatic nerve defects. The rats were then killed after lapses of time. We observed the processes of axonal regeneration using a transmission electron microscope. Regeneration of axons along the inner surface of the Schwann cell basal lamina was clearly seen. These results suggest that, if tubular basal laminae persist, Schwann cells are not always necessary, and axonal regeneration can be induced in the direction toward the basal lamina.     

Is technology becoming science?

Citation and referencing data from recent biotechnology patents and bioscience papers is used to show that the bibliometric properties in these two realms are quite similar. Specifically, it is shown that the time distribution of references from both patents and papers are similar, with peak citing at two to four years prior to publication or issue. This is shown to hold for patents citing patents, for papers citing papers, and for patents citing papers. Furthermore, it is shown that there is a very skewed distribution of cited material in both patents and papers, with a relatively small number of highly cited patents and papers, and a relatively large number of documents which are cited only once or twice, or not at all. Finally, it is shown that there is a substantial amount of citation from biotechnology patents to the central scientific literature. We conclude from this that science and technology are far more closely linked today than is normally perceived, and that, in fact, the division between leading edge biotechnology and modern bioscience has alsmot completely disappeared.     

Hierarchical Representations of 2D/3D Gray-Scale Images and Their 2D/3D Two-Way Conversion

This article proposes G-octree as an extension of G-quadtree to three dimensions. A G-octree reflects in its construction a hierarchy of gray-scale level value homogeneity, as well as a hierarchy of spatial resolution. The article also develops two-way G-quadtree/Goctree conversion procedures based on the algorithms for the binary case. These procedures provide an integrated processing environment for hierarchically represented 2D/3D gray.scale images. We demonstrate our approach with an application to the color coding of macro-autoradiography images taken from rat brains.     

Formation of diffusionlessly transformed tetragonal phases in rapid quenching of ZrO2-Y2O3 melts

ZrO₂ polycrystals, partially stabilized by 2 to 7 mol% Y₂O₃, were arc-melted and rapidly quenched using an arc-imaging furnace with a hammer-anvil unit. Some of the specimens were further annealed at 1700° C for 3 h in air. The phases and the microstructures of these ZrO₂-Y₂O₃ polycrystals were examined through X-ray diffraction and transmission electron microscopy. Special emphasis was placed upon the examination of the microstructure of the metastable tetragonal phase (t phase) which was formed by a diffusionless transformation of the high-temperature cubic phase. It was found that the t phase exhibits a twinned and mosaic structure made of alternating layers of twin-related variants. A comparison of the present experimental results with other related works has also been made.     

Development of middle size full in‐cell LCD module for PC with IGZO

We developed the world's first middle size full in‐cell LCD for PC with IGZO technology. We evaluated a new Gate driver In Panel structure with latch circuit and confirmed that there were no problems with display and touch panel performance. Furthermore, we did a feasibility study of higher display resolutions and larger size panels, which showed future possibilities.     

Fracture Toughness of High-Pressure-Sintered Diamond/Silicon Nitride Composites

Diamond particles were dispersed in silicon nitride, sintered at 6 GPa and 1600°C for 30 min, and heat-treated under vacuum at 1300°C to induce graphitization of the diamond. Improved fracture toughness values up to 7.5 MN/m³¹² were achieved for these composites. Stress-induced microcrack toughening is considered to be a plausible toughening mechanism. Comparisons with diamondlalumina ceramics were made.     

Effect of Heat Treatment on Fracture Toughness of Alumina-Diamond Composites Sintered at High Pressures

Alumina composites containing dispersed diamond particles were fabricated under very high pressure at a temperature where diamond is stable. Subsequent heat treatment in vacuum improves the toughness of the 5 vol% composite but not that of the 10 vol% composite. The heat treatment time was varied for both composites, and the influence of graphitization and morphology of the second-phase particles on toughness were studied.