Preparation and Characterization of Ti(2)O(3) Films Deposited on Sapphire Substrate by Activated Reactive Evaporation Method

(001)-oriented Ti(2)O(3) films were epitaxially grown on a(001)-face of sapphire single-crystalline substrate by an activated reactive evaporation method. The formation ranges of stoichiometric and nonstoichiometric Ti(2)O(3) films were determined as a function of the substrate temperature (Ts), the oxygen pressure (Po(2)) and the deposition rate. Stoichiometric Ti(2)O(3) films were grown at Ts≧673K under Po(2)≧1.0×10(-4)Torr, which showed the metal-insulator transition with a sharp change in electrical resistivity from 3.5×10(-2) to 2.6×10(-3)Ωcm at 361K. Nonstoichiometric films prepared under less oxidized conditions did not exhibit the transition. The nonstoichiometry of the Ti(2)O(3)films was discussed in terms of excess Ti ions

Phylogenetic analyses of Japanese golden chanterelles and a new species description, Cantharellus anzutake sp nov.

ArticleMycoscience. 59(2): 153-165. (2018)journal articl

Bezier Simplex Fitting: Describing Pareto Fronts of Simplicial Problems with Small Samples in Multi-objective Optimization

Multi-objective optimization problems require simultaneously optimizing two or more objective functions. Many studies have reported that the solution set of an M-objective optimization problem often forms an (M-1)-dimensional topological simplex (a curved line for M=2, a curved triangle for M=3, a curved tetrahedron for M=4, etc.). Since the dimensionality of the solution set increases as the number of objectives grows, an exponentially large sample size is needed to cover the solution set. To reduce the required sample size, this paper proposes a Bezier simplex model and its fitting algorithm. These techniques can exploit the simplex structure of the solution set and decompose a high-dimensional surface fitting task into a sequence of low-dimensional ones. An approximation theorem of Bezier simplices is proven. Numerical experiments with synthetic and real-world optimization problems demonstrate that the proposed method achieves an accurate approximation of high-dimensional solution sets with small samples. In practice, such an approximation will be conducted in the post-optimization process and enable a better trade-off analysis.Comment: To appear in AAAI 201

Efficient establishment of pure cultures of yellow chanterelle Cantharellus anzutake from ectomycorrhizal root tips, and morphological characteristics of ectomycorrhizae and cultured mycelium

ArticleMycoscience. 60(1): 45-53. (2019)journal articl

Bioactivity of Nb(V) and Ta(V)-Doped Calcium Silicate Glasses

Nb(2)O(5)-and Ta(2)O(5)-doped calcium si1icate glasses were soaked for various periods in a simulated body fluid(Kokubo solution) up to 30 days. Apatite formation ability of the surface of these glasses were investigated with thin-film X-ray diffraction and FT-IR reflection spectroscopy. The effects of these additive oxides on the bioactivity of CaO･SiO(2) based glass were discussed. A small amount of Nb(2)O(5) and Ta(2)O(5) suppressed the rate of silica hydrogel layer formation and the apatite formation on the surface of the glasses. The rate of the apatite nucleation on the surface of Nb(2)O(5)-doped calcium silicate glass was slower than that on the surface of Ta(2)O(5)-doped calcium silicate glass. It was concluded that the decrease in the apatite forming ability of calcium silicate glasses by these additive oxides is attributed to the suppression of formation of silica hydrogel layer which plays an important role in apatite nucleation

Preparation and Characterization of Ti 2 0 3 Films Deposited on Sapphire Substrate by Activated Reactive Evaporation Method

SYNOPSIS (OOl)-oriented TiP3 films were epitaxially grown on a (OOl)-face of sapphire single-crystalline substrate by an activated reactive evaporation method. The formation ranges of stoichiometric and nonstoichiometric Ti 2 0 3 films were determined as a function of the substrate temperature (Ts), the oxygen pressure (P0 2 ) and the deposition rate. Stoichiometric Ti 2 0 3 films were grown at Ts6 73K under P02~1.0x1Q-4Torr. which showed the metal-insulator transition with a sharp change in electrical resistivity from 3.5x 10-2 to 2.6 xlO-3 .Qcm at 361K. Nonstoichiometric films prepared under less oxidized conditions did not exhibit the transition. The nonstoichiometry of the Ti 2 0 3 films was discussed in terms of excess Ti ions. IN'IRODUCTION The crystal structure of titanium sesquioxide (TiP3) can be described as a corundum-type structure. The metal-insulator transition in Ti 2 0 3 is a very unique and well-known phenomenon. The intrinsic electrical properties of this oxide causes the transition. I - 3 ) The bulky single-crystal of TiP3 grown by a Czochralski method exhibits the transition at 435K with a sharp decrease in electrical resistivity from 9xlO-3 to3xlO-4 .Qcm on increasing temperature. 4 ) Although Ti 2 0 3 thin films are expected to be useful in a practical view point such as an application to the thermistor in the electric devices, there are few investigations of preparation and physical properties of Ti 2 0 3 thin films. In general. the electrical properties of thin films are sensitive to morphological, crystallographic and chemical properties such as shape. grain size. orientation and stoichiometry of films. These properties depend upon preparation method as well as preparation conditions

Ancient DNA reveals multiple origins and migration waves of extinct Japanese brown bear lineages.

Little is known about how mammalian biogeography on islands was affected by sea-level fluctuations. In the Japanese Archipelago, brown bears (Ursus arctos) currently inhabit only Hokkaido, the northern island, but Pleistocene fossils indicate a past distribution throughout Honshu, Japan's largest island. However, the difficulty of recovering ancient DNA from fossils in temperate East Asia has limited our understanding of their evolutionary history. Here, we analysed mitochondrial DNA from a 32 500-year-old brown bear fossil from Honshu. Our results show that this individual belonged to a previously unknown lineage that split approximately 160 Ka from its sister lineage, the southern Hokkaido clade. This divergence time and fossil record suggest that brown bears migrated from the Eurasian continent to Honshu at least twice; the first population was an early-diverging lineage (greater than 340 Ka), and the second migrated via Hokkaido after approximately 160 Ka, during the ice age. Thus, glacial-age sea-level falls might have facilitated migrations of large mammals more frequently than previously thought, which may have had a substantial impact on ecosystem dynamics in these isolated islands