Formation of Y3Al5O12–Al2O3 eutectic microstructure with off-eutectic composition

Homogeneous-eutectic microstructure of Y₃Al₅O₁₂–Al₂O₃ system without coarse primary crystals was formed at an off-eutectic composition. This method utilizes a low migration rate in an amorphous phase. A mixture of Y₂O₃ and Al₂O₃ having the off-eutectic composition was melted and quenched rapidly to form an amorphous phase. A heat-treatment of the amorphous phase at 1000 °C and 1300 °C for 30 min formed Y₃Al₅O₁₂ and Al₂O₃ phases. SEM observation of this material, which was formed from the amorphous phase at 1300 °C for 30 min, showed homogeneous eutectic-like microstructure. The formation of the primary crystals (coarse Al₂O₃), which are always observed in the off-eutectic compositions by ordinary method, was completely suppressed.     

Synthesis of Nitrogen-doped Titania by Solvothermal Reactions in Alcohols

Nitrogen-doped titania nanoparticles were obtained by the homogeneous precipitation in hexamethylenetetramine- titanium trichloride-alcohol aqueous solutions at 90℃ followed by heating at 190℃. Anatase, rutile and brookite were obtained, where the crystallite size, specific surface area and color greatly changed as 5~50 nm, 20~200 m2/g and light gray to yellow, depending on the solvent and pH. The products after calcination were yellow, indicating doping with nitrogen ion. All colored titania showed photocatalytic activity under visible light irradiation for the oxidative decomposition of nitrogen monoxide in air. Especially, the nanoparticles of anatase type nitrogen-doped titania obtained using methanol aqueous solution showed excellent photocatalytic activity.     

Biochemical and molecular biological analyses of space-flown nematodes in Japan, the first international caenorhabditis elegans experiment (ICE-First)

The first International Caenorhabditis elegans Experiment (ICE-First) was carried out using a Russian Soyuz spacecraft from April 19–30, 2004. This experiment was apart of the program of the DELTA (Dutch Expedition for Life science Technology and Atmospheric research) mission, and the space agencies that participate in the International Space Station (ISS) program formed international research teams. A Japanese research team that conducted by Japan aerospace Exploration Agency (JAXA) investigated the following aspects of the organism: (1) whether meiotic chromosomal dynamics and apoptosis in the germ cells were normal under microgravity conditions, (2) the effect of the space flight on muscle cell development, and (3) the effect of the space flight on protein aggregation. In this article, we summarize the results of these biochemical and molecular biological analyses.     

Thin-film polycrystalline silicon solar cells formed by flash lamp annealing of a-Si films

We have fabricated thin-film solar cells using polycrystalline silicon (poly-Si) films formed by flash lamp annealing (FLA) of 4.5-µm-thick amorphous Si (a-Si) films deposited on Cr-coated glass substrates. High-pressure water-vapor annealing (HPWVA) is effective to improve the minority carrier lifetime of poly-Si films up to 10 µs long. Diode and solar cell characteristics can be seen only in the solar cells formed using poly-Si films after HPWVA, indicating the need for defect termination. The actual solar cell operation demonstrated indicates feasibility of using poly-Si films formed through FLA on glass substrates as a thin-film solar cell material.     

11 T liquid helium-free superconducting magnet

An 11 T liquid helium-free superconducting magnet designed at 6 K in vacuum using high temperature superconducting current leads was developed. The coil was conductively cooled down from room temperature to 4.1 K in 40 h by two 4 K GM-cryocoolers. In a performance test, the coil temperature rose to 6.8 K for the inner Nb₃Sn coil and 5.9 K for the outer NbTi coil, while sweeping the field at 5 A min⁻¹. A central field of 10.7 T in a 52 mm room temperature bore was generated at an operating current of 149 A. Holding the field at 10.5 T was achieved continuously for 24 h at a constant coil temperature of 4.8 K.     

Critical Parameters and Critical-Region ($$p,\rho,T)$$ Data of trans-1,1,1,3-Tetrafluorobut-2-ene [HFO-1354mzy(E)]

This study presents the experimental measurement of the \(p\rho T\) properties and critical parameters of a low GWP type refrigerant, trans-1,1,1,3-Tetrafluorobut-2-ene (HFO-1354mzy(E)). The sample purity of the substance was 99 area %. \(p \rho T\) property measurements and visual observations of the meniscus of HFO-1354mzy(E) were carried out using a metal-bellows volumometer with an optical cell. The critical temperature was determined by observation of the critical opalescence. The critical pressure and critical density were determined as the inflection point of the isothermal \(p \rho T\) property data at the critical temperature. For more precise clarification of the thermodynamic surface in the vicinity of the critical point, additional \(p \rho T\) property measurements were carried out on three isotherms in the supercritical region. The expanded uncertainties (\(k = 2\)) in the temperature, pressure, and density measurements were estimated to be less than 3 mK, 1.2 kPa, and 0.32 \(\hbox {kg} \cdot \hbox {m}^{-3}\), respectively. The expanded uncertainties of the critical parameters were estimated to be less than 13 mK, 1.4 kPa, and 2.3 \(\hbox {kg} \cdot \hbox {m}^{-3}\), respectively. These values are the first reported for HFO-1354mzy(E) and are necessary for the development of its equation of state in the near future.     

Carbazole–Dibenzofuran Dyads as Metal‐Free Single‐Component White‐Color Photoemitters

White‐color light emitters from single organic molecule without heavy metals are valuable for practical applications in organic light‐emitting devices. In this study, carbazole (Cz)–dibenzofuran (DBF) donor–acceptor dyads are designed for white‐color light emitters. Originally, these molecules show photoluminescence (PL) in near ultraviolet region. However, upon successive ultraviolet (UV) irradiation, white‐color PL appears, comprising dual‐color phosphorescence from the amorphous and crystalline state of the dyad. A continuous UV irradiation makes the twisting angle between the Cz and DBF planes flatten through the triplet‐excited state, which proceeds crystallization. Thermal annealing and UV irradiation can switch the blue‐ and white‐color phosphorescences from the dyad. Furthermore, charge injection generates white‐color electroluminescence. The materials with PL color modulation ability by UV‐light irradiation and heating can be applicable as light‐ and thermo‐sensors.