Promoted Hydride Substitution in BaTiO Cubes.

We report the synthesis of perovskite oxyhydride BaTiOH cubes (100-300 nm) using the topochemical hydride reaction of the hydrothermally synthesized oxide. X-ray and neutron diffraction studies revealed that the anion (hydride/oxide) exchange is greatly improved, leading to a maximum hydride content of 0.7, which is higher than previously reported, while no reaction is seen for those with oleic acid on their surface.

Penternary Wurtzitic Nitrides LiZnGeGaN: Powder Synthesis, Crystal Structure, and Potentiality as a Solar-Active Photocatalyst.

We developed a new penternary wurtzitic nitride system LiZnGeGaN (0 ≤ ≤ 1) by hybridizing LiGeN and ZnGeGaN. Fairly stoichiometric fine powder samples were synthesized by the reduction-nitridation process at 900 °C. While the end member LiGeN possessed a relatively large band gap of 4.

A near dimensionally invariable high-capacity positive electrode material.

Delivering inherently stable lithium-ion batteries is a key challenge. Electrochemical lithium insertion and extraction often severely alters the electrode crystal chemistry, and this contributes to degradation with electrochemical cycling. Moreover, electrodes do not act in isolation, and this can be difficult to manage, especially in all-solid-state batteries.

Effect of isothermal holding time on hydrogen-induced structural transitions of WO.

Tungsten trioxide (WO3) has the ability to transform oxygen-deficient structures (WO3-x; 0 ≦ x ≦ 1) at high temperatures under hydrogen. Because the band gap of WO3-x depends on the amount of W5+ species resulting from oxygen vacancies, this material is expected to have unique applications. Herein, to elucidate the WO3 reduction mechanism, we investigated the crystallographic changes of monoclinic WO3 powder samples using X-ray and neutron diffraction measurements under different reduction conditions, namely, under hydrogen at 500 or 800 °C for isothermal holding times of 30 min or 22 h.

Stabilization of Size-Controlled BaTiO Nanocubes via Precise Solvothermal Crystal Growth and Their Anomalous Surface Compositional Reconstruction.

Crystal growth of barium titanate (BaTiO) using a wet chemical reaction was investigated at various temperatures. BaTiO nanoparticles were obtained at an energy-efficient temperature of 80 °C. However, BaTiO nanocubes with a preferred size and shape could be synthesized using a solvothermal method at 200 °C via a reaction involving titanium tetraisopropoxide [(CH)CHO]Ti for nucleation and fine titanium oxide (TiO) nanoparticles for crystal growth.

Exploring the capability of mayenite (12CaO·7AlO) as hydrogen storage material.

We utilized nanoporous mayenite (12CaO·7AlO), a cost-effective material, in the hydride state (H) to explore the possibility of its use for hydrogen storage and transportation. Hydrogen desorption occurs by a simple reaction of mayenite with water, and the nanocage structure transforms into a calcium aluminate hydrate. This reaction enables easy desorption of H ions trapped in the structure, which could allow the use of this material in future portable applications.

P2-type layered NaCrMgTiO for Na storage applications.

Na0.67Cr0.33Mg0.

Quaternary Wurtzitic Nitrides (1 - )ZnGeN-2GaN ( = 0.02, 0.05): Disorder-Induced Band-Gap Narrowing and Potentiality as a Solar-Active Photocatalyst.

We examined the ZnGeN-GaN solid-solution system (ZnGeGaN) in the unexplored compositional region of < 0.10 to reveal the transitional structural and optical properties caused by the introduction of Ga. Fairly stoichiometric fine powder specimens with compositions of = 0.

High-Brightness Red-Emitting Phosphor La(Si,Al)(O,N):Ce for Next-Generation Solid-State Light Sources.

A novel high-brightness red-emitting phosphor, La(Si,Al)(O,N):Ce (LSA), which can potentially be used as a laser-excited light source, is demonstrated. Laser-excited phosphor system has great potential for use as a white-light source, as it is orders of magnitude brighter than white LEDs. Although conventional yellow-green phosphors show excellent luminescent properties even under high-power laser excitation, red-emitting phosphors, which are essential to achieve a high color-rendering index and low color-temperature, show quantum efficiency quenching.

Tetragonality induced superconductivity in anti-ThCrSi-type REOBi (RE = rare earth) with Bi square nets.

We report a series of layered superconductors, anti-ThCrSi-type REOBi (RE = rare earth), composed of electrically conductive Bi square nets and magnetic insulating REO layers. Superconductivity was induced by separating the Bi square nets as a result of excess oxygen incorporation, irrespective of the presence of magnetic ordering in REO layers. Intriguingly, the transition temperature of all REOBi including nonmagnetic YOBi was approximately scaled by unit cell tetragonality (c/a), implying a key role in the relative separation of the Bi square nets to induce superconductivity.

Atomic ordering, magnetic properties, and electronic structure of MnCoGa Heusler alloy.

The magnetic properties and atomic arrangement of MnCoGa Heusler alloy were investigated experimentally and by theoretical calculations. The magnetic moment derived from spontaneous magnetization at 5 K was 2.06 μ /f.

A comparative study of LiCoO2 polymorphs: structural and electrochemical characterization of O2-, O3-, and O4-type phases.

O4-type LiCoO2 as a third polymorph of LiCoO2 is prepared by an ion-exchange method in aqueous media from OP4-[Li, Na]CoO2, which has an intergrowth structure of O3-LiCoO2 and P2-Na0.7CoO2. O4-type LiCoO2 is characterized by synchrotron X-ray diffraction, neutron diffraction, and X-ray absorption spectroscopy.

Structural parameters of Pr3MgNi14 during hydrogen absorption-desorption process.

Structural parameters of Pr(3)MgNi(14) after a cyclic hydrogen absorption-desorption process were investigated by X-ray diffraction. Pr(3)MgNi(14) consisted of two phases: 80% Gd(2)Co(7)-type structure and 20% PuNi(3)-type structure. The pressure-composition (P-C) isotherm of Pr(3)MgNi(14) indicates a maximum hydrogen capacity of 1.

Layered hydride CaNiGeH with a ZrCuSiAs-type structure: crystal structure, chemical bonding, and magnetism induced by Mn doping.

Stimulated by the discovery of the iron oxypnictide superconductor with ZrCuSiAs-type structure in 2008, extensive exploration of its isostructural and isoelectronic compounds has started. These compounds, including oxides, fluorides, and hydrides, can all be simply recognized as valence compounds for which the octet rule is valid. We report herein the first example of a ZrCuSiAs-type hydride, CaNiGeH, which violates the octet rule.

Synthesis of new compound Gd5Ni19 with a superlattice structure and hydrogen absorption properties.

We successfully synthesized the new intermetallic compound Gd(5)Ni(19) and determined its crystal structure by X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM). The structure is a Sm(5)Co(19)-type superlattice structure (2H, space group P6(3)/mmc), and the lattice parameters were determined as a = 0.4950(1) nm and c = 3.

Synthesis and crystal structure of a Pr5Ni19 superlattice alloy and its hydrogen absorption-desorption property.

The intermetallic compound Pr(5)Ni(19), which is not shown in the Pr-Ni binary phase diagram, was synthesized, and the crystal structure was investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Two superlattice reflections with the Sm(5)Co(19)-type structure (002 and 004) and the Pr(5)Co(19)-type structure (003 and 006) were observed in the 2θ region between 2° and 15° in the XRD pattern using Cu Kα radiation. Rietveld refinement provided the goodness-of-fit parameter S = 6.

The comparison between cool and warm-hot environments on lipolytic response during prolonged exercise.

The purpose of this study was to investigate the effect of cool exposure on lipolytic response during prolonged intermediate-intensity exercise in humans. Eight male subjects participated in this study; they performed 120-min cycle ergometer exercise at 60% of maximal oxygen uptake (VO2max) in a climatic chamber at 10 degrees C (C) and 30 degrees C (WH). There were no significant differences in oxygen uptake and respiratory exchange ratio between the two conditions during the prolonged exercise.