Ammonia production using iron nitride and water as hydrogen source under mild temperature and pressure

Ammonia generation was studied in the reaction between water and nitrogen-containing iron at 323 K and atmospheric pressure. Similar to metallic Fe, the interstitial compound Fe₃N reduced water through Fe oxidation to produce hydrogen gas, while the N combined with atomic hydrogen to produce ammonia as a byproduct. The addition of carbon dioxide to this system accelerated the reaction with concomitant consumption of carbon dioxide. The promoted ammonia production upon addition of carbon dioxide can be attributed to the generation of atomic hydrogen from the redox reaction of carbonic acid and Fe, as well as removal of used Fe from the reaction system through the formation of a soluble carbonato complex. When carbonate was added to the reaction system, the production rates of ammonia and hydrogen increased further. The results here confirmed that ammonia can be synthesized from iron nitride under mild conditions by utilizing carbon dioxide.     

Photocatalytic Property and Electronic Structure of Lanthanide-based Oxysulfides

Lanthanide-based oxysulfides and sulfide, LnTaO_3.5S_0.5, Ln₁₀OS₁₄ (Ln = La, Pr, Nd, Sm) and La₄In₅S₁₃, were successively synthesized by sulfurization in a flowing H₂S. The sulfurization decreased the band-gap energies from >4 eV to <3eV, because of the formation of occupied S3p orbitals on the top of valence band. In accordance with the small band gap, the H₂ evolution from a 0.01 M Na₂S and 0.01 M Na₂SO₃ solution system was observed under irradiation of light up to >500 nm. The rate of H₂ evolution under light irradiation of >500 nm increased in the order of Ni/LaTaO_3.5S_0.5 < Ru/La₁₀OS₁₄ < Pt/La₄In₅S₁₃.     

Clinical and serological study of tsutsugamushi disease in northern Osumi, Kagoshima Prefecture

We report 34 cases of tsutsugamushi disease seen from 1989 to 1993 at Yagi Clinic, northern Osumi, Kagoshima Prefecture. Nineteen patients (55.9%) showed the highest antibody titers against the Kawasaki strain Orientia tsutsugamushi (Ot) and 13 (38.2%) against the Kuroki strain Ot. It is suggested that two antigenic types (Kawasaki and Kuroki) of Ot were distributed in Kagoshima Prefecture, and the Kawasaki type Ot more or less dominates Kuroki type Ot. There was no difference in clinical features between the two groups of patients.     

Onchocerca suzukii n. sp. and O. skrjabini (= O. tarsicola) from a relict bovid, Capricornis crispus, in Japan

The species from the tendons and sub-cutaneous tissue of the tarsal and carpal joints is identified as O. skrjabini Rukhlyadev, 1964 (this taxon, which was poorly defined and badly restored, is used instead of O. tarsicola to avoid dispute). O. skrjabini belongs to on homogeneous group of four species parasitic in Palearctic cervids, which seems to have evolved relatively recently. The morphological characteristics of the parasite of Capricornis are not sufficient to warrant the creation of a new taxon. The species from the subcutaneous tissue of the body is named O. suzukii n. sp. It belongs to a group comprising three species, parasites of antilocaprids and cervids from the Holarctic region and tropical domestic bovines, which seem to have evolved before the skrjabini group. The Japanese species does not present the hypertelic characters of the other species of the group. The microfilaria of O. suzukii is unknown. Thus it is not possible to say if this species is the same as one found in bovines (and, perhaps, in humans) in the Oita region of Kyushu Island.     

Channelling studies on the lattice location of B atoms in graphite

In order to obtain information on the lattice location of B atoms in graphite, channelling experiments have been performed at room temperature with a proton beam of an energy of 0.65-0.77 MeV for the 〈0 0 0 1〉 axial channel in highly oriented pyrolytic graphite (HOPG) crystals doped with 0.32 at.% B. The B atoms are detected by measuring α-particles which are emitted as a result of a nuclear reaction ¹¹B(p,α)αα. It is clearly demonstrated that most of B atoms are shadowed behind the 〈0 0 0 1〉 C atomic rows. Taking account of the already reported experimental results on a change of lattice parameters by B-doping, it is concluded that most of B atoms are located at substitutional sites. It is also observed that B-doping introduces lattice strain on the c-plane. In addition, the presence of a small portion of interstitial B atoms is suggested.     

NiCoFe/C cathode electrocatalysts for direct ethanol fuel cells

A direct ethanol fuel cell (DEFC), which is less prone to ethanol crossover, is reported. The cell consists of PtRu/C catalyst as the anode, Nafion^® 117 membrane, and Ni–Co–Fe (NCF) composite catalyst as the cathode. The NCF catalyst was synthesized by mixing Ni, Co, and Fe complexes into a polymer matrix (melamine-formaldehyde resins), followed by heating the mixture at 800 °C under inert atmosphere. TEM and EDX experiments suggest that the NCF catalyst has alloy structures of Ni, Co and Fe. The catalytic activity of the NCF catalyst for the oxygen reduction reaction (ORR) was compared with that of commercially available Pt/C (CAP) catalyst at different ethanol concentrations. The decrease in open circuit voltage (V_oc) of the DEFC equipped with the NCF catalysts was less than that of CAP catalyst at higher ethanol concentrations. The NCF catalyst was less prone to ethanol oxidation at cathode even when ethanol crossover occurred through the Nafion^®117 film, which prevents voltage drop at the cathode. However, the CAP catalyst did oxidize ethanol at the cathode and caused a decrease in voltage at higher ethanol concentrations.     

Fabrication of damascene Cu wirings using solid acidic catalyst

The copper damascene process is one of the most promising technologies for fabricating Cu wirings for electronic devices such as LSIs. In this research, the fabrication of damascene Cu wirings was conducted using solid acidic catalyst. When a Cu-plated wafer, whose oxide is a basic oxide is dipped into a mixture of oxidizing solution and acidic solution, surface atoms are ionized and etched off into the solution. However, because conventional nonelectrolytic etching does not have a reference surface, it is difficult to utilize for planarization. Therefore, a new nonelectrolytic machining method using a cation-exchange fabric instead of an acidic solution was developed. To be more precise, the planarization of a Cu-plated wafer was carried out by rubbing with the cation-exchange fabric in ozone water. Basically, this method exploits chemical reactions so that the physical properties of the workpiece surface are not deteriorated. Furthermore, this method uses no chemicals except for ozone water, which easily dissociates into water and oxygen molecules; thus, this method is a low-cost, environmentally friendly process. In this paper, as a preliminary experiment, the nonelectrolytic etching of a Cu sample using solutions of O₃ and CO₂ was carried out to inspect the dependence of the etching rate on [O₃] and [H⁺]. The results indicate that the etching rate increased as [O₃] and [H⁺] increased. When [H⁺] was high relative to [O₃], a smooth etch-pit-free surface was achieved. Next, nonelectrolytic etching using a cation-exchange fabric was carried out, and properties similar to those in the case of etching using solutions were obtained. Finally, damascene Cu wirings were fabricated using ozone water and a cation-exchange catalyst.     

Keratinocyte differentiation is induced by cell-permeant ceramides and its proliferation is promoted by sphingosine

Antibody titres against Plasmodium falciparum and P. vivax were examined using the indirect fluorescent antibody test (IFAT) for 183 Gidra-speaking adults and adolescents in four ecologically different villages of lowland Papua New Guinea. The findings highlight that 1) in Gidraland P. falciparum was more prevalent than P. vivax, 2) the proportion of antibody titres of 1:64 or higher markedly differed among the villages, ranging from 35.3% to 100% for males and from 31.6% to 100% for females, and 3) in the two villages with high prevalences, these were higher among males than females. The inter-village and sex differences can be largely explained by microenvironmental conditions and behavioural patterns of the population. The population-based analyses of this study intend to contribute to a better understanding of the prevalence of malaria in human-environment settings and thus to the planning of malaria prevention.     

Twin-Related Tetragonal Variants in Yttria Partially Stabilized Zirconia

Crystals of yttria partially stabilized zirconia were grown by the arc-image floating-zone technique and studied by transmission electron microscopy. Crystals annealed at 1700°C consist of tetragonal precipitates and a cubic matrix. The platelike domains in a precipitate are twin-related tetragonal variants stacked alternately parallel to the (011) twin plane. The axial relations between the tetragonal precipitate and the cubic matrix are [100]_tetragonal|[100]_cubic, [011]_tetragonal|[011]_cubic.