Lattice volume expansion or amorphization renders EuTiO3 ferromagnetic, although the stable phase of crystalline EuTiO3 is an antiferromagnet. The lattice volume expansion is induced into the crystalline EuTiO3 thin film by utilizing the lattice mismatch between the thin film and a substrate. The magnetization at low temperatures monotonically increases with an increase in lattice volume for the crystalline EuTiO3 thin film, coincident with the results of calculations based on the hybrid Hartree–Fock density functional approach. The ferromagnetic interaction between Eu2+ ions is enhanced by the amorphization as well; the amorphous EuTiO3 thin film becomes a ferromagnet, and the Curie temperature is higher for amorphous Eu2TiO4 than for its crystalline counterpart. The phenomenon, that is, the volume expansion- and amophization-induced ferromagnetism, is explained in terms of the competition between ferromagnetic and antiferromagnetic interactions among Eu2+ ions.

A nanoparticle catalyst of PtRuAu/C was synthesized by including an Au precursor in the radiolytic process for preparing a PtRu/C catalyst. Their methanol oxidation activity and electrochemical durability were measured by linear sweep voltammetry before and after potential cycling treatment. PtRuAu/C had a significantly higher durability than PtRu/C while maintaining a comparable high activity. The morphology and substructure of the nanoparticles were investigated by energy-dispersive x-ray spectroscopy, x-ray diffraction, and x-ray absorption fine structure spectroscopy. Metallic nanoparticles with diameters of about 2 nm were obtained; they probably had Pt-core/PtRu-shell structures. Transmission electron microscopy observations after potential cycling revealed that 2-nm-diameter nanoparticles containing Au did not coarsen, whereas nanoparticles without Au coarsened significantly to 3.7 nm. Some crystal defaults were observed in the coarsened particles, implying that the coarsening was caused by Ostwald ripening. The Au addition to catalyst particles consisting of PtRu inhibits coarsening and consequently improves the electrochemical durability.

Bulk EuTiO3 is known as a compound in which spin and soft phonon mode is strongly coupled. Recent theoretical study suggests that application of stress or formation of strain leads to a drastic change in magnetic and dielectric properties of EuTiO3 and that so-called multiferroic properties emerge under such a situation. In the present study, effect of strain induced by a substrate, on which EuTiO3 thin film is deposited, on the magnetic properties of the film has been experimentally examined. By using a pulsed laser deposition method, EuTiO3 thin film has been deposited on different kinds of substrate, i.e., LaAlO3, SrTiO3, and DyScO3; the lattice parameter of these compounds is smaller than, just the same as, and larger than that of EuTiO3, respectively. X-ray diffraction analysis confirms that the strain induced in the plane of as-deposited EuTiO3 thin films on different substrates is coincident with the lattice parameter of the substrate compounds. Also, all the as-deposited EuTiO3 thin films manifest elongation of lattice in a direction perpendicular to the film surface. Temperature dependence of magnetization indicates that all the thin films exhibit ferromagnetic behavior at low temperatures. The magnetization at 2 K under a magnetic field of 100 Oe is the highest for EuTiO3 on DyScO3 and the lowest for EuTiO3 on LaAlO3. The experimental result is coincident with the first-principles calculations which predict that ferromagnetic spin configuration becomes more stable as the lattice volume of EuTiO3is increased.

Nanoparticle catalyst of PtRuAu/C for direct methanol fuel cell anodes was synthesized by a radiolytic process. Its methanol oxidation activity and the electrochemical durability were evaluated by using the linear sweep voltammetry and the cyclic voltammety. The Au addition significantly improved the durability in comparison with PtRu/C catalyst without losing its high activity. The atomic structure was characterized with techniques of the transmission electron microscopy, the X-ray diffraction, the X-ray fluorescence spectroscopy and the X-ray absorption fine structure. These results implied that the arrangement of Pt and Ru atoms in the PtRuAu/C has no significant difference from that without Au, possessing a structure of Pt rich core and PtRu alloy shell. We concluded that the improvement in durability could originate from these PtRu nanoparticles decorated with Au, but not from particles with high Au contents.

In order to clarify the effect of mineral alteration on nuclide migration, we examined the processes, mechanisms, and kinetics of chlorite weathering, and the uranium concentrations in minerals and rocks at Koongarra, Australia. The observed concentrations of uranium in rocks were compared to those calculated. The sequence of chlorite weathering may be simply expressed as a chlorite → vermiculite → kaolinite conversion. These minerals occur as a function of depth, which corresponds well to uranium concentrations on the meter scale. Iron minerals, closely related to the uranium redistribution, are released during the weathering. The first-order kinetic model of the weathering process suggests that the weathering rate is not constant but time-dependent. The uranium concentrations are qualitatively proportional to the extent of the weathering; the weathered part having higher uranium concentration. Uranium mainly occurs with iron minerals, and sub micron sized saléeite, a uranyl phosphate, is one of the most probable uranyl phases associated with the iron minerals. The uranium fixation mechanisms are probably saléeite microcrystal coprecipitation and sorption to the iron minerals. Our model, which describes uranium concentrations in rocks as a function of time, shows that the transition zone (a vermiculite dominant area) plays an important role in the uranium migration. We have established that weathering of chlorite has affected the redistribution of uranium for more than one million years. The present study demonstrates the significance of mineral alteration when we estimate nuclide migration for geologic time.

A modelling study was carried out to understand the effect of rock alteration on uranium radionuclide concentrations in rocks, in the vicinity of the Koongarra ore deposit, Australia. The one-dimensional, advection-dispersion-sorption model considers two important factors resulting from the process, mechanism and rate of chlorite weathering, one type of rock alteration that has occurred over a million-year period; (a) the changes in the distribution coefficients of uranium and thorium over time, and (b) that in rock porosity. The distribution coefficient and rock porosity at a given time, are expressed as average values of those of the coexisting minerals. By assuming a Darcy velocity of 0.9 m/y and an initial uranium concentration in the groundwater of 0.5 ppm, similar to present-day values, we were able to derive, from the finite-element modelling, uranium concentrations in the rock which are in good agreement with observed values. The calculated values of 230Th/234U activity ratios show a similar trend to those observed, although more experimental data are necessary to confirm the similarity. However, in the absence of the rock alteration, the calculated results did not agree with those observed. The present study suggests that rock alteration should be included in models used to predict uranium migration over long, geologic timescales.

The chemical stability of the surface of stainless steel (SUS) 304 in acid immersion tests is greatly improved by the laser implant-deposition (LID) process, i.e., the simultaneous deposition and incorporation of silicon by KrF excimer laser irradiation. The etching depths of the treated samples in 1.32 N HCl solution are substantially zero at the laser irradiation conditions of more than 40 pulses and of more than 400 mJ/cm2 at the surface. By the quantitative verification of cathodic polarization in 1 N H2SO4, the highest polarization resistance is estimated to be 26.7 times that of the nontreated sample.

The American involvement in Viet Nam has not unnaturally led to the assumption that Chinese expansionism has had a long history of activity in that region, and not a few American writers, notably of journalistic fiber, have come out openly to say that it is really the Chinese that the American forces are fighting against, citing at the same time, hundreds of, even a thousand, years in which Viet Nam was under the control of the Chinese, and innumerable occasions on which it was invaded by the Chinese, that Chinese aggression, on the basis of encroachments into Viet Nam, is a proven fact, and unarguable. On the other hand, there have been a few, notably scholars, who have contended otherwise, that, although imperialism may have infected certain Chinese dynasties, the dominant characteristic, indeed, in the territorial expansion of the Chinese has been their willingness to accept any “barbarian” outsider who would but learn Chinese and accept Chinese customs, as Chinese; also, that China itself is composed of people who are descended from “barbarians” absorbed into the Chinese state by the acculturation process; that the Chinese, while indeed invading their peripheral states on frequent occasions, have done so almost without exception on provocations, such as coups, or attempted coups of the existing friendly-to-China dynasties, and so forth.