The in-plane-oriented BaPrO3-δ thin film with mixed valence states has been prepared on an Al2O3 (0001) substrate by RF magnetron sputtering. The lattice constant decreases with increasing film thickness. The thin film has the mixed valence states of Pr4+ and Pr3+. The ～168 nm thickness film with small lattice constant exhibits high electrical conductivity and low activation energy of 0.58 eV at dry atmosphere. The wet-annealed thin film shows high proton conduction, which is required as electrolyte of solid oxide fuel cell, at 300 ～ 600 °C.
The adsorption behaviors of cesium ion on silk fibroin (SF) fibers in aqueous solution were investigated for applications to purify the contaminated water by radioactive cesium ion. The ability of adsorption of cesium was smallest among the other metal ions compared. Tendency of such adsorption was explained in terms of the stability of the combination between the ions and the SF. The optimal condition for adsorption of cesium ion was searched. The thermodynamic adsorption behavior was discussed using the Langmuir and the Freundlich equilibrium adsorption models.
ZrN is a possible candidate for the diluent material for the nitride fuels containing transuranium elements. Pellets of inert matrix material ZrN, and surrogate nitride fuel material (Dy0.5Zr0.5)N, are fabricated for the purpose of investigating crystal structure. Lattice parameters of (Dy1-xZrx)N followed the Vegards’s low, in spite of large lattice mismatch (～ 7 %) between DyN and ZrN. Local structure analysis was performed by X-ray absorption fine structure and atomic pair-distribution function methods. Although lattice parameter of Dy0.5Zr0.5N is larger than that of ZrN, Zr-N nearest neighbor bond distance of Dy0.5Zr0.5N is shorter than that of ZrN. The complex local structure of DyN and ZrN is related to the preferable effect of ZrN.
((1-x)(Na0.50K0.45Li0.05)NbO3-x(Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (NKLN-CZT, x = 0-0.08) powders were synthesized by the malic acid complex solution method, and NKLN-BCZT solid solutions were then fabricated using a conventional solid-state reaction technique. The piezoelectric properties of the resulting materials were measured, and the x = 0.01 sample was found to exhibit the maximum longitudinal-length-mode piezoelectric coefficient and radial-mode electromechanical coupling factor values of 177 pC/N and 33%, respectively. On the basis of both the results for piezoelectric properties and for the local structural analysis using high-energy X-ray diffraction (HEXRD), measuring the degree of distortion of NbO6 octahedra using HEXRD can be an effective method for the development of high-performance piezoelectric materials.
When a metal is added to a layer of diamond-like carbon (DLC), the resulting particle size of the metal within the film usually depends on the metal content. To be more flexible in influencing the size of the particles that result when using a plasma based preparation process two different approaches were tested: on the one hand the combination of a gaseous precursor with magnetron sputtering, where a nanostructured coating is applied on top of the sputter target in advance; on the other hand, the addition of preformed metallic nanoparticles to a liquid. In both cases, the nanoparticles or -structures were prepared by a wet chemical process, whereas the DLC layer was prepared by a plasma process. The produced metal-containing DLC films were characterized regarding their metal content and distribution as well as regarding possible contaminations from the chemical preparation process.
Zinc-containing diamond-like carbon films were prepared by a combination of magnetron sputtering of a zinc target and plasma source ion implantation and deposition in a hydrocarbon atmosphere. The effect of the preparation conditions on the film properties, such as surface morphology, film structure, Zn content, hardness and friction coefficient, was evaluated. A wide range of Zn contents can be realized, with films becoming rougher and softer with increasing Zn content. The films possess remarkable Zn-rich features as observed in SEM images. Depending on the Zn concentration, the features evolve from dots into more network-like structures.
To investigate the thermal stability of the ion-irradiation induced amorphous state in bulk samples of Ni3Nb and Ni3Ta intermetallic compounds, they were irradiated with 16MeV Au ions at room temperature, and were subsequently annealed up to 773K and 973K, respectively. The lattice structures of the irradiated samples and the annealed samples were examined by means of the grazing incidence x-ray diffraction (GIXD). The hardness of the samples was also measured as a function of annealing temperature. The amorphous state induced by room temperature irradiation recovers to the intrinsic ordered structure for Ni3Nb samples at 773K. On the other hand, for Ni3Ta samples, the irradiation-induced amorphous state doesn’t recover to the intrinsic ordered structure even at 973K, but it changed to another lattice structure by the subsequent annealing. The values of the hardness decreased by the subsequent annealing. For Ni3Nb samples, the irradiation at elevated temperatures was also performed. The higher temperature irradiation tends to suppress the amorphization more strongly in Ni3Nb samples. As a result, the increase in hardness becomes smaller for the higher temperature irradiation.
To achieve addition of functional group to poly(ε-caprolactone) (PCL) chain, we conducted direct methylenation of PCL carbonyl group using the Petasis reagent. First, various methylenation reactions of benzyl-terminated PCL were carried out by changing the reaction temperature, reaction time, and the ratio of the reagent to the carbonyl groups of PCL. The results indicated that relatively shorter reaction times (1 h) and higher temperatures (120 ℃) are preferable for direct methylenation without cleavage of the polymer chains and undesired gelation. Thermal properties of the methylenated PCL were also studied to investigate their effect on crystallinity, compared with the initial PCL. It was found that increased methylenation leads to reduction in the crystallinity, while the polymer chain alignment in the polymer crystal could be disturbed by the addition of methylene groups. To confirm the functionalization of methylene groups in the PCL chain, the thiol-ene reaction model was applied using α,α’-azobisisobutyronitrile and thioglycolic acid under N2 atmosphere. Successful carboxyl group attachment suggests that the methylene groups would be useful for further functionalization of the PCL chain for the design of new biodegradable aliphatic polyesters.
We have applied the Marimo-like carbon as a catalyst support for the polymer electrolyte fuel cell (PEFC) electrodes. The Marimo-like carbon is composed of carbon nanofilaments (CNFs) which are type of cup-stacked fibrous carbon material. The Pt catalyst was loaded onto the CNF support by the modified nanocolloidal solution technique without any acid and/or heat pretreatments. In order to obtain fin e and highly dispersed Pt particles on the CNFs surface, we have modified a conventional nanocolloidal solution method. Carbon materials should be added to the solution system before formation of the Pt nanocolloidal particles. We have investigated the influence of the concentrations of both the chloroplatinic acid and sodium borohydride solution on the formation of the Pt nanoparticles in this study. Pt nanoparticles deposited on the CNFs were observed by the transmission electron microscope (TEM) and the catalyst performance of the Pt nanoparticles on the CNFs were investigated by the cyclic voltammetry (CV). A lower chloroplatinic acid concentration and higher sodium borohydride concentration produced fine Pt particles with higher dispersion and better catalytic activity than other.
The phenomenon of photon up-conversion (UC) has attracted considerable research interest for its application to fields as diverse as bioimaging and photovoltaics. In this study, we report on the concentration dependence of Zn2TiO4:Yb3+, Er3+ on UC emission. Upon investigating Mg, Ti, and Zn as potential UC host materials, we find that the combination of Ti and Zn yields the most increase in luminous efficiency. Further, as a result of varying the molar ratio, a high-intensity emission spectrum is observed for the ratios of Zn : Ti = 44 : 56 and 50 : 50. The samples prepared in this study exhibit excellent moisture resistance, and they can be utilized in solar cells and lighting equipment.