Transactions of the Materials Research Society of Japan
Online ISSN : 2188-1650
Print ISSN : 1382-3469
ISSN-L : 1382-3469
43 巻 , 6 号
選択された号の論文の9件中1~9を表示しています
Memorial Article
Regular Papers
  • Naoki Igawa, Katsuaki Kodama, Tomitsugu Taguchi, Yukihiko Yoshida, Tak ...
    2018 年 43 巻 6 号 p. 329-332
    発行日: 2018/12/01
    公開日: 2018/12/01
    ジャーナル フリー

    We carried out the neutron powder diffraction study to reveal the local disorder in the proton conductor BaSn0.5In0.5O2.75. We analyzed this material by the combination of the Rietveld refinement and the maximum entropy method and confirmed that this material has the cubic structure with the space group of Pm3m, and that Sn and In atoms randomly occupy 1b site. However, the atomic pair distribution function (PDF) indicated that this material can be fitted well by the structural model with a tetragonal phase, P4/mmm from the original-cubic structure below the maximum distance between a pair of atoms, rmax of 6 Å, and as rmax increases, this disorder is released and that structure changes to the original-cubic structure. We found that the local structural disorder is caused by the displacement of Ba and O atoms.

  • Y. Natsume, Y. Komori, K. Itoh, K. Kurihara
    2018 年 43 巻 6 号 p. 333-338
    発行日: 2018/12/01
    公開日: 2018/12/01
    ジャーナル オープンアクセス

    A phase separation in a dispersion of two kinds of particles has recently been reported to result from entropic interactions between particles and between particles and surfaces in closed spaces. In many cases, the phase separation took place localization of large particles in the vicinity of a compartment. However, phase separation in closed systems has been limited to systems in which the number of small particles was much larger than the number of large particles. In contrast, we prepared giant vesicles (GVs) in which the volume fraction of large particles was higher than that of the small particles. As a result, we observed a new phenomenon in which small particles localized spontaneously and stably in the vicinity of the vesicular membrane. To explain this phenomenon theoretically, we assumed that an equilibrium osmotic pressure was realized between an outer phase containing a relatively large number of small particles and another inner phase. The osmotic pressure was estimated from the free energy change due to the excluded-volume effect. There was good agreement between the distribution ratio of the number of large and small particles in the phases calculated from fluorescent microscopy images and the prediction of the osmotic equilibrium model.

  • Kazuo Kasatani, Yuki Morita
    2018 年 43 巻 6 号 p. 339-342
    発行日: 2018/12/01
    公開日: 2018/12/01
    ジャーナル フリー

    We studied fluorescence from dyes adsorbed on organic nanoparticles. Nanoparticles of 1,4-bis(2-methylstyryl)benzene (bis-MSB) were made by a reprecipitation method. Fluorescent dyes, rhodamine 6G, rhodamine 640, and coumarin 153, were used to adsorb on nanoparticles of bis-MSB. Nanoparticles of bis-MSB were excited by ultraviolet light to measure fluorescence spectra. Adsorption of fluorescent dye on the nanoparticles reduced the fluorescence from bis-MSB nanoparticles, and fluorescence of adsorbed dye appeared. However, large amount of fluorescent dye reduced the fluorescence of adsorbed dye.

  • Y. Nakabayashi, Y. Umeda, T. Nagai, K. Tashiro, H. Honma, H. Kouzai
    2018 年 43 巻 6 号 p. 343-347
    発行日: 2018/12/01
    公開日: 2018/12/01
    ジャーナル フリー

    High adhesion strength between Acrylonitrile Butadiene Styrene (ABS) plastic and plated metal has been conventionally obtained by chromic acid etching in manufacturing industry. However, in recent years, hexavalent chromium becomes the target as an environmental regulatory substances. Thus, the establishment of a chromium-free pretreatment method is expected. Electrolyzed sulfuric acid (ESA) is a unique oxidizer alternative to the chromic acid. Therefore, we have been trying to apply ESA to treat the surface of ABS plastic. Depending on the sulfuric acid concentration in ESA solution, modification effects such as changing the surface morphology and introducing the functional groups were different. The ESA in which the concentration of sulfuric acid is 75 wt% and 80 wt% can change ABS resin surface in quality to be hydrophilic from hydrophobic. Also, adhesion strength between plating metal film and the plastic was obtained maximum 1.2 kN/m. Mechanism of high adhesion was anchor effect with cohesion failure. Therefore, this environmentally friendly surface modification method is expected in industrial use.

  • Qiyan Zhang, Mitsuhiro Honda, Yo Ichikawa
    2018 年 43 巻 6 号 p. 349-353
    発行日: 2018/12/01
    公開日: 2018/12/01
    ジャーナル フリー

      The structure of seed layers has been considered as a significant factor to dictate the subsequent growth of ZnO nanorods. We carefully studied seed layer structures such as crystallinity, surface crystal orientations, and grain sizes to investigate their effect on ZnO nanorod growth during hydrothermal synthesis. The structure of seed layers was changed by controlling their thickness and further annealing treatments at 200-1000 °C. Among several parameters of seed layer structure, the grain size and the surface crystal orientation were found to make a noticeable change in the morphology of ZnO nanorods. Thick ZnO nanorods were produced on large grains while densely aligned products were observed on the seed layer surface with c-axis orientation. In addition, at the early stage of synthesis, we observed ZnO nanorods with a diameter much smaller comparing to the size of grains consisting of poly- and single crystal. This explains that the nucleation of ZnO crystals start on c-axis oriented domains, and they grow in a length favorably and in diameter gradually, resulting in the formation of ZnO nanorods with the integration of tightly aligned products.

  • Masahiko Nagaki, Taishi Nara, Shuto Sakaiya, Kanako Yamanouchi, Takaki ...
    2018 年 43 巻 6 号 p. 355-358
    発行日: 2018/12/01
    公開日: 2018/12/01
    ジャーナル フリー

    Biotransformations of citronellal and geranial were carried out using Botrytis cinerea as a biocatalyst. Biotransformation of citronellal using B. cinerea produced 100% citronellol on the third day. Conversely, no reaction was observed when citronellol was added to culture containing B. cinerea. Biotransformation of geranial using B. cinerea produced almost 100% geraniol after 18 h. Biotransformation of citral (mixture of neral and geranial) using B. cinerea produced almost 100% citrol (nerol and geraniol) on the third day. Examination of the antimicrobial activity of the related compounds revealed that citronellal and citronellol showed activity against Escherichia coli (ATCC 25922), methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans but showed no activity against enterohemorrhagic Escherichia coli (EHEC) or Pseudomonas aeruginosa. The same findings were obtained using the sensitive disc method: citronellal and citronellol showed activity against Escherichia coli (ATCC 25922), MRSA and Candida albicans but not EHEC or Pseudomonas aeruginosa.

Errata
Regular Papers
  • Naofumi Nishikawa, Satoshi Takeichi, Takanori Hanada, Shuya Tategami, ...
    2018 年 43 巻 6 号 p. 361-364
    発行日: 2018/12/01
    公開日: 2018/12/01
    ジャーナル フリー

    Ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) composite (UNCD/a-C:H) films possess the following specific characteristics: (a) the appearance of additional energy levels in diamond bandgap and (b) large absorption coefficients ranging from visible to ultraviolet, both of which might be due to large number of grain boundaries between UNCD grains and those between UNCD grains and a-C:H. Owing to them, UNCD/a-C:H films are expected to be applied to photovoltaics such as UV sensors. Actually thus far, we have fabricated pn heterojunction diodes comprising p-type UNCD/a-C:H films and n-type Si substrates, and confirmed their photovoltaic action. In this study, the minority carrier lifetime, which is an important factor for photovoltaics, was experimentally measured by microwave reflected photoconductivity decay, and it was estimated to be 0.21 and 0.43 μs for UNCD/a-C and UNCD/a-C:H, respectively. In addition, on the basis of the previous work on the heterojunctions, the effects of hydrogenation on the photovoltaic action of the heterojunctions were studied. The photocurrent apparently increases with an enhancement in the hydrogenation of UNCD/a-C:H films, which might be because dangling bonds in the UNCD/a-C:H films, which act as photogenerated-carrier trap centers, are terminated by hydrogen atoms.

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