Transactions of the Materials Research Society of Japan
Online ISSN : 2188-1650
Print ISSN : 1382-3469
ISSN-L : 1382-3469
43 巻 , 4 号
選択された号の論文の8件中1~8を表示しています
Regular Papers
  • Haruki Yamane, Yuji Kondo, Yasuyoshi Isaji, Keisuke Takeda, Masanobu K ...
    2018 年 43 巻 4 号 p. 213-217
    発行日: 2018/08/01
    公開日: 2018/08/01
    ジャーナル フリー

    The perpendicular magnetic properties of [CoPt/AZO/Ag] multilayered films were investigated under polar Kerr measurement conditions. The magnetic properties were influenced by AZO layers formed upon the top and bottom surfaces of CoPt magnetic layer. The insertion of AZO intermediate layer into the CoPt/Ag interface improved the perpendicular magnetic properties, and it was attributed to the improvement of the CoPt crystallinity. In contrast, the AZO overcoat layer which was directly formed on the top of the CoPt layer reduced the perpendicular magnetic anisotropy. This magnetic deterioration was suppressed by the oxidation of the CoPt surface. A plasma oxidation process provided good perpendicular magnetic properties with an ideal square out-of-plane Kerr loop.

  • Shigeki Watanabe, Akihiko Shimada, Satoshi Watanabe, Hirofumi Hanaoka, ...
    2018 年 43 巻 4 号 p. 219-222
    発行日: 2018/08/01
    公開日: 2018/08/01
    ジャーナル フリー

      Dry distillation has been mainly used for the isolation of bromine-76 (76Br), a clinically potent radionuclide for positron emission tomography (PET). However, dry distillation systems are not considered suitable for an automated isolation module, which is necessary for routine clinical production. Therefore, a new dry distillation system including a water trap for the recovery of 76Br was investigated. Prior to isolation studies, isotopically enriched Cu2 76Se, the target material for 76Br production, was prepared by heating a mixture of Cu and 76Se under high vacuum; formation of Cu2 76Se was confirmed by X-ray diffractometer (XRD). Isolation studies using 77Br demonstrated reasonable recovery efficiency (66.5 ± 5.3%) from the new system. Large-scale isolation studies using 76Br led to recovery of highly pure 76Br with radioactivity on the order of GBq under optimized conditions. This improved dry distillation method shows promise as a future automated isolation process.

  • Romy Dwipa Y. Away, Sota Fujii, Takayuki Ban, Yutaka Ohya
    2018 年 43 巻 4 号 p. 223-228
    発行日: 2018/08/01
    公開日: 2018/08/01
    ジャーナル フリー

    The mesoporous titania was prepared by sol gel method using titania sol and silica sol as precursor. Mesoporous titania thin film was made by removing of silica in TiO2-SiO2 composite film using HF leaching. The photocatalytic performance was studied by photodegradation methylene blue in water under UV irradiation. The volume ratio of silica and the calcination temperature influenced the photoactivity. SEM images revealed as the proportion of silica increases, the proportion of the aggregated parts increase and the crystal phase was changed. The BET surface area, pore volume and pore diameter of the TiO2-SiO2 7:3 at 700℃ were found to be 169.4 m2/g, 0.29 cm3/g and 3.8 nm, respectively. The best photocatalytic activity of mesoporous TiO2 thin films is obtained when the volume ratio of oxide TiO2-SiO2 is 7:3 and heated at 900℃, due to the increased crystallinity of anatase and also the existance of anatase and rutile phase.

  • Toshio Konno, Takatsugu Wakahara, Chika Hirata, Kun’ichi Miyazawa, Kaz ...
    2018 年 43 巻 4 号 p. 229-232
    発行日: 2018/08/01
    公開日: 2018/08/01
    ジャーナル フリー

    C60-C70 two-component fullerene whiskers were synthesized by a liquid-liquid interfacial precipitation (LLIP) method using various ratios of C70 to C60, and were analyzed for their dimensions using scanning electron microscopy (SEM). The diameters and the lengths of the C60-C70 fullerene whiskers show ever-increasing W-type graphs which have two local minimal values, respectively. The shape of the graphs were resulted from changing of crystal growth rate with varying of fullerene compositions of mother solution. The carcinogenicity of C60-C70 fullerene whiskers can be evaluated using the C60-C70 fullerene whiskers whose dimensions and physical factors are specified, and they will be applied to various products such as the active layer materials of solar cells and the anchor materials.

  • Koretaka Yuge
    2018 年 43 巻 4 号 p. 233-236
    発行日: 2018/08/01
    公開日: 2018/08/01
    ジャーナル フリー

      We propose theoretical approach based on combination of graph theory and generalized Ising model (GIM), which enables systematic determination of extremal structures for crystalline solids without any information about interactions or constituent elements. The conventional approach to find such set of structure typically employs configurational polyhedra (CP) on configuration space based on GIM description, whose vertices can always be candidates to exhibit maximum or minimum physical quantities. We demonstrate that the present approach can construct extended CP whose vertices not only include those found in conventional CP, but also include other topologically and/or configurationally characteristic structures on the same dimensional configuration space with the same set of figures composed of underlying lattice points, which therefore has significant advantage over the conventional approach.

  • Shota Shingai, Naoki Wakuzawa, Shun Miyata, Izuru Kobayashi, Nobukatsu ...
    2018 年 43 巻 4 号 p. 237-240
    発行日: 2018/08/01
    公開日: 2018/08/01
    ジャーナル フリー

    The preparation method and electrochemical characterization of the non-platinum catalysts for a cathode in polymer electrolyte fuel cells (PEFCs) obtained from polymer composites that had been synthesized by polycondensation reaction using tetracarboxy cobalt phthalocyanine and diamino-functionalized aromatic compounds such as p-phenylenediamine or 1,5-diaminonaphthalene, followed by baking were reported. The electrochemical properties of the obtained catalysts were evaluated through the oxygen reduction activity (ORA) by linear sweep voltammetry (LSV) measurement. It was revealed that the ORA of the catalysts prepared in the present study depended on the quantity of nitrogen content in the catalysts.

  • K. Honma, T. Masuyama, T. Takahashi, H. Iizuka, M. Shishido
    2018 年 43 巻 4 号 p. 241-244
    発行日: 2018/08/01
    公開日: 2018/08/01
    ジャーナル フリー

    Rice hull, which is one of the agricultural wastes in Japan, has been proposed for reuse from the viewpoint of environment protection. Thus the authors developed a porous carbon (RHSC: Rice Hull Silica Carbon) material utilizing the porous structure of rice hull. RHSC has core competence such as low coefficient of friction and water resistance. The authors developed a bearing (RHSC bearing) which is excellent in weather resistance and water resistance. RHSC bearings are made of agricultural waste as raw material, and it is possible to immobilize carbon. In addition, in order to suppress wear due to dry friction, we have developed oil - retaining RHSC bearing which retains lubricating oil in a porous structure. However, the optimum manufacturing conditions of oil-retaining RHSC, the performance of the RHSC bearing and oil-retaining RHSC bearing has not been evaluated. In this study, the authors focused on the oil impregnation using vacuum and ultrasonic waves. The optimum manufacturing conditions and the relationship between oil content and impregnation time were investigated. In addition, we conducted an actual machine test as a wheelchair bearing and evaluated the performance of the RHSC bearing.

  • Takashi Kosone, Yu Onishi, Syogo Okuda, Ayaka Haigo, Takafumi Kitazawa
    2018 年 43 巻 4 号 p. 245-248
    発行日: 2018/08/01
    公開日: 2018/08/01
    ジャーナル フリー

    New 2-dimensional (2-D) coordination polymers, {CoII(3-fluoropyridine)2[AuI(CN)2]2} and doped material {FeIIxMII1-x(3-fluoropyridine)2[AuI(CN)2]2} (M = Mn, Co) were synthesized and characterized crystallographically and magnetically. The 2-D layer structure is composed by infinite cyano bridged Fe[Au(CN)2]2. The layers are combined with another layer by strong aurophilic interactions defining bilayers. Compound of 100 % Fe ions undergoes a complete two-step spin transition with large hysteresis loop. Doped compounds shows the characteristic of gradual spin transition without hysteresis loop. The metal doping effect on spin transition properties are discussed.

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