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91.
Maher M. Al-Dabbas Khaled Al-Ismail Kanefumi Kitahara Naoya Chishaki Fumio Hashinaga Toshihiko Suganuma Kenjiro Tadera 《Food chemistry》2007,104(2):734-739
The DPPH radical-scavenging activity of 25 inorganic salts, two buffer systems, and crude water extract of aerial parts of Varthemia (Varthemia iphionoides) before and after resins purification were investigated. Eight of the 25 inorganic salts tested quenched the DPPH radical colour. Na2S2O3 and FeCl2 showed markedly high DPPH colour-quenching activity, with inhibition of 65.3% and 47.7% respectively, at a concentration of 10 μg/ml. Four salts slightly increased the intensity of DPPH radical colour. The rest of tested salts, acetate buffer, and phosphate buffer at a concentration less than 0.1 mM did not affect DPPH radical colour. The DPPH radical-scavenging activity of BHT and catechol was considerably affected by the concentration of phosphate buffer (pH 7.0), and by acetate buffer (pH 5.0) at concentrations more than 0.01 mM in the case of BHT only. The DPPH radical-scavenging activity of a crude water extract of aerial parts of Varthemia iphionoides was much higher than that of an extract desalted by cation-exchange resin, indicating that iron ions apparently elevated the DPPH radical-scavenging activity of the extract. Therefore, desalting of plant extracts is important in order to obtain the true value of DPPH radical-scavenging activity. 相似文献
92.
Masashi Ikegami Jun Suzuki Kenjiro Teshima Masahide Kawaraya Tsutomu Miyasaka 《Solar Energy Materials & Solar Cells》2009,93(6-7):836-839
Large-area integrated modules of flexible plastic type dye-sensitized solar cell (DSC) have been fabricated based on polyethylene naphthalate (PEN) film for practical applications such as ubiquitous power sources. From the view point of improving durability, composition of organic solvent-based electrolytes has been investigated. As a result, a plastic DSC module using LiI-free electrolyte maintained its energy conversion efficiency of 2% over 220 h under the accelerated condition of 55 °C and 95% relative humidity. 相似文献
93.
Mikinori Hotta Junichi Tatami Katsutoshi Komeya Cheng Zhang Takeshi Meguro Mark R. Terner Yi-Bing Cheng 《Journal of the American Ceramic Society》2008,91(3):860-864
Carbothermal reduction–nitridation (CRN) of SiO2 –Al2 O3 –CaO powders was performed under various firing conditions to investigate the formation process of Ca-α sialon hollow balls composed of nanosized particles. Scanning electron microscopy and transmission electron microscopy observations of the samples obtained at different firing temperatures confirmed that solid spherical particles were formed at the early stage of the reaction, and nanosized particles were subsequently produced on the surface of these solid balls. From X-ray diffraction and energy-dispersive spectrometry analyses, it was found that the solid balls initially formed at 1450°C were mainly amorphous and contained Si, Al, Ca, O, and a small amount of N. Further nitridation at 1450°C gradually converted the solid balls into Ca-α sialon hollow balls over time. The results revealed that the formation of Ca-α sialon hollow balls depends on the formation of solid balls from the Si–Al–Ca–O liquid phase at the initial stage of the CRN process. 相似文献
94.
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96.
T. Yokoyama T. Meguro K. Kato S. Okazaki D. Ito J. Tatami T. Wakihara K. Komeya 《Journal of Electroceramics》2013,31(3-4):353-359
The preparation and electrical properties of a sintered body consisting of cubic spinel oxide MnFeNiO4 were investigated. A sintered body with cubic spinel and NaCl-type oxides prepared at 1400 °C in Ar could be converted to one consisting of monophase cubic spinel oxide by oxidation at 1000 °C for more than 48 h in air. The electrical conductivity of a sintered body consisting of monophase cubic spinel oxide was confirmed to increase exponentially with increasing temperature, indicating that the oxide has intrinsic negative temperature coefficient (NTC) thermistor characteristics. The electrical conduction of the oxide was concluded to be controlled by the small polaron hopping mechanism. Changes in electrical conductivity, mobility, and charge carrier jump frequency in temperature dependence at 400 °C are assumed to be related to the variation in cation distribution accompanying the disproportionation of Mn ions. 相似文献
97.
Shingo Hadano Kenjiro Onimura Hiromori Tsutsumi Hirohito Yamasaki Tsutomu Oishi 《应用聚合物科学杂志》2003,90(8):2059-2065
Chemical‐modified pulps were synthesized from four types of waste pulps (Pulp1–4) and succinic anhydride (SAn) or maleic anhydride (MAn). The solubility of the modified pulps was evaluated in common organic solvents, and their thermal properties were investigated by DSC measurement. The solubility of the modified pulps increased with an increasing degree of substitution (DS). However, no Tg or Tm of these modified pulps was confirmed. Pulps and modified pulps were graft‐polymerized with ε‐caprolactone (CL) in bulk and in DMAc/LiCl. Although the solubility of the graft copolymers was similar to modified pulps, some graft copolymers showed a Tg by the introduction of CL units. In the bulk, graft copolymers obtained from modified pulps and nonmodified pulps showed a Tg of about 75°C and no Tg, respectively. In DMAc/LiCl, the obtained graft copolymers from both modified and nonmodified pulps exhibited a Tg of 95–110°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2059–2065, 2003 相似文献
98.
Yuki Yamaguchi Yoshihiro Kanamaru Minori Fukushima Kenjiro Fujimoto Shigeru Ito 《Journal of the American Ceramic Society》2015,98(10):3054-3061
Highly crystallized fine powder of strontium titanate (SrTiO3) was obtained at room temperature simply by leaving a vial containing the powder mixture of Sr(OH)2·8H2O and hydrous titania gel (TiO2·nH2O) for 10 d. Solvent and additive(s) used in the conventional low‐temperature process were not used. The crystallinity judged from the FWHM of X‐ray diffraction peak was comparable to that obtained by a solid‐state reaction. To cause the reaction at room temperature, the titania gel had to contain a considerable amount of H2O (n > 0.97). The reaction is considered to be neutralization of titanic acid [H4TiO4 or Ti(OH)4] and strontium hydroxide (base). Using similar process, highly crystallized BaTiO3 powder was also obtained at 60°C. In comparison with the formation temperature of BaTiO3, tolerance factor in the perovskite structure was important for the room‐temperature synthesis of SrTiO3. SrTiO3 was hardly obtained at room temperature by the addition of saturated strontium hydroxide solution to the hydrous TiO2 gel (n = 1.29). Therefore, the reaction seems to proceed in the hydrous titania gel. This process is characterized by three important points; “no solvent”, “no additional reagents”, and above all, “no heating”. 相似文献
99.
Junichi Tatami Tomofumi Katashima Katsutoshi Komeya Takeshi Meguro Toru Wakihara 《Journal of the American Ceramic Society》2005,88(10):2889-2893
Carbon nanotube (CNT)-dispersed Si3 N4 ceramics with electrical conductivity were developed based on the lower temperature densification technique, in which the key point is the addition of both TiO2 and AlN as well as Y2 O3 and Al2 O3 as sintering aids. This new ceramic with a small amount of CNTs exhibits very high electrical conductivity in addition to high strength and toughness. Since Si3 N4 ceramics with Y2 O3 –Al2 O3 –TiO2 –AlN were originally used as a wear material, electrically conductive Si3 N4 ceramics are expected to be applied for high-performance static-electricity-free bearings for aerospace and other high-performance components. 相似文献
100.
Numerical plate testing for linear two‐scale analyses of composite plates with in‐plane periodicity 下载免费PDF全文
Kenjiro Terada Norio Hirayama Koji Yamamoto Mayu Muramatsu Seishiro Matsubara Shin‐nosuke Nishi 《International journal for numerical methods in engineering》2016,105(2):111-137
A method of numerical plate testing (NPT) for composite plates with in‐plane periodic heterogeneity is proposed. In the two‐scale boundary value problem, a thick plate model is employed at macroscale, while three‐dimensional solids are assumed at microscale. The NPT, which is nothing more or less than the homogenization analysis, is in fact a series of microscopic analyses on a unit cell that evaluates the macroscopic plate stiffnesses. The specific functional forms of microscopic displacements are originally presented so that the relationship between the macroscopic resultant stresses/moments and strains/curvatures to be consistent with the microscopic equilibrated state. In order to perform NPT by using general‐purpose FEM programs, we introduce control nodes to facilitate the multiple‐point constraints for in‐plane periodicity. Numerical examples are presented to verify that the proposed method of NPT reproduces the plate stiffnesses in classical plate and laminate theories. We also perform a series of homogenization, macroscopic, and localization analyses for an in‐plane heterogeneous composite plate to demonstrate the performance of the proposed method. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献