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Komoto, Shigeo*; Chuko, Tomotaka*; Hisamatsu, Shugo; Okuda, Yasuhiro*; Masu, Hyuma*; Takahashi, Masahiro*; Kishikawa, Keiki*
Crystal Growth & Design, 15(6), p.2723 - 2731, 2015/05
Times Cited Count:16 Percentile:75.03(Chemistry, Multidisciplinary)Piezoluminescence and liquid crystallinity of anthracene-based bispyridinium salts were investigated in stimulus responsive luminescent organic crystals and luminescent ionic liquid crystals. The salts possess an anthracene moiety as a fluorophore in their center, and the pyridiniums attached to the anthracene moiety are substituted with trialkoxybenzyl groups. Single crystals of the salts bearing two trimethoxybenzyl groups were obtained as solvates. Ethyl acetate, acetone, and dioxane solvates of the chlorides have almost the same crystal structures with one-dimensional channels. Grinding of the solvated crystals caused the extrusion of the included solvent molecules, which resulted in the red shifts of their fluorescence in the solid state. Tris(octyloxy)benzyl and tris(dodecyloxy)benzyl derivatives exhibited rectangular columnar liquid crystals upon being heated for their bromide and tetrafluoroborate salts and upon being cooled for their hexafluorophosphate salts.
Chimi, Yasuhiro; Iwase, Akihiro*; Ishikawa, Norito; Kobiyama, Mamoru*; Inami, Takashi*; Kambara, Tadashi*; Okuda, Shigeo*
Nuclear Instruments and Methods in Physics Research B, 245(1), p.171 - 175, 2006/04
Times Cited Count:16 Percentile:72.85(Instruments & Instrumentation)We have studied effects of irradiation with energetic particles on defect accumulation in nanocrystalline gold (nano-Au). The specimens of nano-Au foil (3-5 m thickness) with various grain sizes (23-156 nm) are prepared by the gas deposition method and subsequent thermal annealings. Irradiations of the specimens with 60-MeV C ions, 3.54-GeV Xe ions or 2.0-MeV electrons are performed at low temperature. The defect accumulation behavior is observed by measuring the electrical resistivity change during irradiation. Through an analysis of defect accumulation behavior, cross-sections for defect production, , and annihilation, , in nano-Au increase monotonically as the grain size decreases. These results are considered to be caused by the existence of a large volume fraction of the regions near grain boundaries in nano-Au where the threshold energy for atomic displacements, E, becomes lower than in polycrystalline gold. The possibility of electronic excitation effects in nano-Au is also discussed.
; Okuda, Takanari; ; ; Nomura, Shigeo; Shikakura, Sakae
Donen Giho, (75), p.59 - 63, 1990/09
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