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31.
Tetsuya Tanigami Nobuyuki Maruyama Koji Yamazaki Yoko Ichikawa Hiroyuki Nagai Kaori Shimizu 《应用聚合物科学杂志》2002,86(7):1807-1815
An almost fully saponified atactic poly(vinyl alcohol) and an atactic poly(vinyl alcohol‐block‐vinyl acetate) of which degree of saponification is 89 mol % were blended by a solution casting method. The phase structure of the blend film was analyzed by optical microscopy, 13C‐NMR, and differential scanning calorimetry. The most remarkable structure of the blend was composed of cylindrical domains penetrating the film. The swelling behavior of the blend films was also investigated in the dimethylsulfoxide and water mixed solvents to find differences in solubility and diffusion behavior between the matrix and the domain. The cylindrical domains could be selectively dissolved away in water and the film became porous. We tried to change the size of the cylindrical domain with various film preparation conditions. This aimed to turn the film into the useful filter membrane. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1807–1815, 2002 相似文献
32.
Akira Kishimoto Ginjiro Toyoguchi Hiroshi Ichikawa 《Journal of the American Ceramic Society》2002,85(2):479-480
Piezoresistivity effect of a silicon carbide-based ceramic fiber (Nicalon family) was evaluated when a single fiber was buried at the tensile plane in a plastic rectangular bar subjected to bending to apply a stable tensile strain. Electrical resistivity change during the bending was monitored by a digital high-resistance meter. From the fracture strain, Young's modulus, and the resistivity change, the piezoresistance coefficient is calculated to be 1.6 × 10−11 m2 /N, which is in agreement with the reported value for silicon carbide single crystals and our own reported value for polycrystalline silicon carbide ceramics. 相似文献
33.
Jooho Moon Masanobu Awano Kunihiro Maeda 《Journal of the American Ceramic Society》2001,84(11):2531-2536
Well-defined La2 Sn2 O7 with a phase-pure pyrochlore structure was produced by hydrothermal synthesis at temperatures as low as 200°C. Production of phase-pure La2 Sn2 O7 requires a pH above 10, and higher pH accelerates the crystallization process. The synthesis produced spherical particles of average particle size ∼0.59 μm (±0.12) and surface area ∼14.1 m2 /g. SEM and TEM observation for morphologic evolution and kinetic analysis during crystallization indicated that La2 Sn2 O7 formation probably proceeds via a two-step reaction. First a transient dissolution–precipitation occurs. Then the primary crystallites aggregate because of their colloidal instability, and heterocoagulation with the lanthanum hydrous oxide precursor particles also occurs. The sluggish reaction rate at the later stage of reaction is characterized by an in situ transformation, where the soluble tin species is diffused through the porous La2 Sn2 O7 aggregates to react with entrapped lanthanum precursors. 相似文献
34.
Tomoko Okuyama Jun Shirakawa Kazuki Tajima Yoko Ino Heidrun Vethe Yu Togashi Mayu Kyohara Ryota Inoue Daisuke Miyashita Jinghe Li Nozomi Goto Taiga Ichikawa Shingo Yamasaki Haruka Ohnuma Rie Takayanagi Yayoi Kimura Hisashi Hirano Yasuo Terauchi 《International journal of molecular sciences》2020,21(21)
35.
Photoelectric properties of ABA‐type triblock copolymers designed using fluorine‐containing polyimide macroinitiators with polyhedral oligomeric silsesquioxane 下载免费PDF全文
Shuichi Sato Masato Ichikawa Erika Suzuki Hironaga Matsumoto Kazukiyo Nagai 《Polymer Engineering and Science》2017,57(11):1207-1213
4,4′‐(Hexafluoro‐isopropylidene) diphthalic anhydride‐2,3,5,6‐tetramethyl‐1,4‐phenylenediamine (6FDA‐TeMPD) was synthesized and reacted with polyhedral oligomeric silsesquioxane (POSS) to form an ABA‐type triblock copolymer by atom transfer radical polymerization. The solid‐state and optical properties of the resulting copolymers were systematically investigated, and their electronic states were analyzed. As the POSS concentration increased, the transparency across the entire wavelength range increased. In the ABA‐type triblock copolymers, a new transition was observed between the highest occupied molecular orbital in POSS and the lowest unoccupied molecular orbital in 6FDA‐TeMPD because of their high molecular size dispersion. Since the refractive index of 6FDA‐TeMPD decreased linearly as the POSS concentration increased, the refractive index of the ABA‐type triblock copolymers of 6FDA‐TeMPD with POSS could be easily controlled. POLYM. ENG. SCI., 57:1207–1213, 2017. © 2017 Society of Plastics Engineers 相似文献
36.
Sun-Chan Jeong Ichiro Katayama Hirokane Kawakami Yutaka Watanabe Hironobu Ishiyama Nobuaki Imai Yoshikazu Hirayama Hiroari Miyatake Masao Sataka Satoru Okayasu Hiroyuki Sugai Shin-Ichi Ichikawa Katsuhisa Nishio Shinichi Mitsuoka Takamitsu Nakanoya Masahito Yahagi Takanori Hashimoto Kazunori Takada Mamoru Watanabe Tomoko Ishikawa Akihiro Iwase 《Journal of Phase Equilibria and Diffusion》2005,26(5):472-476
For the effective use of short-lived radioactive beams, soon to be available at the Tokai Radioactive Ion Accelerator Complex, the authors have developed a radiotracer method for diffusion studies in solids. The experimental test was performed by the measurement of the diffusion coefficients of Li in a sample of the compound βLiAl using an α-emitting radiotracer of 8Li (T1/2=0.84 s). It was found that the time-dependent yields of the α particles from the diffusing 8Li that was initially implanted in the sample could be used as a measure of the diffusivity of the tracer in a nondestructive way. The method was applied to measure the self-diffusion coefficients of Li in βLiGa, and for investigating how the Li diffusion in the Li ionic conductors is affected by the concentration of atomic defects (i.e., the existence of the atomic vacancies of Li and the defects in Ga sites that are replaced by Li). 相似文献
37.
The stannous ion consumption in methane sulfonic acid (MSA) baths with and without catechol was quantitatively evaluated using platinum and IrO2–Ta2O5/Ti anodes. The stannous ion is consumed at the same rate with both anodes, accompanied by the generation of tin sludge on the anode surfaces in the bath without catechol, while these undesirable phenomena are significantly suppressed in the bath containing catechol. Spectroscopic measurements indicate that stannous ion and catechol form a complex at the mole ratio of 1:2, thus preventing the oxidation of stannous ions. This complexation effect is independent of the anode material at low current density, but depends on the anode material at high current density. The stannous ion consumption at high current density is sufficiently inhibited only with the IrO2–Ta2O5/Ti anode due to the low oxygen evolution potential. Voltammetric measurements also suggest that the continuous oxidation of stannous ion in the catechol-containing bath is simultaneous with oxygen evolution. 相似文献
38.
Michio Takeda Akinori Saeki Jun-ichi Sakamoto Yoshikazu Imai Hiroshi Ichikawa 《Journal of the American Ceramic Society》2000,83(5):1063-1069
SiC-based fibers with various chemical compositions were synthesized using an irradiation-curing process. Polycarbosilane (PCS) fibers were cured by irradiation with an electron beam in a helium atmosphere. The cured PCS fibers were pyrolyzed at 1300°C under controlled hydrogen or argon atmospheres, and SiC fibers with C/Si of 0.84 to 1.56 were obtained. The fibers consisted of <1.0 wt% O, <0.2 wt% N, <0.1 wt% H, with the balance being Si and C. The mechanism of pyrolytic transformation of cured PCS to SiC-based ceramics was investigated using TG/DTA analysis. Greater mass losses were observed during pyrolysis in a hydrogen atmosphere than in argon. This result suggests that the hydrogen atmosphere suppresses H2 evolution and helps to remove excess carbon as CH4 during pyrolysis. The microstructure and mechanical properties of the resulting SiC-based fibers were found to be very dependent on their C/Si chemical compositions. 相似文献
39.
An inhibitor of human tyrosinase activity in rum distillate wastewater was isolated and identified as (S)-(+)-imperanene (1). (S)-(+)-Imperanene significantly inhibited tyrosinase isolated from HMV-II cells (IC(50) 1.85 mM). Inhibition kinetics studies revealed that imperanene is a competitive inhibitor of tyrosinase when L-3,4-dihydroxyphenylalanine is used as the substrate. The inhibitory activities of 1, O-beta-D-glucopyranosyl imperanene (2) and O-beta-D-glucopyranosyl-3-methoxyl imperanene (3) were 1>2>3. 相似文献
40.
The distribution behavior of n-alcohols, ketones and nitroalkanes in aqueous liquid chromatography with a column packed with polyethylene glycol (PEG) gel, TSKgel Ether-250, was compared with that in aqueous two-phase systems (ATPSs) formed from PEG and Na2SO4 or (NH4)2SO4. The plots of the distribution data obtained for the PEG gel system against those for the ATPS reveal that the separation selectivities exerted by the PEG gel system and the PEG-based ATPS are approximately the same. Differential scanning calorimetry studies on aqueous PEG solutions suggest that PEG polymer forms a hydration structure of which the composition is 50% (w/w) PEG or the hydration number per ethylene oxide is 2.4 and the separation selectivity of the PEG-water systems can be attributed to partition of solute compounds into the hydrated PEG polymer structure. 相似文献