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排序方式: 共有266条查询结果,搜索用时 31 毫秒
21.
Yasutaka Takahashi Ayako Ohsugi Takeshi Arafuka Tomokazu Ohya Takayuki Ban Yutaka Ohya 《Journal of Sol-Gel Science and Technology》2000,17(3):227-238
The effects of several hydroxyketones such as acetol, actoin, -ketobutanol themselves and their combinations with monoethanolamine (MEA) or ethylenediamine (ED) on the stabilization of titanium tetraisopropoxide (TTIP) in isopropanol solution are examined. Acetoin itself and the imine derivatives of acetol and acetoin were found to show extraordinarily strong stabilizing effect for the alkoxide. The properties including the crystal modifications and refractive index of TiO2 films that were dip-coated using each stabilized solution are examined and discussed in comparison with those of the films obtained from the diethanolamine (DEA) systems. The effect of UV-light irradiation to the gel films on the crystallization of TiO2 is also examined and discussed. 相似文献
22.
Hideko T. Oyama Yoshikazu Tanaka Sakiko Hirai Shigenari Shida Ayako Kadosaka 《Journal of Polymer Science.Polymer Physics》2011,49(5):342-354
In this study, novel biodegradable materials were successfully generated, which have excellent mechanical properties in air during usage and storage, but whose structure easily disintegrates when immersed in water. The materials were prepared by melt blending poly(L ‐lactic acid) (PLLA) and poly(butylene adipate‐co‐terephthalate) (PBAT) with a small amount of oligomeric poly(aspartic acid‐co‐lactide) (PAL) as a degradation accelerator. The degradation behavior of the blends was investigated by immersing the blend films in phosphate‐buffered saline (pH = 7.3) at 40 °C. It was shown that the PAL content and composition significantly affected morphology, mechanical properties, and hydrolysis rate of the blends. It was observed that the blends containing PAL with higher molar ratios of L ‐lactyl [LA]/[Asp] had smaller PBAT domain size, showing better mechanical properties when compared with those containing PAL with lower molar ratios of [LA]/[Asp]. The degradation rates of both PLLA and PBAT components in the ternary blends simultaneously became higher for the blends containing PAL with higher molar ratios of [LA]/[Asp]. It was confirmed that the PLLA component and its decomposed materials efficiently catalyze the hydrolytic degradation of the PBAT component, but by contrast that the PBAT component and its decomposed materials do not catalyze the hydrolytic degradation of the PLLA component in the blends. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010 相似文献
23.
24.
Tetsutaro Kimachi Eri Torii Rina Ishimoto Ayako Sakue Motoharu Ju-ichi 《Tetrahedron: Asymmetry》2009,20(14):1683-1689
Starting from a reduced lapachol compound, the total synthesis of rhinacanthin A in both racemic and enantioenriched forms is achieved in eight steps without forming any undesired β-lapachone derivatives. For the synthesis of enantioenriched rhinacanthin A, the introduction of the asymmetric center was carried out by using the catalytic asymmetric epoxidation of an unfunctional trisubstituted olefin using Shi’s epoxidation diketal catalyst. The acidic treatment of a derived enantioenriched epoxynaphthol and the following CAN oxidation afforded the target molecule with high enantiomeric purity. 相似文献
25.
Yutaka Nagasawa Ayako Watanabe Yoshito Ando Tadashi Okada 《Journal of Molecular Liquids》2001,90(1-3):295-302
We have studied femtosecond ground state recovery dynamics of phenol blue (PB) by pump-probe spectroscopy with a time resolution of 33 fs. Multiexponential decay with time constants extending from 300 fs to 10 ps were observed. Some low frequency intramolecular quantum beats were also observed. Solvent dependence of these decays and beats are discussed. 相似文献
26.
As a chemiluminescent chemosensor that emits yellow light on reacting with a superoxide radical anion (O2−) and has a lipophilic character, a 6-phenylimidazo[1,2-a]pyrazin-3(7H)-one derivative possessing a boradiazaindacene (BODIPY) at the para position of 6-phenyl (1) was synthesized. The lipophilicity of 1 was investigated by reversed-phase liquid chromatography, and its log Pow value was found to be 3.57. This value was much higher than that of 2-methyl-6-(4-methoxypheyl)imidazo[1,2-a]pyrazin-3(7H)-one (MCLA, log Pow=1.19) and 6-[4-[2-{N′-(5-fluoresceinyl)thioureido}ethoxy]phenyl]-2-methylimidazo[1,2-a]pyrazin-3(7H)-one (FCLA, log Pow=−0.08), and it was comparable to that of benzenoid hydrocarbons. The O2−-induced chemiluminescence of 1 was investigated using the hypoxanthine/xanthine oxidase system as the source of O2−, and as a result, yellow emission was observed. The maximum wavelength was observed at 542 nm, and it was longer than that of FCLA. 相似文献
27.
The ruthenium(III) complex bearing phenylpyridine as a cyclometalated ligand serves as an efficient catalyst for the aerobic oxidative dehydrogenation of benzylamines to the corresponding benzonitriles under mild conditions. 相似文献
28.
Ayako Tokiwa Masayasu Nagoshi Yasuhiko Syono 《Physica C: Superconductivity and its Applications》1990,170(5-6):437-442
Superconductivity and composition analysis of PbBaSr(Y, Ca)Cu3Oy with fixed ratio of Sr/Ba = 1 were studied. Synthesis condition and superconductivity of Pb(Ba, Sr)2(Y, Ca)Cu3Oy with various ratio of Sr/Ba and Ca/Y were also studied. It was found that Tc increased with increasing Ca concentration, and that Sr-rich specimens allowed to contain more Ca. PbBa0.8Sr1.2Y0.6Ca0.4Cu3O7 showed superconductivity with zero-resistance temperature of 42 K, which was higher than PbBaSrY0.7Ca0.3Cu3O7 with maximum Ca content for Sr/Ba = 1. Decrease in averaged ionic radii of Ba and Sr in Sr-rich compositions would be favorable for the contraction of Cu-O bonds by hole-doping via Ca substitution for Y. 相似文献
29.
A sealed tube dry combustion method that is simple, accurate, and precise for ultramicro determination of halogens in organic compounds has been developed. Samples below 1 mg are heated at 580 °C for 1 h in an electric furnace. After the combustion and absorption of the gaseous halogen, the interior of the tube is rinsed. Subsequent titration is carried out potentiometrically with silver nitrate and yielded standard deviations of 0.21% for chlorine, 0.17% for bromine, and 0.25% for iodine. 相似文献
30.
Michio Zenki Makiko Ideshima Miwa Taniguchi Ayako Katoh Takashi Yokoyama 《Analytical sciences》2005,21(5):517-520
A circulatory flow-injection method (cyclic FIA) for the repetitive determination of zinc has been proposed. The procedure involves the use of 2-(5-bromo-2-pyridylazo)-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol (5-Br-PAPS) together with EDTA as a reagent carrier solution, which is recycled in a single-line flow system via a reservoir. The formed 5-Br-PAPS-Zn(II) complex was measured spectrophotometrically at 552 nm, and the signal intensity corresponded to the zinc concentration. After passing through a flow-through cell, the carrier stream then returned to the reservoir, and the main reagent, 5-Br-PAPS, was successfully regenerated by a ligand-exchange reaction with EDTA, allowing the repetitive determination of zinc. The calibration curve for zinc was linear in the concentration range from 0.4 to 10.0 mg dm(-3) with a correlation coefficient of 0.9995 (n = 6). The detection limit of this method was 0.02 mg dm(-3) (S/N= 3). This method allowed as many as 300 repetitive determinations of 2.0 mg dm(-3) zinc solution with only 100 cm3 of the circulating carrier solution, providing a reduction in the consumption of reagents and an elimination of waste, an important approach towards clean chemistry. 相似文献