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51.
Order - A modular semilattice is a semilattice generalization of a modular lattice. We establish a Birkhoff-type representation theorem for modular semilattices, which says that every modular... 相似文献
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Hidefumi Hirai 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(11):1491-1500
Terephthalic acid was synthesized by the carboxylation of benzoic acid with carbon tetrachloride in aqueous sodium hydroxide solution in the presence of cyclodextrin (CyD) and copper powder as catalyst. By the use of β-CyD at the initial molar ratio to benzoic acid of 0.5, the carboxylation at 60 °C for 7 hours produced terephthalic acid in 75 mol% yield with 87% selectivity. The selective synthesis of 4,4'-biphenyldicarboxylic acid in 70 mol% yield was achieved by the carboxylation of 4-biphenylcarboxylic acid with carbon tetrachloride in the presence of β-Cyd under similar conditions. The carboxylation of 2-naphthalene carboxylic acid with carbon tetrachloride using β-Cyd under similar conditions produced 2,6-naphthalenedicarboxylic acid in 67 mol% yield with 84% selectivity. When α-CyD and γ-CyD were used in place of β-Cyd, both the yields and the selectivities of the dicarboxylic acids were markedly small. In the absence of CyD, carboxylation did not proceed. Inclusion complex formations between β-Cyd and aromatic monocarboxylic acids were indicated by the 1H chemical shifts of the β-Cyd. The reaction mechanism was discussed on the basis of inclusion complex formation. 相似文献
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Noboru Oyama Takeo Ohsaka Fumihiro Yoshimura Masaya Mizunuma Shuichiro Yamaguchi Norihiko Ushizawa 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10-11):1463-1473
The electrode characteristics of ion-selective electrodes (ISEs) for K+, Na+, NH4 +, and Ca2+ based on bilayer film coatings, where the inner layer films are electroactive electropolymerized ones and the outer layer films are composed of conventional ion-sensitive materials, have been examined. These ISEs of the coated-wire electrode type have no conventional internal reference solution and reference electrode, but the inner films may be considered to function as the “internal standard solution.” The ion selectivity coefficients and the activity range showing Nernstian response were almost comparable to those of conventional liquid-membrane electrodes. The bilayer-coated ISEs showed insensitivity to O2 and CO2, long-term stability, and little drift. It was also found that the electrode performance is practically unchanged after sterilization in an autoclave. The results demonstrate that the bilayer-coated ISEs examined are promising for the determination of K+, Na+, NH4 +, or Ca2+ activity in biological and environmental systems. 相似文献
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Hidefumi Hirai 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(9-11):1293-1303
Macromolecule-copper(I) chloride complexes have been prepared for the separation of carbon monoxide and ethylene from gas mixtures with hydrogen, nitrogen, carbon dioxide, methane, and water. A toluene solution of a polystyrene-aluminum copper(I) chloride complex can separate carbon monoxide selectively and retains this function even on contact with gas containing water. Strong charge-transfer absorption bands have been found in the 380-500 nm region for the toluene solution of polystyrene-aluminum copper(I) chloride complex. A solution of 1, 3-diphenylpropane-aluminum copper(I) chloride complex also exhibits similar absorption bands. A continuous variation plot using the chemical shift change in 13C-NMR shows a 1:1 interaction between 1,3-diphenylpropane and aluminum copper(I) chloride. These results suggest a two-way interaction between the adjacent phenyl groups of polystyrene and aluminum copper(I) chloride. A resin bead of crosslinked polystyrene-aluminum copper(I) chloride complex has been prepared as a solid adsorbent. The water resistance of the solid macromolecular complex depends on the nature of the solvent used in the preparation of the solid adsorbent. Carbon disulfide is a suitable solvent. A selective adsorbent of ethylene has been prepared from a macroreticular polystyrene resin with primary and secondary amino groups and copper(I) chloride. The selectivity of ethylene against ethane and that of carbon monoxide against carbon dioxide increase with an increasing amount of supported copper(I) chloride. 相似文献
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Dr. Emi Uchida Dr. Kouji Sakaki Dr. Yumiko Nakamura Dr. Reiko Azumi Dr. Yuki Hirai Dr. Haruhisa Akiyama Dr. Masaru Yoshida Dr. Yasuo Norikane 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(51):17391-17397
Photoinduced phase transitions caused by photochromic reactions bring about a change in the state of matter at constant temperature. Herein, we report the photoinduced phase transitions of crystals of a photoresponsive macrocyclic compound bearing two azobenzene groups ( 1 ) at room temperature on irradiation with UV (365 nm) and visible (436 nm) light. The trans/trans isomer undergoes photoinduced phase transitions (crystal–isotropic phase–crystal) on UV light irradiation. The photochemically generated crystal exhibited reversible phase transitions between the crystal and the mesophase on UV and visible light irradiation. The molecular order of the randomly oriented crystals could be increased by irradiating with linearly polarized visible light, and the value of the order parameter was determined to be ?0.84. Heating enhances the thermal cis‐to‐trans isomerization and subsequent cooling returned crystals of the trans/trans isomer. 相似文献
57.
Hajime Yokoyama Takayoshi KuboYosuke Matsumura Junichi HosokawaMasahiro Miyazawa Yoshiro Hirai 《Tetrahedron》2014
The synthesis of indole skeleton by using Pd(II)-catalyzed cyclization of the urethane has been achieved. The urethanes with allylic alcohol were converted into vinyl indolines in good yield. The vinyl indoline was transformed into some intermediates of indole alkaloids. 相似文献
58.
A 405-nm diode laser has recently been developed for soft tissue problems in dentistry. A new in-office bleaching agent consisting of a titanium dioxide photocatalyst and 3.5% hydrogen peroxide has proven to react well with light irradiated at a wavelength of around 400 nm. In this study, we evaluated the bleaching efficacy of a newly developed 405-nm diode laser on bovine teeth treated with a bleaching agent composed of titanium dioxide and 3.5% hydrogen peroxide. Sixteen bovine incisors were randomly divided into two groups: Group A, irradiated by the 405-nm diode laser at 200 mW; Group B, irradiated by the 405-nm diode laser at 400 mW. The bleaching agent with titanium dioxide and 3.5% hydrogen peroxide was applied to bovine enamel and irradiated for 1 min. The specimens were then washed and dried, and the same procedure was repeated nine more times. After irradiation, we assessed the effects of bleaching on the enamel by measuring the color of the specimens with a spectrophotometer and examining the enamel surfaces with a scanning electron microscope. L* rose to a high score, reaching a significantly higher post-treatment level in comparison to pretreatment. In a comparison of the color difference (ΔE) between Group A and Group B, the specimens in Group B showed significantly higher values after 10 min of irradiation for the post-treatment. No remarkable differences in the enamel surface morphology were found between the unbleached and bleached enamel. The use of a 405-nm diode laser in combination with a bleaching agent of titanium dioxide and 3.5% hydrogen peroxide may be an effective method for bleaching teeth without the risk of tooth damage. 相似文献
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