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Masanao Oya Keikichi Uno Yoshio Iwakura 《Journal of polymer science. Part A, Polymer chemistry》1972,10(2):613-623
Copolymerization of NCA's was undertaken in a heterogeneous system in acetonitrile, which is not a solvent of the polypeptides. The reactivity ratio was calculated by using the Lewis-Mayo equation. Further, the conversion rate in the copolymerization and the configuration of the copolymer produced were compared with those of the copolymerization in the homogeneous system in nitrobenzene, in which the copolypeptides are swollen. The rate of copolymerization in acetonitrile was between the rates of polymerization of the individual monomers. It has been reported that the configuration of the copolymer obtained in dimethylformamide, in which the copolypeptides are swollen, is of the block type. On the other hand, many polypeptides obtained in acetonitrile, which is not a solvent of the copolypeptides, had a random configuration near to an alternating configuration. 相似文献
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Kawasaki T Nonaka Y Watanabe K Ogawa A Higuchi K Terashima R Masuda K Sakamoto M 《The Journal of organic chemistry》2001,66(4):1200-1204
The reverse aromatic Cope rearrangement of 2-allyl-3-alkylideneindolines obtained by Horner-Wadsworth-Emmons olefination of 2-allylindolin-3-ones was performed. When 2-allylindolin-3-ones were treated with phosphonium ylides in refluxing toluene, domino Wittig reaction and reverse aromatic Cope rearrangement took place to give alpha-allyl-3-indole acetate derivatives in good yields. The aromatization as a new driving force in the Cope rearrangement is preferable to the conjugation with the carbonyl and cyano groups and also to the alkyl substitution pattern, which are well-known driving forces. 相似文献
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In the presence of trifluoroacetic acid, N-phenyl-N′-phenoxyurea (1a) rearranges to N-(4′-hydroxy-2-biphenylyl)urea (2a) and N-carbamoyl-2-hydroxy-diphenylamine (3a). The rearrangement is an intramolecular reaction, and the transition state of the breakage of the N-O bond is deduced to be polarized in the form Nδ- --- Oδ+. The reaction is entirely new and constitutes a fundamental aromatic rearrangement. 相似文献
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Norio Manabe Kenichi Kawamura Masanao Ishikawa Shoutarou Suzuki Boping Liu Minoru Terano Hisayuki Nakatani 《Polymer Testing》2005,24(8):994-997
In this study, a novel potentiometric titration of hydroperoxide in degraded polypropylene (PP) is proposed. This titration is quite sensitive compared with the conventional ones such as UV and manual titrations, and its detection limit was about 2 meq/kg. The sensitivity was equal to that of molecular weight measurement by GPC for the degraded PP and, in addition, the volatilization behavior of the hydroperoxide could be detected. This titration was found to be very effective for the determination of PP degradation. 相似文献
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Oka H Suzuki M Harada K Iwaya M Fujii K Goto T Ito Y Matsumoto H Ito Y 《Journal of chromatography. A》2002,946(1-2):157-162
pH-Zone-refining counter-current chromatography was successfully applied to the separation of the main components of Food Color Red No. 106 (R-106, acid red, Color Index No. 45100). A 300-mg quantity of sample was separated using the following two-phase solvent system: n-butanol-water, 40 mM sulfuric acid in organic stationary phase and 30 mM ammonia in aqueous mobile phase. The obtained fractions were analyzed by high-performance liquid chromatography and fast atom bombardment mass spectrometry. The separation yielded 261.9 mg of main component of acid red with purity of 99.9%. 相似文献
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O. I. Lebedev † J. Verbeeck G. Van Tendeloo N. Hayashi T. Terashima M. Takano 《哲学杂志》2013,93(36):3825-3841
Thin films of SrFeO3??? x (0?≤?x?≤?0.5) (SFO) grown on a (LaAlO3)0.3 (SrAl0.5Ta0.5O3)0.7 (LSAT) substrate by pulsed laser deposition have been structurally investigated by electron diffraction and high resolution transmission electron microscopy for different post-deposition oxygen treatments. During the deposition and post-growth oxidation, the oxygen-reduced SFO films accept extra oxygen along the tetrahedral layers to minimize the elastic strain energy. The oxidation process stops at a concentration SFO2.875 and/or SFO2.75 because a zero misfit with the LSAT substrate is reached. A possible growth mechanism and phase transition mechanism are suggested. The non-oxidized films exhibit twin boundaries having a local perovskite-type structure with a nominal composition close to SFO3. 相似文献
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Li T Garg U Liu Y Marks R Nayak BK Rao PV Fujiwara M Hashimoto H Kawase K Nakanishi K Okumura S Yosoi M Itoh M Ichikawa M Matsuo R Terazono T Uchida M Kawabata T Akimune H Iwao Y Murakami T Sakaguchi H Terashima S Yasuda Y Zenihiro J Harakeh MN 《Physical review letters》2007,99(16):162503
The strength distributions of the giant monopole resonance (GMR) have been measured in the even-A Sn isotopes (A=112-124) with inelastic scattering of 400-MeV alpha particles in the angular range 0 degrees -8.5 degrees . We find that the experimentally observed GMR energies of the Sn isotopes are lower than the values predicted by theoretical calculations that reproduce the GMR energies in 208Pb and 90Zr very well. From the GMR data, a value of Ktau = -550 +/- 100 MeV is obtained for the asymmetry term in the nuclear incompressibility. 相似文献