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61.
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Akikazu Matsumoto Katsuhiko Fukushima Takayuki Otsu 《Journal of polymer science. Part A, Polymer chemistry》1991,29(12):1697-1706
Radical polymerization of N,N,N′,N′-tetraalkylfumaramides (TRFAm) bearing methyl, ethyl, n-propyl, isopropyl, and isobutyl groups as N-substituents (TMFAm, TEFAm, TnPFAm, TIPFAm, and TIBFAm, respectively) was investigated. In the polymerization of TEFAm initiated with 1,1′-azobiscyclohexane-1-carbonitrile (ACN) in benzene, the polymerization rate (Rp) was expressed as follows: Rp = k [ACN]0.28 [TEFAm]1.26, and the overall activation energy was 102.1 kJ/mol. The introduction of a bulky alkyl group into N-substituent of TRFAm decreased the Rp in the following order: TMFAm > TEFAm > TnPFAm > TIBFAm > TIPFAm ~ 0. The relative reactivities of these monomers were also investigated in radical copolymerization with styrene (St) and methyl methacrylate (MMA). In copolymerization of TRFAm (M2) with St (M1), monomer reactivity ratios were determined to be r1 = 1.07 and r2 = 0.20 for St–TMFAm, and r1 = 1.88 and r2 = 0.11 for St–TEFAm, from which Q2 and e2 values were estimated to be 0.35 and 0.44 for TMFAm, and 0.19 and 0.47 for TEFAm, respectively. The other TRFAm were also copolymerized with St, but copolymerization with MMA gave polymers containing a small amount of TRFAm units. The polymer from TRFAm consists of a less-flexible poly(N,N-dialkylaminocarbonylmethylene) structure. The solubility and thermal property of the polymers were also investigated. 相似文献
63.
多氮杂大环与许多金属离子能形成稳定的络合物。由于氮原子是三价的,因而多氮杂大环比冠醚具有更有利的结构;如果再导入羧基、膦酸基以及其他的亲水基团,则可得到一系列能形成水溶性金属络合物的配体。其中某些金属(如铜、钇等)的络合物在人体生理条件下表现出很好的稳定性,结合单原抗体技术的应用,这炎络合物在医疗、诊断方面有实用性。本文简单介绍某些代表性络合物的制备方法、物理性能和可能的应用。 相似文献
64.
T. Tsuchiya T. Sei Y. Watanabe M. Mori T. Kineri 《Journal of Sol-Gel Science and Technology》1997,8(1-3):685-688
Gold-dispersed BaTiO3, PGO and PLT thin films, which will be used for third-order nonlinear optical devices, were prepared by sol-gel process with
spin-coating using HAuCl44H2O, Ba(CH3COO)2, Ti[O(CH2)3CH3]4, Pb(CH3COO)23H2O, Ge[O-n-C4H9]4, La(CH3COO)31.5 H2O as starting materials. The thin films were heat-treated in air at temperatures ranging from 400 to 800 for 1 h. The nonlinear
optical property of these thin films was measured by the degenerate four-wave mixing (DFWM) method using a frequency-doubled
Nd: YAG laser with 20 ps pulse duration. Third-order nonlinear susceptibility χ(3) of gold-dispersed BaTiO3, PGO and PLT thin films with 5 vol% of gold were 1.410−6 esu, 3.510−7 esu respectively. The large χ(3) may be ascribed to the high dielectric constant of the films. 相似文献
65.
Dr. Yasunori Toda Takayuki Yoshida Kaoru Arisue Prof. Dr. Kazuaki Fukushima Dr. Hiroyoshi Esaki Ayaka Kikuchi Prof. Dr. Hiroyuki Suga 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(41):10578-10582
Chiral Lewis acid-catalyzed asymmetric alcohol addition reactions to cyclic carbonyl ylides generated from N-(α-diazocarbonyl)-2-oxazolidinones featuring a dual catalytic system are reported. Construction of a chiral quaternary heteroatom-substituted carbon center was accomplished in which the unique heterobicycles were obtained in good yields with high stereoselection. The alcohol adducts were successfully converted to optically active oxazolidine-2,4-diones by hydrolysis. Mechanistic studies by DFT calculations revealed that alcohols could be activated by Lewis acids, enabling enantioselective protonation of the carbonyl ylides. 相似文献
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Chun Gil PARK Jin Chuan HOU Sei Qwon OH 《数学学报(英文版)》2005,21(6):1391-1398
It is shown that every almost *-homomorphism h : A→B of a unital JC*-algebra A to a unital JC*-algebra B is a *-homomorphism when h(rx) = rh(x) (r 〉 1) for all x∈A, and that every almost linear mapping h : A→B is a *-homomorphism when h(2^nu o y) - h(2^nu) o h(y), h(3^nu o y) - h(3^nu) o h(y) or h(q^nu o y) = h(q^nu) o h(y) for all unitaries u ∈A, all y ∈A, and n = 0, 1,.... Here the numbers 2, 3, q depend on the functional equations given in the almost linear mappings. We prove that every almost *-homomorphism h : A→B of a unital Lie C*-algebra A to a unital Lie C*-algebra B is a *-homomorphism when h(rx) = rh(x) (r 〉 1) for all x ∈A. 相似文献
70.
Taniguchi J Yamaguchi A Ishimoto H Ikegami H Matsushita T Wada N Gatica SM Cole MW Ancilotto F Inagaki S Fukushima Y 《Physical review letters》2005,94(6):065301
Heat capacity measurements have been made down to 5 mK for 3He fluid films adsorbed in one-dimensional (1D) nanometer-scale pores, 28 A in diameter, preplated with 4He of 1.47 atomic layers. At low 3He density, the heat capacity shows a density-dependent, Schottky-like peak near 150 mK asymptoting to the value corresponding to a 2D Boltzmann gas at high temperatures. The peak behavior is attributed to the crossover from a 2D gas to a 1D state at low temperatures. The degenerate state of the 1D 3He fluid is indicated by a predominantly linear temperature dependence below about 30 mK. 相似文献