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51.
Masahiro Kurokawa Yuji Minoura 《Journal of polymer science. Part A, Polymer chemistry》1979,17(10):3297-3305
The copolymerizations of l-menthyl vinyl ether (l-MVE) with the monomers vinylene carbonate (VCA) and indene (IN) were carried out in benzene with azobisisobutyronitrile (AIBN) as an initiator to obtain optically active copolymers. The optically active l-menthyl residue from the copolymer main chain was removed using dry hydrogen bromide gas. After the ether cleavage reaction, the copolymers prepared (VA–VCA and VA–IN) were still optically active, and hence it was found that asymmetric induction had taken place in the copolymer main chain. The optical rotatory dispersion (ORD) and circular dichroism (CD) data of the original and ether-cloven copolymers were also determined. 相似文献
52.
Kazuhiro Watanabe Noboru Akino Tetsuo Aoyagi Noboru Ebisawa Yukio Fujiwara Atsusi Honda Takashi Inoue Takao Itoh Mikito Kawai Minoru Kazawa Junichi Koizumi Masaaki Kuriyama Kenji Miyamoto Naoki Miyamoto Kazuhiko Mogaki Yoshihiro Ohara Tokumichi Ohga Yoshikazu Okumura Hiroshi Oohara Katsumi Ohshima Fujio Satoh Kazuhiko Shimizu Syunji Takahashi Hirotsugu Usami Katsutomi Usui Masahiro Yamamoto Takeshi Yamazaki 《Radiation Physics and Chemistry》1997,49(6):631-639
A negative-ion-based neutral beam injector (N-NBI) has been constructed for JT-60U. The N-NBI is designed to inject 500 keV, 10 MW neutral beams using two ion sources, each producing a 500 keV, 22 A D− ion beam. In the preliminary experiment using one ion source, a D− ion beam of 13.5 A has been successfully accelerated with an energy of 400 keV (5.4 MW) for 0.12 s at an operating pressure of 0.22 Pa. This is the highest D− beam current and power in the world. Co-extracted electron current was effectively suppressed to the ratio of Ie/ID− < 1. The highest energy beam of 460 keV, 2.4 A, 0.44 s has also been obtained. To realize 1 MeV class NBI system for ITER (International Thermonuclear Experimental Reactor), demonstration of ampere class negative ion beam acceleration up to 1 MeV is an important mile stone. To achieve the mile stone, a prototype accelerator and a 1 MV, 1 A test facility called MeV Test Facility (MTF) were constructed. Up to now, an H− ion beam was accelerated up to the energy of 805 keV with an acceleration drain current of 150 mA for 1 s in a five stage electrostatic multi-aperture accelerator. 相似文献
53.
Masao Kato Yutaka Takemoto Yasuhiko Nakano Masahiro Yamazaki 《Journal of polymer science. Part A, Polymer chemistry》1975,13(8):1901-1910
Some unsaturated monomers bearing hindered phenol and arylamine groups capable of forming stable radicals were prepared. Radical polymerizations of vinyl monomers having such groups were investigated with the use of azobisisobutyronitrile, benzoyl peroxide, cumene hydroperoxide, and tetraethylthiuram disulfide as initiator. Polymerizations of these monomers went normally only when azobisisobutyronitrile was used as initiator. The other initiators inhibited polymerizations remarkably or completely. The results suggest that radicals resulting from benzoyl peroxide and cumene hydroperoxide or tetraethylthiuram disulfide abstract hydrogen of the phenol or the amine to produce the stable radicals, thereby inhibiting the polymerization. Meanwhile, carbon radicals resulting from azobisisobutyronitrile add selectively to the vinyl double bonds of the monomers to initiate the polymerizations. The vinyl derivatives as well as allyl derivatives and cinnamic acid derivatives copolymerize easily with conventional monomers such as styrene, maleic anhydride, and butadiene, again, only when azobisisobutyronitrile was used as initiator. Antioxidative properties for styrene copolymers and butadiene-styrene copolymers incorporating the hindered phenol monomers were investigated. 相似文献
54.
Dobashi T Nobe M Yoshihara H Yamamoto T Konno A 《Langmuir : the ACS journal of surfaces and colloids》2004,20(16):6530-6534
Curdlan dissolved in aqueous sodium hydroxide was dialyzed to aqueous calcium chloride to form a gel. Transparent and turbid concentric layers observed in the gel cross section perpendicular to the long axis of the dialysis tube were identified as liquid crystalline gels with refractive index gradient and amorphous gels, respectively. The thickness of each layer was proportional to the diameter of the dialysis tube, and the gelation proceeded in proportion to the root of time. The unique pattern formation was attributed to the change of curdlan conformation and calcium-induced cross-linking resulting from a diffusion of calcium cations and hydroxide anions through the dialysis tube. It is suggested that the orderedness of the curdlan molecules decreases by the increase of the curvature of the concentric liquid crystal layers as the layer comes toward the center of the dialysis tube. 相似文献
55.
56.
Synthesis of two naturally occurring 3-methyl-2,5-dihydro-1-benzoxepin carboxylic acids 总被引:1,自引:0,他引:1
[structures: see text] Two naturally occurring 3-methyl-2,5-dihydro-1-benzoxepin carboxylic acids, 6-hydroxy-3-methyl-8-(phenylethyl)-2,5-dihydro-1-benzoxepin-9-carboxylic acid (radulanin E) (1) and 9-hydroxy-3-methyl-2,5-dihydro-1-benzoxepin-7-carboxylic acid (2), were synthesized using Stille coupling followed by Mitsunobu cyclization. 相似文献
57.
The induced circular dichroism (ICD) spectra of the inclusion complexes of maleimide, phthalimide, and naphthalene‐2,3‐dicarboximide with β‐ or γ‐cyclodextrin (CDx) have been measured. The structure of the CDx inclusion complexes are interpreted by the signs and shapes of ICD spectra compared with the results of PPP calculations. In maleimide and naphthalene‐2,3‐dicarboximide, the ICD spectra of the β‐CDx inclusion complex are very similar to those of the γ‐CDx inclusion complex in spite of the differences in dimensions between the cavity of β‐CDx and that of γ‐CDx. In phthalimide, the ICD spectra of the β‐CDx inclusion complex are very different from those of the γ‐CDx inclusion complex. The split‐type ICD bands at 220–235 nm show that the dimer of phthalimide is formed in the presence of β‐CDx. 相似文献
58.
Novel Lewis-base ionic liquids replacing typical anions 总被引:1,自引:0,他引:1
Masahiro Yoshizawa-Fujita Katarina Johansson Douglas R. MacFarlane 《Tetrahedron letters》2006,47(16):2755-2758
We have synthesized two kinds of new Lewis-base ionic liquids (ILs); one is based on the relatively strong Lewis basic acetate anion, and the other is a salt composed of a mono-alkylated diamine such that the Lewis base site is incorporated in the cation. 1-Octyl-4-aza-1-azonia-bicyclo[2.2.2]octane bis(trifluoromethanesulfonyl)amide, [C8dabco]TFSA, and N-butyl-N-methylpyrrolidinium acetate, [p1,4]OAc, melted into fluid liquids at 26 and 81 °C, respectively. The thermal decomposition of [p1,4]OAc started at around 150 °C, whereas the thermal stability of [C8dabco]TFSA was almost equal to that of typical TFSA-based ILs in spite of the Lewis base site. This suggests that if the Lewis base site is incorporated into the cation the IL can maintain higher thermal stability. In addition, as a further result of the presence of the basic nitrogen, [C8dabco]TFSA can dissolve hydrated Cu(NO3)2 whereas the other TFSA-based ILs cannot. 相似文献
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