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141.
Shinji Sugihara Shin‐Ichiro Matsuzono Hideki Sakai Masahiko Abe Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2001,39(18):3190-3197
Amphiphilic diblock copolymers were prepared by the living cationic polymerization of vinyl ethers in the presence of added bases, and their selective solvent‐induced physical gelation behavior was investigated. The block copolymerization of 2‐phenoxyethyl vinyl ether (PhOVE) and 2‐methoxyethyl vinyl ether (MOVE) was carried out in the presence of ethyl acetate with Et1.5AlCl1.5 in toluene at 0 °C. Despite the rate difference, diblock copolymers with a very narrow molecular weight distribution were obtained, quantitatively. By adding the selective solvent, water, to the acetone solution of the diblock copolymer, PhOVE200‐b‐MOVE400, physical gelation occurred suddenly and the system ceased to flow, maintaining transparency. Viscoelastic measurements and transmission electron microscopic observations were performed to examine the characteristic gelation behavior and structure of the obtained gels. Various gelation conditions and physical gelation by other amphiphilic block copolymers were also designed on the basis of the solubility of each block segment. Further, new forms of physical gelation, accompanied by the solubilization of immiscible organic compounds, were achieved using similar diblock copolymers. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3190–3197, 2001 相似文献
142.
Kawashima Natsumi Kitazaki Tomoya Nogo Kosuke Nishiyama Akira Wada Kenji Ishimaru Ichiro 《Optical Review》2020,27(6):530-541
Optical Review - We propose a superimposing interferogram method to enhance the sensitivity and interference definition of spatial-phase-shift interferometers. The proposed method uses a multi-slit... 相似文献
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Ichiro Ohba 《Foundations of Physics》1997,27(12):1725-1738
A novel method to quantize systems of damped motion is proposed in the frameworks of canonical quantization and path integral
quantization. It can be afforded by considering a Lagrangian multiplied by a time-dependent function, which may represent
an effective interaction with “environment.” 相似文献
145.
Tsuneo Itoh Ikuko Fujii Yasuo Tomii Ichiro Ishikawa Hamo Ogura Yoshihisa Mizuno Norio Kawahara 《Journal of heterocyclic chemistry》1987,24(5):1453-1455
An improved and efficient synthesis of 1,3-dialkylpyrido[2,3-d]pyrimidine-2,4-(1H,3H)-diones from 6-methylaminouracils and methyl propiolate or diethyl ethoxymethylenemalonate is described. 相似文献
146.
Yasuhasru Kihira Hitoshi Yamamura Ichiro Murakami 《Journal of Polymer Science.Polymer Physics》1986,24(4):867-876
Dielectric and infrared data have been obtained over a wide temperature range on copolymers of ethyl methacrylate with methacrylic and acrylic acid synthesized by radical copolymerization. The dissociation energy ΔH0 for the acid dimer in the copolymer is estimated from the temperature dependence of the relaxation strength Δεα of the α relaxation, which is associated with the glass transition. The value of δH0 obtained by this method is in fair agreement with that determined by infrared (IR) spectroscopy. The strength of the α relaxation and its activation energy are both increased by the incorporation of methacrylic acid units but are decreased by acrylic acid units. This behavior is attributed to the restriction of main-chain motions by hydrogen-bonded acid dimers in the copolymers with methacrylic acid and to the incorporation of more flexible links in the copolymers with acrylic acid. The β relaxation observed below the glass transition temperatures is almost unaffected by the incorporation of methacrylic acid. 相似文献
147.
Ichiro Miyada 《manuscripta mathematica》1995,88(1):535-540
We show that there exist only finitely many imaginary abelian number fields of type (2,2,...,2) with one class in each genus.
Moreover, if the Generalized Riemann Hypothesis is true, we have exactly 301 such fields, whose degrees are less than or equal
to 23. Finally we give the table of those 301 fields. 相似文献
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Recently the double-minimum potentials for the pyramidal distortion in the S1(n,π*) state of a number of aliphatic carbonyl compounds like acetaldehyde, acetone and cyclic ketones have been determined using the supersonic nozzle beam technique We have found a good correlation between the barrier height to inversion and the angle between the two bonds adjacent to the carbonyl carbon atom. In order to elucidate the correlation in more detail, we performed ab initio calculations for the S1 state of formaldehyde with the HCH angle as a parameter. The SCFCI calculation verified the observed correlation. It is postulated that the barrier height can be correlated with a single geometric parameter, the HCH angle. 相似文献