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491.
Yuki Sawa Yukio Tanaka Yasuhiro Asano 《Journal of Physics and Chemistry of Solids》2008,69(12):3247-3249
We study the Josephson effect in the superconductor/diffusive half metal/superconductor junctions by using the recursive Green function method. In the presence of spin-flip scatterings at the interface, odd-frequency spin-triplet Cooper pairs penetrate deeply into a half metal and carry Josephson current. The critical Josephson current increases with decreasing temperatures near the transition temperature. At low temperatures, however, the critical current decreases with decreasing temperatures. Such reentrant behavior is unusual in the case of s-wave superconductor junctions. The penetration of odd-frequency pairs modifies quasiparticle density of states in a half metal near the Fermi energy, which is responsible for the nonmonotonic temperature dependence of critical Josephson current. 相似文献
492.
Masaru Yoshida Masaharu Asano Takeshi Suwa Ryoichi Katakai 《Radiation Physics and Chemistry》1999,55(5-6):677-680
Swelling-controlled drug delivery copolymer gels were synthesized by introducing thermo- and pH-responsive methacryloyl-glycine (MA-Gly) of pH-responsive methacrylic acid (MA-Ac) into thermo-responsive acryloyl-
-proline ethyl ester (A-ProOEt). The threshold of swelling for copolymer gels consisting of A-ProOEt/MA-Gly and A-ProOEt/MA-Ac with a composition of 40/60 mol% was found to be pH 3.0 and pH 5.5, respectively, in buffer solutions at 37°C. The diffusion characteristics of 2-(3-benzoylphenyl)propionic acid (ketoprofen) from such copolymer gels were evaluated in buffer solutions at pHs more than 5.5, and it was found that A-ProOEt/MA-Gly gel possessed a Case II transport, while the A-ProOEt/MA-Ac gel exhibited a non-Fickian (or anomalous) diffusion behavior under the same conditions. 相似文献
493.
Atsushi Asano Masaru Eguchi Takuzo Kurotu 《Journal of Polymer Science.Polymer Physics》1999,37(16):2007-2012
Thermal dehydration process of PMAA was investigated by solid‐state 13C NMR. For heat‐treated PMAA at 150°C, at which the dehydration goes very slowly, we observed three 13C peaks at 172, 178, and 187 ppm in the carboxyl group region. The peak at 172 ppm is due to the intramolecular cyclic anhydrides by comparing the reported value of 13C chemical shift. The peaks at 178 and 187 ppm were assigned to regularly aligned free carboxylic acids and intermolecular acid dimers, respectively, from the 2D‐exchange 13C NMR spectra, 13C chemical shift values and IR spectra. We concluded that by heat‐treatment the rearrangement of intermolecular hydrogen bonding of the carboxylic acids in PMAA occurs firstly to form the regularly aligned acid dimers, and the dimers dissociated to be the regularly aligned free carboxylic acids at high temperatures. The adjacent free carboxyl acids dehydrate with each other, resulting in the formation of intramolecular anhydrides. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2007–2012, 1999 相似文献
494.
Akiko Asano Takeshi Yamada Atsushi Numata Mitsunobu Doi 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(9):o488-o490
The title compound, 1‐cyclohexylmethyl‐1‐de(1‐methylpropyl)ascidiacyclamide N,N‐dimethylacetamide dihydrate, C39H56N8O6S2·C4H9NO·2H2O, a cyclohexylalanine‐incorporated ascidiacyclamide analogue ([Cha]ASC), shows a square form similar to natural ASC. On the other hand, CD (circular dichroism) spectra showed [Cha]ASC to have a folded structure in solution, making it the second known analogue to show a discrepancy between its crystal and solution structures. Moreover, the cytotoxicity of [Cha]ASC (ED50 = 5.6 µg ml−1) was approximately two times stronger than that of natural ASC or a related phenylalanine‐incorporated analogue, viz. cyclo(‐Phe–Oxz–d ‐Val–Thz–Ile–Oxz–d ‐Val–Thz‐) ([Phe]ASC), and was confirmed to be associated with the square form. However, [Phe]ASC was previously shown to be folded in the crystal structure, which suggests that the difference between the aromatic and aliphatic rings affects the molecular folding of the ASC molecule. 相似文献
495.
Akiko Asano Mitsunobu Doi Kenji Yoza 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(6):o323-o325
Ceratospongamide (CS) is a potent inhibitor of secreted phospholipase A2, and cis,cis and trans,trans isomers, related with respect to the two proline amide bonds, are known. Crystals of cis,cis‐CS were grown from N,N‐dimethylacetamide solution, giving the title compound, the cyclic ester of isoleucyloxazolinylphenylalanylprolylthiazolylphenylalanylproline [cyclo(‐Ile–Oxz–Phe–Pro–Thz–Phe–Pro‐)] N,N‐dimethylacetamide hemisolvate, C41H49N7O6S·0.5C4H9NO. The structure is the third example of cis,cis‐CS to be investigated and comprises twinned crystals, in which the a and b axes are interchanged. The ratio of co‐existing twin crystals is approximately 50%. The peptide has a `saddle‐like' structure and is very similar to previously reported structures of cis,cis‐CS, which implies that the structure of cis,cis‐CS is very stable in spite of differences in crystallization conditions. 相似文献
496.
497.