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931.
Shuichi Matsumura Takeshi Okamoto Keisuke Tsukada Kazunobu Toshima 《Macromolecular rapid communications》1998,19(6):295-298
Oxiranes, such as glycidyl phenyl ether (GPE) and benzyl glycidate (BG), were copolymerized with succinic anhydride (SA) by lipase at a temperature between 60 and 80°C to yield the corresponding polyesters bearing carboxyl or phenyl groups. Bulk polymerization, especially at the temperature of 80°C, and preferably using porcine pancreatic lipase gave biodegradable polyesters with a molecular weight greater than 5000. 相似文献
932.
K. Feng M. Tsushima T. Matsumoto T. Kurosaki 《Journal of polymer science. Part A, Polymer chemistry》1998,36(5):685-693
Two chalcone-derivative isomers, 4,4′-diaminochalcone ( 4DAC ) and 3,3′-diaminochalcone ( 3DAC ), were synthesized and used as monomers together with tetracarboxylic dianhydrides to prepare novel photosensitive polyimides that contain a chalcone moiety in the main chain. The polyimides were characterized and their photochemical behavior was investigated as thin films and in solutions with the aid of ultraviolet and infrared spectroscopy. Compared with 4DAC -based polyimides, the 3DAC -based polyimides exhibited lower glass transition temperatures and higher photocrosslinking rates of the carbon–carbon double bond as well as higher photosensitivities obtained from the exposure characteristic curves, suggesting that an increase in the photoreactivity of the 3DAC -based polyimides might arise from the improved flexibility of their backbones. The polyimide from 3DAC and 6FDA (2,2-bis[3,4-dicarboxypheny]hexa-fluoropropane dianhydride) showed a photosensitivity of 33 mJ/cm2 with a contrast of 1.5 upon light irradiation using a Xenon lamp. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 685–693, 1998 相似文献
933.
934.
935.
Matsumoto Takashi Yamano Akihito Sato Takashi Ferrara Joseph D. White Fraser J. Meyer Mathias 《Journal of chemical crystallography》2021,51(3):438-450
Journal of Chemical Crystallography - The structure of organic compounds, including their absolute configuration, is extremely critical to the activity of medicines, aroma chemicals, and... 相似文献
936.
Takumi Mizuno Manabu Matsumoto Ikuzo Nishiguchi Tsuneaki Hirashima 《Heteroatom Chemistry》1993,4(5):455-458
Urea derivatives were readily synthesized in good yields under quite mild conditions, i.e., at ambient pressure and room temperature by sulfur-assisted carbonylation of primary amines with carbon monoxide followed by oxidation of the resulting ammonium thiocarbamates with molecular oxygen. 相似文献
937.
938.
K. Matsuda T. Matsumoto H. Saito K. Nishi T. Saiki 《Physica E: Low-dimensional Systems and Nanostructures》2000,7(3-4)
We study the variations of optical properties of self-assembled In0.5Ga0.5As single quantum dots (QDs) in the spatial and time domains by combining a near-field scanning optical microscope with an ultrafast pulsed laser. Through the examinations of several tens of QDs, we find that the variations of photoluminescence (PL) intensity strongly depend on the condition of the initial carrier creation. The differences in quantum efficiency and those in the carrier flow rate into QDs cause the large distribution of PL intensity when the carriers are excited in the barrier layers. From the results of time-resolved PL decay measurements, we find that there are two types of QDs exhibiting quite different PL decay profiles. 相似文献
939.
Moriguchi Isamu Tsujigo Yoshihiro Teraoka Yasutake Kagawa Shuichi 《Journal of Sol-Gel Science and Technology》2000,19(1-3):227-230
Synthesis of ZrO2 and hetero-layered TiO2/ZrO2 ultrathin films was investigated by two-dimensional sol-gel process assisted by n-octadecylacetoacetate (C18AA). When a hexane solution of tetrabutoxyzirconium (TBZ) and C18AA was spread on the water surface, Zr-based gel films stabilized with C18AA were formed at the air/water interface. After deposition on substrates, the gel films were successfully transformed into ZrO2 ultrathin films by heating at 773 K for 0.5 h, the thickness of which was controllable on the order of sub-nanometer level by the number of gel-layer deposition and the molar ratio of [TBZ]/[C18AA]. Well-organized hetero-multilayers composed of ultrathin TiO2 and ZrO2 layers could be fabricated by the alternate deposition of C18AA-stabilized Ti- and Zr-gel films. 相似文献
940.
M. Matsumoto C. E. McNamee D. P. Bossev M. Nakahara T. Ogawa 《Colloid and polymer science》2000,278(7):619-628
Tetraethylammonium perfluorooctyl sulfonate (TEAFOS; critical micelle concentration, 1 mM), which forms a threadlike micelle
in its pure solution, was adopted to study the structure of salted-out, solubilized micelles and microemulsions by cryogenic
transmission electron microscopy. The concentration of the surfactant was kept constant at 60 mM. The micelle solution salted
out with LiNO3 provided a surfactant phase in the presence of a clear interface. The surfactant phase was studded, being formed of homogeneously
dispersed spherical micelles, and had no obvious threadlike forms. The micelles, which solubilized the maximum amount of perfluorinated
oil, were spherical and had the same size as isolated spherical micelles in pure TEAFOS solution. The microemulsions were
formed in the presence of perfluorinated alcohol as cosurfactant and the particles were rotund even when the concentration
of the perfluorinated oil was equivalent to that for solubilization and the sizes increased with increasing oil content. The
difference in size between the solubilized micelles and microemulsions with the same amount of oil suggested that the oil
molecules had been solubilized between palisades of perfluorinated alkyl chains in the micelles and had dissolved in the cores
of the microemulsions.
Received: 10 September 1999/Accepted: 2 December 1999 相似文献