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991.
Takahama Ryo Kato Honami Takayama Go Tajima Kenji Kondo Tetsuo 《Cellulose (London, England)》2022,29(6):3239-3251
Cellulose - BC membranes (pellicles) generated by Gluconacetobacter hansenii (G. hansenii) are promising biomaterials owing to their outstanding biocompatible properties. Recently, specific demands... 相似文献
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Ryo Takano Tomomi Nagai Xiaofen Wu Xin-Yan Xu Nguyen Tien Huy Kaeko Kamei 《Journal of carbohydrate chemistry》2013,32(9):1185-1190
ABSTRACT The polysaccharides, curdlan, starch and dextran were sulfated when heated in DMSO with sodium methyl sulfate and a catalytic amount of H2SO4 or with pyridinium methyl sulfate. Use of diminished pressure and anhydrous CaSO4 as a desiccant improved the degree of sulfation and recovery. Under conditions using sodium methyl sulfate, H2SO4 and CaSO4 in vacuo, sulfation at O-6 was predominant in the cases of curdlan and starch, while sulfation at O-2 and O-3 was preferential in the case of dextran. 相似文献
995.
Chiral phosphoramidite ligands prepared from (S)-binaphthol and various secondary amines were examined for the palladium-catalyzed asymmetric hydrosilylation of cyclohexa-1,3-diene with trichlorosilane. With a sterically demanding phosphoramidite bearing bis(diphenylmethyl)amine, the high enantiomeric excess of 87% was achieved, which is the highest enantioselectivity in the hydrosilylation of cyclohexadiene reported to date. The catalytic activity in the present hydrosilylation was high with all of the ligands employed, while the enantioselectivities varied dramatically depending on the dialkylamine moiety of the phosphoramidite ligand. 相似文献
996.
A practical preparation of chiral keto-imine type ONO Schiff base ligands has been reported. Metal complexes of these Schiff bases work as efficient chiral catalysts in a variety of asymmetric reactions. 相似文献
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Yuushou Nakayama Takamichi Inaba Yosuke Toda Ryo Tanaka Zhengguo Cai Takeshi Shiono Hiroyuki Shirahama Chikara Tsutsumi 《Journal of polymer science. Part A, Polymer chemistry》2013,51(20):4423-4428
l ‐Lactide (l ‐LA) was polymerized in the presence of N‐methyldiethanolamine as an initiator and Sn(Oct)2 as a catalyst to give hydroxy‐telechelic poly(l ‐lactide) (PLLA‐diol) bearing a tertiary amine group at the center of the polymer chain. Successive chain extension of the PLLA‐diol with hexamethylene diisocyanate afforded PLLA‐based poly(ester‐urethane)s (PEU) with equally spaced tertiary amine groups. Treatment of the PEU with iodomethane converted tertiary amine groups to quaternary ammonium groups to give cationic ionomers (PEU‐MeI). The thermal, mechanical, hydrophilic, and biodegradation properties of the obtained polymers were investigated. The thermal properties of the PEUs and the PEU‐MeIs were similar each other. The PEU‐MeIs exhibited higher tensile modulus than those of the starting PEUs. The contact angles of water on the PEU‐MeIs were lower than those of the PEUs with similar NMDA content indicating their higher hydrophilicity. In compost degradation tests, the PEU‐MeIs showed slower degradation than those of the PEUs. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4423–4428 相似文献
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We have tested and compared several (pseudo) random number generators (RNGs) applied to a practical application, ground state energy calculations of molecules using variational and diffusion Monte Carlo metheds. A new multiple recursive generator with 8th‐order recursion (MRG8) and the Mersenne twister generator (MT19937) are tested and compared with the RANLUX generator with five luxury levels (RANLUX‐[0–4]). Both MRG8 and MT19937 are proven to give the same total energy as that evaluated with RANLUX‐4 (highest luxury level) within the statistical error bars with less computational cost to generate the sequence. We also tested the notorious implementation of linear congruential generator (LCG), RANDU, for comparison. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010 相似文献
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