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991.
1st-5th generation poly(propyleneimine) dendrimers having peripheral 2,3-difluorobiphenyl mesogenic groups have been synthesized. They exhibited smectic liquid crystalline behaviour. All the liquid crystalline dendrimers exhibited a smectic A (SmA) phase and a crystal E (E) phase. The SmA-isotropic phase transition temperature increased with increasing generation. In addition, a homeotropic structure was spontaneously formed on a glass plate in the SmA phase for the 2nd, 3rd, and 4th generation dendrimers. The hometropic structure remained unchanged in the phase. 相似文献
992.
993.
994.
Motoo Tori Kaori Honda Yasuko Okamoto Shigeru Takaoka Yuemao Shen Ryo Hanai 《Tetrahedron》2006,62(20):4988-4995
Chemical constituents of root extract and the nucleotide sequences of the atpB-rbcL intergenic region and the internal transcribed spacers (ITSs) of the ribosomal RNA gene were studied for Ligularia virgaurea var. virgaurea collected in southwestern Sichuan Province of China. Eleven samples were collected. Four of them were found to contain four new furanoeremophilanes, virgaurenones A-D, as well as a new eremophilanolide, virgaurenolide A. The other samples contained different furanoeremophilanes and their derivatives including nor-type of compounds, two of which were new. Diversity was found to be present in the nucleotide sequences as well. The chemical composition was found to be correlated with the ITS variation but not with the geographic distribution of the samples. 相似文献
995.
The stereospecific exchange of a hydroxyl group of chiral alcohols bearing a pyridylseleno group on the adjacent carbon atom with aromatic compounds occurred smoothly in the presence of Lewis acid. 相似文献
996.
997.
998.
We shall present a couple of norm inequalities which will much improve the sharp triangle inequality with n elements and its reverse inequality in a Banach space shown recently by the last three authors. 相似文献
999.
Jian-guang Yang Sheng-hai Yang Takeshi Okamoto Takeshi Bessho Shigeru Satake Ryoichi Ichino Masazumi Okido 《Surface science》2006,600(24):L318-L320
Using aqueous–organic interface (water–oleic acid) reduction of Cu2+ by ascorbic acid, hydrophobic copper monolayer and copper particles have been prepared and characterized. The resultant monolayer could be transferred from the interface onto solid substrate or be dissolved to yield an organosol and copper nanoparticles. 相似文献
1000.
Takateru Kubota Chiyo Yamamoto Yoshio Okamoto 《Journal of polymer science. Part A, Polymer chemistry》2004,42(18):4704-4710
Three polysaccharide phenylcarbamate derivatives [cellulose 2,3-bis(3,5-dimethylphenylcarbamate)-6-(3,5-dimethylphenylcarbamate)/(2-methacryloyloxyethylcarbamate), cellulose 2,3-bis(3,5-dichlorophenylcarbamate)-6-(3,5-dichlorophenylcarbamate)/(2-methacryloyloxyethylcarbamate), and amylose 2,3-bis(3, 5-dimethylphenylcarbamate)-6-(3,5-dimethylphenylcarbamate)/(2-methacryloyloxyethylcarbamate)] with vinyl groups were prepared and coated onto silica gel to immobilize them via radical copolymerization with 2,3-dimethylbutadiene. The copolymerization efficiently proceeded, and the coated polysaccharide derivatives were mostly immobilized on the surface of the silica gel. The immobilized polysaccharide derivatives showed high chiral recognition abilities similar to those of the corresponding coated polysaccharide derivatives. They could be used with an eluent containing chloroform, which dissolved the polysaccharide derivatives. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4704–4710, 2004 相似文献