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Hopf代数同态与Hopf理想 被引量:1
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作者 任北上 《广西师范学院学报(自然科学版)》 2002年第4期23-26,共4页
利用Hopf代数的基本研究方法 ,讨论了在Hopf代数同态下有关商Hopf代数的性质并对余代数的基本同态定理进行了推广 .
关键词 HOPF代数 Hopf代数同态 Hopf理想 双代数 双理想 反极元
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Numerical Algorithm for Polarity Reversal Electric Field and Its Application 被引量:1
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作者 吕晓德 高本庆 《Journal of Beijing Institute of Technology》 EI CAS 1999年第2期50-55,共6页
Aim To analyze the transient speciality of nonlinear, anisotropic, AC+DC coupling electric field, and to compare the withstand voltage strength of different insulation structures. Methods The transient process o... Aim To analyze the transient speciality of nonlinear, anisotropic, AC+DC coupling electric field, and to compare the withstand voltage strength of different insulation structures. Methods The transient process of polarity reversal is analyzed, considering the anisotropic property of oil immersed press board, a new finite element model based on Galerkin method is presented and verified. The model developed is applied to calculate the electric field distribution in four typical winding end structures of the converter transformer. Results\ The whole ring structure possesses the best insulation characteristics. Conclusion\ By introducing reasonable insulation components, insulation strength with the same surrounding sizes can be improved more than 30%. 展开更多
关键词 ANISOTROPY finite element method polarity reversal INSULATION
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关于H—模余代数的余积分
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作者 任北上 《广西师院学报(自然科学版)》 1994年第2期15-20,共6页
对任意双代数H上的模余代数C,讨论了C的余积分性质和cocleft与反-cocleft之间的关系。
关键词 H-模余代数 余积分 反极元
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Enantioselective synthesis of mixed 3,3’-bisindoles via a phosphine-catalyzed umpolung γ-addition of 3’-indolyl-3-oxindoles to allenoates 被引量:1
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作者 Yildiz Tasdan Guang-Jian Mei Yixin Lu 《Science Bulletin》 SCIE EI CAS CSCD 2020年第7期557-563,M0004,共8页
An enantioselective umpolung γ-addition reaction of 3’-indolyl-3-oxindoles to allenoates catalyzed by amino acid-derived bifunctional phosphine catalysts has been developed. A wide range of chiral mixed 3,3’-bisind... An enantioselective umpolung γ-addition reaction of 3’-indolyl-3-oxindoles to allenoates catalyzed by amino acid-derived bifunctional phosphine catalysts has been developed. A wide range of chiral mixed 3,3’-bisindole scaffolds containing an all-carbon quaternary stereogenic center were obtained in high yields and with excellent enantioselectivities. 3,3’-Bisindoles are valuable synthetic intermediates, the employment of which led to formal total syntheses of(+)-Chimonanthine,(+)-Folicanthine and(-)-Calycanthine, as well as facile creation of useful pyrrolidinoindoline core structure. 展开更多
关键词 Umpolung c-addition Amino acid-derived bifunctional phosphine ALLENOATES Mixed 3 30-Bisindole Formal total syntheses
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