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排序方式: 共有189条查询结果,搜索用时 78 毫秒
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In this article we generalize the CM method for elliptic and hyperelliptic curves to Picard curves. We describe the algorithm in detail and discuss the results of our implementation.
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Annegret Tillack Harald Trauthwein Christian G. Hartung Martin Eichberger Stephan Pitter Achim Jansen Matthias Beller 《Monatshefte für Chemie / Chemical Monthly》2000,131(12):1327-1334
Summary. The oxidative amination of styrene with secondary amines in the presence of cationic rhodium catalysts yields regiospecifically
the corresponding anti-Markovnikov enamines. Styrene as the hydrogen acceptor gave concomitantly ethylbenzene. In the presence of 1,5-cyclooctadiene (cod) preferential reduction to cyclooctene takes place. The addition of cod reduces the rate of the reaction, but also the amount of ethylbenzene produced. Here, for the first time the ratio of enamine:
ethylbenzene is > 1, which is favourable in case of more expensive styrene derivatives. A screening of various ligands for
oxidative amination reveals that hemilabile 2-(ω-phosphino-n-alkyl)-pyridines are superior ligands for this reaction compared to simple alkyl and aryl phosphines.
Received May 30, 2000. Accepted July 11, 2000 相似文献
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Triphilic Ionic‐Liquid Mixtures: Fluorinated and Non‐fluorinated Aprotic Ionic‐Liquid Mixtures
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Dr. Oldamur Hollóczki Dr. Marina Macchiagodena Henry Weber Martin Thomas Dr. Martin Brehm Prof. Dr. Annegret Stark Dr. Olga Russina Dr. Alessandro Triolo Prof. Dr. Barbara Kirchner 《Chemphyschem》2015,16(15):3325-3333
We present here the possibility of forming triphilic mixtures from alkyl‐ and fluoroalkylimidazolium ionic liquids, thus, macroscopically homogeneous mixtures for which instead of the often observed two domains—polar and nonpolar—three stable microphases are present: polar, lipophilic, and fluorous ones. The fluorinated side chains of the cations indeed self‐associate and form domains that are segregated from those of the polar and alkyl domains. To enable miscibility, despite the generally preferred macroscopic separation between fluorous and alkyl moieties, the importance of strong hydrogen bonding is shown. As the long‐range structure in the alkyl and fluoroalkyl domains is dependent on the composition of the liquid, we propose that the heterogeneous, triphilic structure can be easily tuned by the molar ratio of the components. We believe that further development may allow the design of switchable, smart liquids that change their properties in a predictable way according to their composition or even their environment. 相似文献
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We consider a p(x)-Laplace thermistor model for electrothermal effects in organic semiconductor devices and propose a hybrid finite-volume/finite-element scheme which is combined with path-following methods to find a numerical solution. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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