In this article,we obtain the solutions of some fractional differential systems with different orders using the inverse operator method and Mittag–Leffler function.Moreover,the controllability of time-invariant linea...In this article,we obtain the solutions of some fractional differential systems with different orders using the inverse operator method and Mittag–Leffler function.Moreover,the controllability of time-invariant linear fractional system is investigated.Some examples are provided to illustrate the theory.展开更多
A novel porous and crystalline two-dimensional(2D)electrochemically active covalent organic framework(COF)based on ortho-quinone units has been prepared as an innovative approach towards the development of organic cat...A novel porous and crystalline two-dimensional(2D)electrochemically active covalent organic framework(COF)based on ortho-quinone units has been prepared as an innovative approach towards the development of organic cathode materials with multiple redox sites as an efficient electrocatalyst for the oxygen reduction reaction(ORR).In contrast with most of the previously reported COFs as electrocatalysts for the ORR,the electrocatalytic application of this material towards ORR has been investigated without adding any metal or conductive supporting material and avoiding any additional carbonization step.Additionally,the electrochemical properties of the COF material have been compared with two analogue amorphous frameworks with similar chemical composition,which points out the important role of the enhanced crystallinity and porosity of the COF network in its superior performance as an electrocatalyst towards ORR.展开更多
文摘In this article,we obtain the solutions of some fractional differential systems with different orders using the inverse operator method and Mittag–Leffler function.Moreover,the controllability of time-invariant linear fractional system is investigated.Some examples are provided to illustrate the theory.
基金This work was financially supported by MICINN(Nos.PID2019-106268GB-C33,CTQ2017-84309-C2-1-R,RED2018-102412-T,and FIS2017-82415-R)Comunidad Autónoma de Madrid Transnanoavansens Program(No.S2018/NMT-4349)。
文摘A novel porous and crystalline two-dimensional(2D)electrochemically active covalent organic framework(COF)based on ortho-quinone units has been prepared as an innovative approach towards the development of organic cathode materials with multiple redox sites as an efficient electrocatalyst for the oxygen reduction reaction(ORR).In contrast with most of the previously reported COFs as electrocatalysts for the ORR,the electrocatalytic application of this material towards ORR has been investigated without adding any metal or conductive supporting material and avoiding any additional carbonization step.Additionally,the electrochemical properties of the COF material have been compared with two analogue amorphous frameworks with similar chemical composition,which points out the important role of the enhanced crystallinity and porosity of the COF network in its superior performance as an electrocatalyst towards ORR.
