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This article investigates the distributed optimization feedback control for a family of multi‐agent systems with external disturbances. For physical implementation in the scenario that only the sampled‐state information is available, a novel disturbance compensation distributed optimization control strategy is proposed by designing a sampled‐data‐based distributed protocol and a sampled‐data‐based disturbance compensator. The disturbances in the current sampling interval are compensated by an exact value at the time in the last sampling interval obtained by using the sampled data. It is proved that the states of agents converge to an arbitrarily small domain of the optimal point of the global cost function if the disturbances and their derivatives are bounded, and the sampling period is short enough. Besides, when disturbances are constants, all the agents' states converge to the optimal point asymptotically. Simulations consolidated the validity of the proposed method. [ABSTRACT FROM AUTHOR]

Despite considerable progress in the field of sustainable ammonia technology, the low efficiency and yield have remained the main bottleneck in artificial nitrogen fixation under ambient conditions. In this work, an ultrathin carbon quantum dot modified hydrogenated mesoporous SrTiO3 heterostructure (CQDs/STO) has been developed as a bifunctional catalyst for enhanced nitrogen reduction. CQDs/STO exhibits a high photocatalytic activity and an ammonia yield of 143 μmol g−1 h−1 has been achieved without any sacrificial reagent, which is about 7 times that of STO nanoparticles. Furthermore, we demonstrate that CQDs/STO can be utilized as a bifunctional catalyst for cascade photoelectrochemical nitrogen reduction, resulting in a ∼50% increase in the ammonia yield. DFT calculations reveal that the synergy between SrTiO3 and CQDs has the capability for photocatalytic reduction of N2 with the O-vacancies in SrTiO3 playing a key role also as electrocatalytic centers. We believe that such a cascade catalytic system provides a new insight into designing photoelectrochemical devices for solar-driven nitrogen fixation. [ABSTRACT FROM AUTHOR]

Summary: In this article, we develop a new nonlinear extended state observer (ESO) for output tracking of a class of uncertain nonlinear affine systems. Instead of using the linear functions of the error, the nonlinear functions of the properly magnified error are used in the proposed ESO. Compared with the linear ESO, the new ESO allows more accurate estimation and smaller peaking value. We also design an output‐feedback controller based on the proposed nonlinear ESO. The convergence of the new ESO is proved without assuming the boundedness of the system state. It is also proved that under the proposed output‐feedback controller, the system output is capable to track the given reference signal despite a large scope of nonlinear uncertainties. Simulation results illustrate the effectiveness of the new ESO with improved performance. [ABSTRACT FROM AUTHOR]