This article investigates the fully distributed observer-based adaptive fault-tolerant synchronization problem (SP) of multiagent systems with event-triggered control mechanisms. First, a nonlinear ...and discontinuous adaptive observer-based event-triggered fault-tolerant controller is proposed for each agent to overcome the occurrence of unknown faults and unmeasurable full states of the controlled system. Besides, an adaptive triggering function consisting of state-dependent and time-dependent threshold is developed to adjust the parameter of triggering threshold online. Then, a modified nonlinear and continuous observer-based controller with adaptive ETC strategy is developed to overcome the chattering phenomenon from the discontinuous controller. It is proved that under two controllers, the SP not only can be achieved in a fully distributed way without continuous communication for both the controller updates and the triggering condition detecting but also exclusion of "Zeno behavior" can be realized. Finally, the effective algorithms can be verified by giving numerical simulations related to mobile robots.
Multi‐resonance induced by boron and nitrogen atoms in opposite resonance positions endows a thermally activated delayed fluorescence (MR‐TADF) emitter with a strikingly small full width at half ...maximum of only 26 nm and excellent photoluminescence quantum yield of up to 97.48 %. The introduction of a carbazole unit in the para position of the B‐substituted phenyl‐ring can significantly boost up the resonance effect without compromising the color fidelity, subsequently enhancing the performances of the corresponding pure blue TADF‐OLED, with an outstanding external quantum efficiency (EQE) up to 32.1 % and low efficiency roll‐off, making it one of the best TADF‐OLEDs in the blue region to date. Furthermore, utilizing this material as host for a yellow phosphorescent emitter, the device also shows a significantly reduced turn‐on voltage of 3.2 V and an EQEmax of 22.2 %.
Strong enhancement of the multi‐resonance effect in thermally activated delayed fluorescence species by a peripheral carbazole unit substitution was applied for a material with a photoluminescent quantum yield of up to 97.48 %. The maximum luminance exceeded 16 000 cd m−2 and the highest external quantum efficiency was up to 32.1 %.
Circularly polarized organic light‐emitting diodes (CP‐OLEDs) are particularly favorable for the direct generation of CP light, and they demonstrate a promising application in 3D display. However, up ...to now, such CP devices have suffered from low brightness, insufficient efficiency, and serious efficiency roll‐off. In this study, a pair of octahydro‐binaphthol (OBN)‐based chiral emitting enantiomers, (R/S)‐OBN‐Cz, are developed by ingeniously merging a chiral source and a luminophore skeleton. These chirality–acceptor–donor (C–A–D)‐type and rod‐like compounds concurrently generate thermally activated delayed fluorescence with a small ΔEST of 0.037 eV, as well as a high photoluminescence quantum yield of 92% and intense circularly polarized photoluminescence with dissymmetry factors (|gPL|) of ≈2.0 × 10−3 in thin films. The CP‐OLEDs based on (R/S)‐OBN‐Cz enantiomers not only display obvious circularly polarized electroluminescence signals with a |gEL| of ≈2.0 × 10−3, but also exhibit superior efficiencies with maximum external quantum efficiency (EQEmax) up to 32.6% and extremely low efficiency roll‐off with an EQE of 30.6% at 5000 cd m−2, which are the best performances among the reported CP devices to date.
Octahydrobinaphthol‐compound‐based circularly polarized delayed fluorescence enantiomers, (R/S)‐OBN‐Cz are developed by merging a chiral source and a luminophore skeleton. The circularly polarized organic light‐emitting diodes based on (R/S)‐OBN‐Cz display intense CP‐electroluminescence signals with a |gEL| of ≈2.0 × 10−3, and achieve superior efficiencies with external quantum efficiency (EQE) up to 32.6% and extremely low efficiency roll‐off with an EQE of 30.6% at 5000 cd m−2.
Reported herein is an unprecedented synthesis of C3‐fluorinated oxindoles through cross‐dehydrogenative coupling of C(sp3)‐H and C(sp2)‐H bonds from malonate amides. Under the unique and mild ...electrochemical conditions, the requisite oxidant and base are generated in a continuous fashion, allowing the formation of the base‐ and heat‐sensitive 3‐fluorooxindoles in high efficiency with broad substrate scope. The synthetic usefulness of the electrochemical method is further highlighted by its easy scalability and the diverse transformations of the electrolysis product.
C−H functionalization: A ferrocene‐catalyzed electrochemical cross‐coupling reaction of C(sp3)‐H and C(sp2)‐H centers has been developed to give access to C3‐fluorinated oxindoles using fluorinated malonate amides. The electrosynthetic method is characterized by mild reaction conditions, broad substrate scope, high functional group tolerance, and easy scalability.
Graphdiyne (GDY) is regarded as an exceptional candidate to meet the growing demand in many fields due to its rich chemical bonds, highly π‐conjugated structure, uniformly distributed pores, large ...surface area, and high inhomogeneity of charge distribution. The extensive research efforts bring about a rapid expansion of GDY with a variety of functionalities, which significantly enhance performance including photocatalysis, energy, biomedicine, etc. In this review, the synthetic strategies (in situ and ex situ approaches) that are designed to rationally functionalize GDY, including optimizing their nanostructures by surface/interface engineering with dopants or functional groups (heteroatoms/small molecules/macromolecules), and building up hierarchical GDY‐based heterostructures are highlighted. Theoretical calculations on the structural evolution and electronic characteristics after the functionalization of GDY are briefly discussed. With elaborate functionalization and rational structure engineering, functional GDY applied in a variety of emerging applications (e.g., hydrogen evolution reaction, CO2 reduction reaction, nitrogen reduction reaction, energy storage and conversion, nanophotonics, sensors, biomedical applications, etc.) are comprehensively discussed. Finally, challenges and prospects concerning the future development of GDY‐based nanoarchitectures are also presented.
To exploit full potential and push the limits of graphdiyne (GDY), numerous functional GDY‐based nanoarchitectures are rationally designed with remarkably improved performances from both theoretical and experimental investigations. It is anticipated that this timely review can pave the way to new designs of functional GDY‐based nanoplatforms for next‐generation nanodevices.
This paper is concerned with security control of nonlinear unmanned marine vehicle (UMV) systems under a networked environment. The UMV system and land-based control station are connected by a ...communication network. Considering the limited communication resource in the marine environment, the dynamic event-triggering mechanisms are proposed in the sensor to controller and controller to actuator sides simultaneously. Meanwhile, the triggered output data is then quantized by a logarithmic quantizer before being sent to the remote control station. First, based on the Takagi-Sugeno (T-S) fuzzy theory, the nonlinear UMV system is molded as a T-S fuzzy model. Then a hybrid switched fuzzy system is established by taking the DoS attack and quantization effect into account. An observer-based sliding mode control (SMC) scheme is proposed to stabilize the system under DoS attack, and the observer gains and controller gains can be obtained by solving a set of matrix inequalities. Finally, a benchmark UMV system is used to show the effectiveness of control scheme.
In this article, the sliding mode control issue is investigated for a class of discrete-time Takagi-Sugeno fuzzy networked singularly perturbed systems via an observer-based technique. Moreover, to ...process the measurement output and schedule the transmission sequence for relieving the communication burden, a logarithmic quantizer and a weighted try-once-discard protocol are synthesized, which can further improve the network bandwidth utilization in networked control systems. Based on the fuzzy observer states, a novel fuzzy sliding surface is established by considering the singularly perturbed parameter properly, and we endeavor to synthesize a sliding mode control law such that the reachability of the prescribed sliding surface could be guaranteed. In addition, by virtue of the convex optimization theory and Lyapunov approach, sufficient conditions are developed to guarantee the asymptotic stability of the sliding mode dynamics as well as the error system with an expected <inline-formula><tex-math notation="LaTeX">H_{\infty }</tex-math></inline-formula> performance. Finally, a verification example is presented to illustrate the feasibility and effectivity of the proposed method.
The problem of asynchronous dissipative control is investigated for Takagi-Sugeno fuzzy systems with Markov jump in this paper. Hidden Markov model is introduced to represent the nonsynchronization ...between the designed controller and the original system. By the fuzzy-basis-dependent and mode-dependent Lyapunov function, a sufficient condition is achieved such that the resulting closed-loop system is stochastically stable with a strictly (<inline-formula> <tex-math notation="LaTeX"> {\mathcal {Q}} </tex-math></inline-formula>, <inline-formula> <tex-math notation="LaTeX"> {\mathcal {S}} </tex-math></inline-formula>, <inline-formula> <tex-math notation="LaTeX"> {\mathcal {R}} </tex-math></inline-formula>)-<inline-formula> <tex-math notation="LaTeX"> {\alpha } </tex-math></inline-formula>-dissipative performance. The controller parameter is derived by applying MATLAB to solve a set of linear matrix inequalities. Finally, we present two examples to confirm the validity and correctness of our developed approach.
The direct functionalization of allylic C−H bonds with nucleophiles minimizes pre‐functionalization and converts inexpensive, abundantly available materials to value‐added alkenyl‐substituted ...products but remains challenging. Here we report an electrocatalytic allylic C−H alkylation reaction with carbon nucleophiles employing an easily available cobalt–salen complex as the molecular catalyst. These C(sp3)−H/C(sp3)−H cross‐coupling reactions proceed through H2 evolution and require no external chemical oxidants. Importantly, the mild conditions and unique electrocatalytic radical process ensure excellent functional group tolerance and substrate compatibility with both linear and branched terminal alkenes. The synthetic utility of the electrochemical method is highlighted by its scalability (up to 200 mmol scale) under low loading of electrolyte (down to 0.05 equiv) and its successful application in the late‐stage functionalization of complex structures.
An electrocatalytic allylic C−H alkylation reaction with carbon nucleophiles is reported, which employs an easily available cobalt–salen complex as the molecular catalyst. The method is characterized by its excellent functional group tolerance, substrate compatibility with both linear and branched terminal alkenes, and scalability (up to 200 mmol scale) with a low loading of electrolyte (down to 0.05 equiv).
