An important factor for the high performance of lightharvesting devices is the presence of surface trappings. Therefore, understanding and controlling the carrier recombination of the organic−inorganic hybrid perovskite surface is critical for the device design and optimization. Here, we report the use of aluminum zinc oxide (AZO) as the anode to construct a p−n junction structure MAPbBr 3 nuclear radiation detector. The AZO/MAPbBr 3 /Au detector can tolerate an electrical field of 500 V•cm −1 and exhibit a very low leakage current of ∼9 nA, which is 1 order of magnitude lower than that of the standard ohmic contact device. The interface state density of AZO/MAPbBr 3 contact was reduced from 2.17 × 10 10 to 8.7 × 10 8 cm −2 by annealing at 100°C under an Ar atmosphere. Consequently, a photocurrent to dark current ratio of 190 was realized when exposed to a green light-emitting diode with a wavelength of 520 nm (∼200 mW•cm −2). Simultaneously, a high X-ray sensitivity of ∼529 μC•Gy air −1 cm −2 was achieved under 80 kVp X-ray at an electric field of 50 V•cm −1. These results demonstrate the use of surface engineering to further optimize the performance of MAPbBr 3 detectors, which have many potential applications in medical and security detection with low radiation dose brought to the human body.

This paper proposes an adaptive dynamic programming (ADP)-based decentralized event-triggered control strategy for large-scale nonlinear systems with event-triggered scheme to efficiently reduce communication cost and computational burden. Under the event-triggered mechanism, an local neural networks (NNs)-based observer is introduced to identify the mismatched interconnections and the estimation error is guaranteed to be uniformly ultimately bounded (UUB). Then, a decentralized triggering condition related to the approximation error of interconnections is designed to reduce the local controller updates with guaranteed overall stabilization of large-scale systems. By virtue of critic-only structure, the local optimal control policy can be approximated via aperiodic tuning rule using ADP. In addition, the closed-loop large-scale system ensures to be asymptotically stable with adaptive triggering threshold according to Lyapunov method. Finally, the simulation results justify the theoretical analysis and illustrate the effectiveness of the proposed event-triggered control (ETC) strategy. KEYWORDSadaptive dynamic programming, critic NNs, event-triggered, NN-based observer INTRODUCTIONNowadays, there are many interconnected large-scale systems existing in daily life, engineering area, and other practical applications, such as ecosystems, transportation system, communication systems, power systems, and so forth. Besides, with the growing demand of production quality and economic efficiency for these large-scale systems, investigating the optimal control for interconnected large-scale systems is a hot research topic. In general, interconnections coupled by subsystems pose big challenges to design the control approaches for large-scale systems because they often have negative effect on system performance and may even lead to system instability [1-3]. Therefore, more and more attention has been paid on how to design effectively optimal controllers to achieve good performance for interconnected large-scale systems [4,5].Different control strategies have been developed to address interconnected large-scale systems, which are broadly categorized into centralized control, distributed control and decentralized control. The classical centralized control requires information of all subsystems and control integrity is dominated by the centralized controller, so it is impractical for the lack of errors tolerance and growing dimension of large-scale systems [6]. The distributed control algorithm guarantee the overall

The energy resolution of a LaBr3(Ce) scintillation counter can reach 2.7% (662 keV) at room temperature. As a radiation measuring device, it has remarkably good characteristics. However, the LaBr3(Ce) crystal has its own intrinsic radioactivity background, which mainly comes from 138 La and from 227 Ac and its daughters. 138 La can emit β, γ and X-rays through β and γ decay; 227 Ac and its daughters can emit α, β and γ-rays through α, β and γ decay. α, γ and X-ray energy are characteristic while β-ray energy is continuous. The energy of α, β and X-rays is mainly deposited in the crystal unless the α, β and X-rays at the edge of the crystal can escape from the crystal. Therefore, the α, β, γ and X-rays generated by the intrinsic radioactivity of the crystal are superimposed on the instrument spectrum, which makes the instrument spectrum more complicated and produces the coincidence summing effects of γ + X, γ + β and γ + α. In this research, the GEANT4.9.5 software package was used to simulate the spectra of α, β, γ and X-rays. On the basis of a combination of fitting decomposition and reconstruction, the simulation spectrum of the LaBr3(Ce) self-radioactive background was obtained accurately and was verified by using physical experiments.

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