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The red-emitting perovskite material has received widespread attention as a long-wavelength optical gain media. But the easy phase change in the air limits its practical application. Herein, red CsPbBr x I3âˆ' x /SiO2 quantum dots (QDs) are prepared by a ligand-mediated hot injection method in which 3-aminopropyl-triethoxysilane (APTES) is used instead of the usual oleylamine (OAm) ligand. Through the hydrolysis of amino groups, a thin silicon layer is formed on the QD surface, improving the stability and without causing the aggregation of QDs. We find that the ratio of I/Br and the size of QDs can be tuned by adjusting the APTES amount. Moreover, this ligand-mediated synthesis effectively passivates the surface defects, so the photoluminescence quantum yield is remarkably improved, and the carrier lifetime is prolonged. The amplified spontaneous emission is achieved under 532 nm nanosecond laser excitation. Compared with the original CsPbBrI2-OAm QD films, the threshold of CsPbBr x I3âˆ' x /SiO2 QD films is reduced from 403.5 to 98.7 ÎĽ J cmâˆ'2, and the radiation stability is significantly enhanced. Therefore, this material shows great potential in the random laser field. [ABSTRACT FROM AUTHOR]

All inorganic cesium lead halide perovskite (CsPbX3; X = Cl, Br, or I) quantum dots (QDs) have received widespread attention as a class of favorable optical gain materials. The key issue of CsPbX3 perovskites is their instability under light or exposure to air. Notably, the inherent phase instability of CsPbI3 QDs severely restricts the development of red-light emission. Herein, we propose a simple method to post-process CsPbBr3 QDs with a ZnI2 solution. The prepared CsPbBryI3−y (named CPBI-z, where z corresponds to the photoluminescence peaks' position) QDs exhibit adjustable photoluminescence in the range of 550–640 nm. The photoluminescence quantum yield is increased from 73.3% to 97.2% as the surface defects of QDs are passivated by I− and Zn2+. Compared with the pristine CsPbBr3 QDs, the post-processed QDs are more stable under ultraviolet irradiation and in the air. Aside from that, under 532 nm nanosecond laser excitation, CPBI-z QD films exhibit excellent amplified spontaneous emission performance. The CPBI-640 QD film shows a low threshold, 102 μJ cm−2 for red stable amplified spontaneous emission. [ABSTRACT FROM AUTHOR]

Polarization characteristics of microarrays of silver nanowires embedded in an anodic alumina membrane are theoretically investigated. The microarrays mainly transmit the p-polarized wave, whereas they strongly attenuate the s-polarized wave in the near- and mid-infrared spectral range. We show that the sizes (e.g., diameter, spacing, and ratio of diameter to spacing) of the nanowires strongly affect the optical losses for the polarized waves. It is predicted that large extinction ratios and small insertion losses can be simultaneously achieved by an appropriate choice of the ratio and the diameter. An optimized design of a nanowire grid polarizer at near- and mid-infrared wavelengths is presented. OCIS codes: 160.4760, 230.5440, 260.5430.

A monetary endogenous growth model revealed the significant long-term effects of inflation on economic growth. The model showed that the welfare costs of moderate inflation are large, which ranges from one-half percent to five percent for a yearly 10% monetary growth. The importance of monetary policy on economic growth was also emphasized by the endogenous growth model.

The nuclear heating rate is a critical parameter for reactor core design and irradiation tests, it is typically determined via experimental measurements in a reactor experimental channel. In-pile calibration of calorimeter is an important method for measuring the nuclear heating rate in a fission reactor. This paper summarizes the working principle of the common in-pile calorimeter and reviews the current situation and research progress with regard to in-pile calorimetry employed worldwide. The structural design and performance characteristics of single-cell and multi-cell (differential) calorimeters are compared, and the design method of multimodal integrated measurement device, which represents one of development directions of calorimeters, is introduced. Moreover, the in- and out-pile calibration principles and application methods are described. The advantages and disadvantages of the calibration methods are analyzed, and the developing trend and direction for next-generation in-pile calorimeters are prospected.

A monetary endogenous growth model is developed to assess the impact of anticipated inflation on per capita real variables and economic welfare. The model considers endogenous labor-leisure trade-off, specifies the functional forms of leisure disutility and provides comparative static results of responses to anticipated inflation. It is shown that contrary to existing studies, increased welfare costs result from reduced output growth.

In waveguided nematic liquid crystal random lasers (NLCRLs), we realize polarized random laser (RL) emission and discover that the waveguide effect reduces the transmission loss of the RL whose polarization is parallel to the liquid crystal molecules (LCMs). Compared with the traditional liquid crystal random lasers, the waveguide NLCRLs can achieve the regulation of RLs strength, polarization, and wavelength in the same structure. The electric field can drive the rotation of LCMs to control the RL polarization and intensity. The drop of horizontal polarization laser and the increase of vertical polarization laser prove the role of the waveguide effect. In addition, the disorder of the waveguided NLCRLs is highly sensitive to temperature, which makes it easy to control the wavelength and intensity of the RL. As the temperature rises, the waveguide effect is weakened, resulting in a weakening of the restriction along liquid crystal (LC) cell normal direction. The reduced laser intensity verifies the role of the waveguide effect. [ABSTRACT FROM AUTHOR]

Made a pioneering attempt to use the lattice sandwich structure in prosthetic foot design and pioneered the study for the lay-up design of the prosthetic foot. An innovative carbon fiber bionic prosthetic foot was designed using a sandwich structure. The effect of cross-ply on the prosthetic foot’s energy storage properties and vibration characteristics was investigated using the lattice sandwich structure prosthetic foot. The bionic prosthetic foot’s finite element model was constructed under normal working conditions according to international standards. The results indicate that the storage of strain energy increases with an increase in cross-ply under heel-strict working conditions. Under the toe-off condition, the strain energy distribution increases with the increase in cross-ply. The cross-ply number influences the mode of displacement of the bionic foot. The natural frequencies of the bionic foot increase with the increase in the cross-ply.

With the increasing penetration of distributed power sources, the stochastic and fluctuating nature of distributed power sources poses a great challenge to the reactive power optimization of the distribution network system. In this study, a dynamic reactive power optimization model with two-stage robust optimization is established, proposing whether the energy storage is charged or discharged. The number of groups of group-switching capacitors is taken as the variables in the first stage. The power of the energy storage charging and discharging and the amount of static reactive power compensator compensation are placed in the second stage. The control strategy in the first stage ensures that the control strategy in the second stage can maintain the safe and stable operation of the distribution network under the worst scenarios. The grid-storage joint optimization technology based on distributed architecture establishes an optimization planning model for the distribution network energy storage system with the goal of optimal technical and economic performance of the transmission and distribution network and considering the constraints of safe and stable operation of the transmission and distribution network, respectively. The PG&E-69 node system arithmetic example is used to verify the effectiveness and feasibility of the proposed model and algorithm. The results of the arithmetic example show that the strategy obtained based on the robust optimization model can achieve voltage magnitude stability within the safety range of 1.0-1.05 p.u. in the simulation scenario that has the best economy. At the same time, the mismatches of each distribution system under cooperative planning are all 0, which indicates that the proposed optimization strategy can fully cooperate with the resources of transmission and distribution networks, promote the safe consumption of clean energy, effectively improve the economy of transmission and distribution networks, and achieve the goal of “mutual benefit and win-win”.

This paper explores the principle of deep reinforcement learning algorithm application and constructs the digital teaching model of Civics through the recurrent neural network, Markov decision process, Actor-Critic algorithm and collaborative filtering recommendation algorithm. On this basis, the state representation model and decision-making model are invoked to improve the diversity optimization recommendation of the deep reinforcement learning algorithm. Aiming at the problems existing in the practical application of the OBE concept, the model constructed in this paper is utilized to propose a multi-platform integration of the Civics digital learning model. The objective of empirical and simulation experiments is to confirm the model’s implementation and recommendation effects, respectively. In the validation of hyperparameter d and N values, the DQN model achieves the optimal recommendation effect when the d values are 65 and 63 on the HetRec and MovieTweetings datasets. During the implementation of the digital teaching evaluation of the course Civics, more than 60% of the students rated the teacher’s feedback session higher. Overall, the 6 dimensions were rated higher, and the number of students who chose to be fully compliant and conforming was more than 200.