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Metal halide perovskites have shown unique advantages compared with traditional optoelectronic materials. Currently, perovskite films are commonly produced by either multi-step spin coating or vapor deposition techniques. However, both methods face challenges regarding large-scale production. Herein, we propose a straightforward in situ growth method for the fabrication of CsPbBr3 nanocrystal films. The films cover an area over 5.5 cm × 5.5 cm, with precise thickness control of a few microns and decent uniformity. Moreover, we demonstrate that the incorporation of magnesium ions into the perovskite enhances crystallization and effectively passivates surface defects, thereby further enhancing luminous efficiency. By integrating this approach with a silicon photodiode detector, we observe an increase in responsivity from 1.68 × 10−2 A/W to 3.72 × 10−2 A/W at a 365 nm ultraviolet wavelength. [ABSTRACT FROM AUTHOR]

Deep sea mineral analysis with X-rays requires ultra water-stable and large-scale X-ray sensitive materials. Perovskite nanocrystals are promising for X-ray detection. However, their surface defects usually affect luminescence properties and long-time stability. Herein, a strategy combining polymer encapsulation and vitamin doping is proposed in this work. The perovskite nanocrystals are in situ grown in the polymer matrix, which can maintain over 96% of the initial luminous intensity in water and ambient conditions for 480 and 2880 hours, respectively. Moreover, the perovskite film exhibits excellent stability in high pressure/salted/sulfur-rich environments. In addition, vitamins are introduced into the perovskite precursor, which promote the crystallization of the perovskite film, reducing the grain boundaries and adequately passivating the surface defects. The photoluminescence and radioluminescence intensity of the perovskite film are improved nearly 2-fold. By the in situ spraying growth method, the perovskite film is obtained over 100 cm2 with high uniformity (root-mean-square roughness of 1.06 nm). The perovskite scintillator film exhibits a light yield of 9001 photons per MeV and high spatial resolution of 9.0 lp mm−1. This work is expected to promote deep-sea mineral detection by X-rays. [ABSTRACT FROM AUTHOR]

In order to achieve visual measurement error compensation for the surface of thin-walled components with chatter, a new real-time adaptive correction method for chatter motion error is proposed in this paper. Firstly, according to the mechanism of the chatter effect, an error analysis model of the dynamic structured light phase principal value is derived. Then, a real-time optimization method for the motion phase error in the frame of structured light projection is proposed. Meanwhile, a compensation method based on an adaptive grating projection period is proposed to eliminate the cumulative error of inter-frame chatter motion. Finally, a structured light visual inspection system and an experimental platform for chattering thin-walled parts are established for experimental verification. The experimental results under slight and severe chatter conditions indicate that the proposed method can optimize the phase errors within the projected frame in real time under any scenario, compensate for the cumulative errors between projected frames, and improve the point cloud accuracy of real-time 3D reconstruction. [ABSTRACT FROM AUTHOR]

The control of the evaporation rate is essential to the long-distance transportation of liquid hydrogen (LH 2). This paper conducts a numerical investigation of the thermodynamic characteristics in tanks with baffles under LH 2 sloshing conditions by establishing a computational fluid dynamics (CFD) model. The pressurization rate and vapor-liquid interface sloshing behavior predicted by the numerical model is validated against experimental data. The effects of baffles, amplitude, frequency, and storage pressure on thermodynamic characteristics such as temperature, pressurization rate, and evaporation rate of the LH 2 tank under sinusoidal sloshing are analyzed in detail. The simulation results suggest that adding baffles can effectively suppress the pressure fluctuation of LH 2 under sloshing conditions, but baffles as a "thermal bridge" accelerate the pressurization rate in the tank. Adding baffles during smooth transportation accelerates the pressurization rate. The baffles gradually demonstrate the effect of suppressing the pressurization rate as the acceleration amplitude increases. Assuming that the LH 2 evaporation rate is stable for a certain value, the daily evaporation rates in the LH 2 tank account for 2.59 % and 5.13 % when the maximum acceleration is 5.92 m/s2 and 9.87 m/s2, respectively, which contradicts the long-term storage goal of LH 2. The slower the sloshing frequency, the higher the maximum liquid phase level in the tank, and the faster the evaporation rate. The sloshing frequency has little effect on the LH 2 pressurization and evaporation rates compared to the amplitude. The growth of pressure decreases from 139.9 Pa to 85.62 Pa for a period of 15 s when the storage pressure in the tank increases from 0.1 MPa to 0.6 MPa. This study provides guidlines for the in-depth investigation of the thermodynamic behavior in LH 2 tanks during transportation. [Display omitted] • Thermodynamic analysis of liquid hydrogen tanks during sinusoidal sloshing. • LH 2 evaporation correlates positively with amplitude and negatively with frequency. • Increasing the storage pressure slows down the evaporation rate. • Baffles help reduce pressure fluctuation magnitude but increase evaporation. • Effects of Baffles on evaporation rate become insignificant for severe sloshing. [ABSTRACT FROM AUTHOR]

Reducing the heat leakage during liquid hydrogen storage (LH 2) has been a critical issue for the long-distance transportation and large-scale application of hydrogen. A composite thermal insulation structure for LH 2 tanks, which integrated the variable density composite multilayer insulation (FVD-MLI) and vapor-cooled shield (VCS) with para-to-ortho hydrogen conversion (P–O) catalysts, is used. Based on the "Layer by Layer" models, para-hydrogen equilibrium fractions with different VCS temperatures and P–O efficiency with different flow rates are combined. The thermal effects of P–O in VCS are considered. Experimental results prove the insulation performance calculation model's accuracy. The heat leakage and temperature profile after filling the P–O catalysts in single VCS and double VCSs are obtained. The optimal insulation positions of single VCS and double VCSs are determined, and the consequence of the vacuum level on the insulation performance is discussed in detail. Increasing the VCS number from single to double and adding P–O catalysts can effectively improve the LH 2 tank's insulation performance. Compared with the single VCS, the heat flux through LH 2 tanks with double VCSs is reduced by 25.6%. The heat leakages to the tanks can be further reduced by 5.08% and 7.45%, respectively, after adding P–O catalysts in single VCS and double VCSs. Moreover, the cooling effects of P–O shift the optimal position of VCS towards the cold boundary. The single VCS optimal position is moved from 58% of the insulation structure thickness to 50.6%. The optimal positions of double VCSs are moved from 38.9% to 75%–31.1% and 71.7%, respectively. It is found that adding P–O catalysts and increasing the VCS numbers can effectively increase the insulation effect regardless of the vacuum degree between the thermal insulation structure. However, considering the P–O efficiency, the insulation improvement effects after adding P–O catalysts decrease with interlayer vacuum deterioration. • Adding VCS with para-to-ortho hydrogen conversion in insulation structure. • P–H 2 equilibrium fractions and P–O efficiency are combined. • Heat fluxes can be decreased by 5.08% and 7.45% by adding P–O catalysts. [ABSTRACT FROM AUTHOR]

With high quantum efficiency, unique bandgap, and narrow emission band, all-inorganic CsPbI3 halide perovskite nanocrystals have been widely acknowledged as competitive candidates for pure red light-emitting diodes (LEDs). However, the large-scale manufacturing and stability of CsPbI3 perovskites are the main obstacles for practical LEDs. In this work, by Mg2+/Yb3+ codoping, we successfully improve the luminous intensity (192%) in an ambient environment. What is more, these ionic doped CsPbI3 perovskite nanocrystals are thermally stable at 120 °C. Based on these perovskite nanocrystals, we also fabricate large-scale patterned LEDs (25.4 × 25.4 mm). At a bias voltage of 6 V, the fabricated LEDs exhibit a luminance of 749 cd m–2. At a current density of 6.4 mA cm–2, the fabricated LEDs achieved an external quantum efficiency of 10.9%. This result is expected to fuel the rapid growth of large-area pure red LEDs. [ABSTRACT FROM AUTHOR]

Heritage crimes can result in the significant loss of cultural relics and predicting them is crucial. To address the issues of inconsistent textual information format and the challenge of preventing and combating heritage crimes, this paper develops a system that extracts crime elements and predict heritage crime occurrences. The system comprises two deep-learning models. The first model, Bi-LSTM + CRF, is constructed to automatically extract crime elements and perform spatio-temporal analysis of crimes based on them. By integrating routine activity theory, social disorder theory, and practical field experience, the research reveals that holidays and other special days (SD) perform a critical role as influential factors in heritage crimes. Building upon these findings, the second model, LSTM + SD, is constructed to predict excavation-type heritage crimes. The results demonstrate that the model with the introduction of the holiday factor improves the RMSE and MAE by 6.4% and 47.8%, respectively, when compared to the original LSTM model. This paper presents research aimed at extracting crime elements and predicting excavation-type heritage crimes. With the ongoing expansion of data volume, the practical significance of the proposed system is poised to escalate. The results of this study are expected to provide decision-making support for heritage protection departments and public security authorities in preventing and combating crimes. [ABSTRACT FROM AUTHOR]