RESUMEN
The electrochemical CO2 reduction reaction (CO2RR) has become a promising technology to resolve globally accelerating CO2 emissions and produce chemical fuels. In this work, the electrocatalytic performance of transition metal (TM = Cu, Cr, Mn, Co, Ni, Mo, Pt, Rh, Ru and V) triatomic clusters embedded in a graphdiyne (GDY) monolayer (TM3@GDY) for CO2RR is investigated by density functional theory (DFT) calculations. The results indicate that Cr3@GDY possesses the best catalytic performance with a remarkably low rate-limiting step of 0.39 eV toward the CO2 product, and it can also effectively suppress the hydrogen evolution reaction (HER) during the entire CO2RR process. Studies on the rate-limiting steps (CHO* + H+ + e- â CHOH) of Crn@GDY (n = 1-4) structures demonstrate that the high catalytic performance is attributed to the strong synergistic reaction of three Cr atoms interacting with the C atom for the Cr3@GDY structure. The strong synergistic reaction gives rise to the weakest interaction between O-Cr atoms, which leads to the strongest interaction between O-H atoms and makes the hydrogenation process easier for the Cr3@GDY structure. Furthermore, ab initio molecular dynamics simulations (AIMD) at 500 K reveal the high thermodynamic stability of the Cr3@GDY structure. These studies may provide a new approach for designing highly efficient electrocatalysts for the CO2RR under ambient conditions.
RESUMEN
The imaging quality of infrared detection systems over time directly affects their ability to track targets accurately. In this study, a prediction scheme for the image quality of infrared detection system under hypersonic conditions based on time accuracy has been developed. Further, based on the time discretization, a calculation model has been established for the prediction scheme to perform numerical simulation. In particular, for verifying the reliability of this prediction method and the associated numerical calculation model, a comparison has been made between the numerical simulation results and the wind tunnel test results. The maximum error of the comparison result is less than 4.5%, and the reliability of the method proposed in this paper has been proved.
RESUMEN
In this paper, the von Karman surface is used in the configuration design of the infrared conformal dome to improve its aerodynamic performance. The principle of differential geometry is used to study the geometric characteristics of the von Karman dome. Additionally, by using ray tracing, the geometric aberrations and wave aberrations of the von Karman dome are analyzed. Further, considering the geometric characteristics and aberration characteristics, an optimization method for the configuration of the von Karman dome is proposed. To prove the effectiveness of the optimization method, the aberrations introduced by the conformal dome after the configuration optimization and the original von Karman dome are compared. The comparison showed that the geometric aberration of the optimized conformal dome is reduced by 43.68%. The optimization method can significantly correct the aberration introduced by the von Karman dome and improve the guidance capability of infrared detection technology.
