Object Detection in Multispectral Remote Sensing Images Based on Cross-Modal Cross-Attention.

In complex environments a single visible image is not good enough to perceive the environment, this paper proposes a novel dual-stream real-time detector designed for target detection in extreme environments such as nighttime and fog, which is able to efficiently utilise both visible and infrared images to achieve Fast All-Weatherenvironment sensing (FAWDet). Firstly, in order to allow the network to process information from different modalities simultaneously, this paper expands the state-of-the-art end-to-end detector YOLOv8, the backbone is expanded in parallel as a dual stream. Then, for purpose of avoid information loss in the process of network deepening, a cross-modal feature enhancement module is designed in this study, which enhances each modal feature by cross-modal attention mechanisms, thus effectively avoiding information loss and improving the detection capability of small targets. In addition, for the significant differences between modal features, this paper proposes a three-stage fusion strategy to optimise the feature integration through the fusion of spatial, channel and overall dimensions. It is worth mentioning that the cross-modal feature fusion module adopts an end-to-end training approach. Extensive experiments on two datasets validate that the proposed method achieves state-of-the-art performance in detecting small targets. The cross-modal real-time detector in this study not only demonstrates excellent stability and robust detection performance, but also provides a new solution for target detection techniques in extreme environments.

A macroporous carbon nanoframe for hosting Mott-Schottky Fe-Co/Mo2C sites as an outstanding bi-functional oxygen electrocatalyst.

Simultaneously optimizing the d-band center of the catalyst and the mass/charge transport processes during the oxygen catalytic reaction is an essential but arduous task in the pursuit of creating effective and long-lasting bifunctional oxygen catalysts. In this study, a Fe-Co/Mo2C@N-doped carbon macroporous nanoframe was successfully synthesized via a facile "conformal coating and coordination capture" pyrolysis strategy. As expected, the resulting heterogeneous electrocatalyst exhibited excellent reversible oxygen electrocatalytic performance in an alkaline medium, as demonstrated by the small potential gap of 0.635 V between the operating potential of 1.507 V at 10 mA cm-2 for the oxygen evolution reaction and the half-wave potential of 0.872 V towards the oxygen reduction reaction. Additionally, the developed Zn-air battery employing the macroporous nanoframe heterostructure displayed an impressive peak power density of 218 mW cm-2, a noteworthy specific capacity of 694 mA h gZn-1, and remarkable charging/discharging cycle durability. Theoretical calculations confirmed that the built-in electric field between the Fe-Co alloy and Mo2C semiconductor could induce advantageous charge transport and redistribution at the heterointerface, contributing to the optimization of the d-band center of the nanohybrid and ultimately leading to a reduction in the reaction energy barrier during catalytic processes. The exquisite macroporous nanoframe facilitated the rapid transport of ions and charges, as well as the smooth access of oxygen to the internal active site. Thus, the presented unique electronic structure regulation and macroporous structure design show promising potential for the development of robust bifunctional oxygen electrodes.

Interface engineering induced charge rearrangement boosting reversible oxygen electrocatalysis activity of heterogeneous FeCo-MnO@N-doped carbon nanobox.

The advancement of bifunctional oxygen catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is imperative yet challenging for the optimization of Zn-air batteries. In this study, we reported the successful incorporation of a novel Mott-Schottky catalytic site within a MnO-FeCo heterojunction into an N-doping carbon nanobox, taking into consideration the effects of the intrinsic electric field and hollow/porous support carriers for electrocatalyst design. As expected, the resulting heterogeneous catalyst exhibited an encouraging half-wave potential of 0.88 V and an impressive limiting-current density of 5.62 mA/cm2 for the ORR, as well as a minimal overpotential of 271 mV at 10 mA/cm2 for the OER, both in alkaline conditions. Furthermore, the Zn-air battery constructed with the heterojunction nanobox product displayed a decent potential gap of 0.621 V, an outstanding power density of 253 mW/cm2, a considerable specific capacity of 761 mAh/gZn, and exceptional stability, with up to 336 h of cycling charging and discharging operation. Consequently, this method of modulating the catalyst's surface charge distribution through an internal electric field at the interface and facilitating mass transport offers a novel avenue for the development of robust bifunctional oxygen catalysts.

Vacancy and doping engineering of Ni-based charge-buffer electrode for highly-efficient membrane-free and decoupled hydrogen/oxygen evolution.

The realization of the membrane-free two-step water electrolysis is particularly important yet challenging for the low-cost and large-scale supply of hydrogen energy. In this effort, Co-doped Ni(OH)2 nanosheets were successfully anchored onto the nickel foam (NF) substrate through the in-situ growth of metal-organic frame material and the subsequent alkali-etching technique. Using the well-regulated Co-doping Ni(OH)2@NF electrodes as a charge mediator, electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were decoupled on time scales, thus affording a membrane-free two-step route for H2 and O2 productions. In this architecture, the first HER process on the cathode could be maintained for 1300 s at a current of 100 mA, while the corresponding Ni(OH)2 charge mediator was simultaneously oxidized to NiOOH, with a decent cell voltage of 1.542 V. The subsequent OER process involved a reduction/regeneration of Ni(OH)2 (from NiOOH to Ni(OH)2) and an anodic O2-production, with an operating voltage of 0.291 V. Moreover, the Ni-Zn battery assembled through the combination of NiOOH and Zn sheet could replace the second step of OER to achieve the coupling of continuous H2-production and battery discharge, thus also providing a new way for hydrogen production without an external power supply. Experiment and theoretical calculations have shown that the cobalt-doping not only improved the conductivity of the charge-buffer electrode, but also shifted its redox potential cathodically and boosted the adsorption affinity of the buffer medium to OH- ions, both contributing to promoted HER and OER activity. Therefore, this decoupled water electrolysis device affords a promising pathway to support the efficient conversion of renewables to hydrogen.