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With the rapid advancement of electronic and information technologies, such as artificial intelligence, medical monitoring, virtual reality, and human–machine interaction, flexible wearable sensors have gained increasing importance for future smart life. Hydrogel materials have garnered widespread attention in the realm of wearable sensors due to their three-dimensional biomimetic structure, flexibility, biocompatibility, and other advantageous properties. However, current hydrogel sensors suffer from issues such as low conductivity, mechanical degradation, and water loss. By introducing two-dimensional transition metal carbides and nitrides, so-called MXenes, to hydrogels, the MXene hydrogels are expected to show high electrical conductivity and excellent mechanical strength. Here in this manuscript, the design principles of MXene hydrogels are discussed in detail, together with strategies for enhancing the hydrogels' electrical and mechanical properties toward next-generation wearable sensors. Challenges and potential applications, especially in strain sensors, pressure sensors, temperature sensors, biosensors, humidity sensors, etc., are provided. This work is expected to provide insightful instructions for designing advanced hydrogel sensors. [ABSTRACT FROM AUTHOR]

Scanning Electron Microscope (SEM) is a crucial tool for studying microstructures of ceramic materials. However, the current practice heavily relies on manual efforts to extract porosity from SEM images. To address this issue, we propose PSTNet (Pyramid Segmentation Transformer Net) for grain and pore segmentation in SEM images, which merges multi-scale feature maps through operations like recombination and upsampling to predict and generate segmentation maps. These maps are used to predict the corresponding porosity at ceramic grain boundaries. To increase segmentation accuracy and minimize loss, we employ several strategies. (1) We train the micro-pore detection and segmentation model using publicly available Al2O3 and custom Y2O3 ceramic SEM images. We calculate the pixel percentage of segmented pores in SEM images to determine the surface porosity at the corresponding locations. (2) Utilizing high-temperature hot pressing sintering, we prepared and captured scanning electron microscope images of Y2O3 ceramics, with which a Y2O3 ceramic dataset was constructed through preprocessing and annotation. (3) We employed segmentation penalty cross-entropy loss, smooth L1 loss, and structural similarity (SSIM) loss as the constituent terms of a joint loss function. The segmentation penalty cross-entropy loss helps suppress segmentation loss bias, smooth L1 loss is utilized to reduce noise in images, and incorporating structural similarity into the loss function computation guides the model to better learn structural features of images, significantly improving the accuracy and robustness of semantic segmentation. (4) In the decoder stage, we utilized an improved version of the multi-head attention mechanism (MHA) for feature fusion, leading to a significant enhancement in model performance. Our model training is based on publicly available laser-sintered Al2O3 ceramic datasets and self-made high-temperature hot-pressed sintered Y2O3 ceramic datasets, and validation has been completed. Our Pix Acc score improves over the baseline by 12.2%, 86.52 vs. 76.01, and the mIoU score improves from by 25.5%, 69.10 vs. 51.49. The average relative errors on datasets Y2O3 and Al2O3 were 6.9% and 6.36%, respectively. [ABSTRACT FROM AUTHOR]

Hydrogen has the characteristics of high combustion value, no pollution of combustion products, and high element content, which is considered to be the most advantageous green energy in the future. The mobile hydrogen source can achieve the preparation of hydrogen at any time, effectively avoiding the safety hazards of hydrogen in the storage and transportation process. Magnesium-based active materials, which can release hydrogen by hydrolysis at room temperature, can be ideal materials for mobile hydrogen sources. This article presents a comprehensive review of recent research progress on magnesium-based active materials, focusing on four aspects of magnesium hydrolysis reaction research: preparation methods of magnesium materials, addition of catalysts, reaction media, and applications of active magnesium-based materials. In addition, the promotion mechanism of magnesium hydrolysis reaction for different preparation methods, catalysts, and reaction media is also summarized in detail. Finally, the limitations of the current research on magnesium-based active materials are analyzed, and the future research and application aspects of this material are prospected. [ABSTRACT FROM AUTHOR]