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Hydrogel sensors are widely utilized in soft robotics and tissue engineering due to their excellent mechanical properties and biocompatibility. However, in high‐water environments, traditional hydrogels can experience significant swelling, leading to decreased mechanical and electrical performance, potentially losing shape, and sensing capabilities. This study addresses these challenges by leveraging the Hofmeister effect, coupled with directional freezing and salting‐out techniques, to develop a layered, high‐strength, tough, and antiswelling PVA/MXene hydrogel. In particular, the salting‐out process enhances the self‐entanglement of PVA, resulting in an S‐PM hydrogel with a tensile strength of up to 2.87 MPa. Furthermore, the S‐PM hydrogel retains its structure and strength after 7 d of swelling, with only a 6% change in resistance. Importantly, its sensing performance is improved postswelling, a capability rarely achievable in traditional hydrogels. Moreover, the S‐PM hydrogel demonstrates faster response times and more stable resistance change rates in underwater tests, making it crucial for long‐term continuous monitoring in challenging aquatic environments, ensuring sustained operation and monitoring. [ABSTRACT FROM AUTHOR]

To improve the expandability, seeding accuracy, and operating speed range of the electric drive system (EDS) of precision seeders, this study constructed an EDS based on a controller area network (CAN) bus and designed a motor controller based on a field-orientated control (FOC) algorithm. Full-factorial bench and field tests based on seed spacing (0.1, 0.2, and 0.3 m) and operating speed (3, 6, 9, 12, and 15 km/h) were carried out to evaluate the performance of the EDS. The results of bench tests showed that seeding quality varied inversely with operating speed and positively with seed spacing. The average quality of feed index (QFI) at 0.1, 0.2, and 0.3 m seed spacing in bench tests was 88.38%, 96.67%, and 97.36%, with the average coefficient of variation (CV) being 20.13%, 16.27%, and 13.20%. Analysis of variance confirmed that both operating speed and seed spacing had a significant effect on QFI and CV (p < 0.001). The analysis of motor rotational speed accuracy showed that the relative error of motor rotational speed above 410 rpm did not exceed 2.24%, and the relative error had less influence on the seeding quality. The average QFI was 85.93%, 95.91%, and 96.24%, with the average CV being 21.12%, 15.50%, and 16.49% at 0.1, 0.2, and 0.3 m seed spacing in field tests. The methods and results of this study can provide a reference for the design and optimization of the EDS in a maize precision seeder and provide an effective solution for the improvement of maize yields. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) had room temperature response, large surface area, and excellent mechanical properties, making them favorable for the design of flexible, wearable, and portable gas sensors. However, CNTs were lacking in response and selective response to different gases, such as H 2 S. Here, we demonstrated a flexible H 2 S ppb-level gas sensor based on a carbon nanotube/amorphous Fe 2 O 3 (CNT/Fe 2 O 3 ) film at room temperature, which was fabricated via a simple one-step solvent-thermal method. The CNT/Fe 2 O 3 film gas sensor exhibited a high selective response to H 2 S (with a response of 55.1% to 100 ppb H 2 S), rapid reversible response at room temperature (with a response time of ∼127 s to 100 ppb H 2 S), and low limit of detection to about 2 ppb. Additionally, the CNT/Fe 2 O 3 film maintained good sensing performance under various bending conditions and could be further fabricated into the fiber gas sensor device via wet stretching, retaining response at the ppb level (with a response of 18.6% to 100 ppb H 2 S). This research on a flexible gas sensor device based on the CNT film/fiber opened up new possibilities for wearable portable electronic device applications.