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Abstract This study explores a novel multi-material 3D printing technique for fabricating bioinspired hydrogel-Rochelle salt composites, focusing on optimizing concentration, cooling, and coating parameters to enhance material performance. The hydrogel-Rochelle salt composite is a promising material due to its lightweight, mechanical robustness, and piezoelectric properties, making it suitable for applications in sensors, medical devices, and structural materials. A series of concentration tests was conducted to determine the optimal Rochelle salt concentration for achieving efficient curing depth and exposure time. The results identified 50wt% hydrogel/50wt% Rochelle salt as the optimal concentration, providing a balanced curing profile essential for ensuring reliable layer adhesion and structural consistency. To enable controlled crystallization, a cooling process was introduced, with a cooling time of 15 minutes found to be sufficient for complete crystallization to a depth of 500 microns. Thermal imaging and microscopy confirmed the stability of the crystalline structure within the hydrogel matrix, ensuring the material’s functional integrity. Additionally, applying a coating to the printed structure significantly improved surface uniformity and durability, embedding the crystalline elements more effectively within the hydrogel matrix and enhancing the composite’s overall structural integrity. This coating process allowed the composite to withstand repeated printing cycles, facilitating the construction of layered, multi-material structures with improved mechanical and functional properties. The results highlight the importance of fine-tuning concentration, cooling time, and coating techniques to achieve optimal performance in multi-material 3D printing. By addressing these factors, the study demonstrates a reliable approach to producing hydrogel-Rochelle salt composites with high structural quality and piezoelectric functionality. This method not only enhances the material’s durability and adhesion between layers but also opens new possibilities for creating customized, multifunctional materials. The developed process holds significant promise for applications that require precise control over material properties, such as wearable electronics, medical implants, and lightweight structural components. In conclusion, this research provides valuable insights into the fabrication of hydrogel-Rochelle salt composites through advanced 3D printing techniques. The findings offer a foundation for future exploration in multi-material printing and composite fabrication, paving the way for the development of versatile materials with tailored properties for diverse applications. 

Abstract Traditional piezoelectric materials, such as lead zirconate titanate (PZT), are widely used due to their superior ability to convert mechanical energy into electrical energy. However, these lead-based ceramics are highly toxic and environmentally hazardous. This report explores Rochelle salt as an eco-friendly alternative, despite its brittleness and lower piezoelectric properties compared to PZT. The study investigates methods to enhance the energy capture of Rochelle salt crystals(RS) by varying crystal volume, impact frequency, and force, as well as by incorporating the 3D-printed biomimetic structure inspired by the pomelo fruit peel, which is naturally optimized for absorbing out-of-plane crushing forces. Experimental crystals grown within this structure were compared with those grown without it, focusing on energy capture and durability. Additionally, units with a 64:36 crystal-to-resin ratio were designed to assess the impact of crystal volume on voltage output. The experiments involved varying impact frequencies (120 rpm and 250 rpm) and compression distances (0.034 and 0.068 inches) using a digital oscilloscope and a custom crank slider mechanism. The results indicate that reducing crystal thickness and increasing rpms enhance voltage capture, suggesting that biomimetic structures can significantly improve the mechanical and electrical performance of piezoelectric materials. 

The design and fabrication of 3D printed ATESs within vivoadhesion and application potential, shape design capability, as well as accessible and convenient fabrication and application process. 

As the crisis of confidence and trust in overseas foundries arises, the industry and academic community are paying increasing attention to Printed Circuit Board (PCB) security. PCB, the backbone of any electronic system hardware, always draws attackers’ attention as it carries system and design information. Numerous ways of PCB tampering (e.g., adding/replacing a component, eavesdropping on a trace and bypassing a connection) can lead to more severe problems, such as Intellectual Property (IP) violation, password leaking, the Internet of Things (IoT) attacks or even more. This paper proposes a technique of active self-defense PCB modules with zero performance overhead. Those protection modules will only be activated when the boards are exposed to the attacks. A set of PCBs with proposed protection modules is fabricated and tested to prove the effectiveness and efficiency of the techniques. 

The abrupt weakening of the East Asian summer monsoon (EASM) during Younger Dryas (YD) has been attributed to freshwater discharge into the North Atlantic ocean and resultant Northern Hemisphere cooling. Recent studies have found that sea ice variability in the Nordic Sea during the YD exerted a great influence upon the northern high-latitude climate. However, the influence of sea ice upon EASM evolution during YD event remains unclear. In this paper, we report two precisely-dated speleothem oxygen isotope records from the EASM-dominated region of central China. Our records archive abrupt changes in EASM variability during the YD event. Initially, there was a significant strengthening of the EASM during the mid-YD following the gradually increased Atlantic meridional overturning circulation (AMOC). Later this trend reversed at ∼12.15 ka due to northern high-latitude sea ice fluctuations and a consequent reduction of AMOC. At the YD termination, abrupt intensification of the EASM was synchronous with the rapid decline of sea-ice and recovery of the AMOC indicating that sea ice variability was a significant influence on high latitude climate and EASM variation during the YD. 

Abstract Adhesive tissue engineering scaffolds (ATESs) have emerged as an innovative alternative means, replacing sutures and bioglues, to secure the implants onto target tissues. Relying on their intrinsic tissue adhesion characteristics, ATES systems enable minimally invasive delivery of various scaffolds. This study investigates development of the first class of 3D bioprinted ATES constructs using functionalized hydrogel bioinks. Two ATES delivery strategies, in situ printing onto the adherend versus printing and then transferring to the target surface, are tested using two bioprinting methods, embedded versus air printing. Dopamine‐modified methacrylated hyaluronic acid (HAMA‐Dopa) and gelatin methacrylate (GelMA) are used as the main bioink components, enabling fabrication of scaffolds with enhanced adhesion and crosslinking properties. Results demonstrate that dopamine modification improved adhesive properties of the HAMA‐Dopa/GelMA constructs under various loading conditions, while maintaining their structural fidelity, stability, mechanical properties, and biocompatibility. While directly printing onto the adherend yields superior adhesive strength, embedded printing followed by transfer to the target tissue demonstrates greater potential for translational applications. Together, these results demonstrate the potential of bioprinted ATESs as off‐the‐shelf medical devices for diverse biomedical applications. 

Understanding the relationship among elemental compositions, nanolamellar microstructures, and mechanical properties enables the rational design of high-entropy alloys (HEAs). Here, we construct nanolamellar Al_xCoCuFeNi HEAs with alternating high– and low–Al concentration layers and explore their mechanical properties using a combination of molecular dynamic simulation and density functional theory calculation. Our results show that the HEAs with nanolamellar structures exhibit ideal plastic behavior during uniaxial tensile loading, a feature not observed in homogeneous HEAs. This remarkable ideal plasticity is attributed to the unique deformation mechanisms of phase transformation coupled with dislocation nucleation and propagation in the high–Al concentration layers and the confinement and slip-blocking effect of the low–Al concentration layers. Unexpectedly, this ideal plasticity is fully reversible upon unloading, leading to a remarkable shape memory effect. Our work highlights the importance of nanolamellar structures in controlling the mechanical and functional properties of HEAs and presents a fascinating route for the design of HEAs for both functional and structural applications.