Recently, artificial intelligence research has driven the development of stretchable and flexible electronic systems. Conductive hydrogels are a class of soft electronic materials that have emerging applications in wearable and implantable biomedical devices. However, current conductive hydrogels possess fundamental limitations in terms of their antibacterial performance and a mechanical mismatch with human tissues, which severely limits their applications in biological interfaces. Here, inspired by animal skin, a conductive hydrogel is fabricated from a supramolecular assembly of polydopamine decorated silver nanoparticles (PDA@Ag NPs), polyaniline, and polyvinyl alcohol, namely PDA@Ag NPs/CPHs. The resultant hydrogel has many desirable features, such as tunable mechanical and electrochemical properties, eye‐catching processability, good self‐healing ability as well as repeatable adhesiveness. Remarkably, PDA@Ag NPs/CPHs exhibit broad antibacterial activity against Gram‐negative and Gram‐positive bacteria. The potential application of this versatile hydrogel is demonstrated by monitoring large‐scale movements of the human body in real time. In addition, PDA@Ag NPs/CPHs have a significant therapeutic effect on diabetic foot wounds by promoting angiogenesis, accelerating collagen deposition, inhibiting bacterial growth, and controlling wound infection. To the best of the authors' knowledge, this is the first time that conductive hydrogels with antibacterial ability are developed for use as epidermal sensors and diabetic foot wound dressing.

A technique was developed to achieve enhanced Raman scattering of the silicon photon modes using closely packed micro-and submicron silica spherical particles. Investigation on the particle-size dependence of Raman enhancement revealed that the strongest enhancement occurs when the particle diameter is equal to the spot size of the incident laser beam. Calculations using the OPTIWAVE™ software based on the finite difference time domain algorithm under the perfectly matched layer boundary conditions were carried out. The results showed that photonic nanojets are formed in the vicinity outside the particles along the propagation direction of incident light. It was found that the nanojets are confined to a length of 100 nm with a waist of 120 nm. The presence of the strongly localized electromagnetic fields within the nanojets accounts for the enhanced Raman scattering. This technique has potential applications both in modern and traditional areas of surface science such as surface oxidation, adhesion, corrosion, and catalytic processes, and many other areas in biology, chemistry, materials science, and microelectronics.

We report here a facile approach for flexible integration of high efficiency surface enhanced Raman scattering (SERS) monitors in a continuous microfluidic channel. In our work, femtosecond laser direct writing was adopted for highly localizable and controllable fabrication of the SERS monitor through a multi-photon absorption (MPA) induced photoreduction of silver salt solution. The silver substrate could be shaped into designed patterns, and could be precisely located at the desired position of the microchannel bed, giving the feasibility for real-time detection during reactions. SEM and TEM images show that the silver substrates were composed of crystallized silver nanoplates with an average thickness of 50 nm. AFM results reveal that the substrates were about 600 nm in height and the surface was very rough. As representative tests for SERS detection, p-aminothiophenol (p-ATP) and flavin adenine dinucleotide (FAD) were chosen as probing molecules for microfluidic analysis at visible light (514.5 nm) excitation, exhibiting an enhancement factor of ~10(8). In addition, the combination of the SERS substrate with the microfluidic channel allows detection of inactive analytes through in situ microfluidic reactions.

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Renewable energy sources (RESs) are typically interfaced to the grid using power electronics which can cause their fault current characteristics to display significant low frequency harmonics and unbalanced sequence impedances. Such current characteristics can lead to the operation failure of fault component based directional relays. To demonstrate the influence of inverter-interfaced renewable energy generators (IIREGs) on directional relays in detail, analytical expressions for the IIREG equivalent positive-and negative-sequence superimposed impedances are derived in this paper. Considering various factors, the angular characteristics of the sequence superimposed impedances are investigated. Based on these attributes, it can be concluded that fault component based directional relays may be unable to operate in some circumstances. A novel high-frequency impedance-based protection scheme is proposed to manage the adaptability problem by determining the fault direction due to a stable impedance angle. The theoretical analysis and the proposed scheme are tested and verified through real time digital simulation (RTDS) simulation and field testing data.