Monitoring biophysical signals such as body or organ movements and other physical phenomena is necessary for patient rehabilitation. However, stretchable flexible pressure sensors with high sensitivity and a broad range that can meet these requirements are still lacking. Herein, we successfully monitored various vital biophysical features and implemented in-sensor dynamic deep learning for knee rehabilitation using an ultrabroad linear range and high-sensitivity stretchable iontronic pressure sensor (SIPS). We optimized the topological structure and material composition of the electrode to build a fully stretching on-skin sensor. The high sensitivity (12.43 kPa−1), ultrabroad linear sensing range (1 MPa), high pressure resolution (6.4 Pa), long-term durability (no decay after 12000 cycles), and excellent stretchability (up to 20%) allow the sensor to maintain operating stability, even in emergency cases with a high sudden impact force (near 1 MPa) applied to the sensor. As a practical demonstration, the SIPS can positively track biophysical signals such as pulse waves, muscle movements, and plantar pressure. Importantly, with the help of a neuro-inspired fully convolutional network algorithm, the SIPS can accurately predict knee joint postures for better rehabilitation after orthopedic surgery. Our SIPS has potential as a promising candidate for wearable electronics and artificial intelligent medical engineering owing to its unique high signal-to-noise ratio and ultrabroad linear range.

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Although wearable antennas have made great progress in recent years, how to design high-performance antennas suitable for most wireless communication systems has always been the direction of RF workers. In this paper, a new approach for the design and manufacture of a compact, low-profile, broadband, omni-directional and conformal antenna is presented, including the use of a customized flexible dielectric substrate with high permittivity and low loss tangent to realize the compact sensing antenna. Poly-di-methyl-siloxane (PDMS) is doped a certain proportion of aluminum trioxide (Al2O3) and Poly-tetra-fluoro-ethylene (PTFE) to investigate the effect of dielectric constant and loss tangent. Through a large number of comparative experiments, data on different doping ratios show that the new doped materials are flexible enough to increase dielectric constant, reduce loss tangent and significantly improve the load resistance capacity. The antenna is configured with a multisection microstrip stepped impedance resonator structure (SIR) to expand the bandwidth. The measured reflection return loss (S11) showed an operating frequency band from 0.99 to 9.41 GHz, with a band ratio of 146%. The antenna covers two important frequency bands, 1.71–2.484 GHz (personal communication system and wireless body area network (WBAN) systems) and 5.15–5.825 GHz (wireless local area network-WLAN)]. It also passed the SAR test for human safety. Therefore, the proposed antenna offers a good chance for full coverage of WLAN and large-scale development of wearable products. It also has potential applications in communication systems, wireless energy acquisition systems and other wireless systems.

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Phosphor-converted white light-emitting diodes (PC-WLEDs) are an energy-saving alternative to traditional light sources, for which efficient and thermal stable phosphors are in h i g h d e m a n d . H e r e , t h e N A S I C O N -t y p e Na 3+x □ 1−x Sc 2−x Mg x (PO 4 ) 3 :Eu 2+ (N□SM x PO:Eu 2+ ) phosphor is synthesized for Na vacancies repair. The photoluminescence quantum yield (PLQY) and the emission morphology of solid solution are dramatically affected by the composition, with the PLQY improving by 27% and the emission spectra red-shifting by 11 nm going from x = 0.0 to x = 0.3. These highlights likely stem from the enhanced structural rigidity and the distortion of NaO 6(8) polyhedra, respectively. Temperature-dependent emission spectra reveal the thermal stable luminescence of the series. A luminescence intensity of ≥90% relative to the room-temperature value is observed at 425 K. The LED device with the blending of N□SM 0.3 PO:Eu 2+ and commercial components generates CRI (colorrending indices) = 88 and CCT (correlated color temperatures) = 5209 K, characteristic of high-quality white light. More interestingly, the distortion of crystal lattice could switch to the migration of Eu ion to (Sc/Mg) site at x = 0.4. The phenomenon leads to the oxidation of Eu 2+ , optically rapidly weakening the photoluminescence. Modifying the lattice distortion in some type phosphors may be a very useful approach to improve the efficiency of luminescence materials.