At present, flexible pressure-sensitive materials generally have problems with weak adhesion and poor wear resistance, which easily result in friction failure when used for plantar pressure detection. In this study, a flexible pressure sensor with the advantages of a wide detection range, fast recovery, and good abrasive resistance was designed and prepared based on the screen printing process. The pressure-sensitive unit with a structural size of 5 mm× 8 mm was a functional material system due to the use of graphene and epoxy resin. The influence of the different mass ratios of the graphene and epoxy resin on the sensing properties was also studied. The test results showed that when the mass ratio of graphene to epoxy resin was 1:4, the response time and recovery time of the sensing unit were 40.8 ms and 3.7 ms, respectively, and the pressure detection range was 2.5–500 kPa. The sensor can detect dynamic pressure at 0.5 Hz, 1 Hz, 2 Hz, 10 Hz, and 20 Hz and can withstand 11,000 cycles of bending. In addition, adhesion tests showed that the high viscosity of the epoxy helped to improve the interlayer bond between the pressure-sensitive materials and the flexible substrate, which makes it more suitable for plantar pressure detection environments, where friction is common.

Although arrayed waveguide gratings (AWGs) are widely used in fiber Bragg grating (FBG) demodulation systems, their applications in real environments have been limited due to their narrow dynamic range and inability to continuously demodulate FBGs because of the finite bandwidth of AWG channels. Here, we developed a wide-dynamic-range, high-accuracy, continuous-demodulation FBG interrogator utilizing a dual-input channel on-chip silicon AWG. The introduction of two input channels in the AWG allowed two spectral peaks in each channel; therefore, staggered spectral peaks were realized. A joint-peak demodulation algorithm based on this spectrum is proposed to improve the dynamic range and demodulation accuracy. With the proposed structure and algorithm, we achieved continuous interrogation with a demodulation accuracy of 25.58 pm and a dynamic range of 24.5 nm in the 1537.5-1565.3 nm wavelength region. The relative demodulation accuracy within the full range reaches 0.1%. The dynamic range of adjacent channels is 5.4 nm, which is approximately 4 times greater than the dynamic range of an FBG conventional demodulation system using an AWG, and the relative demodulation accuracy is 0.47%. This developed interrogator, with a core size of 420 μm × 300 μm, theoretically explained and experimentally verified the possibility of the accurate measurement of an arbitrary FBG wavelength with high demodulation accuracy in the measurement range. This work achieved continuous monitoring of external temperature by FBGs and demonstrated their significant potential in expanding the application field of FBGs.

Giant magnetoresistance (GMR) sensors have been widely used in current detection, compass, automobile, and Internet of Things. The linearity of GMR sensors relies on a magnetic annealing process above the blocking temperature of the antiferromagnetic layer, which causes the same magnetization directions in the free and pinned ferromagnetic layers. Here we construct an orthogonal magnetic anisotropic structure by using a relatively low annealing temperature of 145 °C, where the magnetization direction of the free layer is perpendicular to that of the pinned layer so that a linear output can be realized. Quantitative magneto-optical kerr microscope (MOKE) is used to investigate the vector distribution of the magnetic domains, showing that an orthogonal anisotropy is established by the low temperature annealing process. GMR magnetic field sensor with a sensitivity of 0.78 mV/V/Oe and a measurement range of −20 to 20 Oe is demonstrated, which provides an effective method to enhance the linearity of the magnetic sensors with spin valve structures.

The voltage modulation in spin dynamics via the spin-lattice coupling (SLC) effect has been investigated in epitaxial La_0.5Sr_0.5MnO₃/PMN-PT multiferroic heterostructures. The critical angle for the disappearance of the first exchange (FEX) spin wave has been observed around 67° experimentally and been shifted about 4° by applying an electric field (E-field). In particular, at the critical angle, the FEX spin wave can be switched “on” and “off” by voltages, showing great potential in realizing magnonic devices. Moreover, the FEX spin wave resonance shift of 187 Oe at 173 K has been realized by the voltage driven SLC effect, which is a little larger than piezostrain-induced ferromagnetic resonance shift of 169 Oe. The experimental results can be well-explained by the modified Puszkarski spin wave theory.

Considering the magnetic shielding requirements of both geomagnetic field and 50 Hz power-line frequency in the complex working conditions of the power grid, an electromagnetic shielding system combining active and passive modes is proposed in this article. A three-dimensional Helmholtz coil with a magnetic shielding barrel nested inside is established by the COMSOL simulation tool, and the magnetic shielding efficiency of the system is analyzed. Comparing different materials, the simulation results indicate that permalloy alloy exhibits better shielding performance than pure iron and nickel materials. Additionally, the overall shielding efficiency of the shielding barrel increases linearly with the number of multiple layers. Under the combined active and passive electromagnetic shielding conditions, the system achieves a shielding efficiency of S_E = 113.98 dB, demonstrating excellent performance in shielding both AC and DC interference magnetic fields. This study provides theoretical guidance for the construction of magnetic shielding systems in electromagnetic interference environment.

Here, we present a high-precision demodulation method that supports the arrayed waveguide grating (AWG) system, which includes a 1 × 8 AWG as the primary filter with a 0.5 nm channel spacing and a 1 × 4 AWG as the auxiliary filter with a 1 nm channel spacing. The high precision is achieved through an innovative method of decoupling three channels, involving two adjacent channels of the primary filter and one channel of the secondary auxiliary filter. Simulation results show that the AWGs have a good transmission spectrum with crosstalk below −24.8 dB, non-uniformities below 0.8 dB, insertion loss below −3.7 dB, 3 dB bandwidth of 0.25 nm, and 10 dB bandwidth of 0.43 nm. The interrogation precision can reach 8 pm, with a dynamic range of 0.4 nm, corresponding to a single FBG.