The Co₃S₄@NiCo-LDH/NF nanocomposite exhibits outstanding electrocatalytic performances toward both the HER and OER at high current densities, along with a remarkable durability.

In this paper, we proposed a dynamic modulation band rejection filter based on the spoof surface plasmon polaritons (SSPPs) waveguide. The dynamic adjusting mainly derives from changing the capacitance between the U-shape and the waveguide configuration. The capacitance can modulate the cut-off frequency of fundamental mode. The rejection band is formed by the high order propagation mode and the cut-off frequency of fundamental mode. We analyzed the dispersion curve and transmission performance of the band rejection filter with different capacitances. Compared with the previous scheme, the design we proposed here has a simpler and more delicate configuration to process and decreases the mechanical error. We experimentally demonstrated the excellent performance of the device by changing the direct voltage loaded on the varactor diode and achieved real time modulation around 2 GHz.

In this study, an advanced wireless power transfer (WPT) system of two coils with the artificial magnetic conductors (AMC) is explored through simulations and experiments. The AMC structure is added on the transmitter coil, and the multiple resonant modes on the surface of the AMC can be energized. On the other hand, the AMC structure act as a magnetic field shield, which leads to the magnetic field above AMC structure is localized. Therefore, the localized resonant magnetic field enhance the transmission coefficient of the WPT system. The results show that the WPT transmission coefficient is increased from 16% to 35% in the experiment at 26.2 MHz resonant frequency when transmission distance is 3 cm. The experimental results agree with the simulation results. Additionally, AMC has the advantages of low-cost and can easily be installed on the WPT system.

The challenge in using fully mechanized caving mining technology for thick coal seam mining is monitoring the mixing ratio of coal gangue during the top coal caving process. In this paper, we propose a passive wireless sensing system based on the second-order parity-time symmetric system operated around the exceptional point for the monitoring of coal gangue mixing, which has an LC resonance structure consisting of a spiral resonant coil and a parallel-plate capacitor at the wireless sensing end of the system. The parallel capacitor was designed as a sampling platform. When different proportions of the coal gangue mixture are placed on it, the capacitance value of the capacitor changes, changing the resonance frequency of the system. Our results indicated that the passive wireless sensing system could clearly distinguish the degree of mixing of the coal and gangue and has a higher sensitivity than the conventional system. The proposed system was compared with a mosquito resonant coil system of the same order, and the results indicated that the spiral resonant coil wireless sensing system has more significant advantages in the enhancement of sensitivity. This passive wireless sensing system provides an accurate method for the automatic identification of coal gangue in the top coal caving process; furthermore, it is inexpensive and highly operable.

In this paper, we propose a scheme for subwavelength electromagnetic diodes by employing a photonic crystal (PC) cavity with embedded electromagnetically induced-transparency (EIT)-like highly dispersive meta-interface. A nonreciprocal response, with 21.5 dB transmission light contrast and 12.3 dBm working power, is conceptually demonstrated in a microstrip transmission line system with asymmetric absorption and nonlinear medium inclusion. Such high-contrast transmission and relatively low-threshold diode action stem from the composite PC-EIT mechanism. This mechanism not only possesses a large quality factor and strong localization of fields but also does not enlarge the device volume and drastically reduce transmittance. Our findings should be beneficial for the design of new and practical metamaterial-enabled nonlinear devices.