Interdigital transducer and signal transmission in surface acoustic wave pressure sensor design is one of the difficulties in sensor design. The transmission antenna is an important design indicator to determine the wireless function of the sensor. In this paper, we simulated the design of the interdigital transducer of surface acoustic wave pressure sensor through COMSOL and analyzed the relationship between the eigenfrequency of the single-pair interdigital model and the interdigital electrode. Then, we obtained the design of the interdigital electrode with error of 0.01 MHz. We also simulated the size, bandwidth, impedance matching, and other parameters of antenna through high frequency structure simulator, and a matching dipole transmission antenna was designed and miniaturized. When the bandwidth is satisfied, the control matching impedance error is within [Formula: see text], and it is verified that the antenna satisfies the signal transmission requirement of the surface acoustic wave pressure sensor. This design provides a more comprehensive approach to the design of interdigital transducers and signal transmission for the field of surface acoustic wave measurement pressure.

Shear horizontal surface acoustic wave (SH-SAW) sensors have great application potential due to their advantages of easy integration, miniaturization and suitability in liquid environments. In this paper, the finite element method is used to analyse a new SH-SAW micro pressure sensor, in which there are many groove structures along the direction of wave propagation on the delay path. We use the transient response simulation method to calculate and analyse the output voltage signal at the output interdigital transducer and surface average stress at the delay path of this new SH-SAW sensor, and its pressure sensitivity is analysed by uniformly applying an appropriate surface pressure on the resonant beam formed after grooving. The simulation results show that the surface average stress can be enhanced in a certain range of groove depth during the vibration of the groove structure. When the groove depth and width are set to 0.7 μm and 0.5 μm, respectively, the sensitivity of the SH-SAW sensor with a groove structure is four times higher than that of the traditional SH-SAW sensor. The increase of pressure sensitivity is the result of the increase of average stress caused by the groove structure. The new groove structure SH-SAW sensor provides a new basis for research on high-sensitivity micro-pressure sensors and lays a foundation for subsequent device design and manufacture.

At present, binary bimetallic sulfides are widely studied in supercapacitors due to their high conductivity and excellent specific capacitance (SC). In this article, NiCo-S nanostructured hybrid electrode materials were prepared on nickel foam (NF) by using a binary metal–organic skeleton as the sacrificial template via a two-step hydrothermal method. Comparative analysis was carried out with Ni-S and Co-S in situ on NF to verify the excellent electrochemical performance of bimetallic sulfide as an electrode material for supercapacitors. NiCo-S/NF exhibited an SC of 2081 F∙g−1 at 1 A∙g−1, significantly superior to Ni-S/NF (1520.8 F∙g−1 at 1 A∙g−1) and Co-S/NF (1427 F∙g−1 at 1 A∙g−1). In addition, the material demonstrated better rate performance and cycle stability, with a specific capacity retention rate of 58% at 10 A∙g−1 than at 1 A∙g−1, and 75.7% of capacity was retained after 5000 cycles. The hybrid supercapacitor assembled by NiCo-S//AC exhibited a high energy density of 25.58 Wh∙kg−1 at a power density of 400 W∙kg−1.

The inability to extract spatial axis and radial multi-error coupling phenomenon exists in the process of axial profile reconstruction, which is essentially a first harmonic suppression problem as well as a multi-error decoupling problem. In this paper, a four-probe system is constructed based on an L-shaped arrangement in two adjacent planes. First, the mathematical model of the first harmonic suppression problem of the shaft system is established in the first plane, and the first harmonic component of roundness error is used as the axial reference for reconstructing the profile, and the value of the first-order harmonic component is solved by theoretical derivation, and the spatial axis of the reconstructed shaft system profile is fitted with it, which proves the correctness of the established mathematical model by the data simulation. Then, the radial mixed error detection is carried out in two adjacent planes in the axial direction, and the results measured at the two measurement positions are analyzed theoretically to obtain the tilt error decoupling formula. It breaks through the limitation that the error separation online detection cannot be performed in the standard ball measurement method. The experiment verifies that the accuracy of the spatial axis is improved by up to 0.5 μm after decoupling the tilt error, and the accuracy of the reconstructed circularity profile of a single section is improved by up to 2.657 mm. In the comparison experiment with the standard ball measurement method, the difference of the measured roundness error between the two methods does not exceed 1.2 μm, which proves that the online inspection method proposed in this paper can guarantee the accuracy of the reconstructing circularity profile.

THz (terahertz) properties of MgF2 crystal (sample 1) and MgF2: Co crystal (sample 2) is measured using transmission THz time domain spectroscopy in the frequency range between 0.5 and 2.5 THz. The absorption coefficients α(ν) of sample 1 increases and has a maximum 24cm-1 with increasing frequency ν from 0.5　THz to 2.5　THz. The absorption coefficient of sample 2 is much larger than that of the sample 1, and its absorption band edge of the crystal lattice shifts to lower frequency side because of the dopant Co. Moreover, there is an absorption peak at 1.9THz and the absorption coefficient is greater than 70 cm-1, the force constant K of F-—Co2+ ionic chemical bond stretch vibration calculated from this peak is 3.40×10-2　N/cm. The THz spectroscopy can be an important technique for research of chemical bond in crystal. Real dielectric functions between 0.5 and 2.5 THz of the two samples are calculated by relations between optical constants. The ε1(ν) of sample 1 varies from 4.67 to 4.73 and ε1(ν) of sample 2 varies from 4.62 to 5.01.

Honeycomb-like Ni(OH)2/Ni3S2/Ni foam (NF) was fabricated via a two-step hydrothermal process and subsequent alkalization. Ni3S2 with a honeycombed structure was in-situ synthesized on the NF surface by a hydrothermal process. MOF-derived Ni(OH)2 nanosheets were then successfully grown on the Ni3S2/NF surface by a second hydrothermal process and alkaline treatment, and a large number of nanosheets were interconnected to form a typical honeycomb-like structure with a large specific surface area and porosity. As a binder-free electrode, the prepared honeycomb-like Ni(OH)2/Ni3S2/NF exhibited a high specific capacitance (2207 F·g−1 at 1 A·g−1, 1929.7 F·g−1 at 5 mV·s−1) and a remarkable rate capability and cycling stability, with 62.3% of the initial value (1 A·g−1) retained at 10 A·g−1 and 90.4% of the initial value (first circle at 50 mV·s−1) retained after 5000 cycles. A hybrid supercapacitor (HSC) was assembled with Ni(OH)2/Ni3S2/NF as the positive electrode and activated carbon (AC) as the negative electrode and exhibited an outstanding energy density of 24.5 Wh·kg−1 at the power density of 375 W·kg−1. These encouraging results render the electrode a potential candidate for energy storage.