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Aiming at the problems of inaccurate judgment of linear range and the inability to measure dynamically of traditional compliance measuring instrument of loudspeaker spider，a spider compliance measurement system based on STM32 was designed. In the hardware design, the function of auto-measurement was realized by motion control circuit and data acquisition circuit, and a low voltage ripple DC voltage regulator was used to make the sampling result more accurate. In the part of the software design, the sliding mean filter algorithm was used to reduce the output error, the least square algorithm was used to improve the fitting goodness, and the linear approximation was used to obtain the linear range of the spider. The experiments show that the resolution of the system is high, the compliance curve and the linear range of the spider can be obtained accurately.

The development of photocatalysts with a wide spectral response and effective carrier separation capability is essential for the green degradation of tetracycline hydrochloride. In this study, a magnetic recyclable Z-scheme ZnO/ZnFe2O4 heterojunction (ZZF) was successfully constructed via the solid phase method, using MIL-88A(Fe)@Zn as the precursor. An appropriate band gap width and Z-scheme charge transfer mechanism provide ZZF with excellent visible light absorption performance, efficient charge separation, and a strong redox ability. Under visible light irradiation, the degradation efficiency of tetracycline hydrochloride for the optimal sample can reach 86.3% within 75 min in deionized water and 92.9% within 60 min in tap water, exhibiting superior stability and reusability after five cycles. Moreover, the catalyst in the water can be conveniently recovered by magnetic force. After visible light irradiation for 70 min, the temperature of the reaction system increased by 21.9 °C. Its degradation constant (35.53 × 10−3 min−1) increased to 5.1 times that at room temperature (6.95 × 10−3 min−1). Using thermal energy enhances the kinetic driving force of the reactants and facilitates carrier migration, meaning that more charge is available for the production of •O2− and •OH. This study provides a potential candidate for the efficient degradation of tetracycline hydrochloride by combining thermal catalysis with a photocatalytic heterojunction. [ABSTRACT FROM AUTHOR]

Rational design of a hierarchical core–shell structured photocatalyst is crucial for enhancing the separation and transport efficiency of photogenerated carriers, thereby improving the photocatalytic degradation efficiency. In this study, hollow polyhedral CoSx was first synthesized by utilizing dodecahedral Co-based metal–organic framework (ZIF-67) as a Co source and template, followed by introducing In and S species to fabricate hierarchical core–shell In2S3/CoSx composites. The resulting In2S3/CoSx porous hollow heterostructured composites exhibited an accelerated interfacial carrier transfer ratio and enhanced photocatalytic removal performance of tetracycline hydrochloride (TCH). Among them, the optimized sample In2S3/CoSx-2 (CoIS-2) demonstrated the highest TCH removal rate of 0.0324 min–1, which was 22.8 times higher than that of pristine CoSx and 5.7 times higher than that of pure In2S3, respectively. Moreover, its apparent quantum efficiency reached 4.66% at 420 nm. Electron spin resonance analysis and active substance capture experiments confirmed that superoxide radical (•O2–) played a predominant role in the reaction system. Furthermore, we investigated the dynamics of photoinduced carriers through a series of photoelectric tests combined with density functional theory calculations. This study provides valuable insights into controllable construction of metal–organic framework-based materials with high photocatalytic degradation efficiency and stability. [ABSTRACT FROM AUTHOR]