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In order to evaluate the distribution characteristics and pollution risk of heavy metals in sediments of Yanhe river, we investigated the contents of the heavy metals in the sediments from 9 representative sections of the river. The index of potential ecological risk and the index of geo-accumulation were used to assess the pollution degree and the ecological risk of heavy metals in the sediment, and the Pearson correlation was used to determine the pollution sources. The results showed that the average contents of Cr, Pb, Cu, Zn, Ni, As, Cd, Hg and As in the sediments were 124.56, 98.21, 66.00, 46.20, 22.64, 4.45, 0.14 and 0.11 mg·kg-1, respectively. Among them, the average contents of Pb, Hg, Cu, Cr and Cd exceeded the environmental background values of Shaanxi Province by 5.8, 4.4, 3.2, 1.8 and 1.4 times, respectively, and the average contents of Ni, As and Zn were lower than the environmental background values of Shaanxi Province. The average of heavy metals in the sediment of Yanhe river is 303.14, with the potential ecological risk index arranged from high to low as S8>S1>S5>S7>S2>S3>S6>S9>S4, and the proportions of medium potential ecological risk and strong ecological risk is 11.1% and 88.9%, mainly caused by Hg. Meanwhile, the geo-accumulation index of Cr, Pb, Hg and Cu in the sediments is greater than 0, which is mild-moderate pollution; the geo-accumulation index of the Cd is between -0.37 and 0.11, which is no-mild pollution; and the geo-accumulation index of Ni, Zn and As are less than 0, which is no pollution. Ni, Cd and Cu in the sediments of Yanhe river have a high similarity, and industrial layout, road traffic and geological activities may be the primary sources of pollution.

Achieving faster convergence, smaller transient overshoots, and higher steady‐state tracking accuracy is essential to improve the efficiency, robustness, and applicability of robotic manipulators. This article introduces an innovative adaptive fixed‐time uniform prescribed performance controller for the manipulator facing model uncertainties and unknown disturbances. Initially, by designing a modified prescribed performance function inspired by variable superposition, this study redefines the unified prescribed performance control problem into a simplified parameter selection problem. This approach allows for the incorporation of varied performance metrics within a singular control scheme, addressing both transient and steady‐state performances concurrently without shifting control frameworks. Then, to alleviate computational demands, an adaptive neural network employing a single‐parameter weight update technique compensates for uncertainties of the manipulator dynamic model. Additionally, a disturbance observer is designed to mitigate the impact of non‐parametric disturbances. Moreover, integrating fixed‐time theory with the Lyapunov stability analysis method guarantees the convergence of all error signals to a near‐zero compact neighborhood at a fixed time. Finally, the advantages and comprehensive performance of the proposed method are confirmed by numerical simulations and real‐world experiments. [ABSTRACT FROM AUTHOR]

In this experiment, goat milk casein was used as raw material. Goat milk casein was treated with different ultrasonic intensities to explore the effects of ultrasonic treatment on the pH, conductivity, Zeta potential, turbidity and other physical and chemical indexes, as well as the functional characteristics of emulsification and foaming. The results showed that compared with untreated group, after ultrasonic treatment, the pH decreased and the conductivity had no significant change (P>0.05). The absolute value of Zeta potential reached the maximum value of 27.85±1.55 mV when treated at 400 W for 2 min. Turbidity was significantly decreased compared with untreated group (P<0.05). Ultrasonic treatment reduced the particle size of casein which reached its lowest value at 700 W treatment for 6 min, from 383.20±13.07 nm to 176.17±4.28 nm. Scanning electron microscopy results showed that ultrasound changed the original apparent morphology of casein, resulting in the formation of irregular fragments. After ultrasonic treatment, the emulsification at 100 W for 10 min was increased by 41.44%, and the foaming capacity and foaming stability of goat milk casein at 400 W for 10 min were significantly increased (P<0.05), reaching the maximum value of 32.88%±0.07% and 91.93%±0.19%, respectively. In conclusion, the cavitation effect and mechanical action produced by ultrasonic treatment can provide better physicochemical and functional properties for goat milk casein. [ABSTRACT FROM AUTHOR]

In this paper, a multi-frequency MIMO antenna for 5G and Wi-Fi 6E is presented. The antenna uses a cosine-shape monopole and split-ring resonator (SRR) structure for tri-band radiation, and frequency band expansion is achieved through SRR, folded split-ring resonators (FSRR) and Archimedean spiral metasurfaces for decoupling, with which a combination of surface wave and space wave decoupling is achieved. The Archimedean spiral metasurface unit can achieve space wave decoupling in the tri-band. By adopting the method of combining space wave decoupling and surface wave decoupling, the miniature antenna is achieved. The measured results closely align with the simulated results. Specifically, maintaining a reflection coefficient of −10 dB, the measured results indicate an increase in isolation of 3.5 dB, 36.47 dB, and 6.42 dB for the frequency bands of 3.45–3.55 GHz, 5.7–5.9 GHz, and 6.75–7 GHz, respectively. Additionally, the MIMO antenna demonstrates an average efficiency of approximately 89%, with an average envelope correlation coefficient (ECC) of 0.0025. Furthermore, the antenna's peak gain increases by 4.3 dB at 3.5 GHz, 3.8 dB at 5.8 GHz, and 1.9 dB at 6.9 GHz upon integrating the metasurface. The proposed method and structure are anticipated to contribute significantly to decoupling in multi-frequency MIMO antennas. [ABSTRACT FROM AUTHOR]