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The underwater streamer discharges have a variety of potential applications in environmental science and technology. The electrical characteristics of the plasma filament generated by underwater streamer discharges play an important role in its propagation through water and influence the production of the chemical reactive species and the energy injected into the plasma filament. In this paper, we studied the electric field inside the plasma filament, the electric field at the head of the plasma filament, and the electrical conductivity of the plasma filament. By measuring the maximum length and the radius of the plasma filament, we found that the linear relation between the maximum length of the plasma filament and the applied voltage is not affected by the water conductivity within the range of 60–540 μS/cm. Based on such kind of linear relation, the electric field inside the plasma filament and the electric field at the head of the plasma filament were estimated as 26.0 ± 1.2 and 372 ± 52 kV/cm on average, respectively, being independent of the water conductivity within the range of 60–540 μS/cm. The electrical conductivity of the plasma filament was 0.4–3.7 S/cm within the range studied, being 3–4 orders of magnitude greater than that of the ambient water and depending significantly on the water conductivity. The experimental data obtained in the present work will be beneficial for the design of the reactor of pulsed underwater discharges. [ABSTRACT FROM AUTHOR]

Mesotrione (MET) belongs to the p-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting class of maize post-emergence herbicides, and it is safe for maize at the recommended doses, but the safety of MET differs among maize varieties in actual field production. In this study, four different maize varieties, ZD958, SN3, ST6 and POP16, were used as experimental materials to analyze their physiological responses to MET by comparing the activities of photosynthesis and antioxidant enzymes as well as the HPPD activity. The results showed that ZD958 was the most resistant to MET, followed by SN3 and ST6, and POP16 was the most sensitive to MET. The primary photosynthetic and antioxidant enzyme indices of all four maize varieties indicated that the resistant variety ZD958 was significantly higher than the sensitive variety POP16. HPPD activity was highest in ZD958 followed by SN3 and ST6 in both treated and control groups. POP16 exhibited the lowest HPPD activity. The results showed that the differences in resistance to MET in different types of maize varieties were closely related to the photosynthetic efficiency of plants and the HPPD activity. MET had minimal impact on common maize but showed a significant effect on popcorn. [ABSTRACT FROM AUTHOR]

To reduce the influence of temperature on difluoromethane (R32) gas sensors using non-dispersive infrared (NDIR), a temperature compensation method based on improved whale optimization algorithm (IWOA) and back propagation neural network (BPNN) is proposed. The IWOA that uses tent chaotic mapping to optimize the initial population of the whale optimization algorithm (WOA) and incorporates adaptive weights in the population iterations is used to optimize the weights and thresholds between nodes in each layer of the BPNN. The optimized BPNN is used to train the temperature compensation model. The experimental results show that the back propagation neural network optimized with improved whale optimization algorithm (IWOA-BPNN) reduces the maximum relative error to 1.33%, compared to 12.46 and 11.66% for the traditional BPNN and the back propagation neural network optimized with whale optimization algorithm (WOA-BPNN), respectively. IWOA-BPNN is also compared with previously reported algorithms, and the results show that the algorithm improves the accuracy of the sensor. [ABSTRACT FROM AUTHOR]

Highlights: An efficient moist-electric generator with ultra-fast electric response to moisture is achieved by triggering Grotthuss protons hopping in the moisture-electric–moisture-sensitive heterostructure. The moist-electric generator produces a quick response (0.435 s), an unprecedented ultra-fast response rate of 972.4 mV s−1 to alternating moisture stimulation and stable output for 8 h. An obstructive sleep apnea hypoventilation syndrome diagnostic system based on a moist-electric generator was developed to monitor hypopnea and apnea in real time and successfully diagnose them with early warning. Moisture-enabled electricity (ME) is a method of converting the potential energy of water in the external environment into electrical energy through the interaction of functional materials with water molecules and can be directly applied to energy harvesting and signal expression. However, ME can be unreliable in numerous applications due to its sluggish response to moisture, thus sacrificing the value of fast energy harvesting and highly accurate information representation. Here, by constructing a moisture-electric–moisture-sensitive (ME-MS) heterostructure, we develop an efficient ME generator with ultra-fast electric response to moisture achieved by triggering Grotthuss protons hopping in the sensitized ZnO, which modulates the heterostructure built-in interfacial potential, enables quick response (0.435 s), an unprecedented ultra-fast response rate of 972.4 mV s−1, and a durable electrical signal output for 8 h without any attenuation. Our research provides an efficient way to generate electricity and important insight for a deeper understanding of the mechanisms of moisture-generated carrier migration in ME generator, which has a more comprehensive working scene and can serve as a typical model for human health monitoring and smart medical electronics design. [ABSTRACT FROM AUTHOR]