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In order to improve performance of battery electric locomotive in coal mine, reduce energy consumption and improve work efficiency, a kind of control system of mine-used switched reluctance electric locomotive based on ARM was designed. The system uses control mode combing angular position control and chopped voltage control, adopts control strategy of torque distribution function, and achieves control of the battery motor vehicle combined with speed and current dual closed-loop system. The experimental results show that the system has small torque ripple, high efficiency, strong robustness and good performance of speed adjustment.

To better understand the influence of aerosols on micro-properties of clouds and to facilitate weather modification experiments including the analysis of various materials' seeding effect on clouds and precipitation, Beijing Weather Modification Center has taken a decisive step forward by constructing an advanced facility known as Beijing aerosol and cloud interaction chamber (BACIC) in suburban Pinggu district. Boasting an impressive volume of 70 m3, BACIC is not only the largest of its kind in operation in China, but also a testament to the scale of the country's commitment to this sphere of atmospheric science. The enormity of the chamber's capacity facilitates the performance of a broad spectrum of investigations, thus enhancing the comprehensiveness and reliability of the results obtained.Inside BACIC, advanced instrumentation allows for the meticulous measurement and control of temperature, relative humidity, and background aerosol concentration. During 2019-2021, the chamber's capabilities extend further, as demonstrated by successful tests of its ability to create liquid and mixed-phase clouds. These attributes, combined with its capacity to control the cloud droplet size distribution as proved by comparative experiments involving changes in expansion rate and aerosol number concentration, solidify BACIC's standing as a prime location for warm cloud experimentation. The chamber has also been utilized to investigate effects of anthropogenic pollution over North China Plain (NCP) on cloud microphysics. Using ambient air and manipulating the expansion rate, a significant correlation is discovered between such pollution and the size distribution of cloud droplets. Interestingly, while an increase in aerosol leads to higher number of cloud droplets, it also causes a decrease in droplet size, typically within the range of 5-8 μm. Furthermore, an increase in aerosol number concentration leads to a decrease in the activation rate of aerosols into cloud droplets. This activation rate is around 10% for aerosol concentrations less than 5000 cm-3, and remains stable even when the aerosol concentration increases to 10000 cm-3.BACIC is also proved useful in conducting warm cloud expansion experiments involving different hygroscopic materials. It shows that the distribution of submicron (less than 1 μm) hygroscopic catalysts in a polluted environment leads to narrowing of the cloud droplet spectrum. It suggests that for the purpose of artificially reducing warm clouds or fog, it is recommended to use larger particle sizes. The results obtained from these diverse series of experiments have significantly contributed to theoretical knowledge and provide practical guidance for the ongoing development of artificial weather modification techniques.

[Introduction] To fill the shortcomings of traditional on-line power quality monitoring system, such as high deployment cost, large maintenance workload, low coverage and single function, which are highlighted under the higher requirement of information and intellectualization for the rapid development of UHV grid and new energy grid-connected technology. [Method] A method of identifying, extracting and calculating power quality characteristic parameters based on fault recorder data mining was proposed, and a system architecture of non-intrusive power quality monitoring, evaluation and decision support for wide area power grid using existing recorders and dispatching data network was designed. [Result] The results of pilot application show that the power quality indicators monitored by the system are comprehensive, the acquisition accuracy is better than the standard requirements, and the accuracy of event recognition and diagnosis is high. It has obvious advantages in station coverage, capacity of monitoring points, file upload, early warning and information delivery. [Conclusion] The design of the system is feasible and can extend and supplement the existing power quality online monitoring system in wide area power grid with a small input.

Based on the general relationship described by Cheng between the drag coefficient and the Reynolds number of a particle, a new relationship between the Reynolds number and a dimensionless particle parameter is proposed. Using a trial-and-error procedure to minimize errors, the coefficients were determined and a formula was developed for predicting the settling velocity of natural sediment particles. This formula has higher prediction accuracy than other published formulas and it is applicable to all Reynolds numbers less than 2×105.

Based on the general relationship described by Cheng between the drag coefficient and the Reynolds number of a particle, a new relationship between the Reynolds number and a dimensionless particle parameter is proposed. Using a trial-and-error procedure to minimize errors, the coefficients were determined and a formula was developed for predicting the settling velocity of natural sediment particles. This formula has higher prediction accuracy than other published formulas and it is applicable to all Reynolds numbers less than 2×105.