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The in-situ liquid injection leaching process of ionized rare earth is a typical process of effusion infiltration, and the infiltration efficiency directly determines the mining efficiency. Assuming that the infiltrated (NH4)2SO4 solution is uniformly distributed in the homogeneous orebody, the relationships between the following groups are derived and studied: (1) The position and time of the infiltration front; (2) The infiltration intensity and the infiltration time; (3) The advancing speed and time of the infiltration front.A wireless network sensor detection system for parameter detection is established based on 4G network,air pressure sensor and water sensor are embedded in the ore body.The sensors are connected to the terminal via the 4G network,the data collection and wireless transmission of water content change and air pressure change of one-imensional fluid infiltration test in the homogeneous ore body with different compaction density were completed by the proposed wireless network sensor detection system. The results show that the influence of residual air pressure can be ignored during the infiltration;the advancing speed of the infiltration front is the fastest at the beginning, and then gradually decreased and stabilized; the change process of infiltration volume corresponds to the process of infiltration front advancing speed; the higher the density, the slower the advancing speed of the infiltration front, the lower the infiltration intensity, and the more difficult the infiltration; the deduced theory can be in good agreement with the actual infiltration situation with high accuracy, which can effectively simulate the infiltration process of ionized rare earth in-situ liquid injection mining.

Considering the development of the hybrid wind and solar photovoltaic generation and smart grid, Active Front-End (AFE) converters for high-power applications are facing significant opportunities and challenges related to power quality and efficiency. The Pre-programmed Pulse-Width Modulation (PPWM) techniques can strictly control the harmonic spectrum of a specified voltage or current waveform generated by a high-power AFE converters, and have been extensively applied to reduce or even eliminate the harmonic distortion with low switching losses for high-power converters in order to deal with these issues aforementioned. For the PPWM techniques with low switching frequency, Selective Harmonic Elimination (SHE) and Selective Harmonic Mitigation (SHM) have been the prevailing solutions and gain widespread popularity, among which SHM can provide further control of the harmonic spectrum in cases of similar switching losses to SHE. Over the past several decades, the applications of SHE and SHM have been extended to high-power AFE converters. Thus, the aim of this study is to provide a comprehensive literature review regarding their various formulations, solving algorithms, and existing problems to high-power AFE converters. In addition, the suggestions for future applications of PPWM in high-power AFE converters are also discussed.