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This paper analyzes the current research status of digital platforms for underground coal mine drilling in China from three aspects: digitization of measurement while drilling, digitization of drilling site environment monitoring, and digitization of drilling rig monitoring. Combined with the actual needs of intelligent drilling in coal mines, the overall architecture of the digital platform for directional drilling in coal mines was designed, and the connotation and path of key technologies such as multi-sensor data fusion and remote interaction were analyzed. The engineering practice of related technologies was carried out in Tianrong Coal Mine of Wuhai Mining Area, and the comprehensive management and control capability of the digital platform for drilling was verified through the trial operation system. Finally, it points out the digital development trend of directional drilling in coal mines.

The occurrence of geological hazards is the result of the interaction, constraints, and triggers of various factors. For a long time, researchers have predicted the potential locations and time (or frequency) of future geological hazards in areas prone to historical geological disasters based on environmental factors such as geology, topography, and hydrology, known as geological hazard susceptibility assessment. A prerequisite for geological hazard susceptibility assessment is the selection of impact factors, and there are dozens of factors contributing to the occurrence of geological hazards. Does the accuracy of assessment model increase with the addition of more factors? Is there an “optimal number of factors”? This simple yet crucial question is worth exploring. Taking Wenchuan County, Sichuan Province, as an example, this study selects 11 commonly used influencing factors in geological hazard susceptibility assessment and arranges them into four different combination, superimposing information from 3 to 11 factors to obtain corresponding distribution maps of geological hazard susceptibility indexes. The area under curve (AUC) value was used to evaluate the predictive accuracy of the results. Experimental results show that the prediction accuracy of the model reaches its maximum value when the number of superposition factors added to the model reaches 8 according to the preliminary set four combinations. However, during the process of factor superposition, it is found that there are certain difference between the control of susceptibility by each factor and the control determined by individual experience. When the actual factor control is arranged from largest to smallest or from smallest to largest, the predictive accuracy of the model reaches its peak value after superposition of multiple key factors. The research findings indicates that the more factors added to the geological hazard susceptibility assessment, the higher the predictive accuracy of the model. If key factors are not included during the superimposition process, the predictive accuracy of the model will not reach its peak, indicating that there is no “optimal number of factors” in geological hazard susceptibility assessment.

Because of the advantages of flexible deployment, low cable cost, strong support for mobility and comprehensive QoS control and high scalability, cellular networks had been widely used in factory scenarios.At the same time, the deterministic service in the factory also puts forward certain requirements for cellular network control.Therefore, in discussions related to 5G-Advanced, the industry also proposes to research a 5G cellular network that supports ultra-low latency.To meet the delay requirement of 2 ms, two key technologies, deterministic N3 interface and cross-layer scheduling optimization were proposed to reduce the transmission or waiting delay on the transport network and air interface.These two technologies were the enhancement based on the current communication mechanism and network protocol between cellular network and deterministic network.The high delay requirement of deterministic services can be met well without changing the existing network protocol too much.

This is an essay in the field of ceramics and composites.To achieve carbon neutrality and peaking carbon dioxide emissions, the low-iron quartz sand(\begin{document}${{ \omega }}_{{\text{Fe}}_{\text{2}}{\text{O}}_{\text{3}}}$\end{document}≤0.010%) supply for photovoltaic glass is tightening in China, so the preparation of low-iron quartz sand from quartz associated with kaolin gradually attracting widespread attention. However, quartz associated with kaolin can usually be enriched in the tailings of kaolin physical beneficiation. Taking quartz associated kaolin which is from tailings of kaolin physical beneficiation in Hepu, Guangxi as the object,the effect of purification by size fraction distribution on the preparation of low iron quartz sand from quartz-associated kaolin was studied in this essay. The experimental results showed that the index of SiO2, Al2O3 and Fe2O3 content in size of 2 mm or more was better than that of 0.71~2 mm and 0.125~0.71 mm respectively, but for all different size fraction products, ferric oxide content of quartz sand is not less than 0.016% by grinding, hydraulic classification, magnetic separation and flotation. The content of quartz sand obtained by sulfuric acid and oxalic acid was 0.0091%, and the content of quartz sand obtained by hydrofluoric acid and oxalic acid was 0.0054% respectively, both of which meets the ferric oxide content requirement of low iron quartz sand for solar photovoltaic glass and optical glass.

Objective To compare the effects of latent phase and active phase of labor analgesia with combined spinal-epidural ropivacaine and sufentanil. Methods The investigation covered 200 full-term, single-birth participants and they were randomized in to latent phase group and active phase group (100 cases each group) and received combined spinal-epidural labor analgesia when their cervices opening 0.5 cm to 2.5 cm, 3 cm respectively. VAS before analgesia and during various stages of labor, time for the first stage of labor and the second stage of labor, delivery methods,oxytocin usage, Apgar Score and maternal motor block degree were recorded and analyzed by t test, chi-square test. Results VAS before analgesia and 10 to 30 minutes after analgesia have no significant difference; VAS for the latent phase group was lower than active phase group when cervix opening 7cm to 8 cm, 10 cm after analgesia (P＜0.01); Time length for the first and the second stage of labor, delivery way, oxytocin usage, Apgar Score and maternal motor block degree were similar. Conclusions It is feasible and safe to treat latent phase labor analgesia with combined spinal-epidural ropivacaine and sufentanil.