Aiming to address the following major engineering issues faced by the Pingdingshan No. 12 mine:(1) difficulty in implementing auxiliary lifting because of its depth(i.e., beyond 1000 m);(2) highly gassy main coal seam...Aiming to address the following major engineering issues faced by the Pingdingshan No. 12 mine:(1) difficulty in implementing auxiliary lifting because of its depth(i.e., beyond 1000 m);(2) highly gassy main coal seam with low permeability;(3) unstable overlying coal seam without suitable conditions for implementing conventional mining techniques for protective coal seam; and(4) predominant reliance on ‘‘under three" coal resources to ensure production output. This study proposes an integrated, closed-cycle mining-dressing-gas draining-backfilling-mining(MDGBM) technique. The proposed approach involves the mining of protective coal seam, underground dressing of coal and gangue(UDCG), pressure relief and gas drainage before extraction, and backfilling and mining of the protected coal seam. A system for draining gas and mining the protective seam in the rock stratum is designed and implemented based on the geological conditions. This system helps in realizing pressure relief and gas drainage from the protective seam before extraction. Accordingly, another system, which is connected to the existing production system, is established for the UDCG based on the dense medium-shallow trough process. The mixed mining workface is designed to accommodate both solid backfill and conventional fully mechanized coal mining, thereby facilitating coal mining, USCG, and backfilling. The results show that: The mixed mining workface length for the Ji15-31010 protected seam was 220 m with coal production capacity 1.2 million tons per year, while the backfill capacity of gangue was 0.5 million tons per year. The gas pressure decreased from 1.78 to 0.35 MPa, and the total amount of safely mined coal was 1.34 million tons. The process of simultaneously exploiting coal and draining gas was found to be safe, efficient, and green.This process also yielded significant economic benefits.展开更多
Objective: To investigate the insomnia incidence and treatment status of military retired cadres and offer an instruction for their health care. Methods: We designed a questionnaires composed of general information, h...Objective: To investigate the insomnia incidence and treatment status of military retired cadres and offer an instruction for their health care. Methods: We designed a questionnaires composed of general information, health-related factors, diseases, etc. Insomnia manifestations included regular sleep time, shorten sleep time and extent, time of falling asleep, sleep quality, difficultly returning to sleep after awakening at mid-night, insomnia time, etc. Results: A total of 4759 questionnaires (94.2%) were reclaimed. Dyssomnia was found in 1843 persons (38.7%), including 1006 cases of transient insomnia (44.0%) and 837 cases of acute insomnia (36.6%). Conclusion: About one third of the examined military retired cadres have sleep problems, so they should enhance the health care consciousness and receive proper nurse and treatment.展开更多
基金supported by the Qing Lan Project Foundation of Jiangsu Province in 2014,Foundation for Distinguished professor of Jiangsu Province in 2015,Science Fund for Creative Research Groups of the National Natural Science Foundation of China(No.51421003)Project funded by China Postdoctoral Science Foundation(2016M601915)National Key Basic Research Program of China(No.2013CB227905)
文摘Aiming to address the following major engineering issues faced by the Pingdingshan No. 12 mine:(1) difficulty in implementing auxiliary lifting because of its depth(i.e., beyond 1000 m);(2) highly gassy main coal seam with low permeability;(3) unstable overlying coal seam without suitable conditions for implementing conventional mining techniques for protective coal seam; and(4) predominant reliance on ‘‘under three" coal resources to ensure production output. This study proposes an integrated, closed-cycle mining-dressing-gas draining-backfilling-mining(MDGBM) technique. The proposed approach involves the mining of protective coal seam, underground dressing of coal and gangue(UDCG), pressure relief and gas drainage before extraction, and backfilling and mining of the protected coal seam. A system for draining gas and mining the protective seam in the rock stratum is designed and implemented based on the geological conditions. This system helps in realizing pressure relief and gas drainage from the protective seam before extraction. Accordingly, another system, which is connected to the existing production system, is established for the UDCG based on the dense medium-shallow trough process. The mixed mining workface is designed to accommodate both solid backfill and conventional fully mechanized coal mining, thereby facilitating coal mining, USCG, and backfilling. The results show that: The mixed mining workface length for the Ji15-31010 protected seam was 220 m with coal production capacity 1.2 million tons per year, while the backfill capacity of gangue was 0.5 million tons per year. The gas pressure decreased from 1.78 to 0.35 MPa, and the total amount of safely mined coal was 1.34 million tons. The process of simultaneously exploiting coal and draining gas was found to be safe, efficient, and green.This process also yielded significant economic benefits.
文摘Objective: To investigate the insomnia incidence and treatment status of military retired cadres and offer an instruction for their health care. Methods: We designed a questionnaires composed of general information, health-related factors, diseases, etc. Insomnia manifestations included regular sleep time, shorten sleep time and extent, time of falling asleep, sleep quality, difficultly returning to sleep after awakening at mid-night, insomnia time, etc. Results: A total of 4759 questionnaires (94.2%) were reclaimed. Dyssomnia was found in 1843 persons (38.7%), including 1006 cases of transient insomnia (44.0%) and 837 cases of acute insomnia (36.6%). Conclusion: About one third of the examined military retired cadres have sleep problems, so they should enhance the health care consciousness and receive proper nurse and treatment.
