Given the 7123 working face in the Qidong Coal Mine of the Wanbei Mining Group, nine dynamic roof monitors were installed in the crossheading to measure the amount and velocity of roof convergence in different positio...Given the 7123 working face in the Qidong Coal Mine of the Wanbei Mining Group, nine dynamic roof monitors were installed in the crossheading to measure the amount and velocity of roof convergence in different positions and at different times and three steel bored stress sensors were installed in the return airway to measure rock stress at depth. On the basis of this arrange- ment, the rule of change of the distribution of the side abutment pressure with the advance of the working face and movement of overlying strata was studied. The rule of change and the stability of rock stress at depth were measured. Secondly, the affected area and stability time of the side abutment pressure were also studied. The results show that: 1) During working, the face advanced distance was from 157 m to 99 m, the process was not effected by mining induced pressure. When the distance was 82 m, the posi- tion of peak stress was 5 m away from the coal wall. When the distance was 37 m, the position of peak stress away from the coal wall was about 15 m to 20 m and finally reached a steady state; 2) the time and the range of the peak of side rock pressure obtained from stress sensors were consistent with the results from the dynamic roof monitors; 3) the position of the peak pressure was 25 m away from the coal wall.展开更多
文摘目的:分析基于降钙素原(procalcitonin,PCT)、肾动脉阻力指数(renal resistance index,RRI)、L选择素(CD62L)等实验室指标早期预测脓毒症急性肾损伤(sepsis-associated acute kidney injury,SA-AKI)的能力,为脓毒症患者急性肾损伤的早发现、早诊断、早治疗提供参考。方法:选取2020年8月—2022年5月医院收治的80例脓毒症患者作为研究对象,根据是否发生SA-AKI将患者分为发生组(n=30)和未发生组(n=50);收集患者的一般资料和CD62L、PCT、RRI水平,建立模型,分析CD62L、PCT与RRI联合检测对SA-AKI的早期预测能力。结果:发生组患者的PCT、CD62L和RRI均高于未发生组(P<0.05);PCT、CD62L、RRI联合检测预测SA-AKI的曲线下面积(area under the curve,AUC)值(0.992)高于单一预测的AUC值(0.882、0.943、0.911);且联合检测灵敏度、特异度、约登指数均高于单一检测。结论:基于PCT、CD62L、RRI等指标可较为准确地预测SA-AKI是否发生,且综合3种指标可以更准确地预知SA-AKI,从而有利于SA-AKI患者的成功救治。
基金Projects 106084 supported by the Scientific and Technological Research of the Ministry of EducationBK2007701 by the Natural Science Foundation ofJiangsu Province 2006CB2022010 by the National Basic Research Program of China and the Qing-lan Project of Jiangsu Province
文摘Given the 7123 working face in the Qidong Coal Mine of the Wanbei Mining Group, nine dynamic roof monitors were installed in the crossheading to measure the amount and velocity of roof convergence in different positions and at different times and three steel bored stress sensors were installed in the return airway to measure rock stress at depth. On the basis of this arrange- ment, the rule of change of the distribution of the side abutment pressure with the advance of the working face and movement of overlying strata was studied. The rule of change and the stability of rock stress at depth were measured. Secondly, the affected area and stability time of the side abutment pressure were also studied. The results show that: 1) During working, the face advanced distance was from 157 m to 99 m, the process was not effected by mining induced pressure. When the distance was 82 m, the posi- tion of peak stress was 5 m away from the coal wall. When the distance was 37 m, the position of peak stress away from the coal wall was about 15 m to 20 m and finally reached a steady state; 2) the time and the range of the peak of side rock pressure obtained from stress sensors were consistent with the results from the dynamic roof monitors; 3) the position of the peak pressure was 25 m away from the coal wall.
