In deep underground mining, the surrounding rocks are very soft with high stress. Their deformation and destruction are serious, and frequent failures occur on the bolt support. The failure mechanism of bolt support i...In deep underground mining, the surrounding rocks are very soft with high stress. Their deformation and destruction are serious, and frequent failures occur on the bolt support. The failure mechanism of bolt support is proposed to solve these problems. A calculation theory is established on the bond strength of the interface between the anchoring agent and surrounding rocks. An analysis is made on the influence law of different mechanical parameters of surrounding rocks on the interfacial bond strength. Based on the research, a new high-strength bolt-grouting technology is developed and applied on site. Besides, some helpful engineering suggestions and measures are proposed. The research shows that the serious deformation and failure, and the lower bond strength are the major factors causing frequent failures of bolt support. So, the bolt could not give full play to its supporting potential. It is also shown that as the integrity, strength, interface dilatancy and stress of surrounding rocks are improved, the bond strength will increase. So, the anchoring force on surrounding rocks can be effectively improved by employing an anchoring agent with high sand content, mechanical anchoring means, or grouting reinforcement. The new technology has advantages in a high strength, imposing pre-tightening force, and giving full play to the bolt supporting potential. Hence, it can improve the control effect on surrounding rocks. All these could be helpful references for the design of bolt support in deep underground mines.展开更多
In the present study, we developed a sensitive and efficient high performance liquid chromatography （HPLC） method for the simultaneous determination of three ginsenosides （Rg1, Re, Rb1） in rat plasma. Chromatograp...In the present study, we developed a sensitive and efficient high performance liquid chromatography （HPLC） method for the simultaneous determination of three ginsenosides （Rg1, Re, Rb1） in rat plasma. Chromatographic separation was performed on a C18 （150 min×4.6 mm） column utilizing gradient elution profile and a mobile phase consisting of （A） water and （B） acetonitrile. The calibration curve, with a great correlation coefficient greater than 0.998, was linear over the range of 1.0-30.0 μg/mL for ginsenoside Rgl, 0.5-15.0 μg/mL for ginsenoside Re, and 0.5-200.0 μg/mL for ginsenoside Rb1. The intra- and inter-day precisions for three ginsenosides （Rg1, Re, Rb1） were all less than 6.0%, and average recovery, examined at three concentration levels, ranged from 96.1% to 118.6%. The samples was stable within 24 h at 4 ℃ storage, and 30 d at -20 ℃ storage with three freeze-thaw-assay cycles. The low limits of quantification （LOQ） were 1.0, 0.5 and 0.5 μg/mL for Rg1, Re and Rb1, respectively. Taken together, the newly developed method was successfully applied to study the pharmacokinetics of ginsenoside Rg1, Re and Rb1 in rat plasma after intravenous administration of SHENMAI injection （SMI）.展开更多
基金Projects(51304125,51379114)supported by the National Natural Science Foundation of ChinaProject(BS2013NJ004)supported by Award Fund for Outstanding Young and Middle-Aged Scientist of Shangdong Province,ChinaProject(201301004)supported by the Innovation Fund for Postdoctor of Shandong Province,China
文摘In deep underground mining, the surrounding rocks are very soft with high stress. Their deformation and destruction are serious, and frequent failures occur on the bolt support. The failure mechanism of bolt support is proposed to solve these problems. A calculation theory is established on the bond strength of the interface between the anchoring agent and surrounding rocks. An analysis is made on the influence law of different mechanical parameters of surrounding rocks on the interfacial bond strength. Based on the research, a new high-strength bolt-grouting technology is developed and applied on site. Besides, some helpful engineering suggestions and measures are proposed. The research shows that the serious deformation and failure, and the lower bond strength are the major factors causing frequent failures of bolt support. So, the bolt could not give full play to its supporting potential. It is also shown that as the integrity, strength, interface dilatancy and stress of surrounding rocks are improved, the bond strength will increase. So, the anchoring force on surrounding rocks can be effectively improved by employing an anchoring agent with high sand content, mechanical anchoring means, or grouting reinforcement. The new technology has advantages in a high strength, imposing pre-tightening force, and giving full play to the bolt supporting potential. Hence, it can improve the control effect on surrounding rocks. All these could be helpful references for the design of bolt support in deep underground mines.
基金Science and Technology Research project of Heilongjiang Province Department of Education(Grant No.12541740)
文摘In the present study, we developed a sensitive and efficient high performance liquid chromatography （HPLC） method for the simultaneous determination of three ginsenosides （Rg1, Re, Rb1） in rat plasma. Chromatographic separation was performed on a C18 （150 min×4.6 mm） column utilizing gradient elution profile and a mobile phase consisting of （A） water and （B） acetonitrile. The calibration curve, with a great correlation coefficient greater than 0.998, was linear over the range of 1.0-30.0 μg/mL for ginsenoside Rgl, 0.5-15.0 μg/mL for ginsenoside Re, and 0.5-200.0 μg/mL for ginsenoside Rb1. The intra- and inter-day precisions for three ginsenosides （Rg1, Re, Rb1） were all less than 6.0%, and average recovery, examined at three concentration levels, ranged from 96.1% to 118.6%. The samples was stable within 24 h at 4 ℃ storage, and 30 d at -20 ℃ storage with three freeze-thaw-assay cycles. The low limits of quantification （LOQ） were 1.0, 0.5 and 0.5 μg/mL for Rg1, Re and Rb1, respectively. Taken together, the newly developed method was successfully applied to study the pharmacokinetics of ginsenoside Rg1, Re and Rb1 in rat plasma after intravenous administration of SHENMAI injection （SMI）.
