An essential stage of mine design is an estimation of the steps of the first and periodic roof caving in longwall mines.Generally,this is carried out using the field experience and can be much enhanced by numerical si...An essential stage of mine design is an estimation of the steps of the first and periodic roof caving in longwall mines.Generally,this is carried out using the field experience and can be much enhanced by numerical simulation.In this work,the finite-difference method was applied coupled with the continuum damage mechanics(CDM)approach to simulate the stress-strain evolution of the rock mass with the underground opening during coal extraction.The steps and stages of roof caving were estimated relying on the numerical simulation data,and they were compared with the field data from several operating mines in the south of the Kuznetsk Basin,Russia.The dependence of the first roof caving step in simulation linearly correlates with field data.The results correspond to the actual roofs of longwall panels of the flat-dipping coal seams and the average rate of face advancement is approximately 5 m/day.展开更多
Using band structure parameters extracted from photoemission data by Yoshida et al., Phys. Rev. B., 2006, we have analyzed the temperature dependence of the superfluid density in overdoped La2-xSrxCuO4. We point out t...Using band structure parameters extracted from photoemission data by Yoshida et al., Phys. Rev. B., 2006, we have analyzed the temperature dependence of the superfluid density in overdoped La2-xSrxCuO4. We point out that the temperature behavior 1/λab2 is very sensitive to the ratio 2?0/kBTc and have estimated this quantity, using experimental data obtained previously by Panagopoulos et al., Phys. Rev. B., 1999. We compare the results with those obtained from NMR / NQR (Nuclear Magnetic Resonance / Nuclear Quadrupole Resonance) (Mayer et al., J. Phys, Cond. Mat., 2007) and scanning tunneling spectros-copy (Kato et al., Physica C, 2007) data.展开更多
基金This work was supported by the Russian Science Foundation,under grant 19-71-00083.Authors also would like to express gratitude to an anonymous reviewer whose comments helped to improve the quality of paper,and editors of the journal.
文摘An essential stage of mine design is an estimation of the steps of the first and periodic roof caving in longwall mines.Generally,this is carried out using the field experience and can be much enhanced by numerical simulation.In this work,the finite-difference method was applied coupled with the continuum damage mechanics(CDM)approach to simulate the stress-strain evolution of the rock mass with the underground opening during coal extraction.The steps and stages of roof caving were estimated relying on the numerical simulation data,and they were compared with the field data from several operating mines in the south of the Kuznetsk Basin,Russia.The dependence of the first roof caving step in simulation linearly correlates with field data.The results correspond to the actual roofs of longwall panels of the flat-dipping coal seams and the average rate of face advancement is approximately 5 m/day.
文摘Using band structure parameters extracted from photoemission data by Yoshida et al., Phys. Rev. B., 2006, we have analyzed the temperature dependence of the superfluid density in overdoped La2-xSrxCuO4. We point out that the temperature behavior 1/λab2 is very sensitive to the ratio 2?0/kBTc and have estimated this quantity, using experimental data obtained previously by Panagopoulos et al., Phys. Rev. B., 1999. We compare the results with those obtained from NMR / NQR (Nuclear Magnetic Resonance / Nuclear Quadrupole Resonance) (Mayer et al., J. Phys, Cond. Mat., 2007) and scanning tunneling spectros-copy (Kato et al., Physica C, 2007) data.
