A test system was designed by using a set of self-made experimental devicesof coupled coal-gas in simulating mining stress effect, combining the equipment withRMT-150B rock mechanical experimental system, monitoring t...A test system was designed by using a set of self-made experimental devicesof coupled coal-gas in simulating mining stress effect, combining the equipment withRMT-150B rock mechanical experimental system, monitoring the rupture process ofcoal-rock with an acoustic emission (AE) device and collecting gas-flow rate andgas-stress data in real-time automatically with a gas flow-meter and gas pressure sensor.The fracture process and permeability properties test of the coal-rock in mining stress effect was carried out. Test results indicate that AE events and variation of stresses have thesame variance tendency and the rupture process of coal-rock can be monitored by AE.The relation curves among stresses, parameters of AE and permeability properties demonstrate that the permeability of coal-rock decreases gradually at quasi-elastic stage, increases gradually at plastic damage micro-fracture stage, rises suddenly near the peakpoint and has multi-variation at post-peak slip stage. From the results, such conclusioncan be drawn that the variation of permeability can be monitored by AE parameters orstress change.展开更多
Self-assembly of silicon nanowire(SiNW)arrays is studied using SF_(6)/0_(2)plasma treatment.The self-assembly method can be applied to single-and poly-crystalline Si substrates.Plasma conditions can control the length...Self-assembly of silicon nanowire(SiNW)arrays is studied using SF_(6)/0_(2)plasma treatment.The self-assembly method can be applied to single-and poly-crystalline Si substrates.Plasma conditions can control the length and diameter of the SiNW arrays.Lower reflectance of the wire arrays over the wavelength range 200-1100nm is obtained.The conducting transparent indium-tin-oxide(ITO)electrode can be fully coated on the self-assembled SiNW arrays by sputtering.The ITO-coated SiNW solar cells show the same low surface light reflectance and a higher carrier collection efficiency than SiNW solar cells without ITO coating.An efficiency enhancement of around 3 times for ITO coated SiNW solar cells is demonstrated via experiments.展开更多
Based on simulated material scale modeling and numerical simulation, the protective seam mining method was conducted at one coal mine. After extracting the No.15seam, the overlying strata movement and the deformation ...Based on simulated material scale modeling and numerical simulation, the protective seam mining method was conducted at one coal mine. After extracting the No.15seam, the overlying strata movement and the deformation of the No.9-10 protected seamwere studied. The experiment results show that it is feasible to destress the protectedseams with large interburden thickness. When the face had advanced 200 m from thesetup room, the No.9-10 seam was fully destressed, resulting in easy gas drainage in thedestressed zone. Recommendations on mining sequence of multiple seams mining in thesame coal areas were made.展开更多
基金Supported by Significant Public Welfare Project of Henan Province (08110091500)the Research Fund for the Doctoral Program of Higher Education(20070460001 )National Nature Science Foundation of China(50478061)
文摘A test system was designed by using a set of self-made experimental devicesof coupled coal-gas in simulating mining stress effect, combining the equipment withRMT-150B rock mechanical experimental system, monitoring the rupture process ofcoal-rock with an acoustic emission (AE) device and collecting gas-flow rate andgas-stress data in real-time automatically with a gas flow-meter and gas pressure sensor.The fracture process and permeability properties test of the coal-rock in mining stress effect was carried out. Test results indicate that AE events and variation of stresses have thesame variance tendency and the rupture process of coal-rock can be monitored by AE.The relation curves among stresses, parameters of AE and permeability properties demonstrate that the permeability of coal-rock decreases gradually at quasi-elastic stage, increases gradually at plastic damage micro-fracture stage, rises suddenly near the peakpoint and has multi-variation at post-peak slip stage. From the results, such conclusioncan be drawn that the variation of permeability can be monitored by AE parameters orstress change.
文摘Self-assembly of silicon nanowire(SiNW)arrays is studied using SF_(6)/0_(2)plasma treatment.The self-assembly method can be applied to single-and poly-crystalline Si substrates.Plasma conditions can control the length and diameter of the SiNW arrays.Lower reflectance of the wire arrays over the wavelength range 200-1100nm is obtained.The conducting transparent indium-tin-oxide(ITO)electrode can be fully coated on the self-assembled SiNW arrays by sputtering.The ITO-coated SiNW solar cells show the same low surface light reflectance and a higher carrier collection efficiency than SiNW solar cells without ITO coating.An efficiency enhancement of around 3 times for ITO coated SiNW solar cells is demonstrated via experiments.
基金Supported by Ministry of Education Doctoral Foundation (20070460001)Natural Science Foundation of Henan Province (0623021400)
文摘Based on simulated material scale modeling and numerical simulation, the protective seam mining method was conducted at one coal mine. After extracting the No.15seam, the overlying strata movement and the deformation of the No.9-10 protected seamwere studied. The experiment results show that it is feasible to destress the protectedseams with large interburden thickness. When the face had advanced 200 m from thesetup room, the No.9-10 seam was fully destressed, resulting in easy gas drainage in thedestressed zone. Recommendations on mining sequence of multiple seams mining in thesame coal areas were made.
