The hidden water-bearing structures near the roadway tunnelling face are very likely to cause water seepage accidents in coal mines.Currently,transient electromagnetic(EM)technology has be-come an important method to ...The hidden water-bearing structures near the roadway tunnelling face are very likely to cause water seepage accidents in coal mines.Currently,transient electromagnetic(EM)technology has be-come an important method to detect water damage in advance of roadway excavation.In this paper,the time-domain finite element algorithm based on unstructured tetrahedron grids is used to accurate-ly simulate the geological body in front of the roadway excavation face and analyze its response.The authors detect the distance between the roadway excavation face and the low-resistivity water-bearing body,the resistivity difference between the low-resistivity body and surrounding rock,and the influence of the size of the low-resistivity body on the transient EM response.Furthermore,the common types of low-resistivity bodies in the roadway drivage process are used for modeling to analyze the attenuation of the detected EM response when there are low-resistivity bodies in front of the roadway.The research in this paper can help effectively detecting the water-bearing low-resistivity body in front of the roadway drivage and lay a foundation for reducing the risk of water seepage accidents.展开更多
Objective The MicroTCA.4(MTCA.4)standard systems have been widely used in large-scale scientific facilities such as synchrotron radiation light sources and FELs over the world,covering RF control,beam instrumentation,...Objective The MicroTCA.4(MTCA.4)standard systems have been widely used in large-scale scientific facilities such as synchrotron radiation light sources and FELs over the world,covering RF control,beam instrumentation,timing,machine protection,and so on.The MTCA.4 module management controller(MMC)realizes intelligent management of the boards in the chassis through bus protocol and system interaction.It is an important functional module in MTCA.4 standard system.Methods In order to meet the requirements of the large scientific facilities,an MMC module was designed and developed.This design can realize power management of Advanced Mezzanine Card(AMC)and Rear Transition Module(RTM)boards,as well as monitoring the temperature,voltage,and current during operation.The core part of this module is limited into an area of 3 cm 3 cm on the AMC board,leaving large space for subsequent development of functional circuit.Results An AMC board was developed to verify functions of the MMC.Test results indicate that this board is compatible with existing MTCA.4 standard system.Conclusions This MMC solution can be directly and modularly applied to the design of MTCA.4 standard hardware.展开更多
文摘The hidden water-bearing structures near the roadway tunnelling face are very likely to cause water seepage accidents in coal mines.Currently,transient electromagnetic(EM)technology has be-come an important method to detect water damage in advance of roadway excavation.In this paper,the time-domain finite element algorithm based on unstructured tetrahedron grids is used to accurate-ly simulate the geological body in front of the roadway excavation face and analyze its response.The authors detect the distance between the roadway excavation face and the low-resistivity water-bearing body,the resistivity difference between the low-resistivity body and surrounding rock,and the influence of the size of the low-resistivity body on the transient EM response.Furthermore,the common types of low-resistivity bodies in the roadway drivage process are used for modeling to analyze the attenuation of the detected EM response when there are low-resistivity bodies in front of the roadway.The research in this paper can help effectively detecting the water-bearing low-resistivity body in front of the roadway drivage and lay a foundation for reducing the risk of water seepage accidents.
基金funded by the National Natural Science Foundation of China(No.11675174,No.11805219).Author informa。
文摘Objective The MicroTCA.4(MTCA.4)standard systems have been widely used in large-scale scientific facilities such as synchrotron radiation light sources and FELs over the world,covering RF control,beam instrumentation,timing,machine protection,and so on.The MTCA.4 module management controller(MMC)realizes intelligent management of the boards in the chassis through bus protocol and system interaction.It is an important functional module in MTCA.4 standard system.Methods In order to meet the requirements of the large scientific facilities,an MMC module was designed and developed.This design can realize power management of Advanced Mezzanine Card(AMC)and Rear Transition Module(RTM)boards,as well as monitoring the temperature,voltage,and current during operation.The core part of this module is limited into an area of 3 cm 3 cm on the AMC board,leaving large space for subsequent development of functional circuit.Results An AMC board was developed to verify functions of the MMC.Test results indicate that this board is compatible with existing MTCA.4 standard system.Conclusions This MMC solution can be directly and modularly applied to the design of MTCA.4 standard hardware.
