To investigate decay law of acoustic emission and microseismic activities caused by disturbances associated with multilevel loading and mining blast,a new exponential decay(ED)law was proposed.The results show that th...To investigate decay law of acoustic emission and microseismic activities caused by disturbances associated with multilevel loading and mining blast,a new exponential decay(ED)law was proposed.The results show that the micro-fracture activity decay law after multistage stress loading and blasting disturbance conforms to the ED model,in which the sum of A and n represents the number of initial micro-fracture events,and n represents the level of background micro-fracture events.The ED model can describe the number of initial micro-fracture events with a deviation less than 10%.The ED model outperforms the traditional aftershock models in describing the micro-fracture event decay law in the three cases considered.The ED model can provide a reference for selecting the blasting interval in mines,which is of great significance to maintain the stability of the surrounding rock and ensure safe production in metal mines.展开更多
It is of great importance to determine an unknown quantum state for fundamental studies of quantum mechanics,yet it is still difficult to characterize systems of large dimensions in practice.Although the scan-free dir...It is of great importance to determine an unknown quantum state for fundamental studies of quantum mechanics,yet it is still difficult to characterize systems of large dimensions in practice.Although the scan-free direct measurement approach based on a weak measurement scheme was proposed to measure a high-dimensional photonic state,how weak the interaction should be to give a correct estimation remains unclear.Here we propose and experimentally demonstrate a technique that measures a high-dimensional quantum state with the combination of scan-free measurement and direct strong measurement.The procedure involves sequential strong measurement,in which case no approximation is made similarly to the conventional direct weak measurement.We use this method to measure a transverse state of a photon with effective dimensionality of 65000 without the time-consumed scanning process.Furthermore,the high fidelity of the result and the simplicity of the experimental apparatus show that our approach can be readily used to measure the complex field of a beam in diverse applications such as wavefront sensing and quantitative phase imaging.展开更多
基金financial supports from the National Natural Science Foundation of China(Nos.51704056,51974059)the China Postdoctoral Science Foundation(No.2017M621152)the Fundamental Research Funds for the Central University of China(Nos.N160103006,N180115010,N2001001)。
文摘To investigate decay law of acoustic emission and microseismic activities caused by disturbances associated with multilevel loading and mining blast,a new exponential decay(ED)law was proposed.The results show that the micro-fracture activity decay law after multistage stress loading and blasting disturbance conforms to the ED model,in which the sum of A and n represents the number of initial micro-fracture events,and n represents the level of background micro-fracture events.The ED model can describe the number of initial micro-fracture events with a deviation less than 10%.The ED model outperforms the traditional aftershock models in describing the micro-fracture event decay law in the three cases considered.The ED model can provide a reference for selecting the blasting interval in mines,which is of great significance to maintain the stability of the surrounding rock and ensure safe production in metal mines.
基金Supported by the National Natural Science Foundation of China(Grant Nos.11574291,11774334,11774335,11674306 and 61590932)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB01030200)+2 种基金the National Key Research and Development Program of China(Grant Nos.2016YFA0301300,2016YFA0301700 and 2017YFA0304100)the Key Research Program of Frontier Science,CAS(Grant No.QYZDY-SSW-SLH003)Anhui Initiative in Quantum Information Technologies.
文摘It is of great importance to determine an unknown quantum state for fundamental studies of quantum mechanics,yet it is still difficult to characterize systems of large dimensions in practice.Although the scan-free direct measurement approach based on a weak measurement scheme was proposed to measure a high-dimensional photonic state,how weak the interaction should be to give a correct estimation remains unclear.Here we propose and experimentally demonstrate a technique that measures a high-dimensional quantum state with the combination of scan-free measurement and direct strong measurement.The procedure involves sequential strong measurement,in which case no approximation is made similarly to the conventional direct weak measurement.We use this method to measure a transverse state of a photon with effective dimensionality of 65000 without the time-consumed scanning process.Furthermore,the high fidelity of the result and the simplicity of the experimental apparatus show that our approach can be readily used to measure the complex field of a beam in diverse applications such as wavefront sensing and quantitative phase imaging.
