With deep mining of coal mines, prospecting multilayer water-filled goaf has become a new content that results from geophysical exploration in coalfields. The central loop transient electromagnetic （TEM） method is f...With deep mining of coal mines, prospecting multilayer water-filled goaf has become a new content that results from geophysical exploration in coalfields. The central loop transient electromagnetic （TEM） method is favorable for prospecting conductive layers because of the coupling relationship between its field structure and formation. However, the shielding effect of conductive overburden would not only require a longer observation time when prospecting the same depth but also weaken the anomalous response of underlying layers. Through direct time domain numerical simulation and horizontal layered earth forward modeling, this paper estimates the length of observation time required to prospect the target, and the distinguishable criterion of multilayer water-filled goal is presented with observation error according to the effect of noise on observation data. The observed emf curves from Dazigou Coal Mine, Shanxi Province can distinguish multilayer water-filled goaf. In quantitative inversion interpretation of observed curves, using electric logging data as initial parameters restrains the equivalence caused by coal formation thin layers. The deduced three-layer and two-layer water-filled goals are confirmed by the drilling hole. The result suggests that when observation time is long enough and with the anomalous situation of underlying layers being greater than the observation error, the use of the central loop TEM method to orosoect a multilaver water-filled goaf is feasible.展开更多
At first, this paper presents the origin, developments and main view of Error Analysis. Then, based on the theories of Error Analysis, this paper collected and analyzed 398 errors in 30 compositions randomly selected ...At first, this paper presents the origin, developments and main view of Error Analysis. Then, based on the theories of Error Analysis, this paper collected and analyzed 398 errors in 30 compositions randomly selected from CLEC, written for the exam of CET-4. The results showed that errors were mainly expressed form the aspects of usage of words and forms, and rooted from three sources, the shortage on knowledge of grammar and the lack of standardization on language usage, intralingual transfer and the interlingual transfer. Then, this paper touched upon the principles and methods of English writing to provide with some suggestions for the teaching of English writing in China.展开更多
基金supported by the National Science Foundation of China(No.41374129)Science and Technology Project of Shanxi Province(No.20100321066)Research and Development Project of National Major Scientifi c Research Equipment(No.ZDYZ2012-1-05-04)
文摘With deep mining of coal mines, prospecting multilayer water-filled goaf has become a new content that results from geophysical exploration in coalfields. The central loop transient electromagnetic （TEM） method is favorable for prospecting conductive layers because of the coupling relationship between its field structure and formation. However, the shielding effect of conductive overburden would not only require a longer observation time when prospecting the same depth but also weaken the anomalous response of underlying layers. Through direct time domain numerical simulation and horizontal layered earth forward modeling, this paper estimates the length of observation time required to prospect the target, and the distinguishable criterion of multilayer water-filled goal is presented with observation error according to the effect of noise on observation data. The observed emf curves from Dazigou Coal Mine, Shanxi Province can distinguish multilayer water-filled goaf. In quantitative inversion interpretation of observed curves, using electric logging data as initial parameters restrains the equivalence caused by coal formation thin layers. The deduced three-layer and two-layer water-filled goals are confirmed by the drilling hole. The result suggests that when observation time is long enough and with the anomalous situation of underlying layers being greater than the observation error, the use of the central loop TEM method to orosoect a multilaver water-filled goaf is feasible.
文摘At first, this paper presents the origin, developments and main view of Error Analysis. Then, based on the theories of Error Analysis, this paper collected and analyzed 398 errors in 30 compositions randomly selected from CLEC, written for the exam of CET-4. The results showed that errors were mainly expressed form the aspects of usage of words and forms, and rooted from three sources, the shortage on knowledge of grammar and the lack of standardization on language usage, intralingual transfer and the interlingual transfer. Then, this paper touched upon the principles and methods of English writing to provide with some suggestions for the teaching of English writing in China.
