During advanced water detection using the transient electromagnetic method, the exploration effect for water-rich area is often poor due to the interference of bolts that are distributed in different positions in work...During advanced water detection using the transient electromagnetic method, the exploration effect for water-rich area is often poor due to the interference of bolts that are distributed in different positions in working face. Thus, the study on the interference characteristics of bolts in different states has important directive significance for improving the acquisition quality and data processing method in water detection. Based on the analysis of the distribution laws of magnetic field excited by small multi-turn coincident loop in full space of homogeneity, the test on the interference of bolts has been designed in the mine. Through drilling 18 holes around the overlapping coil in the working face, mass data are collected in order with the posi- tion change and the exposed bolt length. The results of comprehensive data analysis show that the transient electromagnetic field is strongly interfered as the distance between the bolt and the center of the coil is less than 3 m, and the interference varies greatly as the distance varies. On the other hand, the field induced by the bolts can be ignored as the distance exceeds 3 m. The findings can help to improve data acquisition and correction during advanced water detection when using the transient electromagnetic method.展开更多
Self-drilling screw bolts are a new product to replace ordinary screw bolts, and thus raise working efficiency ten times and reduce the cost of installation. According to the design theory of integrating drilling bit ...Self-drilling screw bolts are a new product to replace ordinary screw bolts, and thus raise working efficiency ten times and reduce the cost of installation. According to the design theory of integrating drilling bit with driving screw, the self-drilling screw bolt can complete successively the functions of drilling, screwing and fastening within several seconds, with the aid of a simple jig alone. This serves the development of board installations in room decoration and vehicle and ship building.展开更多
基金Supported by the Key Projects of Anhui Provincial Scientific and Technological Program （11010401015） the Key Program of National Natural Science Foundation of China （51134012）
文摘During advanced water detection using the transient electromagnetic method, the exploration effect for water-rich area is often poor due to the interference of bolts that are distributed in different positions in working face. Thus, the study on the interference characteristics of bolts in different states has important directive significance for improving the acquisition quality and data processing method in water detection. Based on the analysis of the distribution laws of magnetic field excited by small multi-turn coincident loop in full space of homogeneity, the test on the interference of bolts has been designed in the mine. Through drilling 18 holes around the overlapping coil in the working face, mass data are collected in order with the posi- tion change and the exposed bolt length. The results of comprehensive data analysis show that the transient electromagnetic field is strongly interfered as the distance between the bolt and the center of the coil is less than 3 m, and the interference varies greatly as the distance varies. On the other hand, the field induced by the bolts can be ignored as the distance exceeds 3 m. The findings can help to improve data acquisition and correction during advanced water detection when using the transient electromagnetic method.
文摘Self-drilling screw bolts are a new product to replace ordinary screw bolts, and thus raise working efficiency ten times and reduce the cost of installation. According to the design theory of integrating drilling bit with driving screw, the self-drilling screw bolt can complete successively the functions of drilling, screwing and fastening within several seconds, with the aid of a simple jig alone. This serves the development of board installations in room decoration and vehicle and ship building.
