To further identify the dynamics of the period-adding bifurcation scenarios observed in both biological experiment and simulations with differential Chay model, this paper fits a discontinuous map of a slow control va...To further identify the dynamics of the period-adding bifurcation scenarios observed in both biological experiment and simulations with differential Chay model, this paper fits a discontinuous map of a slow control variable of Chay model based on simulation results. The procedure of period adding bifurcation scenario from period k to period k ＋ 1 bursting （k = 1, 2, 3, 4） involved in the period-adding cascades and the stochastic effect of noise near each bifurcation point is also reproduced in the discontinuous map. Moreover, dynamics of the border-collision bifurcation is identified in the discontinuous map, which is employed to understand the experimentally observed period increment sequence. The simple discontinuous map is of practical importance in modeling of collective behaviours of neural populations like synchronization in large neural circuits.展开更多
Many monitoring measures were used in the production field for predicting rockburst.However, predicting rock burst according to complicated observation data is alwaysa pressing problem in this research field.Though th...Many monitoring measures were used in the production field for predicting rockburst.However, predicting rock burst according to complicated observation data is alwaysa pressing problem in this research field.Though the critical value method gets extensiveapplication in practice, it stresses only on the superficial change of data and overlooks alot of features of rock burst and useful information that is concealed and hidden in the observationtime series.Pattern recognition extracts the feature value of time domain, frequencydomain and wavelet domain in observation time series to form Multi-Feature vectors,using Euclidean distance measure as the separable criterion between the same typeand different type to compress and transform feature vectors.It applies neural network asa tool to recognize the danger of rock burst, and uses feature vectors being compressedto carry out training and studying.It is proved by test samples that predicting precisionshould be prior to such traditional predicting methods as pattern recognition and critical indicatormethod.展开更多
The mechanisms for rock bursts occurrences in fold zones are complex, and the redistribution of in-situ stresses is closely related to the complexity of the structures. Analysis of the geomorphology of fold structures...The mechanisms for rock bursts occurrences in fold zones are complex, and the redistribution of in-situ stresses is closely related to the complexity of the structures. Analysis of the geomorphology of fold structures and changes of coal thickness can help identify zones prone to rock bursts to improve safety and productivity in coal mines. This study investigated the distribution characteristics of fold structures in coal seams in fold zones in four mines in northwest China. Geometrical characteristics of fold structures in coal seams and changes of coal thickness were analysed, based on comprehensive evaluation indexes,such as the length–width ratio of folds, interlimb angle, ratio P1 of projected width of fold limbs to that of the hinge zone, curvature ratio P2, the maximum curvature and amplitude. The statistical analysis of the four coal mines shows that the length–width ratio of folds changed from 0.78 to 2.03 and the maximum curvature of cross sections of folds was less than 0.04. The curvature ratio of cross section of a fold in the structure was no more than 1.4 and the interlimb angles of cross sections of 89% of folds were larger than 150°. Gentle fold structures were dominant and the specific geological morphologies were domes or basins. The isopleth of coal thickness above the coal mines showed a fluctuation trend similar to the contour line of the floor of coal seams. The coal thickness in an anticline area was smaller than that in the neighboring syncline area. Therefore, the overall variation of coal thickness in the mining areas was likely to have a relation with the direction of the regional principal stress.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10774088,10772101,30770701 and 10875076)the Fundamental Research Funds for the Central Universities(Grant No.GK200902025)
文摘To further identify the dynamics of the period-adding bifurcation scenarios observed in both biological experiment and simulations with differential Chay model, this paper fits a discontinuous map of a slow control variable of Chay model based on simulation results. The procedure of period adding bifurcation scenario from period k to period k ＋ 1 bursting （k = 1, 2, 3, 4） involved in the period-adding cascades and the stochastic effect of noise near each bifurcation point is also reproduced in the discontinuous map. Moreover, dynamics of the border-collision bifurcation is identified in the discontinuous map, which is employed to understand the experimentally observed period increment sequence. The simple discontinuous map is of practical importance in modeling of collective behaviours of neural populations like synchronization in large neural circuits.
文摘Many monitoring measures were used in the production field for predicting rockburst.However, predicting rock burst according to complicated observation data is alwaysa pressing problem in this research field.Though the critical value method gets extensiveapplication in practice, it stresses only on the superficial change of data and overlooks alot of features of rock burst and useful information that is concealed and hidden in the observationtime series.Pattern recognition extracts the feature value of time domain, frequencydomain and wavelet domain in observation time series to form Multi-Feature vectors,using Euclidean distance measure as the separable criterion between the same typeand different type to compress and transform feature vectors.It applies neural network asa tool to recognize the danger of rock burst, and uses feature vectors being compressedto carry out training and studying.It is proved by test samples that predicting precisionshould be prior to such traditional predicting methods as pattern recognition and critical indicatormethod.
基金the financial support provided by the State Key Research Development Program of China (No.2016YFC0801406)the Natural Science Foundation of Jiangsu Province of China (No.BK20171191)National Natural Science Foundation of China(Nos.51674253,51734009)
文摘The mechanisms for rock bursts occurrences in fold zones are complex, and the redistribution of in-situ stresses is closely related to the complexity of the structures. Analysis of the geomorphology of fold structures and changes of coal thickness can help identify zones prone to rock bursts to improve safety and productivity in coal mines. This study investigated the distribution characteristics of fold structures in coal seams in fold zones in four mines in northwest China. Geometrical characteristics of fold structures in coal seams and changes of coal thickness were analysed, based on comprehensive evaluation indexes,such as the length–width ratio of folds, interlimb angle, ratio P1 of projected width of fold limbs to that of the hinge zone, curvature ratio P2, the maximum curvature and amplitude. The statistical analysis of the four coal mines shows that the length–width ratio of folds changed from 0.78 to 2.03 and the maximum curvature of cross sections of folds was less than 0.04. The curvature ratio of cross section of a fold in the structure was no more than 1.4 and the interlimb angles of cross sections of 89% of folds were larger than 150°. Gentle fold structures were dominant and the specific geological morphologies were domes or basins. The isopleth of coal thickness above the coal mines showed a fluctuation trend similar to the contour line of the floor of coal seams. The coal thickness in an anticline area was smaller than that in the neighboring syncline area. Therefore, the overall variation of coal thickness in the mining areas was likely to have a relation with the direction of the regional principal stress.
基金This work was supported by the National Natural Science Foundation of China (No. 30030040) and the National Basic Research Programme of China (No. G1999054000)
