This paper presents results of an experimental study to characterize the law of mineral change of fallen rock in coal mine groundwater reservoir ant its influence on water quality.The minerals of the underground reser...This paper presents results of an experimental study to characterize the law of mineral change of fallen rock in coal mine groundwater reservoir ant its influence on water quality.The minerals of the underground reservoir of Daliuta Coal Mine is taken as the research object.Simulation experiments were designed and conducted to simulate water–rock action in the laboratory.The mineral composition was analyzed by X-ray diffractometer(XRD),the surface morphology of the mineral was analyzed by scanning electron microscope(SEM),and the specific surface area,total pore volume and average pore diameter of the mineral were measured by fast specific surface/pore analyzer(BET).The experimental results show that the sandstone and mudstone in the groundwater reservoir of Daliuta Coal Mine account for 70%and 30%,respectively.The pore diameter is 15.62–17.55 nm,and pore volume is 0.035 cc/g.Its pore structure is a key factor in the occurrence of water–rock interaction.According to the water–rock simulation experiment,the quartz content before the water–rock action is about 34.28%,the albite is about 21.84%,the feldspar is about 17.48%,and the kaolinite is about 8.00%.After the water–rock action,they are 36.14%,17.78%,11.62%,and 16.75%,respectively.The content of albite and orthoclase is reduced while the content of kaolinite is increased,that is,the Na+content becomes higher,and the Ca2+and Mg2+contents become lower.This research builds a good theoretical foundation for revealing the role of water and rock in underground coal reservoirs.展开更多
Instance segmentation in aerial images is an important and challenging task.Most of the existing methods have adapted instance segmentation algorithms developed for natural images to aerial images.However,these method...Instance segmentation in aerial images is an important and challenging task.Most of the existing methods have adapted instance segmentation algorithms developed for natural images to aerial images.However,these methods easily suffer from performance degradation in aerial images,due to the scale variations,large aspect ratios,and arbitrary orientations of instances caused by the bird’s-eye view of aerial images.To address this issue,we propose an elliptic centerness(EC)for instance segmentation in aerial images,which can assign the proper centerness values to the intricate aerial instances and thus mitigate the performance degradation.Specifically,we introduce ellipses to fit the various contours of aerial instances and measure these fitted ellipses by two-dimensional anisotropic Gaussian distribution.Armed with EC,we develop a one-stage aerial instance segmentation network.Extensive experiments on a commonly used dataset,the instance segmentation in aerial images dataset(iSAID),demonstrate that our proposed method can achieve a remarkable performance of instance segmentation while introducing negligible computational cost.展开更多
基金This work was co-supported by the Yue Qi Young Scholar Project,China University of Mining&Technology,Beijing(2019QN08)National Key Research and Development Program of China(2018YFC0406404)+2 种基金Research on Ecological Restoration and Protection of Coal Base in Arid Eco-fragile Region(GJNY2030XDXM-19-03.2)the Fundamental Research Funds for the Central Universities(2020YJSHH12)the scientific and technological innovation project of Shenhua Group(SHJT-16-28).
文摘This paper presents results of an experimental study to characterize the law of mineral change of fallen rock in coal mine groundwater reservoir ant its influence on water quality.The minerals of the underground reservoir of Daliuta Coal Mine is taken as the research object.Simulation experiments were designed and conducted to simulate water–rock action in the laboratory.The mineral composition was analyzed by X-ray diffractometer(XRD),the surface morphology of the mineral was analyzed by scanning electron microscope(SEM),and the specific surface area,total pore volume and average pore diameter of the mineral were measured by fast specific surface/pore analyzer(BET).The experimental results show that the sandstone and mudstone in the groundwater reservoir of Daliuta Coal Mine account for 70%and 30%,respectively.The pore diameter is 15.62–17.55 nm,and pore volume is 0.035 cc/g.Its pore structure is a key factor in the occurrence of water–rock interaction.According to the water–rock simulation experiment,the quartz content before the water–rock action is about 34.28%,the albite is about 21.84%,the feldspar is about 17.48%,and the kaolinite is about 8.00%.After the water–rock action,they are 36.14%,17.78%,11.62%,and 16.75%,respectively.The content of albite and orthoclase is reduced while the content of kaolinite is increased,that is,the Na+content becomes higher,and the Ca2+and Mg2+contents become lower.This research builds a good theoretical foundation for revealing the role of water and rock in underground coal reservoirs.
基金This work was supported by the Fundamental Research Funds for the Central Universities(grant number:2042021kf0040).
文摘Instance segmentation in aerial images is an important and challenging task.Most of the existing methods have adapted instance segmentation algorithms developed for natural images to aerial images.However,these methods easily suffer from performance degradation in aerial images,due to the scale variations,large aspect ratios,and arbitrary orientations of instances caused by the bird’s-eye view of aerial images.To address this issue,we propose an elliptic centerness(EC)for instance segmentation in aerial images,which can assign the proper centerness values to the intricate aerial instances and thus mitigate the performance degradation.Specifically,we introduce ellipses to fit the various contours of aerial instances and measure these fitted ellipses by two-dimensional anisotropic Gaussian distribution.Armed with EC,we develop a one-stage aerial instance segmentation network.Extensive experiments on a commonly used dataset,the instance segmentation in aerial images dataset(iSAID),demonstrate that our proposed method can achieve a remarkable performance of instance segmentation while introducing negligible computational cost.
