Accurate extraction of pores and fractures is a prerequisite for constructing digital rocks for physical property simulation and microstructural response analysis.However,fractures in CT images are similar in grayscal...Accurate extraction of pores and fractures is a prerequisite for constructing digital rocks for physical property simulation and microstructural response analysis.However,fractures in CT images are similar in grayscale to the rock matrix,and traditional algorithms have difficulty to achieve accurate segmentation results.In this study,a dataset containing multiscale fracture information was constructed,and a U-Net semantic segmentation model with a scSE attention mechanism was used to classify shale CT images at the pixel level and compare the results with traditional methods.The results showed that the CLAHE algorithm effectively removed noise and enhanced the fracture information in the dark parts,which is beneficial for further fracture extraction.The Canny edge detection algorithm had significant false positives and failed to recognize the internal information of the fractures.The Otsu algorithm only extracted fractures with a significant difference from the background and was not sensitive enough for fine fractures.The MEF algorithm enhanced the edge information of the fractures and was also sensitive to fine fractures,but it overestimated the aperture of the fractures.The U-Net was able to identify almost all fractures with good continuity,with an MIou and Recall of 0.80 and 0.82,respectively.As the image resolution increases,more fine fracture information can be extracted.展开更多
Pt rare earth compounds have recently been investigated as potential substitutes.In this study,the hydrogen reduction method was used to prepare the Pt-Dy bimetallic catalyst,and a number of characterizations were con...Pt rare earth compounds have recently been investigated as potential substitutes.In this study,the hydrogen reduction method was used to prepare the Pt-Dy bimetallic catalyst,and a number of characterizations were conducted for structure and morphological research.The high resolutiontransmission electron microscopy(HR-TEM)and X-ray diffraction results show that Pt-Dy composite material exists in the form of various alloys and has a clear spherical shape.The majority of the metals in the composite catalyst appear in the zero valent state,and the binding energy of Pt shifts significantly,according to an X-ray photoelectron spectroscopy measurement.Impressively,Pt-Dy alloy produces excellent mass activity of 594 A/g compared to commercial Pt/C catalyst(162.8 A/g)for oxygen reduction process.Furthermore,after an accele rated durability test,the catalytic activity loss for Pt-Dy alloy catalyst reaches 20%while commercial Pt/C reduces 56%.展开更多
基金funded by the Natural Science Basis Research Plan in Shaanxi Province of China(No.2022JM-147).
文摘Accurate extraction of pores and fractures is a prerequisite for constructing digital rocks for physical property simulation and microstructural response analysis.However,fractures in CT images are similar in grayscale to the rock matrix,and traditional algorithms have difficulty to achieve accurate segmentation results.In this study,a dataset containing multiscale fracture information was constructed,and a U-Net semantic segmentation model with a scSE attention mechanism was used to classify shale CT images at the pixel level and compare the results with traditional methods.The results showed that the CLAHE algorithm effectively removed noise and enhanced the fracture information in the dark parts,which is beneficial for further fracture extraction.The Canny edge detection algorithm had significant false positives and failed to recognize the internal information of the fractures.The Otsu algorithm only extracted fractures with a significant difference from the background and was not sensitive enough for fine fractures.The MEF algorithm enhanced the edge information of the fractures and was also sensitive to fine fractures,but it overestimated the aperture of the fractures.The U-Net was able to identify almost all fractures with good continuity,with an MIou and Recall of 0.80 and 0.82,respectively.As the image resolution increases,more fine fracture information can be extracted.
基金supported by the National Natural Science Foundation of China(21975151)。
文摘Pt rare earth compounds have recently been investigated as potential substitutes.In this study,the hydrogen reduction method was used to prepare the Pt-Dy bimetallic catalyst,and a number of characterizations were conducted for structure and morphological research.The high resolutiontransmission electron microscopy(HR-TEM)and X-ray diffraction results show that Pt-Dy composite material exists in the form of various alloys and has a clear spherical shape.The majority of the metals in the composite catalyst appear in the zero valent state,and the binding energy of Pt shifts significantly,according to an X-ray photoelectron spectroscopy measurement.Impressively,Pt-Dy alloy produces excellent mass activity of 594 A/g compared to commercial Pt/C catalyst(162.8 A/g)for oxygen reduction process.Furthermore,after an accele rated durability test,the catalytic activity loss for Pt-Dy alloy catalyst reaches 20%while commercial Pt/C reduces 56%.
