In the context of additive manufacturing processes,the influence of specimen deformation from different welding paths is conducted by using CMT-AM.A least-squares method was used to quantitatively measure specimen def...In the context of additive manufacturing processes,the influence of specimen deformation from different welding paths is conducted by using CMT-AM.A least-squares method was used to quantitatively measure specimen deformation.The values of S(i.e.,the sum of the distance from each feature point in a plane to the ideal plane)from different welding paths had significant influence on deformation of deposited layer.With the value of S increasing,the deformation of deposited layer gradually increased.With this result,a suitable welding trace plan was ascertained,which was successfully used to acquire well-formed and densely organized specimens during the arc-welding additive manufacturing process.Our results provide a foundation for experiments based on deposited layer scanning trace planning.展开更多
Tomographic gamma scanner(TGS),an advancedγ-ray nondestructive analysis technique,can locate and analyze nuclides in radioactive nuclear waste,and TGS can be categorized into two processes:e.g.,transmission measureme...Tomographic gamma scanner(TGS),an advancedγ-ray nondestructive analysis technique,can locate and analyze nuclides in radioactive nuclear waste,and TGS can be categorized into two processes:e.g.,transmission measurement and emission measurement.Specifically,transmission measurements provide the basis for accurate measurement of nonuniform radionuclide content in TGS scanning.The scan data were obtained using the Monte Carlo tool Geant4 simulation,and 25 voxels were divided into five lengths and five widths in a square barrel.In this study,an encoding cropping algorithm based on draped foot vector judgment was adopted to rapidly calculate the voxel trace matrix within a square bucket of nuclear waste,and the transmission images were reconstructed using ordered subset expectation maximization.The results indicated that the cropping speed of the improved coding algorithm was significantly higher than that of the original algorithm,and the relative mean deviation and root-mean-square error between the reconstructed attenuation coefficient and the reference standard value tended to decrease with an increase in the cropped line segments in the voxel;the Pearson correlation coefficient tended to converge to 1.0.The image quality evaluation parameters of the high media-density materials were better than those of the low media-density materials in the above three indexes.The reconstruction effect was relatively poor for more complex filling materials.When there were more than 10 cropped line segments in the voxel,the reconstruction data generally tended to be stable.The graphical trimming algorithm can rapidly calculate the trace matrix of the scanned voxels;it exhibits the advantages of speed and efficiency and can serve as a novel method to solve the trace matrix of TGS nuclear waste transmission scans.展开更多
Studies on distribution of trace gold mostly focus on some samples in whichgold content is well above 100 ppm at the present time due to the limitation of analy-sis methods. Progress in research on trace gold (usually...Studies on distribution of trace gold mostly focus on some samples in whichgold content is well above 100 ppm at the present time due to the limitation of analy-sis methods. Progress in research on trace gold (usually less than 100 ppm to n ppm)was rarely reported. Although electronic microprobe (EMP) and scanning electronicmicroprobe (SEM) have a high resolution, their detection limits are still 100-500ppm and 100-300 ppm, respectively. And also the electronic paramagnetic reso-nance spectrometer, an effective method for determining lattice gold of a few tenppm level, unfortunately is still incapable of doing such research. Newly展开更多
基金Project was supported by the National Natural Science Foundation of China(51475104,51435004)National Key Basic Research and Development Planning Project(973 plan)(No.2013CB035500).
文摘In the context of additive manufacturing processes,the influence of specimen deformation from different welding paths is conducted by using CMT-AM.A least-squares method was used to quantitatively measure specimen deformation.The values of S(i.e.,the sum of the distance from each feature point in a plane to the ideal plane)from different welding paths had significant influence on deformation of deposited layer.With the value of S increasing,the deformation of deposited layer gradually increased.With this result,a suitable welding trace plan was ascertained,which was successfully used to acquire well-formed and densely organized specimens during the arc-welding additive manufacturing process.Our results provide a foundation for experiments based on deposited layer scanning trace planning.
基金supported by the National Natural Science Foundation of China(No.U19A2086)the fund of Science and Technology Bureau of LeShan City(No.22ZDYJ0015).
文摘Tomographic gamma scanner(TGS),an advancedγ-ray nondestructive analysis technique,can locate and analyze nuclides in radioactive nuclear waste,and TGS can be categorized into two processes:e.g.,transmission measurement and emission measurement.Specifically,transmission measurements provide the basis for accurate measurement of nonuniform radionuclide content in TGS scanning.The scan data were obtained using the Monte Carlo tool Geant4 simulation,and 25 voxels were divided into five lengths and five widths in a square barrel.In this study,an encoding cropping algorithm based on draped foot vector judgment was adopted to rapidly calculate the voxel trace matrix within a square bucket of nuclear waste,and the transmission images were reconstructed using ordered subset expectation maximization.The results indicated that the cropping speed of the improved coding algorithm was significantly higher than that of the original algorithm,and the relative mean deviation and root-mean-square error between the reconstructed attenuation coefficient and the reference standard value tended to decrease with an increase in the cropped line segments in the voxel;the Pearson correlation coefficient tended to converge to 1.0.The image quality evaluation parameters of the high media-density materials were better than those of the low media-density materials in the above three indexes.The reconstruction effect was relatively poor for more complex filling materials.When there were more than 10 cropped line segments in the voxel,the reconstruction data generally tended to be stable.The graphical trimming algorithm can rapidly calculate the trace matrix of the scanned voxels;it exhibits the advantages of speed and efficiency and can serve as a novel method to solve the trace matrix of TGS nuclear waste transmission scans.
文摘Studies on distribution of trace gold mostly focus on some samples in whichgold content is well above 100 ppm at the present time due to the limitation of analy-sis methods. Progress in research on trace gold (usually less than 100 ppm to n ppm)was rarely reported. Although electronic microprobe (EMP) and scanning electronicmicroprobe (SEM) have a high resolution, their detection limits are still 100-500ppm and 100-300 ppm, respectively. And also the electronic paramagnetic reso-nance spectrometer, an effective method for determining lattice gold of a few tenppm level, unfortunately is still incapable of doing such research. Newly
