[目的/意义]苹果“冰糖心”又称水心病,是一种常见的果实病害,严重的水心病果会随着储藏时间的增加发生霉变,造成食品安全隐患。为实现不同等级水心病苹果快速无损检测,本研究旨在构建有效的分级与可溶性固形物(Soluble Solids Content,...[目的/意义]苹果“冰糖心”又称水心病,是一种常见的果实病害,严重的水心病果会随着储藏时间的增加发生霉变,造成食品安全隐患。为实现不同等级水心病苹果快速无损检测,本研究旨在构建有效的分级与可溶性固形物(Soluble Solids Content,SSC)预测模型。[方法]本研究选取了230个富士苹果,其中正常、轻度、中度、重度水心苹果数量分别为113、61、47和9个,分别采集了400~1000 nm范围的反射光谱和X射线计算机断层成像(X-ray Computed Tomography,X-ray CT)数据,并测定了SSC含量。[结果和讨论]SSC随水心程度加剧呈上升趋势,重度水心苹果呈现更高的光谱反射率,X-ray CT扫描成像观察到水心区域的组织体积平均密度高于健康组织,基于三维重建算法实现不同等级水心苹果内部水心组织可视化分布。基于偏最小二乘判别分析(Partial Least Squares Discriminant Analysis,PLSDA)构建的不同水心程度苹果果实分级模型建模集和测试集准确率分别为98.7%和95.9%;构建不同水心程度苹果果实SSC回归模型,校正集决定系数(Correlation Coefficient of Calibration,R_(C)^(2))为0.962,均方根误差(Root Mean Squares Error of Calibration,RMSEC)为0.264,测试集决定系数(Correlation Coefficient of Prediction,R_(P)^(2))为0.879,均方根误差(Root Mean Squares Error of Prediction,RMSEP)为0.435。[结论]该研究构建的不同水心程度苹果果实分级模型能够实现苹果不同等级水心病的预测,构建的不同水心程度苹果果实SSC回归模型能够较好地预测苹果果实的SSC,为苹果水心病无损检测和品质评估提供了有效方法。展开更多
Dose estimation and quality control in computed tomography (CT) scanners are useful in controlling the dose of radiation given to patients while tests are carried out. The study was performed in a 16-slice Computed To...Dose estimation and quality control in computed tomography (CT) scanners are useful in controlling the dose of radiation given to patients while tests are carried out. The study was performed in a 16-slice Computed Tomography (CT) system of LightSpeed RT16 Xtra CT scanner. Quality control was done using a vendor-provided QA Phantom, and the six aspects of image quality were measured. For CT dosimetry, Computed Tomography Dose index volume (CTDIvol) was performed using Computed Tomography Dose Index (CTDI) Phantom. CTDI Phantom consists of three parts: Pediatric Head, Adult Head, and Adult Body Phantom. A 10 cm long pencil ion chamber DCT-10 was used to measure the dose at different positions inside the CTDI Phantom. Data were collected using MagicMax Universal software. For dose estimation of the CTDIvol Report of AAPM Task Group, 96 and 111 formalisms were used. For Pediatric Head, Adult Head, and Adult Body Phantom the measured CIDIvol was 61.04 mGy, 48.11 mGy, and 18.08 mGy respectively. The study has shown deviations of 7%, 15%, and 19% between estimated and console-displayed doses for Pediatric Head, Adult Head, and Adult Body scan techniques respectively. The six aspects of image quality measured by QA Phantom were found to be compatible with the specifications of the machine and CTDIvol measured by CTDI Phantom were found within a tolerance limit of ±20%. Hence, the QC and dosimetry of the mentioned machine are within the limit.展开更多
Methane in-situ explosive fracturing technology produces shale debris particles within fracture channels,enabling a self-propping effect that enhances the fracture network conductivity and long-term stability.This stu...Methane in-situ explosive fracturing technology produces shale debris particles within fracture channels,enabling a self-propping effect that enhances the fracture network conductivity and long-term stability.This study employs X-ray computed tomography(CT)and digital volume correlation(DVC)to investigate the microstructural evolution and hydromechanical responses of shale self-propped fracture under varying confining pressures,highlighting the critical role of shale particles in maintaining fracture conductivity.Results indicate that the fracture aperture in the self-propped sample is significantly larger than in the unpropped sample throughout the loading process,with shale particles tending to crush rather than embedded into the matrix,thus maintaining flow pathways.As confining pressure increases,contact areas between fracture surfaces and particles expand,enhancing the system's stability and compressive resistance.Geometric analyses show flow paths becoming increasingly concentrated and branched under high stress.This resulted in a significant reduction in connectivity,restricting fracture permeability and amplifying the nonlinear gas flow behavior.This study introduces a permeability-strain recovery zone and a novel sensitivity parameter m,delineating stress sensitivity boundaries for permeability and normal strain,with m-value increasing with stress,revealing four characteristic regions.These findings offer theoretical support for optimizing fracturing techniques to enhance resource extraction efficiency.展开更多
To obtain two kinds of tomograms at two different X-ray energy ranges simultaneously, we have constructed a dual-energy X-ray photon counter with a lutetium-oxyorthosilicate photomultiplier detector system, three comp...To obtain two kinds of tomograms at two different X-ray energy ranges simultaneously, we have constructed a dual-energy X-ray photon counter with a lutetium-oxyorthosilicate photomultiplier detector system, three comparators, two microcomputers, and two frequency-voltage converters. X-ray photons are detected using the detector system, and the event pulses are input to three comparators simultaneously to determine threshold energies. At a tube voltage of 100 kV, the three threshold energies are 16, 35 and 52 keV, and two energy ranges are 16 - 35 and 52 - 100 keV. X-ray photons in the two ranges are counted using microcomputers, and the logical pulses from the two microcomputers are input to two frequency-voltage converters. In dual-energy computed tomography (CT), the tube voltage and current were 100 kV and 0.29 mA, respectively. Two tomograms were obtained simultaneously at two energy ranges. The energy ranges for gadolinium-L-edge and K-edge CT were 16 - 35 and 52 - 100 keV, respectively. The maximum count rate of dual-energy CT was 105 kilocounts per second with energies ranging from 16 to 100 keV, and the exposure time for tomography was 19.6 min.展开更多
To improve spectral X-ray CT reconstructed image quality, the energy-weighted reconstructed image xbins^W and the separable paraboloidal surrogates（SPS） algorithm are proposed for the prior image constrained compres...To improve spectral X-ray CT reconstructed image quality, the energy-weighted reconstructed image xbins^W and the separable paraboloidal surrogates（SPS） algorithm are proposed for the prior image constrained compressed sensing（PICCS）-based spectral X-ray CT image reconstruction. The PICCS-based image reconstruction takes advantage of the compressed sensing theory, a prior image and an optimization algorithm to improve the image quality of CT reconstructions.To evaluate the performance of the proposed method, three optimization algorithms and three prior images are employed and compared in terms of reconstruction accuracy and noise characteristics of the reconstructed images in each energy bin.The experimental simulation results show that the image xbins^W is the best as the prior image in general with respect to the three optimization algorithms; and the SPS algorithm offers the best performance for the simulated phantom with respect to the three prior images. Compared with filtered back-projection（FBP）, the PICCS via the SPS algorithm and xbins^W as the prior image can offer the noise reduction in the reconstructed images up to 80. 46%, 82. 51%, 88. 08% in each energy bin,respectively. M eanwhile, the root-mean-squared error in each energy bin is decreased by 15. 02%, 18. 15%, 34. 11% and the correlation coefficient is increased by 9. 98%, 11. 38%,15. 94%, respectively.展开更多
Distributed X-ray sources comprise a single vacuum chamber containing multiple X-ray sources that are triggered and emit X-rays at a specific time and location. This process facilitates an application for innovative s...Distributed X-ray sources comprise a single vacuum chamber containing multiple X-ray sources that are triggered and emit X-rays at a specific time and location. This process facilitates an application for innovative system concepts in X-ray and computer tomography. This paper proposes a novel electron beam focusing, shaping,and deflection electron gun for distributed X-ray sources.The electron gun uses a dispenser cathode as an electron emitter, a mesh grid to control emission current, and two electrostatic lenses for beam shaping, focusing, and deflection. Novel focusing and deflecting electrodes were designed to increase the number of focal spots in the distributed source. Two identical half-rectangle opening electrodes are controlled by adjusting the potential of the two electrodes to control the electron beam trajectory, and then, multifocal spots are obtained on the anode target. The electron gun can increase the spatial density of the distributed X-ray sources, thereby improving the image quality. The beam experimental results show that the focal spot sizes of the deflected(deflected amplitude 10.5 mm)and non-deflected electron beams at full width at half maximum are 0.80 mm 90.50 mm and 0.55 mm 90.40 mm, respectively(anode voltage 160 kV; beam current 30 mA). The imaging experimental results demonstrate the excellent spatial resolution and time resolution of an imaging system built with the sources, which has an excellent imaging effect on a field-programmable gate array chip and a rotating metal disk.展开更多
Due to heterogeneous pore distributions within shales,petrophysical properties of shales determined by scanning electron microscopy(SEM) and X-ray computed tomography(CT) methods strongly depend on the observed domain...Due to heterogeneous pore distributions within shales,petrophysical properties of shales determined by scanning electron microscopy(SEM) and X-ray computed tomography(CT) methods strongly depend on the observed domain size(analysis scale). In this paper,the influence of the analysis scale on areal and bulk porosities and pore size distribution(PSD) for lacustrine shales from the Dongying sag of Bohai Bay Basin,China were investigated using broad ion beam(BIB)-SEM and X-ray CT methods.The BIB-SEM cross-sections with high imaging resolution(10 nm/pixel) and a large field of view(>1 mm2)mainly describe the 2 D nanoscale pore system in the two shales(samples F41#-2 and Y556#-1),while CTbased 3 D reconstructions with resolutions of 0.42(F41#-1) and 0.5 μm/pixel(H172#-1) reflect the 3 D submicron pore system. The results indicate that the areal(bulk) porosity exhibits a multiple power-law distribution with increasing analysis area(volume),which can be used to extrapolate the porosity of a given area(volume). Based on SEM and CT investigations,the sizes of the minimum representative elementary areas(REAs) and volumes(REVs) were determined respectively,which are closely associated with the heterogeneousness of the pore system. Minimum REAs are proposed to be 2.93×10~4(F41#-2) and 0.91×10~4μm2(Y556#-1),and minimum REVs are 0.016(F41#-1) and 0.027 mm^3(H172#-1). As the analyzed areas(volumes) are larger than the minimum REA(REV),obtained 2 D(3 D) PSDs are comparable to each other and can be considered to reflect the shale PSD. These results provide insights into the porosity and PSD characterization of shales by SEM and X-ray CT methods.展开更多
Large areas of muddy sediments on the coastal shelves of China provide important samples for studying climate and ecological changes. Analysis of a large number of such samples, which is essential for systematic study...Large areas of muddy sediments on the coastal shelves of China provide important samples for studying climate and ecological changes. Analysis of a large number of such samples, which is essential for systematic study on environmental information recorded in mud areas because of complicated sedimentary environment and variable sedimentary rate, requires a fast and economical method. In this study, we investigated the potential of X-ray fluorescence core scanner （XRFS）, a fast analytical instrument for measuring the elemental concentrations of muddy sediments, and observed a significant correlation between the element concentrations of muddy sediments determined by regular X-ray fluorescence spectrometer （XRF） and XRFS, respectively. The correlations are mainly determined by excitation energy of elements, but also influenced by solubility of element ions. Furthermore, we found a striking link between A1 concentrations and marine-originated organic carbon （MOC）, a proxy of marine primary productivity. This indicates that MOC is partly controlled by sedimentary characteristics. Therefore, XRFS method has a good potential in fast analysis of a large number of muddy sediment samples, and it can also be used to calibrate MOC in ecological study of coastal seas.展开更多
文摘[目的/意义]苹果“冰糖心”又称水心病,是一种常见的果实病害,严重的水心病果会随着储藏时间的增加发生霉变,造成食品安全隐患。为实现不同等级水心病苹果快速无损检测,本研究旨在构建有效的分级与可溶性固形物(Soluble Solids Content,SSC)预测模型。[方法]本研究选取了230个富士苹果,其中正常、轻度、中度、重度水心苹果数量分别为113、61、47和9个,分别采集了400~1000 nm范围的反射光谱和X射线计算机断层成像(X-ray Computed Tomography,X-ray CT)数据,并测定了SSC含量。[结果和讨论]SSC随水心程度加剧呈上升趋势,重度水心苹果呈现更高的光谱反射率,X-ray CT扫描成像观察到水心区域的组织体积平均密度高于健康组织,基于三维重建算法实现不同等级水心苹果内部水心组织可视化分布。基于偏最小二乘判别分析(Partial Least Squares Discriminant Analysis,PLSDA)构建的不同水心程度苹果果实分级模型建模集和测试集准确率分别为98.7%和95.9%;构建不同水心程度苹果果实SSC回归模型,校正集决定系数(Correlation Coefficient of Calibration,R_(C)^(2))为0.962,均方根误差(Root Mean Squares Error of Calibration,RMSEC)为0.264,测试集决定系数(Correlation Coefficient of Prediction,R_(P)^(2))为0.879,均方根误差(Root Mean Squares Error of Prediction,RMSEP)为0.435。[结论]该研究构建的不同水心程度苹果果实分级模型能够实现苹果不同等级水心病的预测,构建的不同水心程度苹果果实SSC回归模型能够较好地预测苹果果实的SSC,为苹果水心病无损检测和品质评估提供了有效方法。
文摘Dose estimation and quality control in computed tomography (CT) scanners are useful in controlling the dose of radiation given to patients while tests are carried out. The study was performed in a 16-slice Computed Tomography (CT) system of LightSpeed RT16 Xtra CT scanner. Quality control was done using a vendor-provided QA Phantom, and the six aspects of image quality were measured. For CT dosimetry, Computed Tomography Dose index volume (CTDIvol) was performed using Computed Tomography Dose Index (CTDI) Phantom. CTDI Phantom consists of three parts: Pediatric Head, Adult Head, and Adult Body Phantom. A 10 cm long pencil ion chamber DCT-10 was used to measure the dose at different positions inside the CTDI Phantom. Data were collected using MagicMax Universal software. For dose estimation of the CTDIvol Report of AAPM Task Group, 96 and 111 formalisms were used. For Pediatric Head, Adult Head, and Adult Body Phantom the measured CIDIvol was 61.04 mGy, 48.11 mGy, and 18.08 mGy respectively. The study has shown deviations of 7%, 15%, and 19% between estimated and console-displayed doses for Pediatric Head, Adult Head, and Adult Body scan techniques respectively. The six aspects of image quality measured by QA Phantom were found to be compatible with the specifications of the machine and CTDIvol measured by CTDI Phantom were found within a tolerance limit of ±20%. Hence, the QC and dosimetry of the mentioned machine are within the limit.
基金financially supported by the National Key Research and Development Program of China (No.2020YFA0711800)the National Science Fund for Distinguished Young Scholars (No.51925404)+2 种基金the Graduate Innovation Program of China University of Mining and Technology (No.2023WLKXJ149)the Fundamental Research Funds for the Central Universities (No.2023XSCX040)the Postgraduate Research Practice Innovation Program of Jiangsu Province (No.KYCX23_2864)。
文摘Methane in-situ explosive fracturing technology produces shale debris particles within fracture channels,enabling a self-propping effect that enhances the fracture network conductivity and long-term stability.This study employs X-ray computed tomography(CT)and digital volume correlation(DVC)to investigate the microstructural evolution and hydromechanical responses of shale self-propped fracture under varying confining pressures,highlighting the critical role of shale particles in maintaining fracture conductivity.Results indicate that the fracture aperture in the self-propped sample is significantly larger than in the unpropped sample throughout the loading process,with shale particles tending to crush rather than embedded into the matrix,thus maintaining flow pathways.As confining pressure increases,contact areas between fracture surfaces and particles expand,enhancing the system's stability and compressive resistance.Geometric analyses show flow paths becoming increasingly concentrated and branched under high stress.This resulted in a significant reduction in connectivity,restricting fracture permeability and amplifying the nonlinear gas flow behavior.This study introduces a permeability-strain recovery zone and a novel sensitivity parameter m,delineating stress sensitivity boundaries for permeability and normal strain,with m-value increasing with stress,revealing four characteristic regions.These findings offer theoretical support for optimizing fracturing techniques to enhance resource extraction efficiency.
文摘To obtain two kinds of tomograms at two different X-ray energy ranges simultaneously, we have constructed a dual-energy X-ray photon counter with a lutetium-oxyorthosilicate photomultiplier detector system, three comparators, two microcomputers, and two frequency-voltage converters. X-ray photons are detected using the detector system, and the event pulses are input to three comparators simultaneously to determine threshold energies. At a tube voltage of 100 kV, the three threshold energies are 16, 35 and 52 keV, and two energy ranges are 16 - 35 and 52 - 100 keV. X-ray photons in the two ranges are counted using microcomputers, and the logical pulses from the two microcomputers are input to two frequency-voltage converters. In dual-energy computed tomography (CT), the tube voltage and current were 100 kV and 0.29 mA, respectively. Two tomograms were obtained simultaneously at two energy ranges. The energy ranges for gadolinium-L-edge and K-edge CT were 16 - 35 and 52 - 100 keV, respectively. The maximum count rate of dual-energy CT was 105 kilocounts per second with energies ranging from 16 to 100 keV, and the exposure time for tomography was 19.6 min.
基金The National Natural Science Foundation of China(No.51575256)the Fundamental Research Funds for the Central Universities(No.NP2015101,XZA16003)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘To improve spectral X-ray CT reconstructed image quality, the energy-weighted reconstructed image xbins^W and the separable paraboloidal surrogates（SPS） algorithm are proposed for the prior image constrained compressed sensing（PICCS）-based spectral X-ray CT image reconstruction. The PICCS-based image reconstruction takes advantage of the compressed sensing theory, a prior image and an optimization algorithm to improve the image quality of CT reconstructions.To evaluate the performance of the proposed method, three optimization algorithms and three prior images are employed and compared in terms of reconstruction accuracy and noise characteristics of the reconstructed images in each energy bin.The experimental simulation results show that the image xbins^W is the best as the prior image in general with respect to the three optimization algorithms; and the SPS algorithm offers the best performance for the simulated phantom with respect to the three prior images. Compared with filtered back-projection（FBP）, the PICCS via the SPS algorithm and xbins^W as the prior image can offer the noise reduction in the reconstructed images up to 80. 46%, 82. 51%, 88. 08% in each energy bin,respectively. M eanwhile, the root-mean-squared error in each energy bin is decreased by 15. 02%, 18. 15%, 34. 11% and the correlation coefficient is increased by 9. 98%, 11. 38%,15. 94%, respectively.
文摘Distributed X-ray sources comprise a single vacuum chamber containing multiple X-ray sources that are triggered and emit X-rays at a specific time and location. This process facilitates an application for innovative system concepts in X-ray and computer tomography. This paper proposes a novel electron beam focusing, shaping,and deflection electron gun for distributed X-ray sources.The electron gun uses a dispenser cathode as an electron emitter, a mesh grid to control emission current, and two electrostatic lenses for beam shaping, focusing, and deflection. Novel focusing and deflecting electrodes were designed to increase the number of focal spots in the distributed source. Two identical half-rectangle opening electrodes are controlled by adjusting the potential of the two electrodes to control the electron beam trajectory, and then, multifocal spots are obtained on the anode target. The electron gun can increase the spatial density of the distributed X-ray sources, thereby improving the image quality. The beam experimental results show that the focal spot sizes of the deflected(deflected amplitude 10.5 mm)and non-deflected electron beams at full width at half maximum are 0.80 mm 90.50 mm and 0.55 mm 90.40 mm, respectively(anode voltage 160 kV; beam current 30 mA). The imaging experimental results demonstrate the excellent spatial resolution and time resolution of an imaging system built with the sources, which has an excellent imaging effect on a field-programmable gate array chip and a rotating metal disk.
基金supported by the National Natural Science Foundation of China (Nos. 41602131, 41330313, 41572122, and 41672130)the Fundamental Research Funds for the Central Universities of China (Nos. 17CX02074, 15CX02086A, and 17CX06036)the Research Project Funded by the SINOPEC Corp. (No. P17027-3)
文摘Due to heterogeneous pore distributions within shales,petrophysical properties of shales determined by scanning electron microscopy(SEM) and X-ray computed tomography(CT) methods strongly depend on the observed domain size(analysis scale). In this paper,the influence of the analysis scale on areal and bulk porosities and pore size distribution(PSD) for lacustrine shales from the Dongying sag of Bohai Bay Basin,China were investigated using broad ion beam(BIB)-SEM and X-ray CT methods.The BIB-SEM cross-sections with high imaging resolution(10 nm/pixel) and a large field of view(>1 mm2)mainly describe the 2 D nanoscale pore system in the two shales(samples F41#-2 and Y556#-1),while CTbased 3 D reconstructions with resolutions of 0.42(F41#-1) and 0.5 μm/pixel(H172#-1) reflect the 3 D submicron pore system. The results indicate that the areal(bulk) porosity exhibits a multiple power-law distribution with increasing analysis area(volume),which can be used to extrapolate the porosity of a given area(volume). Based on SEM and CT investigations,the sizes of the minimum representative elementary areas(REAs) and volumes(REVs) were determined respectively,which are closely associated with the heterogeneousness of the pore system. Minimum REAs are proposed to be 2.93×10~4(F41#-2) and 0.91×10~4μm2(Y556#-1),and minimum REVs are 0.016(F41#-1) and 0.027 mm^3(H172#-1). As the analyzed areas(volumes) are larger than the minimum REA(REV),obtained 2 D(3 D) PSDs are comparable to each other and can be considered to reflect the shale PSD. These results provide insights into the porosity and PSD characterization of shales by SEM and X-ray CT methods.
基金supported by the National Basic Research Program of China(2010CB428902)National Natural Science Foundation of China(40876088)
文摘Large areas of muddy sediments on the coastal shelves of China provide important samples for studying climate and ecological changes. Analysis of a large number of such samples, which is essential for systematic study on environmental information recorded in mud areas because of complicated sedimentary environment and variable sedimentary rate, requires a fast and economical method. In this study, we investigated the potential of X-ray fluorescence core scanner （XRFS）, a fast analytical instrument for measuring the elemental concentrations of muddy sediments, and observed a significant correlation between the element concentrations of muddy sediments determined by regular X-ray fluorescence spectrometer （XRF） and XRFS, respectively. The correlations are mainly determined by excitation energy of elements, but also influenced by solubility of element ions. Furthermore, we found a striking link between A1 concentrations and marine-originated organic carbon （MOC）, a proxy of marine primary productivity. This indicates that MOC is partly controlled by sedimentary characteristics. Therefore, XRFS method has a good potential in fast analysis of a large number of muddy sediment samples, and it can also be used to calibrate MOC in ecological study of coastal seas.
