Understanding the structure and working principle of brain neural networks requires three-dimensional reconstruction of brain tissue samples using array tomography method.In order to improve the reconstruction perform...Understanding the structure and working principle of brain neural networks requires three-dimensional reconstruction of brain tissue samples using array tomography method.In order to improve the reconstruction performance,the sequence of brain sections should be collected with silicon wafers for subsequent electron microscopic imaging.However,the current collection of brain sections based on silicon substrate involve mainly manual collection,which requires the involvement of automation techniques to increase collection efficiency.This paper presents the design of an automatic collection device for brain sections.First,a novel mechanism based on circular silicon substrates is proposed for collection of brain sections;second,an automatic collection system based on microscopic object detection and feedback control strategy is proposed.Experimental results verify the function of the proposed collection device.Three objects(brain section,left baffle,right baffle)can be detected from microscopic images by the proposed detection method.Collection efficiency can be further improved with position feedback of brain sections well.It has been experimentally verified that the proposed device can well fulfill the task of automatic collection of brain sections.With the help of the proposed automatic collection device,human operators can be partially liberated from the tedious manual collection process and collection efficiency can be improved.展开更多
Based on the waveform data of 5,076 local earthquakes recorded at 25 stations in Xinjiang during the period from 2009 to 2014 and the observation reports provided by the Xinjiang Digital Seismic Network,a data set of ...Based on the waveform data of 5,076 local earthquakes recorded at 25 stations in Xinjiang during the period from 2009 to 2014 and the observation reports provided by the Xinjiang Digital Seismic Network,a data set of 19,140 attenuation factors t*is obtained by fitting the high-frequency attenuation of S-wave spectra with a genetic algorithm. The spatial distribution of Q_S is determined by inverting the t*data with seismic tomography. The results show that the average Q0 in eastern Tianshan is 520,and there is a significant correlation between the Q_S value distribution or attenuation characteristics it disclosed and the surface structure of the study area. The Q_S value is lower in the intersection area of the mountain basin which is located on the north and south sides of the Tianshan Mountains,and the high Q_S distribution is more concentrated inside the Tianshan orogenic belt. The M≥6. 0 earthquakes have been basically located in the Low-Q_S region since 1900. 24 high heat flow points in eastern Tianshan are located at the north and south of Tianshan Mountains where low Q_S exists,indicating a negative correlation. In addition,there is a positive correlation between the velocity structure and the attenuation structure in the study area,which reflects the consistency of the 2-D attenuation structure with the velocity structure and the two-dimensional density structure.展开更多
Aim: To assess the quality of high-resolution CT section planes(HRCT), multi-planar reformation(MPR) and 3-dimensional volume rendered computer tomography(3D-CTVR) were here used in the fine differential diagnosis of ...Aim: To assess the quality of high-resolution CT section planes(HRCT), multi-planar reformation(MPR) and 3-dimensional volume rendered computer tomography(3D-CTVR) were here used in the fine differential diagnosis of ossicular chain in the case of conductive hearing loss with intact tympanic membrane.Methods: Here, 17 cases of otosclerosis and 22 cases of ossicular chain deformity were selected. All patients had normal external ear canals,intact tympanic membranes, conductive hearing loss, type A tympanograms, and negative Gelle's tests. The respective radiological reports of the status of the ossicles via 3 protocols were compared to surgical findings. The quantitative assessments of the representation of different segments of the ossicular chain were based on a 3-point scoring system.Results: MPR and CTVR imaging both showed the integrity of whole ossicular chain well. MPR and CTVR imaging were found to be superior to section planes with respect to showing the superstructure of the stapes and malformations(P > 0.05).Conclusion: CTVR and MPR imaging were found to be better able to show the whole ossicular chain in the conductive hearing loss with normal tympanic membranes. Furthermore, the use of these techniques can have profound contributive value in the differential diagnosis of otosclerosis and ossicular chain absence or malformation.展开更多
The cross-sectional area (CSA) of small pulmonary vessels can be quantified by CT, which is a reliable method of evaluating vascular alterations in such vessels. However, the optimal number of slices required for accu...The cross-sectional area (CSA) of small pulmonary vessels can be quantified by CT, which is a reliable method of evaluating vascular alterations in such vessels. However, the optimal number of slices required for accurate quantitation remains unknown. We evaluated relationships among all slices at 10-mm interval and all slices at 3-cm interval, 6-cm interval, and 3-slices and found the closest correlation (0.939) between all slices at 10-mm intervals and 3-cm intervals. Thus, all slices at 3-cm intervals are suitable for accurately measuring CSA.展开更多
Three-dimensional(3D)structural analysis is an important field in physical and biological sciences.There exist two groups of electron microscopy methods that are capable of providing 3D structural information of an ob...Three-dimensional(3D)structural analysis is an important field in physical and biological sciences.There exist two groups of electron microscopy methods that are capable of providing 3D structural information of an object,i.e.,electron tomography and depth sectioning.Electron tomography is capable of resolving atoms in all three dimensions,but the accuracy in atomic positions is low and the object size that can be reconstructed is limited.Depth sectioning methods give high positional accuracy in the imaging plane,but the spatial resolution in the third dimension is low.In this work,electron tomography and depth sectioning are combined to form a method called multiple-section local-orbital tomography,or nLOT in short.The nLOT method provides high spatial resolution and high positional accuracy in all three dimensions.The object size that can be reconstructed is extended to a million atoms.The present method establishes a foundation for the widespread application of atomic electron tomography.展开更多
This paper initially applied the non-destructive evaluation-computerized tomography and the fractal theory to research the feature of wood fracture. Pinus elliottii, Populus×canadensis cv. ‘I-214’ and Larix gme...This paper initially applied the non-destructive evaluation-computerized tomography and the fractal theory to research the feature of wood fracture. Pinus elliottii, Populus×canadensis cv. ‘I-214’ and Larix gmelinii were choosed as samples. The author established the logarithm-logarithm relationship between the section area of wood fracture and its location, then defined the slope-D_L regressed by the two factors above as the section variation fractal dimension of wood fracture. The results showed: the non-destructive evaluation-computerized tomography can effectively analysis the feature of wood fracture. All the samples exist an marked linear relationship between the section area of fracture and its location, D_L is a new effective parameter to quantitatively characterize the feature of wood fracture, the delta of -2 described the complexity of fracture surface of wood. Due to the anisotropy and variation of wood properties, D_L is the statistically fractal dimension. All the results are tested by the statistic software——SARS, there exists remarkable difference between the D_L from different species. The average fractal dimension of fracture surface of Pinus elliottii is 2.25, Populus×canadensis cv. ‘I-214’ is 2.46, Larix gmelinii is 2.65.展开更多
基金supported in part by the National Natural Science Foundation of China(61873268,62025307,U1913209)the Beijing Natural Science Foundation(JQ19020)。
文摘Understanding the structure and working principle of brain neural networks requires three-dimensional reconstruction of brain tissue samples using array tomography method.In order to improve the reconstruction performance,the sequence of brain sections should be collected with silicon wafers for subsequent electron microscopic imaging.However,the current collection of brain sections based on silicon substrate involve mainly manual collection,which requires the involvement of automation techniques to increase collection efficiency.This paper presents the design of an automatic collection device for brain sections.First,a novel mechanism based on circular silicon substrates is proposed for collection of brain sections;second,an automatic collection system based on microscopic object detection and feedback control strategy is proposed.Experimental results verify the function of the proposed collection device.Three objects(brain section,left baffle,right baffle)can be detected from microscopic images by the proposed detection method.Collection efficiency can be further improved with position feedback of brain sections well.It has been experimentally verified that the proposed device can well fulfill the task of automatic collection of brain sections.With the help of the proposed automatic collection device,human operators can be partially liberated from the tedious manual collection process and collection efficiency can be improved.
基金jointly funded by the Contract Oriented Work Task for Seismic Situation in 2017(2017010104)Science for Earthquake Resilience(XH17041Y)Fund of Earthquake Agency of Xinjiang Uygur Autonomous Region(201401)
文摘Based on the waveform data of 5,076 local earthquakes recorded at 25 stations in Xinjiang during the period from 2009 to 2014 and the observation reports provided by the Xinjiang Digital Seismic Network,a data set of 19,140 attenuation factors t*is obtained by fitting the high-frequency attenuation of S-wave spectra with a genetic algorithm. The spatial distribution of Q_S is determined by inverting the t*data with seismic tomography. The results show that the average Q0 in eastern Tianshan is 520,and there is a significant correlation between the Q_S value distribution or attenuation characteristics it disclosed and the surface structure of the study area. The Q_S value is lower in the intersection area of the mountain basin which is located on the north and south sides of the Tianshan Mountains,and the high Q_S distribution is more concentrated inside the Tianshan orogenic belt. The M≥6. 0 earthquakes have been basically located in the Low-Q_S region since 1900. 24 high heat flow points in eastern Tianshan are located at the north and south of Tianshan Mountains where low Q_S exists,indicating a negative correlation. In addition,there is a positive correlation between the velocity structure and the attenuation structure in the study area,which reflects the consistency of the 2-D attenuation structure with the velocity structure and the two-dimensional density structure.
文摘Aim: To assess the quality of high-resolution CT section planes(HRCT), multi-planar reformation(MPR) and 3-dimensional volume rendered computer tomography(3D-CTVR) were here used in the fine differential diagnosis of ossicular chain in the case of conductive hearing loss with intact tympanic membrane.Methods: Here, 17 cases of otosclerosis and 22 cases of ossicular chain deformity were selected. All patients had normal external ear canals,intact tympanic membranes, conductive hearing loss, type A tympanograms, and negative Gelle's tests. The respective radiological reports of the status of the ossicles via 3 protocols were compared to surgical findings. The quantitative assessments of the representation of different segments of the ossicular chain were based on a 3-point scoring system.Results: MPR and CTVR imaging both showed the integrity of whole ossicular chain well. MPR and CTVR imaging were found to be superior to section planes with respect to showing the superstructure of the stapes and malformations(P > 0.05).Conclusion: CTVR and MPR imaging were found to be better able to show the whole ossicular chain in the conductive hearing loss with normal tympanic membranes. Furthermore, the use of these techniques can have profound contributive value in the differential diagnosis of otosclerosis and ossicular chain absence or malformation.
文摘The cross-sectional area (CSA) of small pulmonary vessels can be quantified by CT, which is a reliable method of evaluating vascular alterations in such vessels. However, the optimal number of slices required for accurate quantitation remains unknown. We evaluated relationships among all slices at 10-mm interval and all slices at 3-cm interval, 6-cm interval, and 3-slices and found the closest correlation (0.939) between all slices at 10-mm intervals and 3-cm intervals. Thus, all slices at 3-cm intervals are suitable for accurately measuring CSA.
基金supported by Basic Science Center Project of the National Natural Science Foundation of China(52388201)the National Natural Science Foundation of China(51525102)。
文摘Three-dimensional(3D)structural analysis is an important field in physical and biological sciences.There exist two groups of electron microscopy methods that are capable of providing 3D structural information of an object,i.e.,electron tomography and depth sectioning.Electron tomography is capable of resolving atoms in all three dimensions,but the accuracy in atomic positions is low and the object size that can be reconstructed is limited.Depth sectioning methods give high positional accuracy in the imaging plane,but the spatial resolution in the third dimension is low.In this work,electron tomography and depth sectioning are combined to form a method called multiple-section local-orbital tomography,or nLOT in short.The nLOT method provides high spatial resolution and high positional accuracy in all three dimensions.The object size that can be reconstructed is extended to a million atoms.The present method establishes a foundation for the widespread application of atomic electron tomography.
文摘This paper initially applied the non-destructive evaluation-computerized tomography and the fractal theory to research the feature of wood fracture. Pinus elliottii, Populus×canadensis cv. ‘I-214’ and Larix gmelinii were choosed as samples. The author established the logarithm-logarithm relationship between the section area of wood fracture and its location, then defined the slope-D_L regressed by the two factors above as the section variation fractal dimension of wood fracture. The results showed: the non-destructive evaluation-computerized tomography can effectively analysis the feature of wood fracture. All the samples exist an marked linear relationship between the section area of fracture and its location, D_L is a new effective parameter to quantitatively characterize the feature of wood fracture, the delta of -2 described the complexity of fracture surface of wood. Due to the anisotropy and variation of wood properties, D_L is the statistically fractal dimension. All the results are tested by the statistic software——SARS, there exists remarkable difference between the D_L from different species. The average fractal dimension of fracture surface of Pinus elliottii is 2.25, Populus×canadensis cv. ‘I-214’ is 2.46, Larix gmelinii is 2.65.
