External root resorption can induce the degeneration of dental cementum and dentine and may extend towards the pulp reductive. Digital subtraction radiography can function as a useful tool in diagnosing degenerative c...External root resorption can induce the degeneration of dental cementum and dentine and may extend towards the pulp reductive. Digital subtraction radiography can function as a useful tool in diagnosing degenerative carious lesions. This study investigated the diagnostic value of digital subtraction radiography in detecting external root resorption. This was a descriptive study conducted using the lab trial method. Artificially-induced external root resorption was created in different sizes at the coronal and apical aspects of 20 premolar teeth. Digital radiographs were obtained of each tooth under standard conditions and these radiographs were subtracted by imaging devices. The subtracted images and the digital radiographs were observed by three radiologists. Chi-square, Kappa test, and Z-test were used to analyze the data. The mean of general sensitivity of digital subtraction radiography and direct digital radiography was low in diagnosing 0.05 mm lesions (Sen = 35%), yet, the accuracy index was good for all lesions (Acc ≥ 65%). Other diagnostic parameters were also acceptable. Both types of radiography worked better in diagnosing coronal than apical lesions (P > 0.05). The interpreters (observers) showed a better performance in diagnosing external root resorption using digital subtraction radiography compared to digital radiography. Both modalities were exact and accurate in detecting 0.05 mm lesions as well as other lesions. However, the results of digital subtraction radiography were not significantly different from those of direct digital radiography.展开更多
Directional solidification of Al-15% （mass fraction） Cu alloy was investigated by in situ and real time radiography which was performed by Shanghai synchrotron radiation facility （SSRF）. The imaging results reveal...Directional solidification of Al-15% （mass fraction） Cu alloy was investigated by in situ and real time radiography which was performed by Shanghai synchrotron radiation facility （SSRF）. The imaging results reveal that columnar to equiaxed transition （CET） is provoked by external thermal disturbance. The detaching and floating of fragments of dendrite arms are the prelude of the transition when the solute boundary layer in front of the solid-liquid interface is thin. And the dendrite triangular tip is the fracture sensitive zone. When the conditions are suitable, new dendrites can sprout and grow up. This kind of dendrite has no obvious stem and is named anaxial columnar dendrites.展开更多
A high energy X-ray digital radiography(DR)nondestructive testing(NDT)system has been developed to detect the operating state of a driving mechanism.The system consists of five main subsystems,namely,X-ray generator,i...A high energy X-ray digital radiography(DR)nondestructive testing(NDT)system has been developed to detect the operating state of a driving mechanism.The system consists of five main subsystems,namely,X-ray generator,image intensifier,image processor,mechanical platform and control subsystem.Owning to the mechanical platform,the X-ray generator and image intensifier are able to rotate around the vertical axis from 0°to 360°in 35 s and move along vertical axis within the range of 500 mm in 20 s.The 450 kV X-ray generator provides a maximum 100 mm penetration depth and a coverage angle of 40°,and the resolution of the scanned image is 66 lp/cm.As is indicated by its applications,the system is featured with fast scanning speed,wide detection range and high imaging quality.It can be applied to inspect the defects in the driving mechanism as well.展开更多
目的：探讨直接数字化摄影（DR）技术在尘肺病检查和诊断方面的应用价值。方法选择来我院欲提交诊断的20世纪60～80年代参加国防施工的复退军人及部分经职业健康查体筛选的企业工人共计811例，同时拍摄高千伏（HkV）胸片及DR胸片，部分...目的：探讨直接数字化摄影（DR）技术在尘肺病检查和诊断方面的应用价值。方法选择来我院欲提交诊断的20世纪60～80年代参加国防施工的复退军人及部分经职业健康查体筛选的企业工人共计811例，同时拍摄高千伏（HkV）胸片及DR胸片，部分加照CT扫描胸片，并对二组胸片进行质量及尘肺病诊断一致性等方面的比较。结果二组胸片的质量对比发现：DR胸片总体质量优于高千伏胸片，尤其DR胸片的一级片率明显高于 HkV胸片，DR胸片的三级片率明显低于HkV胸片，且差异有统计学意义（ P ＜0．05）；DR胸片在图像清晰度及肺部微细结构显示方面较好，两组胸片的诊断结果基本一致，尘肺患者胸片在小阴影形态、总体密集度、分布范围方面无明显差别。结论 DR胸片质量好于HkV胸片，三级片率明显低于HkV胸片；DR摄影可用于尘肺病检查与分期诊断。展开更多
文摘External root resorption can induce the degeneration of dental cementum and dentine and may extend towards the pulp reductive. Digital subtraction radiography can function as a useful tool in diagnosing degenerative carious lesions. This study investigated the diagnostic value of digital subtraction radiography in detecting external root resorption. This was a descriptive study conducted using the lab trial method. Artificially-induced external root resorption was created in different sizes at the coronal and apical aspects of 20 premolar teeth. Digital radiographs were obtained of each tooth under standard conditions and these radiographs were subtracted by imaging devices. The subtracted images and the digital radiographs were observed by three radiologists. Chi-square, Kappa test, and Z-test were used to analyze the data. The mean of general sensitivity of digital subtraction radiography and direct digital radiography was low in diagnosing 0.05 mm lesions (Sen = 35%), yet, the accuracy index was good for all lesions (Acc ≥ 65%). Other diagnostic parameters were also acceptable. Both types of radiography worked better in diagnosing coronal than apical lesions (P > 0.05). The interpreters (observers) showed a better performance in diagnosing external root resorption using digital subtraction radiography compared to digital radiography. Both modalities were exact and accurate in detecting 0.05 mm lesions as well as other lesions. However, the results of digital subtraction radiography were not significantly different from those of direct digital radiography.
基金Project(51001074)supported by the National Natural Science Foundation of ChinaProject(12ZR1414500)supported by Shanghai Municipal Natural Science Fund of ChinaProject(2012CB619505)supported by the National Basic Research Program of China
文摘Directional solidification of Al-15% （mass fraction） Cu alloy was investigated by in situ and real time radiography which was performed by Shanghai synchrotron radiation facility （SSRF）. The imaging results reveal that columnar to equiaxed transition （CET） is provoked by external thermal disturbance. The detaching and floating of fragments of dendrite arms are the prelude of the transition when the solute boundary layer in front of the solid-liquid interface is thin. And the dendrite triangular tip is the fracture sensitive zone. When the conditions are suitable, new dendrites can sprout and grow up. This kind of dendrite has no obvious stem and is named anaxial columnar dendrites.
文摘A high energy X-ray digital radiography(DR)nondestructive testing(NDT)system has been developed to detect the operating state of a driving mechanism.The system consists of five main subsystems,namely,X-ray generator,image intensifier,image processor,mechanical platform and control subsystem.Owning to the mechanical platform,the X-ray generator and image intensifier are able to rotate around the vertical axis from 0°to 360°in 35 s and move along vertical axis within the range of 500 mm in 20 s.The 450 kV X-ray generator provides a maximum 100 mm penetration depth and a coverage angle of 40°,and the resolution of the scanned image is 66 lp/cm.As is indicated by its applications,the system is featured with fast scanning speed,wide detection range and high imaging quality.It can be applied to inspect the defects in the driving mechanism as well.
文摘目的：探讨直接数字化摄影（DR）技术在尘肺病检查和诊断方面的应用价值。方法选择来我院欲提交诊断的20世纪60～80年代参加国防施工的复退军人及部分经职业健康查体筛选的企业工人共计811例，同时拍摄高千伏（HkV）胸片及DR胸片，部分加照CT扫描胸片，并对二组胸片进行质量及尘肺病诊断一致性等方面的比较。结果二组胸片的质量对比发现：DR胸片总体质量优于高千伏胸片，尤其DR胸片的一级片率明显高于 HkV胸片，DR胸片的三级片率明显低于HkV胸片，且差异有统计学意义（ P ＜0．05）；DR胸片在图像清晰度及肺部微细结构显示方面较好，两组胸片的诊断结果基本一致，尘肺患者胸片在小阴影形态、总体密集度、分布范围方面无明显差别。结论 DR胸片质量好于HkV胸片，三级片率明显低于HkV胸片；DR摄影可用于尘肺病检查与分期诊断。
