Imaging blood vessels is of importance for determining the vascular distribution of organs and tumors.Phase-contrast X-ray imaging can reveal the vessels in much more detail than conventional X-ray absorption method.V...Imaging blood vessels is of importance for determining the vascular distribution of organs and tumors.Phase-contrast X-ray imaging can reveal the vessels in much more detail than conventional X-ray absorption method.Visualizing murine liver microvasculature ex vivo with phase-contrast X-ray imaging was performed at Shanghai Synchrotron Radiation Facility.Barium sulfate and physiological saline were used as contrast agents for the blood vessels.Blood vessels of <Φ20μm could be detected by replacing resident blood with physiological saline or barium sulfate.An entire branch of the portal vein (from the main axial portal vein to the ninth generation of branching) could be captured in a single phase-contrast image.It is demonstrated that selective angiography based on phase contrast X-ray imaging,with a physiological material of low Z elements (such as saline) being the contrast agent,is a viable imaging strategy.Further efforts will be focused on using the technique to image tumor angiogenesis.展开更多
An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and ...An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and difficulty of fabrication by a state of the art technique. On the basis of phase grating diffraction, a detecting model of the scintillator screen was built for analysing the phase and absorption information of objects. According to the analysis, a new method of phase retrievals based on two-images and the optimal structure of screen were presented.展开更多
Analysis ofZ phase precipitation in 2205 duplex stainless steel aged at 700 and 750 ~C has been investigated systematically. The experimental results showed that X phase forms prior to the precipitation of δ phase an...Analysis ofZ phase precipitation in 2205 duplex stainless steel aged at 700 and 750 ~C has been investigated systematically. The experimental results showed that X phase forms prior to the precipitation of δ phase and disappears once tr phase starts to precipitate. This phenomenon indicates that a phase nucleated and consumed the Z phase. The δ phase nucleated mairdy at ferrite/austenite interface and grew inwards into the ferrite phase. The morphology of a phase reveals a coral-like structure at the temperature of 700 ℃ for 120 min followed by quenching in water. The decomposition of ferrite occurs via the following eutectoid reaction： F---＊o＇＋y2. The selected area diffraction pattern of zone axes is[3 1 3-][3 1 3], indicating a characteristic orientation relationship between X phase and δ-ferrite.展开更多
The phase separation in Ni75AlxV25-x alloys incorporated with the elastic stress was investigated using the microscopic phase-field model. The final morphology ofγ' andθis similar in spatial alignment, but the v...The phase separation in Ni75AlxV25-x alloys incorporated with the elastic stress was investigated using the microscopic phase-field model. The final morphology ofγ' andθis similar in spatial alignment, but the volume fraction ofγ' phase increases and that ofθdecreases as the Al concentration increases. For the small elastic interactions of early-stage phase separation, the coarsening ofγ' andθcan be approximated by a linear growth law as predicated by Lifshitz and Slyozov and Wangner (LSW) theory. As the elastic interactions increase at late-stage coarsening, the growth rate decreases, and the growth presents quick increase at early-stage and slows down at late-stage.展开更多
基金Supported by National Basic Research Program of China (973 Program Grant No.2010CB834305)
文摘Imaging blood vessels is of importance for determining the vascular distribution of organs and tumors.Phase-contrast X-ray imaging can reveal the vessels in much more detail than conventional X-ray absorption method.Visualizing murine liver microvasculature ex vivo with phase-contrast X-ray imaging was performed at Shanghai Synchrotron Radiation Facility.Barium sulfate and physiological saline were used as contrast agents for the blood vessels.Blood vessels of <Φ20μm could be detected by replacing resident blood with physiological saline or barium sulfate.An entire branch of the portal vein (from the main axial portal vein to the ninth generation of branching) could be captured in a single phase-contrast image.It is demonstrated that selective angiography based on phase contrast X-ray imaging,with a physiological material of low Z elements (such as saline) being the contrast agent,is a viable imaging strategy.Further efforts will be focused on using the technique to image tumor angiogenesis.
基金supported by the National Natural Science Foundation of China (Grant Nos. 60232090 and 10774102)the Science & Technology Project from Shenzhen Government of China (Grant Nos. 2008340 and 200717)
文摘An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and difficulty of fabrication by a state of the art technique. On the basis of phase grating diffraction, a detecting model of the scintillator screen was built for analysing the phase and absorption information of objects. According to the analysis, a new method of phase retrievals based on two-images and the optimal structure of screen were presented.
基金Funded by the School Foundation of North University of China,the Science and Technology Projects of Jiancaoping District of Taiyuan Citythe Natural Science Foundation of Shanxi Province,China(Nos.2013011014-1,2015011036,2014011024-1)the National Natural Science Foundation of China(No.51201154)
文摘Analysis ofZ phase precipitation in 2205 duplex stainless steel aged at 700 and 750 ~C has been investigated systematically. The experimental results showed that X phase forms prior to the precipitation of δ phase and disappears once tr phase starts to precipitate. This phenomenon indicates that a phase nucleated and consumed the Z phase. The δ phase nucleated mairdy at ferrite/austenite interface and grew inwards into the ferrite phase. The morphology of a phase reveals a coral-like structure at the temperature of 700 ℃ for 120 min followed by quenching in water. The decomposition of ferrite occurs via the following eutectoid reaction： F---＊o＇＋y2. The selected area diffraction pattern of zone axes is[3 1 3-][3 1 3], indicating a characteristic orientation relationship between X phase and δ-ferrite.
基金Project (50071046) supported by the National Natural Science Foundation of ChinaProject (2002AA331051)supported by the National Hi-Tech Research and Development Program of ChinaProject(CX200507) supported by the the Doctorate Foundation of Northwestern Polytechnical University
文摘The phase separation in Ni75AlxV25-x alloys incorporated with the elastic stress was investigated using the microscopic phase-field model. The final morphology ofγ' andθis similar in spatial alignment, but the volume fraction ofγ' phase increases and that ofθdecreases as the Al concentration increases. For the small elastic interactions of early-stage phase separation, the coarsening ofγ' andθcan be approximated by a linear growth law as predicated by Lifshitz and Slyozov and Wangner (LSW) theory. As the elastic interactions increase at late-stage coarsening, the growth rate decreases, and the growth presents quick increase at early-stage and slows down at late-stage.
