X-ray Talbot-Lau interferometer has been used most widely to perform x-ray phase-contrast imaging with a con- ventional low-brilliance x-ray source, and it yields high-sensitivity phase and dark-field images of sample...X-ray Talbot-Lau interferometer has been used most widely to perform x-ray phase-contrast imaging with a con- ventional low-brilliance x-ray source, and it yields high-sensitivity phase and dark-field images of samples producing low absorption contrast, thus beating tremendous potential for future clinical diagnosis. In this work, by changing the accel- erating voltage of the x-ray tube from 35 kV to 45 kV, x-ray phase-contrast imaging of a test sample is performed at each integer value of the accelerating voltage to investigate the characteristic of an x-ray Talbot-Lau interferometer （located in the Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Japan） versus tube voltage. Ex- perimental results and data analysis show that within a range this x-ray Talbot-Lau interferometer is not sensitive to the accelerating voltage of the tube with a constant fringe visibility of ~ 44%. This x-ray Talbot-Lau interferometer research demonstrates the feasibility of a new dual energy phase-contrast x-ray imaging strategy and the possibility to collect a refraction spectrum.展开更多
Proper parameters for image taking and minimum field number for image processing were investigated to evaluate volume fraction of unhydrated cement（UHC） in both neat cement paste and slag blended cement paste. Our r...Proper parameters for image taking and minimum field number for image processing were investigated to evaluate volume fraction of unhydrated cement（UHC） in both neat cement paste and slag blended cement paste. Our research suggested that magnification 250x was sufficient for the two pastes, and accelerating voltage should be set as 15 kV and 20 kV for BSE image taking of neat cement paste and slag blended cement paste respectively; the minimum field number increased while the total imaging area stayed the same as the magnification increased within certain statistical bias.展开更多
The metal organic deposition(MOD)method was used for the epitaxial growth of the CeO2/La2Zr2O7(LZO)/LZO seed layer structure on a cube-textured Ni5W substrate layer by layer.The material phase and the macro-orientatio...The metal organic deposition(MOD)method was used for the epitaxial growth of the CeO2/La2Zr2O7(LZO)/LZO seed layer structure on a cube-textured Ni5W substrate layer by layer.The material phase and the macro-orientations were analyzed by XRD.The surface morphology and the blocking performance of the buffer layer were investigated by SEM and AES.The grain orientation and the crystallographic growth mode of the CeO2 layer were first characterized by electron backscattering diffraction(EBSD).The uniformly distributed islanded LZO seed layer optimized both the in-plan and the out-plan orientation of the CeO2/LZO buffer layers,and the CeO2/LZO buffer layers with a thickness of 175 nm acted as an efficient Ni,W barrier.The EBSD analysis indicated that the crystallographic orientation of each layer can be obtained at various accelerating voltages for the multilayer sample,the percentage of{001}<110>rotated cube texture of CeO2 layer reaching 97.4%at the accelerating voltage of 15 kV,thus showing epitaxial deposition with a high texture.展开更多
Propellant ionization in the Hall thruster discharge channel is a significant process and has strong influence on the thruster＇s efficiency. In this work, the functional relation has been established between the ioni...Propellant ionization in the Hall thruster discharge channel is a significant process and has strong influence on the thruster＇s efficiency. In this work, the functional relation has been established between the ionization density distribution and the function of the ion energy distribution through the basic equations governing the ion flow in the Hall thruster channel and the method achieved for reconstructing the ionization density distribution inside the channel by ordinary plasma diagnosis of the potential distribution and ion energy spectrum of the plasma jet. The ionization density distributions of single and double charged ions in an ATON-thruster channel have been reconstructed according to the experimental data of the potential distribution along the axis of the channel and the ion energy spectrum of the plasma jet. The agreement between the calculation and experimental results of the percentage of double charged ions proves the validity of our method achieved in this work.展开更多
基金Project supported by the Major State Basic Research Development Program of China(Grant No.2012CB825800)the Science Fund for Creative Research Groups,China(Grant No.11321503)+1 种基金the National Natural Science Foundation of China(Grant Nos.11179004,10979055,11205189,and 11205157)the Japan–Asia Youth Exchange Program in Science(SAKURA Exchange Program in Science)Administered by the Japan Science and Technology Agency
文摘X-ray Talbot-Lau interferometer has been used most widely to perform x-ray phase-contrast imaging with a con- ventional low-brilliance x-ray source, and it yields high-sensitivity phase and dark-field images of samples producing low absorption contrast, thus beating tremendous potential for future clinical diagnosis. In this work, by changing the accel- erating voltage of the x-ray tube from 35 kV to 45 kV, x-ray phase-contrast imaging of a test sample is performed at each integer value of the accelerating voltage to investigate the characteristic of an x-ray Talbot-Lau interferometer （located in the Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Japan） versus tube voltage. Ex- perimental results and data analysis show that within a range this x-ray Talbot-Lau interferometer is not sensitive to the accelerating voltage of the tube with a constant fringe visibility of ~ 44%. This x-ray Talbot-Lau interferometer research demonstrates the feasibility of a new dual energy phase-contrast x-ray imaging strategy and the possibility to collect a refraction spectrum.
基金Funded by the Major State Basic Research Development Program of China(973 Program)(No.2009CB623104)
文摘Proper parameters for image taking and minimum field number for image processing were investigated to evaluate volume fraction of unhydrated cement（UHC） in both neat cement paste and slag blended cement paste. Our research suggested that magnification 250x was sufficient for the two pastes, and accelerating voltage should be set as 15 kV and 20 kV for BSE image taking of neat cement paste and slag blended cement paste respectively; the minimum field number increased while the total imaging area stayed the same as the magnification increased within certain statistical bias.
基金National Basic Research Program"973"of China(2006CB601005)National Natural Science Foundation of China(50771003)National High Technology Research and Development Program of"863"(2009AA032401)
文摘The metal organic deposition(MOD)method was used for the epitaxial growth of the CeO2/La2Zr2O7(LZO)/LZO seed layer structure on a cube-textured Ni5W substrate layer by layer.The material phase and the macro-orientations were analyzed by XRD.The surface morphology and the blocking performance of the buffer layer were investigated by SEM and AES.The grain orientation and the crystallographic growth mode of the CeO2 layer were first characterized by electron backscattering diffraction(EBSD).The uniformly distributed islanded LZO seed layer optimized both the in-plan and the out-plan orientation of the CeO2/LZO buffer layers,and the CeO2/LZO buffer layers with a thickness of 175 nm acted as an efficient Ni,W barrier.The EBSD analysis indicated that the crystallographic orientation of each layer can be obtained at various accelerating voltages for the multilayer sample,the percentage of{001}<110>rotated cube texture of CeO2 layer reaching 97.4%at the accelerating voltage of 15 kV,thus showing epitaxial deposition with a high texture.
文摘Propellant ionization in the Hall thruster discharge channel is a significant process and has strong influence on the thruster＇s efficiency. In this work, the functional relation has been established between the ionization density distribution and the function of the ion energy distribution through the basic equations governing the ion flow in the Hall thruster channel and the method achieved for reconstructing the ionization density distribution inside the channel by ordinary plasma diagnosis of the potential distribution and ion energy spectrum of the plasma jet. The ionization density distributions of single and double charged ions in an ATON-thruster channel have been reconstructed according to the experimental data of the potential distribution along the axis of the channel and the ion energy spectrum of the plasma jet. The agreement between the calculation and experimental results of the percentage of double charged ions proves the validity of our method achieved in this work.
