Although there has been much research of cracks of the cement-based materials using optical and electron microscopy two-dimensional (2D) imaging methods, the real three-dimensional (3D) crack shapes have not previousl...Although there has been much research of cracks of the cement-based materials using optical and electron microscopy two-dimensional (2D) imaging methods, the real three-dimensional (3D) crack shapes have not previously been revealed. Thanks to the focused ion beam (FIB) tomography and the follow-up image processing, two 3D subsurface cracks and a cluster of inner cracks were picked out and discussed in this research. It was found that the subsurface crack (its length is about 15 part, width about 1-5 prn, and opening about 1 ~tm) was much larger than the inner crack (its length and width are about 1-5 pro, opening is from 200 nm to 1 pan), which arose from the sample preparation process. Besides, it was revealed that most of the inner cracks were in the form of clusters.展开更多
Advances in fabrication of mesoscopic membrane sensors with unique structures and morphologies inside anodic alumina membrane （AAM） nanochannels have led to the development of various methods for detecting, visualiz...Advances in fabrication of mesoscopic membrane sensors with unique structures and morphologies inside anodic alumina membrane （AAM） nanochannels have led to the development of various methods for detecting, visualizing, adsorbing, filtering, and recovering ultra-trace concentrations of toxic metal ions, such as Hg^2＋ and Pb^2＋, in water and blood. These often ＂one-pot＂ screening methods offer advantages over conventional methods in that they do not require sophisticated instruments or laborious sample preparation. In the present study, we fabricated two mesoscopic membrane sensors for naked-eye detection, recognition, filtration, and recovery of Hg^2＋ and Pb^2＋ in biological and environmental samples. These sensors were characterized by the dense immobilization of organic colorants on the mesopore surfaces of silica nanotubes that were constructed using the nanochannels of an AAM as a scaffold. We confirmed that the nanotubes were oriented along the long axis of the AAM nanochannels, open at both ends, and completely and uniformly filled with organic colorants; also, the dense immobilization of the organic colorants did not affect the speed of ion-to-ligand binding events. We used simple, desk-top, flow-through assays to assess the suitability of the developed membrane sensors for detection, removal, and filtration of Hg^2＋ and Pb^2＋ with respect to recyclability and continuous monitoring. Removal of the target ions from biological fluids was assessed by means of flow cytometric analysis. Our results demonstrate the potential of our membrane sensors to be used for preventing the health risks associated with exposure to toxic metal ions in the environment and blood.展开更多
基金sponsored jointly by the foundation of National Basic Research Program of China ("973" Program) (Grant No. 2009CB623203)National Natural Science Foundation of China (Grant No. 51008072)+1 种基金Doctoral Program of Higher Education of China (Grant No.200802861029)SRF for ROCS,SEM
文摘Although there has been much research of cracks of the cement-based materials using optical and electron microscopy two-dimensional (2D) imaging methods, the real three-dimensional (3D) crack shapes have not previously been revealed. Thanks to the focused ion beam (FIB) tomography and the follow-up image processing, two 3D subsurface cracks and a cluster of inner cracks were picked out and discussed in this research. It was found that the subsurface crack (its length is about 15 part, width about 1-5 prn, and opening about 1 ~tm) was much larger than the inner crack (its length and width are about 1-5 pro, opening is from 200 nm to 1 pan), which arose from the sample preparation process. Besides, it was revealed that most of the inner cracks were in the form of clusters.
文摘Advances in fabrication of mesoscopic membrane sensors with unique structures and morphologies inside anodic alumina membrane （AAM） nanochannels have led to the development of various methods for detecting, visualizing, adsorbing, filtering, and recovering ultra-trace concentrations of toxic metal ions, such as Hg^2＋ and Pb^2＋, in water and blood. These often ＂one-pot＂ screening methods offer advantages over conventional methods in that they do not require sophisticated instruments or laborious sample preparation. In the present study, we fabricated two mesoscopic membrane sensors for naked-eye detection, recognition, filtration, and recovery of Hg^2＋ and Pb^2＋ in biological and environmental samples. These sensors were characterized by the dense immobilization of organic colorants on the mesopore surfaces of silica nanotubes that were constructed using the nanochannels of an AAM as a scaffold. We confirmed that the nanotubes were oriented along the long axis of the AAM nanochannels, open at both ends, and completely and uniformly filled with organic colorants; also, the dense immobilization of the organic colorants did not affect the speed of ion-to-ligand binding events. We used simple, desk-top, flow-through assays to assess the suitability of the developed membrane sensors for detection, removal, and filtration of Hg^2＋ and Pb^2＋ with respect to recyclability and continuous monitoring. Removal of the target ions from biological fluids was assessed by means of flow cytometric analysis. Our results demonstrate the potential of our membrane sensors to be used for preventing the health risks associated with exposure to toxic metal ions in the environment and blood.
