Microdiffraction studies of small crystallites

Identification of nano-crystallites (&lt;5 nm) on a high surface area support such as a catalyst is critical in the development of improved catalysts. Bright field imaging of small particles can be obscured by the phase contrast of the support. A common approach is to utilize annular dark field microscopy; however, wide angle scattering from the high surface area support can easily appear in the annular dark field image. Often one utilizes the energy dispersive detector to identify conclusively the nanosized metal crystallite, but this approach is troublesome when crystallites are very thin since counting times for imaging can become excessive. One technique for avoiding some of these difficulties is to utilize microdiffraction to identify the crystallite and then to image the crystallite by axial dark field microscopy.In the work reported here, the imaging was performed with a dedicated VG HB-5 scanning transmission electron microscope.</jats:p

Ecologically Friendly Water-based Polyuretnanes Materials

Environmentally friendly and economically feasible materials for multipurpose purposes on the basis of waterborn polyuretnanes with using naturally renewable and available raw materials as fragments of the polymer's macrochain and structure, combining this with using advantages of are created