High-resolution electron structural transformations

In the present study, we synthesized in zeolite cavities Co-Mo binary sulfide clusters by using Co and Mo carbonyls and characterized the clusters by extended X-ray absorption fine structure (EXAFS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and high resolution electron microscopy (HREM). The mechanism of catalytic synergy generation in HDS is discussed. 

The power spectrum of high-resolution electron microscopy (HREM) images contains usefiil diffraction information, which can be used for studying defects, small particles or other local structures that are difficult to study by diffraction alone. For thin specimens below a certain thickness, the Fourier transform of the image intensity (/ (5)) can be related to the Fourier transform of the potential (F (5), the structure factor) ... 

A number of functional materials based on rare earth oxides have been developed in various fields. Up to 1990, many review articles describing rare earth oxides have been reported and several intensive articles deal the properties e.g. preparation, structure and transformation and have been published early nineteen nineties. In these ten years, much progress has been made in the characterization of rare earth oxides fi om high-resolution electron microscopy (HREM), as well as in a unique preparation of ultra-fine particles and in the theoretical calculation. 

Taking into account the mathematical properties of the Fourier transformation, the electron density p r), defining the high-resolution material structure (i.e., the atomic configuration), can be determined only if the complex function Aq) (modulus and phase) is known over a large volume in q space. On the other hand, if the amplitude Aq) is only determined within a rather small volume in q space around = 0, equation (8-2) exclusively yields the low-resolution features ofthe structure. 

High-resolution transmission electron microscopy (HREM) is the technique best suited for the structural characterization of nanometer-sized graphitic particles. In-situ processing of fullerene-related structures may be performed, and it has been shown that carbonaceous materials transform themselves into quasi-spherical onion-like graphitic particles under the effect of intense electron irradiation[l 1],... 

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