Transmission electron microscopy experimental

The field of carbon nanotube research was launched in 1991 by the initial experimental observation of carbon nanotubes by transmission electron microscopy (TEM) [151], and the subsequent report of conditions for the synthesis of large quantities of nanotubes [152,153]. Though early work was done on... 

Lastly, gold supported on Mg(OH)2 is very active for CO oxidation even at 200 K [30]. However, it suddenly died after 4 months. Transmission electron microscopy could not clarify the reason because no appreciable change in particle diameter was observed. X-ray scattering due to gold clusters was measured experimentally. The... 

With such a definition, it was found that vfc at 445 K did not change within experimental error as the average Pd particle size, determined by transmission electron microscopy (TEM), was varied between 1.5 and 8.0 nm (Figure 1). Besides, this value of v was also the same as that reported for the ill face of a single crystal of Pd (2), the latter value being itself very much the same on other planes of Pd or on a polycrystalline wire (3). 

It is difficult to evaluate the shape of such dendritic particles experimentally. However, some insight can be gained by atomic force microscopy (AFM) and transmission electron microscopy experiments (TEM). AFM experiments can give information about the overall size of the dendrimers, as shown by De Schryver [43], by spincoating very dilute solutions of dendrimers like 30 on mica, then visualizing single dendrimers. Their height measured in this manner corresponds very well to the diameters calculated by molecular mechanics simulations. First results from TEM measurements also confirm the expected dimensions [44]. Unfortunately, due to resolution limits, up to now direct visual information could not be obtained about the shape of the dendrimers. 

The experimental techniques described above of charge—discharge and impedance are nondestructive. Tear-down analysis or disassembly of spent cells and an examination of the various components using experimental techniques such as Raman microscopy, atomic force microscopy, NMR spectroscopy, transmission electron microscopy, XAS, and the like can be carried out on materials-spent battery electrodes to better understand the phenomena that lead to degradation during use. These techniques provide diagnostic techniques that identify materials properties and materials interactions that limit lifetime, performance, and thermal stabiity. The accelerated rate calorimeter finds use in identifying safety-related situations that lead to thermal runaway and destruction of the battery. 

Transmission electron microscopy (TEM) and birefringence studies of strained and/ or fractured epoxies have revealed more direct experimental evidence that molecular flow can occur in these glasses. Films of DGEBA-DETA ( 11 wt.- % DETA) epoxies, 1 pm thick, were strained directly in the electron microscope and the deformation processes were observed in bright-field TEM 73 110). Coarse craze fibrils yielded in-homogeneously by a process that involved the movement of indeformable 6-9 tan diameter, highly crosslinked molecular domains past one another. The material between such domains yielded and became thinner as plastic flow occurred. 

Figures 5 (a) and (b) show electron micrographs of the RuxSey particles in powder form, Fig. 5.5(a) and in colloidal form, Fig. 5.5(b). The generated particle size in both cases is ca.2 nm. It is, however, interesting that the colloidal route delivers particles with a narrow size distribution. After multiple analysis by EDX performed with transmission electron microscopy (TEM), and/or via Rut-herford backscattering spectroscopy (RBS) we concluded that the stoichiometry of the RuxSey compound corresponds to x 2 and y 1. This is another experimental evidence that the "real" chemical precursor is the intermediate...

In the author s opinion, the better approach to experimentally study the morphology of the silica surface is with the help of physical adsorption (see Chapter 6). Then, with the obtained, adsorption data, some well-defined parameters can be calculated, such as surface area, pore volume, and pore size distribution. This line of attack (see Chapter 4) should be complemented with a study of the morphology of these materials by scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning probe microscopy (SPM), or atomic force microscopy (AFM), and the characterization of their molecular and supramolecular structure by Fourier transform infrared (FTIR) spectrometry, nuclear magnetic resonance (NMR) spectrometry, thermal methods, and possibly with other methodologies. 

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