Scanning electron microscopy summary

The zeolites obtained were characterised by a number of techniques including XRD (Seifert diffractometre JSO Debye-Flex 200, with Cu Ka radiation), DR-FTIR spectroscopy (Matson INFINITY), scanning electron microscopy (SEM, Jeol JSM-840), EDX (coupled to the SEM, Link QX-200) and thermogravimetry. As a summary, the zeolites prepared are crystalline materials, which are only constituted by the desired phase. Table 1 contains the molecular formulas of the zeolites prepared and Table 2 presents their main crystallographic characteristics. 

Fij iiiv H. Summary of the analysis of polished thin seetions using scanning electron microscopy and optical microscopy (after Pike Kemp. 19%). 

In summary, U can be stated that scanning electron microscopy is a very simple and useful technique for charaaerising microfiltration membranes. A clear and concise picture of the membrane can be obtained in terms of the top layer, cross-section and bottom layer. In addition, the porosity and the pore size distribution can be estimated from the photographs. Care must be taken that the preparation technigue does not influence the actual porous structure. 

In Scanning Electron Microscopy (SEM), a probe electron beam (typically a few hundred eV to a few lO s keV energy) is finely focused (down to 10 A capability in some instruments) and scanned over a solid surface. The interaction of the beam with the sample material generates a variety of responses, including fluorescence emission, which can be used for elemental analysis (see the EDS summary). 

Electronic microscopy (EM) plays a key role in the characterization of catalysts. The imderstanding of some aspects of these techniques becomes a sine qua non condition in catalysis [1]. Although the literature is relatively wide in fundamentals and applications [2], this chapter will present a brief summary on scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM). 

The large size of CPOs allows their direct observation. For this purpose, scanning tunneling microscopy (STM) is the best method [32,34]. Electron microscopic analysis is used for phthalocyanine 3 and its derivatives however, most of the porphyrin derivatives are decomposed by electron beam irradiation. Presently, although only a limited number of researchers are able to perform atomic-scale resolution measurement, this powerful analytical method is expected to be used widely in the future. The author reported a summary of STM studies on porphyrins elsewhere [34]. 

FIGURE 11.66 Summary of size ranges covered by various analytical techniques for atmospheric aerosols. TEM, transmission electron microscopy SEM, scanning electron microscope (adapted from Hinds, 1982). 

Figure 17.3.2 Detection limits, sampling depth, and spot size for several surface spectroscopic techniques. XRP (x-ray fluorescence) EMP (electron microprobe) EEL (electron energy loss), SAM (scanning Auger microprobe) STEM (scanning transmission electron microscopy). Other abbreviations in Figure 17.3.1. This figure is meant to provide a graphic summary of the relative capabilities of different methods modem instmments have somewhat better quantitative performance characteristics than the 1986 values given here. [From A. J. Bard, Integrated Chemical Systems, Wiley, New York, 1994, pp. 103, with permission adapted from Texas Instmments Materials Characterizations Capabilities, Texas Instmments, Richardson, TX, 1986, with permission.]...

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