Typical transmission electron

The history of EM (for an overview see table Bl.17,1) can be interpreted as the development of two concepts the electron beam either illuminates a large area of tire sample ( flood-beam illumination , as in the typical transmission electron microscope (TEM) imaging using a spread-out beam) or just one point, i.e. focused to the smallest spot possible, which is then scaimed across the sample (scaiming transmission electron microscopy (STEM) or scaiming electron microscopy (SEM)). In both situations the electron beam is considered as a matter wave interacting with the sample and microscopy simply studies the interaction of the scattered electrons. 

As mentioned above, employment of MWCNT for field emitter will be one of the most important applications of MWCNT. For this purpose, MWCNT is prepared by the chemical purification process [30,38], in which graphite debris and nanoparticles are removed by oxidation with the aid of CuCl2 intercalation [38]. Purified MWCNT is obtained in the form of black and thin "mat" (a flake with thickness of ca. a few hundreds of [im). Figure 7 shows a typical transmission electron microscope (TEM) picture of MWCNT with an open end, which reveals that a cap is etched off and the central cavity is exposed. 

Figure 3.7 (a) Voltammetric response of (A) bamboo MWNTs and (B) high-puritycatalystfree MWNTs in a solution containing 1 mM hydrazine in PBS. (b) Typical transmission electron image of MWNTs in which an iron metal particle sheathed by graphene layers is observed. Such impurities can lead to misinterpretations in... 

Some typical transmission electron micrographs of these polystyrene lattices are shown (Sample 2 and Sample 3) in Figure 10.6. The effects ofthe amount of stabilizer S is the relative amount of stabilizer) on the particle size is strong the more stabilizer applied, the smaller the particles are. It must be emphasized that this effective stabilization of nanopowders by our fluorinated block copolymers is not restricted to polymerization processes, but can be generalized to the fabrication of all organic nanopowders in media with low cohesion energy density, e.g., to the dispersion of dyes, explosives, or drugs. 

Figure 13. Typical transmission electron micrograph of an ultrathin section (about 60nm) of cesium sulfonate groups having 1100 EW. Reproduced from Ref. 28. Copyright 1981 American Chemical Society.

Fig. 7. Typical transmission electron micrographs of 640 nm polystyrene spheres on which one monolayer of Au Si02 nanoparticles has been assembled. The size of the Au cores is 15 nm in all cases. From left to right, the silica shell thicknesses are 8,18, and 28 nm...

Fig. 33. A typical transmission electron micrograph showing the appearance of dislocations (in this case vacancy loops and basal dislocations in M0S2 are visible). 20,000 X. Reprinted with the permission of the Faraday Society (S 7).

Because of the nature of the in situ precipitation, the particles are essentially unagglomerated (as demonstrated by electron microscopy). The mechanism for their growth seems to involve simple homogeneous nucle-ation. Since the particles are separated by polymer, they do not have the opportunity to coalesce. Figure 9.2 shows a typical transmission electron micrograph of such a silica-filled material. The particles are relatively monodisperse, most having diameters in the range of 100-200 A. Similar results have been obtained with other particles formed by sol-gel... 

The carboxylic acid groups were converted first to the potassium salt and then to Co(II) salts by addition of cobalt(II) acetate solution to the copolymer latex with agitation in an ultrasonic bath to produce the latex catalysts listed in Table 1. The latexes were purified by ultrafiltration through a 0.1 im cellulose acetate/nitrate membrane (Millipore) until tiie conductivity of the filtrate at 25 C was constant at 40 x lO" ohm l cm"l. Purified latexes contained 1-2% solids. An upper limit of 3 x 10" for the firaction of Co(II) not bound to the latex was established by addition of 1,10-phenanthroline to the ultrafiltrate and UV-visible spectrophotometric analysis of tiie Co(II) complex. By the same criterion, addition of 6 mol of pyridine per mol of Co(II) to form the active catalysts did not extract cobalt ions from the latex. Thus practically dl of the Co(II) was bound to latex. A typical transmission electron micrograph of catalyst RC-1 is shown in Figure 1. 

Fig. 15.1 shows a typical transmission electron microscopy image of Ca-P04-coated, oxygen-carrying, retrievable nanoreactors. Several variants of the calcium phosphate coating procedure can be employed to yield relatively uniformly coated particles 120-200 nm in diameter (Fig. 15.1). 

Figure 12.3 Chemical structure of cellulose (a), schematic representation of the crystalline and disordered mixed morphology of cellulose before (b) and after (c) isolation of the CNCs, and a typical transmission electron microscopy image of cotton-derived CNCs (d).

Fig. 4.32. Typical transmission electron micrographs of quenched linear polyethylene fractions for indicated molecular weights. Reproduced from [202] with permission. Copyright 1984, John Wiley Sons, Inc.

Figure 1. Typical transmission electron micrographs of fragments of sanq>les ET2.5 (a) and of ET20 (b).

The structure and the surface morphology of the nanocomposite samples were studied using the atomic force microscopy (Solver P-47) and transmission electron microscopy (PEM-100) techniques. Analysis showed that the samples contained the uniformly distributed nanopartides of used materials with sizes of 10-25 nm. Figure 7.2 presents the typical transmission electron microscope image of a nanocomposite sample containing 5% nanopartides MnO. As can be seen, MnO particles are situated on the sample surface. These particles are distributed quite uniformly and have dimensions of about 10 nm, but not exceeding 20 nm. 

Figure 3.3 Typical transmission electron microscopy micrographs (a) 0.5 wt% PtBMA-b-Cso in 0.75 ethyi acetate molar composition (b) 1.0wt% PtBMA-b-Cso in 0.92 ethyl acetate molar composition (c) close up view of a single aggregate of 0.5 wt% PtBMA-fa-Cso In 0.75 ethyl acetate molar...

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