Transmission electron diffraction pattern

Fig. 4.6. XRD of PQT-12 (a) pressed pellet of precipitated polymer from polymerization (b) pressed pellet annealed at 140 °C (c) as-cast 0.2-pm thin film (d) 0.2-pm thin film annealed at 135 °C and (e) transmission electron diffraction pattern of PQT-12 film on carbon grid [36],...

Structure analysis. The particles were suspended in alcohol and put on a carbon substrate. They were examined in a Philips 301 electron microscope. Bright field, dark field and interference image micrographs on a high resolution stage were taken as well as transmission electron diffraction patterns. The lattice parameter of powders was determined by X-ray diffraction using Cu Ka radiation. 

Fig. 1.1 Transmission electron diffraction pattern obtained from a vapor deposited thin film of amorphous As Seg 2 As Teg.

Figure 16-17. Left transmission electron micrograph of small single crystals of Ooct-OPV5 scale bar 5 pnt. The arrows indicate the 6-axis direction. Right electron diffraction pattern of the same single crystals. The arrow indicates the 613 relteclion spot (crysial dimensions 5x40 pm2 Philips STiiM CM 12 operated at 120 kV. lnslilul Charles Sudron, Strasbourg).

Analytical electron microscopy of individual catalyst particles provides much more information than just particle size and shape. The scanning transmission electron microscope (STEM) with analytical facilities allows chemical analysis and electron diffraction patterns to be obtained from areas on the order of lOnm in diameter. In this paper, examples of high spatial resolution chemical analysis by x-ray emission spectroscopy are drawn from supported Pd, bismuth and ferric molybdates, and ZSM-5 zeolite. 

Transmission electron microscopy (TEM) resembles optical microscopy, except that electromagnetic instead of optical lenses are used to focus an electron beam on the sample. Two modes are available in TEM, a bright-freld mode where the intensity of the transmitted beam provides a two-dimensional image of the density or thickness of the sample, and a dark-field mode where the electron diffraction pattern is recorded. A combination of topographic and crystallographic information, including particle size distributions, can be obtained in this way [32],... 

The transmission electron microscopy (TEM) and correlated electron diffraction patterns of quenched QAB2-4 alloy is shown in Figure 2. When annealed at 773K, by selected-area electron diffraction (SAED) patterns at transmission electron microscopy appears as a bright continuous ring, indicating an amorphous phase. 

Electron diffraction patterns are usually produced with transmission electron microscopes. These instruments are composed of several magnetic lenses. The main lens is the objective lens, which, in addition to forming the first magnified image of the specimen, also produces the first diffraction pattern. This original pattern is then magnified by the other lenses of the microscope so as to produce the final diffraction patterns on the screen or on a camera. 

Fig. 4 Transmission electron micrographs of a highly facetted mostly triangular gold particles, b a hexagonal particle, c electron diffraction pattern of the triangular particle showing that it is a single crystal. Diffraction from the (111), (220), (311), (331), (422) planes are identified...

Important data on the structure of the films were obtained in an analysis of electron diffraction patterns recorded directly in the transmission electron microscope. In all cases, the diffraction patterns had the form of diffuse halos, which indicate that nanoparticles are in the amorphous state [30]. The fact that the nanoparticles are amorphous is in all probability due to the exceedingly fast cooling of nanometer drops after the expansion of the plasma cloud. Estimates of the cooling rate of nanodrops at the instant of their hardening give values of up to 107K/sec. 

Fig. 27. Transmission electron micrograph of a fine duplex amorphous-fcc alloy containing 8 a/o Mn (a) bright-field image, (b) electron diffraction pattern as well as course duplex amorphous-fcc alloy containing 12 a/o Mn (c) bright-field image, (d) electron diffraction pattern [128, 129],...

This is possible because the projection lens system, which for clarity was not shown in Figure 4.7, is normally included behind the objective lens and below the source image plane. This lens system allows the projection of both the diffraction pattern and the specimen image on the observation screen. In Figure 4.8, [50] the electron diffraction pattern of a Fe thin film is shown. In Figure 4.9, the transmission electron micrograph of the mordenite included in the sample CMT-C (see Table 4.1), where fiber-like crystals of mordenite are seen, is shown [51],... 

Fig. 6.5. X-Ray diffraction of AP-CVD ZnO F film deposited at 400°C [15] (top) Transmission electron micrograph and electron diffraction patterns of an AP-CVD ZnO F film deposited at 400°C [24] (bottom left) SEM micrograph of an AP-CVD ZnO F film deposited at 400°C [15] (bottom right). Reprinted with permission from...

Figure 11. Electron microscopy data for Nu-13. A transmission electron micrograph demonstrates the presence of three crystal morphologies. Lattice parameters derived from electron diffraction patterns for each crystal type confirm the composition of Nu-13 as a mixture of (a) ZSM-12,...

X-ray and electron diffraction techniques have been used to obtain the data on epitaxy. X-ray diffraction methods are particularly useful for thick oxide films and have the advantage of giving diffraction patterns from both the oxide film and the metal suhstrate. For oxide films less than several hundred Angstroms thick, electron diffraction techniques are necessary in most cases, hi general, an electron diffraction pattern is not obtained from the metal substrate unless the oxide film is extremely thin, the surface is only partially covered with oxide, or the metal surface is rough. Reflection type diffraction techniques have been used with bulk specimens and transmission techniques with thin specimens and stripped oxide films from bulk metal specimens. Bach technique has its special advantages and limitations, but these will not be discussed here. 

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