Carbon, electron diffraction pattern

Although conventional electron-probe microanalysis appears to be unsuitable for analysis of the exposed surface layer of atoms in an alloy catalyst, recent developments have shown that X-ray emission analysis can still be used for this purpose (89, 90). By bombarding the surface with high energy electrons at grazing incidence, characteristic Ka radiation from monolayer quantities of both carbon and oxygen on an iron surface was observed. Simultaneously, information about the structure of the surface layer was obtained from the electron diffraction pattern. 

Fig. 5.16 (A) Bright-field TEM image and (B) element mapping carbon (brighter contrast corresponds to higher concentration of carbon) of ZnO synthesized in aqueous solution at 37 °C in pH 8 buffer for 4 h in the presence of 1.2 mgmL-1 of gelatin. The inset shows the electron diffraction pattern taken parallel to the platelet normal. (Reprinted with permission from [77], Copyright (2006) American Chemical Society).

Experimental results. Some carbon fibre specimens reveal several orders of 001 particularly in electron diffraction patterns Figure 15 shows a plot of (3 against l2, equation (3), for an electron diffraction pattern from the skin region of a high-modulus material. L(oOl)> usually referred to as Lc, is 3.5 nm and a = 2%. A full description of electron-diffraction analysis in several similarly heterogeneous carbon fibres has been published (23). Figure 15 also includes a plot from the 001 electron diffraction profiles of a carbon whisker, an exceptionally perfect graphite material. This specimen, with an Lc of 10 nm, has zero distortion, and represents the only case where we have found no distortion in a fibrous specimen. 

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],...

FIGURE 3.18 HRTEM image of PFA-P7-H carbons. An inset is a corresponding electron diffraction pattern. The image just below the electron diffraction pattern is a noise-filtered image taken from the area indicated by a square. 

Figure 4. Carbon filaments [24] occur in several varieties, differing in the relative arrangement of the graphene units. The orientation is determined by the facetting of the metal catalyst particle (dark). The bottom SEM image shows a spaghetti pile of carbon libers of tubular orientation. The reaction system was methanol on silver, the catalysts were particulate impurities of metals other than silver. The selected area of electron diffraction pattern shows the ring pattern for turbostratic graphite.

Figure 7 Characterization of silver nanoparticles produced by AG4 clone, (a) TEM micrograph of silver nanocrystal morphologies obtained from AG4 clone, (b c) TEM micrographs of silver nanoparticles with AG4 peptides. Inset in (b) is electron diffraction pattern from [111] beam direction for fee crystal, (d) Edge of truncated silver crystal, (e) EDX spectrum indicative for the presence of silver, Cu, and carbon are due to grid. (Reproduced by permission of Nature Publishing Group (www.nature.com))...

Figure 6 (a) SEM image of SWNTs produced by arc-discharge method using Ni Y (4.2 1 at.%) catalyst (scale bar 1 pm). (Reprinted with permission from Ref. 20. 1997 Macmillan Magazines Ltd.) (h) Electron diffraction pattern of carbon nanotubes produced by arc-discharge method. (Reprinted with permission from Y. Saito, T. Yoshikawa, S. Bandow, M. Tomita, and T. Hayashi, Phys. Rev. B., 1993, 48, 1907. 1993 by the American Physical Society)... 

The small probe size allows the selection of an individual nanostructme and reduction of the background in the electron diffraction pattern from the surrounding materials. An example is given in Section 3.5 for the stmctme characterization of individual carbon nanotubes (CNT) by electron diffraction. 

However, in some reports, electron diffraction patterns of the carbonitride films that were indexed as P-C3N4 structure " were later observed to fit to other carbon phases. It was also shown that the published diffraction... 

Figure 5.17 shows a HREM image of a carbon allotrope having a zerodimensional (point) polymer of carbon observed at tire lower part of postshock sample I. The characteristic of the electron diffraction pattern of this type consists of two-dimensional asymmetric (hk) bands and symmetric (0001) reflections of tlie graphite structure and did not alter with tlie angle of tlie incident electron beam. In general, such patterns can be obtained when llie particle is a spherical shell, tlrat is, a zero-dimensional characteristic. Therefore,... 

Figure 5.6. Lower-magnification HREM image and electron diffraction pattern of the particle of y-carbon sampled from the lower central part of postshock sample I...

Figure 5.15. Electron diffraction patterns (a) and (b) were taken from the graphite region and spherical carbon particle in Fig. 5.14a, respectively.

Figure 5.17. (a) IIREM image of a carbon sphere sampled from the lower outer part of postshock sample I. (b) Electron diffraction pattern. The arrow indicates the starting point of the secondaiy graphitic shell growth. 

All the electron diffraction patterns (Fig. 3) taken from individual carbon needles are indexed by the /lO/ and /ikO spots for hexagonal symmetry. The patterns always show strong (00/) spots when the needle axes arc perpendicular to the [001] axis, supporting the idea of a coaxial arrangement of graphitic tubes. As shown in Fig. 2, two side portions of each tube (indicated by shading and labelled V ) will be oriented so that the... 

FIG. 3 Electron diffraction patterns from individual microtubules of graphitic carbon. The patterns show mm2 symmetry, and are indexed by multiple superpositions of hO/ -type reflections and hM reflections of graphite crystal. The needle axes are horizontal, a, Superposition of three sets of [hkO] spots taken from a seven-sheet tubule, b, Superposition of four sets of hkO) spots from a nine-sheet tubule. 

FIGURE 11.1 Electron diffraction patterns of the linear chain carbon films (a-c), the distribution of electron diffraction intensity, its atomic arrangement (g), the Langmuir-Blodgett multi-layered film diffraction patterns (d,e). 

FIGURE 11.2 TEM image of oriented carbon film with a single crystal on it (X 10,000) and its electron diffraction pattern (a), Raman spectrum of the same film (b). 

A new material consisting of sp -carbon which is characterized by a special electron diffraction pattern and DOVS distribution has been developed. This material is obtained by ion-assisted deposition from pulsed carbon plasmas. 

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