Electron microscopic

Fig. Vni-3. (a) Atomic force microscope (AFM) and (b) transmission electron microscope (TEM) images of lead selenide particles grown under arachidic acid monolayers. (Pi Ref. 57.)...

Egerton R F 1986 Electron Energy-Loss Spectroscopy in the Electron Microscope (New York Pienum)... 

This text covers quantitative analysis by electron energy-loss spectroscopy in the electron microscope along with instrumentation and applicable electron-scattering theory. 

As noted earlier, most electron diffraction studies are perfonned in a mode of operation of a transmission electron microscope. The electrons are emitted themiionically from a hot cathode and accelerated by the electric field of a conventional electron gun. Because of the very strong interactions between electrons and matter, significant diffracted intensities can also be observed from the molecules of a gas. Again, the source of electrons is a conventional electron gun. 

ESEM environmental scanning electron microscope ESI electron spectroscopic imaging... 

LVSEM low-voltage scanning electron microscope MTF modulation transfer function... 

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. 

Zach J 1989 Design of a high-resolution low-voltage scanning electron microscope Opf/k 83 30-40... 

Menetret J-F, Hofmann W, Schroder R R, Rapp G and Goody R S 1991 Time-resolved cryo-electron microscopic study of the dissociation of actomyosin Induced by photolysis of photolablle nucleotides J. Mol. Biol. 219 139-43... 

Frank J 1973 The envelope of electron microscopic transfer functions for partially coherent Illumination Optik ZS 519-27... 

Crewe A V, Wall J and Welter L M 1968 A high resolution scanning transmission electron microscope J. Appl. Phys. 39 5861-8... 

Light microscope Scanning electron microscope Transmission electron microscope Scanning probe microscope... 

Iwahashi M, Kikuchi K, Achiba Y, Ikemoto I, Araki T, Mochida T, Yokoi S-l, Tanaka A and Iriyama K 1992 Morphological study ofthin-film systems of pure fuiierene (Cgg) and some other amphiphilic compounds on the electron microscopic scale Langmuir 8 2980-4... 

Most tests of the validity of the BET area have been carried out with finely divided solids, where independent evaluation of the surface area can be made from optical microscopic or, more often, electron microscopic observations of particle size, provided the size distribution is fairly narrow. As already explained (Section 1.10) the specific surface obtained in this way is related to the mean projected diameter through the equation... 

Figure 1,1 Individual polystyrene molecules as seen in an electron microscope. Tails are the result of shadow casting, which is used to enhance the visibility of the particles. [From M. J. Richardson, Proc. Royal Soc. 279A 50 (1964).]...

The polyethylene crystals shown in Fig. 4.11 exist as hollow pyramids made up of planar sections. Since the solvent must be evaporated away prior to electron microscopic observation, the pyramids become buckled, torn, and/ or pleated during the course of sample preparation. While the pyramidal morphology is clearly evident in Fig. 4.1 la, there is also evidence of collapse and pleating. Likewise, the ridges on the apparently planar crystals in Fig. 4.1 lb are pleats of excess material that bunches up when the pyramids collapse. 

A scanning electron microscope can also be equipped with additional instmmentation for electron-excited x-ray analysis (9). In many systems, this is performed in the mode known as energy dispersive x-ray analysis (edx). Other common acronyms for this method are eds for energy dispersive spectroscopy or edax for energy dispersive analysis of x-rays. 

Fig. 13. Scanning electron microscope (sem) photographs of Parylene C-coated printed circuit conductor peeled to demonstrate the adhesion of the...

Testing. Chemical analyses are done on all manufactured abrasives, as well as physical tests such as sieve analyses, specific gravity, impact strength, and loose poured density (a rough measure of particle shape). Special abrasives such as sintered sol—gel aluminas require more sophisticated tests such as electron microscope measurement of a-alumina crystal si2e, and indentation microhardness. 

Extraterrestrial dust particles can be proven to be nonterrestrial by a variety of methods, depending on the particle si2e. Unmelted particles have high helium. He, contents resulting from solar wind implantation. In 10-)J.m particles the concentration approaches l/(cm g) at STP and the He He ratio is close to the solar value. Unmelted particles also often contain preserved tracks of solar cosmic rays that are seen in the electron microscope as randomly oriented linear dislocations in crystals. Eor larger particles other cosmic ray irradiation products such as Mn, Al, and Be can be detected. Most IDPs can be confidently distinguished from terrestrial materials by composition. Typical particles have elemental compositions that match solar abundances for most elements. TypicaUy these have chondritic compositions, and in descending order of abundance are composed of O, Mg, Si, Ee, C, S, Al, Ca, Ni, Na, Cr, Mn, and Ti. 

The very high powers of magnification afforded by the electron microscope, either scanning electron microscopy (sem) or scanning transmission electron microscopy (stem), are used for identification of items such as wood species, in technological studies of ancient metals or ceramics, and especially in the study of deterioration processes taking place in various types of art objects. 

One technique that does probe the foam stmcture directly is cryomicroscopy. The foam is rapidly frozen, and the soHd stmcture is cut open and imaged with an optical or electron microscope (14). Such methods are widely appHcable and provide a direct image of the foam stmcture however, they destroy the sample and may also perturb the foam stmcture in an uncontroUed manner during the freezing. 

Gelatin stmctures have been studied with the aid of an electron microscope (23). The stmcture of the gel is a combination of fine and coarse interchain networks the ratio depends on the temperature during the polymer-polymer and polymer-solvent interaction lea ding to bond formation. The rigidity of the gel is approximately proportional to the square of the gelatin concentration. Crystallites, indicated by x-ray diffraction pattern, are beUeved to be at the junctions of the polypeptide chains (24). 

Fig. 7. Electron microscope view of Gilson synthetic opal each sphere is j p.m in diameter.

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