Microscopy analytical

Very much more common is elemental analysis using the x-rays emitted from the specimen in the SEM [23-26, 119-123] and the TEM 

keep the beam from falling on the area to be imaged unless the image is being recorded  

match the maximum allowed specimen dose, the magnification, and the sensitivity of the recording medium. 

When the low dose technique works well, the resolution in the image of a beam sensitive material approaches its theoretical limit (see Section 3.4). What if this is not good enough There are a few possibilities  

Use image processing (see Section 2.8.1) to reduce the effects of noise. 

Increase the maximum electron dose that the specimen can withstand  

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Price, D.M., Reading, M., Caswell, A., Hammiche, A., and PoUock, H.M., Micro-thermal analysis A new form of analytical microscopy, Microsc. Anal., 65, 17, 1998. 

Chassard-Bouchaud C. 1996. Analytical microscopy and environment. Current developments using bioindicators of pollution by stable and radioactive elements. Cell Mol Biol 42(3) 361-383. 

Modern methods of surface microanalysis and analytical microscopy produce analytical information mainly in the form of images. Furthermore, analytical results of distribution analysis, obtained in various ways, by direct sample scanning, discontinuous sampling or even by remote sensing, may be presented by images. 

Budantsev, Arkady Yustianovitch, Professor, Head of Department of Analytical Microscopy, Russian Academy of Sciences, Institute of Theoretical and Experimental Biophysics, Istitutskaya Str., 3, Pushchino, Moscow Region, 142290, Russia, E-mail budantsev mail. ru, Fax (7-0967)790553... 

Loh, A., Some Environmental Applications of Analytical Microscopy , Ph.D. Thesis, University of Illinois, Urbana, Illinois, 1975. 

The phase transitions of cholesteryl nonanoate have been studied with a new apparatus for thermal analytical microscopy. The enantiomer ratio of some chiral sulphoxides can be changed from racemic to a modest preference for one enantiomeric form by dissolution in a cholesteryl ester in its liquid-crystalline ( cholesteric ) state. 5,6-Epoxycholestan-3-yl p-nitrobenzoates exhibit liquid-crystal properties, but 5,6-diols and dibromides are inactive. ... 

Detailed HRTEM characterization of the specimens showed that all metal-ceramic interfaces in the two different nanocomposites had thin ( 1 nm thick) amorphous films (see Fig. 11.5). In addition, occluded particles were found inside the alumina grains which also had thin amorphous films at their interfaces with alumina. Analytical microscopy showed the films to contain Ca, Si, and Al.41 Hamaker coefficients were calculated for metal-ceramic interfaces in the presence of a Si02-based film, which indicated that a stronger attractive force is expected for intergranular films at metal-alumina interfaces,... 

J.F. Faudon, F. Senocq, G. Bergeret, B. Moraveck, and G. Clugnet, Preparation and Characterization of Ni-Pt Catalysts by X-Ray Diffraction Analytical Microscopy andFXAFS, Journal of Catalysis, Vol.144, 1993, pp.460-471. 

Nikon analytical microscopy workstation Microphot SA is adaptable for complex multi-imaging requirements run from a host computer. 

The student should be aware that there is another class of surface analysis instruments based on analytical microscopy, including scanning electron microscopy,... 

Applications of EPMA include elemental analysis of surfaces and of micron-sized features at a surface. The sensitivity of the method is about 0.2 atom%. It provides a rapid, accurate method for compositional analysis of microscopic features. Elemental mapping of the elements present at the surface can also be done, and the composition correlated to topographical maps obtained from an analytical microscopy method, allowing correlation of topographical features of a surface with elemental composition. Like XRF, EPMA is strictly an elemental analysis technique no information on chemical spe-ciation or oxidation state is obtained. AU elements from boron to uranium can be determined. Given that X-rays can escape from depths of 1000 A or so, EPMA has the deepest definition of surface of the techniques discussed in this chapter. In fact, like XRF, it can be considered to be a bulk analysis technique assuming the sample is homogeneous. 

Catalyst surfaces, surfaee eompounds, metals dispersed on supports, and adsorbed molecules are investigated by eleetron spectroseopy, ion speetroscopy, analytical microscopy, and other methods [12, 33]. 

The high-resolution characterization of the various rectorite samples was performed at 200 and 400 Kv in a Jeol-2000 electron microscope. The analytical microscopy was performed in a Jeol-lOOCX machine fitted with a Tracor Northern 5500 x-ray detector. Samples were embedded in resin (6, 7) and microtomed in the direction perpendicular to the basal planes (8). The parent rectorite was intercalated with tetrapropylammonium bromide solutions (TPA-Br) to improve the clay stability in the microscope column. The pillared rectorite was instead dispersed in isopropyl alcohol the clay particles were then separated by ultrasonification and deposited onto copper grids. 

The student should be aware that there is another class of surface analysis instruments based on analytical microscopy, including scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and scanning tunneling microscopy. A discussion of these microscopy techniques is beyond the scope of this chapter. Most industrial materials characterization laboratories will have some combination of electron spectroscopy. X-ray analysis, surface mass spectrometry, and analytical microscopy instrumentation available, depending on the needs of the industry. 

Electron-matter interaction used for analytical microscopy... 

C. E. Lyman, Scanning Electron Microscopy, X-ray Microanalysis and Analytical Microscopy (Plenum, New York, 1990). 

The tungsten filament source has a limit to the beam current that can be obtained in a small spot. Replacing it with a lanthanum hexaboride (LaB6) gun provides a beam about 30 times brighter. This results in an improved signal to noise ratio and allows better resolution at high scan speeds. The increased current is also useful for analytical microscopy. A disadvantage is that this gun requires a better vacuum which must be provided by the addition of an ion pump to the gun chamber. 

The smallest sources, the field emission sources, are most useful for high resolution STEM (Section 3.2.1) and analytical microscopy. Because of the extremely severe radiation damage under these conditions and the need for ultrahigh vacuum, they are almost never used for polymers. 

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