Electron loss images

Qualmann and Kessels have reported the synthesis of carborane-containing lysine dendrimers (123) (Fig. 72), with a better defined number of boron atoms, for use as protein labels in immunocytochemistry using electron microscopic techniques such as electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI).149... 

Sowada and Warman (1982) have described a dc conductivity method for Ar gas at 295 K and 45 atm. Following a 20-ns pulse of irradiation, the conductivity rises to a peak at -50 ns, due to the Ramsauer effect, before settling to a plateau, which is ascribed to thermal conductivity since the collecting field is very low. Since there is little electron loss, the conductivity profile is proportional to the mobility profile this in turn can be considered a kind of image of collision frequency as a function of electron energy. The time to reach the conductivity plateau, -150 ns, is the measure of thermalization time in the present case. At a density of -9 X 1021 cm-3, the conductivity maximum vanishes, indicating the disappearance of the Ramsauer minimum according to Sowada and Warman. 

Figure 11. The HRTEM micrograph of VO2 4.(C16H33NH2)0.34 nanotubes (a rolled up superlattice of V205 layers separated by amphiphilic moities with amine head group) (39). (a) Side-on view of three nanotubes with unclosed caps and (b) cross-section of the nanotubes left zero-loss (electron energy) image, right vanadium (electron energy loss) image. [Courtesy of F. Krumeich and R. Nesper, ETH.]...

Spectroscopy produces spectra which arise as a result of interaction of electromagnetic radiation with matter. The type of interaction (electronic or nuclear transition, molecular vibration or electron loss) depends upon the wavelength of the radiation (Tab. 7.1). The most widely applied techniques are infrared (IR), Mossbauer, ultraviolet-visible (UV-Vis), and in recent years, various forms ofX-ray absorption fine structure (XAFS) spectroscopy which probe the local structure of the elements. Less widely used techniques are Raman spectroscopy. X-ray photoelectron spectroscopy (XPS), secondary ion imaging mass spectroscopy (SIMS), Auger electron spectroscopy (AES), electron spin resonance (ESR) and nuclear magnetic resonance (NMR) spectroscopy. 

Bohmer J, Rahmann H. 1991. Ultrastructural aluminium detection in amphibian tissues by electron spectroscopic imaging and electron energy-loss spectroscopy. J Microsc 162 115-122. 

Xie X, Yokel RA, Markesbery WR. 1994. Application of electron energy loss spectroscopy and electron spectroscopic imaging to aluminum determination in biological tissue. Biol Trace Elem Res 40 39-48. 

There is another significant feature of these images. Because electrons interact with the electron clouds around the atomic nuclei, the electron microscope image contrast is, in fact, a map of the electron density in the crystal, projected in a direction parallel to the electron beam. However, as greatest electron density usually occurs close to atomic nuclei, the image can also be interpreted in terms of projected atoms without significant loss of precision. 

Reimer L, Fromm I, and Rennekamp R (1988) Operation modes of electron spectroscopic imaging and electron energy-loss spectroscopy in a transmission electron microscope. Ultramicroscopy 24 339-354. 

Figure 14.6 Zero-loss energy-filtered transmission electron microscopy images of MDMO-PPV PCNEPV blends with low (a), medium (b), and high (c) molecular weights of PCNEPV.(Reprinted with permission from Ref [53]. Copyright 2007, Wiley-VCH VerlagCmbH.)...

E.M. Linares, C.A.P. Leite, L.F. Valadares, C.A. SUva, C.A. Rezende, F. Galembeck, Molecular mapping by low-energy-loss energy-filtered transmission electron microscopy imaging. Analytical Chemistry 81 (2009) 2317-2324. 

Recently Bevolo (1985b) has exploited the high spatial resolution inherent in electron beam excitation to create electron energy loss images in reflection geometry of hydrogenated scandium and gadolinium surfaces. The characteristic plasmon... 

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