Scanning transmission electron microscopy concentration

Figure 3-11. (A) Scanning transmission electron microscopy image of tlie Au-nanoparticle (1.4 nm (-reconstituted GOx hybrid. (The arrow indicates the Au-nanoparticle). (B) Cyclic voltammograms corresponding to the bioelectrocatalyzed oxidation of variable concentrations of glucose by tire electrically-contacted Au-nanoparticle-reconstituted GOx-modified electrode. Glucose concentrations correspond to (a) 0 mM, (b) 1 mM, (c) 2 mM, (d) 5 mM, (e) 10 mM. Inset Calibration curve corresponding to the electrocatalytic currents at different glucose concentrations. Reproduced with permission from ref. 41. Copyright 2003, AAAS.

The length of the antiparallel overlap between molecules in a side-polar filament is not firmly established. A 43-nm antiparallel overlap was unique to segments formed from smooth muscle myosin rods by precipitation with divalent cations (Kendrick-Jones et al., 1971). Folded dimers with an approximately 40- to 50-nm antiparallel overlap are formed at salt concentrations <50 mM KCl (Trybus and Lowey, 1984). Both of these observations suggest that the molecule favors a 43-nm overlap. Measurements obtained by scanning transmission electron microscopy, however, show that filaments formed in vitro have one antiparallel dimer per 14.3 nm of filament length, a value that favors a model where adjacent molecules have a 14.3-nm antiparallel overlap (Cross and Engel, 1991) (Fig. 4). The... 

Minor concentrations of foreign compositions at grain boundaries and three-grain junctions in a sintered ceramic can be characterized using transmission electron microscopy (TEM) and electron diffraction, scanning transmission electron microscopy (STEM) with EDS or electron energy loss spectroscopy (EELS), and AES. ... 

One problem with methods that produce polycrystalline or nanocrystalline material is that it is not feasible to characterize electrically dopants in such materials by the traditional four-point-probe contacts needed for Hall measurements. Other characterization methods such as optical absorption, photoluminescence (PL), Raman, X-ray and electron diffraction, X-ray rocking-curve widths to assess crystalline quality, secondary ion mass spectrometry (SIMS), scanning or transmission electron microscopy (SEM and TEM), cathodolumi-nescence (CL), and wet-chemical etching provide valuable information, but do not directly yield carrier concentrations. 

In addition to surface analytical techniques, microscopy, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning tunneling microscopy (STM) and atomic force microscopy (AFM), also provide invaluable information regarding the surface morphology, physico-chemical interaction at the fiber-matrix interface region, surface depth profile and concentration of elements. It is beyond the scope of this book to present details of all these microscopic techniques. 

Major and trace element concentrations in the acidified samples were determined via ICP-MS (inductively coupled plasma mass spectrometry) and ICP-OES (inductively coupled plasma optical emission spectroscopy) at the GSC s Geochemistry Research Laboratory. Dissolved anion concentrations were measured by 1C (ion chromatography) on the unacidified samples, also at the GSC s Geochemistry Research Laboratory. Characterization of the sediment mineralogy and texture by XRD (X-ray diffraction), SEM (scanning electron microscopy) and TEM (transmission electron microscopy) is ongoing. 

Scanning electron microscopy (SEM) data for carbon-black compounds and conductive polymer blends [72c], supported by recent transmission electron microscopy (TEM) evaluations [79,80] (shown in Figure 11.39) were made, they also contradict the assumption of a statistical distribution. We find complete dispersion below the critical volume concentration (I) and a sudden stiucture formation ( branched flocculate chains ) at the critical volume concentration. This structural feature remains at higher concentrations. 

Scanning electron microscopy (SEM) Pig. 10, revealed an increase in the surface concentration of copper domains following additional cure. An increase in the thickness of the copper oxide layer from approximately 700 A to 1300 k was also noted by transmission electron microscopy. Post-processing was considered by the authors to be analogous to sintering wherein, small particles fuse to become a large solid mass. 

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