Inhomogeneous distribution

Myers A B, Tchenio P and Moerner W E 1994 Vibronic spectroscopy of single molecules exploring electronic-vibrational frequency correlations within an inhomogeneous distribution J. Lumin. 58 161-7... 

We have demonstrated that due to inhomogeneous distribution of both reaction partners in the micelles, the pseudophase model leads to erroneous estimates of the second-order rate Constantin the micellar pseudophase, so that conclusions regarding the medium of the reaction cannot be derived through this model. However, analysis of substituent effects and endo-exo ratios of the Diels-Alder adducts indicate that the reaction experiences a water-like medium. 

For DTB films obtained by CVT inhomogenous distribution of out-of-framework cations and admixture capture ai e obseiwed. The aim of the present work is to use imaging X-ray photoelectron spectroscopy (i-XPS) for chemical state mapping which enable future optimization of the CVT technology. The P, O and Hg content in the DTB may be varied during the CVT. 

Figure 8.33. Comparison of inhomogeneous distribution with fragment data from explosively driven cylinders.

In this case the foreign cations and water molecules are inhomogeneously distributed and the Mn - O layers are stacked with no periodicity. In some regions of the lattice, where no foreign cations or water molecules are present, the distance between the layers becomes quite small (comparable with Mn50R), while in regions with separating cations or water molecules the Mn - O sheets are at a... 

A great variety of suitable polymers is accessible by polymerization of vinylic monomers, or by reaction of alcohols or amines with functionalized polymers such as chloromethylat polystyrene or methacryloylchloride. The functionality in the polymer may also a ligand which can bind transition metal complexes. Examples are poly-4-vinylpyridine and triphenylphosphine modified polymers. In all cases of reactively functionalized polymers, the loading with redox active species may also occur after film formation on the electrode surface but it was recognized that such a procedure may lead to inhomogeneous distribution of redox centers in the film... 

Fig. 4 shows the SEM images of SWNTs purified by the thermal oxidation and acid-treated. Fig. 4(a) shows a SEM image of the raw soot. In addition to the bundle of SWNTs, carbonaceous particles are shown in the figure. These stractural features mi t be causal by various in the arcing process because of an inhomogeneous distribution of catalysts in the anodes [7]. It can be seen that the appearance of SWNTs was curled and quite different fiom that of MWNTs. Fig. 4(b) shows a decrease of amorphous carbons after oxidation. The basic idea of the selective etching is that amorphous carbons can be etched away more easily than SWNTs due to the faster oxidation reaction rate [2]. Since the CNTs are etched away at the same time, the yield is usually low. The transition metals can be etched away by an add treatment. Fig. 4(c) shows the SEM image of the acid-treated sample, where the annealed sample was immersed in 10 % HCl. 

OS 92] [R 32] [P 72/The iodate-arsenous acid reachon proceeds to one of two stationary states in different parts of the capillary when an electrical field of specific strength is applied [68]. Accordingly, a spatially inhomogeneous distribution of reaction products is generated along the capillary. 

FIGURE 5.6 Example of improper manual application resulting in an inhomogeneous distribution of the sample over the entire length of the unacceptable band, documentation after chromatography at UV 366 nm. 

Since SERS and SERRS are substance specific, they are ideal for characterisation and identification of chromatographically separated compounds. SE(R)R is not, unfortunately, as generally applicable as MS or FUR, because the method requires silver sol adsorption, which is strongly analyte-dependent. SE(R)R should, moreover, be considered as a qualitative rather than a quantitative technique, because the absolute activity of the silver sol is batch dependent and the signal intensity within a TLC spot is inhomogeneously distributed. TLC-FTIR and TLC-RS are considered to be more generally applicable methods, but much less sensitive than TLC-FT-SERS FT-Raman offers p,m resolution levels, as compared to about 10p,m for FTIR. TLC-Raman has been reviewed [721],... 

One common difficulty when applying the E-model is the need to know the turbulent dissipation rate e for the flow. Moreover, because e will have an inhomogeneous distribution in most chemical reactors, the problem of finding e a priori is non-trivial. In most... 

The structure in Fig. 8a is also similar to the structures of the dihydrides, MRu3(CO)j 3H2 (M = Fe100 or Ru253 ), shown in Fig. 9. The six carbonyl groups present in the basal plane of the dihydrides are inhomogeneously distributed and this gives rise to C—C contacts of the order of 2.5 - 2.6 A which results in considerable steric compression in this region. 

Other aspects of the inhomogeneous distribution of "active sites" are discussed by Wollast and Chou (25), who suggest that their earlier estimates of residual layer thickness are minima, because restricting the residual layer to the vicinity of active sites would mean that more of the reaction takes place over a smaller area, increasing the thickness of the residual layer there. "If a residual layer exists, then it would probably cover less than 10 of the total surface and accordingly the value for the calculated thickness would be increased proportionally" (p. 

Room temperature phosphorescence can be observed from dried proteins. Sheep wool keratin(47) has a phosphorescence lifetime of 1.4 s. Six lyophilized proteins were shown to exhibit phosphorescence at room temperature.(48) The spectra were diffuse, and the lifetime was non-single-exponential, which the authors interpreted as due to inhomogeneous distribution of tryptophans. As the protein was hydrated, the phosphorescence lifetime decreased. This decrease occurred over the same range of hydration where the tryptophan fluorescence becomes depolarized. Hence, these results are consistent with the idea that rigidity of the site contributes to the lifetimes. 

Treatment of wood with multi-component systems is likely to result in separation of the components when large wood samples are treated. This has been likened to the action of a chromatography column (Schneider, 1995). This is a significant problem that is often only encountered during scale-up of laboratory-based studies, where satisfactory results were previously obtained on small wood samples. Similarly, treatment of large wood samples can often lead to considerable variability in results due to inhomogeneous distribution, which again may not be evident with small samples treated under laboratory conditions. 

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