Sample morphology

It should be noted that during CL observations intensity variations may arise due to sample morphology (e.g., surface roughness), which may lead to nonuniform excitation and to local variations in optical absorption and reflecdon losses. 

Extraction procedure Sample morphology Solvent Irganox 1425 recovery range (%) Time (h)... 

Fig. 4.17 Optical micrographs showing the effect of a lateral increase (from left to right) in anodization current density on sample morphology, (b) Surface and (c) cross-section of a p-type (100) substrate anodized in the dark (4x1014 crrf3, 60s, 10V, 1 1 HF 50% ethanol) using a set-up with a small, local ohmic back contact, as shown in (a). An SEM micrograph of the center of (c) is shown in Fig. 6.11c. SEM images of regions A and B are shown in Figs. 6.11c and 2.4c, respec-...

Westmaii, A. Huth-Fehre, T. Demirev, P.A. Sundqvist, B.U.R. Sample Morphology Effects in MALDl-MS of Proteins. J. Mass Spectrom. 1995, 30, 206-211. 

The dependence of the drift mobility p on the electric field is represented by formula p (p-E1/2/kTcf) which corresponds to the Pool-Frenkel effect. The good correspondence between experimental and theoretical quantity for Pool-Frenkel coefficient 3 was obtained. But in spite of this the interpretation of the drift mobility in the frame of the Coulombic traps may be wrong. The origin of the equal density of the positive and negative traps is not clear. The relative contribution of the intrinsic traps defined by the sample morphology is also not clear [17,18]. This is very important in the case of dispersive transport. A detailed analysis of the polymer polarity morphology and nature of the dopant molecules on mobility was made by many authors [55-58]. 

Concerning the above-mentioned critical quantities the authors have in fact established (i) that irrespective of stress level damage is apparently initiated at a critical creep strain ec of 3 to 3.5% (ii) that a notable deviation of creep data from the potential law starts just at this strain level and (iii) that although the strain rate dev/df is a function of stress, the minimum in the Sherby-Dorn plot also occurs (for the tubular specimens) at ec. The postulated changes in sample morphology at about the time when the strain values started to deviate from Findley s equation, were in fact seen by these and other authors [42,52], who detected in U PVC deformed micro-cavities later... 

Figure 10. Effect of sample morphology on the stress-strain properties of a PTMO/PTMT elastomeric system containing 44% by tot hard segment...

Impact tests made with the DYNATUP system indicate that the impact process is not restricted to a simple mechanism. Although means are available to isolate specific characteristics of the fracture process, this information is of little value unless it is specifically correlated with sample morphology. When the detailed test data are related to morphology, an understanding of the complex mechanisms operating during fracture is possible. 

The solid supports used in this study were macroporous co-polymers of vinylpyridine and styrene crosslinked with divinylbenzene. Polymers of this type in the form of beads are available commercially (e.g. Reillex 425) and were also prepared for this study by Purolite. For spectroscopic studies, a more convenient sample morphology was required and thin-film polymers of similar stoichiometry were synthesised by the group of Sherrington at the University of Strathclyde. Full details of the methods used to prepare thin film polymers are reported elsewhere.11 To generate the ion exchange resin, the pyridyl functionalities of the polymer were quatemised with methyl iodide (Eq 1). 

FID contains information about the chemical environment of each nucleus. The curve-fitting for the observed FIDs gives the individual spin-spin relaxation characteristics in different phases crystalline, amorphous and interfacial.4-9 Such a resolution into several components has been long attempted on a broadline spectrum of solid PE.10-13 These results will reflect the sample morphologies. 

Changes in the amorphous relaxation behaviour with rising temperature exhibited a monotonous reduction of the integral width, independent of sample morphology, while a crystalline relaxation change is unique for each sample. Thus, the complete analysis of XH FID allows us to discuss chain mobility of amorphous and crystalline phase independently. 

Here, the origins of these relaxation processes can be predicted based on a comparison of the spectrum and sample morphology. The regular stacking of... 

There may be contributions to the conductivity from several different types of carrier, notably electrons and holes (a hole is an electron vacancy carrying an equivalent positive charge) in electronic conductors, and cation and anion pairs in ionic conductors. Theories of conduction aim to explain how n and fj. are determined by molecular structure and how they depend on such factors as temperature and applied field. In addition, in polymers the mobility will be affected by the sample morphology. Just as a large range of conductivity is observed for different materials so there is a large range of mobility values. Data for a selection of systems are displayed on the mobility chart (Fig. 4.2). 

Nalwa (1997). A shorter summary is provided in the Proceedings of the 81st Nobel Symposium (Salaneck et al., 1993) that led on to the award of the Nobel Prize for the discovery of metallic PAc. Mullen and Wegner (1998) deal with the related area, not discussed here, of conjugated oligomers with chemical structures and physical properties similar to those of conjugated polymers, but with simpler sample morphology. 

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