A wool fabric has been subjected to an atmospheric-pressure treatment with a helium plasma for 30 seconds. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry confirmed removal of the covalently-bound fatty acid layer (F-layer) from the surface of the wool fibers, resulting in exposure of the underlying, hydrophilic protein material. Dye uptake experiments were carried out at 50°C to evaluate the effects of plasma on the rate of dye uptake by the fiber surface, as well as give an indication of the adsorption characteristics in the early stages of a typical dyeing cycle. The dyes used were typical, sulfonated wool dyes with a range of hydrophobic characteristics, as determined by their partitioning behavior between water and n-butanol. No significant effects of plasma on the rate of dye adsorption were observed with relatively hydrophobic dyes. In contrast, the relatively hydrophilic dyes were adsorbed more rapidly (and uniformly) by the plasma-treated fabric. It was concluded that adsorption of hydrophobic dyes on plasma-treated wool was influenced by hydrophobic interactions, whereas electrostatic effects predominated for dyes of more hydrophilic character. On heating the dyebath to 90°C in order to achieve fiber penetration, no significant effect of the plasma treatment on the extent of uptake or levelness of a relatively hydrophilic dye was observed as equilibrium conditions were approached.

Coherent diffraction imaging (CDI) typically requires that the source should be highly coherent both laterally and longitudinally. In this paper, we demonstrate that lateral and longitudinal partial coherence can be successfully included in a CDI reconstruction algorithm simultaneously using experimental X-ray data. We study the interplay between lateral partial coherence and longitudinal partial coherence and their relative influence on CDI. We compare our results against the coherence criteria published by Spence et al (Ultramicroscopy, 101, 149 (2004)) and show that, for iterative ab initio phase-recovery algorithms based on those typically used in CDI and in cases where the coherence properties are known we are able to relax the minimal coherence requirements by a factor of 2 both laterally and longitudinally, potentially yielding significant reduction in exposure time.

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We report on an electron-pair emission study from a Cu(111) surface excited by electron impact with different primary electron energies. We identify in the energy spectra, features that can be directly related to the underlying band structure. This, in turn, proves an important assumption in the theoretical description of the pair-emission process, namely that an effective single-particle picture for the electronic structure is an adequate description. With this observation, it is possible to identify the orbital character of the participating valence state. The relative pair-emission intensity from the surface state and 3d states is observed to vary dramatically with the primary energy. We observe particular conditions where the contribution from the Shockley surface state is strong. We propose a simplified model to explain this observation.