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The local and average texture of thick polycrystalline CdTe films is determined before, upon, and after the coalescence of the initially isolated islands, using electron backscattered diffraction and x-ray powder diffraction. The coalescence and postcoalescence processes lead to a preferential texturation, initially along the <531> and <100> crystallographic directions and then along the <110> preferred orientation. The selection of grain orientation during the film growth is found to be driven by strain energy minimization. A model for the microyield stress is developed when plasticity is confined to each elemental grain and accounts for the <531> and <100> preferred orientations. On the contrary, when plastic deformation can propagate from one grain to its neighbors, the Hall–Petch model applies and leads to the <110> preferred orientation. Furthermore, at the end of growth, the stronger <111> preferred orientation is observed and arises because of kinetic limitations. [ABSTRACT FROM AUTHOR]

By combining simultaneously in situ x-ray diffraction and curvature measurements, the stress evolution during silicide formation in thin Pd films deposited on Si substrates has been reliably investigated. The in-plane strain in the silicide is compressive. The combination method also permits the determination of the elastic constants and thermal expansion coefficient of Pd[sub 2]Si ([001] fiber texture): E[sub sil] = 86 ± 8 GPa, v[sub sil] = 0.34 ± 0.05, and α[sub sil] = 13.2 × 10[sup -6] K[sup -1]. It is shown that during growth the average compressive stress increases progressively up to a maximum temperature-dependent value (-1.5 GPa at 220 °C) and then vanishes for long annealing. This behavior is in reasonable agreement with the predictions of a model by Zhang and d'Heurle [S. L. Zhang and F. M. d'Heurle, Thin Solid Films 213, 34 (1992)]. A strain gradient in the growing silicide layer, which is predicted by the model, has been shown. [ABSTRACT FROM AUTHOR]

Presents information on a study which analyzed the elastic strains in gold/nickel multilayer films using x-ray diffraction. Stress determination using x-ray diffraction; Results and discussion; Conclusions.

Byline: P. Gergaud, P. Goudeau, O. Sicardy, N. Tamura, O. Thomas Micro- and nano-structured materials often exhibit high level of residual stresses which may affect the reliability of electronic devices. Stress control is, therefore, essential for improving device lifetime. X-ray diffraction is one of the most widely used techniques for stress analysis. It is essentially non destructive and allows for the study of both the microstructural and elastic properties of all the diffracting phases in complex materials. With the advent of third generation synchrotrons and the development of new X-ray optics and detectors as well as enhanced data analysis capabilities, measurements of specific stress features such as local stresses, stress gradients and stress heterogeneities are now within reach. This paper reviews the state of the art in that field illustrated with a few examples.

The experiments of stress arising during solid-state reaction between a Pd thin film and a Si (001) substrate are put forth. The experiments give reliable information of silicide growth kinetics, elastic constants and the stress buildup in the silicide.

Background and Aims Nucleotide Oligomerisation Domain 2 [ NOD2 ] is a key gene of innate immunity which participates in the host defence against pathogens. Several loss-of-function NOD2 mutations are associated with Crohn's disease [CD]. Their high frequencies in populations of European ancestry suggest a model of balancing selection. Because NOD2 deficiency has been associated with a resistance to Yersinia pseudotuberculosis in mice, we hypothesised that NOD2 mutations have been selected during past plague outbreaks due to the closely related bacterium Yersinia pestis. Methods Contemporary frequencies of the main CD-associated NOD2 mutations [R702W, G908R, and 1007fs], measured in healthy people from European and Mediterranean countries, were collected from 60 studies via a PubMed search. Plague exposure was calculated from a dataset providing outbreaks from 1346 to 1860 in Europe and the Mediterranean Bassin. A plague index was built to capture the intensity of plague exposure in the studied geographical areas. Results NOD2 mutation frequencies were associated with the past exposure to plague. Statistical significance was obtained for the most frequent mutation [R702W, p = 0.03] and for the pooled three mutations [ p = 0.023]. The association remained significant when putative demographic biases were considered. Conclusions This result argues for a selection of CD-associated NOD2 mutations by plague outbreaks and further questioned the role of exposure to enteropathogenic Yersinia species in CD. [ABSTRACT FROM AUTHOR]