Associations de secours mutuels. Hôtels des invalides civils. Caisses de retraites. Par A. Lachèze,... [Avril 1848.]

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Journal of quantitative spectroscopy & radiative transfer

International audienceHigh harmonic amplification is shown in an optical-field ionized X-ray laser. The 4d-4p X-ray line of Kr8+ at 32.8 nm, which has a close match to the 25th harmonic of the infrared laser, was amplified up to 200 times. The energy-extraction regime was also achieved, which depended on the level of seeding. This second-generation X-ray laser is fully polarized, has low divergence and shows a high degree of coherence. The duration is also expected to be short, fulfilling the requirements for an ultra-intense tabletop X-ray laser. Conditions for higher energy output are also suggested

Second generation X-ray lasers

International audienceHigh harmonic amplification is shown in an optical-field ionized X-ray laser. The 4d–4p X-ray line of Kr^8+ at 32.8 nm, which has a close match to the 25th harmonic of the infrared laser, was amplified up to 200 times. The energy-extraction regime was also achieved, which depended on the level of seeding. This second-generation X-ray laser is fully polarized, has low divergence and shows a high degree of coherence. The duration is also expected to be short, fulfilling the requirements for an ultra-intense tabletop X-ray laser. Conditions for higher energy output are also suggested

Resistance to a social innovation: An analytic framework for problems of Fair Trade diffusion

In this study we propose conceptualizing Fair Trade as a form of social innovation. Our goal is to better understand its failure to gain general acceptance by examining consumer resistance to innovation. Research methods include observation (consumption behavior in a canteen) and face-to-face interviews. Our findings reveal that individual barriers are insufficient to explain resistance to Fair Trade. We discuss the reasons why consumers in our study showed low levels of identification with and appropriation of Fair Trade. We conclude with recommendations for facilitating the adoption of Fair Trade and social innovations.Conceptualiser le commerce équitable (CE) comme une innovation sociale permet d'éclairer ses problèmes de diffusion en étudiant la résistance à l'innovation. Une étude terrain en deux volets (quasi-expérimentation et entretiens qualitatifs) montre que lever les freins individuels ne suffit pas à vaincre la résistance aux produits issus du CE. Les failles dans le processus d'innovation sociale (appropriation, identification) sont mises au jour et discutées, ce qui débouche sur des recommandations pour faciliter la diffusion du CE et des innovations sociales

Journal of quantitative spectroscopy & radiative transfer

International audienceHigh harmonic amplification is shown in an optical-field ionized X-ray laser. The 4d-4p X-ray line of Kr8+ at 32.8 nm, which has a close match to the 25th harmonic of the infrared laser, was amplified up to 200 times. The energy-extraction regime was also achieved, which depended on the level of seeding. This second-generation X-ray laser is fully polarized, has low divergence and shows a high degree of coherence. The duration is also expected to be short, fulfilling the requirements for an ultra-intense tabletop X-ray laser. Conditions for higher energy output are also suggested

Lasers X de deuxième génération

Au LOA, nous avons réalisé la première chaîne d'amplification laser fonctionnant dans la gamme spectrale XUV. La chaîne est constituée d'une source, d'un relais d'image et d'un amplificateur. La source de génération d'harmoniques d'ordre élevé avait de bonnes qualités optiques, tandis que l'amplificateur produit intrinsèquement des impulsions de forte énergie. Afin de garder les qualités optiques de la source durant l'amplification, le laser X était pompé par ionisation par effet de champs dans un gaz neutre. La métrologie de ce laser X injecté a permis de mesurer une énergie de sortie de 0.7 $\mu$J et un haut degré de cohérence et de polarisation. La durée de l'impulsion a été estimée à 500 fs. On peut espérer atteindre un éclairement de 1.5$\times$10$^{16}$ Wcm$^{-2}$ en focalisant le faisceau

A high-intensity highly coherent soft X-ray femtosecond laser seeded by a high harmonic beam

International audienceSynchrotrons have for decades provided invaluable sources of soft X-rays, the application of which has led to significant progress in many areas of science and technology. But future applications of soft X-rays—in structural biology, for example—anticipate the need for pulses with much shorter duration (femtoseconds) and much higher energy (millijoules) than those delivered by synchrotrons. Soft X-ray free-electron lasers1 should fulfil these requirements but will be limited in number; the pressure on beamtime is therefore likely to be considerable. Laser-driven soft X-ray sources offer a comparatively inexpensive and widely available alternative, but have encountered practical bottlenecks in the quest for high intensities. Here we establish and characterize a soft X-ray laser chain that shows how these bottlenecks can in principle be overcome. By combining the high optical quality available from high-harmonic laser sources (as a seed beam) with a highly energetic soft X-ray laser plasma amplifier, we produce a tabletop soft X-ray femtosecond laser operating at 10 Hz and exhibiting full saturation, high energy, high coherence and full polarization. This technique should be readily applicable on all existing laser-driven soft X-ray facilities