Master Equation for the Motion of a Polarizable Particle in a Multimode Cavity

We derive a master equation for the motion of a polarizable particle weakly interacting with one or several strongly pumped cavity modes. We focus here on massive particles with complex internal structure such as large molecules and clusters, for which we assume a linear scalar polarizability mediating the particle-light interaction. The predicted friction and diffusion coefficients are in good agreement with former semiclassical calculations for atoms and small molecules in weakly pumped cavities, while the current rigorous quantum treatment and numerical assessment sheds a light on the feasibility of experiments that aim at optically manipulating beams of massive molecules with multimode cavities.Comment: 30 pages, 5 figure

Growth and fructification of a Norway spruce (Picea abies L. Karst) forest ecosystem under changed nutrient and water input

In the mountainous region of a low mountain range (Solling mountains) an ecosystem manipulation experiment with roof constructions underneath the canopy of a 60-year old Norway spruce stand is run since 1991. The responses to artificially prepared, “pre-industrial" through fall and to extended summer droughts with intensive rewetting are investigated in two parallel roof experiments and evaluated against a roof control and an ambient control plot. After long terms of drought distinct reactions of the trees were visible in growth. The reactions of height-increment were more distinct than the effects on diameter-increment. Furthermore, the trees of the dominating social classes (Kraft I and II) reacted more on low water-supply than the dominated trees. So it is probable that a long lasting stress by drought effects changes the stand structure, too: the vertical structure of a stand would get more homogeneous and the diversity in the stand structure would decrease. Reduced input of sulphur and nitrogen did not show any distinct growth reactions within the 9-year observation period.Croissance et fructification d'un écosystème forestier d'épicéa commun soumis à un apport variable d'eau et de nutriments. Dans la partie haute d'une région montagneuse de moyenne altitude (Solling), on procède depuis 1991 à une expérience de manipulation d'un écosystème forestier à l'aide de constructions de toits en dessous des couronnes d'un peuplement d'épicéa commun âgé de 60 ans. Dans le cadre de deux expériences parallèles (de toit), on étudie les réactions à des précipitations “ préindustrielles " créées artificiellement et à une sécheresse estivale prolongée, suivie d'une réhumidification intensive, en évaluant et en comparant ces résultats à une placette témoin. Après de longues périodes de sécheresse, on a pu observer des réactions différentes des arbres sur le plan de la croissance. Les réactions au niveau de la croissance en hauteur s'avèrent différentes des effets sur l'accroissement en diamètre. En outre, les arbres dominants (Kraft I et II) témoignent d'une réaction plus prononcée à un faible apport d'eau que les arbres dominés. Ainsi, il est probable qu'un stress de longue durée par l'effet de la sécheresse modifie également la structure du peuplement : la structure verticale d'un peuplement devient alors plus homogène, tandis que la diversité du peuplement diminue. Les effets d'un apport réduit de soufre et d'azote n'ont pas révélé de réactions différentes sur le plan de la croissance au cours de la période d'observation de 9 ans

Few-Layer Graphene Shells and Nonmagnetic Encapsulates: A Versatile and Nontoxic Carbon Nanomaterial

In this work a simple and scalable approach to coat nonmagnetic nanoparticles with few-layer graphene is presented. In addition, the easy processing of such nanoparticles to remove their core, leaving only the 3D graphene nanoshell, is demonstrated. The samples are comprehensively characterized, as are their versatility in terms of functionalization and as a material for electrochemical storage. Indeed, these 3D graphene nanostructures are easily functionalized much as is found with carbon nanotubes and planar graphene. Electrochemical investigations indicate these nanostructures are promising for stable long-life battery applications. Finally, initial toxicological investigations suggest no acute health risk from these 3D graphene nanostructures. © 2013 American Chemical Society.123241sciescopu