Abstract The fluorination of a diversity of functionalized aryl iodides is readily achieved by silver fluoride in the presence of a cationic copper complex.The reaction is proposed to proceed by C—F reductive elimination from an in situ generated aryl copper(III) fluoride.
We overview an approach to modeling and rendering architectural scenes from a sparse set of photographs. The approach is designed to require no special hardware and to produce real-time renderings on standard graphics hardware. The modeling method is an interactive photogrammetric modeling tool for recovering geometric models of architectural scenes from photographs. The tool is practical as an interactive method because it solves directly for architectural dimensions rather than for a multitude of vertex coordinates or depth measurements. The technique also determines the camera positions of the photographs, allowing the photographs to be taken from arbitrary unrecorded locations. The rendering method creates novel views of the scene based on the recovered model and the original photographs. A view-dependent texture mapping method allows all available image information to be used to produce the most photorealistic renderings. We focus on a number of results and applications of the method.
In this work we deal with slow–fast autonomous dynamical systems. We initially define them as being modeled by systems of differential equations having a small parameter multiplying one of their velocity components. In order to analyze their solutions, some being chaotic, we have proposed a mathematical analytic method based on an iterative approach [Rossetto et al., 1998]. Under some conditions, this method allows us to give an analytic equation of the slow manifold. This equation is obtained by considering that the slow manifold is locally defined by a plane orthogonal to the tangent system's left fast eigenvector. In this paper, we give another method to compute the slow manifold equation by using the tangent system's slow eigenvectors. This method allows us to give a geometrical characterization of the attractor and a global qualitative description of its dynamics. The method used to compute the equation of the slow manifold has been extended to systems having a real and negative eigenvalue in a large domain of the phase space, as it is the case with the Lorenz system. Indeed, we give the Lorenz slow manifold equation and this allows us to make a qualitative study comparing this model and Chua's model. Finally, we apply our results to derive the slow manifold equations of a nonlinear optical slow–fast system, namely, the optical parametric oscillator model.
Abstract The first Ir‐catalyzed enantioselective allylation of trisubstituted allylic electrophiles has been developed. Through modification of the leaving group of allylic electrophiles, we found that trisubstituted allylic phosphates are suitable electrophiles for asymmetric allylation. The reaction of allylic phosphates with enol silanes derived from dioxinones gave allylated products in good yields with high enantioselectivities.
Abstract The light environment during plant growth determines the structural and functional properties of higher plant chloroplasts, thus revealing a dynamically regulated developmental system. Pisum sativum plants growing under intermittent illumination showed chloroplasts with fully functional photosystem (PS) II and PSI reaction centers that lacked the peripheral chlorophyll (Chi) a/b and Chl a light‐harvesting complexes (LHC), respectively. The results suggest a light flux differential threshold regulation in the biosynthesis of the photosystem core and peripheral antenna complexes. Sun‐adapted species and plants growing under far‐red‐depleted illumination showed grana stacks composed of few (3–5) thylakoids connected with long intergrana (stroma) thylakoids. They had a PSII/PSI reaction center ratio in the range 1.3–1.9. Shade‐adapted species and plants growing under far‐red‐enrichcd illumination showed large grana stacks composed of several thylakoids, often extending across the entire chloroplast body, and short intergrana stroma thylakoids. They had a higher PSII/PSI reaction center ratio, in the range of 2.2–4.0. Thus, the relative extent of grana and stroma thylakoid formation corresponds with the relative amounts of PSII and PSI in the chloroplast, respectively. The structural and functional adaptation of the photosynthetic membrane system in response to the quality of illumination involves mainly a control on the rate of PSII and PSI complex biosynthesis.
