Remarque sur ma note “La convergence absolue des séries de Fourier”

Sans résumé     

Fredholm Properties of the Difference of Orthogonal Projections in a Hilbert Space

Buckholtz (Proc. Amer. Math. Soc. 128 (2000), 1415–1418) gave necessary and sufficient conditions for the invertibility of the difference of two orthogonal projections in a Hilbert space. We generalize this result by investigating when the difference of such projections is a Fredholm operator, and give an explicit formula for its Fredholm inverse.     

Stereochemistry of cercosporin

The absolute configuration of the asymmetric carbons and the axial chirality of the natural mold metabolite cercosporin (from $\text{Cercospora sp}$.) have been established on the basis of X-ray analysis and chemical reactions. The results confirm the inherent dissymmetry of the perylenequinone ring, the twisting of which gives rise to the diastereoisomer isocercosporin. The energy barrier for the conversion of cercosporin into isocercosporin has been evaluated.     

The influence of kinetics on the direct titration curves of natural water systems — theoretical considerations

The effect of rate of complex formation is calculated on the titration curves of natural waters with traces of metals. The effect can be distinguished from multiple complex formation.     

Self-consistent nonlocal potentials near planar surfaces

A new derivation of the self-consistent dynamically screened nonlocal Coulomb potential near a planar surface is presented, based on the integral equation approach. The exact solution is obtained without restrictions on the dynamical response of the solid (e.g. RPA in metals), the type of surface potential or electronic density profile, and without additional matching or boundary conditions. This makes the present approach particularly useful e.g. in the general discussion of model-independent screening phenomena at metal surfaces. The application to the calculation of matrix elements for electron and ion excitation of collective modes and electron-hole pairs is formulated, and the connection with the previous results discussed.     

The breakdown of scaling due to the possible structure of nucleonic constituents

Aside from relativistic quark model representations which correspond to the picture of point-like quarks, the current algebra also allows representations which can be interpreted in terms of quarks with structure. We speculate about the possibility that the experimentally observed small deviations from scaling for higher values of q² point out the extended nature of nucleon constituents.     

Dünnschicht-chromatographische Trennung der Phenole auf Stärke

By thin-layer chromatography on rize starch mixtures of phenol, pyrocatechol, resoroinol, hydroquinone and pyrogallol as well as chloro- and nitroderivatives of phenol were separated. By Martin's theoretical postulates for partition chromatography the R _M -values and group constants were calculated.