Some results on polarized partion relations of higher dimension

Several types of polarized partition relations are considered. In particular we deal with partitions defined on cartesian products of more than two factors. MSC: 03E05.     

In-situ study of sol–gel processing by time-resolved infrared spectroscopy

Sol–gel processing of thin films involves time dependent phenomena which are basically driven by solvent evaporation. An example is evaporation induced self-assembly that is used to prepare mesoporous ordered films through self-organization of templating micelles. The possibility to follow in situ as a function of time the evolution of the system can give a better knowledge of the process and the physics and chemistry beneath. Time-resolved infrared techniques have been applied to different sol–gel systems to study time-dependent phenomena, in particular rapid scan time resolved infrared spectroscopy has been used to monitor in situ the process and as a tool to design the sol–gel synthesis.     

On nonstationary flow through porous media

Summary Saturated-unsaturated flow of an incompressible fluid through a porous medium is considered in the case of time-dependent water levels. This corresponds to coupling the mass conservation law with a continuous constitutive condition between water content and pressure. An existence result for the corresponding weak formulation is proved. Finally we study the limit as the constitutive relation degenerates into a maximal monotone graph.This work was supported by the Deutsche Forschungsgemeinschaft through Sonderforschungsbereich 123 (Heidelberg).On leave from: Istituto di Analisi Numerica del C.N.R., Corso C. Alberto 5 - I 27100 Pavia (Italy).     

Liquid crystal behaviour of linear copolymers—II

A family of linear copolymers, characterized by the presence along the polymer chain of variable amounts of two atomic groups of different mesogenic potentiality, has been studied by differential scanning calorimetry and X-ray diffraction methods. The range of composition that allows enantiotropic mesophasic behaviour is defined for four homologous sets of copolymers. The experimental phase diagram gives, by extrapolation, indications about the potential mesophasic properties of that extreme composition (corresponding to a homopolymer) that shows no direct mesophasic properties.     

QUENCHING OF ENZYME GENERATED TRIPLET ACETONE BY 2-METHYL-1,4-NAPHTOQUINONE

Abstract 2-Methyl-1,4-naphtoquinone (vitamin K₃) quenches the phosphorescence from enzyme-generated triplet acetone. Concomitantly the vitamin undergoes a photochemical-like alteration as the result of transfer of the electronic energy ( k _ET– 1 ± 10⁵ M^-1). This transfer appears to be of the long-range type.     

Adsorption of silanes bearing nitrogenated Lewis bases on SiO2/Si (100) model surfaces

The present paper describes the one-pot procedure for the formation of self-assembled thin films of two silanes on the model oxidized silicon wafer, SiO2/Si. SiO2/Si is a model system for other surfaces, such as glass, quartz, aerosol, and silica gel. MALDI-TOF MS with and without a matrix, XPS, and AFM have confirmed the formation of self-assembled thin films of both 3-imidazolylpropyltrimethoxysilane (3-IPTS) and 4-(N-propyltriethoxysilane-imino)pyridine (4-PTSIP) on the SiO2/Si surface after 30 min. Longer adsorption times lead to the deposition of nonreacted 3-IPTS precursors and the formation of agglomerates on the 3-IPTS monolayer. The formation of 4-PTSIP self-assembled layers on SiO2/Si is also demonstrated. The present results for the flat SiO2/Si surface can lead to a better understanding of the formation of a stationary phase for affinity chromatography as well as transition-metal-supported catalysts on silica and their relationship with surface roughness and ordering. The 3-IPTS and 4-PTSIP modified SiO2/Si wafers can also be envisaged as possible built-on-silicon thin-layer chromatography (TLC) extraction devices for metal determination or N-heterocycle analytes, such as histidine and histamine, with "on-spot" MALDI-TOF MS detection.     

Quasilinear first-order PDEs with hysteresis

This paper deals with the Cauchy problem for a quasilinear first-order equation that includes a possibly discontinuous hysteresis operatorF:

     

Backward inducing and exponential decay of correlations for partially hyperbolic attractors

We study partially hyperbolic attractors ofC ² diffeomorphisms on a compact manifold. For a robust (non-empty interior) class of such diffeomorphisms, we construct Sinai-Ruelle-Bowen measures, for which we prove exponential decay of correlations and the central limit theorem, in the space of Hölder continuous functions. The techniques we develop (backward inducing, redundancy elimination algorithm) should be useful in the study of the stochastic properties of much more general non-uniformly hyperbolic systems.