Thermal degradation of vinyl alcohol/vinyl acetate copolymers. III. Study of the reaction products

The thermal decomposition of vinyl alcohol/vinyl acetate copolymers have been studied at p = 10⁻²–10⁻⁴ Torr and T = 0–600°C. The decomposition products (solids, liquids, and gases) have been characterized by infrared (IR) and ultraviolet (UV) spectroscopy, gas chromatography, vapor pressure osmometry, and elemental analysis. It has been ascertained on the basis of the obtained data that the decomposition mechanism of the vinyl alcohol/vinyl acetate copolymers depends on the chemical composition and sequence distribution of comonomers.     

Sur la pseudo-compatibilite des systemes polymere-polymere

Compatibility in polymeric systems is discussed. By considering the dimensions of the macromolecules and their restricted mobility, in addition to incompatible and compatible polymeric systems, there are pseudo-compatible mixtures which have great practical significance; because of negligible rate of phase separation, these systems show appreciable “apparent” compatibility. The pseudo-compatible polymeric mixtures are very fine dispersions, stabalized by different forces of interaction, the stability being higher the greater the degree of dispersion.     

Surface relaxation influenced by surface states

A detailed theoretical investigation of the relaxation of the simple metal surface Al(100) is presented. We show the influence of electronic surface states in this context. The sign and magnitude of the relaxation of the topmost atomic layers is mainly determined by the rearrangements of the surface state charge. The degree of surface relaxation convergence, with respect to the number of slab layers, is determined by the location of the surface state band relative to bulk bands.     

On the design of low-thrust transfers through L1 for the ESMO mission

The following paper summarises the mission analysis studies performed for the phase A of the solar electric propulsion option of the European Student Moon Orbiter (ESMO) mission. ESMO is scheduled to be launched in 2011, as an auxiliary payload on board an Ariane 5. Hence the lack of influence on the launch date. Two methods were devised to assess efficiently wide launch windows for the Earth-Moon transfer, they are presented below. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Interface charge transfer process in ZnO:Mn/ZnS nanocomposites

Journal of Nanoparticle Research - TiO2 photocatalysts co-doped with F and Fe were synthesized by a sol–gel method. Synergistic effects of F and Fe in the co-doped TiO2 were verified by NH3...     

Ball milling synthesis and stability under pressure in nanostructured HITPERM alloys

The main aim of the present work is to study the synthesis and stability of soft-magnetic nanostructured materials under high pressure-high temperature conditions. HITPERM alloy powders were prepared by high-energy ball-milling. The as-milled alloys consist of an iron-based nanocrystalline solid solution. The evolution of crystallinity and grain-size during the ball-milling process and investigations under external pressure up to 3 GPa for temperatures up to 1200 °C were evaluated using synchrotron radiation X-ray diffraction.