Materials Literature
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The flow behavior and the effect of the spinning conditions on the fiber properties and structure of the copolyesters, i.e., samples of copoly(p-hydroxybenzoate-bisphenol A terephthalate), were investigated. The experimental results indicated that the apparent viscosity was affected significantly by shear rate, melt t…
Highly fluorescent Eu-polymer complexes were synthesized through copolymerization of EuPhen(Nap)2AA with methyl methacrylate or styrene and their luminescent properties were investigated. The Eu-polymer luminophores showed intense red emission under UV excitation, and the emission intensities were much stronger than t…
Die Art des Köders bestimmt die Beute : In einem Teich mit Triethanolamin‐Liganden und Eisen(III)‐Ionen gelingt es, sechs‐ und achtgliedrige Eisencoronate 1 bzw. 2 zu fangen, je nachdem, ob man Natrium‐ oder Caesiumionen als Köder verwendet. Dies ist besonders im Zusammenhang mit der Möglichkeit kombinatorischer Ansät…
In this work, the surface treatment of poly(ethylene terephtalate) (PET) films in a low frequency (70 kHz) discharge in helium-oxygen mixtures is investigated. Optical emission spectroscopy and mass spectrometry are used to analyze the gas phase. Surface properties are analyzed via the X-ray photoelectron spectroscopy…
Angular distributions of valence photoelectrons showing effects due to higher-multipole photon interactions have been measured for the first time. Neon 2s and 2p photoemission exhibits effects beyond the dipole approximation throughout the 250 - 1200 eV photon-energy range studied. The results suggest that any photoem…
Methacrylic acid (MA) was graft polymerized onto starch using Ce4+ initiator in aqueous medium. The dependence of grafting on the reaction variables, such as monomer and initiator concentration and time and temperature, was studied in detail. Acid hydrolysis and infrared (IR) spectroscopy were used for the confirmatio…
Polyurethane elastomers based on polyols such as polycaprolactone diol of molar mass 2000 and polytetramethylene glycol of molar mass 2000; diisocyanantes such as diphenyl methane 4,4′ diisocyanate and dicyclohexyl methane 4,4′ diisocyanate; and chain extenders such as bisphenol-A, bisphenol-S,bisphenol-AF, and their…
We perform a comprehensive study of the formation of three dimensional (pyramidal) structures in a large range of conditions, including the possible evaporation of adatoms from the surface and the presence of surface defects. We compare our computer simulations to theoretical calculations of the growth and find good a…
Thin films are usually obtained by depositing atoms with a continuous flux. We show that using a chopped flux changes the growth and the morphology of the film. A simple scaling analysis predicts how the island densities change as a function of the frequency of the chopped flux in simple cases where aggregation is irr…
A helical staircase structure is observed for the layers made from chains of alternating AgI centers and pytz ligands in [Ag(pytz)(NO3)]∞ (pytz = 3,6-di-(4-pyridyl)-1,2,4,5-tetrazine). Decisive for the formation of this array—a view of the structure along the helical axis is shown on the right—is the anionic ligand NO…
The electronic structure of interfaces between lattice-mismatched semiconductor is sensitive to the strain. We compare two approaches for calculating such inhomogeneous strain -- continuum elasticity (CE, treated as a finite difference problem) and atomistic elasticity (AE). While for small strain the two methods must…
We investigate the performance of the GW approximation by comparison to exact results for small model systems. The role of the chemical potentials in Dyson's equation as well as the consequences of numerical resonance broadening are examined, and we show how a proper treatment can improve computational implementations…
Because of the subgroup - group relationship which exists between the space group of yellow InCl and that of rock salt , a Landau expansion of the free energy in invariants of the symmetry group of higher order can be performed and a mechanism for distortion arises. The special feature of this hypothetical phase trans…
The one- and two-electron ground-state energies of singly and doubly charged silicon (Si) dots modelled by a sphere covered with a silicon dioxide layer embedded in various dielectric media can be calculated as functions of the sphere size and the thickness of the oxide by extending the work of Allan et al and Babic e…
Room-temperature visible luminescence from Pr3+ ions embedded in germaniumsulfide glass hosts is reported along with edge luminescence from these hosts. The important role of energy transfer processes between the host and Pr ions is demonstrated experimentally through the dependencies of photoluminescence on excitatio…
The influence of ultraviolet (UV) illumination on piezoelectric properties is investigated in lead zirconate titanate (PZT) thin films. It is found that the poling procedure is more effective when the film is exposed to a broadband UV light in the presence of a high electric field. Piezoelectric coefficients are incre…
We have determined the inclination angle of the backbone structure of polyimide with alkyl side-chains in rubbed films. Four different polyimides with the same backbone structure but different lengths of alkyl side-chains were used in this study. The inclination angle of the backbone structure increases with the numbe…
As reported earlier, the metal hydride ${\mathrm{YH}}_{x}$ reveals spectacular switchable optical properties. In this Letter we report on another remarkable property of the hydrogen deficient ${\mathrm{YH}}_{3\ensuremath{-}\ensuremath{\delta}}$ trihydride phase. A logarithmic temperature dependence of the electrical r…
High-resolution x-ray and neutron scattering studies on powder samples of pure and Zr-doped (5 at.%) show that mesoscopic compositional inhomogeneities exist in the doped compound which are unlikely to be revealed by conventional diffraction methods. Even if the structural refinement of the doped compound gives quite…
The configuration ions and have been incorporated in strontium fluorovanadate (SVAP) crystals grown using the Czochralski technique. Such crystals provide fourfold-coordinated sites for occupancy by the and ions, which are located near the centres of their respective tetrahedrally bonded molecular ions and . The optic…