Materials Literature
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The present paper deals with some mathematical aspects of generalized time-dependent Ginzburg–Landau theories for the numerical simulation of mesoscale phase separation kinetics of copolymer melts. We shortly discuss the underlying theory and introduce an expansion of the external potential, to be used in the dynamics…
We develop here a highly efficient variant of the Monte Carlo method for direct evaluation of the partition function, free energy, and other configurational dependent physical properties for long polymer chains. This method (CC–BB) combines continuous configurational biased sampling with Boltzmann factor biased enrich…
We use a recently developed density-functional perturbation theory, which has been applied successfully to predict phase diagrams of systems of attractive particles, to describe the phase diagram of particles interacting via repulsive potentials. We consider potentials composed of a hard-sphere core plus a repulsive t…
Using the bond-fluctuation-algorithm we perform dynamic Monte Carlo simulations on dense symmetric copolymer melts. We cover structures from homogeneous melts to strongly separated regimes. We confirm the scaling laws found in previous simulations for the static properties of the chains and extend these laws into the…
The phase diagram of fluids of hard biaxial ellipsoids with c/a=10 and b/a∈{1,10}, where a, b, and c are the semi-axes, has been studied using computer simulation. Four homogeneous phases are in evidence: isotropic (I), nematic (N+), discotic (N−) and biaxial (B). First-order isotropic-nematic and isotropic-discotic c…
We critically discuss relaxation experiments in magnetic systems that can be characterized in terms of an energy barrier distribution, showing that proper normalization of the relaxation data is needed whenever curves corresponding to different temperatures are to be compared. We show how these normalization factors c…
An experimental study of the origin and hitherto unexplored structure of the pressure - tension cycles accompanying the cavitation of liquids under dynamic stressing by tension is presented. The results of this study are relevant to certain problems in engineering and medicine, and the potential for application of the…
Although the low-threshold emission from polycrystalline diamond heavily doped with nitrogen has been proposed in our previous report, this is the first report on a practical diamond cold cathode, having pyramidal-shape array structure, promising for battery-driven flat panel displays. We have used urea [(NH3)2CO] as…
Synthesis of the perovskite solid solution that forms between metallic SrRuO3 and insulating SrSnO3 is reported. This material is proposed as a conducting thin-film electrode/epitaxial-substrate material. While the bulk solid solution could not be formed, thin films of single-phase SrRu0.5Sn0.5O3 were grown on (001) K…
Thermoluminescence glow peaks are calculated numerically for a one-trap-one-recombination-centre model using a generalized approach. Except in extreme cases the peaks are seen to change in position and shape with a change in dose. These glow peaks are fitted to the general-order kinetics model and the values of the ki…
We report room-temperature cathodoluminescence and photoluminescence spectra originating from ZnS overcoated CdSe nanocrystals, 33 and 42 Å in diameter, embedded in a ZnS matrix. The thin-film quantum dot composites were synthesized by electrospray organometallic chemical vapor deposition. Cathodoluminescence and phot…
The experimental, as well as theoretical, values for the frequency-dependent hyperpolarizability of ${\mathrm{C}}_{60}$ differ by orders of magnitude. We present the first density functional calculation of a molecular frequency-dependent hyperpolarizability. Our implementation is very economical, enabling the treatmen…
The specific heat of the perovskite manganite ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3+\ensuremath{\delta}}$ was measured in the doping regime $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.0$ to 0.3 where at low temperatures the material changes from a layered antiferromagnetic insu…
The bilayer manganite ${\mathrm{La}}_{1.2}{\mathrm{Sr}}_{1.8}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ exhibits a transition between nearly insulating paramagnetic and metallic ferromagnetic states at ${T}_{C}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}126\mathrm{K}$. We use magnetic neutron scattering to show that th…
The electronic structure of amorphous silicon nanoclusters is calculated within the empirical tight-binding approximation. The electronic states are classified into three groups: extended and weakly and strongly localized. The last category practically disappears in hydrogenated amorphous silicon clusters for which th…
The oxidation of single crystal gallium nitride in dry air has been investigated. X-ray photoelectron spectroscopy (XPS) revealed minimal oxide growth at 450 and 750 °C for up to 25 h. However, at 900 °C the growth of an oxide approximately 5000 Å thick was observed after 25 h. This oxide was determined to be the mono…
There are two current ways to evaluate the adiabatic corrections to a potential energy hypersurface: firstly a rigorous way in which one starts with the separation of the centre-of-mass motion and where one gets rather complicated expressions in terms of relative coordinates in a molecule-fixed frame, and secondly a p…
This is the second part of a study of chemical structure-physical property-performance relationships among several fluoropolymers and liquid penetrants, focusing on their permeation behavior. That behavior was consistent with the chemical and physical characteristics of the polymers, in that it depended on thermodynam…
In exzellenter Ausbeute ist das Carbaporphyrin 1 durch Anwendung der „3 + 1”︁‐Strategie zugänglich. Dabei wird Inden‐1,3‐dicarbaldehyd in Gegenwart von 5proz. Trifluoressigsäure in Dichlormethan mit einem Tripyrran umgesetzt. Das verwandte Formylcarbaporphyrin 2 wurde auf ähnlichem Wege hergestellt. Entgegen früheren…
This is the first part of a study of chemical structure-physical property-performance relationships among several fluoropolymers and liquid penetrants, focusing on their diffusivities and solubilities. Transient sorption experiments conducted with perfluoroalkoxy, fluorinated ethylene propylene, and ethylene tetrafluo…