Materials Literature
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Abstract The molecular weight of polyester polyol plays an important role in controlling mechanical and dynamic mechanical properties of polyurethanes. Two systems are studied for evaluation of these properties. Since the properties of polyurethanes are derived from the properties of various constituents involved in t…
Abstract In‐line monitoring of monomer conversion is studied using a low‐frequency dielectric sensor during solution polymerization of methyl methacrylate in a laboratory‐scale batch reactor. It has been found that the induction period due to the presence of an inhibitor can be determined by the dielectric sensor to d…
Abstract Fracture behavior of polypropylene (PP)/ethylene–propylene–rubber (EPR) blends containing small crystal in elastomeric phase was investigated. Various ethylene‐α‐olefin co‐polymers (ECP) were used as crystal components and put into the elastomer phase of the blends. The crystallite size was controlled by chan…
Abstract A calorimetric study for estimating crosslinking densities of polydimethylsiloxane (PDMS) networks is presented. It involves the experimental determination of the heat capacities of the polymer with ( C ) and without ( C ) crosslinking. The theoretical basis of the method is described as well as the procedure…
Abstract The aim of this work is to extend an isotropic elastoplastic damage concept for ductile materials within a generalized micropolar continuum framework. The underlying motivation is on the one hand to model softening behaviour by damage evolution and on the other hand to regularize the impending loss of ellipti…
In this paper the specific properties of free clusters and the formation of new cluster-assembled materials using the low energy cluster beam deposition (LECBD) technique are discussed. Recent results obtained for free clusters are summarized with special attention to new observed structures. As for the specific struc…
The structure of a common batch of amorphous hydrogenated carbon samples (a-C:H) has been studied in detail using time of flight neutron diffraction, inelastic neutron scattering, NMR and molecular dynamics (MD) simulation. Supplementary work has included differential scanning calorimetry (DSC), infrared (IR) spectros…
Using a genuine organic ferromagnetic radical crystal (${\mathrm{C}}_{10}$${\mathrm{H}}_{10}$${\mathrm{N}}_{4}$SCl) which was synthesized recently, we experimentally examined the results of quantum statistics for a one-dimensional Heisenberg ferromagnet with spin $S=\frac{1}{2}$. The characteristic thermodynamical pro…
Visible luminescence from silicon nanostructures fabricated by using conventional lithographic and reactive ion etching techniques and final thinning by high temperature thermal oxidation was obtained at room temperature under 488 nm argon laser excitation. Highly anisotropic vertical silicon pillars with aspect ratio…
The recently discovered giant magneto-impedance (GMI) effect has been measured as a function of circular driving-field frequency and applied tensile stress on two near-zero-magnetostriction amorphous wires. The effect of different orientations of the induced magnetoelastic anisotropy has been verified, for the first t…
We have measured dark DC conductivity and time-of-flight (TOF) of carriers in self-supporting porous silicon films in the temperature range 298–480 K. The dark I-V curves show superlinear behavior with activation energies of 0.38–0.67 eV. The TOF measurements allowed us to evaluate the drift-length of non-equilibrium…
We report the first evidence of an excitonic polaron and exciton-phonon complexes in nanosize semiconductor crystals. These are observed in CuCl nanocrystal excitonic luminescence spectra under resonant size-selective excitation. The theory of exciton coupling with spherical phonons through the Fr\"ohlich and deformat…
Highly crystallized polycrystalline film of single-phase CaWO4 has been prepared on a tungsten substrate at room temperature in an alkaline solution containing calcium ions by an electrochemical method with the current density of 1 mA/cm2. This film showed blue emission (456 nm wavelength) with excitation light (254 n…
A molecular dynamics simulation of the alpha - and beta -phases of cristobalite has been performed. The simulated beta -phase was found to be much more disordered than the alpha -phase, in agreement with evidence from many experimental techniques. The nature of the disorder was found to be dynamic, in agreement with r…
First-principles molecular dynamics simulations having a duration of 8 ps have been used to study the static, dynamic and electronic properties of l-Ga at the temperatures 702 K and 982 K. The simulations use the density-functional pseudopotential method and the system is maintained on the Born-Oppenheimer surface by…
The magnetocrystalline anisotropy energy $E_{anis}$ for a monolayer of Fe and Ni is determined using a fully convergent tight-binding calculation including $s$-$d$ hybridization. The spin-orbit interaction $λ_{so}$ is treated non-perturbatively. Remarkably, we find $E_{anis}\proptoλ_{so}^2$ and important contributions…
We measured the time dependencies of the dielectric permittivity of a single crystal lead magnoniobate in the zero-field--cooled regime. The logarithmic decay of the dielectric response was observed in the glassy phase. We measured the time $\ensuremath{\tau}$ from the moment of the field application for the phase tra…
We present nonlocal density-functional calculations for a model of the [Fe4S4]3+ cluster found in high potential iron proteins, which consists formally of a ferric pair Fe 3+Fe3+ and a mixed-valence pair Fe 2.5+Fe2.5+. Three Spin Hamiltonian parameters, J (the interlayer Heisenberg interaction), B (a resonance deloca…
We present the results of ab initio calculations on the first-, second-, and third-order molecular polarizabilities of urea. An efficacious general finite field perturbation approach, previously applied in the case of paranitroaniline, is extended to the evaluation of axial and nonaxial components of the nonlinear res…
Mandelate racemase and muconate lactonizing enzyme are structurally homologous but catalyze different reactions, each initiated by proton abstraction from carbon. The structural similarity to mandelate racemase of a previously unidentified gene product was used to deduce its function as a galactonate dehydratase. In t…