Materials Literature
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Alumina trihydrate is an effective and widely used fire retardant and smoke suppressant, with several other incidental advantages, but it usually lowers the mechanical strength of thermosetting resins and laminates. This paper reports the extent of the reduction in the impact damage tolerance of glass-epoxy woven rovi…
This paper describes recent results of research on organic materials, especially organic photopolymers for opto-electronic devices, which are contributing to the realization of the “Multimedia World” in the 21st century. For this purpose two photoactive polymers were developed for Gbit-scale dynamic random access memo…
The Crystallographic Information File (CIF) uses the self-defining STAR file structure. This requires the creation of a dictionary of data names and definitions. A basic dictionary of terms needed to describe the crystal structures of small molecules was approved in 1991 and is currently used for the submission of pap…
The addition of metallic fillers is recognized to impart improvement of acoustic properties to polyurethane-based materials used for marine applications. The system under consideration was obtained by the reaction of a triisocyanateterminated prepolymer with 1,4-butanediol, in the presence of various concentrations of…
Conventional rigid polyisocyanurate (PUIR) foams blown with HCFC-141b often suffer from poorer compressive strengths, dimensional stability and inferior flammability properties when compared to foams blown with CFC-11. It is often hypothesized that these properties can be improved by increasing the isocyanurate (or "t…
Abstract Mineral fillers have been used very often in the past for improving elastic modulus and temperature resistance of polyolefines, also to the detriment of impact resistance. Very recently it has been pointed out that good fracture toughness can be achieved if an appropriate mechanism is stimulated and a good bo…
Abstract The miscibility of isotactic polypropylene (PP) in blends with (a) polystyrene‐ block ‐poly(ethylene‐ stat ‐butylene)‐ block ‐polystyrene (SEBS) and processing oil, (b) poly(ethylene‐ co ‐propylene) (EPM), and (c) EPM and processing oil, has been studied using the method of melting‐point depression. Near equi…
The popular assumption that all salts are totally ionized in aqueous solution is false. Moreover, it is approximated only by alkali metal salts and by salts of alkaline earth metals with high atomic numbers.
Diffusion of the aroma compounds p-cymene and acetophenone into three different packaging films was studied at 500 MPa for kinetic measurement, and in the range of 0.1–450 MPa for measurement of the diffusion rate as a function of pressure. Absorption of aroma compounds was lower in pressurized than in nonpressurized…
The morphology of fullerene networks can be widely extended by introducing heptagonal or octagonal rings, which produce a Gaussian negative curvature. Their presence makes it possible to form donut-, coil- and sponge-shaped networks of carbon atoms. We discuss the geometry of the polymorphous forms based on the net di…
Wholly aromatic polybenzimidazoles were synthesized from aromatic tetraamines and difunctional aromatic acids and characterized as new thermally stable polymers. The melt polycondensation of aromatic tetraamines and the diphenyl esters of aromatic dicarboxylic acids was developed as a general procedure of wide applica…
The magnetoelastic properties of steel wires are used for measuring a mechanical load in tension. A microcomputer-controlled measuring instrument was designed. The dependence of magnetic behaviour on a previous state is eliminated by the suggested method of commutated measurement of amplitude permeability from saturat…
We examine the behaviour of nematic 4,4′-n-octylcyanobiphenyl (8CB) subjected to steady torsional shear flow at a temperature where this nematic is ‘tumbling’, i.e. the ratio α3/α2 of Leslie viscosities is negative. If the disc rotation speed is gradually increased from zero ( < 10−6 rad s−2), the director eventually…
A shape memory alloy rod, if it is pre-twisted to create stress induced martensitic transformation, will exhibit a torsional shape memory effect, namely, some of the pre-twist will be recovered once the SMA rod is heated above its austenitic start temperature. If the pre- twisted SMA rod is constrained, a large recove…
Relaxation phenomena in disordered systems are often described by stretched exponentials; such behavior has traditionally been explained by invoking statistical distributions. In hydrogenated amorphous silicon, the relaxation has been associated with dispersive diffusion of hydrogen, related to a distribution of energ…
data along with the appropriate crystallographic, physical and experimental information. This paper reviews the development and growth of the PDF and discusses the role of the ICDD in the maintenance and dissemination of the file.
The Si 2 N 2 O(s) compound is vaporized in a multiple Knudsen‐cell connected to a mass spectrometer. Comparison of SiO(g) and N 2 (g) pressures between different samples in the Si‐N‐O system, as triphasic or diphasic mixtures from Si(s), Si 3 N 4 (s), and Si 2 N 2 O(s), allows the determination of the SiO(g) evaporati…
A model for calculating the electron inelastic mean free path and stopping power in insulators in the 50 eV–10 keV energy range is presented. Both valence and core electron contributions have been considered. The valence part has been estimated following the dielectric theory modified to include the energy gap; the co…
Abstract A model was developed in order to calculate the texture evolution of a growing film with large atomic diffusion on the surface. The tendency for lowest surface energy was taken as the driving force for the evolution. The orientation dependent surface energy y was approximated by a function with a sharp minimu…
We report the first direct measurements of disclination density during shear flow of a nematic liquid crystal. Samples of 4,4′-n-pentylcyanobiphenyl, or 5CB, are initially aligned in the homeotropic configuration within a torsional shear cell using surface treatment with lecithin. For low shearing rates, the director…