Materials Literature
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The light-induced reorientation of nematic liquid crystals is discussed with special emphasis on the effect of dye-dopants. A molecular model is presented which accounts for the large increase of the optical torque, observed in absorbing nematics. An analogous process is described for dye-doped isotropic liquids and t…
We investigate the formation of a two-dimensional quasicrystal in a monodisperse system, using molecular dynamics simulations of hard-sphere particles interacting via a two-dimensional square-well potential. We find that more than one stable crystalline phase can form for certain values of the square-well parameters.…
At the macroscopic scale two different phenomena illustrate the couplings between the elastic and magnetic behaviours of ferromagnetic materials: first, magnetisation induces a deformation mechanism called magnetostriction, and, second stresses have an effect on the magnetic behaviour. The complexity of the non-linear…
A detailed survey is given of the models devised to describe the kinetics of charge movement, both electronic and ionic, through thin-film tungsten trioxide WO3 during either reduction or oxidation. The principal models are those of Faughnan and Crandall, Green, Ingram Duffy and Monk, and of Bohnke. Adjuncts and adapt…
Low-temperature sintering of (Pb 0.86 Ba 0.04 Sr 0.12 )(Zr 0.56 Ti 0.44 Sb 0.02 )O 3 (PBSZT) powders was investigated using Pb 5 Ge 3 O 11 (PGO) or LiBiO 2 (LBiO) as sintering aids. 1 wt% PGO or 1 wt% LBiO-added PBSZT powders could be densified into sintered bodies at 800°C for 2 h with a relative density of approxima…
We have investigated the dependence of the mechanoluminescence intensity from Sr3Al2O6: Eu on compressive stress. The distribution of the mechanoluminescence intensity, which is clearly visible to the naked eye, is consistent with the calculated stress distribution. The luminescence centre has been identified as the E…
We shall discuss our recent high pressure Raman studies on single wall carbon nanotube (SWNT) bundles and compare them with pressure-induced amorphous and polymeric phases of crystalline C60 and C70. Our high pressure Raman studies on SWNT bundles carried out upto 25.9 GPa show that the intensities of both the radial…
Carbonates are one of the most important group of minerals that fix phosphates in soils. Magnesium and silicon are known to reduce the P fixation of calcite. The effect of Mg and Si addition on P sorption–desorption of a mixture of 90% clay and 10% calcite was studied. The mixtures were montmorillonite–calcite (Mont–C…
Single-wall carbon nanotubes, seamless cylindrical molecules formed from a graphene sheet, are either conducting or semiconducting, depending on the particular "wrapping vector" that defines the waist of the tube. Scanning tunneling microscopy experiments have tested this idea by simultaneously measuring a tube's latt…
Amorphous boron-carbon-nitrogen (BCN) powders were produced by mechanically milling a mixture of hexagonal boron nitride (h-BN) and graphite powders for 120 h in an argon atmosphere. By annealing the amorphous BCN powders isothermally under 4 GPa at temperatures above 880 K, a new B–C–N crystal with a tetragonal struc…
We propose a POS (Piezo on Silicon) actuator, which comprise piezoelectric materials on a silicon substrate, and the actuation mechanism uses a bending vibration of a unimorph structure. Realization of this device was attempted, and the low-temperature sintering of piezoelectric ceramics, optimization of the screen-pr…
Results from the literature and unpublished ones of the present authors are summarized which are relevant to the mechanisms governing the mobility of dislocations in icosahedral Al-Pd-Mn quasicrystals. These results concern macroscopic deformation tests, conventional transmission electron microscopy, in situ straining…
Polypropylene/CaCO3 composites were homogenized in a twin-screw compounder and then injection molded into tensile bars. Six different fillers were used in a wide range of average particle sizes between 0.08 and 12 μm. Tensile and flexural properties were measured by standard techniques, while impact resistance was det…
In body centred cubic (bcc) crystals at low temperatures, the thermally activated motion of screw dislocations by the kink-pair mechanism governs the yield properties and also affects the strain hardening properties. In this work, the average strength of dislocation junctions is derived and numerically estimated in th…
The introduction of rubbery particles can be applied to enhance shear yielding and, consequently, the toughness of brittle amorphous polymers. The critical transition in these polymers from crazing to shear yielding requires a submicrometer- or even nanometer-sized rubbery phase. These can be obtained via coalescence…
Lithium chloride was found to be an effective and biocompatible catalyst for the ring-opening polymerization of lactide in the presence of hydroxyl-containing compounds. Ethylene glycol (EG) and methyl α-D-glucopyranoside (MGlc) were used as multifunctional initiators. The polymerization was carried out at 128°C in bu…
The quality of organic low-k methylsilsesquioxane (MSQ) film is degraded by the damage of oxygen plasma and hygroscopic behavior during photoresist stripping. In addition, the interaction between MSQ and copper is worth investigating. In this work, we have studied the H2 plasma treatment to improve the quality and enh…
Zinc oxide films were deposited on glass substrates in argon and oxygen atmosphere by dc reactive magnetron sputtering using a metallic zinc target. The influence of oxygen pressure and substrate temperature on the structure and optical properties of the films were systematically investigated and optimised the deposit…
During the past 15 years NASA has taken the lead role in exploiting the benefits of textile reinforced composite materials for application to aircraft structures. The NASA Advanced Composites Technology (ACT) program was started in 1989 to develop composite primary structures for commercial transport airplanes with co…
Results of experiments concerning nonlinear effects for elastic waves in metal rods with the crack-type defects are presented. The dependence of the nonlinear effect on the contact type is discussed. The crack has been modeled by cutting a rod and tightly filling the crack with metal plates. Two types of contact have…