Materials Literature
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Electron localization in the methyl-ring-substituted derivative of polyaniline (PAN), poly(o-toluidine) (POT), has been investigated by transport and magnetic measurements. The HCl salt of POT shows greater electron localization than that of PAN due to decreased interchain diffusion rate caused by increased interchain…
Barkhausen effect (BE) phenomenology in iron-based ferromagnetic alloys is investigated by a proper experimental method, in which BE experiments are restricted to the central part of the hysteresis loop, and the amplitude probability distribution, P0(Φ̇), and power spectrum, F(ω), of the B flux rate Φ̇ are measured un…
The Barkhausen effect (BE) in metallic ferromagnetic systems is theoretically investigated by a Langevin description of the stochastic motion of a domain wall in a randomly perturbed medium. BE statistical properties are calculated from approximate analytical solutions of the Fokker–Planck equation associated with the…
Measurements are reported for the dc as well as frequency-dependent (ac) conductivities (real and imaginary parts) for various compositions of the vanadium germanate glassy semiconductors in the temperature range 80--450 K. The experimental results are analyzed with reference to various theoretical models proposed for…
The dielectric relaxation of a solid solution of 10-mol % lead titanate in lead magnesium niobate is found to be similar to the magnetic relaxation in spin-glass systems.1–3 Based on this analogy, it is proposed that the relaxor ferroelectric is a polar-glassy system which has thermally activated polarization fluctuat…
The authors derive a simple analytical solution that accurately describes the evolution in time of breath figures, i.e. the fogging that occurs when a vapour condenses onto a 'cold' surface.
Uniformly thick, conductive, tin oxide thin films ranging in thickness from 3 to 85 nm were deposited by reactive evaporation of tin, in the presence of oxygen, onto heated glass substrates. The conductivity of the films could be increased by doping with molybdenum using a simple, novel technique which is described. F…
Contact charge exchange measurements have been made on polytetrafluoroethylene (PTFE) films charged by repeated contacts to mercury. The authors have shown previously that charge accumulates with repeated contacts until the surface reaches saturation, and that the saturation potential is strongly affected by impuritie…
Despite the recognition of several sources of variation of contact angle, both between and within sessile drops on plane substrates, no comment has ever been made on the statistical treatment of observed angles, especially those around single drops. Circumperipheral observations are suggested as essential, and analysi…
Parallel‐ and perpendicular‐polarized Raman and KBr pellet transmission IR spectra of quenched 10K 2 O‐50SiO 2 ‐nR 2 O 3 (R = La, Gd, Yb; n = 0, 1, 5, 10 mol) glasses are presented. Increasing lanthanide oxide concentration produces partially‐polarized high‐frequency bands at 1030, 940, and 860 cm −1 , assigned to the…
The resolution in optical scanning microscopy is limited by the numerical aperture N.A. of the objective and the wavelength of the light lambda, so that the modulation transfer is zero beyond the spatial frequency of 2 N.A./lambda. However, when an optical property of the object changes under the influence of the scan…
The influence of pressure, temperature, and bulk composition on the structure of di‐ and tetra‐aluminosilicate melts and quenched melts have been studied with Raman spectroscopy. The melt polymerization and Al/(Al + Si) ranges represented are those typically found in quartz‐normative basaltic magmatic liquids. The rea…
Melt viscosities and densities of isobarically quenched melts (glasses) have been determined for K 2 Si 4 O 9 up to pressures of 2.4 GPa. At 1200°C, melt viscosity decreases linearly from 1700 P at 1 atm to 310 P at 2.4 GPa. The increase in glass density with increasing pressure is described by a Birch‐Murnaghan equat…
Epitaxial yttria-stabilized zirconia films were grown on Si (100) and Si (111) by pulsed laser deposition. Rutherford backscattering spectroscopy indicates a high degree of crystalline perfection with a channeling minimum yield of 5.3%. A necessary predeposition process is removal of native silicon oxide from the Si p…
Abstract Thermal and mechanical properties were measured for solvent‐cast films of cellulose acetate propionate plasticized with triphenyl phosphate. Probabilistic models for the glass transition temperature, tensile heat deflection temperature, tensile modulus, break stress, and initial tear strength as functions of…
Abstract Antifoam compositions for aqueous surfactants are usually emulsions of insoluble oils containing hydrophobic solids. The emulsion allows easy access to the aqueous environment. The oil droplets carry the solid particles to the foam interfaces by spreading, which also contributes to foam rupture. The particles…
Abstract The preparation of PVA films and fibers with high modulus and high strength was examined. The high drawing was attained when both the drawing just before melting and the relaxation at room temperature were repeated. The maximum draw ratio was 40 for the films prepared from the gels of high molecular weight (H…
Abstract Extrusion‐blown film prepared from a semidry mixture of starch and poly(ethylene‐co‐acrylic acid) (EAA) cannot be sharply separated into its polymeric components by selective solvent extraction, and the two polymers have the outward appearance of being compatible. Also, the starch portion is resistant to enzy…
Abstract Linear low density polyethylene (LLDPE) was reinforced with wood fiber, glass fiber, and mica. The effect of aging on mechanical properties of the composites was examined under different conditions: (i) exposure at 105°C for 7 days; (ii) immersion in boiling water for 4 h. Samples containing glass fibers show…
Abstract Polyethylene and polystyrene composites filled with high‐volume content of filler particles (quartz or Al 2 O 3 ) were prepared by ordinary melt‐casting method to effectively increase the thermal conductivity. The result, however, suggested that fractional void volume cssentially occupied by filler particles…