Materials Literature
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We have observed step-flow growth of Si on sapphire, for the first time, by gas-source molecular beam epitaxy using ultrasmooth sapphire substrates, and self-formed Si quantum wires were fabricated on the substrates. The wires were aligned along the substrate steps and formed uniformly with 50 nm width and 1 nm height…
The tensile strength distribution of fibres is a key constitutive property of fibre reinforced composites and is often described using Weibull statistics. However, the standard experimental methods used for obtaining the Weibull parameters are tedious and prone to error. In this paper, Weibull parameters of polycrysta…
We have fabricated perovskite La1−xKxMnO3 (x=0.14 and 0.2) thin films on SrTiO3 (100) by e-beam/thermal coevaporation. From the electrical and magnetic studies, we found a simultaneous occurrence of the paramagnetic to ferromagnetic state and insulating to metallic state, as predicted by the double exchange theory. Th…
Inelastic neutron scattering spectra were measured for amorphous ice ${\mathrm{H}}_{2}\mathrm{O}$ and ${\mathrm{D}}_{2}\mathrm{O}$ produced by low-temperature and low-rate vapor deposition. The data show that the deposition produced the low-density amorphous form of ice, i.e., the high-density amorphous ice observed b…
Fast proton-conducting P2O5–ZrO2–2SiO2 glasses were successfully prepared by the hydrolysis of metal alkoxides. The glasses obtained by heating at 150 to 400 °C are chemically stable and exhibit high conductivities of ∼104 S/cm at room temperature, conductivities that are higher by ∼4 order than that of glasses contai…
A kinetic treatment of the transport of mobile molecules in nanometer channels is presented, that explores ideas of the Enskog theory of dense gases combined with molecular relaxation to the substrate. Transport diffusivity is shown to increase strongly with density, as an effect of effective transfer of mass in the n…
Palladium single crystals have been found to be active for the C–H bond dissociation of methane in the temperature range 400–600 K, and the activities of the presently investigated Pd(111) and Pd(311) surfaces are compared with previously studied Pd(679). Structure sensitivity is reported that spans an order of magnit…
We report on a solution processed novel electroluminescent heterostructure device consisting of an inorganic semiconductor, CdS, and a polymer emitter, poly(p-phenylene vinylene) (PPV). This configuration provides the advantage of excellent charge transporting properties of an inorganic semiconductor and the high lumi…
Highly oriented and columnar grained diamond layers only a few microns thick, deposited at different substrate temperatures (500, 550, and 800 °C) on silicon using microwave-plasma-assisted chemical vapor deposition, are investigated by special photothermal techniques and high-resolution transmission electron microsco…
Electrically switchable diffractive gratings based on cholesteric liquid crystals are suggested. An electric field switches the cholesteric cell between three states: two with a uniform in-plane director and one with a periodic in-plane director modulation. The modulated state produces a Raman–Nath diffractive effect.…
Using a realistic model, the mode Gr\"uneisen parameters $\ensuremath{\gamma}$ and the temperature dependent coefficient of linear thermal expansion $\ensuremath{\alpha}(T)$ are calculated for amorphous silicon. The resulting $\ensuremath{\gamma}$ values differ from the crystalline case in having all diversity suppres…
Field emission has been measured from a series of tetrahedrally bonded amorphous carbon (ta-C) films produced by the filtered cathodic vacuum arc. The threshold field and current densities achievable have been studied as a function of their sp3 content and of nitrogen incorporation. Typical undoped ta-C films are foun…
New “112” phases, LnBaCo2O5.4, with an ordered oxygen deficient perovskite structure, derived from the YBaFeCuO5-type were studied for Ln=Eu, Gd. The appearance of giant negative magnetoresistance in this structural type is demonstrated. Resistance ratio R0/R7 T reaches at least 10 at 10 K, i.e., is significantly larg…
An anomalous negative temperature dependence of electrical resistivity has been observed in $({\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{V}}_{x}{)}_{3}\mathrm{Al}$ alloys with V compositions up to $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.35$. In particular, the Heusler-type ${\mathrm{Fe}}_{2}\mathrm{VAl}$…
This paper presents a new modelling of positive-discharge development, based on new simplifying assumptions. It presents these assumptions, which are deduced from the existing theoretical models and concern mainly the coupling between the leader corona and the corona region. This model has been validated through the c…
Three-component composites consisting of polypropylene (PP) matrix, poly(vinyl butyral) (PVB) modifier, and mica filler at various ratios of matrix to modifies and a constant mica content (30 wt %) were prepared by using two different kinds of PVB, viz., PVB and PVB-P. By correlating with the morphology, the dynamic m…
Sulfur prevulcanization of natural rubber latex was conducted at 60, 70, 80, and 90°C for different periods. The extent of crosslinking was assessed. Tensile properties, water absorption, leaching, and stress-relaxation characteristics of the films were also evaluated. The volume fraction of rubber (Vr), which is a me…
The melting and crystallization behavior and phase morphology of poly(3-hydroxybutyrate) (PHB) and poly(DL-lactide)-co-poly(ethylene glycol) (PELA) blends were studied by DSC, SEM, and polarizing optical microscopy. The melting temperatures of PHB in the blends showed a slight shift, and the melting enthalpy of the bl…
A new crystalline form and a solvate of glibenclamide were prepared and characterized by hot-stage microscopy, DSC, IR, scanning electron microscope, X-ray powder diffraction and dissolution studies. From I, III and the solvate which melt at 174.4, 153.2 and 109.3 degrees C, were obtained by crystallization. Significa…
Synthesized poly(ester)urea-urethanes with 14C-labeled toluene diisocyanate or 14C-labeled chain extender ethylene diamine were incubated with cholesterol esterase in a phosphate buffer solution at 37 degrees C. A number of biodegradation products, generated at the level of 2.8 micrograms/cm2 of polymer surface area,…