Materials Literature
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Poled guest-host polyquinoline thin films are shown to demonstrate both exceptionally large electro-optic activity and long-term thermal stability. After an initial drop from 45 pm/V to 26 pm/V in the first 100 hours, the electro-optic coefficient r<SUB>33</SUB> at 26 pm/V remained for more than 2000 hours.
We studied conductive polymers as an anti-corrosion coating on 7075-T6 aluminum alloys. A double strand polyaniline molecular complex was used as the coating material. The new double strand polyaniline complex is advantageous compared with the traditional polyaniline by improvements in processability and stability. Po…
Extensive gel permeation chromatography coupled with surface structure and mechanical property measurements clearly indicate that polyaniline in the base form has a tendency to aggregate or agglomerate as a result of intermolecular hydrogen-bonding. The aggregation is present in the solid state powder. The degree of a…
In this communication we report results obtained in our laboratory on the design, the synthesis, and the characterization of new light-emitting copolymers. We are interested in block copolymers containing well defined conjugated sequences, which give rise to luminescence. Those chromophores, which are (pi) -conjugated…
Materials which possess transparency, coupled with active controllability of this transparency in the infrared (IR), are today an increasingly important requirement, for varied applications. These applications include windows for IR sensors, IR-region flat panel displays used in camouflage as well as in communication…
Permeability spectra in Ni-Zn ferrite composite materials were studied at the volume loading of ferrite above 30% and at temperatures from 100 to 400 K. The permeability decreased with decreases in the volume loading of ferrite. This decrease was much larger than that expected from the empirical mixing law. This was a…
Within the framework of the generalized multiple-scattering theory, a conceptually clear and transparent derivation of the real-space screened Korringa-Kohn-Rostoker method is presented. It is suggested that, by a suitable choice of the reference system, a fast exponential spatial decay of the structure constants can…
The static electric polarizability tensor of single-wall carbon nanotubes is calculated within the random-phase approximation using a simple tight-binding model and a classical correction to include local fields. We find that the polarizability for constant fields parallel to the cylindrical axis is highly dependent o…
Using first-principles band-structure theory we have systematically calculated the (i) alloy bowing coefficients, (ii) alloy mixing enthalpies, and (iii) interfacial valence- and conduction-band offsets for three mixed-anion (CuInX2, X=S, Se, Te) and three mixed-cation (CuMSe2, M=Al, Ga, In) chalcopyrite systems. The…
The fundamental absorption edge of the anatase phase of ${\mathrm{TiO}}_{2}$ has been studied by performing polarized optical transmission measurements on single crystals at temperatures ranging from 4.2 to 300 K. An Urbach tail has been found that shows an exponential spectral dependence down to liquid-helium tempera…
Field emission of electrons from individually mounted carbon nanotubes has been found to be dramatically enhanced when the nanotube tips are opened by laser evaporation or oxidative etching. Emission currents of 0.1 to 1 microampere were readily obtained at room temperature with bias voltages of less than 80 volts. Th…
The dynamics of spreading of small amounts of viscous fluids are usually investigated using spherical droplets of oils. Recently we applied Frenkel's method to this problem and obtained a wide angle relation between the edge speed and the dynamic contact angle and this gave good agreement with literature data. In this…
Ion beam sputtering and dual ion beam sputtered films of titanium oxide were prepared and investigated at room temperature and compared with similar films prepared by e-beam (EB) gun deposition. Optical properties, i.e. Refractive index n and extinction coefficient k of films were determined by transmission spectropho…
Abstract An on‐line sensor for estimating conversion from measurements of ultrasound propagation velocity in emulsion polymerizations has been developed. The sensor does not require a sampling circuit, because it can be directly plugged in the reacting mixture. The performance of the sensor has been tested by comparis…
Abstract Nylon 6 was prepared by adiabatic anionic polymerization of ϵ‐caprolactam using hexamethylene dicarbamoyl dicaprolactam (HDC), cyclohexyl carbamoyl caprolactam (CCC), or phenyl carbamoyl caprolactam (PCC) as activators and sodium caprolactamate (NaCL) as a catalyst at various initial reaction temperatures ran…
Abstract This article describes a number of chemical routes for the recycling of sheet‐molding compounds (SMC) consisting of glass fibers, filler (calcium carbonate), and an unsaturated polyester–styrene thermoset resin. Treatment of milled SMC with ethanol/potassium hydroxide at 85°C for 48 h ultimately affords a sol…
Efficient conversion of infrared radiation centred at 1 mu m into visible luminescence has been observed in cubic Cs 2 NaErCl 6 crystals in which electric dipole transitions are forbidden by symmetry selection rules. Luminescence originating from the 4 F 9/2 and 4 T 9/1 levels of Er 3+ increases strongly with increasi…
We report a dependence of the photoabsorption cross section as measured by total electron yield at the Fe and Co $3p$ thresholds on the sign of the magnetization for $p$-polarized light at oblique incidence. Peak-to-peak asymmetries up to 4% are observed. The asymmetry increases towards grazing incidence, where the to…
We propose a phase-field model for the kinetics of isothermal crystallization of an amorphous solid at a concentration nearly equal to the equilibrium crystal stochiometry. The model utilizes two coupled fields: a nonconserved ordering vector field which describes the local lattice structure and a conserved nonorderin…
We have used molecular dynamics and simulated annealing to study an asymmetrical $\ensuremath{\Sigma}3$ tilt grain boundary with $〈211〉$ rotation axis in Cu. The boundary plane was inclined at 84\ifmmode^\circ\else\textdegree\fi{} with respect to the ${}\left(111\right)$ plane. A simple central force $N$-body interato…