Materials Literature
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The structure of nanocomposites fabricated using carbon nanotube templates using transmission electron microscopy and electron energy‐loss spectroscopy will be described here. Examples for filled, network substituted and uniformly coated nanotubes will be described. The novelty of such nanocomposite structures and the…
Several molecular devices based on the electronic switching properties of conducting polymers have been described previously and involve an addition/removal of a proton/electron to/from the polymer chain. This “doping” process creates charged topological defects such as polarons or bipolarons, which act as charge carr…
Magic angle spinning at sufficiently high rates dramatically changes the sample temperature. A method is described for calibrating a probe head for the thermal effects encountered during magnic angle spinning experiments. Using Sm2Sn2O7 as a chemical shift thermometer, the overlapping effects of ‘external’ heating or…
Film growth conditions were selected to enable the extent of migration of fluoride ions in anodic oxides on tantalum to be determined precisely. By using a preformed film formed in sodium orthosilicate electrolyte in which the incorporated silicon species are immobile, a marker is generated to which mobilities may be…
Other| February 01, 1997 Montmorillonite under high H2O pressures: Stability of hydrate phases, rehydration hysteresis, and the effect of interlayer cations Tzy-Chung Wu; Tzy-Chung Wu Cornell University, Department of Geological Sciences, Ithaca, NY, United States Search for other works by this author on: GSW Google S…
Average crystallite size and mean‐square strain of illite in rock specimens and clay separates were measured independently in TEM images and by single‐line Fourier (Voigt method) profile analysis of the c . 1 nm peak of XRD patterns for a prograde sequence of pelitic rocks (illite crystallinity indices=0.17–0.58°Δ2 θ…
Abstract A new procedure for the determination of the amounts of phases in samples of isotactic poly(propylene) quenched at different cooling rates from the same melted polymer is described. According to the procedure, all the patterns corresponding to the same quenching series are simultaneously analyzed for the amou…
A new type bistable reflective cholesteric liquid crystal display is reported. The texture and the relaxation process are very different from other types of the reflective cholesteric displays reported previously. The contrast ratio of the display is about 2.5 times higher than regular cholesteric displays. The respon…
Sliding wear properties of ultra‐fine‐grained (180 nm) yttria‐doped tetragonal zirconia (Y‐TZP) ceramics were examined with porosities from 1.5% to 7%. On a pin‐on‐plate tribometer under dry‐N 2 conditions, e.g., wear rates of the material increase by a factor of 5 by increasing porosity with a factor of 5 (from 1.5 t…
Optically reflective and surface-conductive polyimide films have been prepared by the incorporation of silver(I) acetate and trifluoroacetylacetone into a dimethylacetamide solution of the poly(amic acid) formed from 3,3‘,4,4‘-benzophenonetetracarboxylic acid dianhydride (BTDA) and 4,4‘-oxydianiline (4,4‘-ODA). Therma…
Abstract A sol‐gel granulation process was developed to prepare porous nanostructured γ‐alumina granules as supports for catalysts and adsorbents. The process, which starts with an aqueous sol of gelatinous boehmite, involves droplet formation, gelation in paraffin oil, conditioning in ammonia solution, and drying and…
The excitation and radiative recombination mechanisms of carriers in electroluminescent porous silicon (PS) have been studied for the device with the structure of Au/PS/n-type Si. Experiments focus on the electroluminescence (EL) and photoluminescence (PL) spectra, the current-voltage-EL intensity relationship and its…
The birefringence induced by partially ordered polymer networks dispersed in an isotropic phase of liquid crystals is studied. Polymer networks were formed by the polymerization of 1--4 % mixtures of prepolymer in the nematic phase of liquid crystals. The partial nematic (paranematic) ordering is analyzed in terms of…
The surface reduction of amorphous poly(aryl ether ether ketone) (PEEK) film was successfully achieved by wet chemistry using a solution of NaBH 4 in DMSO at 120 °C for 3 h. The resulting PEEK-OH film was fully characterized by MIR, UV−visible, and 1 H NMR spectroscopies; all the data were consistent with those of the…
Mandelate racemase (EC 5.1.2.2) catalyzes the abstraction of a proton from a carbon atom adjacent to a carboxylate function, a reaction which is kinetically and thermodynamically unfavorable. Proton NMR spectroscopy and polarimetry were used to measure the rates of deuterium incorporation into the alpha-position of ma…
Three series of copolymers have been prepared by the reaction of a mesogenic methacrylate, 6-((4-((4-methoxyphenyl)azo)phenyl)oxy)hexyl methacrylate, with either 4-vinylpyridine, 2-vinylpyridine or styrene. These copolymers were blended with either a mesogenic acid, 6-((4-((4-methoxyphenyl)azo)phenyl)oxy)hexanoic acid…
We present the results of ab initio calculations of the spin-polarized electronic structure of disordered bcc ${\mathrm{Cr}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Fe}}_{\mathrm{x}}$ and ${\mathrm{Mn}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Fe}}_{\mathrm{x}}$ alloys. The self-consistent calculations we…
Perovskite PbTiO 3 powders were prepared by a polymerized complex technique at relatively low temperatures, viz. 400−600 °C. Heating of a mixed solution of citric acid (CA), ethylene glycol (EG), and Pb and Ti ions with a molar ratio of Pb/Ti/CA/EG = 1/1/10/40 at 130 °C produced a yellowish transparent polymeric gel w…
A simple derivation is given to arrive at an expression for the Coulomb energy of a polar crystal with emphasis on its dependence on the external form of the crystal. It is found that the existing treatments are incomplete, since they refer to the central cell in the crystal, which may have an energy different from th…
This article relates to an investigation of injection moulding a new commercial polymer, an aliphatic polyketone (PK). A terpolymer and a 30% glass-filled grade were used as study materials together with an isotactic polypropylene that was used as a basis for comparison. Both conventional injection moulding and shear-…