Materials Literature
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The Mössbauer spectroscopy has been applied to iodine-doped polyacetylene employing 129 I. It is found that the polymer films contain I - , I 3 - and I 5 - with symmetrical charge population, where the content of each iodide anion depends on the doping level. Under dynamic evacuation, it is elucidated that I 5 - conve…
The microstructure of many electroceramic components based on barium titanate is dominated by anomalous grain growth. At firing temperatures below the eutectic temperature nearly all large crystallites were found to contain lamellae. The crys‐tallographic orientation of these lamellae was studied by TEM. By combining…
Using Beta/Beta prime dimethypyrrole polymers to reduce the structural disorder it has been possible to interpret the results of electron diffraction data and to propose and idealized structure for neutral polypyrrole. XPS data have been used to define some of the deviations from this ideal structure that are seen in…
Bovine and lathyritic rat type III collagen preparations were analyzed for the presence and in vitro formation of intermolecular disulfide cross-links. Type III collagen from fetal bovine skin was extracted with the aid of pepsin and purified by differential salt precipitation, guanidine denaturation, and renaturation…
It is shown that the orientation dependent excluded volume interaction between elongated nematic molecules and the cell walls always favors the planar alignment of nematic liquid crystals. For thermotropic liquid crystals the anchoring energy of this effect amounts to several erg/cm 2 .
The tensile flow stressσ∊ has been studied for super-pure and commercial aluminium and for an Al-21/4% Mg alloy in relation to strain, grain size d, subgrain or cell size and dislocation density ρ. At room temperature and 200°C, the flow stress depends on both ρ1/2 and d −1/2. This is interpreted an evidedce of a requ…
Post Pond Volcanics, Vermont; transmission electron microscopy and diffraction. The chlorite occurs in intergrown 1-layer and disordered polytypes, the wonesite occurs in 1-layer, 2-layer, 3-layer, and disordered forms, and the biotite occurs as 1-layer and 2-layer polytypes with minor stacking disorder.--Modified jou…
Refinement in space group P6 3 /m to an R = 2.02%; confirmed to be isotypic with wadeite (K 2 ZrSi 3 O 9 ). The atomic charges of Si VI , Si IV , O(1) br and O(2) nbr are +3.3, +2.5, -1.4 and -1.4, respectively, and suggest that an increase in the coordination number of a Si atom from 4 to 6 significantly increases th…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDesign, preparation and ESR detection of a ground-state nonet hydrocarbon as a model for one-dimensional organic ferromagnetsYoshio Teki, Takeji Takui, Koichi Itoh, Hiizu Iwamura, and Kazumasa KobayashiCite this: J. Am. Chem. Soc. 1983, 105, 11, 3722–3723Publication Date (Pr…
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A procedure to estimate the standard molar heat capacity, relative enthalpy, and calorimetric entropy of silicate minerals has been devised and evaluated. These are estimated by summing, in appropriate proportions, fictive molar isobaric heat capacities, relative enthalpies, and entropies evaluated for structural comp…
The synthesis and assembly of vimentin was studied in erythroid cells from 10-d-old chicken embryos. After various periods of [35S]methionine incorporation, cells were lysed in a Triton X-100-containing buffer and separated into a soluble and an insoluble (cytoskeletal) fraction. Analysis of these two fractions by two…
Large, hard ZrO 2 agglomerates remained in an Al 2 O 3 /ZrO 2 composite suspension after inefficient ball‐milling. The ZrO 2 agglomerates shrank away from the consolidated Al 2 O 3 /ZrO 2 powder matrix during sintering, producing crack‐like voids which were responsible for strength degradation.
Abstract A series of polypropylene (PP)/nylon 6 (N6) blends of composition 75/25, 50/50, and 25/75 have been prepared in a screw extruder combined with a Koch static mixer. The phase morphology was observed with a scanning electron microscope. The influence of heating in the reservoir of a rheometer followed by subseq…
High-resolution ac calorimetric, x-ray, and light-scattering measurements have been made on $\mathrm{N}\ensuremath{-}[4\ensuremath{-}(n\ensuremath{-}\mathrm{butyloxy})\mathrm{benzylidene}]\ensuremath{-}{4}^{\ensuremath{'}}\ensuremath{-}(n\ensuremath{-}\mathrm{heptyl})\mathrm{aniline}$ (4O.7) near the nematic-smectic-$…
Abstract The activities of thermodynamic components of clay minerals corresponding in composition to pyrophyllite, muscovite, paragonite, and margarite were computed from chemical analyses reported in the literature assuming ideal mixing of atoms on homological sites in the minerals. These activities were then used to…
The nucleotide sequence of two recombinant plasmids containing hamster vimentin cDNA was determined. The sequence comprises 1,640 base pairs and reveals virtually the total primary structure of vimentin and a large part of the 3' noncoding region. Secondary structure prediction methods allow the characterization of tw…
E. Prince Mathematical Techniques in Crystallography and Materials Science. Berlin, Heidelberg, and New York (Springer-Verlag), 1982. viii+ 192 pp., 28 figs. Price DM 55.00 ($25.60). - Volume 47 Issue 343
The unipolar structure that is the steady self-biased hysteresis loop can be created by the electrothermal annealing in the paraelectric phase of pure TGS-crystals grown in the ferroelectric phase. It also occurs in X-irradiated TGS and TGS-Cr. The formation of unipolarity in all these crystals is due to the same spec…
Abstract We describe the syntheses and properties of the new Wurster-type acceptors, 3,7-dihalo-2H,6H-benzo[1,2-b:4,5-b′]dithiophene-2,6-diones (2a) and (2b), which have C2h molecular symmetry with two sulfur atoms, together with the electrical resistivities of their CT complexes.