Materials Literature
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The effect of lateral substituents on the type and thermodynamic stability of the mesophases shown by terminally polar and nonpolar rod-like mesogens is described. Lateral substituents both sterically force the interacting molecules apart and also hinder the packing of the molecules in a layered structure, thus suppre…
The nebulosities around five optically selected (by UV excess) luminous QSOs have been observed spectroscopically. 3C 273, which has been observed off-nucleus before, has nebulosity dominated by a stellar continuum. TON 202, a steep-spectrum radio source, has nebulosity dominated by strong Balmer and [O III] emission…
Abstract A range of authigenic sedimentary chlorites from sandstones has been studied by analytical transmission electron microscopy. Selected area (single crystal) electron diffraction patterns are of the I b ( β = 90°) polytype confirming the earlier observations of Hayes (1970). TEM analyses show all samples to be…
The crystal structure of cubic barium titanate was determined at five temperatures up to 180 °C, using the data collected by an X-ray automatic four-circle diffractometer. At temperatures between the Curie temperature and about 180 °C, the Ti atom is displaced from the center of the unit cell along the <111> direction…
The addition of small amounts of iron to the shape-memory alloy Ti-Ni suppresses the martensitic transition, permitting a detailed study of ``premartensitic'' effects. Using x-ray and neutron-diffraction data, specific-heat, resistivity, and susceptibility measurements, we show that two distinct phases appear. The fir…
Solid catalysts in common use are typically in the form of small metal crystallites dispersed on the internal surface of the porous support. Advantages of these supported-metal catalysts lie in their high surface-to-volume ratio and the high thermal stability endowed by the dispersion. Such catalysts are commonly prod…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHighly amorphous, birefringent, para-linked aromatic polyamidesH. G. Rogers, Russell A. Gaudiana, W. C. Hollinsed, P. S. Kalyanaraman, J. S. Manello, C. McGowan, R. A. Minns, and R. SahatjianCite this: Macromolecules 1985, 18, 6, 1058–1068Publication Date (Print):June 1, 198…
The gene for the major phosphofructokinase enzyme in Escherichia coli, pfkA, has been sequenced. Comparison of the amino acid sequence with other phosphofructokinases showed that this enzyme is related to the Bacillus stearothermophilus and rabbit muscle enzymes, but is different from the second, minor phosphofructoki…
The three-dimensional structure of ubiquitin has been determined at 2.8 A resolution. X-ray diffraction data for the native protein and derivatives were collected with an automated diffractometer. Phases were obtained by use of a single isomorphous mercuric acetate derivative. The molecule contains a pronounced hydrop…
The oxidation and reduction of metal phthalocyanines give rise to at least six oxidation states whose electronic spectra are rationalized in some depth in terms of SCF energies, Coulomb and exchange integrals. It is shown that a single set of parameters can reproduce the Q band energies moderately well. Further this s…
Abstract Melt fabricated plastic articles with improved solvent and vapor barrier properties are of great need in the packaging industry. Various techniques, such as coextrusion, surface treatments, and coatings, are being employed currently towards this objective. Present work has identified a unique polymer blend ap…
Solid‐state 29 Si and 27 Al NMR spectra of kaolinite fired at 800° to 1450°C, interpreted in light of a newly proposed metakaolinite structure and complementary X‐ray diffraction results, lead to the following conclusions about the hightemperature reactions: (1) Removal of the final residual hydroxyl radicals of metak…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDimerization of cobalt(II) tetrasulfonated phthalocyanine in water and aqueous alcoholic solutionsYu Chu Yang, J. Richard Ward, and Reginald P. SeidersCite this: Inorg. Chem. 1985, 24, 12, 1765–1769Publication Date (Print):June 1, 1985Publication History Published online1 Ma…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe melt properties of ring polystyrenesJ. RooversCite this: Macromolecules 1985, 18, 6, 1359–1361Publication Date (Print):June 1, 1985Publication History Published online1 May 2002Published inissue 1 June 1985https://pubs.acs.org/doi/10.1021/ma00148a059https://doi.org/10.10…
Supported catalysts, one of the commonest forms of heterogeneous catalysts in practical use, consist of small crystallites of a catalytically active component dispersed in a porous support of high surface area. Impregnation of the support with an aqueous solution of a compound containing the appropriate catalytic comp…
Abstract The effect of ethyl benzoate (EB) as a component of the solid catalyst (“internal” base) and/or of the co‐catalyst (“external” base) on propene polymerization in the presence of different MgCl 2 ‐supported Ziegler‐Natta systems was investigated systematically. From the experimental results, it is suggested th…
Abstract Diagenetic illitic clays from seven North American bentonites of Ordovician, Devonian, and Cretaceous ages and from three subsurface North Sea sandstones of Permian and Jurassic ages have been examined by X-ray diffraction (XRD) and transmission and scanning electron microscopy (TEM and SEM). XRD indicates th…
Abstract To deformation and fracture behavior of several polypropylene (PP) and rubber‐modified PP materials have been investigated. Plastic deformation mechanisms of these systems depend upon the test rate and temperature with high rates and low temperatures being in favor of crazing. The ductility and toughness of t…
A model is presented in which the sintering behavior of a ceramic film which is constrained by a rigid substrate is contrasted with the sintering behavior of a free film. The problem is made simple by the assumption that the stress field developed in the film is uniform. This simplification allows several closed form…
Single crystals of phosphors have been prepared. Optical absorption spectra and stimulation spectra measured with polarized light are in good agreement with each other. The experimental ESR spectra of the F − ‐rich and X − ‐rich undoped powder phosphors which have been x‐rayed coincide with the calculated spectra of F…