Materials Literature
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The structures of poly(p-hydroxybenzoic acid) (PHBA) at the two high-temperature phase transitions (ca. 340 and 430 °C) have been investigated by X-ray powder diffraction methods (X-ray tube focusing and synchrotron parallel beam), chain conformation/packing models, and dielectric measurements. The structure of PHBA b…
A successful design of a 25 hp permanent-magnet synchronous motor using SmCo/sub 5/ and NdBFe magnets is presented. Expressions to predict the motor run-up and terminal performance are given. The rotor was tested for the straight interior rotor magnet arrangement. A record efficiency of over 94% was obtained at full l…
Abstract The dehydration of gypsum CaSO 4 .2H 2 O has been studied, at negligible water vapour pressure, by in situ infrared (IR) spectroscopy and by thermogravimetry to determine whether intermediate phases (CaSO 4 . n H 2 O) exist, other than the hemihydrate with n =0.5, and also to compare the mechanism of the dehy…
Slow strain rate testing (SSRT) was initially developed as a rapid, ad hoc laboratory method for assessing the propensity for metals and environments to promote stress corrosion cracking. It is now clear, however, that there are good theoretical reasons why strain rate, as opposed to stress per se, will often be the c…
Abstract By using an automated low‐frequency apparatus, dynamic mechanical experiments are performed on bulk‐crystallized high‐density polyethylene in the temperature range of the α relaxation. In order to characterize the key morphological features governing the presence of multiple α relaxations, we have developed a…
Climate strongly influences soil clay mineralogy and bulk chemical composition. In humid climates chemical weathering is at its most intense and virtually all ‘primary’ bedrock minerals suffer complete breakdown. They are replaced by authigenic hydrated oxides of Fe and Al together with halloysite and kaolinite in dee…
Low molecular weight liquid crystals with in‐build charge transfer (CT) properties have been generated from both liquid crystalline (LC) and non‐LC disc‐like compounds by doping these electron rich species with electron acceptors e.g. TNF. The influence of CT interactions on the columnar phases formed are assessed and…
The influence of R ‐curve behavior of ceramics on the strength degradation associated with thermal shock is explored. Of particular significance for this interdependence is the observed nonlinear stress‐strain behavior of materials that exhibit minimal strength degradation under severe thermal shock conditions. These…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPoly(aryl ether phenylquinoxalines)James L. Hedrick and Jeff W. LabadieCite this: Macromolecules 1990, 23, 6, 1561–1568Publication Date (Print):March 1, 1990Publication History Published online1 May 2002Published inissue 1 March 1990https://pubs.acs.org/doi/10.1021/ma00208a0…
The Landau model of Slonczewski and Thomas (1970) for the improper ferroelastic ${\mathit{O}}_{\mathit{h}}^{1}$-${\mathit{D}}_{4\mathit{h}}^{18}$ phase transition in perovskite-structure compounds has been extended by including spatial gradient terms of the three-component primary order parameter (OP) and applied to c…
A new formalism for use in atomistic simulations to calculate the full local elastic-constant tensor in terms of local stresses and strains is presented. Results of simulations on a high-angle (001) twist grain boundary are illustrated, using both a Lennard–Jones potential for Cu and an embedded-atom potential for Au.…
Abstract A study was conducted to determine the influence of organic matter on the solubility of Al in organic soil horizons from different geographic regions. Results showed that the equilibrium solubility of Al was dependent on solution pH and the degree to which the soil organic matter was saturated with Al. Plots…
Positively charged zinc containing or metal free phthalocyanines 6a-c and 7a-c were prepared via a three step procedure starting from 4-nitrophthalonitrile. The phthalocyanines contain alkyl chains of different length in order to influence the hydrophilic vs lipophilic character of the compounds. The partition between…
Organic coatings on phosphated and bare mild steel exposed to aqueous sodium chloride solutions were investigated by electrochemical impedance spectroscopy (EIS). The corrosion protection of coatings is well characterized by a thorough transfer function analysis of the EIS data obtained. A quasi-homogeneous and two di…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of porous quantum-size cadmium sulfide membranes: photoluminescence phase shift and demodulation measurementsLubomir Spanhel and Marc A. AndersonCite this: J. Am. Chem. Soc. 1990, 112, 6, 2278–2284Publication Date (Print):March 1, 1990Publication History Published…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of photolabile precursors of amino acid neurotransmittersMary Wilcox, Randall W. Viola, Katherine W. Johnson, Andrew P. Billington, Barry K. Carpenter, James A. McCray, Anthony P. Guzikowski, and George P. HessCite this: J. Org. Chem. 1990, 55, 5, 1585–1589Publicat…
ABSTRACT Three diatom species, Stephanodiscus hantzschii (Ehr.) Grun., Asterionella formosa Hass. and Fragilaria crotonensis Kitt. Hass. were isolated from Lake Maarsseveen where they are dominant and show a successional sequence. The physiological responses of each species to temperature and limitation by silicon and…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDepth dependence of direct and indirect photolysis on soil surfacesVincent R. Hebert and Glenn C. MillerCite this: J. Agric. Food Chem. 1990, 38, 3, 913–918Publication Date (Print):March 1, 1990Publication History Published online1 May 2002Published inissue 1 March 1990https…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTemplate-driven self-assembly of a porphyrin-containing supramolecular complexJohn S. Manka and David S. LawrenceCite this: J. Am. Chem. Soc. 1990, 112, 6, 2440–2442Publication Date (Print):March 1, 1990Publication History Published online1 May 2002Published inissue 1 March…
The comparative study of the intumescent formulations (poly propylene-ammonium polyphosphate-pentaerythritol) and (polypropylene- ammonium pyrophosphate-pentaerythritol) shows that the highest fire retar dance property of the second system may be related to the existence of a protective carbonaceous coating stable in…