Materials Literature
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Helium bubble nucleation has been studied at grain boundaries in a ternary austenitic steel after helium implantation in the temperature range 450–600°C. Transmission electron microscopy shows that all interfaces except the coherent twin are preferred nucleation sites for bubbles, and that the density of bubbles is gr…
Measurements are reported of the temperature dependence of the proton spin-lattice and spin-spin relaxation times ${T}_{1}$ and ${T}_{2}$ in yttrium and lanthanum dihydrides containing controlled levels of gadolinium as low as 50 ppm. The results demonstrate unambiguously that paramagnetic ions in concentrations so lo…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAnthracene pillared cofacial diporphyrinC. K. Chang and Ismail AbdalmuhdiCite this: J. Org. Chem. 1983, 48, 26, 5388–5390Publication Date (Print):December 1, 1983Publication History Published online1 May 2002Published inissue 1 December 1983https://pubs.acs.org/doi/10.1021/j…
A biotite that has substantially altered to chlorite in a granitic rock from south-central Maine has been investigated with high-resolution and analytical transmission electron microscopy. The reaction takes place primarily by the replacement of TOT mica layers in the biotite by brucite-like layers (mechanism 2). This…
Magnesian calcites with compositions between 0 and 24 mole% MgCO 3 were synthesized at high temperatures and pressures in cold-seal pressure vessels and in a piston-cylinder apparatus. X-ray powder diffraction and atomic absorption analyses of these phases reveal a non-linear, but smooth, variation in volume and c/a w…
A single-crystal X-ray study indicates that the perovskite form of CaGeO 3 is orthorhombic (Pbnm), and isotypic with GdFeO 3 , although it was previously reported as a cubic form. The crystal structure is close to that of Sm-AlO 3 . Although the unit cell of CaGeO 3 is pseudocubic, the structure itself is very distort…
The interatomic coupling of magnetic moments in the insulating antiferromagnetic transition-metal compounds MnO, MnS, and NiO is calculated using a theory based on the itinerant-electron picture (energy-band theory and the local-spin-density treatment of exchange and correlation). Calculated values of these "Heisenber…
Abstract Epitaxial crystallization of polyethylene, n ‐paraffins, aliphatic polyesters, and various polyamides has been achieved on benzoic acid crystal substrates, specifically on their (001) crystals faces, which are made up of the aromatic rings. The epitaxial relationship is very similar for all polymers investiga…
Raman spectra are reported for crystalline anorthite (An), calcium Tschermak's pyroxene (CaTs), gehlenite (Geh), and glasses of CaAl 2 Si 2 O 8 (An), CaAlAlSiO 6 (CaTs), and Ca 2 AlAlSiO 7 (Geh) composition. A small degree of Si-Al disorder in anorthite is indicated by the presence of weak Si-O-Si antisymmetric stretc…
Abstract The unique properties of imogolite are closely related to its structure, which is a tube of 23–27 Å outer diameter and ∼10 Å inner diameter, with an AIOH outer surface and SiOH inner surface. Acid dispersions contain the long, positively-charged tubes as isolated units or small bundles, which form bulky gels…
Mullite ceramic, transparent in the infrared, was prepared by hot‐pressing and hot‐isostatically pressing starting materials derived from alkyloxides. A composition with 72.3 wt% Al 2 O 3 yielded transparent, submicrometer grain size bodies at 1630°C, whereas higher temperatures produced glass‐containing microstructur…
Diatom immigration rates were affected by changes in current patterns similar to those found around substrates in streams and were increased by changes in microhabitat characteristics similar to those autogenically generated during diatom community development. Diatom abundances on tiles exposed for 24 h, i.e., diatom…
RNase labeled with colloidal gold was used as a model for the present technique evolved for the light microscopic localization of gold-labeled substances in semithin resin-embedded sections. Tissue sections placed on glass slides were treated with the gold-enzyme complex and subsequently exposed to a photographic deve…
J Mort and G Pfister (eds) 1982 Chichester: John Wiley xi + 336 pp price £37.30 There have been many treatments of organic semiconductors but this one is to be specially welcomed. It appears in an explosive and bewildering era of intense interest in the electrical behaviour of organic and, particularly, polymeric mate…
A recently introduced mean field theory of phase behavior in polymer/copolymer systems is extended to random copolymer/copolymer systems. Miscibility in these systems does not require any specific interaction but rather a “repulsion” between the different covalently bonded monomers of the copolymers. Conversely, immis…
In the present work, a continuation of others, there is studied the variation of the pH, and likewise the concentration of the ions Ca (II) and SO4 (II) of the means (filtered potable water) in which there have been submerged the test tube series of mortar (1:3) made with an industrial Portland cement of high initial…
A bibliographical study is carried out of the sulphates which may be present in the clinker and Portland cement, as likewise the effects of the aeration and temperature on the setting. This work is a prior phase of a wide experimental investigation carried out in the IETCC, on anomalies or setting and phenomena of "lu…
The final step in the creation of a system of simulation of the drying and purification of the air, yield answer when we attempt to produce determined conditions with it. In this article are gathered the different aspects to be borne in mind in such an evaluation efficiency of the drying and purification of the air, y…
This information paper deals with the subject treated in the mentioned meeting, the third of those celebrated by the Committee. This meeting was not previously programmed and had a character merely informative. Many questions related to the Scientific Program were treated in the meeting and a final proposal was prepar…