Materials Literature
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Following an earlier paper based on the Morse potential, the analysis of the thermal properties of a linear chain is now extended to cover an interatomic potential of arbitrary form. The Lennard-Jones potential is taken as an example and the results for the thermal expansion coefficient are compared with experimental…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermodynamics of Crystallization in High Polymers: Natural Rubber1,2Donald E. Roberts and Leo MandelkernCite this: J. Am. Chem. Soc. 1955, 77, 3, 781–786Publication Date (Print):February 1, 1955Publication History Published online1 May 2002Published inissue 1 February 1955h…
Abstract The hydrated Mg-vermiculite lattice contains double sheets of water molecules interleaved with silicate layers. In the fully hydrated condition, each water sheet is arranged in a regular hexagonal pattern and the interlayer cations are located midway between water sheets in octahedral coordination. Release of…
Data are presented on the changes in the room‐temperature refractive index and density of a borosilicate crown glass produced by different heat‐treatments. Measurements on a large number of samples with widely varying thermal history show that the refractive index is a single‐valued function of the density. The increa…
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Las piezas aligeradas presentan una serie de propiedades: densidad, aislamiento térmico, etc. Que determina siempre, siempre que no se precisen, simultáneamente, grandes resistencias. Su preparación, tal como se indica en este artículo, carece de dificultades.
En un secadero túnel, con aire introducido por presión y con circulación cíclica, se consiguen las mayores ventajas prácticas. Se reduce el peligro de la condensación de humedad, evitándose, por consiguiente, el reblandecimiento de los ladrillos y la formación de grietas durante el secado.
Se discute, en este artículo, la construcción de un secadero, unido directamente a un horno túnel, sin puertas intermedias. Se presta atención al problema de la recuperación de calor y a la dificultad de controlar el flujo de gases desde el horno al secadero.
El tratamiento al autoclave ofrece interesantes oportunidades para la preparación de productos de hormigón, a partir de una gran variedad de materias primas.
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Abstract On the basis of simple assumptions, equations are derived for predicting the specific volume‐temperature‐molecular weight ( v ‐ T ‐ M ) relationships for a homologous series of polymers from the v ‐ T curves for the monomer and the polymer of infinite molecular weight. Analogous v ‐ T ‐ρ relationships (where…
Using the method of generating function, we have discussed the shape of the absorption band and the probability for non-radiative transition of a trapped electron in insulating or semiconducting crystal, especially their temperature dependence. We have thereby chosen a model for the vibrational motion of the lattice a…
Abstract A group-theoretical treatment of the spatial symmetry of two-dimensional graphite leads to a classification of the one-electron eigenstates. The method of idempotent operators is used to derive Bloch orbitals for the crystal valence bands as linear combinations of the atomic orbitals 2px, 2py and 2s. The func…
Abstract Isobars for the adsorption of O2, H2 and CO on evaporated films of Rh, Mo, W and Fe, of Ch and CO on Ta, Pt and Pd, and of O2 on Cu, Al and Zn have been obtained. On Rh, Mo and W the rapid adsorption of O2 and H2 at -183° C results in formation of monolayers with one atom per surface atom. On Ta, Pt, Pd, Cu,…
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.
The influence of an addition of chromium on the thermal expansion coefficient of the alloys of iron, cobalt and nickel has been determined. It has been found that in the quaternary system of iron, cobalt, nickel and chromium, there are two valleys of the expansion coefficient, one of which originates in the compositio…
The combination of high electrical resistivity and useful magnetic properties has caused ferrites to become increasingly important as high-frequency core materials. A description of the general structural and saturation magnetization properties of the more simple ferrites, and of their preparation, is followed by a br…
Abstract In some circumstances tin surfaces remain unattacked by solutions of ammonia. Factors leading to a low probability of the beginning of corrosion are: reduction in temperature of the solution, the quality of the metal surface, especially as it affects the formation of a protective oxide film in air, and also e…
(1955). Investigations Concerning Formation, Preservation and Utilization of Carotene. Acta Agriculturae Scandinavica: Vol. 5, No. 1, pp. 113-184.