Materials Literature
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Les auteurs montrent que l'on peut obtenir un quart d'onde quasi achromatique en juxtaposant deux lames cristallines, l'une demi-onde, l'autre quart d'onde pour la région moyenne à achromatiser. L'angle des lignes neutres des deux lames étant de 60 degrés — β (β un angle inférieur à 3,5 degrés dépendant de la nature d…
A class of new phosphors of great technical importance is described, which enables white light to be obtained in fluorescent lamps from a single chemical compound. The new materials are alkaline earth halophosphates activated with antimony and manganese. Luminescent properties are discussed as a function of compositio…
A. F. Wells, Discuss. Faraday Soc., 1949, 5, 197 DOI: 10.1039/DF9490500197
The first page of this article is displayed as the abstract.
Abstract Nicht nur niedermolekulare, auch hochmolekulare Verbindungen mit benachbarten, cis‐ständigen Hydroxylgruppen bilden Komplexe mit Borsäure oder Boraten; unter geeigneten Bedingungen entstchen Koordinationsverbindungen aus einem Molekül Borsäure und zwei Diolgruppen. Diese Didiol‐Borsäure‐Komplexe können als Ha…
"Klockmann's Lehrbuch der Mineralogie." Geologiska Föreningen i Stockholm Förhandlingar, 71(1), p. 184
C. H. Bamford and M. J. S. Dewar, J. Chem. Soc., 1949, 2877 DOI: 10.1039/JR9490002877
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAnalogs of Aspergillic Acid. I. The Tautomerism of the Hydroxypyridine-N-oxidesElliott. ShawCite this: J. Am. Chem. Soc. 1949, 71, 1, 67–70Publication Date (Print):January 1, 1949Publication History Published online1 May 2002Published inissue 1 January 1949https://doi.org/10…
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When Rayleigh's law for small hysteresis loops is interpreted in terms of the elementary process of domain wall displacement, its generalization to include effects of stress becomes possible. In this way theoretical formulas have been derived for the behavior of a soft iron or steel specimen which is first put into a…
W. K. Burton and N. Cabrera, Discuss. Faraday Soc., 1949, 5, 33 DOI: 10.1039/DF9490500033
C. Eaborn, J. Chem. Soc., 1949, 2755 DOI: 10.1039/JR9490002755
Abstract Studies of strategic mineral deposits in the major domestic pegmatite districts by the U. S. Geological Survey from 1939 to 1945, primarily for the purpose of increasing production of mica, beryllium, lithium, and tantalum minerals, resulted in the clarification of many problems related to the general. featur…
In view of mis-statements made in the literature, the origin of the refractive index in electron optics is discussed in some detail, and the uniqueness of an expression previously given is demonstrated. On this basis, some general properties of electron optics are investigated. A relation between ray direction and wav…
The resolving power of the electron microscope and the contrast in the image are calculated for different conditions of focusing, illumination and aperture. These conditions can change the limit of resolution by a factor of about 3. The contrast in the image of an atom is appreciably increased by defocusing and spheri…
F. C. Frank, Discuss. Faraday Soc., 1949, 5, 48 DOI: 10.1039/DF9490500048
Abstract The problem of metallic conduction at high frequencies and low temperatures, recently discussed by Pippard, is reformulated using the general methods of the theory of metals, and exact solutions are obtained which are valid for all frequencies and temperatures. It is shown that, for large values of the free p…
In certain exponential absorption experiments, notably measurements of cross sections by transmission, it is important to achieve minimum statistical error in a limited time or to minimize the counting time required to measure the absorption coefficient with a preassigned accuracy. The conditions required to attain th…
A bstract A study has been made of the transmittance of near‐infrared energy by a number of binary glasses. Of the systems studied, the lithia‐silica and lead oxide‐silica glasses were found to have the highest transmittance of energy in the range of wave lengths from 3.0 to 5.0 microns. The transmittance of lithia‐si…