Materials Literature
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According to Herpin’s theorem, a symmetrical thin-film combination is equivalent, at one wavelength, to a single film, characterized by an equivalent index and equivalent thickness. If a large number of identical nonabsorbing thin-film combinations are combined, the resulting periodically stratified medium acts as a b…
Die vorliegende Arbeit beschäftigt sich mit der Nachbildung der halbleitenden Elemente der vierten Hauptgruppe 1 des periodischen Systems (Diamant, Si, Ge, graues Sn) durch bisher nicht als Halbleiter bekannte Verbindungen von Elementen der dritten Hauptgruppe (Al, Ga, In) mit Elementen der fünften Hauptgruppe (P, As,…
Summary A theory of work-hardening is put forward ; the salient points are as follows. There are two types of hardening ; the normal rapid hardening of cubic metals and the slower hardening characteristic of hexagonal crystals and cubic metals under conditions of easy glide. A quantitative theory of the rapid hardenin…
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The present position of our knowledge of antiferromagnetism, including ferrimagnetism, is reviewed, and some very interesting phenomena concerning the magnetic behaviour of certain ferrites and of pyrrhotite are described and explained.
Abstract The paramagnetic resonance spectrum of copper acetate is anomalous in that it resembles that of an ion of spin 1, and its intensity decreases as the temperature is lowered. The latter is correlated with the decreasing susceptibility found by Guha (1951). The following hypotheses are suggested: (1) the crysta…
Abstract Nach einer Definition des Begriffes Dioxolan wird das Polymerisationsverhalten dieser Verbindungen, soweit sie durch eine oder mehrere, semicyclisch gebundene Doppelbindungen charakterisiert sind, besprochen. An Beispielen ein‐ und zweifach ungesättigter Vertreter wird gezeigt, daß die Polymerisation als kryp…
In this paper the theories of superexchange interaction developed by Kramers and Anderson have been more generally reformalized by means of the well-known vector model. The formulation can also be applied to the problem of molecular structure in which a consideration of the various orbital configurations of electrons…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGravimetric Determination of Thorium and Rare Earth Elements in Magnesium AlloysG. B. Wengert, R. C. Walker, M. F. Loucks, and V. A. StengerCite this: Anal. Chem. 1952, 24, 10, 1636–1638Publication Date (Print):October 1, 1952Publication History Published online1 May 2002Pub…
Barium sulfide has been prepared in a form suitable as a cathode emitter as well as in the form of compressed pills. It has a work function of 2.1 ev with a wide variation possible in activation. The most active materials had an emission at temperatures of 900°K and greater comparable to that from pure BaO. Pure nicke…
Laboratory data are presented relating to the spontaneous cracking and embrittlement of steel alloys under environmental and stress conditions pertinent to sour gas condensate wells. It has been shown that cracking can occur in simple aqueous hydrogen sulfide solutions and is an effect related to stress corrosion crac…
Abstract Thermally contracted collagen, when swollen in appropriate media, obeys rubber elasticity theory. On the basis of the measurements which were made, it was possible to establish that the material behaves as if it were a network polymer crosslinked by covalent bonds. However, the chemical nature of these crossl…
Abstract Durch Umsatz von KO 2 und CuO in O 2 ‐Atmosphäre wurde bei 400–450° C KCuO 2 als stahlblaue, unmagnetische Verbindung erhalten. Die Substanz zeigt ein charakteristisches Röntgendiagramm; sie zersetzt sich mit verdünnten Säuren unter O 2 ‐Entwicklung und Bildung von Cu(II)‐Salzen. Thermisch zersetzt sie sich o…
The reactions to form RDX and HMX in Bachmann-type mixtures are comparable in respect of optimum nitric acid concentrations and in the fact that optimal amounts of acetic anhydride and ammonium nitrate are necessary for maximum yields of either explosive. The activation energies for formation of RDX and HMX were also…
Abstract Die Verwendung von Kunststoffen hat in den letzten Jahren im Apparatebau und in der chemischen Industrie ständig an Bedeutung gewonnen. Es ist deshalb wichtig, daß man sich einen Überblick über die Chemikalienbeständigkeit dieser Stoffe verschafft. Es werden der Verlauf und die verschiedenen Arten der Chemika…
Cadmiumchlorid und Lithiumboranat reagieren in atherischem Medium bei 0° miteinander unter Bildung eines Cadmiumboranats, Cd(BH 4 ) 2 . das schon bei Zimmertemperatur langsam in die Elemente zerfallt. Als Zwischenstufe der Umsetzung tritt ein Chlorcadmiumboranat, CdCl(BH 4 ), auf.
An analysis is made of the distribution of π-electrons in the crystal of boron nitride. The insulating character of this substance is shown by the fact that these electrons completely occupy one band, of width approximately 2.4 eV, separated from the next higher band by a gap of about 4.6 eV. The density of states in…