Materials Literature
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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…
This paper analyzes the idealized geometry of a bent yarn. Expressions are derived for the cal culation of local fiber tensile strain, average strain in the helix half loop, motion of the fibers during bending of the yarn, changes in local helix angles, and fiber curvatures at the bend. The relationships between the g…
The Bloch (tight-binding) approximation is applied to a study of graphite The Mean energy per atom and the internuclear distance are calculated in good agreement with experiment. Previous accounts are extended by including certain overlap imegrals and by dealing with a set of parallel layer planes instead of only one…
The tl:erma.l properties of polytetra~~oro e thyl ene (Teflon ) . samples were investigated, uStng an ad l abatJc~vacuum calonmeter. Ihe effect of the annealll1g and quenchtng processes on the heat capacity of a mold ed T eflon sample was studied. The heat-capacity data were used to compute the heat capacity, enthalpy…
Recent experiments have demonstrated the feasibility of observing nuclear electric quadrupole interactions of widely varying magnitudes in solids. While these effects can often be observed in powdered samples, the most complete information is obtainable from the Zeeman pattern of a single crystal. To facilitate interp…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystallographic Data. 61. dl-Mandelic AcidH. A. RoseCite this: Anal. Chem. 1952, 24, 10, 1680–1681Publication Date (Print):October 1, 1952Publication History Published online1 May 2002Published inissue 1 October 1952https://pubs.acs.org/doi/10.1021/ac60070a065https://doi.or…
The projection and transmission methods of diffraction image formation with electrons are discussed in relation to their practical application.The significance of the two methods as limiting cases of one general method is shown. Analysis shows that the projection method is limited in a practical sense by the combinati…
Extractamos en las páginas que siguen algunas notas recientes sobre la fabricación de áridos ligeros para hormigón, a base de pizarras y escorias esponjadas, vermiculita, etc. También se indican, creemos que, por vez primera en idioma español, algunas particularidades relativas a la fabricación del material ligero de…
Especialmente enviado para Útimos Avances, desde Venezuela, tenemos el gusto de presentar el trabajo del Sr. Capella Canals, en el que se muestra el diseño de un aparato sencillo para medidas de permeabilidad en polvo de cemento, es decir, para determinaciones de superficie específica. Dada la dificultad de lograr en…
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The crystal structure of NaZn_(13) and of several homologous compounds AB_(13) was reported by Ketelaar and by Zintl & Hauke to be based on space group O_h^6-Fm3c, with 8 :Na in 8(a): ¼, ¼:, ¼; ... ; 8 Zn_I in 8(b): 0, 0, 0; .... ; and 96 Zn_(II) in 96(i): 0, y, z; ... . Approximate values were reported for the pa…
The formulae are given for the Fourier transforms of a number of helical structures; namely, a thin helical wire, a set of identical atoms spaced at regular intervals on a helix, and the general case of a group of atoms repeated by the operation of a non-integer screw. General predictions are made concerning the inten…
Abstract The minerals in acid-insoluble residues, 2 microns and less in diameter, from 27 limestones and dolomites, ranging in age from Cambrian to Recent, both marine and non-marine in origin were determined qualitatively. Quartz is widespread and abundant. Illite is the dominant clay mineral in both marine and non-m…