Materials Literature
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Abstract Aus SiCl 4 und flüssigem NH 3 dargestelltes Si(NH) 2 wird bei p NH3 = 50 Torr abgebaut. Folgende Abbaureihe wurde sichergestellt: magnified image Außer dem hexagonal kristallisierenden α‐Si 3 N 4 2 sind alle Verbindungen röntgenamorph und sehr feuchtigkeitsempfindlich. Wahrscheinlich liegen Hochpolymere vor,…
The magnetization of single crystals and of polycrystals of a number of materials has been investigated at temperatures from 1. 3 to 300 °K, in fields up to 12,500 oersteds. Measurements were made on single crystals of LiMnPO4 (orthorhombic), Fe 3(PO4)2.4H2O (monoclinic), and HoFeO 3 (orthorhombic) ; polycrystalline m…
H. B. Henbest and B. Nicholls, J. Chem. Soc., 1959, 221 DOI: 10.1039/JR9590000221
After a brief reference to the physical basis for a tetragonal distortion (c/a > 1) of an octahedral anion interstice which is occupied by a cation with outer-electron configuration 3d4, the crystallographic properties of several Mn3+-containing oxides are given to illustrate the significance of this effect for determ…
Abstract Azulen‐aldehyde‐(1) bzw. ‐(3) lassen sich nach dem Verfahren von V ILSMEIER darstellen. Sie sind reaktionsträger als aromatische Aldehyde. Die Aldehydgruppe läßt sich durch Reduktion nach H UANG ‐M INLON in die Methylgruppe überführen. Die dabei eintretenden spektralen Verschiebungen werden diskutiert. An ein…
Single crystals of the compound silicon hexaboride have been prepared. Laue, rotation, and Weissenberg photographs indicate an orthorhombic cell with lattice parameters a = 14.39 ± 0.01 , b = 18.27 ± 0.01 , and c = 9.88 ± 0.01 A å . The pycnometer density is 2.43 g/cm 3 . The average electrical resistivity of single c…
R. Bonnett, V. M. Clark, A. Giddey and A. Todd, J. Chem. Soc., 1959, 2087 DOI: 10.1039/JR9590002087
The systems germanium-graphite and germanium-silicon-carbon have been studied. Several gaseous molecules containing Ge, Si, and/or C were observed and their dissociation energies determined from measured partial pressures. A general picture of the dissociation energies of di-, tri-, and tetraatomic intergroup IVB mole…
Abstract Twenty‐two α‐olefin monomers with varying degrees and types of branching in the lateral group have been polymerized and the polymers characterized. In general, the closer the branching in the side chain is to the polyethylene trunk, the higher the degree of crystallinity and the crystalline melting point. The…
L'auteur développe une théorie élémentaire des couplages entre domaines ferromagnétiques à cycles rectangulaires, basée sur l'étude détaillée des propriétés de couples de deux domaines : il prévoit ainsi des effets théoriques nouveaux et notamment celui de bascule. Il s'agit d'une variation positive ou négative de l'a…
The growth of anodically formed barrier oxide films on aluminum has been followed by weight, capacitance, and rate measurements. The increase of film thickness at constant voltage has been calculated and compared to the values obtained by optical measurements. The results have been shown to obey the law .
L'aimantation à saturation absolue, les paramètres de la maille et les intensités des raies Debye-Scherrer ont été étudiés dans les composés BaO, (6-x) Fe2O3, xM2O3 où M = Al, Ga, Cr. On en déduit la répartition préférentielle des atomes M sur les sites cristallographiques 2a, 2b, 4f1, 4f2 et 12k du groupe P6/mmc. La…
Abstract Transitions in polymers have been studied with the use of a differential expansion apparatus modified from a design described by K. L. Floyd. Materials ranging from uncured, soft rubbers to hard, waxy solids have been studied from above room temperature down to liquid air temperatures. Both the first‐order tr…
B. N. Figgis and R. S. Nyholm, J. Chem. Soc., 1959, 338 DOI: 10.1039/JR9590000338
Abstract Die Anregung von Metallelektronen durch Primärelektronen mittlerer Energie wird mit der Diracschen Störungsrechnung in Einelektronennäherung untersucht. Für Prozesse ohne Quasiimpuls‐Austausch mit dem Gitter (ξ = 0‐Prozesse) wird die Anregungsfunktion streng abgeleitet. Die für ≠ 0‐Prozesse erhaltenen Ausdrüc…
Abstract not Available.
Peculiar changes in the ferroelectric hysteresis loops of single crystals of triglycine sulfate result when the crystals are subjected to ionizing radiations (x-rays and electrons). Fully polarized crystals develop hysteresis loops biased along the field axis while partially polarized crystals develop double-loop patt…
Abstract The production of crosslinks and of sites for grafting in solid high polymers can be achieved by hydrogen abstraction. This hydrogen abstraction reaction can be carried out by means of far ultraviolet light (200–300 mμ). The rate of the reaction is tremendously increased if certain sensitizers are incorporate…
Single crystals of polyethylene were examined electron-microscopically with special precautions to avoid damage due to the electron beam. A variety of unexpected beam-sensitive features were observed. They can be classified as (1) moirés. (2) morphological features. In connection with (1) the general principles of moi…
Abstract Bei der Kristallisation von Niederdruckpolyäthylen aus Lösung in dünnsten Filmenerhält man lamellen‐bzw.fibrillenartige Einkristalle, in denen nach Elektronenbeugungsmessungen die Molekülketten senkrecht zur Lamellenbene bzw. zur Längsrichtung der Fibrillen stehen. Die Moleküle müssen also gefaltet sein. Bei…