Materials Literature
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Summary Uvarovite and its relationships with grossular and andradite have been studied in order to understand better the geochemistry of uvarovite. Synthese have been carried out under both dry and hydrothermal conditions; a solid solution with grossular was obtained under both conditions, but with andradite only unde…
The elastic displacement of screw dislocations bounding the lamellar grains is of the correct order of magnitude to account for the observed elasticity of reactor grade graphite. The change of elastic modulus on irradiation cannot be explained in terms of the pinning of these or of other dislocations by the clusters o…
Summary The transformation of manganite during heating has been studied by single crystal X-ray diffraction methods. It is observed that manganite transforms into pyrolusite keeping its original axial directions parallel to those of the transformed phase. Pyrolusite then transforms into Mn 2 O 3 with its [001] ‖ [110]…
An experimental investigation of the effects of temperature and grain size on the tensile properties of high purity molybdenum showed that transitions from ductile to brittle behaviour occur with both decreasing temperature and increasing grain size. Based on the assumed temperature-independence of the critical stress…
Magnetic structure of single crystal of Fe2As, which corresponds to C38 type of crystal structure, the same as that of Mn2Sb, has been determined by neutron diffraction method. The crystal is antiferromagnetic with the Néel temperature of approximately 50°C. A series of (00l)-type reflections at room temperature revea…
Infrared transmission of NiCr2O4 and MnCr2O4 powder was measured from 15 to 500 μ and at 100°–400°K. Four absorption peaks were discovered at ∼600, ∼500, ∼400, and ∼200 cm−1. The peak near 200 cm−1 of NiCr2O4 showed a shift with temperature which is apparently proportional to the change of c/a, while the width remaine…
The kinetics of formation at 900°C of the fcc γ phase have been studied metallographically in Alnico 8 alloys with Cu contents from 0.01 to 3.34 at. %. Increasing Cu content is found to increase the gamma-forming tendency. Selected two-phase specimens subjected to electron microprobe analysis showed a systematic deple…
A single parameter is suggested to account for the complicated stress and strain distributions in two-phase materials. Its existence requires verification from extensive experimental studies.
Abstract The distributions of short‐chain branching in some commercial low‐density polyethylenes have been investigated by measuring the degree of short‐chain branching of their fractionated samples. The results obtained on the fractions which were fractionated with respect to molecular weight showed that some polyeth…
Abstract A reinvestigation of the constitution of green and brown complex iron cyanides, often reputed to be Fe III Fe III (CN) 6 , has been undertaken. Infra‐red absorption spectrophotometry by means of which the valence state of iron in the [Fe(CN) 6 ] n− ‐ions may be identified, was used as main diagnostic tool. It…
The case of an elastic disturbance propagating in a nonhomogeneous bar of finite length is solved by using the principle of virtual work. The nonhomogeneity is prescribed as a continuously varying modulus of elasticity with position in the bar. The density is assumed constant. Numerical results are presented for a fin…
Abstract The oxygen atomic parameters in the crystal structure of Pb 3 O 4 were checked by neutron diffraction. The results obtained confirm the structure reported by B YSTRÖM and W ESTGREN .
Abstract The oxidation of three types of uranium dioxide (UO 2 ) material has been investigated in the 120—360° range. In UO 2 powders, of surface area greater than about 2 m. 2 /g., oxidation was diffusion‐controlled up to U 3 O 7 which oxidised to U 3 O 8 above about 240°. The activation energies were in the range 2…
Self-diffusion measurements have been made in the temperature range 1000°c to 1550°c in order to resolve some uncertainties arising from previously published data from several separate investigations covering various parts of this range. A normal Arrhenius type of temperature dependence has been found, indicating the…
Abstract Je nach der Vorpolarisation verändert sich die Lage des Ladungsnullpunktes (Verschwinden der Raumladung im Halbleiter) an einer Germaniumoberfläche zwischen 2 Extremwerten. Dies läβt sich auf einen Unterschied im Oxydationszustand der Oberfläche zurückführen, für die man einmal einen hydroxidartigen, das ande…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStable Carbonium Ions. IX.1 Methylbenzenonium Hexafluoroantimonates2George A. OlahCite this: J. Am. Chem. Soc. 1965, 87, 5, 1103–1108Publication Date (Print):March 1, 1965Publication History Published online1 May 2002Published inissue 1 March 1965https://pubs.acs.org/doi/10.…
The temperature dependence of the rate of growth of PbTiO 2 crystals from a PbO‐B 2 O 3 ‐TiO 2 glass was experimentally determined. The Brown‐Ginell equation describing the temperature dependence of the growth rate provided an excellent fit for the data. The activation energy for the growth of PbTiO 3 crystals was 34…
The absorption spectrum of anthracene single crystal was measured in the range from 3950 A to 4400 A, i.e., the long wave-length tail of A 1 g – B 2 u transition. For the change of temperature from -180°C to 80°C, the absorption increases markedly both for a- and b-polarized light. The contour in the absorption tail c…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMetal Chelates of Mercaptosuccinic and α,α'-Dimercaptosuccinic AcidsG. R. Lenz and A. E. MartellCite this: Inorg. Chem. 1965, 4, 3, 378–384Publication Date (Print):March 1, 1965Publication History Published online1 May 2002Published inissue 1 March 1965https://pubs.acs.org/d…
The solid solubility and order-disorder relations in the systems $$BaCO_{3}-SrCO_{3}, SrCO_{3}-CaCO_{3}$$, and were investigated at temperatures of from 400° to 1,000° C. with sufficient $$CO_{2}$$ pressure to prevent decomposition of any carbonates involved. A high-temperature X-ray furnace and cold-seal bombs were u…