Materials Literature
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A Taylor series expansion of the intermediate coupling energy levels for Nd3+ and Er3+ was calculated. New energy levels can be calculated without rediagonalizing the matrix. A calculation for NdCl3 is discussed as an example.
Abstraft As a part of a detailed study of the structures and crystal chemistry of the aluminum silicate minerals the crystal structure of andalusite, Al 2 SiO 5 , has been refined. Twelve cycles of least-squares refinement on the IBM 704 computer reduced the disagreement factor, R , for 354 hkl reflections from an ini…
Im ersten Teil der vorliegenden Arbeit werden die theoretischen Grundlagen für die Bestimmung des Fernordnungsgrades nematischer kristallinflüssiger Schmelzen aus Messungen der diamagnetischen Suszeptibilitäten, der Brechungsindizes, des Dichroismus und der Protonenresonanzen behandelt. Im zweiten Teil werden diese Me…
The infra-red spectra of layer structures synthesized under controlled high-temperature, high-pressure conditions in sealed noble-metal systems have been examined in the region 400–5000 cm −1 (25–2 μ ). By complete replacement of an ion, e.g., Mg 2+ by Ni 2+ or Fe 2+ , Al 3+ by Ga 3+ or Fe 3+ , and Si 4+ by Ge 4+ it w…
The electron spin resonance of one of the defects produced by fast neutron irradiation of crystalline quartz is analyzed. The g tensor and hyperfine tensors deduced from these results imply that the defect electron is in a nonbonding tetrahedral hybrid orbital on a silicon. It is suggested that the instability of the…
Samples of Ca 2 SiO 4 were prepared by three different methods. These samples were examined by differential thermal analysis, high‐temperature X‐ray diffraction, and air quenching of pellets. It was found that the β modification, during cooling, converted completely and rapidly to the γ modification and “dusted” only…
Article A handbook of lattice spacings and structures of metals and alloys. was published on August 1, 1961 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 115, issue 3-4).
Ceramic dielectrics capable of field-enforced antiferroelectric-to-ferroelectric transitions from below -60°C to over 100°C have been made. The transition manifests itself by a D/E hysteresis figure with a linear central region and loops showing saturation on either end. Previously studied materials have exhibited thi…
This paper is concerned with the effects of orientation on the combinatorial term g for the number of ways to pack together Nx linear polymers (x mers). Accordingly g is evaluated as a function of the number of molecules in each permitted direction for the case of straight rigid rods. The permitted directions can be c…
The behavior of a stream of electrons penetrating a solid target is studied with a view to determining the proportion which return to the surface and pass back into space. Two existing theories (diffusion and large-angle single elastic scattering) are adapted to this end. These theories predominate for high and low at…
Diamond growth occurs at high temperatures and pressures in the presence of certain molten metals which serve as solvent catalysts. The zones of pressure and temperature in which diamond growth occurs have been determined for a number of metals. These zones are bounded on the low-temperature side by the melting point…
It is shown that the Debye-Scherrer method can be used successfully on an x-ray spectrogoniometer by removing the bisecting mechanism. Complete profiles of the diffraction lines have been recorded and the center of gravity (CG) determined with an accuracy of ±0.005°2θ. Monochromated CuKα1 radiation was employed and th…
A surface-active aqueous solution was foamed up a glass column, removed, collapsed, and returned as down-coming liquid to drain countercurrently against the rising foam. This deliberate refluxing action greatly increased the degree of separation of the surfactant over that obtainable without reflux. The effects of alt…
Single crystals of NaCl, KCl, and KBr were grown from the melt in an oxygen atmosphere, and their optical absorption, fluorescence excitation, and fluorescence emission spectra were measured at 300\ifmmode^\circ\else\textdegree\fi{}, 77\ifmmode^\circ\else\textdegree\fi{}, and 4.2\ifmmode^\circ\else\textdegree\fi{}K. T…
Abstract The writer's original views (1942) on the polymorphism of calcium carbide are upheld in his discussion of a different phase scheme recently proposed by B ORCHERT and R ÖDER . The lattice constant of the cubic phase, IV, is newly determined as 5,880 ± 0,005 Å at 477 ± 2 °C, and its transition temperature is 45…
The preparation and properties of UB and ThB/sub 4/, and to some extent of UB/sub 2/ and ThB/sub 6/, were studied in view of the possible application of these materials as nuclear fuels. Previous work is briefly reviewed, with particular reference to six reported methods of preparation. The compouirds were prepared by…
Abstract The consumption of various p -phenylenediamines during the oxidation of natural rubber vulcanizates has been investigated in the temperature range of 80–120° C. Oxygen absorption was used to follow the oxidation. Diaryl- p -phenylenediamines were consumed mainly in a termination reaction during the constant r…
High-purity zinc crystals were grown from the melt by the soft mold technique, and bent in such a way that [01̄10] was parallel to the bending axis and the [211̄0] slip direction enclosed approximately 45° with the bending radius. A dislocation etching technique was developed, which reveals the edge dislocations intro…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNotes- Ring-Expansion of Pyrrole and IndoleGerhard Closs and Gerald SchwartzCite this: J. Org. Chem. 1961, 26, 7, 2609Publication Date (Print):July 1, 1961Publication History Published online5 March 2003Published inissue 1 July 1961https://pubs.acs.org/doi/10.1021/jo01351a65…
Abstract As the accelerating effect of water in the crosslinking reaction of rubber in natural latex by γ‐irradiation was assumed to stem from the decomposition of water into radicals by γ‐irradiation, more effective reagents were sought among the organic halides which have greater G values for radical formation by γ‐…