Materials Literature
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The intensities of low-angle neutron-diffraction peaks have been measured for the antiferromagnetic solids MnO, α-MnS, and NiO. From the reduced intensities of the (111) magnetic peaks the following covalency parameters have been derived: Aσ2 + 2Aπ2 + As2 = 3.5% (MnO); 7.6% (α-MnS); Aσ2 + As2 = 3.8% (NiO).
The kinetics of the aragonite-calcite transformation were studied in aqueous solution to determine the factors involved in the process of calcite crystallization and the controlling diagenetic conditions for the aragonite-calcite transformation. The reaction involved the solution and equilibration of aragonite with th…
Crystallographic, magnetic, and electrical studies of the system La1−xSrxCoO3.00±0.01 for 0≤x≤0.5 give indirect evidence for the presence of chemical inhomogeneities separating strontium-free regions, where localized ``3d'' electrons occur at thermally excited high-spin Co3+ ions, from strontium-rich regions, where th…
Abstract Thermotropic mesomorphous phases such as occur in the melts of many organic substances are considered. Though mesomorphous melts were first observed by Reinitzer in 1888, fundamental structural problems regarding such melts have not, as yet, been completely solved. Part I of this article deals mainly with suc…
An account is given of a study of the dimensional changes of plain-knitted fabrics brought about by various relaxation treatments. A wide range of natural and synthetic-polymer fibres was encompassed. It was found that, for synthetic-fibre fabrics, dry tumbling at elevated temperatures causes higher levels of relaxati…
The theory of fine-particle magnets is based on the theorem that the state of lowest free energy of a ferromagnetic particle is one of uniform magnetization for particles of less than a certain critical size and one of nonuniform magnetization for larger particles. The theorem is inferred from several approximate calc…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanism of Calcium Carbonate Scale Deposition on Heat-Transfer SurfacesDavid Hasson, Mordecai Avriel, William Resnick, Tzvi Rozenman, and Shlomo WindreichCite this: Ind. Eng. Chem. Fundamen. 1968, 7, 1, 59–65Publication Date (Print):February 1, 1968Publication History Publ…
Numerous measurements of saturation magnetization of Fe and Ni are reported. Saturation magnetization is determined by consideration of all contributions in the change of magnetization in high magnetic fields, i.e., internal demagnetizing fields, homogeneous rotations, and paramagnetic terms. The value found for the a…
Mössbauer spectra of CoFe2O4 show that this spinel is not completely inverse and that the degree of inversion depends on the heat treatment of the material. The magnetic moments of the slowly cooled and the quenched material are 3.4 and 3.9 μB per unit chemical formula, respectively, and the Néel temperatures are 798°…
Received 21 November 1967DOI:https://doi.org/10.1103/PhysRevLett.20.209©1968 American Physical Society
The X-ray scattering produced by a distribution of two-dimensional lattices with preferred orientation, a problem which arises e.g. in the study of anisotropic structures of non-graphitic C atoms, is given a rigorous theoretical treatment for infinite and perfect lattices and approximations are given for finite and im…
Takagi's theory is used to calculate the propagation of X-rays in perfect and nearly perfect crystals. In the general case, the equations have to be solved on a computer. The principle of the calculation is given. It has been applied to the case where an incident plane wave is collimated by a slit. The separation of w…
The Reciprocity Theorem of scattering theory is shown to hold generally for electrons scattered elastically in an absorbing medium, and also for inelastically scattered electrons, to a certain approximation. Two scattering symmetry conditions are defined by applying the theorem to crystals having mirror symmetry paral…
Abstract A new model is proposed to describe the large recoverable extensions which can be observed with high polymers below their glass transition points. The model consists of a Hookean spring in series with an Eyring dashpot and rubber elasticity spring in parallel. Conventional stress-strain curves for cellulose n…
In the analysis of spin structures a `natural' point of view looks for the set of symmetry operations which leave the magnetic structure invariant and has led to the development of magnetic or Shubnikov groups. A second point of view presented here simply asks for the transformation properties of a magnetic structure…
A binuclear ion ([NH(3))5RuN(2)Ru(NH(3))(5)](5)+ is formed by the direct reaction of N(2) with an aqueous solution of (NH(3))(5)RuOH(2)(2+) at room temperature. The binuclear ion is also formed by the reversible reaction of (NH(3))5RuOH(2)(2+) with (NH(3))(5)RuN(2)(2+). Solid [(NH(3))(5)RuN(2)Ru(NH(3))(5)] (BF(4))(4)…
The infrared absorption spectrum of KH2PO4, KD2PO4, and KH2AsO4 single crystals has been measured from 3000-1000 cm−1 over a temperature range from 20°-300°K. Three broad absorptions are found at 2670, 2360, and 1720 cm−1 which are associated with the hydrogen bonds. The two upper frequencies are stronger for light po…
Mössbauer spectra of naturally occurring mineral chalcopyrite have been studied over a temperature range 300°–448°K. The spectra showed a typical pattern of six absorption lines due to the internal magnetic field. The Q.S. have values which are independent of temperature whereas the magnitudes of the internal magnetic…
Measurements of the galvanomagnetic properties of single-crystal graphite were made at 4.2\ifmmode^\circ\else\textdegree\fi{}K in pulsed magnetic fields up to 160 kG. With the magnetic field parallel to the $c$ axis, the transverse magnetoresistance is approximately proportional to the magnetic field strength, and the…
Absolute-reflectance measurements of single-crystal Re${\mathrm{O}}_{3}$ in the spectral range 0.2-22 eV are analyzed by Kramers-Kronig relations to give the real and imaginary parts of the dielectric constants. The dielectric constant is characteristic of free-electron behavior below the sharp plasma edge at 2.1 eV,…