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The study of anharmonic effects in crystals has received considerable attention in the last few years. As a result of this it has been shown that many properties can be understood by expanding the interatomic potential and keeping only the lowest-order terms in the anharmonicity. The theory of thermal expansion, elast…
The fluorescence of a number of Bi3+ -activated phosphors is reported. Only host lattices containing a sublattice of large, trivalent cations are used, so that charge compensation of the activator is superfluous. The position of the broad emission band of these phosphors depends strongly on the host lattice and is fou…
A new electrooptic effect in certain classes of nematic liquid crystals is presented. The effect has been termed "dynamic scattering" because scattering centers are produced in the transparent, anisotropic medium due to the disruptive effects of ions in transit. The ions can be produced by field assisted dissociation…
Abstract not Available.
Abstract
Abstract The cross‐linking of poly [2.2‐propane‐bis‐(4‐phenyl carbonate)] by heating in a continuously evacuated system has been examined at various temperatures (295‐382°C). The effect of time and temperature on the viscosity of the polymer and the gel content is discussed.
Received 2 October 1967DOI:https://doi.org/10.1103/PhysRevLett.19.1423©1967 American Physical Society
Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation G. Blasse, A. Bril; Hypersensitivity of the 5D—7F2 Transition of Trivalent Europium in the Garnet…
The infrared spectrum of cyclopentene has been recorded in the range 18–300 cm−1. Two series of thirteen and nine Q branches, respectively, were observed, both of which arise from the strongly anharmonic energy levels of the B1 ring-puckering vibration. The longer, more intense series is assigned to molecules in the g…
The fluorescence of a number of new Ce3+-activated phosphors is described and discussed. Only host lattices with a sublattice consisting of trivalent lanthanide ions are used to avoid charge compensation of the Ce3+ ion. Usually the Ce3+ emission is in the near-ultraviolet region. Y3Al5O12–Ce and SrY2O4–Ce, however, s…
Measurements have been made of the Auger electron yield from polycrystalline Mo targets bombarded by mass-selected beams of ${\mathrm{Ar}}^{+}$ and ${\mathrm{He}}^{+}$ ions at normal incidence. The yields were measured for incident-ion kinetic energies of 50-400 eV. The experiments were conducted in ultrahigh vacuum t…
The optical absorption spectra of ZnO:${\mathrm{Ni}}^{2+}$ and ZnO:${\mathrm{Co}}^{2+}$ have been studied in the visible region, at temperatures from 7\ifmmode^\circ\else\textdegree\fi{}K up. From correlation with lattice phonon energies, evidence has been found for the assignment of much of the band structure to vibr…
Magnetic susceptibility, paramagnetic resonance, and antiferromagnetic resonance have been measured in MnTi${\mathrm{O}}_{3}$, FeTi${\mathrm{O}}_{3}$, CoTi${\mathrm{O}}_{3}$, and NiTi${\mathrm{O}}_{3}$. N\'eel temperatures ${T}_{N}$ of 65, 56, 37, and 23\ifmmode\pm\else\textpm\fi{}2\ifmmode^\circ\else\textdegree\fi{}K…
The optical-absorption coefficients for polarized light have been measured for single-domain crystals of $n$-type BaTi${\mathrm{O}}_{3}$. The measurements were made over a wavelength range from approximately 0.4 to 12 \ensuremath{\mu}, and over a temperature range from 26 to 130\ifmmode^\circ\else\textdegree\fi{}C. Th…
It is pointed out that a simple, localized-electron antiferromagnet having one electron per localized orbital interacting via 180\ifmmode^\circ\else\textdegree\fi{} superexchange with similar orbitals on $z$ near-neighbor cations via an overlap integral $\ensuremath{\Delta}$ has a N\'eel temperature $k{T}_{n}\ensurema…
Two series of manganate phases have been prepared and their magnetic properties measured. The first series consists, in addition to CaMn${\mathrm{O}}_{3}$, of three phases having layered structures. In these, tetravalent magnanese ions are contained in single or multiple perovskite layers which are separated from each…
Abstract The critical sizes of particles of magnetic material with high uniaxial anisotropy are calculated by equating the energies in the single and multi-domain states. Exact calculations are presented of the variation of critical size with shape for a rectangular particle, and the variation of critical size in an…
Abstract Cotton print cloth was treated with a solution of formaldehyde in concentrated orthophosphoric acid (a strong cellulose swelling agent). The treatment produces a crosslinked cotton with extremely high wet wrinkle recovery and moisture absorptivity, and very low dry wrinkle recovery. The variations in physical…
Abstract An aspen 4‐ O ‐methylglucuronoxylan was grafted with poly(sodium acrylate) (PSA) in 3.4 N NaOH at 25–30°C. with the use of a persulfate–thiosulfate redox initiator system. The formation of a true graft copolymer was indicated by fractional precipitation and light‐scattering studies, physical mixtures of the t…
Article The crystal structure and refinement of ferrimagnetic barium ferrite, BaFe12O19 was published on December 1, 1967 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 125, issue 1-6).