Materials Literature
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We have measured self-diffusion along widely spaced edge dislocations in nickel. A surface-accumulation counting technique was used. The dislocations were arranged to be perpendicular to the surface which was counted and were pure edge in character. The diffusion measurements were carried out in the temperature range…
A high-temperature cluster series is derived for the partition function of an order-disorder-type hydrogen-bonded ferroelectric crystal, taking into account a simplified interaction between protons as well as the overlap of the protonic wave functions between the two sites in a hydrogen bond. The zero-order result is…
The magnetic structure of Fe${\mathrm{Sb}}_{2}$${\mathrm{O}}_{4}$ at 4.2\ifmmode^\circ\else\textdegree\fi{}K has been investigated by powder neutron-diffraction techniques. The spin arrangement is noncollinear, consisting of a combination of three different antiferromagnetic modes. The principal mode ($A$) is one in w…
The absorption spectra of large single crystals of Er2O3 observed at 10°, 80°, and 290°K were analyzed in the 2200–10 000-Å wavelength region. Over 600 transitions from all eight crystalline Stark levels of the ground 4I15/2 state to over 30 excited J manifolds of the Er3+ ion in C2 sites were assigned. In thick cryst…
The magnetic susceptibility of strontium titanate with and without charge carriers has been measured at 300, 78, and 4.2\ifmmode^\circ\else\textdegree\fi{}K. Insulating SrTi${\mathrm{O}}_{3}$ shows a magnetic moment, which is partly diamagnetic and partly (Van Vleck) paramagnetic. The free-carrier contribution is main…
A four-particle cluster approximation is worked out for the free energy of ferroelectric K${\mathrm{H}}_{2}$P${\mathrm{O}}_{4}$, taking into account the overlap of the protonic wave functions between the two sites in a hydrogen bond as well as short-range and long-range forces and a part of the proton-lattice interact…
Measurements of the magneto-optical rotatory dispersion (MORD) and magnetic circular dichroism (MCD) through the accessible charge-transfer bands of Fe(CN)63−, MnO4−, and CrO42− in the visible and ultraviolet are described and interpreted. The apparatus employed combines a superconducting solenoid furnishing maximum f…
The internal magnetic fields and isomer shifts of ${\mathrm{Fe}}^{57}$ nuclei in a number of iron-rich bcc binary alloy systems were measured by the M\"ossbauer technique. The added solute atoms Al, Si, Mn, Cr, or V give structure to the individual lines of the spectra indicating that their effects are quite localized…
The lowest $4f\ensuremath{\rightarrow}5d$ ultraviolet absorption band of eleven (Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb) of the fourteen trivalent rare-earth (RE) ions in host Ca${\mathrm{F}}_{2}$ crystals has been measured. The room temperature absorption cross section [${\mathrm{cm}}^{2}$] and half-width [${…
Abstract The chemorheology of crosslinked polyethylene disulfide, polyethylene tetrasulfide, and mixtures of these polymers with elemental sulfur is investigated. It is shown that stress decay in the disulfide polymer occurs by scission of the small quantities of higher polysulfide linkages present in the network. It…
Textural and compositional features of reaction products in the system kaolin–lime–water were examined by electron microscopy and electron diffraction. Electron micrographs of replicas of fracture surfaces of compacted mixtures and transmission electron micrographs of powdered compacts showed considerable attack of ka…
This is an overall study of the whole process of projectile penetration into soil. The governing differential equations for the soil target medium are developed using the equations of motion and the continuity condition. Constitutive relationships are derived from Mohr-Coulomb theory for a rigid plastic material and f…
Exchange-coupled F-centre pairs have been observed in neutron-irradiated magnesium oxide by paramagnetic resonance. Studies of the temperature dependence of the signal intensity indicate that the exchange energy J/k = 80 ± 10°K. The measured spin-Hamiltonian parameters are consistent with the pair of F centres being i…
Calculations of the diffraction contrast to be expected from spherical precipitates and prismatic dislocation loops are reported. If these defects lie close to a foil surface, the effect of the free surface on the image is important. In each case, there exists a certain critical strength of the defect, such that if th…
Abstract Auf Grund vielfach eigener Untersuchungen wird berichtet über: Bildungsbedingungen, Phasenbestände und Epitaxie‐Topotaxie‐Beziehungen von Schichten der atmosphärischen Korrosion, des Angriffs durch Industrieluft mit ihren vielfältigen Reagenzien, des Salzwasser‐, Heißwasser‐ und Heißdampfangriffs und der Hoch…
The thermal conductivity, electrical conductivity, and Seebeck coefficient of several specimens of SnTe have been measured between 100° and 500°K. The thermal conductivity is weakly dependent on both temperature and hole concentration. The total thermal conductivity is separated into an electronic and a lattice therma…
Abstract Using X-ray techniques, the orientation distributions of crystal planes in laboratory prepared and naturally occurring aggregates were measured. A small specimen was mounted on the axis of a goniometer and the diffracted intensity measured as the specimen was rotated. Mo radiation was used to reduce the absor…
Abstract Die thermische Darstellung der Verbindungen 2BaO · P 2 O 5 · B 2 O 3 und 2BaO · As 2 O 5 · B 2 O 3 wird beschrieben. Sie sind isotyp mit den früher beschriebenen analogen Calcium‐ und Strontiumverbindungen und schmelzen wie diese inkongruent. Die röntgekristallographischen Daten der nunmehr bekannten 6 Verbin…
Summary: The cell walls of six different species of algae were prepared in highly purified form and their amino acid and amino sugar contents determined qualitatively. A limited number of ninhydrin-positive components was found, implying that the walls contain peptide rather than protein. In five of the algal walls, t…
A study was made of the EPR and optical spectra of trivalent erbium in Type II crystals of calcium fluoride. The EPR spectrum disclosed the existence of cubic, tetragonal, and trigonal sites in the approximate ratios 15:20:1. The splitting values agreed with those of Ranon and Low. The optical spectrum consisted predo…