Spectroscopic Properties of Rare Earths
"Spectroscopic Properties of Rare Earths." Optica Acta: International Journal of Optics, 12(4), p. 413
Materials Literature
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A New Theory of Wood’s Anomalies on Optical Gratings
A new theory of Wood’s anomalies is presented which is based on a guided wave approach rather than the customary multiple scattering procedure. This approach provides both new insight and a method of calculation. It is shown that two distinct types of anomalies may exist: a Rayleigh wavelength type due to the emergenc…
Interspecimen Comparison of the Refractive Index of Fused Silica*,†
The index of refraction of optical quality fused silica (SiO2) was determined for 60 wavelengths from 0.21 to 3.71 μ at 20°C. The dispersion equation n2-1=0.6961663λ2λ2-(0.0684043)2+0.4079426λ2λ2-(0.1162414)2+0.8974794λ2λ2-(9.896161)2.where λ is expressed in microns was found to yield an absolute residual of 10.5×10−6…
Nowackiite, a new copper zinc arsenosulfosalt from Lengenbach (Binnatal, Kanton Wallis)
Es wird die Beschreibung eines neuen Kupfer-Zink-Arsensulfosalzes aus dem Lengenbach gegeben. Das Mineral ist rhomboedrisch (Raumgruppe R3 oder R3¯), von der Zusammensetzung Cu6Zn3As4S12-13 (Mikrosonde, Typ Cameca MS 85) und vermutlich vom Zinkblendetypus.
Theoretical Relationship between Surface Tension and Cohesive Energy Density
The rigid-sphere theory of liquids is shown to yield an expression for the surface tension of a one-component liquid which is essentially identical to an expression previously derived by the author employing a qualitative approach. Such a correlation suggests that the rigid-sphere theory of liquids approach is applica…
Free-Ion and Crystalline Spectra of Pr3+ (Pr IV)
The spectrum of the free tripositive praseodymium ion (Pr IV) has been obtained under high resolution between 1200 Å and the infrared. The analysis has yielded all 49 levels of the four lowest configurations 4f2, 4f5d, 4f6s, 4f6p. A comparison with the crystal levels of Pr3+ in various lattices shows a depression of u…
Electric and Magnetic Properties of the Strontium Ferrates
A series of strontium ferrate compositions ranging from SrFeO2.7 to SrFeO3.0 have been produced by equilibration at oxygen pressures ranging from 0.2 to 855 atm. The stoichiometric composition SrFeO3.0 exhibits a simple cubic perovskite structure (a=3.850 Å). Ceramic disks of this material are conductive (ρ≈10−3 Ω·cm)…
Mössbauer Effect in Ferroelectric BaTiO3
The M\"ossbauer effect for ${\mathrm{Fe}}^{57m}$ in the BaTi${\mathrm{O}}_{3}$ lattice has been studied from 300 to 1200\ifmmode^\circ\else\textdegree\fi{}K with particular emphasis on the region near the Curie temperature. The M\"ossbauer probe seems to serve as a useful tool for the study of ferroelectrics. The elec…
Thermal Expansion of a Uranium Monocarbide—Zirconium Monocarbide Solid Solution
The thermal expansion of a polycrystalline (U0.30, Zr0.70)C0.97 solid solution was determined between 25° and 982°C by means of a high-temperature x-ray diffraction technique. For the range 25° to 1000°C the average linear thermal-expansion coefficient is 7.78×10−6/°C. The 25°C lattice parameter is 4.7822 Å, the calcu…
The infrared spectra of the solid phases in the system BeO-H2O
Chemical and structural information relating to the BeO-H2O system is discussed and correlated. The infrared spectra of α, β, and amorphous Be(OH)2 have been studied in the range 650 to 10,000 cm-1. These show that the constitution of the three hydroxides is similar. The spectra are interpreted to arise from the coupl…
A wide-range (up to 1010 P) rotating cylinder viscometer
1~he ra nge of a hi g h temperature rota Ling cylinde r v iscometer has bee n extended so t hat VISCOSIty m easuremen.ts can be m ad e betwee n 10 0 to 10 10 p oises to within 2-p ercen t a ccuracy. ThiS lllvolves three different tec hniques . After a calibration consta nt has been determined for the apparatus III the…
Exsolution of β‐Ga 2 O 3 Crystalline Solutions in the System MgAl 2 O 3 ‐Ga 2 O 3
The subsolidus phase equilibrium diagram for the pseudobinary join MgAl 2 O 4 ‐Ga 2 O 3 was determined. The shape of the exsolution boundary was obtained by heat‐treating samples pre‐ equilibrated at 1600°C. Crystalline solubility of Ga 2 O 3 in MgAl 2 O 4 decreased from 73 mole % at 1600°C to 55 mole % at 1200°C. The…
THE FEIST SYNTHESIS OF PYRROLE-3-CARBOXYLIC ESTERS
not available
Non-Woven Fabrics. Part VI
Measurements of lateral contraction in the plane of the sheet and of changes in thickness were made on cross-laid and random-laid bonded-nber fabrics subjected to a tensile stress either parallel or at right angles to the machine direction. From these measurements, the corresponding changes in volume were derived. The…
Influence of crystal orientation on friction characteristics of titanium single crystals in vacuum
Friction experiments were conducted in vacuum (10(exp -9) mm Hg) with oriented single- crystal titanium rider specimens sliding on polycrystalline titanium disk specimens. Experiments were conducted at a surface speed of 2.28 centimeters per second and loads from 250 to 1000 grams. Two principal single-crystal orienta…
Diffusion-Limited Climb Rate of a Dislocation: Effect of Climb Motion on Climb Rate
The diffusion-limited climb rate of a straight dislocation immersed in a nonequilibrium concentration of point defects was calculated in the quasisteady-state approximation. It was shown that this approximation should apply in many cases of interest. Full account was taken of the effect of the dislocation climb motion…
EFFECT OF WATER VAPOR ON THE FORMATION OF MODIFICATIONS
The two recognized forms of calcium sulfate hemihydrate can be identified by the position of a relatively small exothermic peak in their differential thermograms. Hemihydrates prepared at various water vapor pressures up to 760 mm Hg were found to produce this exothermic peak in a position which is characteristic for…
Young's modulus of pyrolytic carbon in relation to preferred orientation
Expressions are derived which express Young's modulus of an anisotropic aggregate of hexagonal crystallites in terms of the single-crystal elastic constants and functions of the preferred orientation, assuming either a constant tensile strain or a constant tensile stress throughout the aggregate. Measurements of Young…
Crystallinity of ethylene–vinyl acetate copolymers
Abstract Determination of crystallinity of ethylene–vinyl acetate copolymers according to the usual x‐ray diffraction method employed for polyethylene is very much hampered by the fact that these copolymers are usually largely amorphous and the Bragg reflections in their diffraction diagrams which are therefore broad…
Structure and Annealing Behavior of Metal Films Deposited on Substrates near 80 °K. II. Gold Films on Glass
An in situ x-ray investigation of gold films has been carried out. Films were deposited on glass near 80 °K in high vacuum. Measurements were made on the as-deposited films as well as after annealing at temperatures up to 370 °C. In the as-deposited films the following results were obtained: (1) The lattice parameter…