Materials Literature
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The crystal structures of the spinels Co 3 O 4 , NiCo 2 O 4 , Co 3 S 4 , and NiCo 2 S 4 were refined from X-ray and neutron powder data. Their lattice parameters at room temperature and the positional parameters of the oxygen and sulfur atoms were: Co 3 O 4 , 8.0835 ± 6 Å, 0.2640 ± 8; NiCo 2 O 4 , 8.114 ± 14 Å, 0.2583…
The free-ion energy level scheme of Gd3+ (aquo) to ∼52 000 cm−1 has been determined from the absorption spectrum of Gd3+ in dilute acid solution at 25°C. Several new absorption bands near 50 000 cm−1 have been ascribed to transitions from the ground state to components of the 6G multiplet. Energy level assignments wer…
Fifteen of the sixteen known enstatite chondrites were studied microscopically in reflected and transmitted light, and their modal compositions were determined by point-counting techniques. Compositions of clinoenstatite, orthoenstatite, plagioclase, kamacite, taenite, troilite, oldhamite, daubreelite, niningerite, fe…
A total of 23 experimental “free-ion” energy levels of Tb3+ (aquo) have been fit with an rms deviation of 56 cm−1. The resulting parameters are: E1 = 6021.5, E2 = 29.030, E3 = 608.54, ζ4f = 1709.5, α = 20.131, β = − 370.21, and γ = 1255.9. The latter three parameters arise from including the effects of configuration i…
The free-ion energy level scheme of Eu3+ (aquo) to ∼40 000 cm−1 has been determined from the absorption spectrum of Eu3+ in dilute acid solution at 25°. Energy-level assignments were made on the basis of correlations between calculated and observed intensities. A least-squares fit of 26 J levels, including the effects…
We have correlated the experimentally determined band intensities in the solution absorption spectra of the trivalent lanthanides with a theoretical expression derived by Judd. The spectra were measured in a single medium, dilute acid solution, and, in most cases, in the range ≈6000–50 000 cm−1. In general, the correl…
The free-ion energy-level schemes of the Pr3+, Nd3+, Pm3+, Sm3+, Dy3+, Ho3+, Er3+, and Tm3+ aquo ions have been determined from their absorption spectra in dilute acid solution at 25°. Energy-level assignments were made by comparison with crystal spectra, and on the basis of correlations between calculated and observe…
Measurements of the ionization losses of 10.0- to 30-keV ${\mathrm{Ge}}^{72*}$ atoms in germanium show no evidence for a cutoff for particle energies less than 23 keV, as might be expected from adiabatic arguments concerning the effect of an energy gap in germanium. The ionization loss is consistent with Lindhard's co…
A rapid and reversible transition between a highly resistive and conductive state effected by an electric field, which we have observed in various types of disordered semiconducting material, is described in detail. The switching parameters and chemical composition of a typical material are presented, and microscopic…
X-ray diffraction, M\"ossbauer spectroscopic, and magnetic susceptibility measurements have led to a determination of the phase diagram including magnetic phases of the system ${({\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{Fe}}_{x})}_{2}{\mathrm{O}}_{3}$, $0\ensuremath{\le}x\ensuremath{\le}0.63$, the limit of ${\mathrm{F…
The $4{f}^{n}\ensuremath{\rightarrow}4{f}^{n\ensuremath{-}1}5d$ absorption spectra of rare-earth ions, R${\mathrm{E}}^{2+}$ or R${\mathrm{E}}^{3+}$, in crystals can be fitted with energy gaps in the ground multiplets of the $4{f}^{n\ensuremath{-}1}$ core. Unlike the shielded $4{f}^{n}$ configuration, the $4{f}^{n\ensu…
Radiative lifetimes of the six lowest-energy $J=1$ levels of Ar I have been measured using a pulsed electron technique. The wavelengths and measured lifetimes in nanoseconds are 1066.66, 8.60 \ifmmode\pm\else\textpm\fi{} 0.4; 1048.22, 2.15 \ifmmode\pm\else\textpm\fi{} 0.2; 879.95, 10.1 \ifmmode\pm\else\textpm\fi{} 0.4…
Samples in the Bi–Te system containing 59.0, 58.0, 57.0, 55.0, 51.0, and 50.0 at.% Te, in addition to 5 samples within the Bi2Te3 homogeneity range, have been equilibrated near 525 or 450°C and room temperature powder diffraction patterns taken. There are now 4 known phases in the 50–60 at.% Te region. The 59.0 and 58…
Technical Briefs Effect of Transverse Curvature on Skin Friction and Heat Transfer in Laminar Flows Past Slender Circular Cylinders T. Cebeci, T. Cebeci Mechanical Engineering Department, California State College at Long Beach, Long Beach, Calif; Aerodynamics Research Group, McDonnell Douglas Corporation, Douglas Airc…
The asymptotic spherical aberration and distortion coefficients of electron lenses always depend upon the position of the object, or the magnification, in a very simple way, and furthermore the quantities that specify the distortion are closely related to those giving the spherical aberration. These relationships are…
The oxidative photolysis of polyvinylpyrrolidone with light of λ = 2537 Å has been studied over a range of oxygen pressures and polymer concentrations. The results show that chain scission and cross linking take place simultaneously. In the range where cross linking is a negligible component, a mechanism based on chai…
The yield stress data of irradiated Ferrovac iron are shown to be closely approximated by the expression Δ[sgrave]=A[1—exp (—Bφt)]1/2 with a saturation exposure of 2 × 1019 nvt (E > 1·45 MeV). The maximum increment in the yield stress is 25 000 p.s.i. and the volume of the defect calculated from B is 4·4 × 10−19 cm3.…
A method is presented for obtaining the far-field diffraction pattern of a plane aperture when the mutual coherence function of the illumination contains a quadratic phase term. The method is applied to obtain the diffraction pattern of a slit and circular aperture illuminated by an extended quasimonochromatic incoher…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolybdovanadophosphoric acids and their salts. II. Investigation of solution propertiesCalvin J. Hallada, George A. Tsigdinos, and B. S. HudsonCite this: J. Phys. Chem. 1968, 72, 12, 4304–4307Publication Date (Print):November 1, 1968Publication History Published online1 May…
Abstract 9,10‐Bis(hydroxymethyl)triptycene, 9,10‐dihydro‐9,10‐bis(hydroxymethyl)‐9,10‐ethanoanthracene, 9,10‐dihydro‐9,10‐bis(hydroxymethyl)‐9,10‐(2,3‐bicyclo[2.2.1] heptano)‐anthracene, 9,10‐dihydro‐9,10‐bis(hydroxymethyl)‐ N ‐phenyl‐9,10‐ethanoanthracene‐11,12‐dicarboximide, and 9,10‐bis(carbethoxy)triptycene have b…