Materials Literature
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Abstract The mechanism of boron uptake by clays, especially illitic clays, and the factors which control such uptake have long been debated issues. In an attempt to answer some of the questions of the controversy, three illites were treated in solutions containing boron. In the study, boron concentration, salinity, te…
THE VIEW THAT THE PLANT CELL GROWS BY THE YIELDING OF THE CELL WALL TO TURGOR PRESSURE CAN BE EXPRESSED IN THE EQUATION: rate = cell extensibility x turgor. All growth rate responses can in principle be resolved into changes in the 2 latter variables. Extensibility will relate primarily to the yielding properties of t…
A new electro-optic effect is presented, based on guest-host interactions in nematic liquid crystals. The ability of a nematic liquid crystal to cooperatively align in an electric field is used to orient ``guest'' dichroic dye molecules (molecules whose absorption spectrum is a function of the molecular orientation wi…
A new allotropic form of carbon occurs in shock-fused graphite gneisses in the Ries Crater, Bavaria. The assemblage in which it occurs consists of hexagonal graphite, rutile, pseudobrookite, magnetite, nickeliferous pyrrhotite, and baddeleyite. Electron-probe analyses indicate that the new phase is pure carbon. It is…
A fourteen-faced space-filling polyhedron which closely approximates the actual distribution of four-, five- and six-sided polygons found in packings of soap bubbles and biological cells is proposed as an alternative to the Kelvin tetrakaidecahedron as the ideal polyhedron for these packings. This polyhedron may also…
The photoluminescence spectrum of gel-grown P${\mathrm{bI}}_{2}$ single crystals reveals features at 2.41, 2.31, 2.16, 2.13, 2.10, 1.99, 1.97, 1.94, and 1.85 eV, and the photoconductive response spectrum at 3.06, 2.41, 2.16, and 1.99 eV. An analysis of temperature quenching of the photocurrent indicates sensitizing ce…
The infrared spectra of matrix isolated CsOH and CsOD have been observed. Both the CsO stretching and the bending mode have been assigned for each species. The Cs–O stretching mode ν2 is observed at 335.6 and 330.5 cm−1 for CsOH and CsOD, respectively; the bending mode ν2 is observed at 306 and 226 cm−1, respectively.…
Phosphorescence spectra of pure crystalline naphthalene at room temperature and at 77°K are presented. In addition to the 0, 0 transition at 4715 Å, the spectra show several intense vibronic bands that correlate well with the most intense vibronic transitions observed in isotopic mixed-crystal phosphorescence spectra…
The thermoelectric power of dilute alloys of aluminum with Ag, Zn, Mg, and Au has been measured versus pure aluminum between 4.2 and 460\ifmmode^\circ\else\textdegree\fi{}K. The solute concentrations were in general 0.1 at.% or smaller. The absolute thermopower of high-purity Al has been measured between 4.2 and 300\i…
Evidence for molecular association of liquid TiCl4 is presented. The chlorine isotope structure in the totally symmetric fundamental cannot have originated from a simple tetrahedral molecule belonging to the Td point group. High-resolution measurements, which indicate an associated complex of lower symmetry, possibly…
The two principal components of the mean square atomic displacement differences due to thermal vibrations in zinc have been measured from single-crystal x-ray diffraction intensities over a thermal range from 4.85 to 600\ifmmode^\circ\else\textdegree\fi{}K. The absolute value of the components of the mean square atomi…
The optical functions ${\ensuremath{\epsilon}}_{1}$, ${\ensuremath{\epsilon}}_{2}$, $\ensuremath{\alpha}$, and $\ensuremath{-}\mathrm{Im}(\frac{1}{\ensuremath{\epsilon}})$ have been deduced from reflectance data on electron-gun-evaporated Pt samples. They were obtained by two different methods: (1) the Kramers-Kroning…
The effect of strain, in particular the effect of varying the rate of its application, both in the elastic and the plastic region, on the anodic dissolution kinetics of several metals has been studied. It has been found in the case of iron in acid solution that the over-all effect of elastic strain is small (i.e., the…
Structure has been observed in the photoconductivity spectrum of semiconducting diamond at energies below the ionization threshold. Photoconductivity maxima in this spectral region have been found to coincide exactly with maxima in the absorption spectrum associated with transitions to excited states of the aluminum a…
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The use of a spin-\textonehalf{} formalism to analyze paramagnetic and paraelectric resonance experiments of "non-Kramers" doublets leads to a break with the accepted meaning of effective-spin Hamiltonians. The operators appearing in the Hamiltonian do not have the transformation properties of spin angular momentum in…
The procedures developed in two previous papers by the authors for calculating the parameters $D$ and $E$ in the spin Hamiltonian ${\mathcal{H}}_{s}=D[3{{S}_{z}}^{2}\ensuremath{-}S(S+1)]+E({{S}_{x}}^{2}\ensuremath{-}{{S}_{y}}^{2})$ for iron-group $3{d}^{5}(^{6}S)$ ions are applied to a distorted cubic system, namely,…
Crystal-field splittings in a high-symmetry phase may leave an orbitally degenerate ground state. Three types of degeneracies are considered: (1) a twofold degeneracy that carries no orbital angular momentum, (2) a twofold degeneracy that carries an orbital angular momentum, and (3) a threefold degeneracy that carries…
Spontaneous-emission probabilities for electric- and magnetic-dipole transitions from excited electronic states of ${\mathrm{Pr}}^{3+}$, ${\mathrm{Nd}}^{3+}$, ${\mathrm{Eu}}^{3+}$, ${\mathrm{Er}}^{3+}$, and ${\mathrm{Tm}}^{3+}$ impurities in ${\mathrm{Y}}_{2}$${\mathrm{O}}_{3}$ are calculated using eigenstates in inte…
We report the first clear evidence that rf magnetic fields generate acoustical side-bands in the M\"ossbauer spectra of metallic ${\mathrm{Fe}}^{57}$. We advance an explanation of this magnetoacoustic effect in terms of magnetostriction, and suggest that this effect provides a consistent explanation of the results of…