Materials Literature
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Whewellite and weddellite, calcium salts of oxalic acid, have been found in the litter layer of several different soils, indicating that oxalate is a major metabolic product of fungi in natural environments. The presence of oxalate in soil solution speeds weathering of soil minerals and increases the availability of n…
The programming of the R-matrix method recently used to calculate total and partial atomic photoionisation cross sections has been extended to enable photoelectron angular-distribution beta parameters to be studied for a general atomic system. The program has been used to calculate the beta -parameters for photoelectr…
Earlier ideas are combined to produce a systematic approach both to forming the bulk equations of motion of a dilute suspension and to calculating the overall hydrodynamic interactions between the suspended particles. Equations governing averaged field quantities are derived by taking ensemble averages of the conserva…
The change in the grain-boundary structure during superplastic deformation of a magnesium alloy (Mg + 1.5% Mn + 0.3% Ce) is investigated by diffraction electron microscopy. The presence of linear defects, extrinsic grain-boundary dislocations (EGBD), is established, whose density depends weakly upon the degree of exte…
A low-energy argon ion-beam sputtering system was developed and applied to serial sectioning in a radiotracer study of “low”-temperature self-diffusion of copper. Very thin uniform sections with thicknesses between several nm and a few hundred nm were removed from copper single crystals of extremely low dislocation de…
The molecules MnO, MnO2, MnO3, and MnO4 have been prepared by the vaporization and reaction of manganese atoms with O2, N2O, or O3 and isolated in various inert-gas matrices at 4 °K. ESR has been used to determine magnetic parameters which are interpreted in terms of molecular geometry and electronic structure. MnO is…
Using the time-differential Mössbauer coincidence technique we have measured emission spectra of [57Co(phen)3] (ClO4)2⋅2H2O (phen=1, 10-phenanthroline) in the temperature range 10–80 K versus K4[Fe(CN)6]⋅3H2O as absorber. The lifetimes of the unstable 57Fe(II) high-spin states (5T2), which are formed as a consequence…
The optical constants relative to each crystallographic axis of Ga monocrystals in the range 0.3-5 eV have been determined from reflectance measurements at normal incidence with the light being polarized parallel to each axis. We report on thermoreflectance spectra and give the corresponding changes in the dielectric…
Thermal quenching of Li-doped MgO crystals from temperatures in excess of 1300 K results in the formation of ${[\mathrm{Li}]}^{0}$ defects, which are substitutional lithium ions each with a bound hole at a neighboring oxygen site. Unlike ${[\mathrm{Li}]}^{0}$ defects generated at low temperatures by a low dose of ioni…
Decay patterns of trapped electrons in aqueous glasses have been analyzed over the time span of more than eight decades in terms of a time-dependent "rate constant" of the form ${t}^{\ensuremath{\alpha}\ensuremath{-}1}$, $0<\ensuremath{\alpha}<1$, which can be derived from the long-tail hopping-time distribution…
Using a Si surface model involving interference between two rippled-surface double layers, a kinematic analysis of low-energy-electron-diffraction (LEED) intensities of all fractional-order spots has been completed and compared with recent experimental LEED 7 \ifmmode\times\else\texttimes\fi{} 7 intensity data. Since…
A" the baris oJ cOlltilluum model , theoretical equatioll which describes a stress-straill cllrve oJ dual phase steel is built up Jrom the stress-straill curves oJ each composite phase.The comparisoll oJ theorelical result, with experimenla l onts is made on the cOlltilll/ously alll/ealed dual phase steel which is com…
Ultraviolet photoemission spectroscopy (UPS) has been used to study the valence-band electronic structure of $2H\ensuremath{-}\mathrm{M}\mathrm{o}{\mathrm{S}}_{2}$. The samples were cleaved or heated in ultrahigh vacuum of \ensuremath{\sim} 1 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}10}$ Torr to achieve…
Photoemission spectra of the valence band of single-crystal graphite were measured using synchrotron radiation in the energy range 33-200 eV. For $\ensuremath{\hbar}\ensuremath{\omega}=122$ eV, good agreement was found with the calculated density of states since the matrix elements for the $p$-like and $s$-like states…
An attempt is made to describe the kinetics of diffusionless first order phase transformations in terms of the time-dependent Landau–Ginzburg equation. A steady-state solution to the equation is presented such that an interface may propagate with a shape-preserving profile under constant supercooling. The laws of grow…
Microwave and far-infrared absorption have been studied in several chalcogenide and oxide glasses (${\mathrm{As}}_{2}$${\mathrm{Se}}_{3}$, ${\mathrm{Tl}}_{2}$Se${\mathrm{As}}_{2}$${\mathrm{Te}}_{3}$, 3Si${\mathrm{O}}_{2}$ \ifmmode\cdot\else\textperiodcentered\fi{} ${\mathrm{Na}}_{2}$O) at frequencies between 0.1 and 1…
The electrochromic optical absorption of mixed-oxide WO3/MoO3 amorphous films occurs at higher energy than either pure oxide alone. The systematics of the energy shifts as a function of MoO3 concentration and coloration density is determined. The data is explained by the intervalency charge-transfer model if we assume…
LEED calculations are presented which indicate that the emergence of a non-specular beam is accompanied with a surface resonance fine structure in the intensity of the specular beam. It is shown that the fringes of the fine structure are arranged in a Rydberg series having the constant 1 / 16 Rydbergs and terminating…
Using precise lattice-parameter measurements, "cubic" ${\mathrm{Na}}_{x}\mathrm{W}{\mathrm{O}}_{3}(0.62<~x<~0.94)$ has been found to transform from the ideal perovskite structure to three other related forms. The transition sequence is described in terms of a single vectorlike order parameter involving static in…
A large differnce in widths and intensities between Stokes and anti-Stokes spin-flip Raman scattering lines of donor electrons in $n$-CdS has been observed. This asymmetry arises from the linear $k$ term, $\ensuremath{\lambda}(\stackrel{\ensuremath{\rightarrow}}{\mathrm{k}}\ifmmode\times\else\texttimes\fi{}\stackrel{\…