Materials Literature
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Calculations of the atomic and electronic structure of Ca-Mg glasses and of the crystalline intermetallic compound ${\mathrm{CaMg}}_{2}$ are presented. For the glasses, the calculations are based on realistic models of the atomic structure constructed by a molecular-dynamics computer simulation linked to a steepest-de…
The structure of $\ensuremath{\mu}$-Mn${\mathrm{Al}}_{4}$ has been determined by single-crystal x-ray diffraction. The space group is $\frac{{P6}_{3}}{\mathrm{mmc}}$, $a=19.98(1)$, $c=24.673(4)$ \AA{}A, with 563 atoms per cell (average), and the formula is Mn${\mathrm{Al}}_{4.12}$. Parts of the structure resemble that…
We have examined the electronic and structural properties of elemental copper using pseudopotentials and a local-orbital basis consisting of Gaussians. We find we can use a much weaker ionic pseudopotential to describe accurately the measured band structure, cohesive energy, lattice constant, and compressibility of co…
A new approach is described for the prediction of the optical properties of amorphous tetrahedrally bonded materials over the entire experimental energy range, in which a model of the imaginary part of the dielectric constant is assigned and the real part is obtained by the Kramers–Kronig transform. Tight-binding theo…
We have successfully collected size-selected Au clusters from a liquid-metal ion source onto amorphous carbon substrates. The systematics of the photoemission spectra show that there was no significant fragmentation or coalescence of clusters with seven or more atoms. We estimate the transition from metallic to local…
Molecular dynamics simulation has been performed with an assembly of n-alkane-like chains subject to potentials restricting bond lengths, bond angles, and trans–gauche dihedral angles and interacting with neighboring chains according to a truncated Lennard-Jones potential. The system, on stepwise cooling under constan…
The temperature-dependent microscopic structure of plasma-deposited a-C:H and magnetron-sputtered a-C films, in situ sputter cleaned by argon bombardment, has been investigated by near-edge (NEXAFS) and extended (EXAFS) x-ray-absorption fine-structure studies. We find that the microscopic structure of the two films be…
Reversible thermochromism in thin solid films of poly(3-hexylthiophene), or P3HT, has been studied using ultraviolet and x-ray photoelectron spectroscopies (UPS and XPS, respectively). The UPS and XPS spectra, as well as previously published optical absorption spectra, are analyzed using the results of valence effecti…
We have performed thermal-conductance measurements on polished single crystals of pure silicon in the low-temperature boundary-scattering regime. Our data show that the thermal conductance depends not only on the sample size, but also on the size and spacing of the thermometers used to measure the temperature gradient…
This paper examines the usefulness of cylinder-impact test data to determine constants for various computational constitutive models. The Johnson–Cook and Zerilli–Armstrong constitutive models are evaluated by comparing model predictions to tension, torsion, and cylinder-impact test data. Then the cylinder-impact test…
Cross sections for the production of O - by electron attachment to NO are reported. It is found that the maximum value of the cross section is about 52% higher than the only other previous measurement of Rapp and Briglia (1965). Cross sections for the process of polar dissociation (e+NO to N + +O - ) have also been me…
The influence of the plasticiser DOP on electric conduction and dielectric relaxation in polyvinyl chloride has been investigated. The results were explained in terms of the compensation law between the pre-exponential factor of an Arrhenius equation and its activation energy. This compensation law has been observed n…
New high-temperature superconductors based on oxides of thallium and copper, but not containing barium, have been prepared. A transition temperature (T(c)) of about 85 K is found for (Tl(0.5)Pb(0.5)) Sr(2)CaCu(2)O(7) whereas (Tl(0.5)Pb(0.5))Sr(2)Ca(2)Cu(3)O(9) has a T(c) of about 120 K. Both materials possess tetragon…
We report a linear correlation between the total intensities of the L2,3 white lines in electron energy loss spectra and the number of unoccupied 3d states in 3d transition metals. We show that this correlation can be used to obtain quantitative information about electronic changes during alloying and during solid-sta…
Abstract This paper is concerned with the way that nitrogen impurity in type Ia diamond is distributed between the defects responsible for the principal impurity-dependent infrared absorption maxima in the 7-11 µm wavelength range. The defects involved are the platelets on diamond {100} planes, which produce the B´ ab…
Presents thorough coverage of the transport properties of ions in gases. Starts from first principles, making this book useful to those new to the field as well as to experts. Describes the motions of ions in gases in electric fields, methods for measuring mobilities and diffusion coefficients, and pitfalls in measuri…
Superconducting BiCaSrCu2Ox glass rods and coils were successfully prepared by pumping up the melt at 1150 °C into SiO2 or Pyrex glass tubes. After the outer glass tubes were removed, the resultant glass rods up to 30 cm long were crystallized under a temperature gradient of 30 °C/mm without deforming and cracking. Th…
A transmission electron microscope study of the structures of grain boundaries in zinc has been performed. Dislocation structures are observed in many high angle boundaries, and in most cases, the boundaries that exhibit such structure are close in misorientation to a coincidence site lattice (CSL) forming misorientat…
Abstract Electron–hole recombination luminescence is investigated in CsCdBr 3 crystals. This luminescence consists mainly of a single band at 1.9 eV, assigned to a transition 3 Σ → 1 Σ . The comparison between this emission and emission observed under the 4 eV excitation confirms that the latter is due to Br centers.
Disclinations in thin crystals of MgCd alloy are demonstrated by high resolution electron microscopy. The disclinations appear along the intersection lines of twin boundaries which occur due to spontaneous lattice deformations at the phase transition temperature. A star-disclination which is not an intersection line c…