Materials Literature
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In the temperature range from 848 to 1169 K chemical diffusion coefficients of Zn in α-Fe are given for Zn concentrations between 0 and 12 at%. Above 1068 K the tracer diffusion coefficient (nzn → 0) can be described by an Arrhenius law with D0 = 60 cm2 s−1 and Q = 262.6 kJ mole−1. For lower temperatures the diffusion…
The phase transition of NaNO2, is investigated by using X-ray powder diffractometry. The temperature dependence of the lattice constants, peak intensities, and the order parameter of the ferroelectric phase, in the range of 27 to 200 °C, show the same results as obtained by using single-crystal diffractometry. These e…
The properties of regions swept by a moving dislocation in silicon crystals are experimentally studied. The peculiarities of forming traces of various types behind dislocations observed by electron microscopy and chemical etching are investigated. These traces are found to arise as result of point defect redistributio…
The systematics of the onset of deformation in the $N=88\ensuremath{-}90$ region is reexamined in light of the recently discovered shell closure at $Z=64$. It is shown that the microscopic explanation of the origin of deformation already proposed for the $A\ensuremath{\sim}100$ region is equally applicable here and le…
Polyacetylene (CH)z is a simple conjugated polymeric system, the electrical behaviour of which is considerably modified by doping processes: from an insulating behaviour it successively becomes semi-conducting and even metallic. In this work first the dopant profiles through the sample is measured and the macroscopic…
An electron trap which strongly affects the photoconductivity of colored $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ has been investigated from 10 to 300 K. The trap, which also causes the 260-K thermoluminescence peak and makes possible the interconversion of $F$ and ${F}^{+}$ centers by opti…
Photodissociation of XeF2 with synchrotron light pulses (0.3 ns duration) has been used as the source of the XeF(B, C, and D) excited states. The time-resolved profiles of the intensity of the resulting fluorescence have been recorded and partially analyzed. Most of the measurements were made in the strong XeF2 absorp…
The solid–vapor equilibrium line and the liquid–vapor equilibrium line near the melting region for classical two-dimensional systems of particles interacting by Lennard-Jones (12,6) pair potentials are determined from Monte Carlo simulations with 224 particles. Structural and thermodynamic properties are evaluated for…
A general formula is derived for the electron occupation numbers appropriate for multicharge centers in semiconductors, including excited states. The results are used to rederive and generalize several formulas of interest in the literature, in order to show exactly how the degeneracies of individual states enter in.…
A theoretical study of the electronic structure of amorphous $\mathrm{Si}{\mathrm{O}}_{x}$ is performed. The calculation is done using a realistic tight-binding Hamiltonian for a cluster-Bethe-lattice model. Results of the calculations are in good agreement with optical-absorption measurements for the entire range of…
The quantum statistical mechanics of a polarizable fluid model is considered using a path-integral approach. The quantum mechanical partition function associated with the internal degrees of freedom of each molecule is approximated by a classical partition function of a polymer ring, while the center-of-mass motion of…
Synchrotron radiation at the Synchrotron Ultraviolet Radiation Facility at the National Bureau of Standards has been employed to study the adsorption of oxygen on a Ti(001) surface using photon-stimulated desorption (PSD), electron-stimulated desorption (ESD), and ultraviolet photoemission spectroscopy (UPS). The domi…
The ground-state properties of diamond are investigated using an ab initio density-functional pseudopotential scheme. The calculated equilibrium lattice constant, cohesive energy, and bulk modulus are in excellent agreement with experiment. Unlike Si, a double hump is found in the valence-electron charge density along…
Excited $s$ states are added to the minimal-basis tight-binding theory of covalent solids using Louie's perturbation approach. This brings the conduction bands into better accord with experiment without appreciably complicating the calculation of properties in the bond-orbital approximation. Universal interatomic matr…
We report on a high-resolution photoluminescence and absorption study with the application of external stress and magnetic fields on the 0.97-eV ($G$) line. We determine the symmetry of the related center to be monoclinic $I$. It is shown that satellite lines $E$, ${E}^{\ensuremath{'}}$, and ${E}^{*}$, which are obser…
Elastic and hydrodynamic properties of biaxial nematics of D2 symmetry are theoretically studied. The treatment follows closely the classical formalism used for solids which is extended by inclusion of director fields. The resulting theory is a generalization of the well-established theory of uniaxial nematics. The el…
We present measurements of light emission from Al-${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$-Ag tunnel junctions on holographically produced, sinusoidal profile gratings. Sharp angle tunable emission peaks result from coupling out of the Ag-vacuum fast surface-plasmon polariton by the grating structure. The dependences of…
A method is proposed for calculating the photoionisation cross sections of many-electron atoms near the ionisation threshold of an inner shell. The method takes into account the variation of the field in which a photoelectron moves due to creation of a deep vacancy and its decay. For example the cross section of the 1…
The dielectric strength of hexafluoropropylene has been investigated under breakdown and prebreakdown conditions in the pressure range from 0.07 to 2 bar. Breakdown voltages measured in a uniform field gap have been found to be in good agreement with intrinsic dielectric strength evaluated from measurements of net ion…
The Ni L 2,3 M 4,5 M 4,5 Auger spectra, the conduction band X-ray photoemission spectra and the Ni 2p 3/2 X-ray photoemission spectra have been measured for Ni, Ni 50 Zn 50 , Ni 20 Zn 80 and Ni 50 Al 50 . The shape of the L 3 M 4,5 M 4,5 Auger spectrum changes as the band structure of the alloy changes in a way which…