Materials Literature
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Random fibre fields can serve as mathematical models of irregular systems of dislocation lines. The pair-correlation function describes their variability and inner correlations. This paper presents the pair-correlation functions for various fibre field models. The curves and formulae can help to interpret empirical pa…
Full concentration series of tetragonal melilite-like Ca2−xNdxGa2+xSi1−xO7 single crystals with desordered structure are grown using Czochralski technique and their precies X-ray structural analysis is carried out. Intensity, absorption, and luminescence characteristics including orientational ones of Nd2+ ions in Ca2…
It is shown that the commonly used approximation for the no-loss angle-resolved photocurrent from solids in general violates the optical selection rules if the final-state inverse low-energy electron diffraction orbital is taken to be damped. The violations occur in the velocity formula, which is inconsistent with the…
Intrinsic and extrinsic plasmon loss effects are discussed based on the theory proposed by the present author, both for surface and bulk plasmon loss observed in XPS spectra from deep cores. Two types of the incident X-ray polarization are considered here; one is normal to the surface, another is parallel to it. The a…
The complete Raman spectra of ${\mathrm{Na}}_{2}$${\mathrm{CO}}_{3}$ in its monoclinic (\ensuremath{\beta}), incommensurate (\ensuremath{\gamma}), and lock-in (\ensuremath{\delta}) phases, as well as the far-infrared spectra in the \ensuremath{\gamma} and \ensuremath{\delta} phases, have been measured and interpreted…
The structure [C10H13N3O3,Mr=223.23, monoclinic, P21, a=5.182(1) Å, b=14.964(4) Å, c=7.045(1) Å, β=106.76(1)°, V=523.1 Å3, Z=2, Dx=1.42 Mg mm−3, μ=9.0 cm−1, F(000)=236, 23±1 °C, R=(Σ‖‖F0‖−‖Fc‖‖/Σ‖F0‖) =0.047 based on 930 reflections with F20>3.0σ(F20)] of this compound reveals it to optimally satisfy many of th…
The notion of a perfect crystal in d-dimensional physical space may be generalized to the ``deterministic'' quasicrystal generated by a cut by a d-dimensional ``physical'' plane through a periodic array of (D-d)-dimensional hypersurfaces in a D-dimensional space. (The quasicrystal tilings generated by projection from…
Three regimes of pressure and temperature are identified in which silane pyrolysis has distinctly different initial kinetics: in two regimes the initial reactions are heterogeneous and in the third regime it is homogeneous. We report here a preliminary model for the heterogeneous reaction regime where the decompositio…
Diamond has been obtained by ArF excimer laser-induced chemical vapor deposition. The reaction was carried out by use of C2H2 diluted with H2 as a source gas and at the pressure range of 8–75 Torr. The products were characterized by scanning electron microscopy and reflection electron diffraction. Deposits prepared in…
Mutual-diffusion and tracer-diffusion coefficients, $D$ and ${D}^{*}$, are measured in the miscible polymer blend system polystyrene + poly (2,6-dimethyl-1,4-phenyleneoxide) by forward recoil spectrometry. We find $D$ to be much larger than ${D}^{*}$, an increase that is predicted quantitatively by a theory which incl…
Monte Carlo simulations have been performed on a diamond lattice model of semiflexible polymers for a range of flexibilities and a range of chain lengths from 50 to 800 segments. The model includes both repulsive (excluded volume) and attractive segment–segment interactions. It is shown that the polymers group into tw…
Saffman-Taylor experiments are conducted in a circular axisymmetric Hele-Shaw cell. We show that when a small pre-existent isolated bubble comes into contact with the tip of a finger, this finger starts growing faster, its radius of curvature at the extremity is reduced, and it takes a parabolic shape. When its veloci…
Realistic ab initio total-energy calculations are performed to investigate the electronic and geometric structure of crystalline ${\mathrm{As}}_{2}$${\mathrm{Se}}_{3}$. Results include the following: total energies for various distortions, the equilibrium geometric structure, intralayer and interlayer cohesive energie…
I define a hopping Hamiltonian for independent electrons on a two-dimensional, infinite, quasiperiodic Penrose lattice with a particular on-site potential, depending upon a parameter r. I then find the exact ground-state wave function for this Hamiltonian. The wave function is shown numerically to have a power-law dec…
We define a one-parameter family of hopping Hamiltonians with an on-site potential, for independent electrons on a two-dimensional quasiperiodic Penrose lattice. The resulting models include the vibrational modes of the lattice. This problem is then investigated numerically---exploiting the symmetries of the model inc…
The method of molecular-dynamics simulation for an assembly of 6480 soft spheres is used to investigate the layerwise structure of a {111} solid-liquid interface for an fcc crystal. A heterogeneous two-phase structure in each layer is suggested by a 2D Voronoi polygonal analysis but this is not supported by various or…
The structural environment of Bi incorporated in Ge chalcogenide glasses has been found from extended x-ray absorption fine-structure data to consist of threefold coordination. An increase by a factor of 2 in the Debye-Waller factor occurs as the carrier type changes from $p$ to $n$. A mechanism involving the suppress…
A new method for calculating the effect of stacking faults on x-ray and neutron-diffraction patterns is developed. Using a computer-generated, statistically faulted crystal model, we show that it is possible to examine the effect of various types of faults in different lattice types from a simple and unified point of…
A new electro-optical material based on nematic liquid crystal dispersed in a polymer matrix has recently been introduced by Fergason. This technology (termed NCAP, for nematic curvilinear aligned phase) is suitable for making very large area (thousands of square centimeter) light valves and displays. The device consi…
The thermoluminescence (TL) of LiF (TLD-100) has been studied over the temperature range 90 to 300K. A total of nine glow peaks are observed in this temperature interval. The most intense peak is the one at 137K. Besides this, three other peaks at 149, 254 and 275K are well resolved and their growth with exposure coul…