Materials Literature
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The configuration ions and have been incorporated in strontium fluorovanadate (SVAP) crystals grown using the Czochralski technique. Such crystals provide fourfold-coordinated sites for occupancy by the and ions, which are located near the centres of their respective tetrahedrally bonded molecular ions and . The optic…
We have demonstrated the 1.5 μm electroluminescence from implanted Er ions inside the SiO2 insulator of a silicon metal-oxide-semiconductor structure under forward bias. The Er ions are excited by the direct impact from electrons tunneling through the oxide at electric fields larger than 6 MV/cm. Under these condition…
A thin Er2O3 layer grown on a Si surface by vapor doping of Er exhibits intense photoluminescence in the green and red regions excited by laser beams in the 800 nm and 450–490 nm ranges. These intense light emissions take place via resonant two or one step photoexcitations of the 4f levels in Er3+ ions. Our sample fab…
An algorithm for the design of diffractive optical phase elements (kinoforms) that give rise to fan-out (i.e., spot) patterns was developed and tested. The algorithm is based on the Helmholtz-Kirchhoff rigorous scalar diffraction integral for the evaluation of the electric field behind the kinoform. The optimization o…
CdS films were grown by chemical bath deposition. The as-grown films had the cubic CdS crystalline structure. As-grown films were thermally annealed in a controlled atmosphere. The annealing temperature was varied from 200 to . The annealing process produces a gradual structural transition from cubic for the as-grown…
We fabricated a homeotropically aligned nematic liquid crystal display with positive dielectric anisotropy, whose on and off states are controlled by in-plane field. The rubbing-free device, dark in voltage-off state, reveals bright uniformity in all directions due to the dual domainlike director configuration in the…
The mechanism for cross slip of a screw dislocation in Cu is determined by atomistic simulations that only presume the initial and final states of the process. The dissociated dislocation constricts in the primary plane and redissociates into the cross-slip plane while still partly in the primary plane. The transition…
The pressure-induced variations of the anisotropic charge-transport and magnetic properties have been investigated for a bilayered manganite crystal, ${\mathrm{La}}_{2\ensuremath{-}2x}{\mathrm{Sr}}_{1+2x}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ ( $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.3$). The magnitude of t…
It is demonstrated theoretically that particle irradiation may lead to a destabilization of graphitic structures with respect to low-pressure growth of diamond. This is due to the large difference in the cross sections for irradiation-induced displacements of carbon atoms in diamond and graphite. A nonequilibrium phas…
Until now, it has been observed that a collective handling of uniform spheres could only lead to a random close packing of 0.64 maximum volume fraction. In this Letter, we show that denser crystalline arrangements can be obtained when beads are poured at low flow rates into a horizontally shaken container. A parallel…
The photoluminescence (PL) and electroluminescence (EL) properties of Ge-implanted SiO2 layers thermally grown on a Si substrate were investigated and compared to those of Si-implanted SiO2 films. The PL spectra from Ge-implanted SiO2 were recorded as a function of annealing temperature. It was found that the blue-vio…
Understanding the thermal conductivity and heat transfer processes in superlattice structures is critical for the development of thermoelectric materials and optoelectronic devices based on quantum structures. This letter reports modeling of the heat transfer and thermal conductivity of superlattice structures based o…
Silicon dioxide films grown by industrial thermal furnace, rapid thermal, and low-pressure thermal methods were measured by x-ray photoelectron spectroscopy, transmission electron microscopy (TEM), spectroscopic ellipsometry, and capacitance–voltage analysis. Based on TEM measurements, the photoelectron effective atte…
The development of the ordered channel array in the anodic porous alumina was initiated by the textured pattern of the surface made by the molding process, and growth of an almost defect-free channel array can be achieved throughout the textured area. The long-range-ordered channel array with dimensions on the order o…
Dynamics of coarsening of a statistically homogeneous fractal cluster, created by a morphological instability of diffusion-controlled growth, is investigated theoretically. An exact mathematical setting of the problem is presented that obeys a global conservation law. A statistical mean field theory is developed that…
We simulate dense diblock copolymer melts using the lattice bond-fluctuation method. Letting the lengths NA and NB of the A- and B-subchains vary (with NA+NB=N) we study the dependence of the static and dynamic properties on f=NA/N. Changes in the A-B interaction parameter allow to mimic large temperature variations.…
Monte Carlo simulations have been performed for a discotic liquid crystal composed of Gay–Berne particles. On the basis of these simulations for the nematic phase, a subset of the spherical harmonic expansion coefficients of the direct pair correlation function (DPCF) were determined from the pair distribution functio…
We carry out extensive molecular dynamics simulations in order to evaluate the thermodynamic equation of state of the extended simple point charge model of water (customarily described by the acronym SPC/E) over a wide range of temperature and density, with emphasis on the supercooled region. We thereby determine the…
The network structure of natural rubber (NR) achieved during vulcanization was analyzed using the model of rubber elasticity based on the tube concept, applied to the treatment of the stress-strain measurements. This theory allows the separation of constraint and crosslink contributions. Also, network parameters can b…
Epoxy-based divinyl ester resins (DVER) were obtained by reacting diglycidyl ether of bisphenol A (DGEBA) with methacrylic acid (MA) and characterized by FTIR and 1H-NMR spectroscopies and gel permeation chromatography (GPC). The densities and viscosities of the DVER in styrene (S) solutions were measured at different…