Materials Literature
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Etching and homoepitaxial growth were performed on 0.1°, 3.5°, and 11.0° off (001) diamond substrates using microwave plasma-assisted chemical vapor deposition. Etched surfaces showed a sequential morphological change from etch pits to stepped surface to flat surface with increasing misorientation angle. In homoepitax…
Pulsed-laser deposition of smooth high-Tc superconducting films almost free from droplets and precipitates with the use of velocity filtration of plasma particles is reported. We have removed droplets from laser-induced plasma by using a shutter technique; a reduction of the droplet density by a factor of 105 has been…
Epitaxial Ba0.5Sr0.5TiO3 (BST) thin films were deposited on LaAlO3 substrates with the conductive metallic oxide SrRuO3 (SRO) as a bottom electrode by pulsed laser deposition. The BST and SRO films were (𝒽00) and (00ℓ) oriented normal to the substrate surface, respectively. The epitaxial nature of both BST and SRO lay…
A spiral state is proposed to be the stable magnetic structure of perovskite $(\mathrm{L}\mathrm{a}\ensuremath{-}X){\mathrm{MnO}}_{3}$ ( $X$: Ba, Ca, or Sr) with a low concentration of $X$ ions, contrary to the canted state predicted before. We use a mean field approximation applied to a model which treats ${t}_{2g}$…
We present a new method to determine the lateral depletion length (LDL) at the boundary of a two-dimensional electron system (2DES). This approach exploits the fact that in high magnetic fields certain plasma excitations of the confined 2DES (edge-magnetoplasmons, EMPs) are sensitive to details of the density profile…
The surfaces of rubbed polyimide films for aligning liquid crystal have been studied by atomic force microscopy. The unrubbed films consisted of randomly distributed polyimide clusters of different sizes. On the rubbed surface, however, the clusters are aligned in long chains along the rubbing direction. The cluster c…
The normal state of the layered organic superconductors $\ensuremath{\kappa}\ensuremath{-}(\mathrm{B}\mathrm{E}\mathrm{D}\mathrm{T}\ensuremath{-}\mathrm{T}\mathrm{TF}{)}_{2}X$ ( $X\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\mathrm{Cu}(\mathrm{NCS}{)}_{2}$ and Cu[N(CN${)}_{2}$]Br) has been studied by ${}^{13}$C…
A detailed investigation of the dependence of the photoluminescence from porous silicon carbide on preparation conditions and starting material is presented. Porous silicon carbide prepared from different polytypes shows almost identical emission spectra, demonstrating a clear impedance of the band-gap energy of a par…
Consequences of the modified dielectric properties of semiconductor crystallites are explored. The notion and usefulness of an effective dielectric constant are analyzed using a self-consistent linear screening calculation. The binding energy of hydrogenic impurities is defined and calculated, and it is shown why thes…
The structural elements in a rock are characterized by their density in Preisach-Mayergoyz space (PM space). This density is found for a Berea sandstone from stress-strain data and used to study the response of the sandstone to elaborate pressure protocols. Hysteresis with discrete memory, in agreement with experiment…
Dynamic and static light scattering is applied to concentrated suspensions of a new species of charged colloidal suspensions with a low refractive index. The polymer colloids which were obtained by polymerizing perfluorobutylacrylate could be index matched in a water/glycerol mixture. At volume fractions Φ greater tha…
Fourier transform infrared measurements on the spectra of the products of the vaporization of silicon/carbon mixtures trapped in solid argon in concert with ab initio calculations using second order many body perturbation theory have resulted in the identification for the first time of two vibrational fundamentals, ν3…
The molecular-based magnetic materials Cs(2)Mn(||)[V(||)(CN)(6)] (1) and (Et(4)N)(0.5)Mn(l.25)- [V(CN)(5)].2H(2)O (2) (where Et is ethyl) were prepared by the addition of manganese(II) triflate to aqueous solutions of the hexacyanovanadate(II) ion at 0 degrees C. Whereas 1 crystallizes in a face-centered cubic lattice…
A novel design for a zero-order achromatic diffractive optical element is presented. Applications of the optical element are discussed. Tolerances on the material properties and fabrication considerations are presented. The predicted performance characteristics, including optical efficiency and effective bandwidth, ar…
In the present communication we describe the investigation of local structure using a new visualization technique. The approach is based on two-dimensional pair correlation functions derived from a molecular dynamics computer simulation. We have used this method to analyse a trajectory produced in a simulation of a ne…
We report grand canonical Monte Carlo simulations at 298 K for a model of water in graphitic carbon pores of slit shape, for a range of pore widths from 5 to 27 Å. Large systems (typically 500–1000 water molecules and 2016 carbon atoms) and long runs (30–50 million configurations) were used, and the structure of the c…
Abstract Poly(ethylene terephthalate) (PET) taken from postconsumer soft‐drink bottles was subjected to solid‐state polycondensation after cutting into small pieces or after dissolution in trifluoracetic acid, trifluoracetic acid/dichloromethane mixture (50/50%, v/v), or nitrobenzene, and coagulation in methanol. The…
The 248 nm UV photosensitivity of H2 loaded optical fibers is shown to be significantly enhanced by increasing the temperature during the UV exposure. Heating to 250–400 °C resulted in dramatic UV reaction rate increases in GeO2 doped fibers. Increasing the core temperature during 248 nm irradiation caused P2O5 doped…
Melts of many silicates are known to have an anomalous transport property in that the diffusivity of oxygen atoms drastically increases with pressure. Here we propose a mechanism for the anomalous diffusion process in liquid silica and silicates on the basis of molecular dynamics (MD) results for pressure-induced stru…
Electron beam deposition (EBD) is a maskless technique suitable for the fabrication of nanometer scale structures. Metals can be deposited from an organometallic gas, but simultaneous carbon deposition typically yields grossly impure (∼25% metal) deposits. We have found that the metal content of the deposited solid is…