Materials Literature
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A theoretical expression for the brightness of powder phosphor is derived in order to investigate the effects of phosphor’s properties on low-energy cathodoluminescence. It contains the particle size, surface recombination rate, lifetime of holes, carrier diffusion coefficients, and anode voltage. As such, it can be a…
A carbon-nitride compound with defect zincblende structure (P4̄3m) has been discovered in samples prepared by a chemical precursor route. Crystallographical (high-resolution electron microscopy and electron nanodiffraction) and electron energy loss measurements has been performed to identify the material as cubic zinc…
The effects of encapsulated metal salts on poly(DL-lactide-co-glycolide) (PLGA) water uptake and degradation properties were investigated in this work. Salts of varying aqueous solubility characteristics were incorporated into PLGA films either as particles or by codissolution in polymer solutions. Polymer films were…
Epitaxial ${\mathrm{VO}}_{2}$ layers have been grown on the ${\mathrm{TiO}}_{2}$(110) rutile surface up to thicknesses of 5 ML. These ultrathin films have been characterized by means of x-ray photoelectron spectroscopy (XPS), x-ray photoelectron diffraction (XPD), low-energy electron diffraction (LEED), and ultraviole…
We report Hall coefficient (${\mathrm{R}}_{\mathrm{H}}$ ) and magnetoresistance (\ensuremath{\Delta}\ensuremath{\rho}/\ensuremath{\rho}) measurements on thin films of aligned carbon nanotubes. ${\mathrm{R}}_{\mathrm{H}}$ is positive in the whole temperature range (1.7--300 K) showing the predominance of hole transport…
On measuring the dependence of the magnetic susceptibility of (CH 3 ) 2 CHNH 3 CuCl 3 on the temperature, we find that this compound forms ferromagnetic and antiferromagnetic alternating linear chains with S =1/2. The magnetic susceptibilities observed in external fields applied along three different surfaces of an as…
We have analyzed the mechanisms and the efficiency of the 1.54 μm electroluminescence from Er-doped crystalline Si. Optical doping of a 0.25 μm deep p+−n+ junction was achieved by multiple Er and O implants which realize a uniform concentration of 1019 Er/cm3 and 1020 O/cm3 from 0.2 to 0.9 μm from the surface. It has…
A small number of bifunctional monomers are mixed with a nematic liquid crystal (LC) and cured with a distributed electric field, which is produced by a circular-hole-patterned electrode structure. A gradient type of lens, that is, a LC microlens, is investigated for various polymer concentrations. Addition of 3% poly…
The possibility of the existence Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state in quasi-low-dimensional organic superconductors is discussed. The critical field and the wave number q of the spatial oscillation are calculated on the basis of a tight binding model of κ- [BEDT- TTF] 2 I 3 , as an example. The critical fi…
An aluminum wire-grid polarizer whose period is 0.39 microm has been fabricated on a quartz substrate by electron-beam direct-writing lithography and the lift-off method. By using the s -polarization resonance effect and optimizing structural parameters, characteristics such as a loss of less than 20% and an extinctio…
It is generally accepted that biodegradation of poly(etheruethane urea) (PEUU) involves oxidation of the polyether segments on the surface where leukocytes are adhered. The influence of dissolved oxygen, which is known to control oxidation of polymers in more traditional environments, was explored in this study. Speci…
The present study is aimed at clarifying some of the factors which affect the formation and direction of a liquid jet in a collapsing cavity and the pressures induced on a nearby rigid boundary. The flow can be accurately represented by a velocity potential leading to the use of boundary integral methods to compute bu…
Using high-resolution electron energy-loss spectroscopy the surface-phonon dispersion of graphite has been determined in the \ensuremath{\Gamma}K direction over the whole energy range and the whole Brillouin zone. Born--von Karman model calculations are used to describe the dispersion relations. An unexpected result i…
Spherical, monodispersed, ferromagnetic, metallic particles of different compositions were obtained by the polyol process with a mean radius ranging from 30 nm to 1 μm. The microwave permeability of metallic particles-dielectric matrix composites were studied in the range of 0.1–18 GHz. In the wide particle size range…
Strong photoluminescence from silicon-ion-implanted thermal ${\mathrm{SiO}}_{2}$ film was investigated under various conditions. The photoluminescence spectrum of as-implanted samples or samples annealed in ${\mathrm{N}}_{2}$ at a temperature below 1000 \ifmmode^\circ\else\textdegree\fi{}C consists of three bands cent…
We have studied photoluminescence (PL) properties of surface-oxidized Si nanocrystals fabricated with a ${\mathrm{SiH}}_{4}$ plasma cell. The size dependence of the PL spectrum, the PL decay dynamics, and site-selective excitation spectroscopy show that the efficient and broad PL band around \ensuremath{\sim}1.65 eV o…
Thin-film ferroelectric capacitors consisting of PbZr0.53Ti0.47O3 sandwiched between La0.5Sr0.5CoO3 electrodes have been deposited using pulsed laser deposition. The combination of oxidic perovskite-type materials results in capacitors with a coercive field (Ec) which is comparable with values for bulk ceramics. Textu…
Effects of chemical and external pressures have been investigated on the two types of charge-ordering (CO) systems of perovskite manganites with the use of single-crystal specimens: One is ${\mathrm{Nd}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Sr}}_{\mathrm{x}}$${\mathrm{MnO}}_{3}$ with moderate CO instability…
Using a semiempirical tight-binding approach modified through introduction of a deformation potential, we have calculated the effects of uniaxial stress on the electronic density of states of carbon tubules. For zigzag tubules (n,0) the gap varies linearly with stress and independently of diameter: |${\mathrm{dE}}_{\m…
Polarization-dependent far-infrared reflectivity measurements were carried out on single crystals of anatase ${\mathrm{TiO}}_{2}$ . The results were analyzed to yield the dielectric dispersion properties of anatase in the lattice fundamentals regime. The frequencies (in ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ ) of…