Materials Literature
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We present a first-principles pseudopotential study of the structural and electronic properties of \ensuremath{\beta}-${\mathrm{Si}}_{3}$${\mathrm{N}}_{4}$ and the hypothetical compound \ensuremath{\beta}-${\mathrm{C}}_{3}$${\mathrm{N}}_{4}$. \ensuremath{\beta}-${\mathrm{C}}_{3}$${\mathrm{N}}_{4}$, which is ${\mathrm{…
Absolute total electron scattering cross sections for water molecules measured in the 25-300 eV incident energy range using a linear electron transmission device are presented. The results are compared with previous data.
Cross sections of RF sputtered MoS 2 thin films are investigated using lattice resolution transmission electron microscopy and electron diffraction. The results are compared with X-ray diffraction measurements. The films have a (001) texture (type II) in the first nanometres near the interface and a conventional (100)…
The off-centre displacement delta of a Li ion in KTaO3 and the surrounding lattice distortion is calculated using a nonlinear shell model developed for the pure lattice. The method of the static lattice Green function is applied and the range of the Li dipole forces is limited to a few lattice constants. A short range…
We report high-resolution angular-resolved electron-energy-loss measurements of the cross section of surface-plasmon excitation. The intensity shows a pronounced minimum as a function of exchanged momentum near ${\mathit{q}}_{\mathrm{\ensuremath{\parallel}}}$=0 whose position depends on impact energy and angle of inci…
The preparation and properties of K 2 Ca 2 (SO 4 ) 3 doped with Eu are described. The phosphor is five times more sensitive than CaSO 4 :Dy. It has a linear response, simple glow curve, emission peaking at 415 nm, negligible fading and excellent reusability. It is claimed that this phosphor can replace CaSO 4 :Dy.
A three-dimensional random-tiling icosahedral quasicrystal is studied by a Monte Carlo simulation. The hypothesis of long-range positional order in the system is confirmed through analysis of the finite-size scaling behavior of phason fluctuations and Fourier peak intensities. By investigating the diffuse scattering w…
We have performed angle-resolved photoemission experiments and density-functional band calculations for NiO and CoO. The measured oxygen bands are in excellent agreement with the calculation, but the measured cation 3d dispersion is only about 25% of the calculated one. We have also demonstrated the effects of the ant…
Zinc Borate (2Zn0·3B 2 0 3 ·3.5H 2 0) is a unique multifuntional fire retardant. It can function as a flame retardant, smoke suppressant, afterglow suppressant, as well as an anti-tracking agent in polymers. It has been used extnesively as a fire retardant in PVC, polyolefin, nylon, polyester, epoxy, acrylic, urethane…
Possible routes to major advances in flame retardant efficacy are surveyed with reference to reported instances of unusually effective systems, and with reference to theory. In flame studies, some highly efficient quenching species have been noted. Char formation is a major factor in flame retardancy, and there are se…
Since charring is an important route to flame retardancy, research has been done to better understand why different aromatic engineering polymers yield differing amounts of char upon combustion. Studies were made using thermogravimetric analysis, differential scanning calorimetry, electron spin resonance, infrared and…
This paper reviews some of the more important models and mechanisms of gas diffusion in rubbery and glassy polymers in light of recent experimental data.
The history of polymer fire retardance is reviewed from its inception with the early Egyptians to the most recent developments in intumescent fire retardants and inherently fire retardant polymers.
The effects of molecular order on the gas transport mechanism in polymers are examined. Generally, orientation and crystallization of polymers improves the barrier properties of the material as a result of the increased packing efficiency of the polymer chains. Liquid crystal polymers (LCP) have a unique morphology wi…
Abstract High-resolution 11B magic-angle-spinning (MAS) NMR investigations of boric oxide and alkali borate glasses have been carried out. The chemical shift of the trigonal boron shows anomalous behaviour around 10 mol. % alkali oxide. In an attempt to explain this unusual feature, we have carefully examined the stru…
A p(2×2)surface reconstruction is observed over the 800–900 °C range for SrTiO3 (100), the temperature range which is used in the oxygen anneal of Y, Ba, Cu layers on SrTiO3 (100) substrates in the synthesis of high Tc superconducting thin films. As observed by Auger electron spectroscopy, high-temperature annealing c…
The kinetics of microphase separation and ordering of a diblock copolymer onto a lattice has been studied using time-resolved high-resolution small-angle x-ray scattering. The measurements show rapid formation of spherical domains after quenching and a subsequent ordering of the spheres. The results are discussed with…
The mode coupling equations describing the ideal glass transition in simple liquids are generalised to treat binary mixtures. These equations are solved numerically to obtain the phase diagram, the glass order parameters, and the exponents ruling the long time dynamics of a soft sphere model for which numerical simula…
Amorphous C:H containing silicon film shows an extremely low friction coefficient of 0.007 when the film is rubbed with a steel ball in a vacuum. This film is deposited on steel with an electron cyclotron resonance plasma of ethylene and silane. Polarized microinfrared spectroscopy reveals that high lubrication perfor…
The scanning photoelectron microscope at the National Synchrotron Light Source (NSLS) has recently recorded micrographs with a resolution below half a micron. To demonstrate elemental and chemical sensitivity at the submicron level, an artificial structure consisting of Al and SiO2 lines on a boron-doped silicon subst…