Materials Literature
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Three‐dimensional (3‐D) computer simulations of ferroelectric domain formation and evolution were performed, using a computer simulation model based on the time‐dependent Ginsburg‐Landau equations. A cubic‐to‐tetragonal ferroelectric phase transition is considered. It is shown that the initial stage of the transition…
We compare experimentally observed electron energy loss spectra (EELS) of uranium dioxide UO2 and nickel monoxide NiO with the results of ab-initio calculations carried out by using a method combining the local spin density approximation and the Hubbard U term (the LSDA + U method). We show that by taking better accou…
In carbon dioxide (CO2) corrosion of steels, the bicarbonate ion (HCO3–) is simultaneously the buffer for carbonic acid (H2CO3), the source of iron carbonate (FeCO3) precipitation, and the product of the cathodic reaction. In addition to spatial separation of the production of Fe2+ and HCO3–, galvanic coupling between…
A model is presented which describes the effect of mechanical and materials parameters on the wear‐assisted corrosion rate of passive metals under sliding wear conditions. The model is based on a consideration of contact between the sliding surfaces at multiple asperities and it takes into account the passivation beha…
The intermediate steps of the phase transition between the metastable monoclinic ${\mathrm{VO}}_{2}(B)$ phase and the stable tetragonal rutile ${\mathrm{VO}}_{2}(R)$ phase have been studied by in situ electron microscopy. A crystallographic interpretation based on the static concentration waves theory is proposed: as…
Possible domain patterns are developed for (001) oriented (pseudocubic indexing) epitaxial rhombohedral perovskite ferroelectric (FR) films. We assume that the films are grown above their Curie temperature (TC) in a cubic paraelectric (PC) state. The rhombohedral distortion consists of a “stretch” along one of the fou…
We discuss the upconversion luminescence efficiencies of phosphors that generate red, green, and blue light. The phosphors studied are single crystals and powders codoped with Er3+ and Yb3+ and with Tm3+ and Yb3+. The Yb ions are pumped near 980 nm; transfers of two or three quanta to the codoped rare-earth ion genera…
A series of low‐toxicity gelcasting systems has been developed. The reagents used in these systems have very low acute toxicity. The new systems perform at least as well as, and in some cases better than, the original acrylamide‐based system. The development of these systems is described herein, including the search f…
Abstract Dissolution of feldspar and mica and precipitation of kaolinite require a through flow of meteoric water to remove cations such as Na + and K + and silica. Compaction driven pore-water flow is in most cases too slow to be significant in terms of transport of solids. The very low solubility of A1 suggests that…
In this paper we compare the optical properties of nanosized silver particles dispersed in hexane solution and self-assembled in a 2D or 3D network. When the particles form monolayers organized in a hexagonal network, the plasmon peak of silver nanosized particles is shifted toward lower energy, with an increase in ba…
We have manufactured cathode ray tubes (CRTs) equipped with field emitters composed of multiwalled carbon nanotubes. The fabricated CRTs (20 mm in diameter by 74 mm in length) are of a triode type, consisting of a cathode (nanotube field emitter arrays), a grid and an anode (phosphor screen). The manufactured CRTs are…
The measurement of branching ratios, cross sections and radiative lifetimes for rare earth ions in solids is considered. The methods are applied to Tm and Ho in YLF as a test case. De-activation rates for electric dipole and magnetic dipole emission are calculated for many of the lower lying manifolds in Tm:YLF and Ho…
It is well known that the Fourier analysis of X-ray diffraction peak profiles (as implemented by Warren and Averbach) can accurately determine the areaweighted average grain size of a fine-grained sample. Less well known is the fact that this method simultaneously yields a volume-weighted average grain size. Under cer…
The anisotropy of plasticity in b.c.c. metals is decomposed into two parts. The first, a variation of the Peierls stress with slip plane and sense of slip, is intrinsic to the b.c.c. structure and is reflected in the geometry of the screw dislocation core and of the generalized stacking fault energy (γ) surface. The s…
Films of zinc oxide and related compounds are electrodeposited cathodically in aqueous zinc chloride solutions using dissolved oxygen as a precursor. The influence of the precursor concentrations, pH, and deposition temperature on the growth, composition, and properties of the films are investigated by means of in sit…
The singlet oxygen luminescence method and the photochemical methods using 1,3-diphenylisobenzofuran ( DPBF ) or bilirubin ditaurate ( BDT ) as chemical quenchers were employed to determine the single oxygen quantum yields (Φ Δ ) of different phthalocyanines and tris(2,2″-bipyridyl)ruthenium(II) dichloride in dimethyl…
Tin doped indium oxide (ITO) films are highly transparent in the visible region, exhibiting high reflectance in the infrared region, and having nearly metallic conductivity. Owing to this unusual combination of electrical and optical properties, this material is widely applied in optoelectronic devices. The associatio…
The processing, electromechanical properties, and microstructure of lead zirconate titanate (PZT) ceramics over the grain‐size range of 0.1‐10 μm were studied. Using measurements over a large temperature range (15‐600 K), the relative role of extrinsic contribution (i.e., domain‐wall motion) was deduced to be influenc…
To withstand the high intracellular pressure, the cell wall of most bacteria is stabilized by a unique cross-linked biopolymer called murein or peptidoglycan. It is made of glycan strands [poly-(GlcNAc-MurNAc)], which are linked by short peptides to form a covalently closed net. Completely surrounding the cell, the mu…
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