Materials Literature
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We have examined the band gap of a layered B${\mathrm{C}}_{2}$N compound semiconductor. The spectroscopic measurements of scanning tunneling microscopy showed the characteristics of a semiconductor with a band gap energy of 2 eV. The valence band edge measured by x-ray photoelectron spectroscopy was 0.95 eV below the…
In several experiments with soils and mineral phases, extraction of Al (and Fe) by pyrophosphate reagent (0.1 M Na4P2O7, pH 9.5 - 10.5) was tested with regard to its use for the characterization of Al in humus complexes. Results showed that, independent of the soil content of organic C, pyrophosphate reagent removed n…
The shape of a drop centered in an axisymmetric extensional flow is determined by the viscous stresses that deform the drop and surface tension γ′ that resists the deformation. The ratio of these stresses is given by the capillary number, Ca. When Ca is small enough, the drop attains a steady shape. However, above a t…
The electrical conductivity of Sr1−xLaxTiO3 ceramics (x≤0.4) and single crystals (x≤0.1) was investigated in the temperature range between 19 and 1673 K. The mobility was calculated from the carrier concentration, n, which was determined by Hall measurements as well as by a chemical Ti3+ titration. The mobility of the…
Resource‐based physiology of the eight important planktonic diatom species in the large lakes of the Yellowstone region can be used to explain their relative abundances and seasonal changes. The diatoms are ranked along resource ratio gradients according to their relative abilities to grow under limitation by Si, N, P…
In this paper, we report a generalized form for the range parameter governing the pair interaction between soft ellipsoidal particles. For nonequivalent uniaxial particles, we extend the Berne-Pechukas Gaussian overlap formalism to obtain an explicit expression for this range parameter. We confirm that this result is…
Carbon-coated iron, cobalt, and nickel particles were produced by an arc discharge process modified in the geometry of the anode and the flow pattern of helium gas. Field emission scanning electron microscopy shows that the resulting material consists of only carbon-coated metal particles without any nanotubes or othe…
The effects of the dopants, Mg 2+ , Sr 2+ , Sc 3+ , Yb 3+ , Gd 3+ , La 3+ , Ti 4+ , Zr 4+ , Ce 4+ , and Nb 5+ , on the grain boundary mobility of dense Y 2 O 3 have been investigated from 1500° to 1650°C. Parabolic grain growth has been observed in all cases over a grain size from 0.31 to 12.5 μm. Together with atmosp…
The effects of the dopants, Mg 2+ , Ca 2+ , Sr 2+ , Sc 3+ , Yb 3+ , Y 3+ , Gd 3+ , La 3+ , Ti 4+ , Zr 4+ , and Nb 5+ , on the grain boundary mobility of dense CeO 2 have been investigated from 1270° to 1420°C. Parabolic grain growth has been observed in all instances. Together with atmospheric effects, the results sup…
The relevance of algae to the current debate on global biodiversity is assessed. Algal diversity is considered at the levels of richness of species and of higher taxonomic ranks and as the variety of habitats algae dominate and their functional importance in the processes they mediate.The geographical distribution of…
Two user-friendly computer programs are described for use in macromolecular X-ray crystallography, xdlMAPMAN provides an interface for electron-density map exchange between some of the most commonly used phase refinement, structure refinement and model- building programs. In addition, it contains several options to an…
Zinc oxide (ZnO) films have been deposited on 1 μm SiO2/Si (100) substrates by rf magnetron sputtering. Using a sputtering gas of pure oxygen, a pressure regime is found in which the ZnO films grow on room temperature substrates with a single (0001) orientation, small grains (crystallite sizes ∼10–15 nm), and high int…
The aim of this review is to describe many approaches to modulated crystals and quasicrystals developed in two decades after the introduction of higher-dimensional crystallography in a unified way. Much attention is focused on higher-dimensional crystallography of quasi-crystals, which is under development. After disc…
The surfaces of titanium oxide belong to the most-studied oxide systems in the surface science literature. This is in part because TiO2 surfaces and interfaces play a major role in several technological applications, e.g., as promoters in catalysis, as photocatalysts, and as gas sensors. TiO2 is a reducible oxide, i.e…
Abstract The syntheses and properties of novel, extremely strong uncharged polyaminophosphazene bases up to a high level of steric hindrance are described. Most of the systems were readily prepared in up to molar quantities and conveniently recovered from their salts. They are of appreciable to high chemical and therm…
We show that the organic salt 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium tosylate (DAST) is a very interesting material for electro-optic applications in the near infrared. The electro-optic coefficients, namely r111, r221, r331, r113, r223, and r333, were determined in the spectral range of 700 up to 1535 nm using…
Nitinol based shape memory alloys were introduced to Medicine in the late seventies. They possess a unique combination of properties including shape memory, superelasticity, great workability in the martensitic state, resistance to fatigue and corrosion. Despite these exceptional physical, chemical and mechanical prop…
The major methods of mathematical modelling of solidification and melting problems are reviewed in this paper. Different analytical methods, nowadays still used as standard references to validate numerical models, are presented. Various mathematical formulations to numerically solve solidification and melting problems…
Several methods to assess the (dis)similarity of protein structures objectively are described, some of which, when applied to non-crystallographically related protein models, are able to discriminate between significant differences and 'random noise'. Some of these methods have been used to investigate a sample of sev…
Abstract This review focuses on some aspects of the chemistry involved in the preparation of oxides by sol–gel methods. This field is opening interesting possibilities for molecular chemistry and among those presented herein are: (1) the use of precursors containing functional groups for the preparation of solids with…