Materials Literature
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Methods for dynamic characterization of composite materials were extended and applied to the study of strain rate effects under transverse compression as well as shear. Falling weight impact and Split Hopkinson Pressure Bar systems were developed for dynamic characterization of composite materials in compression and s…
Microbial proline 4-hydroxylases, which hydroxylate free L-proline to trans-4-hydroxy-L-proline, were screened in order to establish an industrial system for biotransformation of L-proline to trans-4-hydroxy-L-proline. Enzyme activities were detected in eight strains, including strains of Dactylosporangium spp. and Am…
The solution catalytic lifetimes of polyoxoanion- and tetrabutylammonium-stabilized Rh(0) nanoclusters have been investigated, including comparison to the lifetimes of [RhCl(PPh 3 ) 3 ] (Wilkinson's catalyst), [(1,5-COD)Rh(CH 3 CN) 2 ]BF 4, and 5% Rh/Al 2 O 3 under identical conditions. These Rh(0) nanoclusters, deriv…
The electronic structure and magnetic properties of doped manganites surfaces are investigated. It is assumed that, at the outermost layer, the environment of the Mn ions does not have cubic symmetry. The ${e}_{g}$ orbitals are split and the double exchange mechanism is weakened. The charge state of the Mn ions is mod…
First calculations of the vibrational density of states (VDOS), the character of the vibrational modes, and the polarized Raman spectra of depolymerized alkali silicate glass with 20 mol % ${\mathrm{Na}}_{2}\mathrm{O}$ $({\mathrm{Na}}_{2}{\mathrm{Si}}_{4}{\mathrm{O}}_{9}$ glass) using Kirkwood-type potential and compu…
Nanometre precursor powders of ZnO and various additives are synthesised by a new technology, namely chemical coprecipitation and plasma pyrolysis. Transmission electron microscopy (TEM) and the Brunauer–Emmett–Teller (BET) method are employed to illustrate the precursor powders' properties. The ZnO and additive compo…
Viscoplastic self-consistent polycrystal models have been successful in addressing and explaining features of plastic deformation which cannot be treated with the Taylor condition of isostrain. In particular, these models have been applied to the simulation of plastic deformation and texture development in materials w…
Fluorinated amorphous carbon thin films (a-C:F) for use as low-dielectric-constant interlayer dielectrics are deposited by helicon-wave plasma enhanced chemical vapor deposition. To improve their thermal stability, the feasibility of adjusting the fluorine-to-carbon (F/C) ratio by changing the deposition pressure was…
Sol‐gel derived high surface area carbon‐ruthenium xerogels were prepared from carbonized resorcinol‐formaldehyde resins containing an electrochemically active form of ruthenium oxide. The electrochemical capacitance of these materials increased with an increase in the ruthenium content indicating the presence of pseu…
Characterization of microstructures containing small grains or low-angle grain boundaries by electron backscattered diffraction (EBSD) is limited by the spatial and angular resolution limits of the technique. It was found that the best effective spatial resolution (60 nm) for aluminium alloys in a tungsten-filament sc…
The design and synthesis of a new dendrimer–poly(ethylene glycol) (PEG) conjugate that may be used as a model drug carrier are described. The starting material is a polyether dendrimer with two different types of chain end functionalities. The dendritic assembly is made water soluble through attachment of short PEG ch…
Iron and cobalt porphyrins (FeP and CoP) are utilized as electron-transfer mediators to effect photochemical reduction of CO 2 in homogeneous solutions. The species that activate and reduce CO 2 are the Fe 0 P and Co 0 P formed by reduction of the starting materials. Reduction of the metalloporphyrins (MP) is achieved…
Heteroepitaxial BaTiO 3 films of various thicknesses ranging from 12 nm to 79 nm were prepared on SrRuO 3 /SrTiO 3 substrates by radio-frequency magnetron sputtering employing a two-step deposition technique, and the crystallographic and ferroelectric properties of the heteroepitaxial films were evaluated. A ferroelec…
High‐temperature piezoelectric ceramics based on W 6+ ‐doped Bi 4 Ti 3 O 12 (W‐BIT) were prepared by both the conventional mixing oxides and the chemical coprecipitation methods. Sintering was carried out between 800° and 1150°C in air. A rapid densification, >99% of the theoretical density (rho th ) at 900°C/2 h,…
In this article we present a detailed study of the electronic structure from various Mn-based Heusler alloys using x-ray photoelectron spectroscopy (XPS) and x-ray emission spectroscopy (XES) techniques. Performing the measurements on the Mn-$2p$ core levels as well as on the valence-band states we arrive at a more or…
Sorption to mineral surfaces is an important process controlling the mobility and stability of natural organic matter (NOM) in soil, yet only knowledge of the reversibility of this process enables the prediction of element cycling and NOM‐induced transport in soils. We have elucidated the desorption of mineral‐bound N…
1,2-Bis(2-methyl-6-nitro-1-benzothiophen-3-yl)perfluorocyclopentene was found to undergo a reversible photochromic reaction in the single-crystalline phase. Upon irradiation with 366-nm light, the single crystal turned green with keeping the crystal shape. The colored crystal showed dichroism. When the crystal was rot…
Diatoms are a group of unicellular microalgae that are encased in a highly ornamented siliceous cell wall, or frustule. Pennate diatoms have bilateral symmetry and many genera possess an elongated slit in the frustule called the raphe, a feature synonymous with their ability to adhere and glide over a substratum, a pr…
The vibrational modes of carbon nanotubes and nanoropes are studied. The Raman and infrared active modes are determined for armchair, zigzag, and chiral nanotubes. High-energy Raman and infrared modes exhibit distinct characteristic patterns for armchair, zigzag, and chiral tubes. In the nanorope the intertube interac…
We observe three distinct behavioral states in field emission from single-walled carbon nanotubes between temperatures of 300 and 1800 K. At room temperature, nanotubes emit through adsorbate states correlated to the presence of water. These states are removed above 900 K. After adsorbate removal, the apparently clean…