Materials Literature
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Aliphatic [n]-polyurethanes were obtained by catalytic polycondensation of suitable α-hydroxy-ω-O-phenyl urethanes (III). 1H and 13C NMR analyses of the resulting [n]-polyurethanes (3 a–g) show a uniform microstructure consisting of urethane groups only, and with carbonate and urea groups being absent. The [n]-polyure…
Linear response density functional calculations of the structures, phonon spectra, and thermal expansion have been performed for the hexagonal silicate \ensuremath{\beta}-eucryptite $[\ensuremath{\beta}\ensuremath{-}{\mathrm{LiAlSiO}}_{4}]$ and related materials, extending and refining earlier work using direct diagon…
High-voltage on-site tests of extruded insulation cables are necessary to check the quality of the installation of the system. The test voltage should simulate the stress under service conditions, and generate the same failure mechanism. With respect to an optimum design of test systems, a frequency range of 20 to 300…
Silicon carbide with aluminum, boron, and carbon additions (ABC‐SiC) was hot‐pressed to full density. The samples were examined by transmission electron microscopy (TEM), with an emphasis on high‐resolution electron microscopy (HREM). Amorphous grain boundary interlayers, typically less than 2 nm wide, were formed bet…
Membranes made from 4 commercial poly(carbonate urethanes): Carbothane (CB), Chronoflex (CF), Corethane 80A (CT80), and Corethane 55D (CT55), and from 2 poly(ether urethanes): Tecoflex (TF) and Tecothane (TT) were prepared by solution casting and sterilized by either ethylene oxide (EO) or gamma radiation. Their bioco…
Nonrandom porous mullite ceramics with controlled pore geometry have been fabricated using a lost mold process, where the molds were fabricated using the fused deposition process from CAD data. The pore geometry of molds was varied to achieve different pore sizes and shapes. These porous ceramic structures were then t…
Ultrafine grained (∼1 µm) steels are currently the subject of a great deal of research worldwide. They offer the prospect of very high strength with very high toughness from standard steel compositions, and recently it has been shown that such fine grains can be obtained from the hot rolling mill rather than merely fr…
Rough silver surfaces enhance the Raman scattering of adsorbed molecules by many orders of magnitude. The size, shape, and surroundings of the metal particles greatly influence the resulting Raman intensities. With the controlled formation of well-separated silver islands, direct investigation of the local origin of t…
The high-$T$ ``orthorhombic-cubic'' Jahn-Teller (JT) transition of a polycrystalline sample of ${\mathrm{LaMnO}}_{3}$ is studied by Raman scattering. A ${\mathrm{CaMnO}}_{3}$ ceramic sample is used as a reference compound. Dramatic broadening of the ${\mathrm{LaMnO}}_{3}$ Raman modes are observed as T approaches the J…
Several new tripodal tris-urea derivatives are prepared and found to be efficient gelling agents for organic solvents. The structure and thermotropic properties of the gels are studied by electron microscopy, differential scanning calorimetry (DSC) and FT-IR spectroscopy. Remarkably, the range of solvents to be gelled…
The chemical reactions at the pore tip depend strongly on the choice of the electrolyte. They define the chemical transfer rate, properties and kinetics of the surface passivation, and ultimately the crystal orientation dependence of pore formation. In addition, there exists a number of processes which stabilize pore…
Macroporous silicon is prepared with strongly modulated pore diameter by applying a sawtooth-like illumination profile. Taking into account diffusion limited mass transport, 25 perfectly identical modulations have been achieved, corresponding to a total pore depth of 200 μm. Qualitatively the pore growth may be well c…
Dolomite solubility in water has been measured by a number of different methods during the past several decades, yielding inconsistent and unreliable results that vary more than three orders of magnitude. The most commonly used best value for dolomite solubility in water is based on HCl solution calorimetry at 300.15…
A novel spiro trialicyclic dianhydride, rel[1S,5R,6R]-3-oxabicyclo[3.2.1]octane-2,4-dione-6-spiro-3′-(tetrahydrofuran-2′,5′-dione) (DAn) was synthesized from itaconic anhydride (1) and cyclopentadiene via a Diels-Alder reaction, nitric acid oxidation, and the subsequent dehydration with acetic anhydride. The structure…
We have investigated the analysis of smoke and gases generated under various thermal decomposition conditions of polyurethane (PU) and fire retarded polyurethane coatings. The use of Fourier Transform Infrared Analysis has allowed the continuous detection of a number of the most important fire gases. We have shown tha…
Combinatorial mutagenesis and in vivo selection experiments previously afforded functional variants of the AroH class Bacillus subtilis chorismate mutase lacking the otherwise highly conserved active site residue Arg(90). Here, we present a detailed kinetic and crystallographic study of several such variants. Removing…
The influence of doping of the Sr x Ba 1− x Nb 2 O 6 ( x =0.61) crystals (SBN-0.61) by rare-earth element (RE) dopants has been investigated. Taking into account the data available in the literature, it is demonstrated that the introduction of all rare-earth metals is accompanied by a substantial decrease in the tempe…
The residual thermoelastic stresses were studied in Al 2 O 3 –ZrO 2 (monoclinic zirconia, m ‐ZrO 2 ) and Al 2 O 3 –ZrO 2 (Y 2 O 3 ) (tetragonal zirconia, t ‐ZrO 2 ) fibrous eutectics that were produced via the laser floating zone method, using different piezospectrosocopic probes. The luminescence of the R ‐lines of r…
Boron‐rich boron nitride (BN) films have been prepared on Si and SiO 2 /Si substrates by the vacuum pyrolysis of spin‐coated polyborazine films. Physical properties of the prepared films such as film strength, thermal conductivity, and dielectrics were determined. The BN films vacuum‐pyrolyzed at 900°C showed residual…
The effect of reaction temperature on the catalytic and photocatalytic oxidation of ethylene on unplatinized and platinized versions of a TiO 2 /ZrO 2 mixed-oxide thin-film catalyst is presented in this study. Ethylene conversion data collected using a recirculating tubular reactor are analyzed using a half order mode…