Materials Literature
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Based on high-resolution electron microscopy images and convergent-beam electron diffraction patterns, structural models of decagonal quasicrystals, which have pentagonal atom-cluster columns and belong to the space groups P10m2 and P105/mmc, have been contructed by the section method. The model for the space group P1…
The two-fold degenerate alignment of nematic liquid crystals provided by obliquely evaporated SiOx layers was studied as a function of temperature. A temperature induced anchoring transition from tilted to planar alignment with more than 80 degrees between their preferred directions was found. The director in the two-…
Three new phospholipid diols, bis[2-(2-hydroxyethyldimethylammonio)ethyl]diethylene octadecylamine diphosphate (BDODP), bis[2-(2-hydroxyethyldimethylammonio)ethyl]diethylene hexadecylamine diphosphate (BDHDP), and bis[2-(2-hydroxyethyldimethylammonio)ethyl]diethylene dodecylamine diphosphate (BDDDP), together with 1,4…
We present the first systematic investigation of the differences among reference-quality ellipsometrically measured pseudodielectric function 〈ε〉 spectra of crystalline Si, which are nominally used to approximate the bulk dielectric function of this material. In addition to the expected influence of residual overlayer…
Many factors should be considered in the selection of chemical protective clothing, but the majority of selections are based on manufacturers' permeation data composed of average results for three replicates; usually no information about variability is provided. It was hypothesized that variability across batch lots m…
Abstract The theory of interdiffusion of a pair of components in multicomponent polymer mixtures is reviewed from a statistical point of view, and the foundation of the “fast” and “slow” mode theories, as well as the more recent “ANK” theory of interdiffusion is critically examined. The ANK theory reproduces the resul…
A novel InGaAs/InP micromachined thermoelectric sensor is presented. The key features of the reported sensors are the high thermal resistivity and high mobility of InGaAs lattice matched to InP, combined with a value of Seebeck coefficient that is acceptable for such applications. The anisotropic and selective surface…
Raman spectroscopy was applied to silicon carbide/carbon continuous fibre-reinforced ceramic matrix composites to study the microstructure and composition changes in the fibres in the matrices after the consolidation of the composite at high temperatures by hot pressing, and also the stress distributions in the compos…
Poly[4-(4‘,4‘,5‘,5‘-tetramethyl-3‘-oxido-1‘-oxylimidazolinium-2‘-yl)-1,2-phenylenevinylene] ( 1 ) and poly[4-[(3,5-di- tert -butyl-4-oxyphenyl)(3,5-di- tert -butyl-4-oxocyclohexa-2,5-diene-1-ylidene)methyl]-1,2-phenylenevinylene] ( 2 ) were synthesized via the polymerization of 2-bromo-4-[1‘,3‘-bis( tert -butyldimethy…
Crack-free and transparent PbTiO3 thin films with a perovskite structure were deposited on NaCl (100), Si(111), and fused quartz substrates by the sol-gel method. The crystal structure, morphology, domain structure, composition, and optical properties of the films were characterized by means of x-ray diffraction, tran…
Some results of work carried out on flame retarding of cotton and wool fabrics are reviewed.* Cotton fabrics are rendered flame retardant upon treatment with ammonium sulfamate (AS) with urea or a urea-based cross linking agent, as co-additive, in the pad-dry-cure finishing treatment, with curing at 180-200°C for one…
Two mechanisms of microbially influenced corrosion (MIC) are discussed and compared: corrosion modified by the presence of (1) sulfate-reducing bacteria (SRB) and (2) manganese-oxidizing bacteria (MOB). It is demonstrated that the nature of MIC in both cases depends on the nature of inorganic materials precipitated at…
Abstract Chlorination, bromination and iodination of bis(methylthio)tetrathiafulvalene (BMT-TTF) produced mainly the dihalogenated products (BMT-TTFX2) with small amounts of the monohalogenated derivatives (BMT-TTFX). The molecular structures of BMT-TTFBr2 and BMT-TTFBr2•I3 have been determined, and the conductivities…
The solid-state phase transformations and crystallography of equiatomic TaRu were examined by conventional and in-situ high-temperature transmission electron microscopy, with complementary experiments using X-ray diffraction and dilatometry. This alloy undergoes two displacive phase transformations on cooling from the…
Indium has replaced all of the Tl + ions in fully dehydrated fully Tl + -exchanged zeolite A by a solvent-free redox ion-exchange reaction with In metal at 623 K. The crystal structures of the zeolite before (Tl 12 Si 12 Al 12 O 48: a = 12.153(4) Å, R 1 = 0.054, and R 2 = 0.060) and after the reaction, followed by was…
The complete carbonylation mechanism for the model palladium(II) system, Pd(PH 3 )(CH 3 )(N-O) + CO → Pd(PH 3 )(COCH 3 )(N-O) (N-O = NHCHCOO - ), has been investigated employing nonlocal density functional theory (DFT) and second-order Møller−Plesset perturbation theory (MP2). Four possible mechanisms were identified,…
We used the electron-beam evaporation method in various oxygen partial pressure environments to deposit TiO(2) thin films on various glass substrates at 300 degrees C. We found the threshold oxygen partial pressures above which the film is transparent are different for films on various substrates. Below the threshold…
The effect of composition (phase), texture, microstructure and thickness on electrical properties of Pb(Zr 1- x Ti x )O 3 (PZT) films have been evaluated. Zr-rich PZT films with [111] texture have a higher remanent polarization and dielectric constant, but a lower coercive field as compared with PZT[100] films. Ti-ric…
The dissolution of calcite (CaCO 3 ) in the presence of aqueous solutions containing maleic acid ( cis -HOOC−CH CH−COOH) in the pH range 4.3−8.2 has been studied by means of atomic force microscopy utilizing a flow cell of known hydrodynamics and modelable convection/diffusion. The latter permits the interpretation of…
The development of the concept of chirality from the early work of Pasteur, van't Hoff and Le Bel to the work of Cahn, Ingold and Prelog is presented, and the constraints that chirality imposes on the symmetry of molecules - that chiral molecules may not possess an improper axis of rotation - is discussed. The relatio…