Materials Literature
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Many organisms construct structural ceramic (biomineral) composites from seemingly mundane materials; cell-mediated processes control both the nucleation and growth of mineral and the development of composite microarchitecture. Living systems fabricate biocomposites by: (i) confining biomineralization within specific…
Abstract In the last decade crystallography has emerged as a key tool for understanding the structures of biological macromolecules, yet the crystallization techniques themselves have been perceived as difficult to perform. This book provides the first detailed and rational guide to producing crystals of proteins and…
Abstract In the North Sea, due to the extensive use of water injection for oil displacement and pressure maintenance, many reservoirs experience the problem of scale deposition when injection water starts to breakthrough. In most cases the scaled-up wells are caused by the formation of sulphate scales of Barium and St…
Abstract Urethanes of cellobiose and cellulose‐containing uretdione groups are synthesized by the reaction of aliphatic and aromatic diisocyanate uretdiones with the saccharides. The syntheses are performed as a heterogeneous reaction in dimethyl acetamide using dibutyl tin dilaurate as a catalyst, as well as a homoge…
Abstract The properties of various blends of a polyester‐type thermotropic liquid crystalline polymer (LCP) with polyethylene terephtalate, polypropylene, and polyphenylene sulfide were investigated. The polymers were blended in a twin screw extruder after which samples were injection moulded. The mechanical propertie…
Abstract The surface of polyethylene was derivatized with ester, carboxylate, amino, hydroxyl, and phosphate functional groups. α, ω bifunctional alkanes, containing on one end a primary amine, were coupled to oxidized polyethylene through an amide linkage. Polyethylene was first oxidized with chromic acid, the carbox…
A correlation between collections of the experimental values of the crystal-field parameters (P20, b20, A20) characterizing the nuclear quadrupole interaction, the ground-state and excited-state splitting for 157Gd3+ in various ionic crystals with the same type of anions has been established. The correlation consists…
We have measured the temperature dependence of valence and core x-ray photoelectron intensities for W(110). At 295 K, valence spectra are very sensitive to emission direction due to direct-transition effects, and Ienergy-integratedR valence and core photoelectron diffraction curves are similar in form, but with signif…
The ionic distribution in the high-temperature rotor phase of lithium sulphate, Li 2 SO 4 , has been reinvestigated by single-crystal neutron diffraction at 923 K. Thermal vibrational tensor terms up to the fourth rank are refined to give a better description of the space-time-averaged Li + and SO 4 2- distributions.…
Characterization of light-emitting porous Si films with x-ray photoelectron spectroscopy is reported. Only traces of O are detected on HF-etched samples, in contradiction to an earlier report that oxides are a significant component of porous Si. Si 2p and valence-band measurements demonstrate that the near-surface reg…
Paraelectric lead lanthanum zirconium titanate (PLZT) films, 150 nm thick, were deposited using a spin-coat, sol-gel process followed by a 650 °C oxygen anneal. X-ray diffraction indicated complete conversion to the perovskite phase. Sputter-deposited platinum electrodes were employed with the PLZT films to form thin-…
Second-order optical nonlinearity exists in a noncentrosymmetric crystal. We investigated a new molecular concept for noncentrosymmetric crystal structure. The Λ-shaped molecules have been found to easily form noncentrosymmetric crystals by stacking along one direction. The configuration of Λ-shaped molecules is close…
A novel method for detecting hydrogen was developed by using very thin palladium overlayer-anodic oxide film-tungsten sheet structure. Its optical reflectance is modulated by the presence of hydrogen in the ambient gas. The effect can be explained by the free electron modulation of optical constants of the oxide film.…
Many materials, including soap froths, polycrystalline alloys, ceramics, lipid monolayers and garnet films, have structures composed of either two- or three-dimensional polygonal domains separated by well defined boundaries. Usually, the surface energy of these boundaries makes the pattern unstable, causing certain gr…
Etching of Si in a variety of solutions is known to cause staining. These stain layers consist of porous material similar to that produced by anodic etching of Si in HF solutions. We have observed photoluminescence peaked in the red from stain-etched Si wafers of different dopant types, concentrations, and orientation…
We report experimental results describing the mechanical breakdown of random porous Au which is a new material specifically developed for this study. Digital image analysis was used to characterize the microstructures of the samples which varied by more than 2 orders of magnitude in length scale. The porous Au undergo…
A modified version of the random sequential adsorption model for the deposition of spherical particles onto a plane is presented. Successive particles are added via randomly positioned vertical trajectories and, if they do not stick to the plane at first contact, follow the path of steepest descent on the previously d…
Nonequilibrium states of surface composition can be extremely long-lived when polymer chains adsorb competitively. In a model system (polymethylmethacrylate adsorbed from CCl(4) onto oxidized silicon previously saturated with polystyrene), it is shown that a weakly adsorbing polymer was sterically pinned to a surface…
Molecular dynamics simulations are usually performed with a fixed number of particles in a periodic box of constant size and shape, however, there are situations in which it is desirable to carry out simulations, where the volume of the periodic box is allowed to fluctuate and the external pressure is fixed. The exter…
The amino acid sequence of mouse dihydrofolate reductase was permuted circularly at the level of the gene. By transposing the 3'-terminal half of the coding sequence to its 5' terminus, the naturally adjacent amino and carboxyl termini of the native protein were fused, and one of the flexible peptide loops at the prot…