Materials Literature
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The preparation and characterization of high surface area ruthenium/carbon aerogel composite electrodes for use in electrochemical capacitors is reported. These new materials have been prepared by the chemical vapor impregnation of ruthenium into carbon aerogels to produce a uniform distribution of adherent ≈20 Å nano…
A systematic spectroscopic study of the ${4f}^{7}$ energy levels of ${\mathrm{Gd}}^{3+}$ in ${\mathrm{LiYF}}_{4}$ in the vacuum-ultraviolet spectral region $(50000--70000{\mathrm{cm}}^{\mathrm{\ensuremath{-}}1})$ is reported. Using energy-level calculations, all observed spectral lines could be assigned to free-ion te…
The recently developed PSI-BLAST method for sequence database search and methods for motif analysis were used to define and expand a superfamily of enzymes with an unusual nucleotide-binding fold, referred to as palmate, or ATP-grasp fold. In addition to D-alanine-D-alanine ligase, glutathione synthetase, biotin carbo…
A model of single-bubble sonoluminescence (SBSL) is constructed. In the model, the temperature is assumed to be spatially uniform inside the bubble except at the thermal boundary layer near the bubble wall even at the strong collapse based on the theoretical results of Kwak and Na [Phys. Rev. Lett. 77, 4454 (1996)]. I…
Alumina thin films with a roughness of 20 to 50 nm were formed by immersing porous alumina gel films prepared by the sol‐gel method in boiling water. When hydrolyzed fluoroalkyltrimethoxysilane was coated on the alumina films, the contact angle for water was increased with an increase of immersion time, and immersion…
We have studied the optical properties of novel semiconductor nanosheets of Ti 1 - δ □ δ O 2 4δ- (δ ∼ 0.09; □, vacancy) which were obtained by delaminating a layered titanate into elementary host layers. A uniform thickness in subnanometer scale as well as high crystallinity resulted in a sharp absorption onset with a…
Although they often appear to be permanent, metals are unstable in their service environments and are susceptible to degradation by corrosion. Corrosion occurs when protective mechanisms have been overlooked, break down, or have been exhausted, leaving the metal vulnerable to attack by hostile environments. Control of…
In this paper we describe polymers of two metallorotaxane systems, Rot( 1,M) and Rot( 2,M) (M = Zn 2+ or Cu 1+ ), which are formed by complexing a macrocyclic phenanthroline, a 5,5‘-bis([2,2‘-bithiophen]-5-yl)-2,2‘-bipyridine (ligand 1 ) or 5,5‘-bis(3,4:3‘,4‘-bis(ethylenedioxy)[2,2‘-bithiophen]-5-yl)-2,2‘-bipyridine (…
A specialized extracellular matrix of proteins and polysaccharides controls the morphology and packing of calcium carbonate crystals and becomes occluded within the mineralized composite during formation of the molluscan shell and pearl. We have cloned and characterized the cDNA coding for Lustrin A, a newly described…
The performance of any material in the human body is controlled by two sets of characteristics: biofunctionality and biocompatibility. With the wide range of materials available in the mid-1990s, it is relatively easy to satisfy the requirements for mechanical and physical functionality of implantable devices. Therefo…
The alignment and superposition of protein structures are sometimes complicated by the presence of insertions or deletions in one structure or the other. The program ALIGN [Satow, Cohen, Padlan & Davies (1986). J. Mol. Biol. 190, 593–604] was written to address this problem. The program provides information in its ana…
Abstract Lithium may constitute an essential element in micas, yet it cannot be detected by the electron microprobe. Since Li is critical for correctly classifying micas and properly calculating their formulae, several methods have been proposed to overcome this analytical deficiency. We offer empirical relationships…
Abstract Molecules adsorbed on evaporated thin metal films exhibit enormously strong infrared absorption. The thin metal films that exhibit the surface-enhanced infrared absorption (SEIRA) consist of metal particles much smaller than the wavelength of light. Electric field associated with the incident infrared radiati…
A mean-field, lattice-based model of polymer melt intercalation in organically-modified mica-type silicates (OLS) has been developed. In general, an interplay of entropic and energetic factors determines the outcome of polymer intercalation. Free energy curves and their dependence on energetic and entropic factors sug…
We report experiments on bilayer light emitting diodes made with organically capped CdSe(CdS) core/shell type semiconductor nanocrystals and an electroluminescent (EL) semiconducting polymer [poly(p-phenylenevinylene) or PPV]. The devices emit from red to green with external quantum efficiencies of up to 0.22% at brig…
The effect of silicate functionalization, anneal temperature, polymer molecular weight, and constituent interactions on polymer melt intercalation of a variety of styrene-derivative polymers in alkylammonium-functionalized silicates is examined. Hybrid formation requires an optimal interlayer structure for the organic…
A detailed study of the kinetics and mechanism of micromolecular transport in cellulose acetate films containing 2.0 acetate groups per glucose unit (CA-2.0) is reported. The polymer was prepared by controlled hydrolysis of CA-2.45 films studied in preceding articles. The same series of simple liquid penetrants varyin…
A novel GPC calculation method has been developed for characterizing star-shaped styrene–butadiene block copolymers (SBS). This method enables us to determine the degree of branching (number of arms per molecule) of the synthesized polymer without the need of a priori measurement of the true molecular weights of the S…
The mechanical properties of polypropylene depend critically on the crystallizability of the chains, which depends in turn on their stereochemical structures. These dependences were investigated using Monte Carlo methods to generate chains having various stereochemical sequences and then scrutinizing parallel arrays o…
The peroxide-initiated grafting of vinyltrimethoxysilane (VTMS) onto dodecane has been examined as a model for grafting onto polyethylene. At 160°C, 2% v/v VTMS and 0.08% v/v initiator, the monomer was grafted onto dodecane with a 59% conversion and an average of 2.37 VTMS grafts per dodecane. These values were obtain…