Materials Literature
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We analyze the thermodynamics of disklike particles dispersed in a polymer matrix. Using the Somoza−Tarazona free energy functional for thin oblate ellipsoids of revolution in combination with the Flory−Huggins mixing free energy, we obtain a new expression that allows us to describe the complete (liquid, crystalline,…
We have studied singlet electronic energy transfer (EET) in two donor−bridge−acceptor series (D−B−A), in which the donor (zinc porphyrin or its pyridine complex) and the acceptor (free base porphyrin) were covalently connected by a geometrically well-defined bridging chromophore. We have investigated how the medium be…
Yttrium aluminum garnet (YAG) precursors for transparent ceramics were synthesized by the urea method under various [urea]/[metal ions] ([U]/[M]) conditions. Monophase YAG was obtained from solutions with a high [U]/[M] ratio after calcination at a temperature of 1200°C. The condition of the precipitates seemed to ind…
It has been proved that surfactant−silicate supramolecular architecture formed on a silicon substrate is strongly affected by the crystal orientation of a silicon wafer, indicating the variation of the interactions between the surfactants and the silicon surfaces. The hexagonal mesoporous silica film with aligned meso…
We report results from molecular simulations of binary aqueous solutions of the carbohydrate stereoisomers, β- d -glucose, β- d -mannose, and d -fructose over a concentration range from zero to 80 wt % carbohydrate at 300 and 270 K. It is found that increasing carbohydrate concentration has a number of striking effect…
Polyaniline-coated steel panels were studied by electrochemical impedance spectroscopy (EIS) and electrochemical noise methods (ENM). EIS data for the polyaniline sample was obtained for increasing time of immersion. An increase in charge-transfer resistance (Rct) with immersion time was observed. ENM data showed that…
High surface area conducting polymers with nanoscale dimensions are an important aim for device applications. Here is reported the polymerization and electrochemical oxidation of aniline at multiwalled carbon nanotube electrodes. Polyaniline films formed on these nanotube whiskers are oxidized more easily and produce…
An analysis of polycrystalline Au thin film interconnects of widths ranging from 850 to 25 nm, and lengths ranging from 1.0 μm to 20 nm which have been electrically stressed to the point of failure is presented. For the longer wires (widths 60–850 nm), the failure current density is typically found to be 1012 A m−2, e…
We have characterized the gene encoding fatty acid alpha-hydroxylase, a cytochrome P450 (P450) enzyme, from Sphingomonas paucimobilis. A database homology search indicated that the deduced amino acid sequence of this gene product was 44% identical to that of the ybdT gene product that is a 48 kDa protein of unknown fu…
▪ Abstract Combinatorial materials synthesis methods and high throughput evaluation techniques have been developed to accelerate the process of materials discovery and optimization. Analogous to integrated circuit chips, integrated materials chips containing thousands, possibly millions, of different compounds/materia…
We calculate the conductance of a circular constriction of radius a in an insulating diaphragm which separates two conducting half spaces characterized by the mean free path l. Using the Boltzmann equation we obtain an answer for all values of the ratio $l/a.$ Our exact result interpolates between the Maxwell conducta…
Thermally initiated cationic ring-opening polymerization of 3-ethyl-3-(hydroxymethyl)oxetane was carried out using benzyltetramethylenesulfonium hexafluoroantimonate as initiator. The resulting hydroxy-functional polyether was thoroughly analyzed by 1H and 13C NMR spectroscopy and found to have a hyperbranched archite…
Currently, the immunohistochemical evaluation of smooth muscle differentiation is usually based on desmin, which also reacts with skeletal muscle and is not present in all smooth muscle tumors, and alpha-smooth muscle actin, which reacts with myoepithelial cells. Neither marker typically reacts with gastrointestinal s…
We analyze specific-heat measurements in the temperature range $1<T<200 \mathrm{K}$ for two types of carbon nanotube samples: multiwalled tubes and ropes of single-walled tubes. The multiwalled tube sample has a specific-heat not unlike that of graphite, which we maintain is reasonable given the structural simil…
In spite of a superficial similarity with gas bubbles, the intimate coupling between dynamical and thermal processes confers to oscillating vapor bubbles some unique characteristics. This paper examines numerically the validity of some asymptotic-theory predictions such as the existence of two resonant radii and a lim…
The dynamic viscoelastic behavior of Poly(l-lactic acid) (PLLA), with molecular weights ranging from 2,000 to 360,000, have been studied over a broad range of reduced frequencies (approximately 1 × 10−3 s−1 to 1 × 103 s−1), using time–temperature superposition principle. Melts are shown to have a critical molecular we…
High surface area conducting polymers with nanoscale dimensions are an important aim for device applications. Here is reported the polymerization and electrochemical oxidation of aniline at multiwalled carbon nanotube electrodes. Polyaniline films formed on these nanotube whiskers are oxidized more easily and produce…
Density functional theory and continuum dielectric methods have been employed to evaluate the free energy of successive aqua-substitution reactions: [Mg(H 2 O) 6- m - n L m L‘ n ] 2+ mz + ny + L z → [Mg(H 2 O) 5- m - n L m +1 L‘ n ] 2+( m +1) z + ny + H 2 O. The ligands L z or L‘ y under consideration are simple organ…
This paper discusses several materials aspects which are important in the development and optimisation of Al2O3:C for both thermoluminescence and optically stimulated luminescence applications, including aspects of crystal growth, luminescence spectra, trap energy distributions and general dosimetric properties.
A simple methodology has been developed to enable a greater enhancement of fluorescence from europium (Eu 3+ )-doped silica gels containing adsorbed silver (Ag) islands. The procedure involves the preparation of Eu 3+ -doped silica gels by a sol−gel method and then immersion in a Ag sol for ca. 48 h to allow the adsor…