Materials Literature
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Thin films of hafnium oxide have been prepared by using a dual ion beam sputtering system. A study of their physical properties is reported. In particular, structural and compositional characterization was performed by means of x-ray diffraction and x-ray photoelectron spectroscopy techniques, showing a mixture of amo…
Clay mineral assemblages of a soil chrono-association comprising five fluvial surface members (QGH1 to QGH5) of the Indo-Gangetic Plains between the Ramganga and Rapti rivers, north-central India, demonstrate that pedogenic interstratified smectite–kaolin (Sm/K) can be considered as a potential indicator for paleoclim…
New photochromic carotenoid-like chromophores containing the dithienylperfluorocyclopentene fragment have been synthesized and characterized by UV/Vis spectroscopy. The quantum yields of the photochromic forward and back reactions of these compounds have been determined and are found to decrease sharply with increasin…
In the Adamello-Brenta Regional Park (Trentino, Italy), the diatom communities of 30 mountain springs, 15 on crystalline and 15 on carbonate substratum, were studied between 1993 and 1996. Two of them, one from each substratum type, were sampled monthly for a more detailed investigation of seasonal changes in communit…
Hydrogen bond strength depends on both temperature and pressure. The gradient for hydrogen bond strength with temperature, or pressure, depends upon the hydrogen bonded structure. These features create an intimate connection between quantum mechanics and thermodynamics in the structure of liquid water. The equilibrium…
This manuscript reports the demonstration of strong interparticle electromagnetic coupling in nanoparticle:molecule:nanoparticle sandwiches. These assemblies were prepared by adsorption of cytochrome c (Cc)-coated colloidal Au nanoparticles onto aggregated colloidal Ag. Surface enhanced Raman scattering (SERS) spectra…
The electronic structure of [Cr(tren)(3,6-DTBSQ)] 2+, where tren is tris(2-aminoethyl)amine and 3,6-DTBSQ is 3,6-di- tert -butylorthosemiquinone, has been studied by self-consistent-field non-local gradient-corrected density functional theory. The results are consistent with a Heisenberg exchange formulation where a C…
Galvanic corrosion of copper (UNS C11000), 1018 carbon steel (CS, UNS G10180), aluminum alloy 3003 (UNS A93003), and zinc (UNS Z32121) coupled to cathodes of UNS N08367 was tested with and without natural marine biofilms on the cathode surface. Weight losses were significantly higher, and corrosion currents were up to…
Complexes of discotic liquid crystals would ideally possess the conductive properties of semiconductors and metals as well as the highly anisotropic mechanical, optical and structural properties of liquid crystals. High-resolution X-ray diffraction is used by the authors to study the structure of a liquid-crystalline…
The degradation of poly(propylene fumarate-co-ethylene glycol) hydrogels was examined in vitro in phosphate-buffered saline at pH 7.4 and in vivo in a subcutaneous rat model. These hydrogels have potential application as biodegradable, injectable cardiovascular stents, and, as such, their mass loss, dimensional change…
Obtaining high resolution x-ray photoemission spectroscopy (XPS) spectra of insulating samples has long been a problem because of difficulty controlling sample surface potentials. A flood of low energy electrons has traditionally been used to control surface potential, but as monochromatized instruments with small, in…
Additions of Bi 2 O 3 were used to promote grain growth and to increase magnetic permeability during sintering of MnZn ferrites. The results showed that small additions of Bi 2 O 3 of <0.05 wt% remarkably increase the permeability of MnZn ferrites. On the other hand, addition of 0.05 wt% Bi 2 O 3 induced the format…
The oxidative durability of a SiC‐SiC composite with Hi‐Nicalon fiber and a BN interphase was investigated at 800°C (where pesting is known to occur in SiC‐SiC composites) for exposure durations of up to 500 h and in a variety of oxidant mixes and flow rates, ranging from quasi‐stagnant room air, through slow‐flowing…
The properties of convex gratings fabricated by electron-beam lithography are investigated. Three grating types are shown. The first is a single-panel, true blazed grating in which the blaze angle stays constant relative to the local surface normal. This grating provides high peak efficiencies of approximately 88% in…
ABSTRACT Tensile strength (TS), percent elongation (%E), oxygen permeability (OP), and water vapor permeability (WVP) of lactic acid and rennet precipitated casein‐based edible films were studied to determine the effect of protein to plasticizer ratio (0.6:1, 1:1, 1.4:1) and plasticizer type (sorbitol, glycerol) on th…
Abstract A method for predicting the shape of solution‐grown organic crystals is presented. The shapes depend on properties of their internal crystal structure, as well as on the processing environment. The model developed here can account for the effects of solvent and may be extended to account for the influence of…
The binary compounds Ca 3 Al 2 O 6 (C 3 A), Ca 12 Al 14 O 33 (C 12 A 7 ), CaAl 2 O 4 (CA), CaAl 4 O 7 (CA 2 ), and CaAl 12 O 19 (CA 6 ) in the CaO‐Al 2 O 3 system have been synthesized as high‐compound‐purity ceramic powders by using the self‐propagating combustion synthesis (SPCS) method. Materials characterization o…
A nuclei size measurement technique is developed, based on a dispersion relation for propagation of sound waves through a bubbly liquid. This is used to relate the attenuation and phase velocity of a sound wave to the bubble population, leading to two integral equations. These equations are ill posed, and require spec…
Crystallography at sub-atomic resolution permits the observation and measurement of the non-spherical character of the electron density (parameterized as multipoles) and of the atomic charges. This fine description of the electron density can be extended to structures of lower resolution by applying the notion of tran…
The electrochemistry of (OEC)M where M = Mn, Co, Ni, or Cu and OEC is the trianion of 2,3,7,8,12,13,17,18-octaethylcorrole was investigated in dichloromethane, benzonitrile, or pyridine, and the oxidized compounds were characterized by UV−visible and/or ESR spectroscopy. The first two oxidations of the Co, Ni, and Cu…