Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural, spectroscopic and theoretical studies of novel d6 fac-bromotricarbonyl(dithiooxamide)rhenium complexesPeter C. Servaas, Derk J. Stufkens, Ad Oskam, Pieter Vernooijs, Evert Jan Baerends, Dirk J. A. De Ridder, and Caspar H. StamCite this: Inorg. Chem. 1989, 28, 22,…
Abstract Tetradesmethyl‐β‐carotene is found to form aggregates in a mixed solvent of methylcyclohexane and isopentane at temperatures below 180 K. The absorption band around 470 nm (0–0 transition) of the monomer splits into a pair of absorptions (exciton bands) on aggregation, one around 400 nm and the other around 5…
Arsenic deposition onto a gold substrate was studied as a function of p H, deposition potential, and time. Deposition of less than three monolayers was observed. The rate of deposition decreased as the thickness of the deposit increased. A set of partial reactions leading to arsenic deposition was proposed. The kineti…
A mathematical model has been evolved to estimate the breaking elongation of highly twisted (3 < TM < 6) singles ring spun cotton yams from fiber characteristics. Results show that the accuracy of estimation of the proposed model is very high. The model is applicable to both carded and combed cottons.
The sweet corrosion behavior of L-80 grade downhole tubular was investigated in flowing two-phase oil-brine fluids. Depending upon percent water cut, two different phases appeared to exist: a water-continuous phase above 50% water cut and an oil-continuous phase below 50% water cut. In the oil-continuous phase, the pr…
Results of electric conductivity, permittivity and spontaneous polarization measurements for PbTiO3 single crystals with La doping up to 0.44 at % are presented. Marked influence of lanthanum doping on dielectric parameters such as permittivity and Curie temperature has been found. Considerable changes of d.c. conduct…
The adsorption of pyrene-end-labeled poly(ethy1ene glycol) (Py-PEG-Py) onto aqueous colloidal polystyrene (PS) particles is investigated by photostationary fluorescence, fluorescence decay, and photostationary fluorescence depolarization experiments. All of the spectroscopic observations on this system suggest the ass…
The formation of the icosahedral quasicrystalline phase in the Al-Cr-Fe system has been investigated by X-ray diffraction as a function of the CrxFe1–x, composition of the transition-metal (TM) quasisublattice. An optimal range was found around x = 0·6, where the icosahedral phase shows the highest degree of structura…
This article introduces an unconventional electron optical probe forming system which is particularly suitable for low beam voltages and very large specimens, such as semiconductor wafers which also require a large angle tilting. The system can produce an electron probe of less than 20 Å for a nontilting specimen at 1…
Abstract Single crystals of β 1 and polycrystals of β 2 of POP and SOS were obtained from acetonitrile solution. The crystallization behavior of the two polymorphs was almost the same in POP and SOS; rapid cooling of the solution preferentially crystallized the metastable β 2 form, and the most stable β 1 form crystal…
A search for ferroelectric nematic liquid crystals is carried out on the basis of a simple theoretical model viewing the nonspherical polar molecules as hard ellipsoids of revolution with an embedded permanent dipole oriented along the symmetry axis. The density-dipole moment-aspect ratio phase diagram of the dipolar…
The anisotropic EPR signal already observed in x-ray-irradiated yttria-stabilized zirconia is analyzed between 140 and 300 K in samples containing 12% and 24% ${\mathrm{Y}}_{2}$${\mathrm{O}}_{3}$. A temperature-dependent broadening is detected and attributed to spin-lattice interactions whose mechanisms are discussed.…
We present a theoretical calculation of the Frank elastic constants of a nematic liquid crystal made of hard spherocylinders. We use the existing relations for these elastic constants together with the direct correlation function which we obtain consistently from a free-energy density-functional approximation recently…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDepth dependence of alkali etching of poly(tetrafluoroethylene): effect of X-ray radiationR. R. Rye and G. W. ArnoldCite this: Langmuir 1989, 5, 6, 1331–1334Publication Date (Print):November 1, 1989Publication History Published online1 May 2002Published inissue 1 November 19…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGround- and excited-state properties of a photostable hemicage ruthenium(II) polypyridine complexRuth Freitag Beeston, Steven L. Larson, and Michael C. FitzgeraldCite this: Inorg. Chem. 1989, 28, 23, 4187–4189Publication Date (Print):November 1, 1989Publication History Publi…
The development of the diamond-anvil cell has stimulated Raman-scattering investigation of vibrational modes in covalent crystals. The linear pressure coefficient reported for diamond by Hanfland et at' (2.90 ± 0.05 cm-1/GPa) agrees to within mutual experimental error with the result of Boppard et aL2 (2.87±0.01 cm-1/…
Li 2 O-V 2 O 5 -SiO 2 , thin films were fabricated by the rf sputtering method. The X-ray diffraction patterns of the film annealed at 500–600°C agreed with the γ-Li 3 VO 4 phase powder pattern. The as-sputtered film had an orientation of the (001) plane parallel to the substrate. The electrical conductivity of the an…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA new class of room temperature luminescent organometallic complexes: luminescence and photophysical properties of permethylscandocene chloride in fluid solutionBrian W. Pfennig, Mark E. Thompson, and Andrew B. BocarslyCite this: J. Am. Chem. Soc. 1989, 111, 24, 8947–8948Pub…
Efficient syntheses of 2,4-dibromo- and 2,4-diiododeuteroporphyrin IX have been carried out by treating zinc(II) 2,4-bis(chloromercurio)deuteroporphyrin IX dimethyl ester (2) with bromine or iodine. Unavoidable meso-chlorination occurs when 2 is treated with chlorine and with other free-radical chlorinating agents. Re…
Some polymer radicals have been proposed as potential organic magnetic materials. In order to determine where to place the doublet or triplet centers on the side chains of a conjugated polymer chain, we have studied model dimers, i.e., isomeric bis(nitrenophenyl)acetylenes and diacetylenes. They were generated by phot…